WorldWideScience

Sample records for biological materials electronic

  1. e-Biologics: Fabrication of Sustainable Electronics with "Green" Biological Materials.

    Science.gov (United States)

    Lovley, Derek R

    2017-06-27

    The growing ubiquity of electronic devices is increasingly consuming substantial energy and rare resources for materials fabrication, as well as creating expansive volumes of toxic waste. This is not sustainable. Electronic biological materials (e-biologics) that are produced with microbes, or designed with microbial components as the guide for synthesis, are a potential green solution. Some e-biologics can be fabricated from renewable feedstocks with relatively low energy inputs, often while avoiding the harsh chemicals used for synthesizing more traditional electronic materials. Several are completely free of toxic components, can be readily recycled, and offer unique features not found in traditional electronic materials in terms of size, performance, and opportunities for diverse functionalization. An appropriate investment in the concerted multidisciplinary collaborative research required to identify and characterize e-biologics and to engineer materials and devices based on e-biologics could be rewarded with a new "green age" of sustainable electronic materials and devices. Copyright © 2017 Lovley.

  2. Ultrafast electron microscopy in materials science, biology, and chemistry

    International Nuclear Information System (INIS)

    King, Wayne E.; Campbell, Geoffrey H.; Frank, Alan; Reed, Bryan; Schmerge, John F.; Siwick, Bradley J.; Stuart, Brent C.; Weber, Peter M.

    2005-01-01

    The use of pump-probe experiments to study complex transient events has been an area of significant interest in materials science, biology, and chemistry. While the emphasis has been on laser pump with laser probe and laser pump with x-ray probe experiments, there is a significant and growing interest in using electrons as probes. Early experiments used electrons for gas-phase diffraction of photostimulated chemical reactions. More recently, scientists are beginning to explore phenomena in the solid state such as phase transformations, twinning, solid-state chemical reactions, radiation damage, and shock propagation. This review focuses on the emerging area of ultrafast electron microscopy (UEM), which comprises ultrafast electron diffraction (UED) and dynamic transmission electron microscopy (DTEM). The topics that are treated include the following: (1) The physics of electrons as an ultrafast probe. This encompasses the propagation dynamics of the electrons (space-charge effect, Child's law, Boersch effect) and extends to relativistic effects. (2) The anatomy of UED and DTEM instruments. This includes discussions of the photoactivated electron gun (also known as photogun or photoelectron gun) at conventional energies (60-200 keV) and extends to MeV beams generated by rf guns. Another critical aspect of the systems is the electron detector. Charge-coupled device cameras and microchannel-plate-based cameras are compared and contrasted. The effect of various physical phenomena on detective quantum efficiency is discussed. (3) Practical aspects of operation. This includes determination of time zero, measurement of pulse-length, and strategies for pulse compression. (4) Current and potential applications in materials science, biology, and chemistry. UEM has the potential to make a significant impact in future science and technology. Understanding of reaction pathways of complex transient phenomena in materials science, biology, and chemistry will provide fundamental

  3. Flexible Organic Electronics in Biology: Materials and Devices.

    Science.gov (United States)

    Liao, Caizhi; Zhang, Meng; Yao, Mei Yu; Hua, Tao; Li, Li; Yan, Feng

    2015-12-09

    At the convergence of organic electronics and biology, organic bioelectronics attracts great scientific interest. The potential applications of organic semiconductors to reversibly transmit biological signals or stimulate biological tissues inspires many research groups to explore the use of organic electronics in biological systems. Considering the surfaces of movable living tissues being arbitrarily curved at physiological environments, the flexibility of organic bioelectronic devices is of paramount importance in enabling stable and reliable performances by improving the contact and interaction of the devices with biological systems. Significant advances in flexible organic bio-electronics have been achieved in the areas of flexible organic thin film transistors (OTFTs), polymer electrodes, smart textiles, organic electrochemical ion pumps (OEIPs), ion bipolar junction transistors (IBJTs) and chemiresistors. This review will firstly discuss the materials used in flexible organic bioelectronics, which is followed by an overview on various types of flexible organic bioelectronic devices. The versatility of flexible organic bioelectronics promises a bright future for this emerging area. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Damage-free vibrational spectroscopy of biological materials in the electron microscope.

    Science.gov (United States)

    Rez, Peter; Aoki, Toshihiro; March, Katia; Gur, Dvir; Krivanek, Ondrej L; Dellby, Niklas; Lovejoy, Tracy C; Wolf, Sharon G; Cohen, Hagai

    2016-03-10

    Vibrational spectroscopy in the electron microscope would be transformative in the study of biological samples, provided that radiation damage could be prevented. However, electron beams typically create high-energy excitations that severely accelerate sample degradation. Here this major difficulty is overcome using an 'aloof' electron beam, positioned tens of nanometres away from the sample: high-energy excitations are suppressed, while vibrational modes of energies electron energy loss spectra from biogenic guanine crystals in their native state, resolving their characteristic C-H, N-H and C=O vibrational signatures with no observable radiation damage. The technique opens up the possibility of non-damaging compositional analyses of organic functional groups, including non-crystalline biological materials, at a spatial resolution of ∼10 nm, simultaneously combined with imaging in the electron microscope.

  5. Advances in imaging and electron physics time resolved electron diffraction for chemistry, biology and material science

    CERN Document Server

    Hawkes, Peter W

    2014-01-01

    Advances in Imaging & Electron Physics merges two long-running serials-Advances in Electronics & Electron Physics and Advances in Optical & Electron Microscopy. The series features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science and digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains. Contributions from leading authorities Informs and updates on all the latest developments in the field.

  6. Wood-Derived Materials for Green Electronics, Biological Devices, and Energy Applications.

    Science.gov (United States)

    Zhu, Hongli; Luo, Wei; Ciesielski, Peter N; Fang, Zhiqiang; Zhu, J Y; Henriksson, Gunnar; Himmel, Michael E; Hu, Liangbing

    2016-08-24

    goal of this study is to review the fundamental structures and chemistries of wood and wood-derived materials, which are essential for a wide range of existing and new enabling technologies. The scope of the review covers multiscale materials and assemblies of cellulose, hemicellulose, and lignin as well as other biomaterials derived from wood, in regard to their major emerging applications. Structure-properties-application relationships will be investigated in detail. Understanding the fundamental properties of these structures is crucial for designing and manufacturing products for emerging applications. Today, a more holistic understanding of the interplay between the structure, chemistry, and performance of wood and wood-derived materials is advancing historical applications of these materials. This new level of understanding also enables a myriad of new and exciting applications, which motivate this review. There are excellent reviews already on the classical topic of woody materials, and some recent reviews also cover new understanding of these materials as well as potential applications. This review will focus on the uniqueness of woody materials for three critical applications: green electronics, biological devices, and energy storage and bioenergy.

  7. Wood-Derived Materials for Green Electronics, Biological Devices, and Energy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Hongli; Luo, Wei; Ciesielski, Peter N.; Fang, Zhiqiang; Zhu, J. Y.; Henriksson, Gunnar; Himmel, Michael E.; Hu, Liangbing

    2016-08-24

    goal of this study is to review the fundamental structures and chemistries of wood and wood-derived materials, which are essential for a wide range of existing and new enabling technologies. The scope of the review covers multiscale materials and assemblies of cellulose, hemicellulose, and lignin as well as other biomaterials derived from wood, in regard to their major emerging applications. Structure-properties-application relationships will be investigated in detail. Understanding the fundamental properties of these structures is crucial for designing and manufacturing products for emerging applications. Today, a more holistic understanding of the interplay between the structure, chemistry, and performance of wood and wood-derived materials is advancing historical applications of these materials. This new level of understanding also enables a myriad of new and exciting applications, which motivate this review. There are excellent reviews already on the classical topic of woody materials, and some recent reviews also cover new understanding of these materials as well as potential applications. This review will focus on the uniqueness of woody materials for three critical applications: green electronics, biological devices, and energy storage and bioenergy.

  8. Electronic materials

    CERN Document Server

    Kwok, H L

    2010-01-01

    The electronic properties of solids have become of increasing importance in the age of information technology. The study of solids and materials, while having originated from the disciplines of physics and chemistry, has evolved independently over the past few decades. The classical treatment of solid-state physics, which emphasized classifications, theories and fundamental physical principles, is no longer able to bridge the gap between materials advances and applications. In particular, the more recent developments in device physics and technology have not necessarily been driven by new conc

  9. The analysis for energy distribution and biological effects of the clusters from electrons in the tissue equivalent material

    International Nuclear Information System (INIS)

    Zhang Wenzhong; Guo Yong; Luo Yisheng; Wang Yong

    2004-01-01

    Objective: To study energy distribution of the clusters from electrons in the tissue equivalent material, and discuss the important aspects of these clusters on inducing biological effects. Methods: Based on the physical mechanism for electrons interacting with tissue equivalent material, the Monte Carlo (MC) method was used. The electron tracks were lively simulated on an event-by-event (ionization, excitation, elastic scattering, Auger electron emission) basis in the material. The relevant conclusions were drawn from the statistic analysis of these events. Results: The electrons will deposit their energy in the form (30%) of cluster in passing through tissue equivalent material, and most clusters (80%) have the energy amount of more than 50 eV. The cluster density depends on its diameter and energy of electrons, and the deposited energy in the cluster depends on the type and energy of radiation. Conclusion: The deposited energy in cluster is the most important factor in inducing all sort of lesions on DNA molecules in tissue cells

  10. Transmission microscopy of unmodified biological materials: comparative radiation dosages with electrons and ultrasoft X-ray photons

    International Nuclear Information System (INIS)

    Sayre, D.; Feder, R.; Spiller, E.; Kirz, J.; Kim, D.M.

    1977-01-01

    The minimum radiation dosage in a specimen consistent with transmission microscopy at resolution d and specimen thickness t is calculated for model specimens resembling biological materials in their natural state. The calculations cover 10 4 -10 7 eV electrons and 1.3-90 A photons in a number of microscopy modes. The results indicate that over a considerable part of the (t,d)-plane transmission microscopy on such specimens can be carried out at lower dosage with photons than with electrons. Estimates of the maximum resolutions obtainable with electrons and photons, consistent with structural survival of the specimen, are obtained, as are data on optimal operating conditions for microscopy with the two particles

  11. A New Approach to Studying Biological and Soft Materials Using Focused Ion Beam Scanning Electron Microscopy (FIB SEM)

    International Nuclear Information System (INIS)

    Stokes, D J; Morrissey, F; Lich, B H

    2006-01-01

    Over the last decade techniques such as confocal light microscopy, in combination with fluorescent labelling, have helped biologists and life scientists to study biological architectures at tissue and cell level in great detail. Meanwhile, obtaining information at very small length scales is possible with the combination of sample preparation techniques and transmission electron microscopy (TEM) or scanning transmission electron microscopy (STEM). Scanning electron microscopy (SEM) is well known for the determination of surface characteristics and morphology. However, the desire to understand the three dimensional relationships of meso-scale hierarchies has led to the development of advanced microscopy techniques, to give a further complementary approach. A focused ion beam (FIB) can be used as a nano-scalpel and hence allows us to reveal internal microstructure in a site-specific manner. Whilst FIB instruments have been used to study and verify the three-dimensional architecture of man made materials, SEM and FIB technologies have now been brought together in a single instrument representing a powerful combination for the study of biological specimens and soft materials. We demonstrate the use of FIB SEM to study three-dimensional relationships for a range of length scales and materials, from small-scale cellular structures to the larger scale interactions between biomedical materials and tissues. FIB cutting of heterogeneous mixtures of hard and soft materials, resulting in a uniform cross-section, has proved to be of particular value since classical preparation methods tend to introduce artefacts. Furthermore, by appropriate selection, we can sequentially cross-section to create a series of 'slices' at specific intervals. 3D reconstruction software can then be used to volume-render information from the 2D slices, enabling us to immediately see the spatial relationships between microstructural components

  12. Critical assessment of the performance of electronic moisture analyzers for small amounts of environmental samples and biological reference materials.

    Science.gov (United States)

    Krachler, M

    2001-12-01

    Two electronic moisture analyzers were critically evaluated with regard to their suitability for determining moisture in small amounts (environmental matrices such as leaves, needles, soil, peat, sediments, and sewage sludge, as well as various biological reference materials. To this end, several homogeneous bulk materials were prepared which were subsequently employed for the development and optimization of all analytical procedures. The key features of the moisture analyzers included a halogen or ceramic heater and an integrated balance with a resolution of 0.1 mg, which is an essential prerequisite for obtaining precise results. Oven drying of the bulk materials in a conventional oven at 105 degrees C until constant mass served as reference method. A heating temperature of 65degrees C was found to provide accurate and precise results for almost all matrices investigated. To further improve the accuracy and precision, other critical parameters such as handling of sample pans, standby temperature, and measurement delay were optimized. Because of its ponderous heating behavior, the performance of the ceramic radiator was inferior to that of the halogen heater, which produced moisture results comparable to those obtained by oven drying. The developed drying procedures were successfully applied to the fast moisture analysis (1.4-6.3 min) of certified biological reference materials of similar provenance to the investigated the bulk materials. Moisture results for 200 mg aliquots ranged from 1.4 to 7.8% and good agreement was obtained between the recommended drying procedure for the reference materials and the electronic moisture analyzers with absolute uncertainties amounting to 0.1% and 0.2-0.3%, respectively.

  13. IAEA biological reference materials

    International Nuclear Information System (INIS)

    Parr, R.M.; Schelenz, R.; Ballestra, S.

    1988-01-01

    The Analytical Quality Control Services programme of the IAEA encompasses a wide variety of intercomparisons and reference materials. This paper reviews only those aspects of the subject having to do with biological reference materials. The 1988 programme foresees 13 new intercomparison exercises, one for major, minor and trace elements, five for radionuclides, and seven for stable isotopes. Twenty-two natural matrix biological reference materials are available: twelve for major, minor and trace elements, six for radionuclides, and four for chlorinated hydrocarbons. Seven new intercomparisons and reference materials are in preparation or under active consideration. Guidelines on the correct use of reference materials are being prepared for publication in 1989 in consultation with other major international producers and users of biological reference materials. The IAEA database on available reference materials is being updated and expanded in scope, and a new publication is planned for 1989. (orig.)

  14. Wireless Biological Electronic Sensors.

    Science.gov (United States)

    Cui, Yue

    2017-10-09

    The development of wireless biological electronic sensors could open up significant advances for both fundamental studies and practical applications in a variety of areas, including medical diagnosis, environmental monitoring, and defense applications. One of the major challenges in the development of wireless bioelectronic sensors is the successful integration of biosensing units and wireless signal transducers. In recent years, there are a few types of wireless communication systems that have been integrated with biosensing systems to construct wireless bioelectronic sensors. To successfully construct wireless biological electronic sensors, there are several interesting questions: What types of biosensing transducers can be used in wireless bioelectronic sensors? What types of wireless systems can be integrated with biosensing transducers to construct wireless bioelectronic sensors? How are the electrical sensing signals generated and transmitted? This review will highlight the early attempts to address these questions in the development of wireless biological electronic sensors.

  15. Dynamic Processes in Biology, Chemistry, and Materials Science: Opportunities for UltraFast Transmission Electron Microscopy - Workshop Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Kabius, Bernd C.; Browning, Nigel D.; Thevuthasan, Suntharampillai; Diehl, Barbara L.; Stach, Eric A.

    2012-07-25

    mission. This workshop built on previous workshops and included three breakout sessions identifying scientific challenges in biology, biogeochemistry, catalysis, and materials science frontier areas of fundamental science that underpin energy and environmental science that would significantly benefit from ultrafast transmission electron microscopy (UTEM). In addition, the current status of time-resolved electron microscopy was examined, and the technologies that will enable future advances in spatio-temporal resolution were identified in a fourth breakout session.

  16. Multiscale Biological Materials

    DEFF Research Database (Denmark)

    Frølich, Simon

    of multiscale biological systems have been investigated and new research methods for automated Rietveld refinement and diffraction scattering computed tomography developed. The composite nature of biological materials was investigated at the atomic scale by looking at the consequences of interactions between...

  17. Electron holography of biological samples.

    Science.gov (United States)

    Simon, P; Lichte, H; Formanek, P; Lehmann, M; Huhle, R; Carrillo-Cabrera, W; Harscher, A; Ehrlich, H

    2008-01-01

    In this paper, we summarise the development of off-axis electron holography on biological samples starting in 1986 with the first results on ferritin from the group of Tonomura. In the middle of the 1990s strong interest was evoked, but then stagnation took place because the results obtained at that stage did not reach the contrast and the resolution achieved by conventional electron microscopy. To date, there exist only a few ( approximately 12) publications on electron holography of biological objects, thus this topic is quite small and concise. The reason for this could be that holography is mostly established in materials science by physicists. Therefore, applications for off-axis holography were powerfully pushed forward in the area of imaging, e.g. electric or magnetic micro- and nanofields. Unstained biological systems investigated by means of off-axis electron holography up to now are ferritin, tobacco mosaic virus, a bacterial flagellum, T5 bacteriophage virus, hexagonal packed intermediate layer of bacteria and the Semliki Forest virus. New results of the authors on collagen fibres and surface layer of bacteria, the so-called S-layer 2D crystal lattice are presented in this review. For the sake of completeness, we will shortly discuss in-line holography of biological samples and off-axis holography of materials related to biological systems, such as biomaterial composites or magnetotactic bacteria.

  18. Wood-derived materials for green electronics, biological Devices, and energy applications

    Science.gov (United States)

    Hongli Zhu; Wei Luo; Peter N. Ciesielski; Zhiqiang Fang; Junyong Zhu; Gunnar Henriksson; Michael E. Himmel; Liangbing Hu

    2016-01-01

    With the arising of global climate change and resource shortage, in recent years, increased attention has been paid to environmentally friendly materials. Trees are sustainable and renewable materials, which give us shelter and oxygen and remove carbon dioxide from the atmosphere. Trees are a primary resource that human society depends upon every day, for example,...

  19. Development of a Free-Electron Laser Center and Research in Medicine, Biology and Materials Science,

    Science.gov (United States)

    1992-05-14

    the reduced electron- larons cause localized distortions in an ionic lattice lattice coupling strength leads to molecule emission, which are... syndrome . Health Science Center at San Antonio and the University Buerger’s disease, palmar hyperhidrosis, frostbite and of Mi.imi School of Medicine, Miami

  20. Novel Aspects of Materials Processing by Ultrafast Lasers: From Electronic to Biological and Cultural Heritage Applications

    International Nuclear Information System (INIS)

    Fotakis, C; Zorba, V; Stratakis, E; Athanassiou, A; Tzanetakis, P; Zergioti, I; Papagoglou, D G; Sambani, K; Filippidis, G; Farsari, M; Pouli, V; Bounos, G; Georgiou, S

    2007-01-01

    Materials processing by ultrafast lasers offers several distinct possibilities for micro/nano scale applications. This is due to the unique characteristics of the laser-matter interactions involved, when sub-picosecond pulses are employed. Prospects arising will be discussed in the context of surface and in bulk laser induced modifications. In particular, examples of diverse applications including the development and functionalization of laser engineered surfaces, the laser transfer of biomolecules and the functionalization of 3D structures constructed by three-photon stereolithography will be presented. Furthermore, the removal of molecular substrates by ultrafast laser ablation will be discussed with emphasis placed on assessing the photochemical changes induced in the remaining bulk material. The results indicate that in femtosecond laser processing of organic materials, besides the well acknowledged morphological advantages, a second fundamental factor responsible for its success pertains to the selective chemical effects. This is crucial for the laser cleaning of sensitive painted artworks

  1. Modern electronic materials

    CERN Document Server

    Watkins, John B

    2013-01-01

    Modern Electronic Materials focuses on the development of electronic components. The book first discusses the history of electronic components, including early developments up to 1900, developments up to World War II, post-war developments, and a comparison of present microelectric techniques. The text takes a look at resistive materials. Topics include resistor requirements, basic properties, evaporated film resistors, thick film resistors, and special resistors. The text examines dielectric materials. Considerations include basic properties, evaporated dielectric materials, ceramic dielectri

  2. Advances in electronic materials

    CERN Document Server

    Kasper, Erich; Grimmeiss, Hermann G

    2008-01-01

    This special-topic volume, Advances in Electronic Materials, covers various fields of materials research such as silicon, silicon-germanium hetero-structures, high-k materials, III-V semiconductor alloys and organic materials, as well as nano-structures for spintronics and photovoltaics. It begins with a brief summary of the formative years of microelectronics; now the keystone of information technology. The latter remains one of the most important global technologies, and is an extremely complex subject-area. Although electronic materials are primarily associated with computers, the internet

  3. Flotation of Biological Materials

    Directory of Open Access Journals (Sweden)

    George Z. Kyzas

    2014-03-01

    Full Text Available Flotation constitutes a gravity separation process, which originated from the minerals processing field. However, it has, nowadays, found several other applications, as for example in the wastewater treatment field. Concerning the necessary bubble generation method, typically dispersed-air or dissolved-air flotation was mainly used. Various types of biological materials were tested and floated efficiently, such as bacteria, fungi, yeasts, activated sludge, grape stalks, etc. Innovative processes have been studied in our Laboratory, particularly for metal ions removal, involving the initial abstraction of heavy metal ions onto a sorbent (including a biosorbent: in the first, the application of a flotation stage followed for the efficient downstream separation of metal-laden particles. The ability of microorganisms to remove metal ions from dilute aqueous solutions (as most wastewaters are is a well-known property. The second separation process, also applied effectively, was a new hybrid cell of microfiltration combined with flotation. Sustainability in this field and its significance for the chemical and process industry is commented.

  4. Peptide π-Electron Conjugates: Organic Electronics for Biology?

    Science.gov (United States)

    Ardoña, Herdeline Ann M; Tovar, John D

    2015-12-16

    Highly ordered arrays of π-conjugated molecules are often viewed as a prerequisite for effective charge-transporting materials. Studies involving these materials have traditionally focused on organic electronic devices, with more recent emphasis on biological systems. In order to facilitate the transition to biological environments, biomolecules that can promote hierarchical ordering and water solubility are often covalently appended to the π-electron unit. This review highlights recent work on π-conjugated systems bound to peptide moieties that exhibit self-assembly and aims to provide an overview on the development and emerging applications of peptide-based supramolecular π-electron systems.

  5. Electronic Materials Science

    Science.gov (United States)

    Irene, Eugene A.

    2005-02-01

    A thorough introduction to fundamental principles and applications From its beginnings in metallurgy and ceramics, materials science now encompasses such high- tech fields as microelectronics, polymers, biomaterials, and nanotechnology. Electronic Materials Science presents the fundamentals of the subject in a detailed fashion for a multidisciplinary audience. Offering a higher-level treatment than an undergraduate textbook provides, this text benefits students and practitioners not only in electronics and optical materials science, but also in additional cutting-edge fields like polymers and biomaterials. Readers with a basic understanding of physical chemistry or physics will appreciate the text's sophisticated presentation of today's materials science. Instructive derivations of important formulae, usually omitted in an introductory text, are included here. This feature offers a useful glimpse into the foundations of how the discipline understands such topics as defects, phase equilibria, and mechanical properties. Additionally, concepts such as reciprocal space, electron energy band theory, and thermodynamics enter the discussion earlier and in a more robust fashion than in other texts. Electronic Materials Science also features: An orientation towards industry and academia drawn from the author's experience in both arenas Information on applications in semiconductors, optoelectronics, photocells, and nanoelectronics Problem sets and important references throughout Flexibility for various pedagogical needs Treating the subject with more depth than any other introductory text, Electronic Materials Science prepares graduate and upper-level undergraduate students for advanced topics in the discipline and gives scientists in associated disciplines a clear review of the field and its leading technologies.

  6. Biological Responses to Materials

    Science.gov (United States)

    Anderson, James M.

    2001-08-01

    All materials intended for application in humans as biomaterials, medical devices, or prostheses undergo tissue responses when implanted into living tissue. This review first describes fundamental aspects of tissue responses to materials, which are commonly described as the tissue response continuum. These actions involve fundamental aspects of tissue responses including injury, inflammatory and wound healing responses, foreign body reactions, and fibrous encapsulation of the biomaterial, medical device, or prosthesis. The second part of this review describes the in vivo evaluation of tissue responses to biomaterials, medical devices, and prostheses to determine intended performance characteristics and safety or biocompatibility considerations. While fundamental aspects of tissue responses to materials are important from research and development perspectives, the in vivo evaluation of tissue responses to these materials is important for performance, safety, and regulatory reasons.

  7. Biological materials: a materials science approach.

    Science.gov (United States)

    Meyers, Marc A; Chen, Po-Yu; Lopez, Maria I; Seki, Yasuaki; Lin, Albert Y M

    2011-07-01

    The approach used by Materials Science and Engineering is revealing new aspects in the structure and properties of biological materials. The integration of advanced characterization, mechanical testing, and modeling methods can rationalize heretofore unexplained aspects of these structures. As an illustration of the power of this methodology, we apply it to biomineralized shells, avian beaks and feathers, and fish scales. We also present a few selected bioinspired applications: Velcro, an Al2O3-PMMA composite inspired by the abalone shell, and synthetic attachment devices inspired by gecko. Copyright © 2010 Elsevier Ltd. All rights reserved.

  8. 37 CFR 1.801 - Biological material.

    Science.gov (United States)

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Biological material. 1.801... Biological Material § 1.801 Biological material. For the purposes of these regulations pertaining to the deposit of biological material for purposes of patents for inventions under 35 U.S.C. 101, the term...

  9. Processing scarce biological samples for light and transmission electron microscopy

    Directory of Open Access Journals (Sweden)

    P Taupin

    2008-06-01

    Full Text Available Light microscopy (LM and transmission electron microscopy (TEM aim at understanding the relationship structure-function. With advances in biology, isolation and purification of scarce populations of cells or subcellular structures may not lead to enough biological material, for processing for LM and TEM. A protocol for preparation of scarce biological samples is presented. It is based on pre-embedding the biological samples, suspensions or pellets, in bovine serum albumin (BSA and bis-acrylamide (BA, cross-linked and polymerized. This preparation provides a simple and reproducible technique to process biological materials, present in limited quantities that can not be amplified, for light and transmission electron microscopy.

  10. Biological effects of nanoparticulate materials

    International Nuclear Information System (INIS)

    Soto, K.F.; Carrasco, A.; Powell, T.G.; Murr, L.E.; Garza, K.M.

    2006-01-01

    A range of morphologically nanoparticulate materials including Ag, NiO, TiO 2 , multiwall carbon nanotubes, and chrysotile asbestos have been characterized by transmission electron microscopy. All but the TiO 2 (anatase and rutile) were observed to exhibit some cytotoxicity at concentrations of 5 μg/ml for a murine macrophage cell line as a respiratory response model. Silver exhibits interesting systemic differences for animal and human toxicity, especially in light of its nanoparticulate materials, and should be avoided even if there is no detectable in vitro cytotoxic response, as a prudent approach to their technological applications

  11. Materials and applications of bioresorbable electronics

    Science.gov (United States)

    Huang, Xian

    2018-01-01

    Bioresorbable electronics is a new type of electronics technology that can potentially lead to biodegradable and dissolvable electronic devices to replace current built-to-last circuits predominantly used in implantable devices and consumer electronics. Such devices dissolve in an aqueous environment in time periods from seconds to months, and generate biological safe products. This paper reviews materials, fabrication techniques, and applications of bioresorbable electronics, and aims to inspire more revolutionary bioresorbable systems that can generate broader social and economic impact. Existing challenges and potential solutions in developing bioresorbable electronics have also been presented to arouse more joint research efforts in this field to build systematic technology framework. Project supported by the National Natural Science Foundation of China (No. 61604108) and the Natural Science Foundation of Tianjin (No. 16JCYBJC40600).

  12. Synaptic electronics: materials, devices and applications.

    Science.gov (United States)

    Kuzum, Duygu; Yu, Shimeng; Wong, H-S Philip

    2013-09-27

    In this paper, the recent progress of synaptic electronics is reviewed. The basics of biological synaptic plasticity and learning are described. The material properties and electrical switching characteristics of a variety of synaptic devices are discussed, with a focus on the use of synaptic devices for neuromorphic or brain-inspired computing. Performance metrics desirable for large-scale implementations of synaptic devices are illustrated. A review of recent work on targeted computing applications with synaptic devices is presented.

  13. Synaptic electronics: materials, devices and applications

    International Nuclear Information System (INIS)

    Kuzum, Duygu; Yu, Shimeng; Philip Wong, H-S

    2013-01-01

    In this paper, the recent progress of synaptic electronics is reviewed. The basics of biological synaptic plasticity and learning are described. The material properties and electrical switching characteristics of a variety of synaptic devices are discussed, with a focus on the use of synaptic devices for neuromorphic or brain-inspired computing. Performance metrics desirable for large-scale implementations of synaptic devices are illustrated. A review of recent work on targeted computing applications with synaptic devices is presented. (topical review)

  14. A living foundry for Synthetic Biological Materials: A synthetic biology roadmap to new advanced materials

    Directory of Open Access Journals (Sweden)

    Rosalind A. Le Feuvre

    2018-06-01

    Full Text Available Society is on the cusp of harnessing recent advances in synthetic biology to discover new bio-based products and routes to their affordable and sustainable manufacture. This is no more evident than in the discovery and manufacture of Synthetic Biological Materials, where synthetic biology has the capacity to usher in a new Materials from Biology era that will revolutionise the discovery and manufacture of innovative synthetic biological materials. These will encompass novel, smart, functionalised and hybrid materials for diverse applications whose discovery and routes to bio-production will be stimulated by the fusion of new technologies positioned across physical, digital and biological spheres. This article, which developed from an international workshop held in Manchester, United Kingdom, in 2017 [1], sets out to identify opportunities in the new materials from biology era. It considers requirements, early understanding and foresight of the challenges faced in delivering a Discovery to Manufacturing Pipeline for synthetic biological materials using synthetic biology approaches. This challenge spans the complete production cycle from intelligent and predictive design, fabrication, evaluation and production of synthetic biological materials to new ways of bringing these products to market. Pathway opportunities are identified that will help foster expertise sharing and infrastructure development to accelerate the delivery of a new generation of synthetic biological materials and the leveraging of existing investments in synthetic biology and advanced materials research to achieve this goal. Keywords: Synthetic biology, Materials, Biological materials, Biomaterials, Advanced materials

  15. Polymer electronic devices and materials.

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, William Kent; Baca, Paul Martin; Dirk, Shawn M.; Anderson, G. Ronald; Wheeler, David Roger

    2006-01-01

    Polymer electronic devices and materials have vast potential for future microsystems and could have many advantages over conventional inorganic semiconductor based systems, including ease of manufacturing, cost, weight, flexibility, and the ability to integrate a wide variety of functions on a single platform. Starting materials and substrates are relatively inexpensive and amenable to mass manufacturing methods. This project attempted to plant the seeds for a new core competency in polymer electronics at Sandia National Laboratories. As part of this effort a wide variety of polymer components and devices, ranging from simple resistors to infrared sensitive devices, were fabricated and characterized. Ink jet printing capabilities were established. In addition to promising results on prototype devices the project highlighted the directions where future investments must be made to establish a viable polymer electronics competency.

  16. [Applications of synthetic biology in materials science].

    Science.gov (United States)

    Zhao, Tianxin; Zhong, Chao

    2017-03-25

    Materials are the basis for human being survival and social development. To keep abreast with the increasing needs from all aspects of human society, there are huge needs in the development of advanced materials as well as high-efficiency but low-cost manufacturing strategies that are both sustainable and tunable. Synthetic biology, a new engineering principle taking gene regulation and engineering design as the core, greatly promotes the development of life sciences. This discipline has also contributed to the development of material sciences and will continuously bring new ideas to future new material design. In this paper, we review recent advances in applications of synthetic biology in material sciences, with the focus on how synthetic biology could enable synthesis of new polymeric biomaterials and inorganic materials, phage display and directed evolution of proteins relevant to materials development, living functional materials, engineered bacteria-regulated artificial photosynthesis system as well as applications of gene circuits for material sciences.

  17. A living foundry for Synthetic Biological Materials: A synthetic biology roadmap to new advanced materials.

    Science.gov (United States)

    Le Feuvre, Rosalind A; Scrutton, Nigel S

    2018-06-01

    Society is on the cusp of harnessing recent advances in synthetic biology to discover new bio-based products and routes to their affordable and sustainable manufacture. This is no more evident than in the discovery and manufacture of Synthetic Biological Materials , where synthetic biology has the capacity to usher in a new Materials from Biology era that will revolutionise the discovery and manufacture of innovative synthetic biological materials. These will encompass novel, smart, functionalised and hybrid materials for diverse applications whose discovery and routes to bio-production will be stimulated by the fusion of new technologies positioned across physical, digital and biological spheres. This article, which developed from an international workshop held in Manchester, United Kingdom, in 2017 [1], sets out to identify opportunities in the new materials from biology era. It considers requirements, early understanding and foresight of the challenges faced in delivering a Discovery to Manufacturing Pipeline for synthetic biological materials using synthetic biology approaches. This challenge spans the complete production cycle from intelligent and predictive design, fabrication, evaluation and production of synthetic biological materials to new ways of bringing these products to market. Pathway opportunities are identified that will help foster expertise sharing and infrastructure development to accelerate the delivery of a new generation of synthetic biological materials and the leveraging of existing investments in synthetic biology and advanced materials research to achieve this goal.

  18. Design of Functional Polyesters for Electronic and Biological Applications

    OpenAIRE

    Nelson, Ashley Marie

    2015-01-01

    Melt polymerization and novel monomers enabled the synthesis of polyesters for electronic and biological applications. Inspiration from nature and a passion for environmental preservation instigated an emphasis on the incorporation of renewable resources into polymeric materials. Critical analysis of current research surrounding bisphenol-A replacements and ioncontaining segmented polyurethanes aided in identifying benchmark polymers, including limitations, challenges, and future needs. Struc...

  19. Magnetically responsive biological materials and their applications

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Pospíšková, K.; Baldíková, E.; Šafaříková, Miroslava

    2016-01-01

    Roč. 7, č. 4 (2016), s. 254-261 ISSN 0976-3961 Institutional support: RVO:60077344 Keywords : adsorbents * biological materials * carriers * magnetic modification * whole-cell biocatalyst Subject RIV: EI - Biotechnology ; Bionics

  20. 75 FR 6348 - Deposit of Biological Materials

    Science.gov (United States)

    2010-02-09

    ... either directly or indirectly. When the invention involves a biological material, sometimes words alone... charge about the same rates for their services. For example, the American Type Culture Collection (ATCC...

  1. Molecular ferroelectrics: where electronics meet biology.

    Science.gov (United States)

    Li, Jiangyu; Liu, Yuanming; Zhang, Yanhang; Cai, Hong-Ling; Xiong, Ren-Gen

    2013-12-28

    In the last several years, we have witnessed significant advances in molecular ferroelectrics, with the ferroelectric properties of molecular crystals approaching those of barium titanate. In addition, ferroelectricity has been observed in biological systems, filling an important missing link in bioelectric phenomena. In this perspective, we will present short historical notes on ferroelectrics, followed by an overview of the fundamentals of ferroelectricity. The latest developments in molecular ferroelectrics and biological ferroelectricity will then be highlighted, and their implications and potential applications will be discussed. We close by noting molecular ferroelectric as an exciting frontier between electronics and biology, and a number of challenges ahead are also described.

  2. Anal Sphincter Augmentation Using Biological Material.

    Science.gov (United States)

    Alam, Nasra N; Narang, Sunil K; Köckerling, Ferdinand; Daniels, Ian R; Smart, Neil J

    2015-01-01

    The aim of this review is to provide an overview of the use of biological materials in the augmentation of the anal sphincter either as part of an overlapping sphincter repair (OSR) or anal bulking procedure. A systematic search of PubMed was conducted using the search terms "anal bulking agents," "anal sphincter repair," or "overlapping sphincter repair." Five studies using biological material as part of an overlapping sphincter repair (OSR) or as an anal bulking agent were identified. 122 patients underwent anal bulking with a biological material. Anorectal physiology was conducted in 27 patients and demonstrated deterioration in maximum resting pressure, and no significant change in maximum squeeze increment. Quality of life scores (QoLs) demonstrated improvements at 6 weeks and 6 months, but this had deteriorated at 12 months of follow up. Biological material was used in 23 patients to carry out an anal encirclement procedure. Improvements in QoLs were observed in patients undergoing OSR as well as anal encirclement using biological material. Incontinence episodes decreased to an average of one per week from 8 to 10 preoperatively. Sphincter encirclement with biological material has demonstrated improvements in continence and QoLs in the short term compared to traditional repair alone. Long-term studies are necessary to determine if this effect is sustained. As an anal bulking agent the benefits are short-term.

  3. Conduit for regeneration of biological material

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a conduit comprising a first material, having 1) a through-going hole, 2) fibers aligned along the long-axis in the through-going hole, each fiber having a diameter in the range 200-2000 nm. The conduit is preferably for regeneration of biological material, even...

  4. Nonlinearity in structural and electronic materials

    International Nuclear Information System (INIS)

    Bishop, A.R.; Beardmore, K.M.; Ben-Naim, E.

    1997-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project strengthens a nonlinear technology base relevant to a variety of problems arising in condensed matter and materials science, and applies this technology to those problems. In this way the controlled synthesis of, and experiments on, novel electronic and structural materials provide an important focus for nonlinear science, while nonlinear techniques help advance the understanding of the scientific principles underlying the control of microstructure and dynamics in complex materials. This research is primarily focused on four topics: (1) materials microstructure: growth and evolution, and porous media; (2) textures in elastic/martensitic materials; (3) electro- and photo-active polymers; and (4) ultrafast photophysics in complex electronic materials. Accomplishments included the following: organization of a ''Nonlinear Materials'' seminar series and international conferences including ''Fracture, Friction and Deformation,'' ''Nonequilibrium Phase Transitions,'' and ''Landscape Paradigms in Physics and Biology''; invited talks at international conference on ''Synthetic Metals,'' ''Quantum Phase Transitions,'' ''1996 CECAM Euroconference,'' and the 1995 Fall Meeting of the Materials Research Society; large-scale simulations and microscopic modeling of nonlinear coherent energy storage at crack tips and sliding interfaces; large-scale simulation and microscopic elasticity theory for precursor microstructure and dynamics at solid-solid diffusionless phase transformations; large-scale simulation of self-assembling organic thin films on inorganic substrates; analysis and simulation of smoothing of rough atomic surfaces; and modeling and analysis of flux pattern formation in equilibrium and nonequilibrium Josephson junction arrays and layered superconductors

  5. Study of biocompatible and biological materials

    CERN Document Server

    Pecheva, Emilia

    2017-01-01

    The book gives an overview on biomineralization, biological, biocompatible and biomimetic materials. It reveals the use of biomaterials alone or in composites, how their performance can be improved by tailoring their surface properties by external factors and how standard surface modification techniques can be applied in the area of biomaterials to beneficially influence their growth on surfaces.

  6. Advanced Materials and Devices for Bioresorbable Electronics.

    Science.gov (United States)

    Kang, Seung-Kyun; Koo, Jahyun; Lee, Yoon Kyeung; Rogers, John A

    2018-05-15

    Recent advances in materials chemistry establish the foundations for unusual classes of electronic systems, characterized by their ability to fully or partially dissolve, disintegrate, or otherwise physically or chemically decompose in a controlled fashion after some defined period of stable operation. Such types of "transient" technologies may enable consumer gadgets that minimize waste streams associated with disposal, implantable sensors that disappear harmlessly in the body, and hardware-secure platforms that prevent unwanted recovery of sensitive data. This second area of opportunity, sometimes referred to as bioresorbable electronics, is of particular interest due to its ability to provide diagnostic or therapeutic function in a manner that can enhance or monitor transient biological processes, such as wound healing, while bypassing risks associated with extended device load on the body or with secondary surgical procedures for removal. Early chemistry research established sets of bioresorbable materials for substrates, encapsulation layers, and dielectrics, along with several options in organic and bio-organic semiconductors. The subsequent realization that nanoscale forms of device-grade monocrystalline silicon, such as silicon nanomembranes (m-Si NMs, or Si NMs) undergo hydrolysis in biofluids to yield biocompatible byproducts over biologically relevant time scales advanced the field by providing immediate routes to high performance operation and versatile, sophisticated levels of function. When combined with bioresorbable conductors, dielectrics, substrates, and encapsulation layers, Si NMs provide the basis for a broad, general class of bioresorbable electronics. Other properties of Si, such as its piezoresistivity and photovoltaic properties, allow other types of bioresorbable devices such as solar cells, strain gauges, pH sensors, and photodetectors. The most advanced bioresorbable devices now exist as complete systems with successful demonstrations of

  7. Scanning probe microscopy in material science and biology

    International Nuclear Information System (INIS)

    Cricenti, A; Colonna, S; Girasole, M; Gori, P; Ronci, F; Longo, G; Dinarelli, S; Luce, M; Rinaldi, M; Ortenzi, M

    2011-01-01

    A review of the activity of scanning probe microscopy at our Institute is presented, going from instrumentation to software development of scanning tunnelling microscopy, atomic force microscopy and scanning near-field optical microscopy (SNOM). Some of the most important experiments in material science and biology performed by our group through the years with these SPM techniques will be presented. Finally, infrared applications by coupling a SNOM with a free electron laser will also be presented.

  8. Quantitative biological measurement in Transmission Electron Tomography

    International Nuclear Information System (INIS)

    Mantell, Judith M; Verkade, Paul; Arkill, Kenton P

    2012-01-01

    It has been known for some time that biological sections shrink in the transmission electron microscope from exposure to the electron beam. This phenomenon is especially important in Electron Tomography (ET). The effect on shrinkage of parameters such as embedding medium or sample type is less well understood. In addition anisotropic area shrinkage has largely been ignored. The intention of this study is to explore the shrinkage on a number of samples ranging in thickness from 200 nm to 500 nm. A protocol was developed to determine the shrinkage in area and thickness using the gold fiducials used in electron tomography. In brief: Using low dose philosophy on the section, a focus area was used prior to a separate virgin study area for a series of known exposures on a tilted sample. The shrinkage was determined by measurements on the gold beads from both sides of the section as determined by a confirmatory tomogram. It was found that the shrinkage in area (approximately to 90-95% of the original) and the thickness (approximately 65% of the original at most) agreed with pervious authors, but that a lmost all the shrinkage was in the first minute and that although the direction of the in-plane shrinkage (in x and y) was sometimes uneven the end result was consistent. It was observed, in general, that thinner samples showed more percentage shrinkage than thicker ones. In conclusion, if direct quantitative measurements are required then the protocol described should be used for all areas studied.

  9. Quantitative biological measurement in Transmission Electron Tomography

    Science.gov (United States)

    Mantell, Judith M.; Verkade, Paul; Arkill, Kenton P.

    2012-07-01

    It has been known for some time that biological sections shrink in the transmission electron microscope from exposure to the electron beam. This phenomenon is especially important in Electron Tomography (ET). The effect on shrinkage of parameters such as embedding medium or sample type is less well understood. In addition anisotropic area shrinkage has largely been ignored. The intention of this study is to explore the shrinkage on a number of samples ranging in thickness from 200 nm to 500 nm. A protocol was developed to determine the shrinkage in area and thickness using the gold fiducials used in electron tomography. In brief: Using low dose philosophy on the section, a focus area was used prior to a separate virgin study area for a series of known exposures on a tilted sample. The shrinkage was determined by measurements on the gold beads from both sides of the section as determined by a confirmatory tomogram. It was found that the shrinkage in area (approximately to 90-95% of the original) and the thickness (approximately 65% of the original at most) agreed with pervious authors, but that a lmost all the shrinkage was in the first minute and that although the direction of the in-plane shrinkage (in x and y) was sometimes uneven the end result was consistent. It was observed, in general, that thinner samples showed more percentage shrinkage than thicker ones. In conclusion, if direct quantitative measurements are required then the protocol described should be used for all areas studied.

  10. NBS activities in biological reference materials

    Energy Technology Data Exchange (ETDEWEB)

    Rasberry, S.D.

    1988-12-01

    NBS activities in biological reference materials during 1986-1988 are described with a preview of plans for future certifications of reference materials. During the period, work has been completed or partially completed on about 40 reference materials of importance to health, nutrition, and environmental quality. Some of the reference materials that have been completed during the period and are described include: creatinine (SRM 914a), bovine serum albumin (SRM 927a), cholesterol in human serum (SRM's 1951-1952), aspartate aminotransferase (RM 8430), cholesterol and fat-soluble vitamins in coconut oil (SRM 1563), wheat flour (SRM 1567a), rice flour (SRM 1568a), mixed diet (RM 8431a), dinitropyrene isomers and 1-nitropyrene (SRM 1596), and complex PAH's from coal tar (SRM 1597). Oyster tissue (SRM 1566a) is being analyzed and should be available in 1988.

  11. Neutron activation analysis of biological material

    International Nuclear Information System (INIS)

    Kucera, J.; Simkova, M.; Obrusnik, I.

    1985-01-01

    The possibilities are briefly summed up of usino. NAA (neutron activation analysis) for determining element traces in foodstuffs and their intake by organisms, for monitoring changes in the content of important trace elements in tissues and body fluids owing to environmental pollution, for verifying the results of other analytical techniques and for certifying the content of element traces in reference materials. Examples are given of the use of NAA, and the results are summed up of the determination of Cd, Mn and Zn in biological reference materials NBS SRM-1577, Bovine Liver, Bowen's Kale, IAEA Milk Powder A-11 and IAEA Animal Muscle H-4. (E.S.)

  12. Electronic, magnetic, and optical materials

    CERN Document Server

    Fulay, Pradeep

    2013-01-01

    Technological aspects of ferroelectric, piezoelectric and pyroelectric materials are discussed in detail, in a way that should allow the reader to select an optimal material for a particular application. The basics of magnetostatics are described clearly, as are a wide range of magnetic properties of materials … .-Tony Harker, Department of Physics and Astronomy, University College London

  13. Ion beam processing of advanced electronic materials

    International Nuclear Information System (INIS)

    Cheung, N.W.; Marwick, A.D.; Roberto, J.B.

    1989-01-01

    This report contains research programs discussed at the materials research society symposia on ion beam processing of advanced electronic materials. Major topics include: shallow implantation and solid-phase epitaxy; damage effects; focused ion beams; MeV implantation; high-dose implantation; implantation in III-V materials and multilayers; and implantation in electronic materials. Individual projects are processed separately for the data bases

  14. High energy electron irradiation of flowable materials

    International Nuclear Information System (INIS)

    Offermann, B.P.

    1975-01-01

    In order to efficiently irradiate a flowable material with high energy electrons, a hollow body is disposed in a container for the material and the material is caused to flow in the form of a thin layer across a surface of the body from or to the interior of the container while the material flowing across the body surface is irradiated. (U.S.)

  15. A routine chromium determination in biological materials; application to various reference materials and standard reference materials

    International Nuclear Information System (INIS)

    Tjioe, P.S.; Goeij, J.J.M. de; Volkers, K.J.

    1979-01-01

    The determination limit under standard working conditions of chromium in biological materials is discussed. Neutron activation analysis and atomic spectrometry have been described for some analytical experiences with NBS SRM 1577 reference material. The chromium determination is a part of a larger multi-element scheme for the determination of 12 elements in biological materials

  16. Electron and Positron Stopping Powers of Materials

    Science.gov (United States)

    SRD 7 NIST Electron and Positron Stopping Powers of Materials (PC database for purchase)   The EPSTAR database provides rapid calculations of stopping powers (collisional, radiative, and total), CSDA ranges, radiation yields and density effect corrections for incident electrons or positrons with kinetic energies from 1 keV to 10 GeV, and for any chemically defined target material.

  17. Biological and chemical sensors based on graphene materials.

    Science.gov (United States)

    Liu, Yuxin; Dong, Xiaochen; Chen, Peng

    2012-03-21

    Owing to their extraordinary electrical, chemical, optical, mechanical and structural properties, graphene and its derivatives have stimulated exploding interests in their sensor applications ever since the first isolation of free-standing graphene sheets in year 2004. This article critically and comprehensively reviews the emerging graphene-based electrochemical sensors, electronic sensors, optical sensors, and nanopore sensors for biological or chemical detection. We emphasize on the underlying detection (or signal transduction) mechanisms, the unique roles and advantages of the used graphene materials. Properties and preparations of different graphene materials, their functionalizations are also comparatively discussed in view of sensor development. Finally, the perspective and current challenges of graphene sensors are outlined (312 references).

  18. Lipid Bilayer Formation on Organic Electronic Materials

    KAUST Repository

    Zhang, Yi

    2018-04-23

    The lipid bilayer is the elemental structure of cell membrane, forming a stable barrier between the interior and exterior of the cell while hosting membrane proteins that enable selective transport of biologically important compounds and cellular recognition. Monitoring the quality and function of lipid bilayers is thus essential and can be performed using electrically active substrates that allow for transduction of signals. Such a promising electronic transducer material is the conducting polymer poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) which has provided a plethora of novel bio transducing architectures. The challenge is however in assembling a bilayer on the conducting polymer surface, which is defect-free and has high mobility. Herein, we investigate the fusion of zwitterionic vesicles on a variety of PEDOT:PSS films, but also on an electron transporting, negatively charged organic semiconductor, in order to understand the surface properties that trigger vesicle fusion. The PEDOT:PSS films are prepared from dispersions containing different concentrations of ethylene glycol included as a formulation additive, which gives a handle to modulate surface physicochemical properties without a compromise on the chemical composition. The strong correlation between the polarity of the surface, the fusion of vesicles and the mobility of the resulting bilayer aides extracting design principles for the development of future conducting polymers that will enable the formation of lipid bilayers.

  19. Nanostructured electronic and magnetic materials

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    and magnetic materials are provided. Advantages of nanocrystalline magnetic mate- rials in the context of ... 2.2 Phosphors for high definition TV. Better resolution of television screens could be ..... materials and that of preparing nanoparticles. This will remain a challenge for the future if nanomaterials are to be competitive.

  20. Environmental testing techniques for electronics and materials

    CERN Document Server

    Dummer, Geoffrey W A; Fry, D W; Higinbotham, W

    2013-01-01

    Environmental Testing Techniques for Electronics and Materials reviews environmental testing techniques for evaluating the performance of electronic equipment, components, and materials. Environmental test planning, test methods, and instrumentation are described, along with the general environmental conditions under which equipment must operate. This book is comprised of 15 chapters and begins by explaining why environmental testing is necessary and describing the environment in which electronics must operate. The next chapter considers how an environmental test plan is designed; the methods

  1. Handling of biological specimens for electron microscopy

    International Nuclear Information System (INIS)

    Bullock, G.

    1987-01-01

    There are many different aspects of specimen preparation procedure which need to be considered in order to achieve good results. Whether using the scanning or transmission microscope, the initial handling procedures are very similar and are selected for the information required. Handling procedures and techniques described are: structural preservation; immuno-and histo-chemistry; x-ray microanalysis and autoradiography; dehydration and embedding; mounting and coating specimens for scanning electron microscopy; and sectioning of resin embedded material. With attention to detail and careful choice of the best available technique, excellent results should be obtainable whatever the specimen. 6 refs

  2. CMOS biomicrosystems where electronics meets biology

    CERN Document Server

    2011-01-01

    "The book will address the-state-of-the-art in integrated Bio-Microsystems that integrate microelectronics with fluidics, photonics, and mechanics. New exciting opportunities in emerging applications that will take system performance beyond offered by traditional CMOS based circuits are discussed in detail. The book is a must for anyone serious about microelectronics integration possibilities for future technologies. The book is written by top notch international experts in industry and academia. The intended audience is practicing engineers with electronics background that want to learn about integrated microsystems. The book will be also used as a recommended reading and supplementary material in graduate course curriculum"--

  3. Mechanical properties of nanostructure of biological materials

    Science.gov (United States)

    Ji, Baohua; Gao, Huajian

    2004-09-01

    Natural biological materials such as bone, teeth and nacre are nanocomposites of protein and mineral with superior strength. It is quite a marvel that nature produces hard and tough materials out of protein as soft as human skin and mineral as brittle as classroom chalk. What are the secrets of nature? Can we learn from this to produce bio-inspired materials in the laboratory? These questions have motivated us to investigate the mechanics of protein-mineral nanocomposite structure. Large aspect ratios and a staggered alignment of mineral platelets are found to be the key factors contributing to the large stiffness of biomaterials. A tension-shear chain (TSC) model of biological nanostructure reveals that the strength of biomaterials hinges upon optimizing the tensile strength of the mineral crystals. As the size of the mineral crystals is reduced to nanoscale, they become insensitive to flaws with strength approaching the theoretical strength of atomic bonds. The optimized tensile strength of mineral crystals thus allows a large amount of fracture energy to be dissipated in protein via shear deformation and consequently enhances the fracture toughness of biocomposites. We derive viscoelastic properties of the protein-mineral nanostructure and show that the toughness of biocomposite can be further enhanced by the viscoelastic properties of protein.

  4. Viscoelastic characterization of soft biological materials

    Science.gov (United States)

    Nayar, Vinod Timothy

    Progressive and irreversible retinal diseases are among the primary causes of blindness in the United States, attacking the cells in the eye that transform environmental light into neural signals for the optic pathway. Medical implants designed to restore visual function to afflicted patients can cause mechanical stress and ultimately damage to the host tissues. Research shows that an accurate understanding of the mechanical properties of the biological tissues can reduce damage and lead to designs with improved safety and efficacy. Prior studies on the mechanical properties of biological tissues show characterization of these materials can be affected by environmental, length-scale, time, mounting, stiffness, size, viscoelastic, and methodological conditions. Using porcine sclera tissue, the effects of environmental, time, and mounting conditions are evaluated when using nanoindentation. Quasi-static tests are used to measure reduced modulus during extended exposure to phosphate-buffered saline (PBS), as well as the chemical and mechanical analysis of mounting the sample to a solid substrate using cyanoacrylate. The less destructive nature of nanoindentation tests allows for variance of tests within a single sample to be compared to the variance between samples. The results indicate that the environmental, time, and mounting conditions can be controlled for using modified nanoindentation procedures for biological samples and are in line with averages modulus values from previous studies but with increased precision. By using the quasi-static and dynamic characterization capabilities of the nanoindentation setup, the additional stiffness and viscoelastic variables are measured. Different quasi-static control methods were evaluated along with maximum load parameters and produced no significant difference in reported reduced modulus values. Dynamic characterization tests varied frequency and quasi-static load, showing that the agar could be modeled as a linearly

  5. Rapid homogenisation and drying of biological materials

    International Nuclear Information System (INIS)

    Donev, I.Y.

    1977-01-01

    In connection with the implementation for detection of trace elements in the pathogenesis of Ischaemic Heart Diseases and for the work of the laboratory a small apparatus for homogenisation and drying biological materials at liquid nitrogen temperature was constructed. For a complete drying 4 to 6 hours are necessary. A laboratory assistant of average qualification can do the work for 13 homogenisates in about 8-9 hours. The capacity of the homogeniser is about 1.5x10 -5 m 3 . Preliminary investigations were carried out for the determination of differences at drying. (T.G.)

  6. Materials, Processes, and Facile Manufacturing for Bioresorbable Electronics: A Review.

    Science.gov (United States)

    Yu, Xiaowei; Shou, Wan; Mahajan, Bikram K; Huang, Xian; Pan, Heng

    2018-05-07

    Bioresorbable electronics refer to a new class of advanced electronics that can completely dissolve or disintegrate with environmentally and biologically benign byproducts in water and biofluids. They have provided a solution to the growing electronic waste problem with applications in temporary usage of electronics such as implantable devices and environmental sensors. Bioresorbable materials such as biodegradable polymers, dissolvable conductors, semiconductors, and dielectrics are extensively studied, enabling massive progress of bioresorbable electronic devices. Processing and patterning of these materials are predominantly relying on vacuum-based fabrication methods so far. However, for the purpose of commercialization, nonvacuum, low-cost, and facile manufacturing/printing approaches are the need of the hour. Bioresorbable electronic materials are generally more chemically reactive than conventional electronic materials, which require particular attention in developing the low-cost manufacturing processes in ambient environment. This review focuses on material reactivity, ink availability, printability, and process compatibility for facile manufacturing of bioresorbable electronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Biological and environmental reference materials in CENAM.

    Science.gov (United States)

    Arvizu-Torres, R; Perez-Castorena, A; Salas-Tellez, J A; Mitani-Nakanishi, Y

    2001-06-01

    Since 1994, when the NIST/NOAA Quality Assurance Program in Chemical Measurements was discussed in Queretaro, CENAM, the National Measurement Institute (NMI) of Mexico, has become involved in the development of reference materials. In the field of biological and environmental reference materials, in particular, the NORAMET collaboration program with NIST and NRC, and the North-American Environmental Cooperation signed among three free-trade treaty organizations, have greatly helped the development of the materials metrology program in the newly established CENAM. This paper describes some particularly significant efforts of CENAM in the development of biological and environmental reference materials, on the basis of inter-comparison studies organized with local and governmental environmental agencies of Mexico. In the field of water pollution CENAM has developed a practical proficiency testing (PT) scheme for field laboratories, as a part of registration by local government in the metropolitan area, according to the Mexican Ecological Regulation. The results from these eight PTs in the last 5 years have demonstrated that this scheme has helped ensure the reliability of analytical capability of more than 50 field laboratories in three states, Mexico, D.F., and the States of Mexico and Queretaro. Similar experience has been obtained for more than 70 service units of stack emission measurements in the three states in 1998 and 1999, as a result of the design of a PT scheme for reference gas mixtures. This PT scheme has been accomplished successfully by 30 analytical laboratories who provide monitoring services and perform research on toxic substances (Hg, methylmercury, PCB, etc.) in Mexico. To support these activities, reference samples have been produced through the NIST SRMs, and efforts have been made to increase CENAM's capability in the preparation of primary reference materials in spectrometric solutions and gas mixtures. Collaboration among NMIs has also

  8. Noncovalent Interactions in Organic Electronic Materials

    KAUST Repository

    Ravva, Mahesh Kumar

    2017-06-29

    In this chapter, we provide an overview of how noncovalent interactions, determined by the chemical structure of π-conjugated molecules and polymers, govern essential aspects of the electronic, optical, and mechanical characteristics of organic semiconductors. We begin by describing general aspects of materials design, including the wide variety of chemistries exploited to control the electronic and optical properties of these materials. We then discuss explicit examples of how the study of noncovalent interactions can provide deeper chemical insights that can improve the design of new generations of organic electronic materials.

  9. Solid freeform fabrication of biological materials

    Science.gov (United States)

    Wang, Jiwen

    This thesis investigates solid freeform fabrication of biological materials for dental restoration and orthopedic implant applications. The basic approach in this study for solid freeform fabrication of biological materials is micro-extrusion of single or multiple slurries for 3D components and inkjet color printing of multiple suspensions for functionally graded materials (FGMs). Common issues associated with micro-extrusion and inkjet color printing are investigated. These common issues include (i) formulation of stable slurries with a pseudoplastic property, (ii) cross-sectional geometry of the extrudate as a function of the extrusion parameters, (iii) fabrication path optimization for extrusion process, (iv) extrusion optimization for multi-layer components, (v) composition control in functionally graded materials, and (vi) sintering optimization to convert the freeform fabricated powder compact to a dense body for biological applications. The present study clearly shows that the rheological and extrusion behavior of dental porcelain slurries depend strongly on the pH value of the slurry and extrusion conditions. A slurry with pseudoplastic properties is a basic requirement for obtaining extruded lines with rectangular cross-sections. The cross-sectional geometry of the extrudate is also strongly affected by extrusion parameters including the extrusion nozzle height, nozzle moving speed, extrusion rate, and critical nozzle height. Proper combinations of these extrusion parameters are necessary in order to obtain single line extrudates with near rectangular cross-sections and 3D objects with dimensional accuracy, uniform wall thickness, good wall uprightness, and no wall slumping. Based on these understandings, single-wall, multi-wall, and solid teeth have been fabricated via micro-extrusion of the dental slurry directly from a CAD digital model in 30 min. Inkjet color printing using stable Al2O3 and ZrO 2 aqueous suspensions has been developed to fabricate

  10. Surfaces and interfaces of electronic materials

    CERN Document Server

    Brillson, Leonard J

    2012-01-01

    An advanced level textbook covering geometric, chemical, and electronic structure of electronic materials, and their applications to devices based on semiconductor surfaces, metal-semiconductor interfaces, and semiconductor heterojunctions. Starting with the fundamentals of electrical measurements on semiconductor interfaces, it then describes the importance of controlling macroscopic electrical properties by atomic-scale techniques. Subsequent chapters present the wide range of surface and interface techniques available to characterize electronic, optical, chemical, and structural propertie

  11. Using electron beams to investigate catalytic materials

    International Nuclear Information System (INIS)

    Zhang, Bingsen; Su, Dang Sheng

    2014-01-01

    Transmission Electron microscopy (TEM) enables us, not only to reveal the morphology, but also to provide structural, chemical and electronic information about solid catalysts at the atomic level, providing a dramatic driving force for the development of heterogeneous catalysis. Almost all catalytic materials have been studied with TEM in order to obtain information about their structures, which can help us to establish the synthesis-structure-property relationships and to design catalysts with new structures and desired properties. Herein, several examples will be reviewed to illustrate the investigation of catalytic materials by using electron beams. (authors)

  12. Transparent oxide electronics from materials to devices

    CERN Document Server

    Martins, Rodrigo; Barquinha, Pedro; Pereira, Luis

    2012-01-01

    Transparent electronics is emerging as one of the most promising technologies for the next generation of electronic products, away from the traditional silicon technology. It is essential for touch display panels, solar cells, LEDs and antistatic coatings. The book describes the concept of transparent electronics, passive and active oxide semiconductors, multicomponent dielectrics and their importance for a new era of novel electronic materials and products. This is followed by a short history of transistors, and how oxides have revolutionized this field. It concludes with a glance at lo

  13. Biological reference materials and analysis of toxic elements

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, R; Sukumar, A

    1988-12-01

    Biological monitoring of toxic metal pollution in the environment requires quality control analysis with use of standard reference materials. A variety of biological tissues are increasingly used for analysis of element bioaccumulation, but the available Certified Reference Materials (CRMs) are insufficient. An attempt is made to review the studies made using biological reference materials for animal and human tissues. The need to have inter-laboratory studies and CRM in the field of biological monitoring of toxic metals is also discussed.

  14. Electron Transfer in Chemistry and Biology - The Primary Events in ...

    Indian Academy of Sciences (India)

    transfers, occurs in a cascade in many biological processes, including photosynthesis. ... the model reactions of photosynthetic ... biological relevance. GENERAL I ARTICLE of electrons, respectively. This has entirely changed the earlier framework of interpreting reactions in chemistry and biology. This shift in emphasis ...

  15. Transmission Electron Microscopy and Diffractometry of Materials

    CERN Document Server

    Fultz, Brent

    2013-01-01

    This book explains concepts of transmission electron microscopy (TEM) and x-ray diffractometry (XRD) that are important for the characterization of materials. The fourth edition adds important new techniques of TEM such as electron tomography, nanobeam diffraction, and geometric phase analysis. A new chapter on neutron scattering completes the trio of x-ray, electron and neutron diffraction. All chapters were updated and revised for clarity. The book explains the fundamentals of how waves and wavefunctions interact with atoms in solids, and the similarities and differences of using x-rays, electrons, or neutrons for diffraction measurements. Diffraction effects of crystalline order, defects, and disorder in materials are explained in detail. Both practical and theoretical issues are covered. The book can be used in an introductory-level or advanced-level course, since sections are identified by difficulty. Each chapter includes a set of problems to illustrate principles, and the extensive Appendix includes la...

  16. Quantifying electron transfer reactions in biological systems

    DEFF Research Database (Denmark)

    Sjulstok, Emil Sjulstok; Olsen, Jógvan Magnus Haugaard; Solov'yov, Ilia A

    2015-01-01

    which for example occur in photosynthesis, cellular respiration, DNA repair, and possibly magnetic field sensing. Quantum biology uses computation to model biological interactions in light of quantum mechanical effects and has primarily developed over the past decade as a result of convergence between...

  17. Advanced Electron Microscopy in Materials Physics

    International Nuclear Information System (INIS)

    Zhu, Y.; Jarausch, K.

    2009-01-01

    Aberration correction has opened a new frontier in electron microscopy by overcoming the limitations of conventional round lenses, providing sub-angstrom-sized probes and extending information limits. The imaging and analytical performance of these corrector-equipped microscopes affords an unprecedented opportunity to study structure-property relationships of matter at the atomic scale. This new generation of microscopes is able to retrieve high-quality structural information comparable to neutron and synchrotron x-ray experiments, but with local atomic resolution. These advances in instrumentation are accelerating the research and development of various functional materials ranging from those for energy generation, conversion, transportation and storage to those for catalysis and nano-device applications. The dramatic improvements in electron-beam illumination and detection also present a host of new challenges for the interpretation and optimization of experiments. During 7-9 November 2007, a workshop, entitled 'Aberration Corrected Electron Microscopy in Material Physics', was convened at the Center for Functional Nanomaterials, Brookhaven National Laboratories (BNL) to address these opportunities and challenges. The workshop was co-sponsored by Hitachi High Technologies, a leader in electron microscopy instrumentation, and BNL's Institute of Advanced Electron Microscopy, a leader in materials physics research using electron microscopy. The workshop featured presentations by internationally prominent scientists working at the frontiers of electron microscopy, both on developing instrumentation and applying it in materials physics. The meeting, structured to stimulate scientific exchanges and explore new capabilities, brought together ∼100 people from over 10 countries. This special issue complies many of the advances in instrument performance and materials physics reported by the invited speakers and attendees at the workshop.

  18. Runaway-electron-materials interaction studies

    International Nuclear Information System (INIS)

    Bolt, H.; Miyahara, A.

    1990-03-01

    During the operation of magnetic fusion devices it has been frequently observed that runaway electrons can cause severe damage to plasma facing components. The energy of the runaway electrons could possibly reach several 100 MeV in a next generation device with an energy content in the plasma in the order of 100 MJ. In this study effects of high energy electron - materials interaction were determined by laboratory experiments using particle beam facilities, i.e. the Electron Linear Accelerator of the Institute of Scientific and Industrial Research of Osaka University and the 10 MW Neutral Beam Injection Test Stand of the National Institute for Fusion Science. The experiments and further analyses lead to a first assessment of the damage thresholds of plasma facing materials and components under runaway electron impact. It was found that metals (stainless steel, molybdenum, tungsten) showed grain growth, crack formation and/or melting already below the threshold for crack initiation on graphite (14-33 MJ/m 2 ). Strong erosion of carbon materials would occur above 100 MJ/m 2 . Damage to metal coolant channels can occur already below an energy deposition of 100 MJ/m 2 . The energy deposited in the metal coolant channels depends on the thickness of the plasma facing carbon material D, with the shielding efficiency S of carbon approximately as S∼D 1.15 . (author) 304 refs. 12 tabs. 59 figs

  19. Dielectric materials electrization by fast electrons

    International Nuclear Information System (INIS)

    Dyrkov, V.A.; Kononov, B.A.

    1990-01-01

    Electrization of short-circuited high-ohmage targets under irradiation by 50-200 keV electrons non-uniformly by volume is investigated both experimentally and theoretically. The obtained data show that effect of space charge field increases monotonically up to stationary state during irradiation. Time constant for space charge accumulation constitutes 1-10 min and has lower value for polymethylmethacrylate as compared with polyethyleneterephthalate and decreases with increase of beam current density. Good agreement of experimental and theoretical results for both materials confirms the validity of main positions of phonomenological model of space charge formation in dielectric materials under fast electron irradiation

  20. Sustainable Materials Management (SMM) Electronics Challenge Data

    Science.gov (United States)

    On September 22, 2012, EPA launched the SMM Electronics Challenge. The Challenge encourages electronics manufacturers, brand owners and retailers to strive to send 100 percent of the used electronics they collect from the public, businesses and within their own organizations to third-party certified electronics refurbishers and recyclers. The Challenge??s goals are to: 1). Ensure responsible recycling through the use of third-party certified recyclers, 2). Increase transparency and accountability through public posting of electronics collection and recycling data, and 3). Encourage outstanding performance through awards and recognition. By striving to send 100 percent of used electronics collected to certified recyclers and refurbishers, Challenge participants are ensuring that the used electronics they collect will be responsibly managed by recyclers that maximize reuse and recycling, minimize exposure to human health and the environment, ensure the safe management of materials by downstream handlers, and require destruction of all data on used electronics. Electronics Challenge participants are publicly recognized on EPA's website as a registrant, new participant, or active participant. Awards are offered in two categories - tier and champion. Tier awards are given in recognition of achieving all the requirements under a gold, silver or bronze tier. Champion awards are given in two categories - product and non-product. For champion awards, a product is an it

  1. Progress in molecular precursors for electronic materials

    Energy Technology Data Exchange (ETDEWEB)

    Buhro, W.E. [Washington Univ., St. Louis, MO (United States)

    1996-09-01

    Molecular-precursor chemistry provides an essential underpinning to all electronic-materials technologies, including photovoltaics and related areas of direct interest to the DOE. Materials synthesis and processing is a rapidly developing field in which advances in molecular precursors are playing a major role. This article surveys selected recent research examples that define the exciting current directions in molecular-precursor science. These directions include growth of increasingly complex structures and stoichiometries, surface-selective growth, kinetic growth of metastable materials, growth of size-controlled quantum dots and quantum-dot arrays, and growth at progressively lower temperatures. Continued progress in molecular-precursor chemistry will afford precise control over the crystal structures, nanostructures, and microstructures of electronic materials.

  2. Computational Nanotechnology Molecular Electronics, Materials and Machines

    Science.gov (United States)

    Srivastava, Deepak; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    This presentation covers research being performed on computational nanotechnology, carbon nanotubes and fullerenes at the NASA Ames Research Center. Topics cover include: nanomechanics of nanomaterials, nanotubes and composite materials, molecular electronics with nanotube junctions, kinky chemistry, and nanotechnology for solid-state quantum computers using fullerenes.

  3. Biological applications of ultraviolet free-electron lasers

    International Nuclear Information System (INIS)

    Sutherland, J.C.

    1997-10-01

    This review examines the possibilities for biological research using the three ultraviolet free-electron lasers that are nearing operational status in the US. The projected operating characteristics of major interest in biological research of the free-electron lasers at Brookhaven National Laboratory, the Thomas Jefferson National Accelerator Facility, and Duke University are presented. Experimental applications in the areas of far- and vacuum ultraviolet photophysics and photochemistry, structural biology, environmental photobiology, and medical research are discussed and the prospects for advances in these areas, based upon the characteristics of the new ultraviolet free-electron lasers, are evaluated

  4. Electronic Structure of Strongly Correlated Materials

    CERN Document Server

    Anisimov, Vladimir

    2010-01-01

    Electronic structure and physical properties of strongly correlated materials containing elements with partially filled 3d, 4d, 4f and 5f electronic shells is analyzed by Dynamical Mean-Field Theory (DMFT). DMFT is the most universal and effective tool used for the theoretical investigation of electronic states with strong correlation effects. In the present book the basics of the method are given and its application to various material classes is shown. The book is aimed at a broad readership: theoretical physicists and experimentalists studying strongly correlated systems. It also serves as a handbook for students and all those who want to be acquainted with fast developing filed of condensed matter physics.

  5. Electronic Transport in Two-Dimensional Materials

    Science.gov (United States)

    Sangwan, Vinod K.; Hersam, Mark C.

    2018-04-01

    Two-dimensional (2D) materials have captured the attention of the scientific community due to the wide range of unique properties at nanometer-scale thicknesses. While significant exploratory research in 2D materials has been achieved, the understanding of 2D electronic transport and carrier dynamics remains in a nascent stage. Furthermore, because prior review articles have provided general overviews of 2D materials or specifically focused on charge transport in graphene, here we instead highlight charge transport mechanisms in post-graphene 2D materials, with particular emphasis on transition metal dichalcogenides and black phosphorus. For these systems, we delineate the intricacies of electronic transport, including band structure control with thickness and external fields, valley polarization, scattering mechanisms, electrical contacts, and doping. In addition, electronic interactions between 2D materials are considered in the form of van der Waals heterojunctions and composite films. This review concludes with a perspective on the most promising future directions in this fast-evolving field.

  6. Interactions of electrons with biologically important molecules

    International Nuclear Information System (INIS)

    Pisklova, K.; Papp, P.; Stano, M.

    2012-01-01

    For the study of interactions of low-energy electrons with the molecules in the gas phase, the authors used electron-molecule cross-beam apparatus. The experiment is carried out in high vacuum, where molecules of the tested compound are inducted through a capillary. For purposes of this experiment the sample was electrically heated to 180 Deg C., giving a bundle of GlyGly molecules into the gas phase. The resulting signals can be evaluated in two different modes: mass spectrum - at continuous electron energy (e.g. 100 eV) they obtained the signal of intensity of the ions according to their mass to charge ratio; ionization and resonance spectra - for selected ion mass when the authors received the signal of intensity of the ions, depending on the energy of interacting electron.

  7. Photoemission for f-electron materials

    International Nuclear Information System (INIS)

    Huang, Youngsea.

    1989-01-01

    The dissertation investigates the interpretation of photoemission from f-electron materials. The authors also discuss unusual room temperature solid-state reactions in Yb-Cu films that they discovered. They show the importance of considering the entire system in the photoemission process and that photoemission actually measures the energy difference between total energies of the initial state and the final excited state of the whole system. They point out misconceptions in the current interpretation of photoemission from mixed valent materials. Their results on Yb-Cu system and other high-resolution photoemission measurements on mixed valent Yb-based materials show that the 4f feature is not pinned at the Fermi level though there is a 4f 14 (6s5d) 2 and 4f 13 (6s5d) 3 configuration degeneracy in the ground state. They suggest that this non-pinning is a general phenomenon due to the fact that the final state is not completely relaxed in the photoemission process. They discuss the current competing models of photoemission from Ce-based materials and show problems with their interpretations. As 4f electrons are more itinerant for Ce and Yb, they give a delocalized-localized kind of interpretation for 4f levels of Ce based materials. They employ the Ce-Yb analogy (electron-hole inversion and thereby an energy scale inversion) with the impurity model to photoemission from Yb-based materials and point out contradictory results on YbAl 3 in the literature. In their results on the Yb-Cu system, where the Yb valence varies from ∼3 to ∼2.2, they do not observe the Kondo resonance within the limits of their experimental resolution. They suggest that to date no Kondo resonance has been observed, and speculate either that the impurity model is inadequate for Yb-based materials or that photoemission is unable to detect a Kondo resonance

  8. Laser interaction with biological material mathematical modeling

    CERN Document Server

    Kulikov, Kirill

    2014-01-01

    This book covers the principles of laser interaction with biological cells and tissues of varying degrees of organization. The problems of biomedical diagnostics are considered. Scattering of laser irradiation of blood cells is modeled for biological structures (dermis, epidermis, vascular plexus). An analytic theory is provided which is based on solving the wave equation for the electromagnetic field. It allows the accurate analysis of interference effects arising from the partial superposition of scattered waves. Treated topics of mathematical modeling are: optical characterization of biological tissue with large-scale and small-scale inhomogeneities in the layers, heating blood vessel under laser irradiation incident on the outer surface of the skin and thermo-chemical denaturation of biological structures at the example of human skin.

  9. Laser-matter structuration of optical and biological materials

    Energy Technology Data Exchange (ETDEWEB)

    Hallo, L., E-mail: hallo@celia.u-bordeaux1.fr [CELIA, Universite Bordeaux 1 (France); Mezel, C., E-mail: candice.mezel@cea.fr [CELIA, Universite Bordeaux 1 (France); CEA Le Ripault, 37260 Monts (France); Guillemot, F., E-mail: fabien.guillemot@inserm.fr [UMR 577 INSERM, Universite Bordeaux 2 (France); Chimier, B., E-mail: chimier@celia.u-bordeaux1.fr [CELIA, Universite Bordeaux 1 (France); Bourgeade, A., E-mail: antoine.bourgeade@cea.fr [CEA-CESTA, Le Barp (France); Regan, C., E-mail: regan@celia.u-bordeaux1.fr [CELIA, Universite Bordeaux 1 (France); Duchateau, G., E-mail: duchateau@celia.u-bordeaux1.fr [CELIA, Universite Bordeaux 1 (France); Souquet, A., E-mail: agnes.souquet@inserm.fr [UMR 577 INSERM, Universite Bordeaux 2 (France); Hebert, D., E-mail: david.hebert@cea.fr [CEA-CESTA, Le Barp (France)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer In this study we model nanomaterial structuring. Black-Right-Pointing-Pointer The laser energy deposition is discussed first. Black-Right-Pointing-Pointer Full and approximate models are discussed. Black-Right-Pointing-Pointer Dynamic material response is addressed via hydrodynamics. Black-Right-Pointing-Pointer Sild effects are accounted for - Abstract: Interaction of ultrafast laser, i.e. from the femtosecond (fs) to the nanosecond (ns) regime, with initially transparent matter may produce very high energy density hot spots in the bulk as well as at the material surface, depending on focusing conditions. In the fs regime, absorption is due to ionisation of the dielectric, which enables absorption process to begin, and then hydrodynamic to take place. In the ns regime both absorption and hydrodynamic are coupled to each other, which complexifies considerably the comprehension but matter structuration looks similar. A numerical tool including solution of 3D Maxwell equations and a rate equation for free electrons is first compared to some available simple models of laser energy absorption. Then, subsequent material deformation, i.e. structuration, is determined by solving hydrodynamic equations, including or not solid behaviour. We show that nature of the final structures strongly depends on the amount of deposited energy and on the shape of the absorption zone. Then we address some problems related to laser-matter structuration of optical and biological materials in the fs, ps and ns regimes.

  10. [Synthetic biology and rearrangements of microbial genetic material].

    Science.gov (United States)

    Liang, Quan-Feng; Wang, Qian; Qi, Qing-Sheng

    2011-10-01

    As an emerging discipline, synthetic biology has shown great scientific values and application prospects. Although there have been many reviews of various aspects on synthetic biology over the last years, this article, for the first time, attempted to discuss the relationship and difference between microbial genetics and synthetic biology. We summarized the recent development of synthetic biology in rearranging microbial genetic materials, including synthesis, design and reduction of genetic materials, standardization of genetic parts and modularization of genetic circuits. The relationship between synthetic biology and microbial genetic engineering was also discussed in the paper.

  11. Quantum effects in biological electron transfer

    Czech Academy of Sciences Publication Activity Database

    de la Lande, A.; Babcock, N. S.; Řezáč, Jan; Levy, B.; Sanders, B. C.; Salahub, D.

    2012-01-01

    Roč. 14, č. 17 (2012), s. 5902-5918 ISSN 1463-9076 Institutional research plan: CEZ:AV0Z40550506 Keywords : electron transfer * tunnelling * decoherence * semi-classical molecular dynamics * density functional theory Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.829, year: 2012

  12. Connecting Biology to Electronics: Molecular Communication via Redox Modality.

    Science.gov (United States)

    Liu, Yi; Li, Jinyang; Tschirhart, Tanya; Terrell, Jessica L; Kim, Eunkyoung; Tsao, Chen-Yu; Kelly, Deanna L; Bentley, William E; Payne, Gregory F

    2017-12-01

    Biology and electronics are both expert at for accessing, analyzing, and responding to information. Biology uses ions, small molecules, and macromolecules to receive, analyze, store, and transmit information, whereas electronic devices receive input in the form of electromagnetic radiation, process the information using electrons, and then transmit output as electromagnetic waves. Generating the capabilities to connect biology-electronic modalities offers exciting opportunities to shape the future of biosensors, point-of-care medicine, and wearable/implantable devices. Redox reactions offer unique opportunities for bio-device communication that spans the molecular modalities of biology and electrical modality of devices. Here, an approach to search for redox information through an interactive electrochemical probing that is analogous to sonar is adopted. The capabilities of this approach to access global chemical information as well as information of specific redox-active chemical entities are illustrated using recent examples. An example of the use of synthetic biology to recognize external molecular information, process this information through intracellular signal transduction pathways, and generate output responses that can be detected by electrical modalities is also provided. Finally, exciting results in the use of redox reactions to actuate biology are provided to illustrate that synthetic biology offers the potential to guide biological response through electrical cues. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Bright field electron microscopy of biological specimens

    International Nuclear Information System (INIS)

    Johansen, B.V.

    1976-01-01

    A preirradiation procedure is described which preserves negatively stained morphological features in bright field electron micrographs to a resolution of about 1.2 nm. Prior to microscopy the pre-irradiation dose (1.6 x 10 -3 C cm -2 ) is given at low electron optical magnification at five different areas on the grid (the centre plus four 'corners'). This pre-irradiation can be measured either with a Faraday cage or through controlled exposure-developing conditions. Uranyl formate stained T2 bacteriophages and stacked disk aggregates of Tobacco Mosaic Virus (TMV) protein served as test objects. A comparative study was performed on specimens using either the pre-irradiation procedure or direct irradiation by the 'minimum beam exposure' technique. Changes in the electron diffraction pattern of the stain-protein complex and the disappearance of certain morphological features in the specimens were both used in order to compare the pre-irradiation method with the direct exposure technique. After identical electron exposures the pre-irradiation approach gave a far better preservation of specimen morphology. Consequently this procedure gives the microscopist more time to select and focus appropriate areas for imaging before deteriorations take place. The investigation also suggested that microscopy should be carried out between 60,000 and 100,000 times magnification. Within this magnification range, it is possible to take advantage of the phase contrast transfer characteristics of the objective lens while the electron load on the object is kept at a moderate level. Using the pre-irradiation procedure special features of the T2 bacteriophage morphology could be established. (author)

  14. Polymeric materials obtained by electron beam irradiation

    International Nuclear Information System (INIS)

    Dragusin, M.; Moraru, R.; Martin, D.; Radoiu, M.; Marghitu, S.; Oproiu, C.

    1995-01-01

    Research activities in the field of electron beam irradiation of monomer aqueous solution to produce polymeric materials used for waste waters treatment, agriculture and medicine are presented. The technologies and special features of these polymeric materials are also described. The influence of the chemical composition of the solution to ba irradiated, absorbed dose level and absorbed dose rate level are discussed. Two kinds of polyelectrolytes, PA and PV types and three kinds of hydrogels, pAAm, pAAmNa and pNaAc types, the production of which was first developed with IETI-10000 Co-60 source and then adapted to the linacs built in Accelerator Laboratory, are described. (author)

  15. Electron microscopy of nanostructured semiconductor materials

    International Nuclear Information System (INIS)

    Neumann, Wolfgang

    2003-01-01

    For various material systems of low dimensions, including multilayers, islands, and quantum dots, the potential applicability of transmission electron microscopy (TEM) is demonstrated. Conventional TEM is applied to elucidate size, shape, and arrangement of nanostructures, whereas high-resolution imaging is used for visualizing their atomic structure. In addition, microchemical peculiarities of the nanoscopic objects are investigated by analytical TEM techniques (energy-filtered TEM, energy-dispersive X-ray spectroscopy)

  16. Effective atomic numbers and electron density of dosimetric material

    Directory of Open Access Journals (Sweden)

    Kaginelli S

    2009-01-01

    Full Text Available A novel method for determination of mass attenuation coefficient of x-rays employing NaI (Tl detector system and radioactive sources is described.in this paper. A rigid geometry arrangement and gating of the spectrometer at FWHM position and selection of absorber foils are all done following detailed investigation, to minimize the effect of small angle scattering and multiple scattering on the mass attenuation coefficient, m/r, value. Firstly, for standardization purposes the mass attenuation coefficients of elemental foils such as Aluminum, Copper, Molybdenum, Tantalum and Lead are measured and then, this method is utilized for dosimetric interested material (sulfates. The experimental mass attenuation coefficient values are compared with the theoretical values to find good agreement between the theory and experiment within one to two per cent. The effective atomic numbers of the biological substitute material are calculated by sum rule and from the graph. The electron density of dosimetric material is calculated using the effective atomic number. The study has discussed in detail the attenuation coefficient, effective atomic number and electron density of dosimetric material/biological substitutes.

  17. Topological materials discovery using electron filling constraints

    Science.gov (United States)

    Chen, Ru; Po, Hoi Chun; Neaton, Jeffrey B.; Vishwanath, Ashvin

    2018-01-01

    Nodal semimetals are classes of topological materials that have nodal-point or nodal-line Fermi surfaces, which give them novel transport and topological properties. Despite being highly sought after, there are currently very few experimental realizations, and identifying new materials candidates has mainly relied on exhaustive database searches. Here we show how recent studies on the interplay between electron filling and nonsymmorphic space-group symmetries can guide the search for filling-enforced nodal semimetals. We recast the previously derived constraints on the allowed band-insulator fillings in any space group into a new form, which enables effective screening of materials candidates based solely on their space group, electron count in the formula unit, and multiplicity of the formula unit. This criterion greatly reduces the computation load for discovering topological materials in a database of previously synthesized compounds. As a demonstration, we focus on a few selected nonsymmorphic space groups which are predicted to host filling-enforced Dirac semimetals. Of the more than 30,000 entires listed, our filling criterion alone eliminates 96% of the entries before they are passed on for further analysis. We discover a handful of candidates from this guided search; among them, the monoclinic crystal Ca2Pt2Ga is particularly promising.

  18. Electron beam melting of bearing materials

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmied, G.; Schuler, A. (Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Elektrotechnik); Elsinger, G.; Koroschetz, F. (MIBA Gleitlager AG, Laakirchen (Austria)); Tschegg, E.K. (Technische Univ., Vienna (Austria). Inst. fuer Angewandte und Technische Physik)

    1990-06-01

    This paper reports on a surface treatment method for the bearing materials AlSn6 which permits the use of this material without the overlay usually required. Microstructural refinement is achieved by means of a surface melting technique using an electron beam with successive rapid solidification. Extremely fine tin precipitates are formed in the melted surface layer which lead to significantly better tribological properties of the bearing material. Tests compared the tribological properties for AlSn6 bearings treated by the surface melting technique with those of untreated bearings. Whereas all untreated bearings failed by seizure after only 2 h of testing, 30% of the tested bearings which had been surface melted survived the entire testing program without damage.

  19. Materiomics: biological protein materials, from nano to macro

    Science.gov (United States)

    Cranford, Steven; Buehler, Markus J

    2010-01-01

    Materiomics is an emerging field of science that provides a basis for multiscale material system characterization, inspired in part by natural, for example, protein-based materials. Here we outline the scope and explain the motivation of the field of materiomics, as well as demonstrate the benefits of a materiomic approach in the understanding of biological and natural materials as well as in the design of de novo materials. We discuss recent studies that exemplify the impact of materiomics – discovering Nature’s complexity through a materials science approach that merges concepts of material and structure throughout all scales and incorporates feedback loops that facilitate sensing and resulting structural changes at multiple scales. The development and application of materiomics is illustrated for the specific case of protein-based materials, which constitute the building blocks of a variety of biological systems such as tendon, bone, skin, spider silk, cells, and tissue, as well as natural composite material systems (a combination of protein-based and inorganic constituents) such as nacre and mollusk shells, and other natural multiscale systems such as cellulose-based plant and wood materials. An important trait of these materials is that they display distinctive hierarchical structures across multiple scales, where molecular details are exhibited in macroscale mechanical responses. Protein materials are intriguing examples of materials that balance multiple tasks, representing some of the most sustainable material solutions that integrate structure and function despite severe limitations in the quality and quantity of material building blocks. However, up until now, our attempts to analyze and replicate Nature’s materials have been hindered by our lack of fundamental understanding of these materials’ intricate hierarchical structures, scale-bridging mechanisms, and complex material components that bestow protein-based materials their unique properties

  20. Ab initio electronic stopping power in materials

    International Nuclear Information System (INIS)

    Shukri, Abdullah-Atef

    2015-01-01

    The average energy loss of an ion per unit path length when it is moving through the matter is named the stopping power. The knowledge of the stopping power is essential for a variety of contemporary applications which depend on the transport of ions in matter, especially ion beam analysis techniques and ion implantation. Most noticeably, the use of proton or heavier ion beams in radiotherapy requires the knowledge of the stopping power. Whereas experimental data are readily available for elemental solids, the data are much more scarce for compounds. The linear response dielectric formalism has been widely used in the past to study the electronic stopping power. In particular, the famous pioneering calculations due to Lindhard evaluate the electronic stopping power of a free electron gas. In this thesis, we develop a fully ab initio scheme based on linear response time-dependent density functional theory to predict the impact parameter averaged quantity named the random electronic stopping power (RESP) of materials without any empirical fitting. The purpose is to be capable of predicting the outcome of experiments without any knowledge of target material besides its crystallographic structure. Our developments have been done within the open source ab initio code named ABINIT, where two approximations are now available: the Random-Phase Approximation (RPA) and the Adiabatic Local Density Approximation (ALDA). Furthermore, a new method named 'extrapolation scheme' have been introduced to overcome the stringent convergence issues we have encountered. These convergence issues have prevented the previous studies in literature from offering a direct comparison to experiment. First of all, we demonstrate the importance of describing the realistic ab initio electronic structure by comparing with the historical Lindhard stopping power evaluation. Whereas the Lindhard stopping power provides a first order description that captures the general features of the

  1. Material science lesson from the biological photosystem.

    Science.gov (United States)

    Kim, Younghye; Lee, Jun Ho; Ha, Heonjin; Im, Sang Won; Nam, Ki Tae

    2016-01-01

    Inspired by photosynthesis, artificial systems for a sustainable energy supply are being designed. Each sequential energy conversion process from light to biomass in natural photosynthesis is a valuable model for an energy collection, transport and conversion system. Notwithstanding the numerous lessons of nature that provide inspiration for new developments, the features of natural photosynthesis need to be reengineered to meet man's demands. This review describes recent strategies toward adapting key lessons from natural photosynthesis to artificial systems. We focus on the underlying material science in photosynthesis that combines photosystems as pivotal functional materials and a range of materials into an integrated system. Finally, a perspective on the future development of photosynthesis mimetic energy systems is proposed.

  2. Physics of electronic materials principles and applications

    CERN Document Server

    Rammer, Jorgen

    2017-01-01

    Adopting a uniquely pedagogical approach, this comprehensive textbook on the quantum mechanics of semiconductor materials and devices focuses on the materials, components and devices themselves whilst incorporating a substantial amount of fundamental physics related to condensed matter theory and quantum mechanics. Written primarily for advanced undergraduate students in physics and engineering, this book can also be used as a supporting text for introductory quantum mechanics courses, and will be of interest to anyone interested in how electronic devices function at a fundamental level. Complete with numerous exercises, and with all the necessary mathematics and physics included in appendices, this book guides the reader seamlessly through the principles of quantum mechanics and the quantum theory of metals and semiconductors, before describing in detail how devices are exploited within electric circuits and in the hardware of computers, for example as amplifiers, switches and transistors. Includes nume...

  3. Transmission electron microscopy and diffractometry of materials

    CERN Document Server

    Fultz, Brent

    2001-01-01

    This book teaches graduate students the concepts of trans- mission electron microscopy (TEM) and x-ray diffractometry (XRD) that are important for the characterization of materi- als. It emphasizes themes common to both techniques, such as scattering from atoms and the formation and analysis of dif- fraction patterns. It also describes unique aspects of each technique, especially imaging and spectroscopy in the TEM. The textbook thoroughly develops both introductory and ad- vanced-level material, using over 400 accompanying illustra- tions. Problems are provided at the end of each chapter to reinforce key concepts. Simple citatioins of rules are avoi- ded as much as possible, and both practical and theoretical issues are explained in detail. The book can be used as both an introductory and advanced-level graduate text since sec- tions/chapters are sorted according to difficulty and grou- ped for use in quarter and semester courses on TEM and XRD.

  4. Structural and functional biological materials: Abalone nacre, sharp materials, and abalone foot adhesion

    Science.gov (United States)

    Lin, Albert Yu-Min

    A three-part study of lessons from nature is presented through the examination of various biological materials, with an emphasis on materials from the mollusk Haliotis rufescens, commonly referred to as the red abalone. The three categories presented are: structural hierarchy, self-assembly, and functionality. Ocean mollusk shells are composed of aragonite/calcite crystals interleaved with layers of a visco-elastic protein, having dense, tailored structures with excellent mechanical properties. The complex nano-laminate structure of this bio-composite material is characterized and related to its mechanical properties. Three levels of structural hierarchy are identified: macroscale mesolayers separating larger regions of tiled aragonite, microscale organization of 0.5 mum by 10 mum aragonite bricks; nanoscale mineral bridges passing through 30 nm layers of organic matrix separating individual aragonite tiles. Composition and growth mechanisms of this nanostructure were observed through close examination of laboratory-grown samples using scanning electron microscopy (SEM), Raman spectroscopy, and transmission electron microscopy (TEM). Glass slides and nacre pucks were implanted onto the growth surface of living abalone and removed periodically to observe trends in nacre deposition. Various deproteinization and demineralization experiments are used to explore the inorganic and organic components of the nacre's structure. The organic component of the shell is characterized by atomic force microscopy (AFM). The functionality of various biological materials is described and investigated. Two specific types of functionality are characterized, the ability of some materials to cut and puncture through sharp designs, and the ability for some materials to be used as attachment devices. Aspects of cutting materials employed by a broad range of animals were characterized and compared. In respect to the attachment mechanisms the foot of the abalone and the tree frog were

  5. Delayed Luminescence and Biophotons from Biological Materials

    Science.gov (United States)

    Knoesel, Ernst; Hann, Patrick; Garzon, Maria; Pfeiffer, Erik; Lofland, Samuel

    2008-03-01

    There has recently been increased interest in the field of biophotonics, since it is a non-invasive technique. Many biological systems, such as yeast, bacteria, leaves, seeds, and algae display the unusual phenomenon of a weak, delayed luminescence on the timescale of seconds to minutes after transient illumination. It is also observed that the time decay of the biophotonic emission is not exponential, even after the delay, and that there can be oscillations in intensity with time, which depend on the duration of the illumination. Results from two types of yeast, i.e. bread yeast, and saccharomyces, as well as those from several types of algae are presented. Possible mechanisms for the source of the ultraweak photon emission are discussed.

  6. Validation of tritium measurements in biological materials

    International Nuclear Information System (INIS)

    Kim, M.A.; Baumgartner, F.

    1988-01-01

    The maximum deviation of experimental R value from its real value, which is defined as the ratio of tissue bound to tissue water tritium, has been calculated and verified experimentally by taking consideration of isotopic fractionation arised in the course of water separation. Experimental procedures examined for the purpose are the azeotropic distillation and lyophilization for the removal of tissue water and the oxidative combustion of organic residue either by thermal process or by low temperature plasma generation. Each procedure optimalized by obviating or correcting isotope effects as well as other sources of error has been tested with mixed standards and biological samples. By washing out the exchangeable tritium and also physically bound tritium, the precision and accuracy of R values are further improved

  7. 2. Brazilian Congress on Cell Biology and 7. Brazilian Colloquium on Electron Microscopy - Abstracts

    International Nuclear Information System (INIS)

    1980-01-01

    Immunology, virology, bacteriology, genetics and protozoology are some of the subjects treated in the 2. Brazilian Congress on Cell Biology. Studies using radioisotopic techniques and ultrastructural cytological studies are presented. Use of optical - and electron microscopy in some of these studies is discussed. In the 7. Brazilian Colloquium on Electron Microscopy, the application of this technique to materials science is discussed (failure analysis in metallurgy, energy dispersion X-ray analysis, etc). (I.C.R.) [pt

  8. Analytical Chemistry at the Interface Between Materials Science and Biology

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Janese C. [Iowa State Univ., Ames, IA (United States)

    2000-09-21

    Likedlessentid sciences, anal~cd chetis~continues toreinvent itself. Moving beyond its traditional roles of identification and quantification, analytical chemistry is now expanding its frontiers into areas previously reserved to other disciplines. This work describes several research efforts that lie at the new interfaces between analytical chemistry and two of these disciplines, namely materials science and biology. In the materials science realm, the search for new materials that may have useful or unique chromatographic properties motivated the synthesis and characterization of electrically conductive sol-gels. In the biology realm, the search for new surface fabrication schemes that would permit or even improve the detection of specific biological reactions motivated the design of miniaturized biological arrays. Collectively, this work represents some of analytical chemistry’s newest forays into these disciplines. The introduction section to this dissertation provides a literature review on several of the key aspects of this work. In advance of the materials science discussion, a brief introduction into electrochemically-modulated liquid chromatography (EMLC) and sol-gel chemistry is provided. In advance of the biological discussions, brief overviews of scanning force microscopy (SFM) and the oxidative chemistry used to construct our biological arrays are provided. This section is followed by four chapters, each of which is presented as a separate manuscript, and focuses on work that describes some of our cross-disciplinary efforts within materials science and biology. This dissertation concludes with a general summary and future prospectus.

  9. AC Calorimetric Design for Dynamic of Biological Materials

    OpenAIRE

    Shigeo Imaizumi

    2006-01-01

    We developed a new AC calorimeter for the measurement of dynamic specific heat capacity in liquids, including aqueous suspensions of biological materials. This method has several advantages. The first is that a high-resolution measurement of heat capacity, inmillidegrees, can be performed as a function of temperature, even with a very small sample. Therefore, AC calorimeter is a powerful tool to study critical behavior a tphase transition in biological materials. The second advantage is that ...

  10. Sustainable Materials Management (SMM) Electronics Challenge

    Science.gov (United States)

    Learn how the SMM Electronics Challenge encourage electronic manufacturers to strive to send 100 percent of the used electronics they collect from the public and retailers to certified electronics refurbishers and recyclers.

  11. THE DEVELOPMENT OF BIOLOGY MATERIAL RESOURCES BY METACOGNITIVE STRATEGY

    Directory of Open Access Journals (Sweden)

    Endang Susantini

    2016-02-01

    Full Text Available The Development of Biology Material Resources by Metacognitive Strategy The study was aimed at finding out the suitability of Biology Materials using the metacognitive strategy. The materials were textbooks, self-understanding Evaluation Sheet and the key, lesson plan, and tests including the answer key. The criteria of appropriateness included the relevance of the resources with the content validity, face va­lidity and the language. This research and development study was carried out employing a 3D model, namely define, design and develop. At the define stage, three topics were selected for analysis, they were virus, Endocrine System, and Genetic material. During the design phase, the physical appearance of the materials was suited with the Metacognitive Strategy. At the develop phase, the material resources were examined and validated by two Biology experts and senior teachers of Biology. The results showed that the Biology material Resources using Metacognitive Strategy developed in the study has fell into the category of very good ( score > 3.31 and was therefore considered suitable.

  12. Electron spin interactions in chemistry and biology fundamentals, methods, reactions mechanisms, magnetic phenomena, structure investigation

    CERN Document Server

    Likhtenshtein, Gertz

    2016-01-01

    This book presents the versatile and pivotal role of electron spin interactions in nature. It provides the background, methodologies and tools for basic areas related to spin interactions, such as spin chemistry and biology, electron transfer, light energy conversion, photochemistry, radical reactions, magneto-chemistry and magneto-biology. The book also includes an overview of designing advanced magnetic materials, optical and spintronic devices and photo catalysts. This monograph appeals to scientists and graduate students working in the areas related to spin interactions physics, biophysics, chemistry and chemical engineering.

  13. Quantitative Scanning Transmission Electron Microscopy of Electronic and Nanostructured Materials

    Science.gov (United States)

    Yankovich, Andrew B.

    Electronic and nanostructured materials have been investigated using advanced scanning transmission electron microscopy (STEM) techniques. The first topic is the microstructure of Ga and Sb-doped ZnO. Ga-doped ZnO is a candidate transparent conducting oxide material. The microstructure of GZO thin films grown by MBE under different growth conditions and different substrates were examined using various electron microscopy (EM) techniques. The microstructure, prevalent defects, and polarity in these films strongly depend on the growth conditions and substrate. Sb-doped ZnO nanowires have been shown to be the first route to stable p-type ZnO. Using Z-contrast STEM, I have showed that an unusual microstructure of Sb-decorated head-to-head inversion domain boundaries and internal voids contain all the Sb in the nanowires and cause the p-type conduction. InGaN thin films and InGaN / GaN quantum wells (QW) for light emitting diodes are the second topic. Low-dose Z-contrast STEM, PACBED, and EDS on InGaN QW LED structures grown by MOCVD show no evidence for nanoscale composition variations, contradicting previous reports. In addition, a new extended defect in GaN and InGaN was discovered. The defect consists of a faceted pyramid-shaped void that produces a threading dislocation along the [0001] growth direction, and is likely caused by carbon contamination during growth. Non-rigid registration (NRR) and high-precision STEM of nanoparticles is the final topic. NRR is a new image processing technique that corrects distortions arising from the serial nature of STEM acquisition that previously limited the precision of locating atomic columns and counting the number of atoms in images. NRR was used to demonstrate sub-picometer precision in STEM images of single crystal Si and GaN, the best achieved in EM. NRR was used to measure the atomic surface structure of Pt nanoacatalysts and Au nanoparticles, which revealed new bond length variation phenomenon of surface atoms. In

  14. Materiomics: biological protein materials, from nano to macro

    Directory of Open Access Journals (Sweden)

    Steven Cranford

    2010-11-01

    Full Text Available Steven Cranford, Markus J BuehlerCenter for Materials Science and Engineering, Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USAAbstract: Materiomics is an emerging field of science that provides a basis for multiscale material system characterization, inspired in part by natural, for example, protein-based materials. Here we outline the scope and explain the motivation of the field of materiomics, as well as demonstrate the benefits of a materiomic approach in the understanding of biological and natural materials as well as in the design of de novo materials. We discuss recent studies that exemplify the impact of materiomics – discovering Nature’s complexity through a materials science approach that merges concepts of material and structure throughout all scales and incorporates feedback loops that facilitate sensing and resulting structural changes at multiple scales. The development and application of materiomics is illustrated for the specific case of protein-based materials, which constitute the building blocks of a variety of biological systems such as tendon, bone, skin, spider silk, cells, and tissue, as well as natural composite material systems (a combination of protein-based and inorganic constituents such as nacre and mollusk shells, and other natural multiscale systems such as cellulose-based plant and wood materials. An important trait of these materials is that they display distinctive hierarchical structures across multiple scales, where molecular details are exhibited in macroscale mechanical responses. Protein materials are intriguing examples of materials that balance multiple tasks, representing some of the most sustainable material solutions that integrate structure and function despite severe limitations in the quality and quantity of material building blocks. However, up until now, our attempts to analyze and

  15. Some examples of utilization of electron paramagnetic resonance in biology

    International Nuclear Information System (INIS)

    Bemski, G.

    1982-10-01

    A short outline of the fundamentals of electron paramagnetic resonance (EPR) is presented and is followed by examples of the application of EPR to biology. These include use of spin labels, as well as of ENDOR principally to problems of heme proteins, photosynthesis and lipids. (Author) [pt

  16. Electron Transfer in Chemistry and Biology – The Primary Events

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 12. Electron Transfer in Chemistry and Biology – The Primary Events in Photosynthesis. V Krishnan. General Article Volume 2 Issue 12 December 1997 pp 77-86. Fulltext. Click here to view fulltext PDF. Permanent link:

  17. Advancing Small Satellite Electronics Heritage for Microfluidic Biological Experiments

    Science.gov (United States)

    White, Bruce; Mazmanian, Edward; Tapio, Eric

    2016-01-01

    DLR's Eu:CROPIS (Euglena and Combined Regenerative Organic-Food Production in Space) mission, launching in 2017, will carry multiple biological payloads into a sun-synchronous orbit, including NASA Ames' PowerCell experiment. PowerCell will attempt to characterize the viability of synthetic biology at micro-g, Lunar, and Martian gravity levels. PowerCell experiment requirements demand an electronic system similar to previous microfluidic biology payloads, but with an expanded feature set. As such, the system was based on PharmaSat (Diaz-Aguado et al. 2009), a previous successful biology payload from NASA Ames, and improved upon. Newer, more miniaturized electronics allow for greater capability with a lower part count and smaller size. Two identical PowerCell enclosures will fly. Each enclosure contains two separate and identical experiments with a 48-segment optical density measurement system, grow light system, microfluidic system for nutrient delivery and waste flushing, plus thermal control and environmental sensing/housekeeping including temperature, pressure, humidity, and acceleration. Electronics consist of a single Master PCB that interfaces to the spacecraft bus and regulates power and communication, plus LED, Detector, and Valve Manifold PCBs for each experiment. To facilitate ease of reuse on future missions, experiment electronics were designed to be compatible with a standard 3U small sat form factor and power bus, or to interface with a Master power/comm PCB for use in a larger satellite as in the case of PowerCell's flight on Eu:CROPIS.

  18. Moessbauer spectroscopic studies of magnetically ordered biological materials

    International Nuclear Information System (INIS)

    Dickson, D.P.E.

    1987-01-01

    This paper discusses recent work showing the application of Moessbauer spectroscopy to the study of the properties of the magnetically ordered materials which occur in a variety of biological systems. These materials display a diversity of behaviour which provides good examples of the various possibilities which can arise with iron-containing particles of different compositions and sizes. (orig.)

  19. Biomaterials-based electronics: polymers and interfaces for biology and medicine.

    Science.gov (United States)

    Muskovich, Meredith; Bettinger, Christopher J

    2012-05-01

    Advanced polymeric biomaterials continue to serve as a cornerstone for new medical technologies and therapies. The vast majority of these materials, both natural and synthetic, interact with biological matter in the absence of direct electronic communication. However, biological systems have evolved to synthesize and utilize naturally-derived materials for the generation and modulation of electrical potentials, voltage gradients, and ion flows. Bioelectric phenomena can be translated into potent signaling cues for intra- and inter-cellular communication. These cues can serve as a gateway to link synthetic devices with biological systems. This progress report will provide an update on advances in the application of electronically active biomaterials for use in organic electronics and bio-interfaces. Specific focus will be granted to covering technologies where natural and synthetic biological materials serve as integral components such as thin film electronics, in vitro cell culture models, and implantable medical devices. Future perspectives and emerging challenges will also be highlighted. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Advances in cryo-electron tomography for biology and medicine.

    Science.gov (United States)

    Koning, Roman I; Koster, Abraham J; Sharp, Thomas H

    2018-05-01

    Cryo-electron tomography (CET) utilizes a combination of specimen cryo-fixation and multi-angle electron microscopy imaging to produce three-dimensional (3D) volume reconstructions of native-state macromolecular and subcellular biological structures with nanometer-scale resolution. In recent years, cryo-electron microscopy (cryoEM) has experienced a dramatic increase in the attainable resolution of 3D reconstructions, resulting from technical improvements of electron microscopes, improved detector sensitivity, the implementation of phase plates, automated data acquisition schemes, and improved image reconstruction software and hardware. These developments also greatly increased the usability and applicability of CET as a diagnostic and research tool, which is now enabling structural biologists to determine the structure of proteins in their native cellular environment to sub-nanometer resolution. These recent technical developments have stimulated us to update on our previous review (Koning, R.I., Koster, A.J., 2009. Cryo-electron tomography in biology and medicine. Ann Anat 191, 427-445) in which we described the fundamentals of CET. In this follow-up, we extend this basic description in order to explain the aforementioned recent advances, and describe related 3D techniques that can be applied to the anatomy of biological systems that are relevant for medicine. Copyright © 2018 Elsevier GmbH. All rights reserved.

  1. Epitaxial Graphene: A New Material for Electronics

    Science.gov (United States)

    de Heer, Walt A.

    2007-10-01

    Graphene multilayers are grown epitaxially on single crystal silicon carbide. This system is composed of several graphene layers of which the first layer is electron doped due to the built-in electric field and the other layers are essentially undoped. Unlike graphite the charge carriers show Dirac particle properties (i.e. an anomalous Berry's phase, weak anti-localization and square root field dependence of the Landau level energies). Epitaxial graphene shows quasi-ballistic transport and long coherence lengths; properties that may persists above cryogenic temperatures. Paradoxically, in contrast to exfoliated graphene, the quantum Hall effect is not observed in high mobility epitaxial graphene. It appears that the effect is suppressed due to absence of localized states in the bulk of the material. Epitaxial graphene can be patterned using standard lithography methods and characterized using a wide array of techniques. These favorable features indicate that interconnected room temperature ballistic devices may be feasible for low dissipation high-speed nano-electronics.

  2. Nanomechanical strength mechanisms of hierarchical biological materials and tissues.

    Science.gov (United States)

    Buehler, Markus J; Ackbarow, Theodor

    2008-12-01

    Biological protein materials (BPMs), intriguing hierarchical structures formed by assembly of chemical building blocks, are crucial for critical functions of life. The structural details of BPMs are fascinating: They represent a combination of universally found motifs such as alpha-helices or beta-sheets with highly adapted protein structures such as cytoskeletal networks or spider silk nanocomposites. BPMs combine properties like strength and robustness, self-healing ability, adaptability, changeability, evolvability and others into multi-functional materials at a level unmatched in synthetic materials. The ability to achieve these properties depends critically on the particular traits of these materials, first and foremost their hierarchical architecture and seamless integration of material and structure, from nano to macro. Here, we provide a brief review of this field and outline new research directions, along with a review of recent research results in the development of structure-property relationships of biological protein materials exemplified in a study of vimentin intermediate filaments.

  3. Advances in superconducting materials and electronics technologies

    International Nuclear Information System (INIS)

    Palmer, D.N.

    1990-01-01

    Technological barriers blocking the early implementation of ceramic oxide high critical temperature [Tc] and LHe Nb based superconductors are slowly being dismantled. Spearheading these advances are mechanical engineers with diverse specialties and creative interests. As the technology expands, most engineers have recognized the importance of inter-disciplinary cooperation. Cooperation between mechanical engineers and material and system engineers is of particular importance. Recently, several problems previously though to be insurmountable, has been successfully resolved. These accomplishment were aided by interaction with other scientists and practitioners, working in the superconductor research and industrial communities, struggling with similar systems and materials problems. Papers published here and presented at the 1990 ASME Winter Annual Meeting held in Dallas, Texas 25-30 November 1990 can be used as a bellwether to gauge the progress in the development of both ceramic oxide and low temperature Nb superconducting device and system technologies. Topics are focused into two areas: mechanical behavior of high temperature superconductors and thermal and mechanical problems in superconducting electronics

  4. Ordered materials for organic electronics and photonics.

    Science.gov (United States)

    O'Neill, Mary; Kelly, Stephen M

    2011-02-01

    We present a critical review of semiconducting/light emitting, liquid crystalline materials and their use in electronic and photonic devices such as transistors, photovoltaics, OLEDs and lasers. We report that annealing from the mesophase improves the order and packing of organic semiconductors to produce state-of-the-art transistors. We discuss theoretical models which predict how charge transport and light emission is affected by the liquid crystalline phase. Organic photovoltaics and OLEDs require optimization of both charge transport and optical properties and we identify the various trade-offs involved for ordered materials. We report the crosslinking of reactive mesogens to give pixellated full-colour OLEDs and distributed bi-layer photovoltaics. We show how the molecular organization inherent to the mesophase can control the polarization of light-emitting devices and the gain in organic, thin-film lasers and can also provide distributed feedback in chiral nematic mirrorless lasers. We update progress on the surface alignment of liquid crystalline semiconductors to obtain monodomain devices without defects or devices with spatially varying properties. Finally the significance of all of these developments is assessed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Oxide bipolar electronics: materials, devices and circuits

    International Nuclear Information System (INIS)

    Grundmann, Marius; Klüpfel, Fabian; Karsthof, Robert; Schlupp, Peter; Schein, Friedrich-Leonhard; Splith, Daniel; Yang, Chang; Bitter, Sofie; Von Wenckstern, Holger

    2016-01-01

    We present the history of, and the latest progress in, the field of bipolar oxide thin film devices. As such we consider primarily pn-junctions in which at least one of the materials is a metal oxide semiconductor. A wide range of n-type and p-type oxides has been explored for the formation of such bipolar diodes. Since most oxide semiconductors are unipolar, challenges and opportunities exist with regard to the formation of heterojunction diodes and band lineups. Recently, various approaches have led to devices with high rectification, namely p-type ZnCo 2 O 4 and NiO on n-type ZnO and amorphous zinc-tin-oxide. Subsequent bipolar devices and applications such as photodetectors, solar cells, junction field-effect transistors and integrated circuits like inverters and ring oscillators are discussed. The tremendous progress shows that bipolar oxide electronics has evolved from the exploration of various materials and heterostructures to the demonstration of functioning integrated circuits. Therefore a viable, facile and high performance technology is ready for further exploitation and performance optimization. (topical review)

  6. Profile of accidents with biological material at a dental school

    Directory of Open Access Journals (Sweden)

    Sandra Aragão de Almeida Sasamoto

    2014-09-01

    Full Text Available http://dx.doi.org/10.4025/actascihealthsci.v36i1.14976 Current research characterizes the epidemiological profile of accidents with biological material (BM that occurred in a government-run dental school and identifies the post-exposure behavior taken by the injured subjects. The cross-sectional retrospective study comprises professors, students and technical-administration personnel who worked in the laboratory from 2001 to 2008 (n = 566. An electronic questionnaire, prepared by software developed for this purpose, was sent to subjects between May and August 2008 for data collection. Ninety-one (34.2% out of 266 participants reported some type of exposure to BM. There was no difference between the occurrence of accidents according to the subjects’ category (p = 0.496 and sex (p = 0.261. Most of the subjects reported cutaneous exposure (76.9% comprising saliva (68.1% and blood (48.3%. The fingers were the body members most affected. Accidents occurred mostly during clinical (34.1% and surgical (30.8% procedures. Although the use of protection equipments was high (82.9%, only 26.4% of subjects reported the accident and only 28.6% sought immediate help. Most of the injured subjects failed to report the accidents and did not comply with the guidelines. Others trivialized basic behavior such as the interruption of the procedure to seek medical assistance.

  7. Electron Beam Welding of Thick Copper Material

    Energy Technology Data Exchange (ETDEWEB)

    Broemssen, Bernt von [IVF Industriforskning och utveckling AB, Stockholm (Sweden)

    2002-08-01

    The purpose of this study was to review the two variants of the Electron Beam Welding (EBW) processes developed (or used) by 1- SKB, Sweden with assistance from TWI, England and 2 - POSIVA, Finland with assistance from Outokumpu, Finland. The aim was also to explain the principle properties of the EBW method: how it works, the parameters controlling the welding result but also giving rise to benefits, and differences between the EBW variants. The main conclusions are that both SKB and POSIVA will within a few years succeed to qualify their respective EBW method for welding of copper canisters. The Reduced Pressure EBW that SKB use today seems to be very promising in order to avoid root defects. If POSIVA does not succeed to avoid root defects with the high vacuum method and the beam oscillation technique it should be possible for POSIVA to incorporate the Reduced Pressure technique albeit with significant changes to the EBW equipment. POSIVA has possibly an advantage over SKB with the beam oscillation technique used, which gives an extra degree of freedom to affect the weld quality. The beam oscillation could be of importance for closing of the keyhole. Before EBW of lids, the material certification showing the alloy content (specifying min and max impurity percentages) and the mechanical properties should be checked. The welded material needs also to be tested for mechanical properties. If possible the weld should have a toughness level equal to that of the unwelded parent material. Specifically some conclusions are reported regarding the SKB equipment. Suggestions for further development are also given in the conclusion chapter.

  8. Electron Beam Welding of Thick Copper Material

    International Nuclear Information System (INIS)

    Broemssen, Bernt von

    2002-08-01

    The purpose of this study was to review the two variants of the Electron Beam Welding (EBW) processes developed (or used) by 1- SKB, Sweden with assistance from TWI, England and 2 - POSIVA, Finland with assistance from Outokumpu, Finland. The aim was also to explain the principle properties of the EBW method: how it works, the parameters controlling the welding result but also giving rise to benefits, and differences between the EBW variants. The main conclusions are that both SKB and POSIVA will within a few years succeed to qualify their respective EBW method for welding of copper canisters. The Reduced Pressure EBW that SKB use today seems to be very promising in order to avoid root defects. If POSIVA does not succeed to avoid root defects with the high vacuum method and the beam oscillation technique it should be possible for POSIVA to incorporate the Reduced Pressure technique albeit with significant changes to the EBW equipment. POSIVA has possibly an advantage over SKB with the beam oscillation technique used, which gives an extra degree of freedom to affect the weld quality. The beam oscillation could be of importance for closing of the keyhole. Before EBW of lids, the material certification showing the alloy content (specifying min and max impurity percentages) and the mechanical properties should be checked. The welded material needs also to be tested for mechanical properties. If possible the weld should have a toughness level equal to that of the unwelded parent material. Specifically some conclusions are reported regarding the SKB equipment. Suggestions for further development are also given in the conclusion chapter

  9. Occupational accidents involving biological material among public health workers.

    Science.gov (United States)

    Chiodi, Mônica Bonagamba; Marziale, Maria Helena Palucci; Robazzi, Maria Lúcia do Carmo Cruz

    2007-01-01

    This descriptive research aimed to recognize the occurrence of work accidents (WA) involving exposure to biological material among health workers at Public Health Units in Ribeirão Preto-SP, Brazil. A quantitative approach was adopted. In 2004, 155 accidents were notified by means of the Work Accident Communication (WAC). Sixty-two accidents (40%) involved exposure to biological material that could cause infections like Hepatitis and Aids. The highest number of victims (42 accidents) came from the category of nursing aids and technicians. Needles were responsible for 80.6% of accidents and blood was the biological material involved in a majority of occupational exposure cases. This subject needs greater attention, so that prevention measures can be implemented, which consider the peculiarities of the activities carried out by the different professional categories.

  10. Materials Manufactured from 3D Printed Synthetic Biology Arrays

    Science.gov (United States)

    Gentry, Diana; Micks, Ashley

    2013-01-01

    Many complex, biologically-derived materials have extremely useful properties (think wood or silk), but are unsuitable for space-related applications due to production, manufacturing, or processing limitations. Large-scale ecosystem-based production, such as raising and harvesting trees for wood, is impractical in a self-contained habitat such as a space station or potential Mars colony. Manufacturing requirements, such as the specialized equipment needed to harvest and process cotton, add too much upmass for current launch technology. Cells in nature are already highly specialized for making complex biological materials on a micro scale. We envision combining these strengths with the recently emergent technologies of synthetic biology and 3D printing to create 3D-structured arrays of cells that are bioengineered to secrete different materials in a specified three-dimensional pattern.

  11. Certification of biological reference materials by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Lanjewar, Mamata R.; Lanjewar, R.B.

    2014-01-01

    A multielemental instrumental neutron activation analysis (INAA) method by short and long irradiation has been employed for the determination of 21 minor and trace elements in two standard Reference Materials P-RBF and P-WBF from Institute of Radioecology and Applied Nuclear Techniques ,Czechoslovakia. Also some biological standards such as Bowen's kale, cabbage leaves (Poland) including wheat and rice flour samples of local origin were analysed. It is suggested that INAA is an ideal method for the certification of Reference Materials of Biological Matrices. (author)

  12. Applications of Free Electron Lasers in Biology and Medicine

    International Nuclear Information System (INIS)

    Pelka, J.B.; Tybor, K.R.; Nietubyc, R.; Wrochna, G.

    2010-01-01

    The advent of free electron lasers opens up new opportunities to probe the dynamics of ultrafast processes and the structure of matter with unprecedented spatial and temporal resolution. New methods inaccessible with other known types of radiation sources can be developed, resulting in a breakthrough in deep understanding the fundamentals of life as well as in numerous medical and biological applications. In the present work the properties of free electron laser radiation that make the sources excellent for probing biological matter at an arbitrary wavelength, in a wide range of intensities and pulse durations are briefly discussed. A number of biophysical and biomedical applications of the new sources, currently considered among the most promising in the field, are presented. (author)

  13. Sustainable Materials Management (SMM) Electronics Challenge Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — On September 22, 2012, EPA launched the SMM Electronics Challenge. The Challenge encourages electronics manufacturers, brand owners and retailers to strive to send...

  14. NBS SRM 1569 Brewer's Yeast: Is it an adequate standard reference material for testing a chromium determination in biological materials tion in biological materials

    International Nuclear Information System (INIS)

    Goeij, J.J.M. de; Volkers, K.J.; Tjioe, P.S.; Kroon, J.J.

    1978-01-01

    Some analytical experiences with NBS SRM 1569 Brewer's Yeast are presented. Against this background the adequacy of this standard reference material for the determination of chromium in biological materials is discussed. Authors have three main objections. Due to its high content of insoluble chromium-containing particles, SRM 1569 is not typical for biological materials, possibly not even for Brewer's Yeast. The chromium level of SRM 1569 is not typical for the chromium levels normally encountered in pure biological materials. The major fraction (69 +- 3 percent) of the chromium is present in a form which is insoluble under the conditions used in Author's analysis. (T.I.)

  15. Electron Bifurcation: Thermodynamics and Kinetics of Two-Electron Brokering in Biological Redox Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Peng; Yuly, Jonathon L.; Lubner, Carolyn E. [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Mulder, David W. [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; King, Paul W. [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Peters, John W. [Institute; Beratan, David N. [Department

    2017-08-23

    How can proteins drive two electrons from a redox active donor onto two acceptors at very different potentials and distances? And how can this transaction be conducted without dissipating very much energy or violating the laws of thermodynamics? Nature appears to have addressed these challenges by coupling thermodynamically uphill and downhill electron transfer reactions, using two-electron donor cofactors that have very different potentials for the removal of the first and second electron. Although electron bifurcation is carried out with near perfection from the standpoint of energy conservation and electron delivery yields, it is a biological energy transduction paradigm that has only come into focus recently. This Account provides an exegesis of the biophysical principles that underpin electron bifurcation.

  16. Transmission electron microscopy in molecular structural biology: A historical survey.

    Science.gov (United States)

    Harris, J Robin

    2015-09-01

    In this personal, historic account of macromolecular transmission electron microscopy (TEM), published data from the 1940s through to recent times is surveyed, within the context of the remarkable progress that has been achieved during this time period. The evolution of present day molecular structural biology is described in relation to the associated biological disciplines. The contribution of numerous electron microscope pioneers to the development of the subject is discussed. The principal techniques for TEM specimen preparation, thin sectioning, metal shadowing, negative staining and plunge-freezing (vitrification) of thin aqueous samples are described, with a selection of published images to emphasise the virtues of each method. The development of digital image analysis and 3D reconstruction is described in detail as applied to electron crystallography and reconstructions from helical structures, 2D membrane crystals as well as single particle 3D reconstruction of icosahedral viruses and macromolecules. The on-going development of new software, algorithms and approaches is highlighted before specific examples of the historical progress of the structural biology of proteins and viruses are presented. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Transmission electron microscope studies of extraterrestrial materials

    Science.gov (United States)

    Keller, Lindsay P.

    1995-01-01

    Transmission Electron Microscopy, X-Ray spectrometry and electron-energy-loss spectroscopy are used to analyse carbon in interplanetary dust particles. Optical micrographs are shown depicting cross sections of the dust particles embedded in sulphur. Selected-area electron diffraction patterns are shown. Transmission Electron Microscope specimens of lunar soil were prepared using two methods: ion-milling and ultramicrotomy. A combination of high resolution TEM imaging and electron diffraction is used to characterize the opaque assemblages. The opaque assemblages analyzed in this study are dominated by ilmenite with lesser rutile and spinel exsolutions, and traces of Fe metal.

  18. Observation of defects evolution in electronic materials

    Science.gov (United States)

    Jang, Jung Hun

    Advanced characterization techniques have been used to obtain a better understanding of the microstructure of electronic materials. The structural evolution, especially defects, has been investigated during the film growth and post-growth processes. Obtaining the relation between the defect evolution and growth/post-growth parameters is very important to obtain highly crystalline films. In this work, the growth and post-growth related defects in GaN, ZnO, strained-Si/SiGe films have been studied using several advanced characterization techniques. First of all, the growth of related defects in GaN and p-type ZnO films have been studied. The effect of growth parameters, such as growth temperature, gas flow rate, dopants used during the deposition, on the crystalline quality of the GaN and ZnO layers was investigated by high resolution X-ray diffraction (HRXRD) and transmission electron microscopy (TEM). In GaN films, it was found that the edge and mixed type threading dislocations were the dominant defects so that the only relevant figure of merit (FOM) for the crystalline quality should be the FWHM value of o-RC of the surface perpendicular plane which could be determined by a grazing incidence x-ray diffraction (GIXD) technique as shown in this work. The understanding of the relationship between the defect evolution and growth parameters allowed for the growth of high crystalline GaN films. For ZnO films, it was found that the degree of texture and crystalline quality of P-doped ZnO films decreased with increasing the phosphorus atomic percent. In addition, the result from the x-ray diffraction line profile analysis showed that the 0.5 at % P-doped ZnO film showed much higher microstrain than the 1.0 at % P-doped ZnO film, which indicated that the phosphorus atoms were segregated with increasing P atomic percentage. Finally, post-growth related defects in strained-Si/SiGe films were investigated. Postgrowth processes used in this work included high temperature N2

  19. Biological evaluation of dental materials, in vitro and in vivo

    International Nuclear Information System (INIS)

    Kawahara, H.

    1982-01-01

    In this paper, the correlation between the user of tissue culture for in vitro tests and the tissue irritability and pupal response observed in in vitro tests, will be discussed. It would produce confusion if dental materials were standardised with the unreliable parameter of the living system in dynamic balance. Biological tests, both in vitro and in vivo, should be used for pre-standards testing, without any political control to establish physicochemical standards. As a first step, corrosion tests and the dissolution dosje of toxic components from the material in the tissue culture medium and/or artificial salvia should be standardised under conditions simulating the oral environment. The CNC method and photo-pattern analysis are used for the interpretation of cytotoxicity. The need for biological testing, both in vitro and in vivo, definitely exists in order to obtain physicochemical standards, with a biological simulation depending upon the feedback obtained from the results of in vitro and in vivo tests

  20. A national facility for biological cryo-electron microscopy

    International Nuclear Information System (INIS)

    Saibil, Helen R.; Grünewald, Kay; Stuart, David I.

    2015-01-01

    This review provides a brief update on the use of cryo-electron microscopy for integrated structural biology, along with an overview of the plans for the UK national facility for electron microscopy being built at the Diamond synchrotron. Three-dimensional electron microscopy is an enormously powerful tool for structural biologists. It is now able to provide an understanding of the molecular machinery of cells, disease processes and the actions of pathogenic organisms from atomic detail through to the cellular context. However, cutting-edge research in this field requires very substantial resources for equipment, infrastructure and expertise. Here, a brief overview is provided of the plans for a UK national three-dimensional electron-microscopy facility for integrated structural biology to enable internationally leading research on the machinery of life. State-of-the-art equipment operated with expert support will be provided, optimized for both atomic-level single-particle analysis of purified macromolecules and complexes and for tomography of cell sections. The access to and organization of the facility will be modelled on the highly successful macromolecular crystallography (MX) synchrotron beamlines, and will be embedded at the Diamond Light Source, facilitating the development of user-friendly workflows providing near-real-time experimental feedback

  1. The preparation of four biological reference materials for QUASIMEME

    NARCIS (Netherlands)

    Leeuwen, van S.P.J.; Pieters, H.; Boer, de J.

    2004-01-01

    Four biological materials have been prepared for use in QUASIMEME interlaboratory studies including a shrimp sample for metal analysis (QM01-1) and two mussel (QO01-3 and QO02-2) and one mackerel sample (QO02-1) for organic contaminant analysis.

  2. The determination of copper in biological materials by flame spectrophotometry

    Science.gov (United States)

    Newman, G. E.; Ryan, M.

    1962-01-01

    A method for the determination of the copper content of biological materials by flame spectrophotometry is described. The effects of interference by ions such as sodium and phosphate were eliminated by isolating copper as the dithizonate in CCl4. Results obtained for the urinary excretion of copper by a patient with Wilson's disease before and after treatment with penicillamine are reported. PMID:14479334

  3. Application of radiochemical separation procedures to environmental and biological materials

    Energy Technology Data Exchange (ETDEWEB)

    Eakins, J D [UKAEA Atomic Energy Research Establishment, Harwell. Environmental and Medical Sciences Div.

    1984-06-15

    The measurement of low levels of radionuclides in environmental and biological materials often depends on separation of the nuclide of interest from a bulky matrix containing interfering radioelements. In such case, however sophisticated and elegant the counting technique, the quality of the final data will

  4. Social justice and research using human biological material: A ...

    African Journals Online (AJOL)

    Social justice and research using human biological material: A response to Mahomed, Nöthling-Slabbert and Pepper. ... South African Medical Journal ... In a recent article, Mahomed, Nöthling-Slabbert and Pepper proposed that research participants should be entitled to share in the profits emanating from such research ...

  5. Theory of light transfer in food and biological materials

    Science.gov (United States)

    In this chapter, we first define the basic radiometric quantities that are needed for describing light propagation in food and biological materials. Radiative transfer theory is then derived, according to the principle of the conservation of energy. Because the radiative transfer theory equation is ...

  6. Biological applications of phase-contrast electron microscopy.

    Science.gov (United States)

    Nagayama, Kuniaki

    2014-01-01

    Here, I review the principles and applications of phase-contrast electron microscopy using phase plates. First, I develop the principle of phase contrast based on a minimal model of microscopy, introducing a double Fourier-transform process to mathematically formulate the image formation. Next, I explain four phase-contrast (PC) schemes, defocus PC, Zernike PC, Hilbert differential contrast, and schlieren optics, as image-filtering processes in the context of the minimal model, with particular emphases on the Zernike PC and corresponding Zernike phase plates. Finally, I review applications of Zernike PC cryo-electron microscopy to biological systems such as protein molecules, virus particles, and cells, including single-particle analysis to delineate three-dimensional (3D) structures of protein and virus particles and cryo-electron tomography to reconstruct 3D images of complex protein systems and cells.

  7. Advanced materials for thermal management of electronic packaging

    CERN Document Server

    Tong, Xingcun Colin

    2011-01-01

    The need for advanced thermal management materials in electronic packaging has been widely recognized as thermal challenges become barriers to the electronic industry's ability to provide continued improvements in device and system performance. With increased performance requirements for smaller, more capable, and more efficient electronic power devices, systems ranging from active electronically scanned radar arrays to web servers all require components that can dissipate heat efficiently. This requires that the materials have high capability of dissipating heat and maintaining compatibility

  8. Modelling low energy electron and positron tracks in biologically relevant media

    International Nuclear Information System (INIS)

    Blanco, F.; Munoz, A.; Almeida, D.; Ferreira da Silva, F.; Limao-Vieira, P.; Fuss, M.C.; Sanz, A.G.; Garcia, G.

    2013-01-01

    This colloquium describes an approach to incorporate into radiation damage models the effect of low and intermediate energy (0-100 eV) electrons and positrons, slowing down in biologically relevant materials (water and representative biomolecules). The core of the modelling procedure is a C++ computing programme named 'Low Energy Particle Track Simulation (LEPTS)', which is compatible with available general purpose Monte Carlo packages. Input parameters are carefully selected from theoretical and experimental cross section data and energy loss distribution functions. Data sources used for this purpose are reviewed showing examples of electron and positron cross section and energy loss data for interactions with different media of increasing complexity: atoms, molecules, clusters and condense matter. Finally, we show how such a model can be used to develop an effective dosimetric tool at the molecular level (i.e. nanodosimetry). Recent experimental developments to study the fragmentation induced in biologically material by charge transfer from neutrals and negative ions are also included. (authors)

  9. Lipid Bilayer Formation on Organic Electronic Materials

    KAUST Repository

    Zhang, Yi; Wustoni, Shofarul; Savva, Achilleas; Giovannitti, Alexander; McCulloch, Iain; Inal, Sahika

    2018-01-01

    The lipid bilayer is the elemental structure of cell membrane, forming a stable barrier between the interior and exterior of the cell while hosting membrane proteins that enable selective transport of biologically important compounds and cellular

  10. Electronic and optoelectronic materials and devices inspired by nature

    Science.gov (United States)

    Meredith, P.; Bettinger, C. J.; Irimia-Vladu, M.; Mostert, A. B.; Schwenn, P. E.

    2013-03-01

    Inorganic semiconductors permeate virtually every sphere of modern human existence. Micro-fabricated memory elements, processors, sensors, circuit elements, lasers, displays, detectors, etc are ubiquitous. However, the dawn of the 21st century has brought with it immense new challenges, and indeed opportunities—some of which require a paradigm shift in the way we think about resource use and disposal, which in turn directly impacts our ongoing relationship with inorganic semiconductors such as silicon and gallium arsenide. Furthermore, advances in fields such as nano-medicine and bioelectronics, and the impending revolution of the ‘ubiquitous sensor network’, all require new functional materials which are bio-compatible, cheap, have minimal embedded manufacturing energy plus extremely low power consumption, and are mechanically robust and flexible for integration with tissues, building structures, fabrics and all manner of hosts. In this short review article we summarize current progress in creating materials with such properties. We focus primarily on organic and bio-organic electronic and optoelectronic systems derived from or inspired by nature, and outline the complex charge transport and photo-physics which control their behaviour. We also introduce the concept of electrical devices based upon ion or proton flow (‘ionics and protonics’) and focus particularly on their role as a signal interface with biological systems. Finally, we highlight recent advances in creating working devices, some of which have bio-inspired architectures, and summarize the current issues, challenges and potential solutions. This is a rich new playground for the modern materials physicist.

  11. The Diverse Ecology of Electronic Materials

    NARCIS (Netherlands)

    Mody, Cyrus C.M.; Teissier, Pierre; Mody, Cyrus C. M.; Tiggelen, Brigitte van

    2017-01-01

    Silicon has been the dominant material in microelectronics for a half century. Other materials, however, have subsidiary roles in microelectronics manufacturing. A few materials have even been promoted as replacements for silicon. Yet because of silicon’s dominance, none of these alternatives has

  12. Fuel from biologic wase materials; Kraftstoff aus biologischen Reststoffen

    Energy Technology Data Exchange (ETDEWEB)

    Braesel, Martina

    2013-06-01

    In Germany, annually about 770,000 tons of biological waste reach rubbish bins or composting plants. In order to recondition this biological waste, the Federal Ministry of Education and Research (Berlin, Federal Republic of Germany) has launched a research project with a funding of 4.3 million Euro limited to a period of time of five years. In cooperation with the Fraunhofer Institute for Interfacial Engineering and Biotechnology (Stuttgart, Federal Republic of Germany) easily fermentable, wet biomass with a low content of lignocellulosic material has to be completely transformed to biogas with maximum energy. Only some of the ash remains.

  13. Transport of biologically active material in laser cutting.

    Science.gov (United States)

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

    1988-01-01

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

  14. Electron Bifurcation: Thermodynamics and Kinetics of Two-Electron Brokering in Biological Redox Chemistry.

    Science.gov (United States)

    Zhang, Peng; Yuly, Jonathon L; Lubner, Carolyn E; Mulder, David W; King, Paul W; Peters, John W; Beratan, David N

    2017-09-19

    How can proteins drive two electrons from a redox active donor onto two acceptors at very different potentials and distances? And how can this transaction be conducted without dissipating very much energy or violating the laws of thermodynamics? Nature appears to have addressed these challenges by coupling thermodynamically uphill and downhill electron transfer reactions, using two-electron donor cofactors that have very different potentials for the removal of the first and second electron. Although electron bifurcation is carried out with near perfection from the standpoint of energy conservation and electron delivery yields, it is a biological energy transduction paradigm that has only come into focus recently. This Account provides an exegesis of the biophysical principles that underpin electron bifurcation. Remarkably, bifurcating electron transfer (ET) proteins typically send one electron uphill and one electron downhill by similar energies, such that the overall reaction is spontaneous, but not profligate. Electron bifurcation in the NADH-dependent reduced ferredoxin: NADP + oxidoreductase I (Nfn) is explored in detail here. Recent experimental progress in understanding the structure and function of Nfn allows us to dissect its workings in the framework of modern ET theory. The first electron that leaves the two-electron donor flavin (L-FAD) executes a positive free energy "uphill" reaction, and the departure of this electron switches on a second thermodynamically spontaneous ET reaction from the flavin along a second pathway that moves electrons in the opposite direction and at a very different potential. The singly reduced ET products formed from the bifurcating flavin are more than two nanometers distant from each other. In Nfn, the second electron to leave the flavin is much more reducing than the first: the potentials are said to be "crossed." The eventually reduced cofactors, NADH and ferredoxin in the case of Nfn, perform crucial downstream redox

  15. Noncovalent Interactions in Organic Electronic Materials

    KAUST Repository

    Ravva, Mahesh Kumar; Risko, Chad; Bredas, Jean-Luc

    2017-01-01

    In this chapter, we provide an overview of how noncovalent interactions, determined by the chemical structure of π-conjugated molecules and polymers, govern essential aspects of the electronic, optical, and mechanical characteristics of organic

  16. Conjugated material self-assembly : towards supramolecular electronics

    NARCIS (Netherlands)

    Leclère, P.E.L.G.; Surin, M.; Cavallini, M.; Jonkheijm, P.; Henze, O.; Schenning, A.P.H.J.; Biscarini, F.; Grimsdale, A.C.; Feast, W.J.; Meijer, E.W.; Müllen, K.; Brédas, J.L.; Lazzaroni, R.

    2004-01-01

    Properties of organic electronic materials in solid-state are determined as individual molecules and molecular assembly. It is essential to optimize conjugated materials to control performance of molecular assembly that constitute electronic devices such as light-emitting diodes and solar cells, and

  17. Amorphous electron-accepting materials for organic optoelectronics

    NARCIS (Netherlands)

    Ganesan, P.

    2007-01-01

    The importance of organic materials for use in electronic devices such as OLEDs, OFETs and photovoltaic cells has increased significantly over the past decade. Organic materials have been attractive candidates for such electronic devices because of their compatibility with high-throughput,

  18. Material machining with pseudo-spark electron beams

    International Nuclear Information System (INIS)

    Benker, W.; Christiansen, J.; Frank, K.; Gundel, H.; Redel, T.; Stetter, M.

    1989-01-01

    The authors give a brief description of the production of pseudo-spark (low pressure gas discharge) electron beams. They illustrate the use of these electron beams for machining not only conducting, semiconducting and insulating materials, but also thin layers of such materials as high temperature superconducting ceramics

  19. INAA Application for Trace Element Determination in Biological Reference Material

    Science.gov (United States)

    Atmodjo, D. P. D.; Kurniawati, S.; Lestiani, D. D.; Adventini, N.

    2017-06-01

    Trace element determination in biological samples is often used in the study of health and toxicology. Determination change to its essentiality and toxicity of trace element require an accurate determination method, which implies that a good Quality Control (QC) procedure should be performed. In this study, QC for trace element determination in biological samples was applied by analyzing the Standard Reference Material (SRM) Bovine muscle 8414 NIST using Instrumental Neutron Activation Analysis (INAA). Three selected trace element such as Fe, Zn, and Se were determined. Accuracy of the elements showed as %recovery and precision as %coefficient of variance (%CV). The result showed that %recovery of Fe, Zn, and Se were in the range between 99.4-107%, 92.7-103%, and 91.9-112%, respectively, whereas %CV were 2.92, 3.70, and 5.37%, respectively. These results showed that INAA method is precise and accurate for trace element determination in biological matrices.

  20. FDTD simulation of exposure of biological material to electromagnetic nanopulses

    Energy Technology Data Exchange (ETDEWEB)

    Simicevic, Neven [Center for Applied Physics Studies, Louisiana Tech University, Ruston, LA 71272 (United States); Haynie, Donald T [Center for Applied Physics Studies and Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272 (United States)

    2005-01-21

    Ultra-wideband (UWB) electromagnetic pulses of nanosecond duration, or nanopulses, are of considerable interest to the communications industry and are being explored for various applications in biotechnology and medicine. The propagation of a nanopulse through biological matter has been computed using the finite difference-time domain (FDTD) method. The approach required the reparametrization of existing Cole-Cole model-based descriptions of dielectric properties of biological matter in terms of the Debye model without loss of accuracy. Several tissue types have been considered. Results show that the electromagnetic field inside biological tissue depends on incident pulse rise time and width. Rise time dominates pulse behaviour inside tissue as conductivity increases. It has also been found that the amount of energy deposited by 20 kV m{sup -1} nanopulses is insufficient to change the temperature of the exposed material for pulse repetition rates of 1 MHz or less, consistent with recent experimental results.

  1. [The meaning of accidents with biological material to nursing professionals].

    Science.gov (United States)

    Magagnini, Maristela Aparecida Magri; Rocha, Suelen Alves; Ayres, Jairo Aparecido

    2011-06-01

    The aim of this study is to understand what meaning work accidents with exposure to biological material has to nurses. This is an exploratory study with a qualitative approach, and it used Bardin's content analysis. 87 accidents with biological material occurred in the period between 2001 and 2006; among them, eight were seropositive for Hepatitis B and C and HIV/AIDS. An interview with guiding questions was used to collect data. When inquiring these professionals about the meaning of these accidents, four categories emerged: risk situation, danger perception, fatality, and feelings. Although it is not a strategy of clarification, it is a fact that work organization and educative actions have considerable impact in reducing this type of accident, also reducing damage to the life of nurses involved in these accidents.

  2. Charged particle activation analysis of phosphorus in biological materials

    International Nuclear Information System (INIS)

    Masumoto, K.; Yagi, M.

    1983-01-01

    Charged particle activation analysis of phosphorus in biological materials using the 31 P(α,n) sup(34m)Cl reaction has been studied. Since sup(34m)Cl is also produced by the 32 S(α,pn) and the 35 Cl(α,α'n) reactions, the thick-target yield curves on phosphorus, sulfur and chlorine were determined in order to choose the optimum irradiation conditions. As a result, it was found that the activation analysis for phosphorus without interferences from sulfur and chlorine is possible by bombarding with less than 17 MeV alphas. The applicability of this method to biological samples was then examined by irradiating several standard reference materials. It was confirmed that phosphorus can readily be determined at the detection limit of 1μg free from interferences due to the matrix elements. (author)

  3. Membrane materials for storing biological samples intended for comparative nanotoxicological testing

    Science.gov (United States)

    Metelkin, A.; Kuznetsov, D.; Kolesnikov, E.; Chuprunov, K.; Kondakov, S.; Osipov, A.; Samsonova, J.

    2015-11-01

    The study is aimed at identifying the samples of most promising membrane materials for storing dry specimens of biological fluids (Dried Blood Spots, DBS technology). Existing sampling systems using cellulose fiber filter paper have a number of drawbacks such as uneven distribution of the sample spot, dependence of the spot spreading area on the individual biosample properties, incomplete washing-off of the sample due to partially inconvertible sorption of blood components on cellulose fibers, etc. Samples of membrane materials based on cellulose, polymers and glass fiber with applied biosamples were studied using methods of scanning electron microscopy, FT-IR spectroscopy and surface-wetting measurement. It was discovered that cellulose-based membrane materials sorb components of biological fluids inside their structure, while membranes based on glass fiber display almost no interaction with the samples and biological fluid components dry to films in the membrane pores between the structural fibers. This characteristic, together with the fact that membrane materials based on glass fiber possess sufficient strength, high wetting properties and good storage capacity, attests them as promising material for dry samples of biological fluids storage systems.

  4. Membrane materials for storing biological samples intended for comparative nanotoxicological testing

    International Nuclear Information System (INIS)

    Metelkin, A; Kuznetsov, D; Kolesnikov, E; Chuprunov, K; Kondakov, S; Osipov, A; Samsonova, J

    2015-01-01

    The study is aimed at identifying the samples of most promising membrane materials for storing dry specimens of biological fluids (Dried Blood Spots, DBS technology). Existing sampling systems using cellulose fiber filter paper have a number of drawbacks such as uneven distribution of the sample spot, dependence of the spot spreading area on the individual biosample properties, incomplete washing-off of the sample due to partially inconvertible sorption of blood components on cellulose fibers, etc. Samples of membrane materials based on cellulose, polymers and glass fiber with applied biosamples were studied using methods of scanning electron microscopy, FT-IR spectroscopy and surface-wetting measurement. It was discovered that cellulose-based membrane materials sorb components of biological fluids inside their structure, while membranes based on glass fiber display almost no interaction with the samples and biological fluid components dry to films in the membrane pores between the structural fibers. This characteristic, together with the fact that membrane materials based on glass fiber possess sufficient strength, high wetting properties and good storage capacity, attests them as promising material for dry samples of biological fluids storage systems. (paper)

  5. Prompt gamma cold neutron activation analysis applied to biological materials

    International Nuclear Information System (INIS)

    Rossbach, M.; Hiep, N.T.

    1992-01-01

    Cold neutrons at the external neutron guide laboratory (ELLA) of the KFA Juelich are used to demonstrate their profitable application for multielement characterization of biological materials. The set-up and experimental conditions of the Prompt Gamma Cold Neutron Activation Analysis (PGCNAA) device is described in detail. Results for C, H, N, S, K, B, and Cd using synthetic standards and the 'ratio' technique for calculation are reported for several reference materials and prove the method to be reliable and complementary with respect to the elements being determined by INAA. (orig.)

  6. Routine Determination of Arsenic in Biological Materials. RCN Report

    International Nuclear Information System (INIS)

    Kroon, J.J.; Das, H.A.

    1970-08-01

    This text describes a routine procedure for the determination of arsenic in biological materials by neutron activation analysis. Unlike most methods published in literature the present analysis is not based on chemical separation by destination. After a first purification by anion-exchange the 76 As-activity (T1/2 = 26,4 h) is isolated by precipitation as the metal. The method was tested by analysis of the standard kale powder. This material was prepared and issued by Bowen in 1966, to provide a reliable standard for the intercomparison of various methods. (author)

  7. Electron microscopy of some exotic materials

    International Nuclear Information System (INIS)

    Mitchell, T.E.

    1998-01-01

    Just about every material has been looked at under the microscope, either out of pure inquisitiveness or the need to relate the microstructure to its properties. Some of these materials are mundane, like steels or glass or polyethylene; others are so-called advanced, such as intermetallics, silicon nitride or zirconia; yet others might be called exotic whether they be martian rocks, high temperature superconductors, fullerenes, diamonds, or the latest thin film device. Many exotic materials are important in Los Alamos, not only weapons materials such as actinides, tritium and explosives, but also civilian materials for energy applications. Here the author will report briefly on plutonium and uranium, on rhenium disilicide, and on Cu-Nb nanolayered composites

  8. Biologically inspired autonomous structural materials with controlled toughening and healing

    Science.gov (United States)

    Garcia, Michael E.; Sodano, Henry A.

    2010-04-01

    The field of structural health monitoring (SHM) has made significant contributions in the field of prognosis and damage detection in the past decade. The advantageous use of this technology has not been integrated into operational structures to prevent damage from propagating or to heal injured regions under real time loading conditions. Rather, current systems relay this information to a central processor or human operator, who then determines a course of action such as altering the mission or scheduling repair maintenance. Biological systems exhibit advanced sensory and healing traits that can be applied to the design of material systems. For instance, bone is the major structural component in vertebrates; however, unlike modern structural materials, bone has many properties that make it effective for arresting the propagation of cracks and subsequent healing of the fractured area. The foremost goal for the development of future adaptive structures is to mimic biological systems, similar to bone, such that the material system can detect damage and deploy defensive traits to impede damage from propagating, thus preventing catastrophic failure while in operation. After sensing and stalling the propagation of damage, the structure must then be repaired autonomously using self healing mechanisms motivated by biological systems. Here a novel autonomous system is developed using shape memory polymers (SMPs), that employs an optical fiber network as both a damage detection sensor and a network to deliver stimulus to the damage site initiating adaptation and healing. In the presence of damage the fiber optic fractures allowing a high power laser diode to deposit a controlled level of thermal energy at the fractured sight locally reducing the modulus and blunting the crack tip, which significantly slows the crack growth rate. By applying a pre-induced strain field and utilizing the shape memory recovery effect, thermal energy can be deployed to close the crack and return

  9. Electron emission from materials at low excitation energies

    International Nuclear Information System (INIS)

    Urma, N.; Kijek, M.; Millar, J.J.

    1996-01-01

    Full text: An experimental system has been designed and developed with the purpose of measuring the total electron emission yield from materials at low energy excitation. In the first instance the reliability of the system was checked by measuring the total electron emission yield for a well defined surface (aluminium 99.45%). The obtained data was in the expected range given by the literature, and consequently the system will be used further for measuring the total electron yield for a range of materials with interest in the instrumentation industry. We intend to measure the total electron emission yield under electron bombardment as a function of incident electron energy up to 1200 eV, angle of incidence, state of the surface and environment to which the surface has been exposed. Dependence of emission on total electron irradiated dose is also of interest. For many practical application of the 'Secondary Electron Emission', the total electron yield is desired to be as large as possible. The above phenomenon has practical applicability in electron multiplier tube and Scanning electron microscopy - when by means of the variation of the yield of the emitted electrons one may produce visible images of small sample areas. The electron multiplier tube, is a device which utilises the above effect to detect and amplify both single particles and low currents streams of charged particles. The majority of electron tubes use electrons with low energy, hundreds of eV. Not a lot has been published in the literature about this regime and also about the emission when the impinging electrons have small energy, up to 1 KeV. The information obtained from the experimental measurements concerning the total electron emission yield is used to asses the investigated materials as a potential electron emitting surfaces or dynodes in an electron multiplier tube

  10. Diffusion theory in biology: a relic of mechanistic materialism.

    Science.gov (United States)

    Agutter, P S; Malone, P C; Wheatley, D N

    2000-01-01

    Diffusion theory explains in physical terms how materials move through a medium, e.g. water or a biological fluid. There are strong and widely acknowledged grounds for doubting the applicability of this theory in biology, although it continues to be accepted almost uncritically and taught as a basis of both biology and medicine. Our principal aim is to explore how this situation arose and has been allowed to continue seemingly unchallenged for more than 150 years. The main shortcomings of diffusion theory will be briefly reviewed to show that the entrenchment of this theory in the corpus of biological knowledge needs to be explained, especially as there are equally valid historical grounds for presuming that bulk fluid movement powered by the energy of cell metabolism plays a prominent note in the transport of molecules in the living body. First, the theory's evolution, notably from its origins in connection with the mechanistic materialist philosophy of mid nineteenth century physiology, is discussed. Following this, the entrenchment of the theory in twentieth century biology is analyzed in relation to three situations: the mechanism of oxygen transport between air and mammalian tissues; the structure and function of cell membranes; and the nature of the intermediary metalbolism, with its implicit presumptions about the intracellular organization and the movement of molecules within it. In our final section, we consider several historically based alternatives to diffusion theory, all of which have their precursors in nineteenth and twentieth century philosophy of science.

  11. 76 FR 65212 - Henkel Corporation, Currently Known as Henkel Electronic Materials, LLC, Electronic Adhesives...

    Science.gov (United States)

    2011-10-20

    ..., Currently Known as Henkel Electronic Materials, LLC, Electronic Adhesives Division, Including On-Site Leased..., Electronic Adhesives Division, including on-site leased workers from Aerotek Professional Services, Billerica..., Electronic Adhesives Division had their wages reported under a separate unemployment insurance (UI) tax...

  12. Scanning electron microscopy of semiconductor materials

    International Nuclear Information System (INIS)

    Bresse, J.F.; Dupuy, M.

    1978-01-01

    The use of scanning electron microscopy in semiconductors opens up a large field of use. The operating modes lending themselves to the study of semiconductors are the induced current, cathodoluminescence and the use of the potential contrast which can also be applied very effectively to the study of the devices (planar in particular). However, a thorough knowledge of the mechanisms of the penetration of electrons, generation and recombination of generated carriers in a semiconductor is necessary in order to attain a better understanding of the operating modes peculiar to semiconductors [fr

  13. Electron probe analysis of biological fluids: Possibilities and limitations

    International Nuclear Information System (INIS)

    Roinel, N.

    1984-01-01

    Physical methods of investigation have become essential to investigations at the cellular or subcellular level. Nuclear magnetic resonance is the most recent and striking example, since it is not only a tool for fundamental physicists and organic chemists, but also an extraordinary powerful imaging tool for physicians. The absorption properties of X rays were used immediately after their discovery to image the bones of skeletons. Later, X rays were also found to be extremely efficient in the measurement of the elemental content of microvolumes irradiated by electron probes. The electron probe analyzer (EPA) was immediately adopted by numerous laboratories of metallurgy, geology, and mineral sciences. In the last fifteen years, since the use of this instrument was suggested for liquid analysis, and a preparative technique was developed, the EPA has been used by an increasing number of biological laboratories for measuring the concentrations of the elements contained in subnanoliter volumes of biological fluids. The so-called microdroplet technique has become a routine laboratory method, the only one able to measure the concentrations of an unlimited number of elements in a single 0.1-nl sample. This explains its use in fields as various as renal, reproductive, digestive, and plant physiology, zoology, etc. Several review papers discuss these applications. The possibilities and limitations of the technique are discussed below

  14. Inorganic-organic hybrid polymer for preparation of affiliating material using electron beam irradiation

    International Nuclear Information System (INIS)

    Chung, Jaeseung; Kim, Seongeun; Kim, Byounggak; Lee, Jongchan; Park, Jihyun; Lee, Byeongcheol

    2011-01-01

    Recently, silver nano materials have gained a lot of attentions in a variety of applications due to the unique biological, optical, and electrical properties. Especially, the antifouling property of these material is considered to be an important character for biomedical field, marine coatings industry, biosensor, and drug delivery. In this study, we design and synthesize the inorganic-organic hybrid polymer for preparation of affiliating materials. Silver nano materials having antifouling property with different shapes are prepared by control the electron beam irradiation conditions. Inorganic-organic hybrid polymer was synthesized and characterized. → Morphology and size controlled nano materials are prepared using electron beam irradiation. → Silver nano materials having various shapes can be used for antifouling material

  15. Radiation damage relative to transmission electron microscopy of biological specimens at low temperature: a review

    International Nuclear Information System (INIS)

    Glaeser, R.M.; Taylor, K.A.

    1978-01-01

    When biological specimens are irradiated by the electron beam in the electron microscope, the specimen structure is damaged as a result of molecular excitation, ionization, and subsequent chemical reactions. The radiation damage that occurs in the normal process of electron microscopy is known to present severe limitations for imaging high resolution detail in biological specimens. The question of radiation damage at low temperatures has therefore been investigated with the view in mind of reducing somewhat the rate at which damage occurs. The radiation damage protection found for small molecule (anhydrous) organic compounds is generally rather limited or even non-existent. However, large molecule, hydrated materials show as much as a 10-fold reduction at low temperature in the rate at which radiation damage occurs, relative to the damage rate at room temperature. In the case of hydrated specimens, therefore, low temperature electron microscopy offers an important advantage as part of the overall effort required in obtaining high resolution images of complex biological structures. (author)

  16. Certification of biological candidates reference materials by neutron activation analysis

    Science.gov (United States)

    Kabanov, Denis V.; Nesterova, Yulia V.; Merkulov, Viktor G.

    2018-03-01

    The paper gives the results of interlaboratory certification of new biological candidate reference materials by neutron activation analysis recommended by the Institute of Nuclear Chemistry and Technology (Warsaw, Poland). The correctness and accuracy of the applied method was statistically estimated for the determination of trace elements in candidate reference materials. The procedure of irradiation in the reactor thermal fuel assembly without formation of fast neutrons was carried out. It excluded formation of interfering isotopes leading to false results. The concentration of more than 20 elements (e.g., Ba, Br, Ca, Co, Ce, Cr, Cs, Eu, Fe, Hf, La, Lu, Rb, Sb, Sc, Ta, Th, Tb, Yb, U, Zn) in candidate references of tobacco leaves and bottom sediment compared to certified reference materials were determined. It was shown that the average error of the applied method did not exceed 10%.

  17. Soluble phthalocyanines: perspective materials for electronics

    Czech Academy of Sciences Publication Activity Database

    Nešpůrek, Stanislav; Chaidogiannos, G.; Glezos, N.; Wang, G.; Böhm, S.; Rakušan, J.; Karásková, M.

    2007-01-01

    Roč. 468, č. 2 (2007), 3/[355]-21/[373] ISSN 1542-1406 R&D Projects: GA AV ČR KAN401770651; GA MPO FT-TA/036; GA MŠk OC 138 Institutional research plan: CEZ:AV0Z40500505 Keywords : FET transistors * humidity sensors * organic semiconductors Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.554, year: 2007

  18. Three-Dimensional scanning transmission electron microscopy of biological specimens

    KAUST Repository

    De Jonge, Niels

    2010-01-18

    A three-dimensional (3D) reconstruction of the cytoskeleton and a clathrin-coated pit in mammalian cells has been achieved from a focal-series of images recorded in an aberration-corrected scanning transmission electron microscope (STEM). The specimen was a metallic replica of the biological structure comprising Pt nanoparticles 2-3 nm in diameter, with a high stability under electron beam radiation. The 3D dataset was processed by an automated deconvolution procedure. The lateral resolution was 1.1 nm, set by pixel size. Particles differing by only 10 nm in vertical position were identified as separate objects with greater than 20% dip in contrast between them. We refer to this value as the axial resolution of the deconvolution or reconstruction, the ability to recognize two objects, which were unresolved in the original dataset. The resolution of the reconstruction is comparable to that achieved by tilt-series transmission electron microscopy. However, the focal-series method does not require mechanical tilting and is therefore much faster. 3D STEM images were also recorded of the Golgi ribbon in conventional thin sections containing 3T3 cells with a comparable axial resolution in the deconvolved dataset. © 2010 Microscopy Society of America.

  19. OECD Policy Recommendations on Security for Biological Materials

    International Nuclear Information System (INIS)

    Radisch, J.

    2007-01-01

    Biomedical innovations derived from research on pathogenic micro-organisms promise astounding health and economic benefits. Some such biological resources employed in the RandD for diagnostic kits, vaccines and therapeutics, however, possess capacity for dual-use; they may be misused to develop biological weapons. Research facilities entrusted with possession of such dual-use materials have a responsibility to comply with biosecurity measures that are designed to prevent loss or theft and thereby reduce the probability of a bioterrorist attack. The OECD has provided a forum for its Member countries to engage in a dialogue of international co-operation with a view to produce policies that achieve a research environment fortified by biosecurity measures and capable of producing health innovations. In 2007, the OECD developed a risk assessment framework and risk management principles for Biological Resource Centres. Ongoing policy work at the OECD will look to design biosecurity guidelines appropriate to a broader range of facilities in possession of dual-use materials, such as university and industrial laboratories.(author)

  20. A model of engineering materials inspired by biological tissues

    Directory of Open Access Journals (Sweden)

    Holeček M.

    2009-12-01

    Full Text Available The perfect ability of living tissues to control and adapt their mechanical properties to varying external conditions may be an inspiration for designing engineering materials. An interesting example is the smooth muscle tissue since this "material" is able to change its global mechanical properties considerably by a subtle mechanism within individual muscle cells. Multi-scale continuum models may be useful in designing essentially simpler engineering materials having similar properties. As an illustration we present the model of an incompressible material whose microscopic structure is formed by flexible, soft but incompressible balls connected mutually by linear springs. This simple model, however, shows a nontrivial nonlinear behavior caused by the incompressibility of balls and is very sensitive on some microscopic parameters. It may elucidate the way by which "small" changes in biopolymer networks within individual muscular cells may control the stiffness of the biological tissue, which outlines a way of designing similar engineering materials. The 'balls and springs' material presents also prestress-induced stiffening and allows elucidating a contribution of extracellular fluids into the tissue’s viscous properties.

  1. First Principles Calculations of Electronic Excitations in 2D Materials

    DEFF Research Database (Denmark)

    Rasmussen, Filip Anselm

    electronic transport, optical and chemical properties. On the other hand it has shown to be a great starting point for a systematic pertubation theory approach to obtain the so-called quasiparticle spectrum. In the GW approximation one considers the considers the potential from a charged excitation...... as if it is being screened by the electrons in the material. This method has been very successful for calculating quasiparticle energies of bulk materials but results have been more varying for 2D materials. The reason is that the 2D confined electrons are less able to screen the added charge and some...

  2. Electron holography of Fe-based nanocrystalline magnetic materials (invited)

    International Nuclear Information System (INIS)

    Shindo, Daisuke; Park, Young-Gil; Gao, Youhui; Park, Hyun Soon

    2004-01-01

    Magnetic domain structures of nanocrystalline magnetic materials were extensively investigated by electron holography with a change in temperature or magnetic field applied. In both soft and hard magnetic materials, the distribution of lines of magnetic flux clarified in situ by electron holography was found to correspond well to their magnetic properties. An attempt to produce a strong magnetic field using a sharp needle made of a permanent magnet, whose movement is controlled by piezo drives has been presented. This article demonstrates that the attempt is promising to investigate the magnetization process of hard magnetic materials by electron holography

  3. Electronic and optoelectronic materials and devices inspired by nature

    International Nuclear Information System (INIS)

    Meredith, P; Schwenn, P E; Bettinger, C J; Irimia-Vladu, M; Mostert, A B

    2013-01-01

    Inorganic semiconductors permeate virtually every sphere of modern human existence. Micro-fabricated memory elements, processors, sensors, circuit elements, lasers, displays, detectors, etc are ubiquitous. However, the dawn of the 21st century has brought with it immense new challenges, and indeed opportunities—some of which require a paradigm shift in the way we think about resource use and disposal, which in turn directly impacts our ongoing relationship with inorganic semiconductors such as silicon and gallium arsenide. Furthermore, advances in fields such as nano-medicine and bioelectronics, and the impending revolution of the ‘ubiquitous sensor network’, all require new functional materials which are bio-compatible, cheap, have minimal embedded manufacturing energy plus extremely low power consumption, and are mechanically robust and flexible for integration with tissues, building structures, fabrics and all manner of hosts. In this short review article we summarize current progress in creating materials with such properties. We focus primarily on organic and bio-organic electronic and optoelectronic systems derived from or inspired by nature, and outline the complex charge transport and photo-physics which control their behaviour. We also introduce the concept of electrical devices based upon ion or proton flow (‘ionics and protonics’) and focus particularly on their role as a signal interface with biological systems. Finally, we highlight recent advances in creating working devices, some of which have bio-inspired architectures, and summarize the current issues, challenges and potential solutions. This is a rich new playground for the modern materials physicist. (review article)

  4. High Resolution Electron Microscopy in Materials Science

    International Nuclear Information System (INIS)

    Amelinckx, S.

    1986-01-01

    This paper illustrates different operating modes of the electron microscope and shows the image formation in an ideal microscope. Diffraction contrast is used in the study of crystal defects, such as dislocations and planar interfaces. Methods are surveyed which give at least a rudimentary image of the lattice and therefore make use of at least two interfering beams. Special attention is given to images which also carry structural information and therefore imply the use of many beams. The underlying theory is discussed as are the theories of Van Dyck, Spence and Cowley. These are illustrated by means of a number of recent case studies

  5. Holmium hafnate: An emerging electronic device material

    International Nuclear Information System (INIS)

    Pavunny, Shojan P.; Sharma, Yogesh; Kooriyattil, Sudheendran; Dugu, Sita; Katiyar, Rajesh K.; Katiyar, Ram S.; Scott, James F.

    2015-01-01

    We report structural, optical, charge transport, and temperature properties as well as the frequency dependence of the dielectric constant of Ho 2 Hf 2 O 7 (HHO) which make this material desirable as an alternative high-k dielectric for future silicon technology devices. A high dielectric constant of ∼20 and very low dielectric loss of ∼0.1% are temperature and voltage independent at 100 kHz near ambient conditions. The Pt/HHO/Pt capacitor exhibits exceptionally low Schottky emission-based leakage currents. In combination with the large observed bandgap E g of 5.6 eV, determined by diffuse reflectance spectroscopy, our results reveal fundamental physics and materials science of the HHO metal oxide and its potential application as a high-k dielectric for the next generation of complementary metal-oxide-semiconductor devices

  6. Holmium hafnate: An emerging electronic device material

    Science.gov (United States)

    Pavunny, Shojan P.; Sharma, Yogesh; Kooriyattil, Sudheendran; Dugu, Sita; Katiyar, Rajesh K.; Scott, James F.; Katiyar, Ram S.

    2015-03-01

    We report structural, optical, charge transport, and temperature properties as well as the frequency dependence of the dielectric constant of Ho2Hf2O7 (HHO) which make this material desirable as an alternative high-k dielectric for future silicon technology devices. A high dielectric constant of ˜20 and very low dielectric loss of ˜0.1% are temperature and voltage independent at 100 kHz near ambient conditions. The Pt/HHO/Pt capacitor exhibits exceptionally low Schottky emission-based leakage currents. In combination with the large observed bandgap Eg of 5.6 eV, determined by diffuse reflectance spectroscopy, our results reveal fundamental physics and materials science of the HHO metal oxide and its potential application as a high-k dielectric for the next generation of complementary metal-oxide-semiconductor devices.

  7. Holmium hafnate: An emerging electronic device material

    Energy Technology Data Exchange (ETDEWEB)

    Pavunny, Shojan P., E-mail: shojanpp@gmail.com, E-mail: rkatiyar@hpcf.upr.edu; Sharma, Yogesh; Kooriyattil, Sudheendran; Dugu, Sita; Katiyar, Rajesh K.; Katiyar, Ram S., E-mail: shojanpp@gmail.com, E-mail: rkatiyar@hpcf.upr.edu [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, P.O. Box 70377, San Juan, Puerto Rico 00936-8377 (United States); Scott, James F. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, P.O. Box 70377, San Juan, Puerto Rico 00936-8377 (United States); Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 OHE (United Kingdom)

    2015-03-16

    We report structural, optical, charge transport, and temperature properties as well as the frequency dependence of the dielectric constant of Ho{sub 2}Hf{sub 2}O{sub 7} (HHO) which make this material desirable as an alternative high-k dielectric for future silicon technology devices. A high dielectric constant of ∼20 and very low dielectric loss of ∼0.1% are temperature and voltage independent at 100 kHz near ambient conditions. The Pt/HHO/Pt capacitor exhibits exceptionally low Schottky emission-based leakage currents. In combination with the large observed bandgap E{sub g} of 5.6 eV, determined by diffuse reflectance spectroscopy, our results reveal fundamental physics and materials science of the HHO metal oxide and its potential application as a high-k dielectric for the next generation of complementary metal-oxide-semiconductor devices.

  8. Activation analysis of biological materials at the Activation Analysis Centre

    International Nuclear Information System (INIS)

    Kukula, F.; Obrusnik, I.; Simkova, M.; Kucera, J.; Krivanek, M.

    1976-01-01

    A review is presented of the work of the Activation Analysis Centre of the Nuclear Research Institute for different fields of the Czechoslovak economy, aimed primarily at analyzing biological materials with the purpose of determining the contents of the so-called vital trace elements and of elements which already have a toxic effect on the organism in trace concentrations. Another important field of research is the path of trace elements from the environment to the human organism. A destructive method for the simultaneous determination of 12 trace elements in 11 kinds of human tissue has been studied. (Z.M.)

  9. Japanese tea leaves: a possible biological standard reference material

    International Nuclear Information System (INIS)

    Fuwa, Keiichiro; Notsu, Kenji; Tsunoda, Kin-ichi; Kato, Hideaki; Yamamoto, Yuko.

    1978-01-01

    Japanese Tea Leaves, prepared by pulverizing with an agate ball mill and sieving with a Saran fiber sieve (50 mesh) were assessed as a possible biological standard reference material for elemental analysis. The metal content of the tea leaves was determined independently at two laboratories using atomic absorption and flame emission spectrometry. Neutron activation analysis was also performed to determine the content (21 elements) of Tea Leaves. For some elements the result from the various methods were compared. The characteristics of Tea Leaves are discussed and the elemental composition is compared to that of Orchard Leaves (NBS SRM, 1571). The most significant characteristic of Tea Leaves was the high manganese content. (auth.)

  10. Biological Applications and Transmission Electron Microscopy Investigations of Mesoporous Silica Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Trewyn, Brian G. [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    The research presented and discussed within involves the development of novel biological applications of mesoporous silica nanoparticles (MSN) and an investigation of mesoporous material by transmission electron microscopy (TEM). Mesoporous silica nanoparticles organically functionalized shown to undergo endocytosis in cancer cells and drug release from the pores was controlled intracellularly and intercellularly. Transmission electron microscopy investigations demonstrated the variety of morphologies produced in this field of mesoporous silica nanomaterial synthesis. A series of room-temperature ionic liquid (RTIL) containing mesoporous silica nanoparticle (MSN) materials with various particle morphologies, including spheres, ellipsoids, rods, and tubes, were synthesized. By changing the RTIL template, the pore morphology was tuned from the MCM-41 type of hexagonal mesopores to rotational moire type of helical channels, and to wormhole-like porous structures. These materials were used as controlled release delivery nanodevices to deliver antibacterial ionic liquids against Escherichia coli K12. The involvement of a specific organosiloxane function group, covalently attached to the exterior of fluorescein doped mesoporous silica nanoparticles (FITC-MSN), on the degree and kinetics of endocytosis in cancer and plant cells was investigated. The kinetics of endocystosis of TEG coated FITC-MSN is significantly quicker than FITC-MSN as determined by flow cytometry experiments. The fluorescence confocal microscopy investigation showed the endocytosis of TEG coated-FITC MSN triethylene glycol grafted fluorescein doped MSN (TEG coated-FITC MSN) into both KeLa cells and Tobacco root protoplasts. Once the synthesis of a controlled-release delivery system based on MCM-41-type mesoporous silica nanorods capped by disulfide bonds with superparamagnetic iron oxide nanoparticles was completed. The material was characterized by general methods and the dosage and kinetics of the

  11. Electronic processes in non-crystalline materials

    CERN Document Server

    Mott, Nevill Francis

    2012-01-01

    Since the first edition of this highly successful book the field saw many great developments both in experimental and theoretical studies of electrical properties of non-crystalline solids. It became necessary to rewrite nearly the whole book, while the aims of the second edition remained the same: to set out the theoretical concepts, to test them by comparison with experiment for a wide variety of phenomena, and to apply them to non-crystalline materials. Sir Nevill Mott shared the1977 Nobel Prize for Physics, awarded for his research work in this field. The reissue of this book as part of th

  12. Molecular modeling and multiscaling issues for electronic material applications

    CERN Document Server

    Iwamoto, Nancy; Yuen, Matthew; Fan, Haibo

    Volume 1 : Molecular Modeling and Multiscaling Issues for Electronic Material Applications provides a snapshot on the progression of molecular modeling in the electronics industry and how molecular modeling is currently being used to understand material performance to solve relevant issues in this field. This book is intended to introduce the reader to the evolving role of molecular modeling, especially seen through the eyes of the IEEE community involved in material modeling for electronic applications.  Part I presents  the role that quantum mechanics can play in performance prediction, such as properties dependent upon electronic structure, but also shows examples how molecular models may be used in performance diagnostics, especially when chemistry is part of the performance issue.  Part II gives examples of large-scale atomistic methods in material failure and shows several examples of transitioning between grain boundary simulations (on the atomistic level)and large-scale models including an example ...

  13. Materials Meets Concepts in Molecule-Based Electronics

    KAUST Repository

    Ortmann, Frank; Radke, K. Sebastian; Gü nther, Alrun; Kasemann, Daniel; Leo, Karl; Cuniberti, Gianaurelio

    2014-01-01

    In this contribution, molecular materials are highlighted as an important topic in the diverse field of condensed matter physics, with focus on their particular electronic and transport properties. A better understanding of their performance

  14. Monte Carlo calculations of electron diffusion in materials

    International Nuclear Information System (INIS)

    Schroeder, U.G.

    1976-01-01

    By means of simulated experiments, various transport problems for 10 Mev electrons are investigated. For this purpose, a special Monte-Carlo programme is developed, and with this programme calculations are made for several material arrangements. (orig./LN) [de

  15. A national facility for biological cryo-electron microscopy.

    Science.gov (United States)

    Saibil, Helen R; Grünewald, Kay; Stuart, David I

    2015-01-01

    Three-dimensional electron microscopy is an enormously powerful tool for structural biologists. It is now able to provide an understanding of the molecular machinery of cells, disease processes and the actions of pathogenic organisms from atomic detail through to the cellular context. However, cutting-edge research in this field requires very substantial resources for equipment, infrastructure and expertise. Here, a brief overview is provided of the plans for a UK national three-dimensional electron-microscopy facility for integrated structural biology to enable internationally leading research on the machinery of life. State-of-the-art equipment operated with expert support will be provided, optimized for both atomic-level single-particle analysis of purified macromolecules and complexes and for tomography of cell sections. The access to and organization of the facility will be modelled on the highly successful macromolecular crystallography (MX) synchrotron beamlines, and will be embedded at the Diamond Light Source, facilitating the development of user-friendly workflows providing near-real-time experimental feedback.

  16. New electron microprobe for radioactive materials

    International Nuclear Information System (INIS)

    Perrot, M.; Geoffroy, G.; Trotabas, M.

    1989-01-01

    The latest model of CAMECA microprobe SX 50R has just been set up in the high activity laboratory of the Centre d'Etudes Nucleaires de SACLAY. It has been especially designed for the examination of nuclear fuel and irradiated materials. The spectrometers are protected from the radioactivity by an armour plate and the entire equipment has been installed into a special cell in order to protect the operators. The special sample holder allows to examine specimens as large as 80 mm in diameter. One of the interesting uses concerns the quantitative determination of the oxygen content in zircaloy oxidized by steam at high temperature. This analysis was made possible by using the new type of crystals (multilayer)

  17. Micro-buckling in the nanocomposite structure of biological materials

    Science.gov (United States)

    Su, Yewang; Ji, Baohua; Hwang, Keh-Chih; Huang, Yonggang

    2012-10-01

    Nanocomposite structure, consisting of hard mineral and soft protein, is the elementary building block of biological materials, where the mineral crystals are arranged in a staggered manner in protein matrix. This special alignment of mineral is supposed to be crucial to the structural stability of the biological materials under compressive load, but the underlying mechanism is not yet clear. In this study, we performed analytical analysis on the buckling strength of the nanocomposite structure by explicitly considering the staggered alignment of the mineral crystals, as well as the coordination among the minerals during the buckling deformation. Two local buckling modes of the nanostructure were identified, i.e., the symmetric mode and anti-symmetric mode. We showed that the symmetric mode often happens at large aspect ratio and large volume fraction of mineral, while the anti-symmetric happens at small aspect ratio and small volume fraction. In addition, we showed that because of the coordination of minerals with the help of their staggered alignment, the buckling strength of these two modes approached to that of the ideally continuous fiber reinforced composites at large aspect ratio given by Rosen's model, insensitive to the existing "gap"-like flaws between mineral tips. Furthermore, we identified a mechanism of buckling mode transition from local to global buckling with increase of aspect ratio, which was attributed to the biphasic dependence of the buckling strength on the aspect ratio. That is, for small aspect ratio, the local buckling strength is smaller than that of global buckling so that it dominates the buckling behavior of the nanocomposite; for comparatively larger aspect ratio, the local buckling strength is higher than that of global buckling so that the global buckling dominates the buckling behavior. We also found that the hierarchical structure can effectively enhance the buckling strength, particularly, this structural design enables

  18. Nuclear, biological and chemical contamination survivability of Army material

    International Nuclear Information System (INIS)

    Feeney, J.J.

    1987-01-01

    Army Regulation (AR) 70-71, Nuclear, Biological and Chemical (NBC) Contamination Survivability of Army Material, published during 1984, establishes Army policy and procedures for the development and acquisition of material to ensure its survivablility and sustainability on the NBC-contaminated battlefield. This regulation defines NBC contamination as a term that includes both the individual and collective effects of residual radiological, biological, and chemical contamination. AR 70-71 applies to all mission-essential equipment within the Army. NBC contamination survivability is the capability of a system and its crew to withstand an NBC-contaminated environment, including decontamination, without losing the ability to accomplish the assigned mission. Characteristics of NBC contamination survivability are decontaminability, hardness, and compatability. These characteristics are engineering design criteria which are intended for use only in a developmental setting. To comply with AR 70-71, each mission-essential item must address all three criteria. The Department of Defense (DOD) has published a draft instruction addressing acquisition of NBC contamination survivable systems. This instruction will apply throughout DOD to those programs, systems and subsystems designated by the Secretary of Defense as major systems acquisition programs and to those non-major systems that have potential impact on critical functions

  19. Fluorine determinations in biological materials by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Demiralp, R.; Guinn, V.P.; Becker, D.A.

    1992-01-01

    Exploratory studies were carried out at the University of California, Irvine on several freeze-dried human diet materials and on two freeze-dried vegetation materials - all prospective reference materials. The University of California, Irvine equipment includes a 250-kW TRIGA Mark 1 reactor, 2.5 x 10 12 n/cm 2 ·s thermal flux, 3-s sample transfer time, and a typical 18% Ge(Li)/4,096-channel gamma-ray spectrometer with a detector resolution of 3.3 keV at 1,332 keV. In these exploratory studies, it was found that it was not feasible to measure fluorine with adequate precision or accuracy at fluorine concentrations much less than ∼100 ppm. These initial studies, however, defined the magnitudes of the various difficulties. One good outcome of these studies was the demonstration that the otherwise excellent Teflon-mill brittle-fracture method for homogenizing freeze-dried biological samples was not suitable if fluorine was to be determined. Abrasion of the Teflon increased the fluorine content of a human diet sample about sevenfold (compared with similar treatment of the same material in an all-titanium mill)

  20. Nature-Inspired Structural Materials for Flexible Electronic Devices.

    Science.gov (United States)

    Liu, Yaqing; He, Ke; Chen, Geng; Leow, Wan Ru; Chen, Xiaodong

    2017-10-25

    Exciting advancements have been made in the field of flexible electronic devices in the last two decades and will certainly lead to a revolution in peoples' lives in the future. However, because of the poor sustainability of the active materials in complex stress environments, new requirements have been adopted for the construction of flexible devices. Thus, hierarchical architectures in natural materials, which have developed various environment-adapted structures and materials through natural selection, can serve as guides to solve the limitations of materials and engineering techniques. This review covers the smart designs of structural materials inspired by natural materials and their utility in the construction of flexible devices. First, we summarize structural materials that accommodate mechanical deformations, which is the fundamental requirement for flexible devices to work properly in complex environments. Second, we discuss the functionalities of flexible devices induced by nature-inspired structural materials, including mechanical sensing, energy harvesting, physically interacting, and so on. Finally, we provide a perspective on newly developed structural materials and their potential applications in future flexible devices, as well as frontier strategies for biomimetic functions. These analyses and summaries are valuable for a systematic understanding of structural materials in electronic devices and will serve as inspirations for smart designs in flexible electronics.

  1. Evaluation on electrical resistivity of silicon materials after electron ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 38; Issue 5. Evaluation on ... This research deals with the study of electron beam melting (EBM) methodology utilized in melting silicon material and subsequently discusses on the effect of oxygen level on electrical resistivity change after EBM process. The oxygen ...

  2. 2D Dirac electrons in 3D materials

    NARCIS (Netherlands)

    Ramankutty, S.V.

    2018-01-01

    Quantum materials pack the spooky properties of quantum mechanics into real-life materials you can make, pick up with tweezers and study in the lab. Those of interest to us show special electronic properties of great fundamental interest and have applications potential for future computer and

  3. The role of defects on electron behavior in graphene materials

    NARCIS (Netherlands)

    Cervenka, J.

    2009-01-01

    Graphene-based materials exhibit many unique physical properties that are intriguing for both fundamental science and application purposes. This thesis describes three systems of sp2 bonded carbon: graphite, graphene and fullerene, and studies the electron behavior in these materials and how it is

  4. Soft electron processor for surface sterilization of food material

    International Nuclear Information System (INIS)

    Baba, Takashi; Kaneko, Hiromi; Taniguchi, Shuichi

    2004-01-01

    As frozen or chilled foods have become popular nowadays, it has become very important to provide raw materials with lower level microbial contamination to food processing companies. Consequently, the sterilization of food material is one of the major topics for food processing. Dried materials like grains, beans and spices, etc., are not typically deeply contaminated by microorganisms, which reside on the surfaces of materials, so it is very useful to take low energetic, lower than 300 keV, electrons with small penetration power (Soft-Electrons), as a sterilization method for such materials. Soft-Electrons is researched and named by Dr. Hayashi et al. This is a non-thermal method, so one can keep foods hygienic without serious deterioration. It is also a physical method, so is free from residues of chemicals in foods. Recently, Nissin-High Voltage Co., Ltd. have developed and manufactured equipment for commercial use of Soft-Electrons (Soft Electron Processor), which can process 500 kg/h of grains. This report introduces the Soft Electron Processor and shows the results of sterilization of wheat and brown rice by the equipment

  5. Application of electron irradiation to food containers and packaging materials

    International Nuclear Information System (INIS)

    Ueno, Koji

    2010-01-01

    Problems caused by microbial contamination and hazardous chemicals have attracted much attention in the food industry. The number of systems such as hygienic management systems and Hazard Analysis Critical Control Point (HACCP) systems adopted in the manufacturing process is increasing. As manufacturing process control has become stricter, stricter control is also required for microbial control for containers and packaging materials (from disinfection to sterilization). Since safe and reliable methods for sterilizing food containers and packaging materials that leave no residue are required, electron beam sterilization used for medical equipment has attracted attention from the food industry. This paper describes an electron irradiation facility, methods for applying electron beams to food containers and packaging materials, and products irradiated with electron beams. (author)

  6. Surface and Interface Physics of Correlated Electron Materials

    Energy Technology Data Exchange (ETDEWEB)

    Millis, Andrew [Columbia Univ., New York, NY (United States)

    2004-09-01

    The {\\it Surface and Interface Physics of Correlated Electron Materials} research program provided conceptual understanding of and theoretical methodologies for understanding the properties of surfaces and interfaces involving materials exhibiting strong electronic correlations. The issues addressed in this research program are important for basic science, because the behavior of correlated electron superlattices is a crucial challenge to and crucial test of our understanding of the grand-challenge problem of correlated electron physics and are important for our nation's energy future because correlated interfaces offer opportunities for the control of phenomena needed for energy and device applications. Results include new physics insights, development of new methods, and new predictions for materials properties.

  7. Nanodiamond composite as a material for cold electron emitters

    International Nuclear Information System (INIS)

    Arkhipov, A V; Sominski, G G; Uvarov, A A; Gordeev, S K; Korchagina, S B

    2008-01-01

    Characteristics of field-induced electron emission were investigated for one of newly designed all-carbon materials - nanodiamond composite (NDC). The composite is comprised by 4-6 nm diamond grains covered with 0.2-1 nm-thick graphite-like shells that merge at grain junctions and determine such properties as mechanical strength and high electric conductivity. Large number of uniformly distributed sp 3 -sp 2 interfaces allowed to expect enhanced electron emission in electric field. Combination of these features makes NDC a promising material for cold electron emitters in various applications. Experimental testing confirmed high efficiency of electron emission from NDC. In comparison with previousely tested forms of nanocarbon, NDC emitters demonstrated better stabily and tolerance to performance conditions. Unusual activation scenarios and thermal dependencies of emission characteristics observed in experiments with NDC can add new background for explanation of facilitated electron emission from nanocarbons with relatively 'smooth' surface morphology

  8. Nanodiamond composite as a material for cold electron emitters

    Energy Technology Data Exchange (ETDEWEB)

    Arkhipov, A V; Sominski, G G; Uvarov, A A [St.Petersburg State Polytechnic University, 29 Politchnicheskaya, St.Petersburg, 195251 (Russian Federation); Gordeev, S K; Korchagina, S B [FSUE ' Central Research Institute for Materials' , 8 Paradnaya Street, St.Petersburg, 191014 (Russian Federation)], E-mail: arkhipov@rphf.spbstu.ru

    2008-03-15

    Characteristics of field-induced electron emission were investigated for one of newly designed all-carbon materials - nanodiamond composite (NDC). The composite is comprised by 4-6 nm diamond grains covered with 0.2-1 nm-thick graphite-like shells that merge at grain junctions and determine such properties as mechanical strength and high electric conductivity. Large number of uniformly distributed sp{sup 3}-sp{sup 2} interfaces allowed to expect enhanced electron emission in electric field. Combination of these features makes NDC a promising material for cold electron emitters in various applications. Experimental testing confirmed high efficiency of electron emission from NDC. In comparison with previousely tested forms of nanocarbon, NDC emitters demonstrated better stabily and tolerance to performance conditions. Unusual activation scenarios and thermal dependencies of emission characteristics observed in experiments with NDC can add new background for explanation of facilitated electron emission from nanocarbons with relatively 'smooth' surface morphology.

  9. Electron reactions in model liquids and biological systems

    International Nuclear Information System (INIS)

    Bakale, G.; Gregg, E.C.

    1982-01-01

    Progress is reported in the following studies: (1) Field-dependent electron attachment; (2) Dependence of electron attachment rate on electron-acceptor dipole moment; (3) Electron attachment in i-octane/TMS mixtures; (4) Electron attachment/detachment equilibria; (5) Electron attachment to reversed micelles; (6) Electron attachment to chemical carcinogens; (7) Radiation-induced bacterial mutagenesis; and (8) Bacterial mutagenicity of nitrobenzene derivatives. 14 references

  10. Student decisions about lecture attendance: do electronic course materials matter?

    Science.gov (United States)

    Billings-Gagliardi, Susan; Mazor, Kathleen M

    2007-10-01

    This study explored whether first-year medical students make deliberate decisions about attending nonrequired lectures. If so, it sought to identify factors that influence these decisions, specifically addressing the potential impact of electronic materials. Medical students who completed first-year studies between 2004 and 2006 responded to an open-ended survey question about their own lecture-attendance decisions. Responses were coded to capture major themes. Students' ratings of the electronic materials were also examined. Most respondents made deliberate attendance decisions. Decisions were influenced by previous experiences with the lecturer, predictions of what would occur during the session itself, personal learning preferences, and learning needs at that particular time, with the overriding goal of maximizing learning. Access to electronic materials did not influence students' choices. Fears that the increasing availability of technology-enhanced educational materials has a negative impact on lecture attendance seem unfounded.

  11. Electrons scattered inside small dust grains of various materials

    International Nuclear Information System (INIS)

    Richterova, Ivana; Beranek, Martin; Pavlu, Jiri; Nemecek, Zdenek; Safrankova, Jana

    2010-01-01

    The dust grain charge in an electron beam is given by a difference in numbers of electrons that fall onto the grain and those leaving it. Electrons with energies exceeding 1 keV can penetrate through submicron-sized dust grains. If the grain is small enough, a yield of these electrons reaches unity but they leave a part of their energy inside the grain and this energy excites secondary electrons. The paper presents a hybrid Monte Carlo code that simulates paths of the primary electrons inside a spherical grain and provides the yield of scattered electrons and their energy spectrum as a function of the grain size and material. This code is based on the Richterovaet al. [Phys. Rev. B 74, 235430 (2006)] model but it includes several corrections important for light materials like carbon or ice. The model was verified using experimental results obtained on large planar samples. For spherical samples, we have found that the yield of scattered electrons reaches unity for 50 nm Au grains illuminated by 5 keV electrons, whereas the same effect can be observed on ≅1000 nm carbon grains.

  12. Electron energy loss spectroscopy microanalysis and imaging in the transmission electron microscope: example of biological applications

    International Nuclear Information System (INIS)

    Diociaiuti, Marco

    2005-01-01

    This paper reports original results obtained in our laboratory over the past few years in the application of both electron energy loss spectroscopy (EELS) and electron spectroscopy imaging (ESI) to biological samples, performed in two transmission electron microscopes (TEM) equipped with high-resolution electron filters and spectrometers: a Gatan model 607 single magnetic sector double focusing EEL serial spectrometer attached to a Philips 430 TEM and a Zeiss EM902 Energy Filtering TEM. The primary interest was on the possibility offered by the combined application of these spectroscopic techniques with those offered by the TEM. In particular, the electron beam focusing available in a TEM allowed us to perform EELS and ESI on very small sample volumes, where high-resolution imaging and electron diffraction techniques can provide important structural information. I show that ESI was able to improve TEM performance, due to the reduced chromatic aberration and the possibility of avoiding the sample staining procedure. Finally, the analysis of the oscillating extended energy loss fine structure (EXELFS) beyond the ionization edges characterizing the EELS spectra allowed me, in a manner very similar to the extended X-ray absorption fine structure (EXAFS) analysis of the X-ray absorption spectra, to obtain short-range structural information for such light elements of biological interest as O or Fe. The Philips EM430 (250-300 keV) TEM was used to perform EELS microanalysis on Ca, P, O, Fe, Al and Si. The assessment of the detection limits of this method was obtained working with well-characterized samples containing Ca and P, and mimicking the actual cellular matrix. I applied EELS microanalysis to Ca detection in bone tissue during the mineralization process and to P detection in the cellular membrane of erythrocytes treated with an anti-tumoral drug, demonstrating that the cellular membrane is a drug target. I applied EELS microanalysis and selected area electron

  13. Urban Biomining Meets Printable Electronics: End-To-End at Destination Biological Recycling and Reprinting

    Science.gov (United States)

    Rothschild, Lynn J. (Principal Investigator); Koehne, Jessica; Gandhiraman, Ram; Navarrete, Jesica; Spangle, Dylan

    2017-01-01

    Space missions rely utterly on metallic components, from the spacecraft to electronics. Yet, metals add mass, and electronics have the additional problem of a limited lifespan. Thus, current mission architectures must compensate for replacement. In space, spent electronics are discarded; on earth, there is some recycling but current processes are toxic and environmentally hazardous. Imagine instead an end-to-end recycling of spent electronics at low mass, low cost, room temperature, and in a non-toxic manner. Here, we propose a solution that will not only enhance mission success by decreasing upmass and providing a fresh supply of electronics, but in addition has immediate applications to a serious environmental issue on the Earth. Spent electronics will be used as feedstock to make fresh electronic components, a process we will accomplish with so-called 'urban biomining' using synthetically enhanced microbes to bind metals with elemental specificity. To create new electronics, the microbes will be used as 'bioink' to print a new IC chip, using plasma jet electronics printing. The plasma jet electronics printing technology will have the potential to use martian atmospheric gas to print and to tailor the electronic and chemical properties of the materials. Our preliminary results have suggested that this process also serves as a purification step to enhance the proportion of metals in the 'bioink'. The presence of electric field and plasma can ensure printing in microgravity environment while also providing material morphology and electronic structure tunabiity and thus optimization. Here we propose to increase the TRL level of the concept by engineering microbes to dissolve the siliceous matrix in the IC, extract copper from a mixture of metals, and use the microbes as feedstock to print interconnects using mars gas simulant. To assess the ability of this concept to influence mission architecture, we will do an analysis of the infrastructure required to execute

  14. [Multi-causality in nursing work accidents with biological material].

    Science.gov (United States)

    Soares, Leticia Gramazio; Sarquis, Leila Maria Mansano; Kirchhof, Ana Lúcia Cardoso; Felli, Vanda Elisa Andres

    2013-12-01

    In order to analyze the multiple causes of occupational accidents with biological exposure among nursing staff was carried out a descriptive and exploratory research in a medium-sized hospital in the State of Paraná, in the period between January 2008 and January 2009. The population was 26 nursing staff of the medical clinic. Data collection was performed by semi-structured interviews with five of the eight injured in the period and its contents were analyzed by Causes and Effects Diagram. The categories of causes material, organizational, institutional and worker's behavior, showed the inappropriate disposal of sharps, work overload, no use of bio-security standards and poor supervision and training of workers, as factors for the occurrence of these accidents. The adoption of the tool of Causes and Effects Diagram provided an analysis of accidents in its multiple causes, showing the interaction between them.

  15. Problems in the determination of chromium in biological materials

    International Nuclear Information System (INIS)

    Behne, D.; Braetter, P.; Gessner, H.; Hube, G.; Mertz, W.; Roesick, U.

    1976-01-01

    The effects of sample preparation on the analysis of chromium in biological matter have been investigated using brewer's yeast as a test material. The apparent chromium content of the yeast as determined by flameless atomic absorption spectrometry was significantly higher after destruction of the organic matter with HNO 3 in a closed pressure vessel than after wet-ashing in open vessels and after direct introduction of the sample into the graphite furnace. The results obtained by neutron activation analysis without any sample preparation, which corresponded to the atomic absorption values after digestion in the pressure vessel, showed that considerable errors arise in the other methods of sample treatment. Chromium analysis of dried and ashed yeast suggest that losses of volatile chromium compounds may occur during heating. (orig.) [de

  16. [Accidents with biological material at West Paraná University Hospital].

    Science.gov (United States)

    Murofuse, Neide Tiemi; Marziale, Maria Helena Palucci; Gemelli, Lorena Moraes Goetem

    2005-08-01

    It is a descriptive and retrospective study with the purpose of investigating labor accidents with biological material involving workers and trainees occurred in 2003 and 2004 in a University Hospital of Parana. For data collection, the electronic form of the Net of Occupational Accidents Prevention - REPAT has been utilized. Out of the 586 hospital workers, there was a register of 20 (3,4%) injured workers in 2003 and 23 (3,8%) in 2004, representing an increase of 15% in the notifications from one year to the other.

  17. The High-Strain Rate Loading of Structural Biological Materials

    Science.gov (United States)

    Proud, W. G.; Nguyen, T.-T. N.; Bo, C.; Butler, B. J.; Boddy, R. L.; Williams, A.; Masouros, S.; Brown, K. A.

    2015-10-01

    The human body can be subjected to violent acceleration as a result of explosion caused by military ordinance or accident. Blast waves cause injury and blunt trauma can be produced by violent impact of objects against the human body. The long-term clinical manifestations of blast injury can be significantly different in nature and extent to those suffering less aggressive insult. Similarly, the damage seen in lower limbs from those injured in explosion incidents is in general more severe than those falling from height. These phenomena increase the need for knowledge of the short- and long-term effect of transient mechanical loading to the biological structures of the human body. This paper gives an overview of some of the results of collaborative investigation into blast injury. The requirement for time-resolved data, appropriate mechanical modeling, materials characterization and biological effects is presented. The use of a range of loading platforms, universal testing machines, drop weights, Hopkinson bars, and bespoke traumatic injury simulators are given.

  18. Ion beam modification of biological materials in nanoscale

    Science.gov (United States)

    Yu, L. D.; Anuntalabhochai, S.

    2012-07-01

    Ion interaction with biological objects in nanoscale is a novel research area stemming from applications of low-energy ion beams in biotechnology and biomedicine. Although the ion beam applications in biotechnology and biomedicine have achieved great successes, many mechanisms remain unclear and many new applications are to be explored. We have carried out some research on exploring the mechanisms and new applications besides attaining ion beam induction of mutation breeding and gene transformation. In the studies on the mechanisms, we focused our investigations on the direct interaction in nanoscale between ions and biological living materials. Our research topics have included the low-energy ion range in DNA, low-energy ion or neutral beam bombardment effect on DNA topological form change and mutation, low-energy ion or neutral beam bombardment effect on the cell envelope and gene transformation, and molecular dynamics simulation of ultra-low-energy ion irradiation of DNA. In the exploration of new applications, we have started experiments on ion irradiation or bombardment, in the nanoscaled depth or area, of human cells for biomedical research. This paper introduces our experiments and reports interesting results.

  19. Ion beam modification of biological materials in nanoscale

    International Nuclear Information System (INIS)

    Yu, L.D.; Anuntalabhochai, S.

    2012-01-01

    Ion interaction with biological objects in nanoscale is a novel research area stemming from applications of low-energy ion beams in biotechnology and biomedicine. Although the ion beam applications in biotechnology and biomedicine have achieved great successes, many mechanisms remain unclear and many new applications are to be explored. We have carried out some research on exploring the mechanisms and new applications besides attaining ion beam induction of mutation breeding and gene transformation. In the studies on the mechanisms, we focused our investigations on the direct interaction in nanoscale between ions and biological living materials. Our research topics have included the low-energy ion range in DNA, low-energy ion or neutral beam bombardment effect on DNA topological form change and mutation, low-energy ion or neutral beam bombardment effect on the cell envelope and gene transformation, and molecular dynamics simulation of ultra-low-energy ion irradiation of DNA. In the exploration of new applications, we have started experiments on ion irradiation or bombardment, in the nanoscaled depth or area, of human cells for biomedical research. This paper introduces our experiments and reports interesting results.

  20. Introduction to organic electronic and optoelectronic materials and devices

    CERN Document Server

    Sun, Sam-Shajing

    2008-01-01

    Introduction to Optoelectronic Materials, N. Peyghambarian and M. Fallahi Introduction to Optoelectronic Device Principles, J. Piprek Basic Electronic Structures and Charge Carrier Generation in Organic Optoelectronic Materials, S.-S. Sun Charge Transport in Conducting Polymers, V.N. Prigodin and A.J. Epstein Major Classes of Organic Small Molecules for Electronic and Optoelectronics, X. Meng, W. Zhu, and H. Tian Major Classes of Conjugated Polymers and Synthetic Strategies, Y. Li and J. Hou Low Energy Gap, Conducting, and Transparent Polymers, A. Kumar, Y. Ner, and G.A. Sotzing Conjugated Polymers, Fullerene C60, and Carbon Nanotubes for Optoelectronic Devices, L. Qu, L. Dai, and S.-S. Sun Introduction of Organic Superconducting Materials, H. Mori Molecular Semiconductors for Organic Field-Effect Transistors, A. Facchetti Polymer Field-Effect Transistors, H.G.O. Sandberg Organic Molecular Light-Emitting Materials and Devices, F. So and J. Shi Polymer Light-Emitting Diodes: Devices and Materials, X. Gong and ...

  1. Millimeter wave and terahertz dielectric properties of biological materials

    Science.gov (United States)

    Khan, Usman Ansar

    Broadband dielectric properties of materials can be employed to identify, detect, and characterize materials through their unique spectral signatures. In this study, millimeter wave, submillimeter wave, and terahertz dielectric properties of biological substances inclusive of liquids, solids, and powders were obtained using Dispersive Fourier Transform Spectroscopy (DFTS). Two broadband polarizing interferometers were constructed to test materials from 60 GHz to 1.2 THz. This is an extremely difficult portion of the frequency spectrum to obtain a material's dielectric properties since neither optical nor microwave-based techniques provide accurate data. The dielectric characteristics of liquids such as cyclohexane, chlorobenzene, benzene, ethanol, methanol, 1,4 dioxane, and 10% formalin were obtained using the liquid interferometer. Subsequently the solid interferometer was utilized to determine the dielectric properties of human breast tissues, which are fixed and preserved in 10% formalin. This joint collaboration with the Tufts New England Medical Center demonstrated a significant difference between the dielectric response of tumorous and non-tumorous breast tissues across the spectrum. Powders such as anthrax, flour, talc, corn starch, dry milk, and baking soda have been involved in a number of security threats and false alarms around the globe in the last decade. To be able to differentiate hoax attacks and serious security threats, the dielectric properties of common household powders were also examined using the solid interferometer to identify the powders' unique resonance peaks. A new sample preparation kit was designed to test the powder specimens. It was anticipated that millimeter wave and terahertz dielectric characterization will enable one to clearly distinguish one powder from the other; however most of the powders had relatively close dielectric responses and only Talc had a resonance signature recorded at 1.135 THz. Furthermore, due to

  2. Ultrastable gold substrates: Properties of a support for high-resolution electron cryomicroscopy of biological specimens

    Science.gov (United States)

    Russo, Christopher J.; Passmore, Lori A.

    2016-01-01

    Electron cryomicroscopy (cryo-EM) allows structure determination of a wide range of biological molecules and specimens. All-gold supports improve cryo-EM images by reducing radiation-induced motion and image blurring. Here we compare the mechanical and electrical properties of all-gold supports to amorphous carbon foils. Gold supports are more conductive, and have suspended foils that are not compressed by differential contraction when cooled to liquid nitrogen temperatures. These measurements show how the choice of support material and geometry can reduce specimen movement by more than an order of magnitude during low-dose imaging. We provide methods for fabrication of all-gold supports and preparation of vitrified specimens. We also analyse illumination geometry for optimal collection of high resolution, low-dose data. Together, the support structures and methods herein can improve the resolution and quality of images from any electron cryomicroscope. PMID:26592474

  3. Materials and Reliability Handbook for Semiconductor Optical and Electron Devices

    CERN Document Server

    Pearton, Stephen

    2013-01-01

    Materials and Reliability Handbook for Semiconductor Optical and Electron Devices provides comprehensive coverage of reliability procedures and approaches for electron and photonic devices. These include lasers and high speed electronics used in cell phones, satellites, data transmission systems and displays. Lifetime predictions for compound semiconductor devices are notoriously inaccurate due to the absence of standard protocols. Manufacturers have relied on extrapolation back to room temperature of accelerated testing at elevated temperature. This technique fails for scaled, high current density devices. Device failure is driven by electric field or current mechanisms or low activation energy processes that are masked by other mechanisms at high temperature. The Handbook addresses reliability engineering for III-V devices, including materials and electrical characterization, reliability testing, and electronic characterization. These are used to develop new simulation technologies for device operation and ...

  4. Consensus values for NIST biological and environmental Standard Reference Materials

    International Nuclear Information System (INIS)

    Roelandts, I.; Gladney, E.S.

    1998-01-01

    The National Institute of Standards and Technology (NIST, formerly the National Bureau of Standards or NBS) has produced numerous Standard Reference Materials (SRM) for use in biological and environmental analytical chemistry. The value listed on the ''NIST Certificate of Analysis'' is the present best estimate of the ''true'' concentration of that element and is not expected to deviate from that concentration by more than the stated uncertainty. However, NIST does not certify the elemental concentration of every constituent and the number of elements reported in the NIST programs tends to be limited.Numerous analysts have published concentration data on these reference materials. Major journals in analytical chemistry, books, proceedings and ''technical reports'' have been surveyed to collect these available literature values. A standard statistical approach has been employed to evaluate the compiled data. Our methodology has been developed in a series of previous papers. Some subjective criteria are first used to reject aberrant data. Following these eliminations, an initial arithmetic mean and standard deviation (S.D.) are computed from remaining data for each element. All data now outside two S.D. from the initial mean are dropped and a second mean and S.D. recalculated. These final means and associated S.D. are reported as ''consensus values'' in our tables. (orig.)

  5. Electronic and Ionic Conductors from Ordered Microporous Materials

    Energy Technology Data Exchange (ETDEWEB)

    Dincă, Mircea [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2017-10-30

    The proposed work aimed to establish metal-organic frameworks (MOFs) as new classes of high-surface area microporous electronic and ionic conductors. MOFs are crystalline materials with pore sizes ranging from 0.2 to ~ 2 nm (or larger for the latter) defined by inorganic or organic building blocks connected by rigid organic linkers. Myriad applications have been found or proposed for these materials, yet those that require electron transport or conductivity in combination with permanent porosity still lag behind because the vast majority of known frameworks are electrical insulators. Prior to our proposal and subsequent work, there were virtually no studies exploring the possibility of electronic delocalization in these materials. Therefore, our primary goal was to understand and control, at a fundamental level, the electron and ion transport properties of this class of materials, with no specific application proposed, although myriad applications could be envisioned for high surface area conductors. Our goals directly addressed one of the DOE-identified Grand Challenges for Basic Energy Sciences: designing perfect atom- and energy-efficient syntheses of revolutionary new forms of matter with tailored properties. Indeed, the proposed work is entirely synthetic in nature; owing to the molecular nature of the building blocks in MOFs, there is the possibility of unprecedented control over the structure and properties of solid crystalline matter. The goals also tangentially addressed the Grand Challenge of controlling materials processes at the level of electrons: the scope of our program is to create new materials where charges (electrons and/or ions) move according to predefined pathways.

  6. Molecular and nanoscale materials and devices in electronics.

    Science.gov (United States)

    Fu, Lei; Cao, Lingchao; Liu, Yunqi; Zhu, Daoben

    2004-12-13

    Over the past several years, there have been many significant advances toward the realization of electronic computers integrated on the molecular scale and a much greater understanding of the types of materials that will be useful in molecular devices and their properties. It was demonstrated that individual molecules could serve as incomprehensibly tiny switch and wire one million times smaller than those on conventional silicon microchip. This has resulted very recently in the assembly and demonstration of tiny computer logic circuits built from such molecular scale devices. The purpose of this review is to provide a general introduction to molecular and nanoscale materials and devices in electronics.

  7. Application of electron and Bremsstrahlung beams for composite materials processing

    International Nuclear Information System (INIS)

    Zalyubovsky, I.I.; Avilov, A.M.; Popov, G.F.; Rudychev, V.G.

    1998-01-01

    In Kharkiv University the radiation process of obtaining composite polymer materials, CPM, with high strength properties and corrosion resistance was studied. CPM are manufactured by vacuum impregnating capillary-porous materials with synthetic monomers and oligomers or by molding granular waste and resins which are further treated by relativistic electron or Bremsstrahlung beam. Such radiation treatment yields new CPM in which capillary-porous structure acting as reinforcement is filled with polymer. The results of the applied research with industrial electron accelerator in the field of thick CPM formation are presented

  8. Protein electron transfer: is biology (thermo)dynamic?

    International Nuclear Information System (INIS)

    Matyushov, Dmitry V

    2015-01-01

    Simple physical mechanisms are behind the flow of energy in all forms of life. Energy comes to living systems through electrons occupying high-energy states, either from food (respiratory chains) or from light (photosynthesis). This energy is transformed into the cross-membrane proton-motive force that eventually drives all biochemistry of the cell. Life’s ability to transfer electrons over large distances with nearly zero loss of free energy is puzzling and has not been accomplished in synthetic systems. The focus of this review is on how this energetic efficiency is realized. General physical mechanisms and interactions that allow proteins to fold into compact water-soluble structures are also responsible for a rugged landscape of energy states and a broad distribution of relaxation times. Specific to a protein as a fluctuating thermal bath is the protein-water interface, which is heterogeneous both dynamically and structurally. The spectrum of interfacial fluctuations is a consequence of protein’s elastic flexibility combined with a high density of surface charges polarizing water dipoles into surface nanodomains. Electrostatics is critical to the protein function and the relevant questions are: (i) What is the spectrum of interfacial electrostatic fluctuations? (ii) Does the interfacial biological water produce electrostatic signatures specific to proteins? (iii) How is protein-mediated chemistry affected by electrostatics? These questions connect the fluctuation spectrum to the dynamical control of chemical reactivity, i.e. the dependence of the activation free energy of the reaction on the dynamics of the bath. Ergodicity is often broken in protein-driven reactions and thermodynamic free energies become irrelevant. Continuous ergodicity breaking in a dense spectrum of relaxation times requires using dynamically restricted ensembles to calculate statistical averages. When applied to the calculation of the rates, this formalism leads to the nonergodic

  9. Materials Meets Concepts in Molecule-Based Electronics

    KAUST Repository

    Ortmann, Frank

    2014-10-14

    In this contribution, molecular materials are highlighted as an important topic in the diverse field of condensed matter physics, with focus on their particular electronic and transport properties. A better understanding of their performance in various applications and devices demands for an extension of basic theoretical approaches to describe charge transport in molecular materials, including the accurate description of electron-phonon coupling. Starting with the simplest case of a molecular junction and moving on to larger aggregates of bulk organic semiconductors, charge-transport regimes from ballistic motion to incoherent hopping, which are frequently encountered in molecular systems under respective conditions, are discussed. Transport features of specific materials are described through ab initio material parameters whose determination is addressed. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA.

  10. Secondary Electron Emission Yields from PEP-II Accelerator Materials

    International Nuclear Information System (INIS)

    Kirby, Robert E.

    2000-01-01

    The PEP-II B-Factory at SLAC operates with aluminum alloy and copper vacuum chambers, having design positron and electron beam currents of 2 and 1 A, respectively. Titanium nitride coating of the aluminum vacuum chamber in the arcs of the positron ring is needed in order to reduce undesirable electron-cloud effects. The total secondary electron emission yield of TiN-coated aluminum alloy has been measured after samples of beam chamber material were exposed to air and again after electron-beam bombardment, as a function of incident electron beam angle and energy. The results may be used to simulate and better understand electron-cloud effects under actual operating conditions. We also present yield measurements for other accelerator materials because new surface effects are expected to arise as beam currents increase. Copper, in particular, is growing in popularity for its good thermal conductivity and self-radiation-shielding properties. The effect of electron bombardment, ''conditioning'', on the yield of TiN and copper is shown

  11. Survey of currently available reference materials for use in connection with the determination of trace elements in biological materials

    International Nuclear Information System (INIS)

    Parr, R.M.

    1983-09-01

    Elemental analysis of biological materials is at present the subject of intensive study by many different research groups throughout the world, in view of the importance of these trace elements in health and medical diagnosis. IAEA and other organizations are now making a variety of suitable reference materials available for use in connection with the determination of trace elements in biological materials. To help analysts in making a selection from among these various materials, the present report provides a brief survey of data for all such biological reference materials known to the author. These data are compiled by the author from January 1982 to June 1983

  12. Soft Active Materials for Actuation, Sensing, and Electronics

    OpenAIRE

    Kramer, Rebecca Krone

    2012-01-01

    Future generations of robots, electronics, and assistive medical devices will include systems that are soft and elastically deformable, allowing them to adapt their morphology in unstructured environments. This will require soft active materials for actuation, circuitry, and sensing of deformation and contact pressure. The emerging field of soft robotics utilizes these soft active materials to mimic the inherent compliance of natural soft-bodied systems. As the elasticity of robot components ...

  13. Cell attachment properties of Portland cement-based endodontic materials: biological and methodological considerations.

    Science.gov (United States)

    Ahmed, Hany Mohamed Aly; Luddin, Norhayati; Kannan, Thirumulu Ponnuraj; Mokhtar, Khairani Idah; Ahmad, Azlina

    2014-10-01

    The attachment and spreading of mammalian cells on endodontic biomaterials are an area of active research. The purpose of this review is to discuss the cell attachment properties of Portland cement (PC)-based materials by using scanning electron microscope (SEM). In addition, methodological aspects and technical challenges are discussed. A PubMed electronic search was conducted by using appropriate key words to identify the available investigations on the cell attachment properties of PC-based endodontic materials. After retrieving the full text of related articles, the cross citations were also identified. A total of 23 articles published between January 1993 and October 2013 were identified. This review summarizes the cell attachment properties of commercial and experimental PC-based materials on different cell cultures by using SEM. Methodological procedures, technical challenges, and relevance of SEM in determining the biological profile of PC-based materials are discussed. SEM observations demonstrate that commercial MTA formulations show favorable cell attachment properties, which is consistent with their successful clinical outcomes. The favorable cell attachment properties of PC and its modified formulations support its potential use as a substitute for mineral trioxide aggregate. However, researchers should carefully select cell types for their SEM investigations that would be in contact with the proposed PC-based combinations in the clinical situation. Despite being a technical challenge, SEM provides useful information on the cell attachment properties of PC-based materials; however, other assays for cell proliferation and viability are essential to come up with an accurate in vitro biological profile of any given PC-based formulation. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  14. Molecular depth profiling of organic and biological materials

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, John S. [Surface Analysis Research Centre, School of Chemical Engineering and Analytical Science, University of Manchester, Manchester M60 1QD (United Kingdom)]. E-mail: John.Fletcher@manchester.ac.uk; Conlan, Xavier A. [Surface Analysis Research Centre, School of Chemical Engineering and Analytical Science, University of Manchester, Manchester M60 1QD (United Kingdom); Lockyer, Nicholas P. [Surface Analysis Research Centre, School of Chemical Engineering and Analytical Science, University of Manchester, Manchester M60 1QD (United Kingdom); Vickerman, John C. [Surface Analysis Research Centre, School of Chemical Engineering and Analytical Science, University of Manchester, Manchester M60 1QD (United Kingdom)

    2006-07-30

    Atomic depth profiling using secondary ion mass spectrometry, SIMS, is common in the field micro-electronics; however, the generation of molecular information as a function of sample depth is difficult due to the accumulation of damage both on and beneath the sample surface. The introduction of polyatomic ion beams such as SF{sub 5} and C{sub 60} have raised the possibility of overcoming this problem as they deposit the majority of their energy in the upper surface of the sample resulting in increased sputter yields but with a complimentary reduction in sub-surface damage accumulation. In this paper we report the depth profile analysis of the bio-polymer polycaprolactone, PCL, using the polyatomic ions Au{sub 3}{sup +} and C{sub 60}{sup +} and the monoatomic Au{sup +}. Results are compared to recent analysis of a similar sample using SF{sub 5}{sup +}. C{sub 60}{sup +} depth profiling of cellulose is also demonstrated, an experiment that has been reported as unsuccessful when attempted with SF{sub 5}{sup +} implications for biological analysis are discussed.

  15. Mass determination based on electron scattering in electron probe X-ray microanalysis of thin biological specimens

    International Nuclear Information System (INIS)

    Linders, P.W.J.

    1984-01-01

    This thesis describes the development of a method for mass determination of thin biological objects by quantitative electron microscopy. The practical realization of the mass determination consists of photographical recording with subsequent densitometry. (Auth.)

  16. Electron fluence correction factors for various materials in clinical electron beams

    International Nuclear Information System (INIS)

    Olivares, M.; Blois, F. de; Podgorsak, E.B.; Seuntjens, J.P.

    2001-01-01

    Relative to solid water, electron fluence correction factors at the depth of dose maximum in bone, lung, aluminum, and copper for nominal electron beam energies of 9 MeV and 15 MeV of the Clinac 18 accelerator have been determined experimentally and by Monte Carlo calculation. Thermoluminescent dosimeters were used to measure depth doses in these materials. The measured relative dose at d max in the various materials versus that of solid water, when irradiated with the same number of monitor units, has been used to calculate the ratio of electron fluence for the various materials to that of solid water. The beams of the Clinac 18 were fully characterized using the EGS4/BEAM system. EGSnrc with the relativistic spin option turned on was used to optimize the primary electron energy at the exit window, and to calculate depth doses in the five phantom materials using the optimized phase-space data. Normalizing all depth doses to the dose maximum in solid water stopping power ratio corrected, measured depth doses and calculated depth doses differ by less than ±1% at the depth of dose maximum and by less than 4% elsewhere. Monte Carlo calculated ratios of doses in each material to dose in LiF were used to convert the TLD measurements at the dose maximum into dose at the center of the TLD in the phantom material. Fluence perturbation correction factors for a LiF TLD at the depth of dose maximum deduced from these calculations amount to less than 1% for 0.15 mm thick TLDs in low Z materials and are between 1% and 3% for TLDs in Al and Cu phantoms. Electron fluence ratios of the studied materials relative to solid water vary between 0.83±0.01 and 1.55±0.02 for materials varying in density from 0.27 g/cm3 (lung) to 8.96 g/cm3 (Cu). The difference in electron fluence ratios derived from measurements and calculations ranges from -1.6% to +0.2% at 9 MeV and from -1.9% to +0.2% at 15 MeV and is not significant at the 1σ level. Excluding the data for Cu, electron fluence

  17. Highlighting material structure with transmission electron diffraction correlation coefficient maps.

    Science.gov (United States)

    Kiss, Ákos K; Rauch, Edgar F; Lábár, János L

    2016-04-01

    Correlation coefficient maps are constructed by computing the differences between neighboring diffraction patterns collected in a transmission electron microscope in scanning mode. The maps are shown to highlight material structural features like grain boundaries, second phase particles or dislocations. The inclination of the inner crystal interfaces are directly deduced from the resulting contrast. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Decontamination of drug vegetative raw material by relativistic electron beam

    International Nuclear Information System (INIS)

    Gorbanyuk, A.G.; Dikiy, I.L.; Yegorov, A.M.; Linnik, A.F.; Uskov, V.V.

    2004-01-01

    The new technology of decontamination of drug vegetative raw material and medical products is proposed. Advantages of use of relativistic beams in a range of electron energies from 0.5 MeV to 5 MeV for these purposes are shown in comparison with X-radiation of energy from 80 keV to 1 MeV

  19. Electron Charged Graphite-based Hydrogen Storage Material

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Chinbay Q. Fan; D Manager

    2012-03-14

    The electron-charge effects have been demonstrated to enhance hydrogen storage capacity using materials which have inherent hydrogen storage capacities. A charge control agent (CCA) or a charge transfer agent (CTA) was applied to the hydrogen storage material to reduce internal discharge between particles in a Sievert volumetric test device. GTI has tested the device under (1) electrostatic charge mode; (2) ultra-capacitor mode; and (3) metal-hydride mode. GTI has also analyzed the charge distribution on storage materials. The charge control agent and charge transfer agent are needed to prevent internal charge leaks so that the hydrogen atoms can stay on the storage material. GTI has analyzed the hydrogen fueling tank structure, which contains an air or liquid heat exchange framework. The cooling structure is needed for hydrogen fueling/releasing. We found that the cooling structure could be used as electron-charged electrodes, which will exhibit a very uniform charge distribution (because the cooling system needs to remove heat uniformly). Therefore, the electron-charge concept does not have any burden of cost and weight for the hydrogen storage tank system. The energy consumption for the electron-charge enhancement method is quite low or omitted for electrostatic mode and ultra-capacitor mode in comparison of other hydrogen storage methods; however, it could be high for the battery mode.

  20. Advanced electrical and electronics materials processes and applications

    CERN Document Server

    Gupta, K M

    2015-01-01

    This comprehensive and unique book is intended to cover the vast and fast-growing field of electrical and electronic materials and their engineering in accordance with modern developments.   Basic and pre-requisite information has been included for easy transition to more complex topics. Latest developments in various fields of materials and their sciences/engineering, processing and applications have been included. Latest topics like PLZT, vacuum as insulator, fiber-optics, high temperature superconductors, smart materials, ferromagnetic semiconductors etc. are covered. Illustrations and exa

  1. Methanol as electron donor for thermophilic biological sulfate and sulfite reduction

    OpenAIRE

    Weijma, J.

    2000-01-01

    Sulfur oxyanions (e.g. sulfate, sulfite) can be removed from aqueous waste- and process streams by biological reduction with a suitable electron donor to sulfide, followed by partial chemical or biological oxidation of sulfide to elemental sulfur. The aim of the research described in this thesis was to make this biological process more broadly applicable for desulfurization of flue-gases and ground- and wastewaters by using the cheap chemical methanol as electron donor for the reduct...

  2. Electronic fitness function for screening semiconductors as thermoelectric materials

    International Nuclear Information System (INIS)

    Xing, Guangzong; Sun, Jifeng; Li, Yuwei; Fan, Xiaofeng

    2017-01-01

    Here, we introduce a simple but efficient electronic fitness function (EFF) that describes the electronic aspect of the thermoelectric performance. This EFF finds materials that overcome the inverse relationship between σ and S based on the complexity of the electronic structures regardless of specific origin (e.g., isosurface corrugation, valley degeneracy, heavy-light bands mixture, valley anisotropy or reduced dimensionality). This function is well suited for application in high throughput screening. We applied this function to 75 different thermoelectric and potential thermoelectric materials including full- and half-Heuslers, binary semiconductors, and Zintl phases. We find an efficient screening using this transport function. The EFF identifies known high-performance p- and n-type Zintl phases and half-Heuslers. In addition, we find some previously unstudied phases with superior EFF.

  3. Non-contact tensile viscoelastic characterization of microscale biological materials

    Science.gov (United States)

    Li, Yuhui; Hong, Yuan; Xu, Guang-Kui; Liu, Shaobao; Shi, Qiang; Tang, Deding; Yang, Hui; Genin, Guy M.; Lu, Tian Jian; Xu, Feng

    2018-06-01

    Many structures and materials in nature and physiology have important "meso-scale" structures at the micron length-scale whose tensile responses have proven difficult to characterize mechanically. Although techniques such as atomic force microscopy and micro- and nano-identation are mature for compression and indentation testing at the nano-scale, and standard uniaxial and shear rheometry techniques exist for the macroscale, few techniques are applicable for tensile-testing at the micrometre-scale, leaving a gap in our understanding of hierarchical biomaterials. Here, we present a novel magnetic mechanical testing (MMT) system that enables viscoelastic tensile testing at this critical length scale. The MMT system applies non-contact loading, avoiding gripping and surface interaction effects. We demonstrate application of the MMT system to the first analyses of the pure tensile responses of several native and engineered tissue systems at the mesoscale, showing the broad potential of the system for exploring micro- and meso-scale analysis of structured and hierarchical biological systems.

  4. Heavy metal ion removal by adsorption on to biological materials

    International Nuclear Information System (INIS)

    Jansson-Charrier, M.; Guibal, E.; Le Cloirec, P.; Surjous, R.

    1994-01-01

    The development of regulations constraints in the industrial waste-waters management leads to the study of new treatment processes, using raw or functionalized biological materials. These processes show competitive performances in metal ion sorption efficiency for the low metal content effluents. Uptake capacities of Uranium as high as 400 mg.g -1 chitosan, equivalent to the double of the uptake capacity of fungal origin biomass, can be reached. The application of these processes to real mine wastewaters gives efficiency coefficient upper to 90%, the residual concentrations are compatible to a direct injection into the environment. The grafting of functional groups onto the chitosan scales up the sorption performances to uptake capacity upper than 600 mg.g -1 polymer. pH, metal concentration are cited as major parameters, particle size influences both uptake kinetics and sorption equilibrium, in the case of the uranium accumulation by chitosan. The desorption of uranium from the sorbent allows the valorization of uranium and the re-use of the sorbent. (authors). 21 refs., 10 figs

  5. Flame Spectrophotometric Determination of Strontium in Water and Biological Material

    Energy Technology Data Exchange (ETDEWEB)

    Joensson, G

    1964-10-15

    A flame spectrophotometric method has been developed for the determination of strontium in biological material and water samples. Strontium is determined in the presence of calcium at a wavelength of 4607 A. The intensity of the strontium emission from the sample is increased if n-butanol is added to a solution of the sample in water. With a 6 vol% solution of n-butanol in water, an optimum intensity of 3.5 times that obtained with pure water solution is obtained. Anions and alkali metals which might interfere with the flame spectrophotometric determination are separated from the sample by a simple ion exchange operation. The method allows determination of strontium in solutions down to 0.1{mu}g/ml. In this case the standard deviation is 3.1 % and with a strontium concentration of 1 {mu}g/ml the deviation is 0.9 %. This method has been used for the determination of strontium in samples of varying composition such as bone, meat and skin from fishes, samples of human bones, shell-fish, milk, and water, in which case Sr quantities of 5{mu}g were determined with an analytical error of less than 5 % and Sr{sub q}uantities greater than 10 {mu}g with an error of less than 3 %.

  6. Flame Spectrophotometric Determination of Strontium in Water and Biological Material

    International Nuclear Information System (INIS)

    Joensson, G.

    1964-10-01

    A flame spectrophotometric method has been developed for the determination of strontium in biological material and water samples. Strontium is determined in the presence of calcium at a wavelength of 4607 A. The intensity of the strontium emission from the sample is increased if n-butanol is added to a solution of the sample in water. With a 6 vol% solution of n-butanol in water, an optimum intensity of 3.5 times that obtained with pure water solution is obtained. Anions and alkali metals which might interfere with the flame spectrophotometric determination are separated from the sample by a simple ion exchange operation. The method allows determination of strontium in solutions down to 0.1μg/ml. In this case the standard deviation is 3.1 % and with a strontium concentration of 1 μg/ml the deviation is 0.9 %. This method has been used for the determination of strontium in samples of varying composition such as bone, meat and skin from fishes, samples of human bones, shell-fish, milk, and water, in which case Sr quantities of 5μg were determined with an analytical error of less than 5 % and Sr q uantities greater than 10 μg with an error of less than 3 %

  7. Giant and universal magnetoelectric coupling in soft materials and concomitant ramifications for materials science and biology

    Science.gov (United States)

    Liu, Liping; Sharma, Pradeep

    2013-10-01

    Magnetoelectric coupling—the ability of a material to magnetize upon application of an electric field and, conversely, to polarize under the action of a magnetic field—is rare and restricted to a rather small set of exotic hard crystalline materials. Intense research activity has recently ensued on materials development, fundamental scientific issues, and applications related to this phenomenon. This tantalizing property, if present in adequate strength at room temperature, can be used to pave the way for next-generation memory devices such as miniature magnetic random access memories and multiple state memory bits, sensors, energy harvesting, spintronics, among others. In this Rapid Communication, we prove the existence of an overlooked strain mediated nonlinear mechanism that can be used to universally induce the giant magnetoelectric effect in all (sufficiently) soft dielectric materials. For soft polymer foams—which, for instance, may be used in stretchable electronics—we predict room-temperature magnetoelectric coefficients that are comparable to the best known (hard) composite materials created. We also argue, based on a simple quantitative model, that magnetoreception in some biological contexts (e.g., birds) most likely utilizes this very mechanism.

  8. Ceramic materials on perovskite-type structure for electronic applications

    International Nuclear Information System (INIS)

    Surowiak, Z.

    2003-01-01

    Ceramic materials exhibiting the perovskite-type structure constitute among others, resource base for many fields of widely understood electronics (i.e., piezoelectronics, accustoelectronics, optoelectronics, computer science, tele- and radioelectronics etc.). Most often they are used for fabrication of different type sensors (detectors), transducers, ferroelectric memories, limiters of the electronic current intensity, etc., and hence they are numbered among so-called intelligent materials. Prototype structure of this group of materials is the structure of the mineral called perovskite (CaTiO 3 ). By means of right choice of the chemical composition of ABO 3 and deforming the regular perovskite structure (m3m) more than 5000 different chemical compounds and solid solutions exhibiting the perovskite-type structure have been fabricated. The concept of perovskite functional ceramics among often things ferroelectric ceramics, pyroelectric ceramics, piezoelectric ceramics, electrostrictive ceramics, posistor ceramics, superconductive ceramics and ferromagnetic ceramics. New possibilities of application of the perovskite-type ceramics are opened by nanotechnology. (author)

  9. Low-energy electron inelastic mean free path in materials

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen-Truong, Hieu T., E-mail: nguyentruongthanhhieu@tdt.edu.vn [Theoretical Physics Research Group & Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City 756636 (Viet Nam)

    2016-04-25

    We show that the dielectric approach can determine electron inelastic mean free paths in materials with an accuracy equivalent to those from first-principle calculations in the GW approximation of many-body theory. The present approach is an alternative for calculating the hot-electron lifetime, which is an important quantity in ultrafast electron dynamics. This approach, applied here to solid copper for electron energies below 100 eV, yields results in agreement with experimental data from time-resolved two-photon photoemission, angle-resolved photoelectron spectroscopy, and X-ray absorption fine structure measurements in the energy ranges 2–3.5, 10–15, and 60–100 eV, respectively.

  10. "Rinse and trickle": a protocol for TEM preparation and investigation of inorganic fibers from biological material.

    Science.gov (United States)

    Vigliaturo, Ruggero; Capella, Silvana; Rinaudo, Caterina; Belluso, Elena

    2016-07-01

    The purpose of this work is to define a sample preparation protocol that allows inorganic fibers and particulate matter extracted from different biological samples to be characterized morphologically, crystallographically and chemically by transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS). The method does not damage or create artifacts through chemical attacks of the target material. A fairly rapid specimen preparation is applied with the aim of performing as few steps as possible to transfer the withdrawn inorganic matter onto the TEM grid. The biological sample is previously digested chemically by NaClO. The salt is then removed through a series of centrifugation and rinse cycles in deionized water, thus drastically reducing the digestive power of the NaClO and concentrating the fibers for TEM analysis. The concept of equivalent hydrodynamic diameter is introduced to calculate the settling velocity during the centrifugation cycles. This technique is applicable to lung tissues and can be extended to a wide range of organic materials. The procedure does not appear to cause morphological damage to the fibers or modify their chemistry or degree of crystallinity. The extrapolated data can be used in interdisciplinary studies to understand the pathological effects caused by inorganic materials.

  11. Materials and processing approaches for foundry-compatible transient electronics

    Science.gov (United States)

    Chang, Jan-Kai; Fang, Hui; Bower, Christopher A.; Song, Enming; Yu, Xinge; Rogers, John A.

    2017-07-01

    Foundry-based routes to transient silicon electronic devices have the potential to serve as the manufacturing basis for “green” electronic devices, biodegradable implants, hardware secure data storage systems, and unrecoverable remote devices. This article introduces materials and processing approaches that enable state-of-the-art silicon complementary metal-oxide-semiconductor (CMOS) foundries to be leveraged for high-performance, water-soluble forms of electronics. The key elements are (i) collections of biodegradable electronic materials (e.g., silicon, tungsten, silicon nitride, silicon dioxide) and device architectures that are compatible with manufacturing procedures currently used in the integrated circuit industry, (ii) release schemes and transfer printing methods for integration of multiple ultrathin components formed in this way onto biodegradable polymer substrates, and (iii) planarization and metallization techniques to yield interconnected and fully functional systems. Various CMOS devices and circuit elements created in this fashion and detailed measurements of their electrical characteristics highlight the capabilities. Accelerated dissolution studies in aqueous environments reveal the chemical kinetics associated with the underlying transient behaviors. The results demonstrate the technical feasibility for using foundry-based routes to sophisticated forms of transient electronic devices, with functional capabilities and cost structures that could support diverse applications in the biomedical, military, industrial, and consumer industries.

  12. The Chemical Modeling of Electronic Materials and Interconnections

    Science.gov (United States)

    Kivilahti, J. K.

    2002-12-01

    Thermodynamic and kinetic modeling, together with careful experimental work, is of great help for developing new electronic materials such as lead-free solders, their compatible metallizations and diffusion-barrier layers, as well as joining and bonding processes for advanced electronics manufacturing. When combined, these modeling techniques lead to a rationalization of the trial-and-error methods employed in the electronics industry, limiting experimentation and, thus, reducing significantly time-to-market of new products. This modeling provides useful information on the stabilities of phases (microstructures), driving forces for chemical reactions, and growth rates of reaction products occurring in interconnections or thin-film structures during processing, testing, and in longterm use of electronic devices. This is especially important when manufacturing advanced lead-free electronics where solder joint volumes are decreasing while the number of dissimilar reactive materials is increasing markedly. Therefore, a new concept of local nominal composition was introduced and applied together with the relevant ternary and multicomponent phase diagrams to some solder/conductor systems.

  13. Secondary electron interactions in materials with environmental and radiological interest

    International Nuclear Information System (INIS)

    Garcia, G.; Blanco, F.; Pablos, J.L. de; Perez, J.M.; Williart, A.

    2003-01-01

    Important environmental and radiological applications require energy deposition models including the interactions between secondary electrons and the atoms or molecules of the medium. In this work we propose a method to obtain reliable cross-section data to be used in these models by combining total and ionization cross-section measurements with simple calculations of the differential and integral elastic cross-sections. The energy loss spectra obtained in this experiment have been also used to drive stopping power of the considered materials for electrons. Some examples of results for atomic (Xe) and molecular (CF 4 ) targets are presented and discussed in this paper. (author)

  14. The 2016 oxide electronic materials and oxide interfaces roadmap

    DEFF Research Database (Denmark)

    Lorenz, M.; Rao, M. S. Ramachandra; Venkatesan, T.

    2016-01-01

    of these materials to understand the tunability of their properties and the novel properties that evolve due to their nanostructured nature is another facet of the challenge. The research related to the oxide electronic field is at an impressionable stage, and this has motivated us to contribute with a roadmap......, Pentcheva, and Gegenwart. Finally, Miletto Granozio presents the European action ‘towards oxide-based electronics’ which develops an oxide electronics roadmap with emphasis on future nonvolatile memories and the required technologies.In summary, we do hope that this oxide roadmap appears as an interesting...

  15. Spiers memorial lecture. Organic electronics: an organic materials perspective.

    Science.gov (United States)

    Wudl, Fred

    2014-01-01

    This Introductory Lecture is intended to provide a background to Faraday Discussion 174: "Organic Photonics and Electronics" and will consist of a chronological, subjective review of organic electronics. Starting with "ancient history" (1888) and history (1950-present), the article will take us to the present. The principal developments involved the processes of charge carrier generation and charge transport in molecular solids, starting with insulators (photoconductors) and moving to metals, to semiconductors and ending with the most popular semiconductor devices, such as organic light-emitting diodes (OLEDs), organic field effect transistors (OFETs) and organic photovoltaics (OPVs). The presentation will be from an organic chemistry/materials point of view.

  16. Organization and diffusion in biological and material fabrication problems

    Science.gov (United States)

    Mangan, Niall Mari

    This thesis is composed of two problems. The first is a systems level analysis of the carbon concentrating mechanism in cyanobacteria. The second presents a theoretical analysis of femtosecond laser melting for the purpose of hyperdoping silicon with sulfur. While these systems are very distant, they are both relevant to the development of alternative energy (production of biofuels and methods for fabricating photovoltaics respectively). Both problems are approached through analysis of the underlying diffusion equations. Cyanobacteria are photosynthetic bacteria with a unique carbon concentrating mechanism (CCM) which enhances carbon fixation. A greater understanding of this mechanism would offer new insights into the basic biology and methods for bioengineering more efficient biochemical reactions. The molecular components of the CCM have been well characterized in the last decade, with genetic analysis uncovering both variation and commonalities in CCMs across cyanobacteria strains. Analysis of CCMs on a systems level, however, is based on models formulated prior to the molecular characterization. We present an updated model of the cyanobacteria CCM, and analytic solutions in terms of the various molecular components. The solutions allow us to find the parameter regime (expression levels, catalytic rates, permeability of carboxysome shell) where carbon fixation is maximized and oxygenation is minimized. Saturation of RuBisCO, maximization of the ratio of CO2 to O2, and staying below or at the saturation level for carbonic anhydrase are all needed for maximum efficacy. These constraints limit the parameter regime where the most effective carbon fixation can occur. There is an optimal non-specific carboxysome shell permeability, where trapping of CO2 is maximized, but HCO3 - is not detrimentally restricted. The shell also shields carbonic anhydrase activity and CO2 → HCO3- conversion at the thylakoid and cell membrane from one another. Co-localization of carbonic

  17. Atomic-resolution transmission electron microscopy of electron beam–sensitive crystalline materials

    Science.gov (United States)

    Zhang, Daliang; Zhu, Yihan; Liu, Lingmei; Ying, Xiangrong; Hsiung, Chia-En; Sougrat, Rachid; Li, Kun; Han, Yu

    2018-02-01

    High-resolution imaging of electron beam–sensitive materials is one of the most difficult applications of transmission electron microscopy (TEM). The challenges are manifold, including the acquisition of images with extremely low beam doses, the time-constrained search for crystal zone axes, the precise image alignment, and the accurate determination of the defocus value. We develop a suite of methods to fulfill these requirements and acquire atomic-resolution TEM images of several metal organic frameworks that are generally recognized as highly sensitive to electron beams. The high image resolution allows us to identify individual metal atomic columns, various types of surface termination, and benzene rings in the organic linkers. We also apply our methods to other electron beam–sensitive materials, including the organic-inorganic hybrid perovskite CH3NH3PbBr3.

  18. Atomic-resolution transmission electron microscopy of electron beam–sensitive crystalline materials

    KAUST Repository

    Zhang, Daliang

    2018-01-18

    High-resolution imaging of electron beam-sensitive materials is one of the most difficult applications of transmission electron microscopy (TEM). The challenges are manifold, including the acquisition of images with extremely low beam doses, the time-constrained search for crystal zone axes, the precise image alignment, and the accurate determination of the defocus value. We develop a suite of methods to fulfill these requirements and acquire atomic-resolution TEM images of several metal organic frameworks that are generally recognized as highly sensitive to electron beams. The high image resolution allows us to identify individual metal atomic columns, various types of surface termination, and benzene rings in the organic linkers. We also apply our methods to other electron beam–sensitive materials, including the organic-inorganic hybrid perovskite CH3NH3PbBr3.

  19. The use of an ion-beam source to alter the surface morphology of biological implant materials

    Science.gov (United States)

    Weigand, A. J.

    1978-01-01

    An electron-bombardment ion-thruster was used as a neutralized-ion-beam sputtering source to texture the surfaces of biological implant materials. The materials investigated included 316 stainless steel; titanium-6% aluminum, 4% vanadium; cobalt-20% chromium, 15% tungsten; cobalt-35% nickel, 20% chromium, 10% molybdenum; polytetrafluoroethylene; polyoxymethylene; silicone and polyurethane copolymer; 32%-carbon-impregnated polyolefin; segmented polyurethane; silicone rubber; and alumina. Scanning electron microscopy was used to determine surface morphology changes of all materials after ion-texturing. Electron spectroscopy for chemical analysis was used to determine the effects of ion-texturing on the surface chemical composition of some polymers. Liquid contact angle data were obtained for ion-textured and untextured polymer samples. Results of tensile and fatigue tests of ion-textured metal alloys are presented. Preliminary data of tissue response to ion-textured surfaces of some metals, polytetrafluoroethylene, alumina, and segmented polyurethane have been obtained.

  20. Soft Active Materials for Actuation, Sensing, and Electronics

    Science.gov (United States)

    Kramer, Rebecca Krone

    Future generations of robots, electronics, and assistive medical devices will include systems that are soft and elastically deformable, allowing them to adapt their morphology in unstructured environments. This will require soft active materials for actuation, circuitry, and sensing of deformation and contact pressure. The emerging field of soft robotics utilizes these soft active materials to mimic the inherent compliance of natural soft-bodied systems. As the elasticity of robot components increases, the challenges for functionality revert to basic questions of fabrication, materials, and design - whereas such aspects are far more developed for traditional rigid-bodied systems. This thesis will highlight preliminary materials and designs that address the need for soft actuators and sensors, as well as emerging fabrication techniques for manufacturing stretchable circuits and devices based on liquid-embedded elastomers.

  1. Synthesis Properties and Electron Spin Resonance Properties of Titanic Materials

    International Nuclear Information System (INIS)

    Cho, Jung Min; Lee, Jun; Kim, Tak Hee; Sun, Min Ho; Jang, Young Bae; Cho, Sung June

    2009-01-01

    Titanic materials were synthesized by hydrothermal method of TiO 2 anatase in 10M LiOH, 10M NaOH, and 14M KOH at 130 deg. C for 30 hours. Alkaline media were removed from the synthesized products using 0.1N HCl aqueous solution. The as-prepared samples were characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction, Brunauer-Emmett-Teller isotherm, and electron spin resonance. Different shapes of synthesized products were observed through the typical electron microscope and indicated that the formation of the different morphologies depends on the treatment conditions of highly alkaline media. Many micropores were observed in the cubic or octahedral type of TiO 2 samples through the typical electron microscope and Langmuir adsorption-desorption isotherm of liquid nitrogen at 77 deg. K. Electron spin resonance studies have also been carried out to verify the existence of paramagnetic sites such as oxygen vacancies on the titania samples. The effect of alkali metal ions on the morphologies and physicochemical properties of nanoscale titania are discussed.

  2. High-resolution electron microscopy of advanced materials

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, T.E.; Kung, H.H.; Sickafus, K.E.; Gray, G.T. III; Field, R.D.; Smith, J.F. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.

    1997-11-01

    This final report chronicles a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The High-Resolution Electron Microscopy Facility has doubled in size and tripled in quality since the beginning of the three-year period. The facility now includes a field-emission scanning electron microscope, a 100 kV field-emission scanning transmission electron microscope (FE-STEM), a 300 kV field-emission high-resolution transmission electron microscope (FE-HRTEM), and a 300 kV analytical transmission electron microscope. A new orientation imaging microscope is being installed. X-ray energy dispersive spectrometers for chemical analysis are available on all four microscopes; parallel electron energy loss spectrometers are operational on the FE-STEM and FE-HRTEM. These systems enable evaluation of local atomic bonding, as well as chemical composition in nanometer-scale regions. The FE-HRTEM has a point-to-point resolution of 1.6 {angstrom}, but the resolution can be pushed to its information limit of 1 {angstrom} by computer reconstruction of a focal series of images. HRTEM has been used to image the atomic structure of defects such as dislocations, grain boundaries, and interfaces in a variety of materials from superconductors and ferroelectrics to structural ceramics and intermetallics.

  3. Deciphering the language between biological and synthetic materials

    Directory of Open Access Journals (Sweden)

    Paolo A. Netti

    2014-06-01

    Full Text Available Chemical signals propagating through aqueous environment are at the basis of the language utilized by living systems to exchange information. In the last years, molecular biology has partly disclosed the grammar and the syntax of this complex language revealing the fascinating world of molecular communication that is the foundation of biological development.

  4. Use of analytical electron microscopy and auger electron spectroscopy for evaluating materials

    International Nuclear Information System (INIS)

    Jones, R.H.; Bruemmer, S.M.; Thomas, M.T.; Baer, D.R.

    1982-11-01

    Analytical electron microscopy (AEM) can be used to characterize the microstructure and microchemistry of materials over dimensions less than 10 nm while Auger electron spectroscopy (AES) can be used to characterize the chemical composition of surfaces and interfaces to a depth of less than 1 nm. Frequently, the information gained from both instruments can be coupled to give new insight into the behavior of materials. Examples of the use of AEM and AES to characterize segregation, sensitization and radiation damage are presented. A short description of the AEM and AES techniques are given

  5. Attosecond Electron Processes in Materials: Excitons, Plasmons, and Charge Dynamics

    Science.gov (United States)

    2015-05-19

    focused using a f=1.5 m lens into a 250 micron hollow core fiber (HCF) filled with neon gas at atmospheric pressure to stretch the pulse spectrum from... insulator to metal transition. Introduction: The goal of this work was to understand the generation, transport, and manipulation of electronic charge...chemically sensitive probe pulse utilizing specific core level transitions in atoms that are part of a material under study. The measurements follow

  6. Nanocellulose as Material Building Block for Energy and Flexible Electronics

    Science.gov (United States)

    Hu, Liangbing

    2014-03-01

    In this talk, I will discuss the fabrications, properties and device applications of functional nanostructured paper based on nanocellulose. Nanostructures with tunable optical, electrical, ionic and mechanical properties will be discussed. Lab-scale demonstration devices, including low-cost Na-ion batteries, microbial fuel cells, solar cells, transparent transistors, actuators and touch screens will be briefly mentioned. These studies show that nanocellulose is a promising green material for electronics and energy devices.

  7. Electron Acceptor Materials Engineering in Colloidal Quantum Dot Solar Cells

    KAUST Repository

    Liu, Huan

    2011-07-15

    Lead sulfide colloidal quantum dot (CQD) solar cells with a solar power conversion efficiency of 5.6% are reported. The result is achieved through careful optimization of the titanium dioxide electrode that serves as the electron acceptor. Metal-ion-doped sol-gel-derived titanium dioxide electrodes produce a tunable-bandedge, well-passivated materials platform for CQD solar cell optimization. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Radiation effects on and dose enhancement of electronic materials

    International Nuclear Information System (INIS)

    Srour, J.R.; Long, D.M.

    1984-01-01

    This book describes radiation effects on and dose enhancement factors for electronic materials. Alteration of the electrical properties of solid-state devices and integrated circuits by impinging radiation is well-known. Such changes may cause an electronic subsystem to fail, thus there is currently great interest in devising methods for avoiding radiation-induced degradation. The development of radiation-hardened devices and circuits is an exciting approach to solving this problem for many applications, since it could minimize the need for shielding or other system hardening techniques. Part 1 describes the basic mechanisms of radiation effects on electronic materials, devices, and integrated circuits. Radiation effects in bulk silicon and in silicon devices are treated. Ionizing radiation effects in silicon dioxide films and silicon MOS devices are discussed. Single event phenomena are considered. Key literature references and a bibliography are provided. Part II provides tabulations of dose enhancement factors for electronic devices in x-ray and gamma-ray environments. The data are applicable to a wide range of semiconductor devices and selected types of capacitors. Radiation environments discussed find application in system design and in radiation test facilities

  9. Three-Dimensional scanning transmission electron microscopy of biological specimens

    KAUST Repository

    De Jonge, Niels; Sougrat, Rachid; Northan, Brian M.; Pennycook, Stephen J.

    2010-01-01

    A three-dimensional (3D) reconstruction of the cytoskeleton and a clathrin-coated pit in mammalian cells has been achieved from a focal-series of images recorded in an aberration-corrected scanning transmission electron microscope (STEM

  10. Investigation of thermal management materials for automotive electronic control units

    International Nuclear Information System (INIS)

    Mallik, Sabuj; Ekere, Ndy; Best, Chris; Bhatti, Raj

    2011-01-01

    Today's electronics packages are smaller and more powerful than ever before. This leads to ever increasing thermal challenges for the systems designer. The automotive electronic control unit (ECU) package faces the same challenge of thermal management as the industry in general. This is coupled with the latest European Union legislation (Euro 6 standard) which forced the ECU manufacturers to completely re-design their ECU platform with improved hardware and software capability. This will result in increased power densities and therefore, the ability to dissipate heat will be a key factor. A higher thermal conductivity (TC) material for the ECU housing (than the currently used Aluminium) could improve heat dissipation from the ECU. This paper critically reviews the state-of-the-art in thermal management materials which may be applicable to an automotive ECU. This review shows that of the different materials currently available, the Al/SiC composites in particular have very good potential for automotive ECU application. In terms of metal composites processing, the liquid metal infiltration process is recommended as it has a lower processing cost and it also has the ability to produce near net-shape materials.

  11. Transmission electron microscopy a textbook for materials science

    CERN Document Server

    Williams, David B

    1996-01-01

    Electron microscopy has revolutionized our understanding the extraordinary intellectual demands required of the mi­ of materials by completing the processing-structure-prop­ croscopist in order to do the job properly: crystallography, erties links down to atomistic levels. It now is even possible diffraction, image contrast, inelastic scattering events, and to tailor the microstructure (and meso structure ) of materials spectroscopy. Remember, these used to be fields in them­ to achieve specific sets of properties; the extraordinary abili­ selves. Today, one has to understand the fundamentals ties of modem transmission electron microscopy-TEM­ of all of these areas before one can hope to tackle signifi­ instruments to provide almost all of the structural, phase, cant problems in materials science. TEM is a technique of and crystallographic data allow us to accomplish this feat. characterizing materials down to the atomic limits. It must Therefore, it is obvious that any curriculum in modem mate­ be use...

  12. Imaging of soft and hard materials using a Boersch phase plate in a transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Alloyeau, D., E-mail: alloyeau.damien@gmail.com [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS/72, Berkeley, CA 94720 (United States); Hsieh, W.K. [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS/72, Berkeley, CA 94720 (United States); Anderson, E.H.; Hilken, L. [Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley CA 94720 (United States); Benner, G. [Carl Zeiss NTS GmbH, Oberkochen 73447 (Germany); Meng, X. [Electrical Engineering and Computer Sciences, UC Berkeley, Berkeley, CA 94720-1770 (United States); Chen, F.R. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan (China); Kisielowski, C. [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS/72, Berkeley, CA 94720 (United States)

    2010-04-15

    Using two levels of electron beam lithography, vapor phase deposition techniques, and FIB etching, we have fabricated an electrostatic Boersch phase plate for contrast enhancement of weak phase objects in a transmission electron microscope. The phase plate has suitable dimensions for the imaging of small biological samples without compromising the high-resolution capabilities of the microscope. A micro-structured electrode allows for phase tuning of the unscattered electron beam, which enables the recording of contrast enhanced in-focus images and in-line holograms. We have demonstrated experimentally that our phase plate improves the contrast of carbon nanotubes while maintaining high-resolution imaging performance, which is demonstrated for the case of an AlGaAs heterostructure. The development opens a new way to study interfaces between soft and hard materials.

  13. Hybrid materials engineering in biology, chemistry and physics

    NARCIS (Netherlands)

    Leroux, F; Rabu, P; Sommerdijk, N.A.J.M.; Taubert, A.

    The Guest Editors emphasize the rapidly growing research in advanced materials. "Telecommunication, health and environment, energy and transportation, and sustainability are just a few examples where new materials have been key for technological advancement."

  14. Fundamental Technical Elements of Freeze-fracture/Freeze-etch in Biological Electron Microscopy

    Science.gov (United States)

    Freeze-fracture/freeze-etch describes a process whereby specimens, typically biological or nanomaterial in nature, are frozen, fractured, and replicated to generate a carbon/platinum "cast" intended for examination by transmission electron microscopy. Specimens are subjected to u...

  15. Application of scandium oxide in an electron emission material

    International Nuclear Information System (INIS)

    Suqiu, Y.; Zhizheng, Z.; Yongde, W.

    1985-01-01

    Modern microwave devices impose a number of harsh requirements on the cathodes. For instance, they require cathodes having low working temperature, high emissive current density, slow evaporation rate of the emissive-active material, long lifetime, quick heating and so on. The commercial B-cathode is no longer able to meet these requirements completely. A scandate cathode may be a promising one for use in these devices. Adding rare-earth elements in the electron emission material has been reported in many papers. Based on a B-cathode we add a little amount of scandium oxide (about 3%) into emission material to manufacture a scandate cathode. The emission property of such a cathode has been improved greatly. If the composition is controlled correctly, the emission level of such a cathode may be five times more as high as the B-cathode

  16. Development of nanocomposite polymer materials for electrical and electronic applications

    International Nuclear Information System (INIS)

    Chine, Bruno

    2007-01-01

    Some results and experimental procedures of laboratory are reported in the frame of researches conducted for the development of new nanostructured composite materials. These new materials, which are constituted by an organic phase: the polymer and an inorganic phase: the silicate, are being strongly investigated nowadays so it is expected that they could provide, among other, better electrical insulation properties and flame-delay in electrical and electronic applications. The laboratory experimental work has been developed from two families of polymers, thermoplastics and thermosets and clays silicates providing lamellar type. There are now some preliminary results, such as obtaining thin films of these nanocomposite materials, their complete characterization by X-ray diffraction, scanning microscopy and thermogravimetric analysis, they do well to wait for future research activities. (author) [es

  17. Spatiotemporal Observation of Electron-Impact Dynamics in Photovoltaic Materials Using 4D Electron Microscopy

    KAUST Repository

    Shaheen, Basamat

    2017-05-17

    Understanding light-triggered charge carrier dynamics near photovoltaic-material surfaces and at interfaces has been a key element and one of the major challenges for the development of real-world energy devices. Visualization of such dynamics information can be obtained using the one-of-a-kind methodology of scanning ultrafast electron microscopy (S-UEM). Here, we address the fundamental issue of how the thickness of the absorber layer may significantly affect the charge carrier dynamics on material surfaces. Time-resolved snapshots indicate that the dynamics of charge carriers generated by electron impact in the electron-photon dynamical probing regime is highly sensitive to the thickness of the absorber layer, as demonstrated using CdSe films of different thicknesses as a model system. This finding not only provides the foundation for potential applications of S-UEM to a wide range of devices in the fields of chemical and materials research, but also has impact on the use and interpretation of electron beam-induced current for optimization of photoactive materials in these devices.

  18. 3D imaging by serial block face scanning electron microscopy for materials science using ultramicrotomy.

    Science.gov (United States)

    Hashimoto, Teruo; Thompson, George E; Zhou, Xiaorong; Withers, Philip J

    2016-04-01

    Mechanical serial block face scanning electron microscopy (SBFSEM) has emerged as a means of obtaining three dimensional (3D) electron images over volumes much larger than possible by focused ion beam (FIB) serial sectioning and at higher spatial resolution than achievable with conventional X-ray computed tomography (CT). Such high resolution 3D electron images can be employed for precisely determining the shape, volume fraction, distribution and connectivity of important microstructural features. While soft (fixed or frozen) biological samples are particularly well suited for nanoscale sectioning using an ultramicrotome, the technique can also produce excellent 3D images at electron microscope resolution in a time and resource-efficient manner for engineering materials. Currently, a lack of appreciation of the capabilities of ultramicrotomy and the operational challenges associated with minimising artefacts for different materials is limiting its wider application to engineering materials. Consequently, this paper outlines the current state of the art for SBFSEM examining in detail how damage is introduced during slicing and highlighting strategies for minimising such damage. A particular focus of the study is the acquisition of 3D images for a variety of metallic and coated systems. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  19. Flexible organic electronic devices: Materials, process and applications

    International Nuclear Information System (INIS)

    Logothetidis, Stergios

    2008-01-01

    The research for the development of flexible organic electronic devices (FEDs) is rapidly increasing worldwide, since FEDs will change radically several aspects of everyday life. Although there has been considerable progress in the area of flexible inorganic devices (a-Si or solution processed Si), there are numerous advances in the organic (semiconducting, conducting and insulating), inorganic and hybrid (organic-inorganic) materials that exhibit customized properties and stability, and in the synthesis and preparation methods, which are characterized by a significant amount of multidisciplinary efforts. Furthermore, the development and encapsulation of organic electronic devices onto flexible polymeric substrates by large-scale and low-cost roll-to-roll production processes will allow their market implementation in numerous application areas, including displays, lighting, photovoltaics, radio-frequency identification circuitry and chemical sensors, as well as to a new generation of modern exotic applications. In this work, we report on some of the latest advances in the fields of polymeric substrates, hybrid barrier layers, inorganic and organic materials to be used as novel active and functional thin films and nanomaterials as well as for the encapsulation of the materials components for the production of FEDs (flexible organic light-emitting diodes, and organic photovoltaics). Moreover, we will emphasize on the real-time optical monitoring and characterization of the growing films onto the flexible polymeric substrates by spectroscopic ellipsometry methods. Finally, the potentiality for the in-line characterization processes for the development of organic electronics materials will be emphasized, since it will also establish the framework for the achievement of the future scientific and technological breakthroughs

  20. Design of materials configurations for enhanced phononic and electronic properties

    Science.gov (United States)

    Daraio, Chiara

    The discovery of novel nonlinear dynamic and electronic phenomena is presented for the specific cases of granular materials and carbon nanotubes. This research was conducted for designing and constructing optimized macro-, micro- and nano-scale structural configurations of materials, and for studying their phononic and electronic behavior. Variation of composite arrangements of granular elements with different elastic properties in a linear chain-of-sphere, Y-junction or 3-D configurations led to a variety of novel phononic phenomena and interesting physical properties, which can be potentially useful for security, communications, mechanical and biomedical engineering applications. Mechanical and electronic properties of carbon nanotubes with different atomic arrangements and microstructures were also investigated. Electronic properties of Y-junction configured carbon nanotubes exhibit an exciting transistor switch behavior which is not seen in linear configuration nanotubes. Strongly nonlinear materials were designed and fabricated using novel and innovative concepts. Due to their unique strongly nonlinear and anisotropic nature, novel wave phenomena have been discovered. Specifically, violations of Snell's law were detected and a new mechanism of wave interaction with interfaces between NTPCs (Nonlinear Tunable Phononic Crystals) was established. Polymer-based systems were tested for the first time, and the tunability of the solitary waves speed was demonstrated. New materials with transformed signal propagation speed in the manageable range of 10-100 m/s and signal amplitude typical for audible speech have been developed. The enhancing of the mitigation of solitary and shock waves in 1-D chains were demonstrated and a new protective medium was designed for practical applications. 1-D, 2-D and 3-D strongly nonlinear system have been investigated providing a broad impact on the whole area of strongly nonlinear wave dynamics and creating experimental basis for new

  1. Methanol as electron donor for thermophilic biological sulfate and sulfite reduction

    NARCIS (Netherlands)

    Weijma, J.

    2000-01-01

    Sulfur oxyanions (e.g. sulfate, sulfite) can be removed from aqueous waste- and process streams by biological reduction with a suitable electron donor to sulfide, followed by partial chemical or biological oxidation of sulfide to elemental sulfur. The aim of the research described in this

  2. Electronic materials with a wide band gap: recent developments

    Directory of Open Access Journals (Sweden)

    Detlef Klimm

    2014-09-01

    Full Text Available The development of semiconductor electronics is reviewed briefly, beginning with the development of germanium devices (band gap Eg = 0.66 eV after World War II. A tendency towards alternative materials with wider band gaps quickly became apparent, starting with silicon (Eg = 1.12 eV. This improved the signal-to-noise ratio for classical electronic applications. Both semiconductors have a tetrahedral coordination, and by isoelectronic alternative replacement of Ge or Si with carbon or various anions and cations, other semiconductors with wider Eg were obtained. These are transparent to visible light and belong to the group of wide band gap semiconductors. Nowadays, some nitrides, especially GaN and AlN, are the most important materials for optical emission in the ultraviolet and blue regions. Oxide crystals, such as ZnO and β-Ga2O3, offer similarly good electronic properties but still suffer from significant difficulties in obtaining stable and technologically adequate p-type conductivity.

  3. Electron tomography of porous materials and magnetic nanoparticles

    International Nuclear Information System (INIS)

    Uusimäki, T.

    2015-01-01

    Electron tomography, as carried out in a transmission electron microscope is a method to reveal the three dimensional structure of the sample at the nanometer scale. It is based on tilting the sample and recording subsequent images at different projections angles. Using specific reconstruction algorithms the density distribution of the sample can then be reproduced. In this thesis, electron tomography has been implemented for material science specimens and more rigorously to porous media infiltrated with magnetic nanoparticles. The volume and spatial distribution along with the knowledge of the demagnetizing factors were then used within a magnetic Monte Carlo simulation to predict the magnetic response of the nanoparticle assembly. The local curvature of nanoparticles within the template, known to be a critical geometrical parameter influencing material properties, was extracted with two distinctive methods. Furthermore, new capabilities needed for image analysis and processing of the tilt series had to be implemented for improved alignments and segmentation. A new method to align the tilt series without depending on markers was written for obtaining high quality reconstructions. Also a comparison was made between different scanning TEM acquisition modes such as incoherent bright field and high angle annular dark field imaging modes with respect to resolution and contrast changes. (author) [de

  4. Flexible diodes for radio frequency (RF) electronics: a materials perspective

    KAUST Repository

    Semple, James

    2017-10-30

    Over the last decade, there has been increasing interest in transferring the research advances in radiofrequency (RF) rectifiers, the quintessential element of the chip in the RF identification (RFID) tags, obtained on rigid substrates onto plastic (flexible) substrates. The growing demand for flexible RFID tags, wireless communications applications and wireless energy harvesting systems that can be produced at a low-cost is a key driver for this technology push. In this topical review, we summarise recent progress and status of flexible RF diodes and rectifying circuits, with specific focus on materials and device processing aspects. To this end, different families of materials (e.g. flexible silicon, metal oxides, organic and carbon nanomaterials), manufacturing processes (e.g. vacuum and solution processing) and device architectures (diodes and transistors) are compared. Although emphasis is placed on performance, functionality, mechanical flexibility and operating stability, the various bottlenecks associated with each technology are also addressed. Finally, we present our outlook on the commercialisation potential and on the positioning of each material class in the RF electronics landscape based on the findings summarised herein. It is beyond doubt that the field of flexible high and ultra-high frequency rectifiers and electronics as a whole will continue to be an active area of research over the coming years.

  5. Flexible diodes for radio frequency (RF) electronics: a materials perspective

    KAUST Repository

    Semple, James; Georgiadou, Dimitra G; Wyatt-Moon, Gwenhivir; Gelinck, Gerwin; Anthopoulos, Thomas D.

    2017-01-01

    Over the last decade, there has been increasing interest in transferring the research advances in radiofrequency (RF) rectifiers, the quintessential element of the chip in the RF identification (RFID) tags, obtained on rigid substrates onto plastic (flexible) substrates. The growing demand for flexible RFID tags, wireless communications applications and wireless energy harvesting systems that can be produced at a low-cost is a key driver for this technology push. In this topical review, we summarise recent progress and status of flexible RF diodes and rectifying circuits, with specific focus on materials and device processing aspects. To this end, different families of materials (e.g. flexible silicon, metal oxides, organic and carbon nanomaterials), manufacturing processes (e.g. vacuum and solution processing) and device architectures (diodes and transistors) are compared. Although emphasis is placed on performance, functionality, mechanical flexibility and operating stability, the various bottlenecks associated with each technology are also addressed. Finally, we present our outlook on the commercialisation potential and on the positioning of each material class in the RF electronics landscape based on the findings summarised herein. It is beyond doubt that the field of flexible high and ultra-high frequency rectifiers and electronics as a whole will continue to be an active area of research over the coming years.

  6. Virtual screening of electron acceptor materials for organic photovoltaic applications

    International Nuclear Information System (INIS)

    D Halls, Mathew; Giesen, David J; Goldberg, Alexander; Djurovich, Peter J; Sommer, Jonathan; McAnally, Eric; Thompson, Mark E

    2013-01-01

    Virtual screening involves the generation of structure libraries, automated analysis to predict properties related to application performance and subsequent screening to identify lead systems and estimate critical structure–property limits across a targeted chemical design space. This approach holds great promise for informing experimental discovery and development efforts for next-generation materials, such as organic semiconductors. In this work, the virtual screening approach is illustrated for nitrogen-substituted pentacene molecules to identify systems for development as electron acceptor materials for use in organic photovoltaic (OPV) devices. A structure library of tetra-azapentacenes (TAPs) was generated by substituting four nitrogens for CH at 12 sites on the pentacene molecular framework. Molecular properties (e.g. E LUMO , E g and μ) were computed for each candidate structure using hybrid DFT at the B3LYP/6-311G** level of theory. The resulting TAPs library was then analyzed with respect to intrinsic properties associated with OPV acceptor performance. Marcus reorganization energies for charge transport for the most favorable TAP candidates were then calculated to further determine suitability as OPV electron acceptors. The synthesis, characterization and OPV device testing of TAP materials is underway, guided by these results. (paper)

  7. Flexible diodes for radio frequency (RF) electronics: a materials perspective

    Science.gov (United States)

    Semple, James; Georgiadou, Dimitra G.; Wyatt-Moon, Gwenhivir; Gelinck, Gerwin; Anthopoulos, Thomas D.

    2017-12-01

    Over the last decade, there has been increasing interest in transferring the research advances in radiofrequency (RF) rectifiers, the quintessential element of the chip in the RF identification (RFID) tags, obtained on rigid substrates onto plastic (flexible) substrates. The growing demand for flexible RFID tags, wireless communications applications and wireless energy harvesting systems that can be produced at a low-cost is a key driver for this technology push. In this topical review, we summarise recent progress and status of flexible RF diodes and rectifying circuits, with specific focus on materials and device processing aspects. To this end, different families of materials (e.g. flexible silicon, metal oxides, organic and carbon nanomaterials), manufacturing processes (e.g. vacuum and solution processing) and device architectures (diodes and transistors) are compared. Although emphasis is placed on performance, functionality, mechanical flexibility and operating stability, the various bottlenecks associated with each technology are also addressed. Finally, we present our outlook on the commercialisation potential and on the positioning of each material class in the RF electronics landscape based on the findings summarised herein. It is beyond doubt that the field of flexible high and ultra-high frequency rectifiers and electronics as a whole will continue to be an active area of research over the coming years.

  8. Multiscale modeling of emergent materials: biological and soft matter

    DEFF Research Database (Denmark)

    Murtola, Teemu; Bunker, Alex; Vattulainen, Ilpo

    2009-01-01

    In this review, we focus on four current related issues in multiscale modeling of soft and biological matter. First, we discuss how to use structural information from detailed models (or experiments) to construct coarse-grained ones in a hierarchical and systematic way. This is discussed in the c......In this review, we focus on four current related issues in multiscale modeling of soft and biological matter. First, we discuss how to use structural information from detailed models (or experiments) to construct coarse-grained ones in a hierarchical and systematic way. This is discussed...

  9. The Use of Liquid Isopropyl Alcohol and Hydrogen Peroxide Gas Plasma to Biologically Decontaminate Spacecraft Electronics

    Science.gov (United States)

    Bonner, J. K.; Tudryn, Carissa D.; Choi, Sun J.; Eulogio, Sebastian E.; Roberts, Timothy J.; Tudryn, Carissa D.

    2006-01-01

    Legitimate concern exists regarding sending spacecraft and their associated hardware to solar system bodies where they could possibly contaminate the body's surface with terrestrial microorganisms. The NASA approved guidelines for sterilization as set forth in NPG 8020.12C, which is consistent with the biological contamination control objectives of the Committee on Space Research (COSPAR), recommends subjecting the spacecraft and its associated hardware to dry heat-a dry heat regimen that could potentially employ a temperature of 110(deg)C for up to 200 hours. Such a temperature exposure could prove detrimental to the spacecraft electronics. The stimulated growth of intermetallic compounds (IMCs) in metallic interconnects and/or thermal degradation of organic materials composing much of the hardware could take place over a prolonged temperature regimen. Such detrimental phenomena would almost certainly compromise the integrity and reliability of the electronics. Investigation of sterilization procedures in the medical field suggests that hydrogen peroxide (H202) gas plasma (HPGP) technology can effectively function as an alternative to heat sterilization, especially for heat-sensitive items. Treatment with isopropyl alcohol (IPA) in liquid form prior to exposure of the hardware to HPGP should also prove beneficial. Although IPA is not a sterilant, it is frequently used as a disinfectant because of its bactericidal properties. The use of IPA in electronics cleaning is widely recognized and has been utilized for many years with no adverse affects reported. In addition, IPA is the principal ingredient of the test fluid used in ionic contamination testers to assess the amount of ionic contamination found on the surfaces of printed wiring assemblies. This paper will set forth experimental data confirming the feasibility of the IPA/H202 approach to reach acceptable microbial reduction (MR) levels of spacecraft electronic hardware. In addition, a proposed process flow in

  10. Strategy on biological evaluation for biodegradable/absorbable materials and medical devices.

    Science.gov (United States)

    Liu, Chenghu; Luo, Hongyu; Wan, Min; Hou, Li; Wang, Xin; Shi, Yanping

    2018-01-01

    During the last two decades, biodegradable/absorbable materials which have many benefits over conventional implants are being sought in clinical practices. However, to date, it still remains obscure for us to perform full physic-chemical characterization and biological risk assessment for these materials and related devices due to their complex design and coherent processing. In this review, based on the art of knowledge for biodegradable/absorbable materials and biological risk assessment, we demonstrated some promising strategies to establish and improve the current biological evaluation systems for these biodegradable/absorbable materials and related medical devices.

  11. Chitosan to Connect Biology to Electronics: Fabricating the Bio-Device Interface and Communicating Across This Interface

    Directory of Open Access Journals (Sweden)

    Eunkyoung Kim

    2014-12-01

    Full Text Available Individually, advances in microelectronics and biology transformed the way we live our lives. However, there remain few examples in which biology and electronics have been interfaced to create synergistic capabilities. We believe there are two major challenges to the integration of biological components into microelectronic systems: (i assembly of the biological components at an electrode address, and (ii communication between the assembled biological components and the underlying electrode. Chitosan possesses a unique combination of properties to meet these challenges and serve as an effective bio-device interface material. For assembly, chitosan’s pH-responsive film-forming properties allow it to “recognize” electrode-imposed signals and respond by self-assembling as a stable hydrogel film through a cathodic electrodeposition mechanism. A separate anodic electrodeposition mechanism was recently reported and this also allows chitosan hydrogel films to be assembled at an electrode address. Protein-based biofunctionality can be conferred to electrodeposited films through a variety of physical, chemical and biological methods. For communication, we are investigating redox-active catechol-modified chitosan films as an interface to bridge redox-based communication between biology and an electrode. Despite significant progress over the last decade, many questions still remain which warrants even deeper study of chitosan’s structure, properties, and functions.

  12. Electron microscopy of fine-grained extraterrestrial materials

    International Nuclear Information System (INIS)

    Mackinnon, I.D.R.; McKay, D.S.; Isaacs, A.M.; Nace, G.

    1982-01-01

    Electron micrographs are shown of (a) Mighei C2 carbonaceous chondrite (variety of matrix phases present; micro-diffraction patterns of a region showing small, discrete intergrowths of planar serpentine and an ordered mixed-layer material; figures showing examples of textures which may be interpreted in terms of alteration processes, and inclusions); and (b) a typical cosmic dust particle collected by high-flying aircraft in the Earth's stratosphere. The composition and morphology of the samples are discussed and their significance. (U.K.)

  13. Highlighting material structure with transmission electron diffraction correlation coefficient maps

    International Nuclear Information System (INIS)

    Kiss, Ákos K.; Rauch, Edgar F.; Lábár, János L.

    2016-01-01

    Correlation coefficient maps are constructed by computing the differences between neighboring diffraction patterns collected in a transmission electron microscope in scanning mode. The maps are shown to highlight material structural features like grain boundaries, second phase particles or dislocations. The inclination of the inner crystal interfaces are directly deduced from the resulting contrast. - Highlights: • We propose a novel technique to image the structure of polycrystalline TEM-samples. • Correlation coefficients maps highlights the evolution of the diffracting signal. • 3D views of grain boundaries are provided for nano-particles or polycrystals.

  14. Electron microscopy studies of materials used for hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Andrei, Carmen M.

    2004-07-01

    Concerns over global warming and air pollution have stimulated the concept of the ''Hydrogen Economy'' and the potential extensive use of hydrogen as an energy carrier. Hydrogen storage in a solid matrix has become one of the promising solutions for vehicular applications. In this study, several transmission electron microscopy (TEM) techniques such as high resolution (HR), electron diffraction, energy dispersive X-ray spectroscopy (EDS), electron energy loss spectroscopy (EELS) and energy-filtered transmission electron microscopy (EFT EM) as well as scanning electron microscopy (SEM) have been used to study the microstructure of materials related to hydrogen storage applications. Some of the results are compared with powder X-ray diffraction (PXD) data. A TbNiAl compound processed by the hydrogenation-disproportionation-desorption-recombination (HDDR) route has been studied using a combination of SEM, TEM and PXD. Information about the variations in the composition and surface topography in both disproportionation and recombination stages is given by the SEM backscattered electrons and secondary electrons images. The crystallites that have undergone the recombination process were found smaller in size. The sodium alanate, NaAIH4 is one of the most promising candidate materials for hydrogen storage. Ti additives are effective at reducing the reaction temperatures and improving the efficiency of the kinetics. The microstructure of NaAlH4 with TiF3 additive has been examined after the initial ball milling and after 15 cycles, using TEM, SEM and EDS. The effect of the additive on particle morphology, grain size and distribution of the phases has been studied. The additive has uneven distribution in the sample after initial ball milling. After 15 cycles, EDS maps show some combination of Ti with the alanate phase. No significant change in grain size of the Na/Al rich particles between the ball milled and 15 cycled sample was observed. The LiAlD4

  15. Scanning and Transmission Electron Microscopy of High Temperature Materials

    Science.gov (United States)

    1994-01-01

    Software and hardware updates to further extend the capability of the electron microscope were carried out. A range of materials such as intermetallics, metal-matrix composites, ceramic-matrix composites, ceramics and intermetallic compounds, based on refractory elements were examined under this research. Crystal structure, size, shape and volume fraction distribution of various phases which constitute the microstructures were examined. Deformed materials were studied to understand the effect of interfacial microstructure on the deformation and fracture behavior of these materials. Specimens tested for a range of mechanical property requirements, such as stress rupture, creep, low cycle fatigue, high cycle fatigue, thermomechanical fatigue, etc. were examined. Microstructural and microchemical stability of these materials exposed to simulated operating environments were investigated. The EOIM Shuttle post-flight samples were also examined to understand the influence of low gravity processing on microstructure. In addition, fractographic analyses of Nb-Zr-W, titanium aluminide, molybdenum silicide and silicon carbide samples were carried out. Extensive characterization of sapphire fibers in the fiber-reinforced composites made by powder cloth processing was made. Finally, pressure infiltration casting of metal-matrix composites was carried out.

  16. Thermal expansion model for multiphase electronic packaging materials

    International Nuclear Information System (INIS)

    Allred, B.E.; Warren, W.E.

    1991-01-01

    Control of thermal expansion is often necessary in the design and selection of electronic packages. In some instances, it is desirable to have a coefficient of thermal expansion intermediate between values readily attainable with single or two phase materials. The addition of a third phase in the form of fillers, whiskers, or fibers can be used to attain intermediate expansions. To help design the thermal expansion of multiphase materials for specific applications, a closed form model has been developed that accurately predicts the effective elastic properties of isotropic filled materials and transversely isotropic lamina. Properties of filled matrix materials are used as inputs to the lamina model to obtain the composite elastic properties as a function of the volume fraction of each phase. Hybrid composites with two or more fiber types are easily handled with this model. This paper reports that results for glass, quartz, and Kevlar fibers with beta-eucryptite filled polymer matrices show good agreement with experimental results for X, Y, and Z thermal expansion coefficients

  17. Scanning electron microscope autoradiography of critical point dried biological samples

    International Nuclear Information System (INIS)

    Weiss, R.L.

    1980-01-01

    A technique has been developed for the localization of isotopes in the scanning electron microscope. Autoradiographic studies have been performed using a model system and a unicellular biflagellate alga. One requirement of this technique is that all manipulations be carried out on samples that are maintained in a liquid state. Observations of a source of radiation ( 125 I-ferritin) show that the nuclear emulsion used to detect radiation is active under these conditions. Efficiency measurement performed using 125 I-ferritin indicate that 125 I-SEM autoradiography is an efficient process that exhibits a 'dose dependent' response. Two types of labeling methods were used with cells, surface labeling with 125 I and internal labeling with 3 H. Silver grains appeared on labeled cells after autoradiography, removal of residual gelatin and critical point drying. The location of grains was examined on a flagellated green alga (Chlamydomonas reinhardi) capable of undergoing cell fusion. Fusion experiments using labeled and unlabeled cells indicate that 1. Labeling is specific for incorporated radioactivity; 2. Cell surface structure is preserved in SEM autoradiographs and 3. The technique appears to produce reliable autoradiographs. Thus scanning electron microscope autoradiography should provide a new and useful experimental approach

  18. The status of electronic laboratory notebooks for chemistry and biology.

    Science.gov (United States)

    Taylor, Keith T

    2006-05-01

    Documenting an experiment in a way that ensures that the record can act as evidence to support a patent claim or to demonstrate compliance with the US Food and Drug Administration's (FDA's) predicate rules, puts demands on an electronic laboratory notebook (ELN) that are not trivial. The 1996 General Agreement on Tariffs and Trade (GATT) allowed notebook records that were generated outside of the US to be used to claim precedence in US patent claims. This agreement spurred interest in the development of ELNs in Europe. The pharmaceutical research process became dependent on computer systems during the latter part of the 1990s, and this also led to a wider interest in ELNs. More recently, the FDA began to encourage submissions in an all-electronic form, leading to great interest in the use of ELNs in development and manufacturing. As a result of these influences, the pharmaceutical industry is now actively pursuing ELN evaluations and implementations. This article describes some of the early efforts and the recent drivers for ELN adoption. The state of the ELN market in 2005 is also described.

  19. Source Identification of Human Biological Materials and Its Prospect in Forensic Science.

    Science.gov (United States)

    Zou, K N; Gui, C; Gao, Y; Yang, F; Zhou, H G

    2016-06-01

    Source identification of human biological materials in crime scene plays an important role in reconstructing the crime process. Searching specific genetic markers to identify the source of different human biological materials is the emphasis and difficulty of the research work of legal medical experts in recent years. This paper reviews the genetic markers which are used for identifying the source of human biological materials and studied widely, such as DNA methylation, mRNA, microRNA, microflora and protein, etc. By comparing the principles and methods of source identification of human biological materials using different kinds of genetic markers, different source of human biological material owns suitable marker types and can be identified by detecting single genetic marker or combined multiple genetic markers. Though there is no uniform standard and method for identifying the source of human biological materials in forensic laboratories at present, the research and development of a series of mature and reliable methods for distinguishing different human biological materials play the role as forensic evidence which will be the future development direction. Copyright© by the Editorial Department of Journal of Forensic Medicine.

  20. Physical methods for studying minerals and solid materials: X-ray, electron and neutron diffraction; scanning and transmission electron microscopy; X-ray, electron and ion spectrometry

    International Nuclear Information System (INIS)

    Eberhart, J.-P.

    1976-01-01

    The following topics are discussed: theoretical aspects of radiation-matter interactions; production and measurement of radiations (X rays, electrons, neutrons); applications of radiation interactions to the study of crystalline materials. The following techniques are presented: X-ray and neutron diffraction, electron microscopy, electron diffraction, X-ray fluorescence analysis, electron probe microanalysis, surface analysis by electron emission spectrometry (ESCA and Auger electrons), scanning electron microscopy, secondary ion emission analysis [fr

  1. Bioreceptivity evaluation of cementitious materials designed to stimulate biological growth.

    Science.gov (United States)

    Manso, Sandra; De Muynck, Willem; Segura, Ignacio; Aguado, Antonio; Steppe, Kathy; Boon, Nico; De Belie, Nele

    2014-05-15

    Ordinary Portland cement (OPC), the most used binder in construction, presents some disadvantages in terms of pollution (CO2 emissions) and visual impact. For this reason, green roofs and façades have gain considerable attention in the last decade as a way to integrate nature in cities. These systems, however, suffer from high initial and maintenance costs. An alternative strategy to obtain green facades is the direct natural colonisation of the cementitious construction materials constituting the wall, a phenomenon governed by the bioreceptivity of such material. This work aims at assessing the suitability of magnesium phosphate cement (MPC) materials to allow a rapid natural colonisation taking carbonated OPC samples as a reference material. For that, the aggregate size, the w/c ratio and the amount of cement paste of mortars made of both binders were modified. The assessment of the different bioreceptivities was conducted by means of an accelerated algal fouling test. MPC samples exhibited a faster fouling compared to OPC samples, which could be mainly attributed to the lower pH of the MPC binder. In addition to the binder, the fouling rate was governed by the roughness and the porosity of the material. MPC mortar with moderate porosity and roughness appears to be the most feasible material to be used for the development of green concrete walls. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Si quantum dots for nano electronics: From materials to applications

    International Nuclear Information System (INIS)

    Lombardo, S.; Spinella, C.; Rimini, E.

    2005-01-01

    This paper reviews the subject of Si quantum dots embedded in dielectric and its application to the realization of non volatile semiconductor memories. In the first part of the paper various approaches for the analysis of the materials through transmission electron microscopy (TEM) are critically discussed. The advantages coming from an innovative application of energy filtered TEM are put in clear evidence. The paper then focuses on the synthesis of the materials: two different methodologies for the realization of the dots, both based on chemical vapor deposition are described in detail, and physical models providing some understanding of the observed phenomenology are reported. We then discuss the application of this nano technology to the realization of the storage nodes in non volatile semiconductor memories. The following sections describe the electrical characteristics found in the test devices and some key aspects are described in terms of quantitative models. The test devices show several performance advantages, indicating that the approach is an excellent candidate for the realization of Flash memories of the nano electronic era

  3. Compression of pulsed electron beams for material tests

    Science.gov (United States)

    Metel, Alexander S.

    2018-03-01

    In order to strengthen the surface of machine parts and investigate behavior of their materials exposed to highly dense energy fluxes an electron gun has been developed, which produces the pulsed beams of electrons with the energy up to 300 keV and the current up to 250 A at the pulse width of 100-200 µs. Electrons are extracted into the accelerating gap from the hollow cathode glow discharge plasma through a flat or a spherical grid. The flat grid produces 16-cm-diameter beams with the density of transported per one pulse energy not exceeding 15 J·cm-2, which is not enough even for the surface hardening. The spherical grid enables compression of the beams and regulation of the energy density from 15 J·cm-2 up to 15 kJ·cm-2, thus allowing hardening, pulsed melting of the machine part surface with the further high-speed recrystallization as well as an explosive ablation of the surface layer.

  4. Electronic spectra and structures of some biologically important xanthines

    Science.gov (United States)

    Shukla, M. K.; Mishra, P. C.

    1994-08-01

    Electronic absorption and fluorescence spectra of aqueous solutions of xanthine, caffeine, theophylline and theobromine have been studied at different pH. The observed spectra have been interpreted in terms of neutral and ionic forms of the molecules with the help of molecular orbital calculations. At neutral and acidic pH, the spectra can be assigned to the corresponding most stable neutral forms, with the exception that the fluorescence of xanthine at acidic pH appears to originate from the lowest singlet excited state of a cation of the molecule. At alkaline pH, xanthine and theophylline exist mainly as their monoanions. In xanthine and theophylline at alkaline pH, fluorescence originates from the lowest singlet excited state of the corresponding anion. However, in caffeine and theobromine, even at alkaline pH, fluorescence belongs to the neutral species. On the whole, the properties of xanthine are quite different from those of the methyl xanthines.

  5. Photo electron emission microscopy of polarity-patterned materials

    International Nuclear Information System (INIS)

    Yang, W-C; Rodriguez, B J; Gruverman, A; Nemanich, R J

    2005-01-01

    This study presents variable photon energy photo electron emission microscopy (PEEM) of polarity-patterned epitaxial GaN films, and ferroelectric LiNbO 3 (LNO) single crystals and PbZrTiO 3 (PZT) thin films. The photo electrons were excited with spontaneous emission from the tunable UV free electron laser (FEL) at Duke University. We report PEEM observation of polarity contrast and measurement of the photothreshold of each polar region of the materials. For a cleaned GaN film with laterally patterned Ga- and N-face polarities, we found a higher photoelectric yield from the N-face regions compared with the Ga-face regions. Through the photon energy dependent contrast in the PEEM images of the surfaces, we can deduce that the threshold of the N-face region is less than ∼4.9 eV while that of the Ga-face regions is greater than 6.3 eV. In both LNO and PZT, bright emission was detected from the negatively poled domains, indicating that the emission threshold of the negative domain is lower than that of the positive domain. For LNO, the measured photothreshold was ∼4.6 eV at the negative domain and ∼6.2 eV at the positive domain, while for PZT, the threshold of the negative domain was less than 4.3 eV. Moreover, PEEM observation of the PZT surface at elevated temperatures displayed that the domain contrast disappeared near the Curie temperature of ∼300 deg. C. The PEEM polarity contrast of the polar materials is discussed in terms of internal screening from free carriers and defects and the external screening due to adsorbed ions

  6. Photo electron emission microscopy of polarity-patterned materials

    Science.gov (United States)

    Yang, W.-C.; Rodriguez, B. J.; Gruverman, A.; Nemanich, R. J.

    2005-04-01

    This study presents variable photon energy photo electron emission microscopy (PEEM) of polarity-patterned epitaxial GaN films, and ferroelectric LiNbO3 (LNO) single crystals and PbZrTiO3 (PZT) thin films. The photo electrons were excited with spontaneous emission from the tunable UV free electron laser (FEL) at Duke University. We report PEEM observation of polarity contrast and measurement of the photothreshold of each polar region of the materials. For a cleaned GaN film with laterally patterned Ga- and N-face polarities, we found a higher photoelectric yield from the N-face regions compared with the Ga-face regions. Through the photon energy dependent contrast in the PEEM images of the surfaces, we can deduce that the threshold of the N-face region is less than ~4.9 eV while that of the Ga-face regions is greater than 6.3 eV. In both LNO and PZT, bright emission was detected from the negatively poled domains, indicating that the emission threshold of the negative domain is lower than that of the positive domain. For LNO, the measured photothreshold was ~4.6 eV at the negative domain and ~6.2 eV at the positive domain, while for PZT, the threshold of the negative domain was less than 4.3 eV. Moreover, PEEM observation of the PZT surface at elevated temperatures displayed that the domain contrast disappeared near the Curie temperature of ~300 °C. The PEEM polarity contrast of the polar materials is discussed in terms of internal screening from free carriers and defects and the external screening due to adsorbed ions.

  7. Material Processing Opportunites Utilizing a Free Electron Laser

    Science.gov (United States)

    Todd, Alan

    1996-11-01

    Many properties of photocathode-driven Free Electron Lasers (FEL) are extremely attractive for material processing applications. These include: 1) broad-band tunability across the IR and UV spectra which permits wavelength optimization, depth deposition control and utilization of resonance phenomena; 2) picosecond pulse structure with continuous nanosecond spacing for optimum deposition efficiency and minimal collateral damage; 3) high peak and average radiated power for economic processing in quantity; and 4) high brightness for spatially defined energy deposition and intense energy density in small spots. We discuss five areas: polymer, metal and electronic material processing, micromachining and defense applications; where IR or UV material processing will find application if the economics is favorable. Specific examples in the IR and UV, such as surface texturing of polymers for improved look and feel, and anti-microbial food packaging films, which have been demonstrated using UV excimer lamps and lasers, will be given. Unfortunately, although the process utility is readily proven, the power levels and costs of lamps and lasers do not scale to production margins. However, from these examples, application specific cost targets ranging from 0.1=A2/kJ to 10=A2/kJ of delivered radiation at power levels from 10 kW to 500 kW, have been developed and are used to define strawman FEL processing systems. Since =46EL radiation energy extraction from the generating electron beam is typically a few percent, at these high average power levels, economic considerations dictate the use of a superconducting RF accelerator with energy recovery to minimize cavity and beam dump power loss. Such a 1 kW IR FEL, funded by the US Navy, is presently under construction at the Thomas Jefferson National Accelerator Facility. This dual-use device, scheduled to generate first light in late 1997, will test both the viability of high-power FELs for shipboard self-defense against cruise

  8. New improved method for evaluation of growth by food related fungi on biologically derived materials

    DEFF Research Database (Denmark)

    Bergenholtz, Karina P.; Nielsen, Per Væggemose

    2002-01-01

    Biologically derived materials, obtained as commercial and raw materials (Polylactate (PLA), Polyhydroxybutyrate (PHB), potato, wheat and corn starch) were tested for their ability to support fungal growth using a modified ASTM G21-96 (American Society for Testing and Materials) standard as well...

  9. Using Fourier transform IR spectroscopy to analyze biological materials

    Science.gov (United States)

    Baker, Matthew J; Trevisan, Júlio; Bassan, Paul; Bhargava, Rohit; Butler, Holly J; Dorling, Konrad M; Fielden, Peter R; Fogarty, Simon W; Fullwood, Nigel J; Heys, Kelly A; Hughes, Caryn; Lasch, Peter; Martin-Hirsch, Pierre L; Obinaju, Blessing; Sockalingum, Ganesh D; Sulé-Suso, Josep; Strong, Rebecca J; Walsh, Michael J; Wood, Bayden R; Gardner, Peter; Martin, Francis L

    2015-01-01

    IR spectroscopy is an excellent method for biological analyses. It enables the nonperturbative, label-free extraction of biochemical information and images toward diagnosis and the assessment of cell functionality. Although not strictly microscopy in the conventional sense, it allows the construction of images of tissue or cell architecture by the passing of spectral data through a variety of computational algorithms. Because such images are constructed from fingerprint spectra, the notion is that they can be an objective reflection of the underlying health status of the analyzed sample. One of the major difficulties in the field has been determining a consensus on spectral pre-processing and data analysis. This manuscript brings together as coauthors some of the leaders in this field to allow the standardization of methods and procedures for adapting a multistage approach to a methodology that can be applied to a variety of cell biological questions or used within a clinical setting for disease screening or diagnosis. We describe a protocol for collecting IR spectra and images from biological samples (e.g., fixed cytology and tissue sections, live cells or biofluids) that assesses the instrumental options available, appropriate sample preparation, different sampling modes as well as important advances in spectral data acquisition. After acquisition, data processing consists of a sequence of steps including quality control, spectral pre-processing, feature extraction and classification of the supervised or unsupervised type. A typical experiment can be completed and analyzed within hours. Example results are presented on the use of IR spectra combined with multivariate data processing. PMID:24992094

  10. Energy loss function for biological material: poly(CSP)

    International Nuclear Information System (INIS)

    Fung, A.Y.C.; Zaider, M.

    1994-01-01

    In this paper calculated cross sections are presented for the interaction of electrons with poly(CSP), a single-stranded chain that contains one cytosine sugar phosphate unit in the elementary cell. To model a single strand of helical DNA (e.g. the base stacking), the Watson-Crick model for the geometry of poly(CSP) has been used. The use, for computational simplicity, of a single, rather than a double stranded polynucleotide may be justified on the basis of previous calculations indicating that -to a good approximation - the electronic structure (other than excitation states) of complementary base pairs may be described as a superposition of the corresponding structures of the individual components. (Author)

  11. Biological and environmental reference materials in neutron activation analysis work

    International Nuclear Information System (INIS)

    Guinn, V.P.; Gavrilas, M.

    1990-01-01

    The great usefulness of reference materials, especially ones of certified elemental composition, is discussed with particular attention devoted to their use in instrumental neutron activation analysis (INAA) work. Their use, including both certified and uncertified values, in calculations made by the INAA Advance Prediction Computer Program (APCP) is discussed. The main features of the APCP are described, and mention is made of the large number of reference materials run on the APCP (including the new personal computer version of the program), with NBS Oyster Tissue SRM-1566 used as the principal examle. (orig.)

  12. Cluster model calculations of the solid state materials electron structure

    International Nuclear Information System (INIS)

    Pelikan, P.; Biskupic, S.; Banacky, P.; Zajac, A.; Svrcek, A.; Noga, J.

    1997-01-01

    Materials of the general composition ACuO 2 are the parent compounds of so called infinite layer superconductors. In the paper presented the electron structure of the compounds CaCuO 2 , SrCuO2, Ca 0.86 Sr 0.14 CuO2 and Ca 0.26 Sr 0.74 CuO 2 were calculated. The cluster models consisting of 192 atoms were computed using quasi relativistic version of semiempirical INDO method. The obtained results indicate the strong ionicity of Ca/Sr-O bonds and high covalency of Cu-bonds. The width of energy gap at the Fermi level increases as follows: Ca 0.26 Sr 0.74 CuO 2 0.86 Sr 0.14 CuO2 2 . This order correlates with the fact that materials of the composition Ca x Sr 1-x CuO 2 have have the high temperatures of the superconductive transition (up to 110 K). Materials partially substituted by Sr 2+ have also the higher density of states in the close vicinity at the Fermi level that ai the additional condition for the possibility of superconductive transition. It was calculated the strong influence of the vibration motions to the energy gap at the Fermi level. (authors). 1 tabs., 2 figs., 10 refs

  13. Synthetic Self-Assembled Materials in Biological Environments

    NARCIS (Netherlands)

    Versluis, F.; van Esch, J.H.; Eelkema, R.

    2016-01-01

    Synthetic self-assembly has long been recognized as an excellent approach for the formation of ordered structures on the nanoscale. Although the development of synthetic self-assembling materials has often been inspired by principles observed in nature (e.g., the assembly of lipids, DNA,

  14. 3D imaging by serial block face scanning electron microscopy for materials science using ultramicrotomy

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Teruo, E-mail: t.hashimoto@manchester.ac.uk; Thompson, George E.; Zhou, Xiaorong; Withers, Philip J.

    2016-04-15

    Mechanical serial block face scanning electron microscopy (SBFSEM) has emerged as a means of obtaining three dimensional (3D) electron images over volumes much larger than possible by focused ion beam (FIB) serial sectioning and at higher spatial resolution than achievable with conventional X-ray computed tomography (CT). Such high resolution 3D electron images can be employed for precisely determining the shape, volume fraction, distribution and connectivity of important microstructural features. While soft (fixed or frozen) biological samples are particularly well suited for nanoscale sectioning using an ultramicrotome, the technique can also produce excellent 3D images at electron microscope resolution in a time and resource-efficient manner for engineering materials. Currently, a lack of appreciation of the capabilities of ultramicrotomy and the operational challenges associated with minimising artefacts for different materials is limiting its wider application to engineering materials. Consequently, this paper outlines the current state of the art for SBFSEM examining in detail how damage is introduced during slicing and highlighting strategies for minimising such damage. A particular focus of the study is the acquisition of 3D images for a variety of metallic and coated systems. - Highlights: • The roughness of the ultramicrotomed block face of AA2024 in Al area was 1.2 nm. • Surface texture associated with chattering was evident in grains with 45° diamond knife. • A 76° rake angle minimises the stress on the block face. • Using the oscillating knife with a cutting speed of 0.04 mms{sup −1} minimised the surface texture. • A variety of material applications were presented.

  15. On the possibility of multiple utilization of Bowen's Kale for neutron activation analysis of biological materials

    International Nuclear Information System (INIS)

    Marinov, V.M.; Lazarova, M.S.; Mihajlov, M.I.; Apostolov, D.

    1977-01-01

    The results of investigations related to the multiple utilization of Bowen's Kale in developing neutron-activation methods for determining microelements in biological materials carried out in recent years are presented. Bowen's Kale might be used as: (1) experimental material in the development of a method and its verification, i.e. as a test for biological materials; (2) a material where experimental conditions might be optimized; (3) a material for investigating the accuracy, reproducibility and the limit of proof at experimental conditions already defined; (4) a monitor; (5) a multielement volume reference standard for a number of microelements during their simultaneous determination and (6) a standard for verifying the authenticity of the results obtained. In this manner, a reliable criterion for comparison of the potentialities, the accuracy, reproducibility, the limits of proof and the authenticity of the neutron-activation methods of determining microelements in biological materials is introduced. (author)

  16. 3D electron tomography of biological photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Butz, Benjamin; Winter, Benjamin; Vieweg, Benito; Knoke, Isabel; Spallek, Stefanie; Spiecker, Erdmann [CENEM, Universitaet Erlangen-Nuernberg (Germany); Schroeder-Turk, Gerd; Mecke, Klaus [Theoretische Physik I, Universitaet Erlangen-Nuernberg (Germany)

    2011-07-01

    Photonic crystals, i.e. periodical nanostructures of materials with different dielectric constants, are highly interesting for applications in optics, optoelectronics, and sensing. By tailoring the geometrical parameters radically different and improved optical properties (e.g., optical band-gap structure, extreme refractive indices, or high anisotropy) can be achieved. Naturally occurring photonic crystals, like butterfly scales, exoskeletons of insects (chitin), or seashells (nacre), can serve as model systems for understanding the relationship between structure and optical properties. Butterfly scales are studied by TEM using a FEI Titan{sup 3} 80-300 instrument. An optimized FIB technique or ultramicrotome sectioning were used to prepare the sensitive specimens with desired thickness. Since the periodical structures have dimensions on the sub-{mu}m scale, HAADF-STEM tomography was employed for obtaining extended tilt series under conditions of atomic-number sensitive imaging. Since the solid crystal consists of chemically homogeneous chitin while the pores are unfilled, the distinct contrast in the images can easily be interpreted in terms of the local projected mass density allowing to reconstruct the chitin distribution within the optical unit cell of the scales with high 3D resolution.

  17. Analysis of biological materials using a nuclear microprobe

    Science.gov (United States)

    Mulware, Stephen Juma

    The use of nuclear microprobe techniques including: Particle induced x-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) for elemental analysis and quantitative elemental imaging of biological samples is especially useful in biological and biomedical research because of its high sensitivity for physiologically important trace elements or toxic heavy metals. The nuclear microprobe of the Ion Beam Modification and Analysis Laboratory (IBMAL) has been used to study the enhancement in metal uptake of two different plants. The roots of corn (Zea mays) have been analyzed to study the enhancement of iron uptake by adding Fe (II) or Fe(III) of different concentrations to the germinating medium of the seeds. The Fe uptake enhancement effect produced by lacing the germinating medium with carbon nanotubes has also been investigated. The aim of this investigation is to ensure not only high crop yield but also Fe-rich food products especially from calcareous soil which covers 30% of world's agricultural land. The result will help reduce iron deficiency anemia, which has been identified as the leading nutritional disorder especially in developing countries by the World Health Organization. For the second plant, Mexican marigold (Tagetes erecta ), the effect of an arbuscular mycorrhizal fungi (Glomus intraradices ) for the improvement of lead phytoremediation of lead contaminated soil has been investigated. Phytoremediation provides an environmentally safe technique of removing toxic heavy metals (like lead), which can find their way into human food, from lands contaminated by human activities like mining or by natural disasters like earthquakes. The roots of Mexican marigold have been analyzed to study the role of arbuscular mycorrhizal fungi in enhancement of lead uptake from the contaminated rhizosphere.

  18. Factors associated with occupational exposure to biological material among nursing professionals.

    Science.gov (United States)

    Negrinho, Nádia Bruna da Silva; Malaguti-Toffano, Silmara Elaine; Reis, Renata Karina; Pereira, Fernanda Maria Vieira; Gir, Elucir

    2017-01-01

    to identify factors associated with occupational exposure to biological material among nursing professionals. a cross-sectional study was conducted in a high complexity hospital of a city in the state of São Paulo, Brazil. Nursing professionals were interviewed from March to November 2015. All ethical aspects were observed. among the 226 professionals interviewed, 17.3% suffered occupational exposure to potentially contaminated biological material, with 61.5% being percutaneous. Factors such as age (p=0.003), professional experience in nursing (p=0.015), and experience at the institution (p=0.032) were associated with the accidents with biological material. most accidents with biological material among nursing professionals were percutaneous. Age, professional experience, and experience at the institution were considered factors associated with occupational exposure.

  19. Low cost materials of construction for biological processes: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-13

    The workshop was held, May 1993 in conjunction with the 15th Symposium on Biotechnology for Fuels and Chemicals. The purpose of this workshop was to present information on the biomass to ethanol process in the context of materials selection and through presentation and discussion, identify promising avenues for future research. Six technical presentations were grouped into two sessions: process assessment and technology assessment. In the process assessment session, the group felt that the pretreatment area would require the most extensive materials research due the complex chemical, physical and thermal environment. Discussion centered around the possibility of metals being leached into the process stream and their effect on the fermentation mechanics. Linings were a strong option for pretreatment assuming the economics were favorable. Fermentation was considered an important area for research also, due to the unique complex of compounds and dual phases present. Erosion in feedstock handling equipment was identified as a minor concern. In the technology assessment session, methodologies in corrosion analysis were presented in addition to an overview of current coatings/linings technology. Widely practiced testing strategies, including ASTM methods, as well as novel procedures for micro-analysis of corrosion were discussed. Various coatings and linings, including polymers and ceramics, were introduced. The prevailing recommendations for testing included keeping the testing simple until the problem warranted a more detailed approach and developing standardized testing procedures to ensure the data was reproducible and applicable. The need to evaluate currently available materials such as coatings/linings, carbon/stainless steels, or fiberglass reinforced plastic was emphasized. It was agreed that economic evaluation of each material candidate must be an integral part of any research plan.

  20. Impacts of Insufficient Instructional Materials on Teaching Biology: Higher Education Systems in Focus

    Science.gov (United States)

    Edessa, Sutuma

    2017-01-01

    The purpose of this study was to assess and determine impacts of insufficient instructional materials and ineffective lesson delivery methods on teaching in biology higher education. The participants of this study were 60 trainees who graduated in Bachelor of Sciences from eight public universities in majoring biology. Data for the study was…

  1. Contained scanning electron microscope facility for examining radioactive materials

    International Nuclear Information System (INIS)

    Hsu, C.W.

    1986-03-01

    At the Savannah River Laboratory (SRL) radioactive solids are characterized with a scanning electron microscope (SEM) contained in a glove box. The system includes a research-grade Cambridge S-250 SEM, a Tracor Northern TN-5500 x-ray and image analyzer, and a Microspec wavelength-dispersive x-ray analyzer. The containment facility has a glove box train for mounting and coating samples, and for housing the SEM column, x-ray detectors, and vacuum pumps. The control consoles of the instruments are located outside the glove boxes. This facility has been actively used since October 1983 for high alpha-activity materials such as plutonium metal and plutonium oxide powders. Radioactive defense waste glasses and contaminated equipment have also been examined. During this period the facility had no safety-related incidents, and personnel radiation exposures were maintained at less than 100 mrems

  2. Irradiation of aluminium alloy materials with electron beam

    International Nuclear Information System (INIS)

    Konno, Osamu; Masumoto, Kazuyoshi

    1982-01-01

    It is a theme with a room for discussion to employ the stainless steel composed of longer half-life materials for the vacuum system of accelerators, from the viewpoint of radiation exposure. Therefore, it is desirable to use aluminium of shorter half-life in place of stainless steel. As a result of investigation on the above theme in the 1.2 GeV electron linac project in Tohoku University, it has been concluded that aluminium alloy vacuum chambers can reduce exposure dose by about one or two figures as compared with stainless steel ones. Of course, aluminium alloy contains trace amounts of Mg, Si, Ti, Cr, Mn, Fe, Zn, Cu and others. Therefore, four kinds of aluminium alloy considered to be usable have been examined for induced radioactivity by electron beam irradiation. Stainless steel SUS 304 has been also irradiated for comparison. Radiation energy has been 30 MeV and 200 MeV. When stainless steel and aluminium alloy were compared, aluminium alloy was very effective for reducing surface dose in low energy irradiation. In 200 MeV irradiation, the dose ratio of aluminium alloy to stainless steel became 1/30 to 1/100 after one week, though the dose difference between these two materials became smaller in 100 days or more after irradiation. If practical inspection and repair are implemented during the period from a few days to one week after shutdown, the aluminium alloy is preferable for exposure dose reduction even in high energy irradiation. (Wakatsuki, Y.)

  3. Characterization of high Tc materials and devices by electron microscopy

    National Research Council Canada - National Science Library

    Browning, Nigel D; Pennycook, Stephen J

    2000-01-01

    ..., and microanalysis by scanning transmission electron microscopy. Ensuing chapters examine identi®cation of new superconducting compounds, imaging of superconducting properties by lowtemperature scanning electron microscopy, imaging of vortices by electron holography and electronic structure determination by electron energy loss spectro...

  4. Successful application of Low Voltage Electron Microscopy to practical materials problems

    International Nuclear Information System (INIS)

    Bell, David C.; Mankin, Max; Day, Robert W.; Erdman, Natasha

    2014-01-01

    Low-voltage High-Resolution Electron Microscopy (LVHREM) has several advantages, including increased cross-sections for inelastic and elastic scattering, increased contrast per electron, decreased delocalization effects and reduced knock-on damage. Imaging at differing voltages has shown advantages for imaging materials that are knock-on damage sensitive. We show experimentally that different materials systems benefit from low voltage high-resolution microscopy. There are advantages for imaging single layer materials such as graphene at below the knock-on threshold; we present an example of imaging a graphene sheet at 40 kV. We have also examined mesoporous silica decorated with Pd nanoparticles and carbon black functionalized with Pd/Pt nanoparticles. In these cases we show that the lower voltage imaging maintains the structure of the surrounding matrix during imaging, whereas aberration correction provides the higher resolution for imaging the nanoparticle lattice. Perhaps surprisingly we show that zeolites damage preferentially by ionization effects (radiolysis). The current literature suggests that below incident energies of 40 kV the damage is mainly radiolitic, whereas at incident energies above 200 kV the knock-on damage and material sputtering will be the dominant effect. Our experimental observations support this conclusion and the effects we have observed at 40 kV are not indicative of knock-on damage. Other nanoscale materials such as thin silicon nanowires also benefit from lower voltage imaging. LVHREM imaging provides an excellent option to avoid beam damage to nanowires; our results suggest that LVHREM is suitable for nanowire-biological composites. Our experimental observations serve as a clear demonstration that even at 40 keV accelerating voltage, LVHREM can be used without inducing beam damage to locate dislocations and other crystalline defects, which may have adverse effects on nanowire device performance. Low voltage operation will likely

  5. Dosimetry using environmental and biological materials. Final report

    International Nuclear Information System (INIS)

    Haskell, E.; Kenner, G.; Hayes, R.

    1998-02-01

    This report summarizes a five year effort to improve the sensitivity and reliability of retrospective dosimetry methods, to collaborate with laboratories engaged in related research and to share the technology with startup laboratories seeking similar capabilities. This research program has focused on validation of electron paramagnetic resonance (EPR) as a dosimetry tool and on optimization of the technique by reducing the lower limits of detection, simplifying the process of sample preparation and analysis and speeding analysis to allow greater throughput in routine measurement situations. The authors have investigated the dosimetric signal of hard tissues in enamel, deorganified dentin, synthetic carbonated apatites and synthetic hydroxyapatite. This research has resulted in a total of 27 manuscripts which have been published, are in press, or have been submitted for publication. Of these manuscripts, 14 are included in this report and were indexed separately for inclusion in the data base

  6. Development of biological functional material and product from Nelumbo nucifera

    International Nuclear Information System (INIS)

    Jeong, Il Yun; Park, Yong Dae; Jin, Chang Hyun; Choi, Dae Seong

    2008-01-01

    The solvent extracts of Nelumbo nucifera G. were investigated for the activities of antioxidant, whitening, anti-wrinkle and antimicrobial effects to apply as a functional ingredient for cosmetic products. The electron donating ability of irradiated NN-L extract was above 85% at the concentration of 50ppm. The superoxide dismutase(SOD)-like activity of irradiated NN-L extract was about 76% at 1,000ppm concentration. The xanthine oxidase inhibitory effect of irradiated NN-L extract was about 15% at 1,000ppm. The tyrosinase inhibitory effect of irradiated NN-L extract was about 18% at 1,000ppm. Anti-wrinkle effect, the elastase inhibition activity of irradiated NN-L extract was about 45% at 1,000ppm concentration. All these findings suggested that Nelumbo nucifera G. has a great potential as a cosmeceutical ingredient

  7. Development of biological functional material and product from Nelumbo nucifera

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Il Yun; Park, Yong Dae; Jin, Chang Hyun; Choi, Dae Seong

    2008-01-15

    The solvent extracts of Nelumbo nucifera G. were investigated for the activities of antioxidant, whitening, anti-wrinkle and antimicrobial effects to apply as a functional ingredient for cosmetic products. The electron donating ability of irradiated NN-L extract was above 85% at the concentration of 50ppm. The superoxide dismutase(SOD)-like activity of irradiated NN-L extract was about 76% at 1,000ppm concentration. The xanthine oxidase inhibitory effect of irradiated NN-L extract was about 15% at 1,000ppm. The tyrosinase inhibitory effect of irradiated NN-L extract was about 18% at 1,000ppm. Anti-wrinkle effect, the elastase inhibition activity of irradiated NN-L extract was about 45% at 1,000ppm concentration. All these findings suggested that Nelumbo nucifera G. has a great potential as a cosmeceutical ingredient.

  8. Analysis of hazardous biological material by MALDI mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    KL Wahl; KH Jarman; NB Valentine; MT Kingsley; CE Petersen; ST Cebula; AJ Saenz

    2000-03-21

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-MS) has become a valuable tool for analyzing microorganisms. The speed with which data can be obtained from MALDI-MS makes this a potentially important tool for biological health hazard monitoring and forensic applications. The excitement in the mass spectrometry community in this potential field of application is evident by the expanding list of research laboratories pursuing development of MALDI-MS for bacterial identification. Numerous research groups have demonstrated the ability to obtain unique MALDI-MS spectra from intact bacterial cells and bacterial cell extracts. The ability to differentiate strains of the same species has been investigated. Reproducibility of MALDI-MS spectra from bacterial species under carefully controlled experimental conditions has also been demonstrated. Wang et al. have reported on interlaboratory reproducibility of the MALDI-MS analysis of several bacterial species. However, there are still issues that need to be addressed, including the careful control of experimental parameters for reproducible spectra and selection of optimal experimental parameters such as solvent and matrix.

  9. Determination of trace elements in electronic materials by NAA

    International Nuclear Information System (INIS)

    Kobayashi, Kenji

    1986-01-01

    Trace amounts of elements in electronic materials were determined by instrumental neutron activation analysis (INAA), re-activation analysis and substoichiometric radioactivation analysis using gamma-ray spectrometry. Ten elements (Cr, Cu, Fe, Zn, Co, Eu, Ir, Sb, Sc, Tb) in gallium arsenide single crystal were determined by INAA and substoichiometric radioactivation analysis. Trace level of chromium (10 13 atoms/cm 3 ) and zinc (10 14 atoms/cm 3 ) in gallium arsenide single crystal were determined by INAA. The chromium concentrations in horizontal Bridgmangrown semi-insulating gallium arsenide ingot were ranged from 1.2 x 10 16 atoms/cm 3 at seed end to 3.5 x 10 16 atoms/cm 3 at tail end. The trace determinations of iron (10 14 atoms/cm 3 ) and copper (10 14 atoms/cm 3 ) in silicon, gallium arsenide and indium phoshide single crystals were carried out by substoichiometric radioactivation analysis. The reactivation analysis for the multielement determination of indium phosphide single crystal was carried out and nineteen elements were determined simultaneously by gamma-ray spectrometry. Eleven elements (Ag, As, Br, Co, Cr, Fe, K, Mn, Sb, Sc, Zn) in four NIES standard reference materials (Pond Sediment, Chlorella, Mussel and Tea Leaves) and seven elements (Co, Cr, Eu, Fe, Sc, Tb, Yb) in two NBS glasses (SRM-615 and SRM-613) were determined by INAA and substoichiometric radioactivation analysis and the analytical results obtained by the methods were in good agreement with certified values by NIES and NBS. (author)

  10. Development of electronic tattoo for pulse rate monitoring: Materials perspective

    Science.gov (United States)

    Shinde, Shilpa Vikas; Sonavane, S. S.

    2018-05-01

    In India, there is a growing concern of the heart diseases and deaths due to heart failure. The severity of the problem can be minimised by efficient heart rate monitoring which can be used to provide before time caution to cater heart attack. Wearable sensor can be designed to sense the pulse. The sensor can be either placed near to heart or on the wrist to sense pulses and send pulse signals to the doctors. Such sensor should adhere to the skin for sufficiently long period without causing etching to the patient. It should also be bendable and stretchable like skin. This paper is a part of the research work carried out to develop patch type sensor, which is termed as Electronic Tattoo (ET). In pursuit for development of ET, we came across various designs and candidate materials which can be used for the ET. Thus, in this paper, we describe the process of selecting best suited method and material for the ET. It may also be noted that the sensor development is governed by the prevailing IEEE 802.15.6 standard.

  11. Photon-Electron Interactions in Dirac Quantum Materials

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xiaodong [Univ. of Washington, Seattle, WA (United States). Dept. of Material Science and Engineering

    2017-11-10

    The objective of this proposal was to explore the fundamental light-matter interactions in a new class of Dirac quantum materials, atomically thin transition metal dichalcogenides (TMDs). Monolayer TMDs are newly discovered two-dimensional semiconductors with direct bandgap. Due to their hexagonal lattice structure, the band edge localizes at corner of Brillouin zone, i.e. “Dirac valleys”. This gives the corresponding electron states a “valley index” (or pseudospin) in addition to the real spin. Remarkably, the valley pseudospins have circularly polarized optical selection rules, providing the first solid state system for dynamic control of the valley degree of freedom. During this award, we have developed a suite of advanced nano-optical spectroscopy tools in the investigation and manipulation of charge, spin, and valley degrees of freedom in monolayer semiconductors. Emerging physical phenomena, such as quantum coherence between valley pseudospins, have been demonstrated for the first time in solids. In addition to monolayers, we have developed a framework in engineering, formulating, and understanding valley pseudospin physics in 2D heterostructures formed by different monolayer semiconductors. We demonstrated long-lived valley-polarized interlayer excitons with valley-dependent many-body interaction effects. These works push the research frontier in understanding the light-matter interactions in atomically-thin quantum materials for protentional transformative energy technologies.

  12. A short comparison of electron and proton transfer processes in biological systems

    International Nuclear Information System (INIS)

    Bertrand, Patrick

    2005-01-01

    The main differences between electron and proton transfers that take place in biological systems are examined. The relation between the distance dependence of the rate constant and the mass of the transferred particle is analyzed in detail. Differences between the two processes have important consequences at the experimental level, which are discussed. The various mechanisms that ensure the coupling between electron and proton transfers are briefly described

  13. Dynamical "in situ" observation of biological samples using variable pressure scanning electron microscope

    Czech Academy of Sciences Publication Activity Database

    Neděla, Vilém

    2008-01-01

    Roč. 126, - (2008), 012046:1-4 ISSN 1742-6588. [Electron Microscopy and Analysis Group Conference 2007 (EMAG 2007). Glasgow, 03.09.2007-07.09.2007] R&D Projects: GA ČR(CZ) GA102/05/0886; GA AV ČR KJB200650602 Institutional research plan: CEZ:AV0Z20650511 Keywords : biological sample * VP-SEM * dynamical experiments Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  14. Towards native-state imaging in biological context in the electron microscope

    Science.gov (United States)

    Weston, Anne E.; Armer, Hannah E. J.

    2009-01-01

    Modern cell biology is reliant on light and fluorescence microscopy for analysis of cells, tissues and protein localisation. However, these powerful techniques are ultimately limited in resolution by the wavelength of light. Electron microscopes offer much greater resolution due to the shorter effective wavelength of electrons, allowing direct imaging of sub-cellular architecture. The harsh environment of the electron microscope chamber and the properties of the electron beam have led to complex chemical and mechanical preparation techniques, which distance biological samples from their native state and complicate data interpretation. Here we describe recent advances in sample preparation and instrumentation, which push the boundaries of high-resolution imaging. Cryopreparation, cryoelectron microscopy and environmental scanning electron microscopy strive to image samples in near native state. Advances in correlative microscopy and markers enable high-resolution localisation of proteins. Innovation in microscope design has pushed the boundaries of resolution to atomic scale, whilst automatic acquisition of high-resolution electron microscopy data through large volumes is finally able to place ultrastructure in biological context. PMID:19916039

  15. Small-scale laser based electron accelerators for biology and medicine: a comparative study of the biological effectiveness

    Science.gov (United States)

    Labate, Luca; Andreassi, Maria Grazia; Baffigi, Federica; Basta, Giuseppina; Bizzarri, Ranieri; Borghini, Andrea; Candiano, Giuliana C.; Casarino, Carlo; Cresci, Monica; Di Martino, Fabio; Fulgentini, Lorenzo; Ghetti, Francesco; Gilardi, Maria Carla; Giulietti, Antonio; Köster, Petra; Lenci, Francesco; Levato, Tadzio; Oishi, Yuji; Russo, Giorgio; Sgarbossa, Antonella; Traino, Claudio; Gizzi, Leonida A.

    2013-05-01

    Laser-driven electron accelerators based on the Laser Wakefield Acceleration process has entered a mature phase to be considered as alternative devices to conventional radiofrequency linear accelerators used in medical applications. Before entering the medical practice, however, deep studies of the radiobiological effects of such short bunches as the ones produced by laser-driven accelerators have to be performed. Here we report on the setup, characterization and first test of a small-scale laser accelerator for radiobiology experiments. A brief description of the experimental setup will be given at first, followed by an overview of the electron bunch characterization, in particular in terms of dose delivered to the samples. Finally, the first results from the irradiation of biological samples will be briefly discussed.

  16. Precision of neutron activation analysis for environmental biological materials

    International Nuclear Information System (INIS)

    Hamaguchi, Hiroshi; Iwata, Shiro; Koyama, Mutsuo; Sasajima, Kazuhisa; Numata, Yuichi.

    1977-01-01

    Between 1973 and 1974 a special committee ''Research on the application of neutron activation analysis to the environmental samples'' had been organized at the Research Reactor Institute, Kyoto University. Eleven research groups composed mainly of the committee members cooperated in the intercomparison programme of the reactor neutron activation analysis of NBS standard reference material, 1571 Orchard Leaves and 1577 Bovine Liver. Five different type of reactors were used for the neutron irradiation; i.e. KUR reactor of the Research Reactor Institute, Kyoto University, TRIGA MARK II reactor of the Institute for Atomic Energy, Rikkyo University, and JRR-2, JRR-3, JRR-4 reactor of Japan Atomic Energy Research Institute. Analyses were performed mainly by instrumental method. Precision of the analysis of 23 elements in Orchard Leaves and 13 elements in Bovine Liver presented by the different research groups was shown in table 4 and 5, respectively. The coefficient of variation for these elements was from several to -- 30 percent. Averages given to these elements agreed well with the NBS certified or reference values. Thus, from the practical point of view for the routine multielement analysis of environmental samples, the validity of the instrumental neutron activation technique for this purpose has been proved. (auth.)

  17. Is analysis of biological materials with nm spatial resolution possible?

    International Nuclear Information System (INIS)

    Warley, Alice

    2006-01-01

    Cells are bounded by a membrane, the plasma membrane, subcompartments within cells are also delineated by membranes, these membranes contain transporters that regulate the flow of ions across them. Fluxes of ions across the membranes underlie many of the basic properties of living material such as excitability and movement. Breakdown of membrane function ultimately leads to cell death. EM microanalysis has been instrumental in gaining understanding of how changes in element distribution affect cell behaviour and cell survival. The main problem that biologists face in undertaking such studies is that of specimen preparation. Cells consist mainly of water that needs to be either removed or stabilised before analysis can take place. Cryotechniques, fixation by rapid freezing followed by sectioning at low temperatures and freeze-drying of the sections have proved to be a reliable method for the study of intracellular element concentrations. These techniques have been used to show that elements are confined in different compartments within cells and produced results to support a new theory on the mechanism by which neutrophils kill bacteria. They have also shown that disturbance of the ionic content of mitochondria is one of the first signs in the pathway to cell death

  18. Sample preparation techniques of biological material for isotope analysis

    International Nuclear Information System (INIS)

    Axmann, H.; Sebastianelli, A.; Arrillaga, J.L.

    1990-01-01

    Sample preparation is an essential step in all isotope-aided experiments but often it is not given enough attention. The methods of sample preparation are very important to obtain reliable and precise analytical data and for further interpretation of results. The size of a sample required for chemical analysis is usually very small (10mg-1500mg). On the other hand the amount of harvested plant material from plots in a field experiment is often bulky (several kilograms) and the entire sample is too large for processing. In addition, while approaching maturity many crops show not only differences in physical consistency but also a non-uniformity in 15 N content among plant parts, requiring a plant fractionation or separation into parts (vegetative and reproductive) e.g. shoots and spikes, in case of small grain cereals, shoots and pods in case of grain legumes and tops and roots or beets (including crown) in case of sugar beet, etc. In any case the ultimate goal of these procedures is to obtain representative subsample harvested from greenhouse or field experiments for chemical analysis. Before harvesting an isotopic-aided experiment the method of sampling has to be selected. It should be based on the type of information required in relation to the objectives of the research and the availability of resources (staff, sample preparation equipment, analytical facilities, chemicals and supplies, etc.). 10 refs, 3 figs, 3 tabs

  19. Maximum concentrations at work and maximum biologically tolerable concentration for working materials 1991

    International Nuclear Information System (INIS)

    1991-01-01

    The meaning of the term 'maximum concentration at work' in regard of various pollutants is discussed. Specifically, a number of dusts and smokes are dealt with. The valuation criteria for maximum biologically tolerable concentrations for working materials are indicated. The working materials in question are corcinogeneous substances or substances liable to cause allergies or mutate the genome. (VT) [de

  20. Temperature response of biological materials to pulsed non-ablative CO2 laser irradiation

    NARCIS (Netherlands)

    Brugmans, M. J.; Kemper, J.; Gijsbers, G. H.; van der Meulen, F. W.; van Gemert, M. J.

    1991-01-01

    This paper presents surface temperature responses of various tissue phantoms and in vitro and in vivo biological materials in air to non-ablative pulsed CO2 laser irradiation, measured with a thermocamera. We studied cooling off behavior of the materials after a laser pulse, to come to an

  1. Determination of trace elements in biological material by neutron activation analysis

    International Nuclear Information System (INIS)

    Tran Van, L.; Teherani, D.K.

    1989-01-01

    Eighteen trace elements in biological materials [grass (Imperata cylindrica), mimosa plant (Mimosa pudica), rice] by neutron activation method were determined. In the comparative analysis the content of the same element was different in each material, although they were collected at the same place and the same sampling method was applied. (author) 4 refs.; 1 fig.; 1 tab

  2. Analysis of biological materials by RBS and PIXE methods

    International Nuclear Information System (INIS)

    Latuszynski, A.; Maczka, D.; Kobzev, A. P.

    2002-01-01

    A problem of the exact determination of the element concentration in different substances is of essential significance, especially in medical, biological, as well as environment protection investigations. For this purpose some chemical and physical methods are used such as very sensitive and precise techniques: PIXE and RBS. The main advantage of those methods is the sensitivity of ppm level and very small sample amount necessary for carrying out the investigations. In this article the investigation results obtained by PIXE and RBS methods for the metal contents in cow milk (18 various samples were studied) as well as the heavy metal admixtures in the brain of the living domestic animals (6 cows, 6 dogs and 17 rats) are presented. The samples were prepared for the analysis in a liofilization process, then they were mixed with spectral pure graphite. The PIXE and RBS investigations were performed using a proton beam of about 2 mm diameter, intensity of about 10 nA and energy of 2.5 MeV from the Van-de-Graaff generator, FLNP, JINR, Dubna. The measurements of the characteristic spectrum were carried out by means of a Si (Li) detector with the resolution of 200 eV at the energy of 6,4 keV. Generally, in all samples of milk and brain we could identify 20 elements, among them 13 (C, N, O, P, Cl, K, Ca, Fe, Cu, Zn. Br, Rb, Sr) appeared in all of the studied samples. The difference in the concentration of the most of those elements between samples was in the range of 15 - 20 %. This indicates a good accuracy of the used methods of measurement. Especially our attention was paid to the presence of Sr, Rb and Br, practically in all the milk samples. This fact requires further investigations. Such elements as Pb, As, Ni, Co, Mn, V and Ti were found in some samples, including all samples coming from regions of a high urbanization. It is characteristic that the milk samples coming from villages located considerably far-away from cities and from communication tracks, practically

  3. [Prevention of occupational accidents with biological material as per Green and Kreuter Model].

    Science.gov (United States)

    Manetti, Marcela Luisa; da Costa, João Carlos Souza; Marziale, Maria Helena Palucci; Trovó, Marli Elisa

    2006-03-01

    This study aimed at diagnosing the occurrence of occupational accidents deriving from exposition to biological substance among workers of a hospital from São Paulo, Brazil, analyzing the adopted safety measures and elaborating a flowchart of preventive actions according to the Health Promotion Model by Green and Kreuter. It is an exploratory study with data collected electronically from the website REPAT - Electronic Network for the Prevention of Occupational Accidents with biological substances. The strategy used by the hospital did not reduce the injures. Results were used to elaborate a flowchart of preventive actions in order to improve the workers' quality of life.

  4. Sampling and sample preparation methods for the analysis of trace elements in biological material

    International Nuclear Information System (INIS)

    Sansoni, B.; Iyengar, V.

    1978-05-01

    The authors attempt to give a most systamtic possible treatment of the sample taking and sample preparation of biological material (particularly in human medicine) for trace analysis (e.g. neutron activation analysis, atomic absorption spectrometry). Contamination and loss problems are discussed as well as the manifold problems of the different consistency of solid and liquid biological materials, as well as the stabilization of the sample material. The process of dry and wet ashing is particularly dealt with, where new methods are also described. (RB) [de

  5. Monitoring of biological odour filtration in closed environments with olfactometry and an electronic nose

    NARCIS (Netherlands)

    Willers, H.C.; Gijsel, de P.; Ogink, N.W.M.; Amico, D' A.; Martinelli, E.; Natale, Di C.; Ras, van N.; Waarde, van der J.

    2004-01-01

    Air treatment with a compact biological membrane filter, and air quality monitoring with an electronic nose were tested in the laboratory on air from a cage containing six mice. Additional analyses of air to and from the filter were performed using olfactometry and ammonia and hydrogen sulphide gas

  6. Elemental analysis of biological materials. Current problems and techniques with special reference to trace elements

    International Nuclear Information System (INIS)

    1980-01-01

    Selected techniques were reviewed for the assay of trace and minor elements in biological materials. Other relevant information is also presented on the need for such analyses, sampling, sample preparation and analytical quality control. In order to evaluate and compare the applicability of the various analytical techniques on a meaningful and objective basis, the materials chosen for consideration were intended to be typical of a wide range of biological matrics of different elemental compositions, namely Bowen's kale, representing a plant material, and NBS bovine liver, IAEA animal muscle, and blood serum, representing animal tissues. The subject is reviewed under the following headings: on the need for trace element analyses in the life sciences (4 papers); sampling and sample preparation for trace element analysis (2 papers); analytical techniques for trace and minor elements in biological materials (7 papers); analytical quality control (2 papers)

  7. Electronic transport in amorphous phase-change materials

    Energy Technology Data Exchange (ETDEWEB)

    Luckas, Jennifer Maria

    2012-09-14

    Phase change materials combine a pronounced contrast in resistivity and reflectivity between their disordered amorphous and ordered crystalline state with very fast crystallization kinetics. Due to this exceptional combination of properties phase-change materials find broad application in non-volatile optical memories such as CD, DVD or Bluray Disc. Furthermore, this class of materials demonstrates remarkable electrical transport phenomena in their disordered state, which have shown to be crucial for their application in electronic storage devices. The threshold switching phenomenon denotes the sudden decrease in resistivity beyond a critical electrical threshold field. The threshold switching phenomenon facilitates the phase transitions at practical small voltages. Below this threshold the amorphous state resistivity is thermally activated and is observed to increase with time. This effect known as resistance drift seriously hampers the development of multi-level storage devices. Hence, understanding the physical origins of threshold switching and resistance drift phenomena is crucial to improve non-volatile phase-change memories. Even though both phenomena are often attributed to localized defect states in the band gap, the defect state density in amorphous phase-change materials has remained poorly studied. Starting from a brief introduction of the physics of phase-change materials this thesis summarizes the most important models behind electrical switching and resistance drift with the aim to discuss the role of localized defect states. The centerpiece of this thesis is the investigation of defects state densities in different amorphous phase-change materials and electrical switching chalcogenides. On the basis of Modulated Photo Current (MPC) Experiments and Photothermal Deflection Spectroscopy, a sophisticated band model for the disordered phase of the binary phase-change alloy GeTe has been developed. By this direct experimental approach the band-model for a

  8. Electronic transport in amorphous phase-change materials

    International Nuclear Information System (INIS)

    Luckas, Jennifer Maria

    2012-01-01

    Phase change materials combine a pronounced contrast in resistivity and reflectivity between their disordered amorphous and ordered crystalline state with very fast crystallization kinetics. Due to this exceptional combination of properties phase-change materials find broad application in non-volatile optical memories such as CD, DVD or Bluray Disc. Furthermore, this class of materials demonstrates remarkable electrical transport phenomena in their disordered state, which have shown to be crucial for their application in electronic storage devices. The threshold switching phenomenon denotes the sudden decrease in resistivity beyond a critical electrical threshold field. The threshold switching phenomenon facilitates the phase transitions at practical small voltages. Below this threshold the amorphous state resistivity is thermally activated and is observed to increase with time. This effect known as resistance drift seriously hampers the development of multi-level storage devices. Hence, understanding the physical origins of threshold switching and resistance drift phenomena is crucial to improve non-volatile phase-change memories. Even though both phenomena are often attributed to localized defect states in the band gap, the defect state density in amorphous phase-change materials has remained poorly studied. Starting from a brief introduction of the physics of phase-change materials this thesis summarizes the most important models behind electrical switching and resistance drift with the aim to discuss the role of localized defect states. The centerpiece of this thesis is the investigation of defects state densities in different amorphous phase-change materials and electrical switching chalcogenides. On the basis of Modulated Photo Current (MPC) Experiments and Photothermal Deflection Spectroscopy, a sophisticated band model for the disordered phase of the binary phase-change alloy GeTe has been developed. By this direct experimental approach the band-model for a

  9. Correlation between biological activity and electron transferring of bovine liver catalase: Osmolytes effects

    International Nuclear Information System (INIS)

    Tehrani, H. Sepasi; Moosavi-Movahedi, A.A.; Ghourchian, H.

    2013-01-01

    Highlights: • Proline increases ET in Bovine Liver Catalase (BLC) whereas histidine decreases it. • Proline also increased the biological activity, whereas histidine decreased it. • Electron transferring and biological activity for BLC are directly correlated. • Proline causes favorable ET for BLC shown by positive E 1/2 (E°′) and negative ΔG. • Histidine makes ET unfavorable for BLC, manifested by E 1/2 (E°′) 0. -- Abstract: Catalase is a crucial antioxidant enzyme that protects life against detrimental effects of H 2 O 2 by disproportionating it into water and molecular oxygen. Effect of proline as a compatible and histidine as a non compatible osmolyte on the electron transferring and midpoint potential of catalase has been investigated. Proline increases the midpoint potential (ΔE m > 0), therefore causing the ΔG ET to be less positive and making the electron transfer reaction more facile whereas histidine decreases the E m (ΔE m ET , thereby rendering the electron transfer reaction less efficient. These results indicate the inhibitory effect of histidine evident by a −37% decrease in the cathodic peak current compared to 16% increase in the case of proline indicative of activation. The insight paves the tedious way towards our ultimate goal of elucidating a correlation between biological activity and electron transferring

  10. Distorted wave calculations for electron loss process induced by bare ion impact on biological targets

    International Nuclear Information System (INIS)

    Monti, J.M.; Tachino, C.A.; Hanssen, J.; Fojón, O.A.; Galassi, M.E.; Champion, C.; Rivarola, R.D.

    2014-01-01

    Distorted wave models are employed to investigate the electron loss process induced by bare ions on biological targets. The two main reactions which contribute to this process, namely, the single electron ionization as well as the single electron capture are here studied. In order to further assess the validity of the theoretical descriptions used, the influence of particular mechanisms are studied, like dynamic screening for the case of electron ionization and energy deposition on the target by the impacting projectile for the electron capture one. Results are compared with existing experimental data. - Highlights: ► Distorted wave models are used to investigate ion-molecule collisions. ► Differential and total cross-sections for capture and ionization are evaluated. ► The influence of dynamic screening is determined. ► Capture reaction dominates the mean energy deposited by the projectile on the target

  11. Impacts of insufficient instructional materials on teaching biology: Higher education systems in focus

    Directory of Open Access Journals (Sweden)

    Sutuma Edessa

    2017-01-01

    Full Text Available Abstract The purpose of this study was to assess and determine impacts of insufficient instructional materials and ineffective lesson delivery methods on teaching in biology higher education. The participants of this study were 60 trainees who graduated in Bachelor of Sciences from eight public universities in majoring biology. Data for the study was collected while these trainees were attending the course of Biology Teaching Methods in the Post Graduate Diploma in Teaching, both in the regular and summer 2015/2016 training programs at Addis Ababa University. The study employs a mixed method design of both qualitative and quantitative data evaluations. Data was collected through classroom observations and interviews with the trainees. The findings indicated that insufficient instructional materials and ineffective teaching methods in higher education had negative impacts; that have affected the skills of performing biological tasks of graduates 71%. In the course of the Post Graduate Diploma in Teaching training, trainees were unsuccessful to conduct essential biological tasks expected from graduates of biology upon the completion of their undergraduate study program. The study was concluded with emphasis on the need to integrate theory and practice through using adequate instructional materials and proper teaching methods in the higher education biology teaching.

  12. Electron irradiation experiments in support of fusion materials development

    International Nuclear Information System (INIS)

    Gelles, D.S.; Ohnuki, S.; Takahashi, H.; Matsui, H.; Kohno, Y.

    1991-11-01

    Microstructural evolution in response to 1 MeV irradiation has been investigated for three simple ferritic alloys, pure beryllium, pure vanadium, and two simple vanadium alloys over a range of temperatures and doses. Microstructural evolution in Fe-3, -9, and -18Cr ferritic alloys is found to consist of crenulated, faulted a loops and circular, unfaulted a/2 loops at low temperatures, but with only unfaulted loops at high temperatures. The complex dislocation evolution is attributed to sigma phase precipifaults arising from chromium segregation to point defect sinks. Beryllium is found to be resistant to electron damage; the only effect observed was enhanced dislocation mobility. Pure vanadium, V-5Fe, and V-1Ni microstructural response was complicated by precipitation on heating to 400 degrees C and above, but dislocation evolution was investigated in the range of room temperature to 300 degrees C and at 600 degrees C. The three materials behaved similarly, except that pure vanadium showed more rapid dislocation evolution. This difference does not explain the enhanced swelling observed in vanadium alloys

  13. Electronic bandstructure of the ZnTe absorber material

    Energy Technology Data Exchange (ETDEWEB)

    Fritsch, Daniel [Leibniz Institute for Solid State and Materials Research IFW Dresden (Germany); Schmidt, Heidemarie [Forschungszentrum Dresden-Rossendorf, Dresden (Germany)

    2009-07-01

    Due to its large absorption coefficient, zinc telluride proved to be useful for the production of high-efficiency multi-junction solar cells. Nowadays ZnTe with a mixture of zincblende and wurtzite phases is fabricated by thin film growth techniques. The optical properties of both phases have been extensively studied by ab initio density functional methods. Here we focus on the question whether the effective electron and hole mass in ZnTe are small enough to meet the high-efficiency expectation of the ZnTe absorber material in solar cells and present direction dependent effective mass and Luttinger and Luttinger-like parameters of cubic and wurtzite ZnTe, respectively. Making use of the transferability of ionic model potential parameters and the experimentally known transition energies of different II-VI compounds ZnX (X=O,S,Se,Te), we obtained one single set of cationic model parameters for the Zn atom. The calculations have been performed by means of the empirical pseudopotential method using a simple empty core model potential.

  14. Use of a scanning electron microscope for examining radioactive materials

    International Nuclear Information System (INIS)

    Kauffmann, Yves; Prouve, Michel.

    1981-05-01

    The LAMA laboratory of the Grenoble Nuclear Research Center participates in studies carried out by research teams on fuels. Post-irradiation studies are performed on irradiated pins for research and development and safety programs. A scanning electron microscope was acquired for this purpose. This microscope had to fulfill certain criteria: it had to be sufficiently compact for it to be housed in a lead enclosure; it had to be capable of being adapted to operate with remote handling control. The modifications made to this microscope are briefly described together with the ancillary equipment of the cell. In parallel with these operations, an interconnection was realized enabling materials to be transferred between the various sampling and sample preparation cells and the microscope cell with a small transfer cask. After two years operating experience the microscope performance has been assessed satisfactory. The specific radioactivity of the samples themselves cannot be incriminated as the only cause of loss in resolution at magnifications greater than x 10,000 [fr

  15. Development and applications of photosensitive device systems to studies of biological and organic materials. Progress report

    International Nuclear Information System (INIS)

    1984-01-01

    The purpose was to develop and improve appropriate experimental techniques to the point where they could be applied to specific classes of biological problems. Progress is reported in the following areas: (1) area detectors; (2) x-ray diffraction studies of membranes; (3) electron transfer in loosely coupled systems; (4) bioluminescence and fluorescence; and (5) sonoluminescence

  16. Investigation of Electron Transfer-Based Photonic and Electro-Optic Materials and Devices

    Energy Technology Data Exchange (ETDEWEB)

    Bromenshenk, Jerry J; Abbott, Edwin H; Dickensheets, David; Donovan, Richard P; Hobbs, J D; Spangler, Lee; McGuirl, Michele A; Spangler, Charles; Rebane, Aleksander; Rosenburg, Edward; Schmidt, V H; Singel, David J

    2008-03-28

    Montana's state program began its sixth year in 2006. The project's research cluster focused on physical, chemical, and biological materials that exhibit unique electron-transfer properties. Our investigators have filed several patents and have also have established five spin-off businesses (3 MSU, 2 UM) and a research center (MT Tech). In addition, this project involved faculty and students at three campuses (MSU, UM, MT Tech) and has a number of under-represented students, including 10 women and 5 Native Americans. In 2006, there was an added emphasis on exporting seminars and speakers via the Internet from UM to Chief Dull Knife Community College, as well as work with the MT Department of Commerce to better educate our faculty regarding establishing small businesses, licensing and patent issues, and SBIR program opportunities.

  17. Materials Characterization at Utah State University: Facilities and Knowledge-base of Electronic Properties of Materials Applicable to Spacecraft Charging

    Science.gov (United States)

    Dennison, J. R.; Thomson, C. D.; Kite, J.; Zavyalov, V.; Corbridge, Jodie

    2004-01-01

    In an effort to improve the reliability and versatility of spacecraft charging models designed to assist spacecraft designers in accommodating and mitigating the harmful effects of charging on spacecraft, the NASA Space Environments and Effects (SEE) Program has funded development of facilities at Utah State University for the measurement of the electronic properties of both conducting and insulating spacecraft materials. We present here an overview of our instrumentation and capabilities, which are particularly well suited to study electron emission as related to spacecraft charging. These measurements include electron-induced secondary and backscattered yields, spectra, and angular resolved measurements as a function of incident energy, species and angle, plus investigations of ion-induced electron yields, photoelectron yields, sample charging and dielectric breakdown. Extensive surface science characterization capabilities are also available to fully characterize the samples in situ. Our measurements for a wide array of conducting and insulating spacecraft materials have been incorporated into the SEE Charge Collector Knowledge-base as a Database of Electronic Properties of Materials Applicable to Spacecraft Charging. This Database provides an extensive compilation of electronic properties, together with parameterization of these properties in a format that can be easily used with existing spacecraft charging engineering tools and with next generation plasma, charging, and radiation models. Tabulated properties in the Database include: electron-induced secondary electron yield, backscattered yield and emitted electron spectra; He, Ar and Xe ion-induced electron yields and emitted electron spectra; photoyield and solar emittance spectra; and materials characterization including reflectivity, dielectric constant, resistivity, arcing, optical microscopy images, scanning electron micrographs, scanning tunneling microscopy images, and Auger electron spectra. Further

  18. Evaluation of geologic materials to limit biological intrusion into low-level radioactive waste disposal sites

    International Nuclear Information System (INIS)

    Hakonson, T.E.

    1986-02-01

    This report describes the results of a three-year research program to evaluate the performance of selected soil and rock trench cap designs in limiting biological intrusion into simulated waste. The report is divided into three sections including a discussion of background material on biological interactions with waste site trench caps, a presentation of experimental data from field studies conducted at several scales, and a final section on the interpretation and limitations of the data including implications for the user

  19. [Clinical treatment adherence of health care workers and students exposed to potentially infectious biological material].

    Science.gov (United States)

    Almeida, Maria Cristina Mendes de; Canini, Silvia Rita Marin da Silva; Reis, Renata Karina; Toffano, Silmara Elaine Malaguti; Pereira, Fernanda Maria Vieira; Gir, Elucir

    2015-04-01

    To assess adherence to clinical appointments by health care workers (HCW) and students who suffered accidents with potentially infectious biological material. A retrospective cross-sectional study that assessed clinical records of accidents involving biological material between 2005 and 2010 in a specialized unit. A total of 461 individuals exposed to biological material were treated, of which 389 (84.4%) were HCWs and 72 (15.6%) students. Of the 461 exposed individuals, 307 (66.6%) attended a follow-up appointment. Individuals who had suffered an accident with a known source patient were 29 times more likely to show up to their scheduled follow-up appointments (OR: 29.98; CI95%: 16.09-55.83). The predictor in both univariate and multivariate analyses for adherence to clinical follow-up appointment was having a known source patient with nonreactive serology for the human immunodeficiency virus and/or hepatitis B and C.

  20. The Widespread Prevalence and Functional Significance of Silk-Like Structural Proteins in Metazoan Biological Materials.

    Directory of Open Access Journals (Sweden)

    Carmel McDougall

    Full Text Available In nature, numerous mechanisms have evolved by which organisms fabricate biological structures with an impressive array of physical characteristics. Some examples of metazoan biological materials include the highly elastic byssal threads by which bivalves attach themselves to rocks, biomineralized structures that form the skeletons of various animals, and spider silks that are renowned for their exceptional strength and elasticity. The remarkable properties of silks, which are perhaps the best studied biological materials, are the result of the highly repetitive, modular, and biased amino acid composition of the proteins that compose them. Interestingly, similar levels of modularity/repetitiveness and similar bias in amino acid compositions have been reported in proteins that are components of structural materials in other organisms, however the exact nature and extent of this similarity, and its functional and evolutionary relevance, is unknown. Here, we investigate this similarity and use sequence features common to silks and other known structural proteins to develop a bioinformatics-based method to identify similar proteins from large-scale transcriptome and whole-genome datasets. We show that a large number of proteins identified using this method have roles in biological material formation throughout the animal kingdom. Despite the similarity in sequence characteristics, most of the silk-like structural proteins (SLSPs identified in this study appear to have evolved independently and are restricted to a particular animal lineage. Although the exact function of many of these SLSPs is unknown, the apparent independent evolution of proteins with similar sequence characteristics in divergent lineages suggests that these features are important for the assembly of biological materials. The identification of these characteristics enable the generation of testable hypotheses regarding the mechanisms by which these proteins assemble and direct the

  1. OCCUPATIONAL ACCIDENTS WITH BIOLOGICAL MATERIALS IN CLINICAL ANALYSIS LABORATORY: CAUSES AND CONSEQUENCES

    Directory of Open Access Journals (Sweden)

    T. M. Azevedo

    2014-07-01

    Full Text Available Accidents involving biological material can cause diseases to the professional healthcare and also bring psychosocial effects. The aim of this study was to characterize the accidents occurring with biological material with professional of clinical laboratories of Sinop-MT. Data were collected by a questionnaire consisting of sociodemographic and health variables. 21 (87.5% of respondents stated that they never suffered any kind of accident. One of the injured workers reported that there was involvement in your emotional life. It is observed underreporting of occupational accidents by employees affected, making it difficult to increase research on the subject and actions about the problem.

  2. ATTENDING PROFESSIONALS VICTIMS OF ACCIDENT WITH BIOLOGICAL MATERIAL IN A TROPICAL DISEASES HOSPITAL

    OpenAIRE

    Lillian Kelly de Oliveira Lopes; Anaclara Ferreira Veiga Tipple; Sirlene Neves Damando; Cássia Silva Miranda; Ivete Vieira Gomes

    2006-01-01

    ABSTRACT: The occupational risk for the health´s workers is a subject discussed in the last decades. However, the professional accident involving biological material´s records in the health´s units don´t describe the real situation. The purpose of this article is to identify the number of attending of professional accident involving biological material and the source of the leading. The data were obtained by the professional accident´s handbooks in 2003. The hospital had 5768 appointments. Am...

  3. Determination of mercury concentration in biological materials by neutron activation analysis

    International Nuclear Information System (INIS)

    Munoz, L.; Gras, N.; Cortes, E.; Cassorla, V.

    1983-01-01

    The objective of this work was to obtain a confident analytical method for measuring the mercury concentration in biological materials. Destructive neutron activation analysis was used for this purpose and a radiochemical separation method was studied to isolate the mercury from its main interferences: sodium and phosphorus, because these elements in biological materials are in high concentrations. The method developed was based on the copper amalgamation under controlled conditions. Yield and reproductibility studies were performed using 203 Hg as radioactive tracer. Finally, food samples of regular consumption were analyzed and the results were compared with those recommended by FAO/WHO. (Author)

  4. Instrumental neutron activation analysis for the certification of biological reference materials

    International Nuclear Information System (INIS)

    Ambulkar, M.N.; Chutke, N.L.; Garg, A.N.

    1992-01-01

    A multielemental instrumental neutron activation analysis (INAA) method by short and long irradiation has been employed for the determination of 22 minor and trace constituents in two proposed Standard Reference Materials P-RBF and P-WBF from Institute of Radioecology and Applied Nuclear Techniques, Czechoslovakia. Also some biological standards such as Bowen's Kale, Cabbage leaves (Poland) including wheat and rice flour samples of local origin were analysed. It is suggested that INAA is an ideal method for the certification of reference materials of biological matrices. (author). 7 refs., 1 tab

  5. Noncovalent Intermolecular Interactions in Organic Electronic Materials: Implications for the Molecular Packing vs Electronic Properties of Acenes

    KAUST Repository

    Sutton, Christopher; Risko, Chad; Bredas, Jean-Luc

    2015-01-01

    Noncovalent intermolecular interactions, which can be tuned through the toolbox of synthetic chemistry, determine not only the molecular packing but also the resulting electronic, optical, and mechanical properties of materials derived from π

  6. Fresh biological reference materials. Use in inter laboratory studies and as CRMs

    International Nuclear Information System (INIS)

    De Boer, J.

    1999-01-01

    Biological reference materials were prepared and packed in tins and glass jars to be used in inter laboratory studies on chlorobiphenyls and organochlorine pesticides, and trace metals, respectively. The materials were homogenised, sterilised and packed as wet tissue, which is unique for the purpose of inter laboratory studies and offers the advantage of studying the extraction and destruction steps of the analytical methods. In addition to their use in inter laboratory studies, some materials have been prepared or are being prepared as certified reference material for chlorobiphenyl analysis. (author)

  7. Evaluation of Botanical Reference Materials for the Determination of Vanadium in Biological Samples

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Damsgaard, Else

    1982-01-01

    Three botanical reference materials prepared by the National Bureau of Standards have been studied by neutron activation analysis to evaluate their suitability with respect to the determination of vanadium in biological samples. Various decomposition methods were applied in connection with chemic....... A reference value of 1.15 mg/kg of this material is recommended, based on results from 3 different methods. All three materials are preferable to SRM 1571 Orchard Leaves, while Bowen's Kale remains the material of choice because of its lower concentration....

  8. Biological and environmental reference materials for trace elements, nuclides and organic microcontaminants

    International Nuclear Information System (INIS)

    Cortes Toro, E.; Parr, R.M.; Clements, S.A.

    1990-01-01

    This report has been produced from a database on analytical reference materials of biological and environmental origin, which is maintained at the International Atomic Energy Agency. It is an updated version of an earlier report, published in 1985, which focussed mainly on reference materials for trace elements. In the present version of the report, reference materials for trace elements still constitute the major part of the data; however, information is also now included on a number of other selected analytes of relevance to IAEA programmes, i.e. radionuclides, stable isotopes and organic microcontaminants. The database presently contains 2,694 analyte values for 117 analytes in 116 biological and 77 environmental (non-biological) reference materials produced by 20 different suppliers. Additional information on the cost of the material, the unit size supplied, (weight or volume), and the minimum weight of material recommended for analysis is also provided (if available to the authors). It is expected that this report will help analysts to select the reference material that matches as closely as possible, with respect to matrix type and concentrations of the analytes of interest, the ''real'' samples that are to be analysed. Refs, 12 tabs

  9. Applications of free-electron lasers to measurements of energy transfer in biopolymers and materials

    Science.gov (United States)

    Edwards, Glenn S.; Johnson, J. B.; Kozub, John A.; Tribble, Jerri A.; Wagner, Katrina

    1992-08-01

    Free-electron lasers (FELs) provide tunable, pulsed radiation in the infrared. Using the FEL as a pump beam, we are investigating the mechanisms for energy transfer between localized vibrational modes and between vibrational modes and lattice or phonon modes. Either a laser-Raman system or a Fourier transform infrared (FTIR) spectrometer will serve as the probe beam, with the attribute of placing the burden of detection on two conventional spectroscopic techniques that circumvent the limited response of infrared detectors. More specifically, the Raman effect inelastically shifts an exciting laser line, typically a visible frequency, by the energy of the vibrational mode; however, the shifted Raman lines also lie in the visible, allowing for detection with highly efficient visible detectors. With regards to FTIR spectroscopy, the multiplex advantage yields a distinct benefit for infrared detector response. Our group is investigating intramolecular and intermolecular energy transfer processes in both biopolymers and more traditional materials. For example, alkali halides contain a number of defect types that effectively transfer energy in an intermolecular process. Similarly, the functioning of biopolymers depends on efficient intramolecular energy transfer. Understanding these mechanisms will enhance our ability to modify biopolymers and materials with applications to biology, medecine, and materials science.

  10. Generalized Fokker-Planck theory for electron and photon transport in biological tissues: application to radiotherapy.

    Science.gov (United States)

    Olbrant, Edgar; Frank, Martin

    2010-12-01

    In this paper, we study a deterministic method for particle transport in biological tissues. The method is specifically developed for dose calculations in cancer therapy and for radiological imaging. Generalized Fokker-Planck (GFP) theory [Leakeas and Larsen, Nucl. Sci. Eng. 137 (2001), pp. 236-250] has been developed to improve the Fokker-Planck (FP) equation in cases where scattering is forward-peaked and where there is a sufficient amount of large-angle scattering. We compare grid-based numerical solutions to FP and GFP in realistic medical applications. First, electron dose calculations in heterogeneous parts of the human body are performed. Therefore, accurate electron scattering cross sections are included and their incorporation into our model is extensively described. Second, we solve GFP approximations of the radiative transport equation to investigate reflectance and transmittance of light in biological tissues. All results are compared with either Monte Carlo or discrete-ordinates transport solutions.

  11. Transmission/Scanning Transmission Electron Microscopy | Materials Science

    Science.gov (United States)

    crystallographic structure of a material. Amplitude-contrast images yield information about the chemistry and microstructure of a material and its defects. Phase-contrast imaging or high-resolution (HR) TEM imaging gives information about the microstructure of a material and its defects at an atomic resolution. With scanning

  12. Photo-induced regeneration of hormones by electron transfer processes: Potential biological and medical consequences

    Science.gov (United States)

    Getoff, Nikola; Hartmann, Johannes; Schittl, Heike; Gerschpacher, Marion; Quint, Ruth Maria

    2011-08-01

    Based on the previous results concerning electron transfer processes in biological substances, it was of interest to investigate if hormone transients resulting by e.g. electron emission can be regenerated. The presented results prove for the first time that the hormone transients originating by the electron emission process can be successfully regenerated by the transfer of electrons from a potent electron donor, such as vitamin C (VitC). Investigations were performed using progesterone (PRG), testosterone (TES) and estrone (E1) as representatives of hormones. By irradiation with monochromatic UV light (λ=254 nm) in a media of 40% water and 60% ethanol, the degradation as well as the regeneration of the hormones was studied with each hormone individually and in the mixture with VitC as a function of the absorbed UV dose, using HPLC. Calculated from the obtained initial yields, the determined regeneration of PRG amounted to 52.7%, for TES to 58.6% and for E1 to 90.9%. The consumption of VitC was determined in the same way. The reported results concerning the regeneration of hormones by the transfer of electrons from an electron donor offer a new, promising method for the therapy with hormones. As a consequence of the regeneration of hormones, a decreased formation of carcinogenic metabolites is expected.

  13. Photo-induced regeneration of hormones by electron transfer processes: Potential biological and medical consequences

    Energy Technology Data Exchange (ETDEWEB)

    Getoff, Nikola, E-mail: nikola.getoff@univie.ac.a [Section of Radiation Biology, Faculty of Life Sciences, University of Vienna, A-1090 Vienna (Austria); Hartmann, Johannes [Department of Gynecologic Endocrinology and Reproduction, Medical University of Vienna, A-1090 Vienna (Austria); Schittl, Heike [Section of Radiation Biology, Faculty of Life Sciences, University of Vienna, A-1090 Vienna (Austria); Gerschpacher, Marion [Department of Gynecologic Endocrinology and Reproduction, Medical University of Vienna, A-1090 Vienna (Austria); Quint, Ruth Maria [Section of Radiation Biology, Faculty of Life Sciences, University of Vienna, A-1090 Vienna (Austria)

    2011-08-15

    Based on the previous results concerning electron transfer processes in biological substances, it was of interest to investigate if hormone transients resulting by e.g. electron emission can be regenerated. The presented results prove for the first time that the hormone transients originating by the electron emission process can be successfully regenerated by the transfer of electrons from a potent electron donor, such as vitamin C (VitC). Investigations were performed using progesterone (PRG), testosterone (TES) and estrone (E1) as representatives of hormones. By irradiation with monochromatic UV light ({lambda}=254 nm) in a media of 40% water and 60% ethanol, the degradation as well as the regeneration of the hormones was studied with each hormone individually and in the mixture with VitC as a function of the absorbed UV dose, using HPLC. Calculated from the obtained initial yields, the determined regeneration of PRG amounted to 52.7%, for TES to 58.6% and for E1 to 90.9%. The consumption of VitC was determined in the same way. The reported results concerning the regeneration of hormones by the transfer of electrons from an electron donor offer a new, promising method for the therapy with hormones. As a consequence of the regeneration of hormones, a decreased formation of carcinogenic metabolites is expected.

  14. Photo-induced regeneration of hormones by electron transfer processes: Potential biological and medical consequences

    International Nuclear Information System (INIS)

    Getoff, Nikola; Hartmann, Johannes; Schittl, Heike; Gerschpacher, Marion; Quint, Ruth Maria

    2011-01-01

    Based on the previous results concerning electron transfer processes in biological substances, it was of interest to investigate if hormone transients resulting by e.g. electron emission can be regenerated. The presented results prove for the first time that the hormone transients originating by the electron emission process can be successfully regenerated by the transfer of electrons from a potent electron donor, such as vitamin C (VitC). Investigations were performed using progesterone (PRG), testosterone (TES) and estrone (E1) as representatives of hormones. By irradiation with monochromatic UV light (λ=254 nm) in a media of 40% water and 60% ethanol, the degradation as well as the regeneration of the hormones was studied with each hormone individually and in the mixture with VitC as a function of the absorbed UV dose, using HPLC. Calculated from the obtained initial yields, the determined regeneration of PRG amounted to 52.7%, for TES to 58.6% and for E1 to 90.9%. The consumption of VitC was determined in the same way. The reported results concerning the regeneration of hormones by the transfer of electrons from an electron donor offer a new, promising method for the therapy with hormones. As a consequence of the regeneration of hormones, a decreased formation of carcinogenic metabolites is expected.

  15. Instrumental neutron activation analysis of phosphorus in biological materials by Bremsstrahlung measurement

    International Nuclear Information System (INIS)

    Bajo, S.; Wyttenbach, A.

    1986-12-01

    The determination of phosphorus in biological materials by instrumental neutron activation via the reaction 31 P (n,γ) 32 P is described. The Bremsstrahlung produced by 32 P is measured in a well-type NaI(Tl) detector. The samples are measured within the polyethylene irradiation container with no changes between irradiation and measurement. The sources of error were studied and the proposed method was applied to the determination of phosphorus in ten internationally certified materials. (author)

  16. Current studies of biological materials using instrumental and radiochemical neutron activation analysis

    International Nuclear Information System (INIS)

    Fardy, J.J.; McOrist, G.D.; Farrar, Y.J.

    1985-01-01

    Instrumental neutron activation analysis still remains the preferred option when analysing the trace element distribution in a wide rage of materials by neutron activation analysis. However, when lower limits of detection are required or major interferences reduce the effectiveness of this technique, radiochemical neutron activation analysis is applied. This paper examines the current use of both methods and the development of rapid radiochemical techniques for analysis of the biological materials, hair, cow's milk, human's milk, milk powder, blood and blood serum

  17. Integrating phenotypic data from electronic patient records with molecular level systems biology

    DEFF Research Database (Denmark)

    Brunak, Søren

    2011-01-01

    Electronic patient records remain a rather unexplored, but potentially rich data source for discovering correlations between diseases. We describe a general approach for gathering phenotypic descriptions of patients from medical records in a systematic and non-cohort dependent manner. By extracti...... Classification of Disease ontology and is therefore in principle language independent. As a use case we show how records from a Danish psychiatric hospital lead to the identification of disease correlations, which subsequently are mapped to systems biology frameworks....

  18. Direct Electron Transfer of Enzymes in a Biologically Assembled Conductive Nanomesh Enzyme Platform.

    Science.gov (United States)

    Lee, Seung-Woo; Lee, Ki-Young; Song, Yong-Won; Choi, Won Kook; Chang, Joonyeon; Yi, Hyunjung

    2016-02-24

    Nondestructive assembly of a nanostructured enzyme platform is developed in combination of the specific biomolecular attraction and electrostatic coupling for highly efficient direct electron transfer (DET) of enzymes with unprecedented applicability and versatility. The biologically assembled conductive nanomesh enzyme platform enables DET-based flexible integrated biosensors and DET of eight different enzyme with various catalytic activities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Graphene as a transparent conductive support for studying biological molecules by transmission electron microscopy

    International Nuclear Information System (INIS)

    Nair, R. R.; Anissimova, S.; Novoselov, K. S.; Blake, P.; Blake, J. R.; Geim, A. K.; Zan, R.; Bangert, U.; Golovanov, A. P.; Morozov, S. V.; Latychevskaia, T.

    2010-01-01

    We demonstrate the application of graphene as a support for imaging individual biological molecules in transmission electron microscope (TEM). A simple procedure to produce free-standing graphene membranes has been designed. Such membranes are extremely robust and can support practically any submicrometer object. Tobacco mosaic virus has been deposited on graphene samples and observed in a TEM. High contrast has been achieved even though no staining has been applied.

  20. RGB color coded images in scanning electron microscopy of biological surfaces

    Czech Academy of Sciences Publication Activity Database

    Kofroňová, Olga; Benada, Oldřich

    2017-01-01

    Roč. 61, č. 3 (2017), s. 349-352 ISSN 0001-723X R&D Projects: GA MŠk(CZ) LO1509; GA ČR(CZ) GA16-20229S Institutional support: RVO:61388971 Keywords : Biological surfaces * Color image s * Scanning electron microscopy Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 0.673, year: 2016

  1. Topological insulator materials and nanostructures for future electronics, spintronics and energy conversion

    International Nuclear Information System (INIS)

    Kantser, Valeriu

    2011-01-01

    Two fundamental electrons attributes in materials and nanostructures - charge and spin - determine their electronic properties. The processing of information in conventional electronic devices is based only on the charge of the electrons. Spin electronics, or spintronics, uses the spin of electrons, as well as their charge, to process information. Metals, semiconductors and insulators are the basic materials that constitute the components of electronic devices, and these have been transforming all aspects of society for over a century. In contrast, magnetic metals, half-metals, magnetic semiconductors, dilute magnetic semiconductors and magnetic insulators are the materials that will form the basis for spintronic devices. Materials with topological band structure attributes and having a zero-energy band gap surface states are a special class of these materials that exhibit some fascinating and superior electronic properties compared to conventional materials allowing to combine both charge and spin functionalities. This article reviews a range of topological insulator materials and nanostructures with tunable surface states, focusing on nanolayered and nanowire like structures. These materials and nanostructures all have intriguing physical properties and numerous potential practical applications in spintronics, electronics, optics and sensors.

  2. Invited review liquid crystal models of biological materials and silk spinning.

    Science.gov (United States)

    Rey, Alejandro D; Herrera-Valencia, Edtson E

    2012-06-01

    A review of thermodynamic, materials science, and rheological liquid crystal models is presented and applied to a wide range of biological liquid crystals, including helicoidal plywoods, biopolymer solutions, and in vivo liquid crystals. The distinguishing characteristics of liquid crystals (self-assembly, packing, defects, functionalities, processability) are discussed in relation to biological materials and the strong correspondence between different synthetic and biological materials is established. Biological polymer processing based on liquid crystalline precursors includes viscoelastic flow to form and shape fibers. Viscoelastic models for nematic and chiral nematics are reviewed and discussed in terms of key parameters that facilitate understanding and quantitative information from optical textures and rheometers. It is shown that viscoelastic modeling the silk spinning process using liquid crystal theories sheds light on textural transitions in the duct of spiders and silk worms as well as on tactoidal drops and interfacial structures. The range and consistency of the predictions demonstrates that the use of mesoscopic liquid crystal models is another tool to develop the science and biomimetic applications of mesogenic biological soft matter. Copyright © 2011 Wiley Periodicals, Inc.

  3. Analysis of 10 years of accidents with biological material among the nursing staff

    Directory of Open Access Journals (Sweden)

    Dayane Xavier de Barros

    2016-06-01

    Full Text Available The objectives of the present study were: to identify the profile of accidents with biological material among nursing professionals treated in a reference service; to characterize pre-exposure conducts and to analyze factors associated with percutaneous exposure. An epidemiological, retrospective and analytical study was conducted in records of accidents involving biological material from 2000 to 2010. The number of accidents with the nursing staff was 2,569, representing 44.6% of the total records. There was a prevalence of percutaneous exposure cases involving needles with lumen and blood in upper limbs among female nursing technicians. Being female and working outside the city where the service is located increased about twice the chances of suffering percutaneous accidents. The data found strengthen the importance of biological risk in the nursing practice and point to the fact that workers have to move between cities to be treated when the accident is considered serious, such as the case of percutaneous accidents.

  4. Determination of the dynamical behaviour of biological materials during impact using a pendulum device

    Science.gov (United States)

    Van Zeebroeck, M.; Tijskens, E.; Van Liedekerke, P.; Deli, V.; De Baerdemaeker, J.; Ramon, H.

    2003-09-01

    A pendulum device has been developed to measure contact force, displacement and displacement rate of an impactor during its impact on the sample. Displacement, classically measured by double integration of an accelerometer, was determined in an alternative way using a more accurate incremental optical encoder. The parameters of the Kuwabara-Kono contact force model for impact of spheres have been estimated using an optimization method, taking the experimentally measured displacement, displacement rate and contact force into account. The accuracy of the method was verified using a rubber ball. Contact force parameters for the Kuwabara-Kono model have been estimated with success for three biological materials, i.e., apples, tomatoes and potatoes. The variability in the parameter estimations for the biological materials was quite high and can be explained by geometric differences (radius of curvature) and by biological variation of mechanical tissue properties.

  5. Measuring the complex permittivity tensor of uniaxial biological materials with coplanar waveguide transmission line

    Science.gov (United States)

    A simple and accurate technique is described for measuring the uniaxial permittivity tensor of biological materials with a coplanar waveguide transmission-line configuration. Permittivity tensor results are presented for several chicken and beef fresh meat samples at 2.45 GHz....

  6. Simultaneous Determination of Arsenic, Manganese, and Selenium in Biological Materials by Neutron-Activation Analysis

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Damsgaard, Else

    1973-01-01

    A new method was developed for the simultaneous determination of arsenic, manganese, and selenium in biological material by thermal-neutron activation analysis. The use of 81 mSe as indicator for selenium permitted a reduction of activation time to 1 hr for a 1 g sample, and the possibility of loss...

  7. Raman imaging from microscopy to macroscopy: Quality and safety control of biological materials

    Science.gov (United States)

    Raman imaging can analyze biological materials by generating detailed chemical images. Over the last decade, tremendous advancements in Raman imaging and data analysis techniques have overcome problems such as long data acquisition and analysis times and poor sensitivity. This review article introdu...

  8. Potential interferences inherent in neutron-activation analysis of trace elements in biological materials

    International Nuclear Information System (INIS)

    Cornells, R.; Hoste, J.; Versieck, J.

    1982-01-01

    A comprehensive review is given of how neutron-activation analysis for trace elements in biological matrices can be jeopardized by radiation damage, by the impurities present in the packing material or by nuclear interferences of major elements. Systematic errors during the counting process and the quantitative interpretation of the γ-ray spectra should not be disregarded. (author)

  9. Neutron-Activation Analysis of Biological Material with High Radiation Levels

    Energy Technology Data Exchange (ETDEWEB)

    Samsahl, K

    1966-09-15

    A method has been developed for the chemical separation and subsequent gamma-spectrometric analysis of the alkali metals, the alkaline earths, the rare earths, chromium, hafnium, lanthanum, manganese, phosphorus, scandium and silver in neutron-activated biological material. The separation steps, being fully automatic, are based on a combination of ion-exchange and partition chromatography and require 40 min.

  10. An independent accurate reference method for the determination of chromium in biological materials

    NARCIS (Netherlands)

    Lagerwaard, A.; Woittiez, J.R.W.; de Goeij, J.J.M.

    1994-01-01

    A method for the determination of Cr in biological materials with high accuracy is reported for use as an independent reference method. It is based on radiochemical neutron activation analysis (RNAA) in combination with an individual yield determination based on the online yield principle. A

  11. Selenium determination in biological material by atomic absorption spectrophotometry in graphite furnace and using vapor generation

    International Nuclear Information System (INIS)

    Carvalho Vidal, M. de F. de.

    1984-01-01

    The applicability of the atomic absorption spectrophotometry to the determination of selenium in biological material using vapor generation and electrothermal atomization in the graphite furnace was investigated. Instrumental parameters and the analytical conditions of the methods were studied. Decomposition methods for the samples were tested, and the combustion in the Wickbold apparatus was chosen. (author) [pt

  12. Neutron-Activation Analysis of Biological Material with High Radiation Levels

    International Nuclear Information System (INIS)

    Samsahl, K.

    1966-09-01

    A method has been developed for the chemical separation and subsequent gamma-spectrometric analysis of the alkali metals, the alkaline earths, the rare earths, chromium, hafnium, lanthanum, manganese, phosphorus, scandium and silver in neutron-activated biological material. The separation steps, being fully automatic, are based on a combination of ion-exchange and partition chromatography and require 40 min

  13. Materiality, Symbolicity, and the Rhetoric of Order: "Dialectical Biologism" as Motive in Burke.

    Science.gov (United States)

    Engnell, Richard A.

    1998-01-01

    Considers how the work of Kenneth Burke has recently been critiqued for its lack of attention to the role of non-symbolic motivation in rhetoric. Describes Burke's contributions as a "dialectical biologism" that sets forth a system of five symbolic/material dialectics that undergird all rhetorical appeal. Suggests that the most effective…

  14. The use of reference materials in the elemental analysis of biological samples

    International Nuclear Information System (INIS)

    Bowen, H.J.M.

    1975-01-01

    Reference materials (RMs) are useful to compare the accuracy and precision of laboratories and techniques. The desirable properties of biological reference materials are listed, and the problems of production, homogenization and storage described. At present there are only 10 biological RMs available compared with 213 geological and 520 metallurgical RMs. There is a need for more biological RMs including special materials for microprobe analysis and for in vivo activation analysis. A study of 650 mean values for elements in RM Kale, analysed by many laboratories, leads to the following conclusions. 61% of the values lie within +-10% of the best mean, and 80% lie within +-20% of the best mean. Atomic absorption spectrometry gives results that are 5-30% high for seven elements, while intrumental neutron activation analysis gives low and imprecise results for K. Other techniques with poor interlaboratory precision include neutron activation for Mg, polarography for Zn and arc-spectrometry for many elements. More than half the values for elements in Kale were obtained by neutron activation, confirming the importance of this technique and the need for RMs. As a rough estimate, 6 x 10 9 elemental analyses of biological materials are carried out each year, mostly by medical, agricultural and food scientists. It seems likely that a substantial percentage of these are inaccurate, a situation that might be improved by quality control using standard RMs. (author)

  15. Adhesives technology for electronic applications materials, processing, reliability

    CERN Document Server

    Licari, James J

    2011-01-01

    Adhesives are widely used in the manufacture and assembly of electronic circuits and products. Generally, electronics design engineers and manufacturing engineers are not well versed in adhesives, while adhesion chemists have a limited knowledge of electronics. This book bridges these knowledge gaps and is useful to both groups. The book includes chapters covering types of adhesive, the chemistry on which they are based, and their properties, applications, processes, specifications, and reliability. Coverage of toxicity, environmental impacts and the regulatory framework make this book par

  16. Writing an Electronic Astronomy Book with Interactive Curricular Material

    Science.gov (United States)

    Thompson, Kristen L.; Belloni, Mario; Christian, Wolfgang

    2015-01-01

    With the rise of tablets, the past few years have seen an increase in the demand for quality electronic textbooks. Unfortunately, most of the current offerings do not exploit the accessibility and interactivity that electronic books can deliver. In this poster, we discuss how we are merging our curriculum development projects (Physlets, Easy Java/JavaScript Simulations, and Open Source Physics) with the EPUB electronic book format to develop an interactive textbook for use in a one-semester introductory astronomy course. The book, Astronomy: An Interactive Introduction, combines the narrative, equations, and images of a traditional astronomy text with new JavaScript simulations.

  17. Dependence of electron inelastic mean free paths on electron energy and materials at low energy region, 1

    International Nuclear Information System (INIS)

    Tanuma, Shigeo; Powell, C.J.; Penn, D.R.

    1990-01-01

    We have proposed a general formula of electron inelastic mean free path (IMFP) to describe the calculated IMFPs over the 50-2000 eV energy range based on the Inokuti's modified Bethe formula for the inelastic scattering cross section. The IMFPs for 50-2000 eV electrons in 27 elements were calculated using Penn's algorithm. The IMFP dependence on electron energy in the range 50-200 eV varies considerably from material to material. These variations are associated with substantial differences in the electron energy-loss functions amongst the material. We also found that the modified Bethe formula by Inokuti could be fitted to the calculated IMFPs in the range 50-2000 eV within 3% relative error. (author)

  18. Bifunctional electroluminescent and photovoltaic devices using bathocuproine as electron-transporting material and an electron acceptor

    International Nuclear Information System (INIS)

    Chen, L.L.; Li, W.L.; Li, M.T.; Chu, B.

    2007-01-01

    Electroluminescence (EL) devices, using 4, 4',4''-tris (2-methylphenyl- phenylamino) triphenylamine (m-MTDATA) as hole-transporting material and bathocuproine (BCP) as an electron-transporting material, were fabricated, which emitted bright green light peaked at 520 nm instead of the emission of m-MTDATA or BCP. It was attributed to the exciplex formation and emission at the interface of m-MTDATA and BCP. EL performance was significantly enhanced by a thin mixed layer (5 nm) of m-MTDATA and BCP inserted between the two organic layers of the original m-MTDATA/BCP bilayer device. The trilayer device showed maximum luminance of 1,205 cd/m 2 at 8 V. At a luminance of 100 cd/m 2 , the power efficiency is 1.64 cd/A. Commission International De L'Eclairoge (CIE) color coordinates of the output spectrum of the devices at 8 V are x=0.244 and y=0.464. These devices also showed photovoltaic (PV) properties, which were sensitive to UV light. The PV diode exhibits high open-circuit voltage (V oc ) of 2.10 V under illumination of 365 nm UV light with 2 mW/cm 2 . And the short-circuit current (I sc ) of 92.5x10 -6 A/cm 2 , fill factor (FF) of 0.30 and power conversion efficiency (η e ) of 2.91% are respectively achieved. It is considered that strong exciplex emission in an EL device is a good indicator of efficient charge transfer at the organic interface, which is a basic requirement for good PV performance. Both the bilayer and trilayer devices showed EL and PV properties, suggesting their potential use as multifunction devices

  19. Bifunctional electroluminescent and photovoltaic devices using bathocuproine as electron-transporting material and an electron acceptor

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.L. [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China); Graduate School of the Chinese Academy of Sciences, Beijing, 100039 (China); Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, 130024 (China); Li, W.L. [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China)]. E-mail: wllioel@yahoo.com.cn; Li, M.T. [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China); Graduate School of the Chinese Academy of Sciences, Beijing, 100039 (China); Chu, B. [Key Laboratory of the Excited States Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China)

    2007-01-15

    Electroluminescence (EL) devices, using 4, 4',4''-tris (2-methylphenyl- phenylamino) triphenylamine (m-MTDATA) as hole-transporting material and bathocuproine (BCP) as an electron-transporting material, were fabricated, which emitted bright green light peaked at 520 nm instead of the emission of m-MTDATA or BCP. It was attributed to the exciplex formation and emission at the interface of m-MTDATA and BCP. EL performance was significantly enhanced by a thin mixed layer (5 nm) of m-MTDATA and BCP inserted between the two organic layers of the original m-MTDATA/BCP bilayer device. The trilayer device showed maximum luminance of 1,205 cd/m{sup 2} at 8 V. At a luminance of 100 cd/m{sup 2}, the power efficiency is 1.64 cd/A. Commission International De L'Eclairoge (CIE) color coordinates of the output spectrum of the devices at 8 V are x=0.244 and y=0.464. These devices also showed photovoltaic (PV) properties, which were sensitive to UV light. The PV diode exhibits high open-circuit voltage (V {sub oc}) of 2.10 V under illumination of 365 nm UV light with 2 mW/cm{sup 2}. And the short-circuit current (I {sub sc}) of 92.5x10{sup -6} A/cm{sup 2}, fill factor (FF) of 0.30 and power conversion efficiency ({eta} {sub e}) of 2.91% are respectively achieved. It is considered that strong exciplex emission in an EL device is a good indicator of efficient charge transfer at the organic interface, which is a basic requirement for good PV performance. Both the bilayer and trilayer devices showed EL and PV properties, suggesting their potential use as multifunction devices.

  20. Metal-like transport in proteins: A new paradigm for biological electron transfer

    Science.gov (United States)

    Malvankar, Nikhil; Vargas, Madeline; Tuominen, Mark; Lovley, Derek

    2012-02-01

    Electron flow in biologically proteins generally occurs via tunneling or hopping and the possibility of electron delocalization has long been discounted. Here we report metal-like transport in protein nanofilaments, pili, of bacteria Geobacter sulfurreducens that challenges this long-standing belief [1]. Pili exhibit conductivities comparable to synthetic organic metallic nanostructures. The temperature, magnetic field and gate-voltage dependence of pili conductivity is akin to that of quasi-1D disordered metals, suggesting a metal-insulator transition. Magnetoresistance (MR) data provide evidence for quantum interference and weak localization at room temperature, as well as a temperature and field-induced crossover from negative to positive MR. Furthermore, pili can be doped with protons. Structural studies suggest the possibility of molecular pi stacking in pili, causing electron delocalization. Reducing the disorder increases the metallic nature of pili. These electronically functional proteins are a new class of electrically conductive biological proteins that can be used to generate future generation of inexpensive and environmentally-sustainable nanomaterials and nanolectronic devices such as transistors and supercapacitors. [1] Malvankar et al. Nature Nanotechnology, 6, 573-579 (2011)

  1. Polymeric and Molecular Materials for Advanced Organic Electronics

    Science.gov (United States)

    2014-10-20

    we were able to substantially lower the HOMOs while preserving excellent TFT hole transport, and investigated their use in bulk- hetero - junction ...metal oxide semiconductors, which are prepared by a low-temperature “combustion synthesis” route invented at NU under AFOSR support and published...98) v Prescribed by ANSI Std. Z39.18 Introduction. CMOS, p/n- Junction Devices, and Flexible Electronics Flexible/printed electronics is a

  2. Secondary Electron Emission Materials for Transmission Dynodes in Novel Photomultipliers: A Review

    Directory of Open Access Journals (Sweden)

    Shu Xia Tao

    2016-12-01

    Full Text Available Secondary electron emission materials are reviewed with the aim of providing guidelines for the future development of novel transmission dynodes. Materials with reflection secondary electron yield higher than three and transmission secondary electron yield higher than one are tabulated for easy reference. Generations of transmission dynodes are listed in the order of the invention time with a special focus on the most recent atomic-layer-deposition synthesized transmission dynodes. Based on the knowledge gained from the survey of secondary election emission materials with high secondary electron yield, an outlook of possible improvements upon the state-of-the-art transmission dynodes is provided.

  3. How accelerated biological aging can affect solar reflective polymeric based building materials

    Science.gov (United States)

    Ferrari, C.; Santunione, G.; Libbra, A.; Muscio, A.; Sgarbi, E.

    2017-11-01

    Among the main issues concerning building materials, in particular outdoor ones, one can identify the colonization by microorganisms referred to as biological aggression. This can affect not only the aesthetical aspect but also the thermal performance of solar reflective materials. In order to improve the reliability of tests aimed to assess the resistance to biological aggression and contextually reduce the test duration, an accelerated test method has been developed. It is based on a lab reproducible setup where specific and controlled environmental and boundary conditions are imposed to accelerate as much as possible biological growth on building materials. Due to their widespread use, polymeric materials have been selected for the present analysis, in the aim of reaching an advanced bio-aged level in a relatively short time (8 weeks or less) and at the same time comparatively evaluate different materials under a given set of ageing conditions. Surface properties before, during and after ageing have been investigated by surface, microstructural and chemical analyses, as well as by examination of time progressive images to assess bacterial and algal growth rate.

  4. Electron work function-a promising guiding parameter for material design.

    Science.gov (United States)

    Lu, Hao; Liu, Ziran; Yan, Xianguo; Li, Dongyang; Parent, Leo; Tian, Harry

    2016-04-14

    Using nickel added X70 steel as a sample material, we demonstrate that electron work function (EWF), which largely reflects the electron behavior of materials, could be used as a guide parameter for material modification or design. Adding Ni having a higher electron work function to X70 steel brings more "free" electrons to the steel, leading to increased overall work function, accompanied with enhanced e(-)-nuclei interactions or higher atomic bond strength. Young's modulus and hardness increase correspondingly. However, the free electron density and work function decrease as the Ni content is continuously increased, accompanied with the formation of a second phase, FeNi3, which is softer with a lower work function. The decrease in the overall work function corresponds to deterioration of the mechanical strength of the steel. It is expected that EWF, a simple but fundamental parameter, may lead to new methodologies or supplementary approaches for metallic materials design or tailoring on a feasible electronic base.

  5. Electron Transfer in Donor-Bridge-Acceptor Systems and Derived Materials

    NARCIS (Netherlands)

    Oosterbaan, W.D.

    2002-01-01

    Some aspects of photoinduced electron transfer (ET) in (electron donor)-bridge-(electron acceptor) compounds (D-B-A) and derived materials are investigated. Aim I is to determine how and to which extent non-conjugated double bonds in an otherwise saturated hydrocarbon bridge affect the rate of

  6. Electron-beam-irradiation-induced crystallization of amorphous solid phase change materials

    Science.gov (United States)

    Zhou, Dong; Wu, Liangcai; Wen, Lin; Ma, Liya; Zhang, Xingyao; Li, Yudong; Guo, Qi; Song, Zhitang

    2018-04-01

    The electron-beam-irradiation-induced crystallization of phase change materials in a nano sized area was studied by in situ transmission electron microscopy and selected area electron diffraction. Amorphous phase change materials changed to a polycrystalline state after being irradiated with a 200 kV electron beam for a long time. The results indicate that the crystallization temperature strongly depends on the difference in the heteronuclear bond enthalpy of the phase change materials. The selected area electron diffraction patterns reveal that Ge2Sb2Te5 is a nucleation-dominated material, when Si2Sb2Te3 and Ti0.5Sb2Te3 are growth-dominated materials.

  7. "Green" electronics: biodegradable and biocompatible materials and devices for sustainable future.

    Science.gov (United States)

    Irimia-Vladu, Mihai

    2014-01-21

    "Green" electronics represents not only a novel scientific term but also an emerging area of research aimed at identifying compounds of natural origin and establishing economically efficient routes for the production of synthetic materials that have applicability in environmentally safe (biodegradable) and/or biocompatible devices. The ultimate goal of this research is to create paths for the production of human- and environmentally friendly electronics in general and the integration of such electronic circuits with living tissue in particular. Researching into the emerging class of "green" electronics may help fulfill not only the original promise of organic electronics that is to deliver low-cost and energy efficient materials and devices but also achieve unimaginable functionalities for electronics, for example benign integration into life and environment. This Review will highlight recent research advancements in this emerging group of materials and their integration in unconventional organic electronic devices.

  8. Thermal interface material characterization for cryogenic electronic packaging solutions

    Science.gov (United States)

    Dillon, A.; McCusker, K.; Van Dyke, J.; Isler, B.; Christiansen, M.

    2017-12-01

    As applications of superconducting logic technologies continue to grow, the need for efficient and reliable cryogenic packaging becomes crucial to development and testing. A trade study of materials was done to develop a practical understanding of the properties of interface materials around 4 K. While literature exists for varying interface tests, discrepancies are found in the reported performance of different materials and in the ranges of applied force in which they are optimal. In considering applications extending from top cooling a silicon chip to clamping a heat sink, a range of forces from approximately 44 N to approximately 445 N was chosen for testing different interface materials. For each range of forces a single material was identified to optimize the thermal conductance of the joint. Of the tested interfaces, indium foil clamped at approximately 445 N showed the highest thermal conductance. Results are presented from these characterizations and useful methodologies for efficient testing are defined.

  9. Chemical preparation of biological materials for accurate chromium determination by isotope dilution mass spectrometry

    International Nuclear Information System (INIS)

    Dunstan, L.P.; Garner, E.L.

    1977-01-01

    The current interest in trace elements in biological materials has created a need for accurate methods of analysis. The source of discrepancies and variations in chromium concentration determinations is often traceable to inadequate methods of sample preparation. Any method of Cr analysis that requires acid digestion of a biological matrix must take into consideration the existence or formation of a volatile Cr component. In addition, because Cr is often present at concentrations less than 1 μg/g, the analytical blank becomes a potential source of error. Chemical procedures have been developed for the digestion of the biological matrix and the separation of Cr without either large analytical blanks or significant losses by volatilization. These procedures have been used for the analysis of NBS Standard Reference Material (SRM) 1569 Brewers Yeast; SRM 1577 Bovine Liver; SRM 1570 Spinach and other biological materials including human hair and nails. At this time, samples containing 1 μg of Cr can be determined with an estimated accuracy of 2 percent

  10. Evaluation of a fungal collection as certified reference material producer and as a biological resource center

    Directory of Open Access Journals (Sweden)

    Tatiana Forti

    2016-06-01

    Full Text Available Abstract Considering the absence of standards for culture collections and more specifically for biological resource centers in the world, in addition to the absence of certified biological material in Brazil, this study aimed to evaluate a Fungal Collection from Fiocruz, as a producer of certified reference material and as Biological Resource Center (BRC. For this evaluation, a checklist based on the requirements of ABNT ISO GUIA34:2012 correlated with the ABNT NBR ISO/IEC17025:2005, was designed and applied. Complementing the implementation of the checklist, an internal audit was performed. An evaluation of this Collection as a BRC was also conducted following the requirements of the NIT-DICLA-061, the Brazilian internal standard from Inmetro, based on ABNT NBR ISO/IEC 17025:2005, ABNT ISO GUIA 34:2012 and OECD Best Practice Guidelines for BRCs. This was the first time that the NIT DICLA-061 was applied in a culture collection during an internal audit. The assessments enabled the proposal for the adequacy of this Collection to assure the implementation of the management system for their future accreditation by Inmetro as a certified reference material producer as well as its future accreditation as a Biological Resource Center according to the NIT-DICLA-061.

  11. Evaluation of a fungal collection as certified reference material producer and as a biological resource center.

    Science.gov (United States)

    Forti, Tatiana; Souto, Aline da S S; do Nascimento, Carlos Roberto S; Nishikawa, Marilia M; Hubner, Marise T W; Sabagh, Fernanda P; Temporal, Rosane Maria; Rodrigues, Janaína M; da Silva, Manuela

    2016-01-01

    Considering the absence of standards for culture collections and more specifically for biological resource centers in the world, in addition to the absence of certified biological material in Brazil, this study aimed to evaluate a Fungal Collection from Fiocruz, as a producer of certified reference material and as Biological Resource Center (BRC). For this evaluation, a checklist based on the requirements of ABNT ISO GUIA34:2012 correlated with the ABNT NBR ISO/IEC17025:2005, was designed and applied. Complementing the implementation of the checklist, an internal audit was performed. An evaluation of this Collection as a BRC was also conducted following the requirements of the NIT-DICLA-061, the Brazilian internal standard from Inmetro, based on ABNT NBR ISO/IEC 17025:2005, ABNT ISO GUIA 34:2012 and OECD Best Practice Guidelines for BRCs. This was the first time that the NIT DICLA-061 was applied in a culture collection during an internal audit. The assessments enabled the proposal for the adequacy of this Collection to assure the implementation of the management system for their future accreditation by Inmetro as a certified reference material producer as well as its future accreditation as a Biological Resource Center according to the NIT-DICLA-061. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  12. Thermo-fluidic devices and materials inspired from mass and energy transport phenomena in biological system

    Institute of Scientific and Technical Information of China (English)

    Jian XIAO; Jing LIU

    2009-01-01

    Mass and energy transport consists of one of the most significant physiological processes in nature, which guarantees many amazing biological phenomena and activ-ities. Borrowing such idea, many state-of-the-art thermo-fluidic devices and materials such as artificial kidneys, carrier erythrocyte, blood substitutes and so on have been successfully invented. Besides, new emerging technologies are still being developed. This paper is dedicated to present-ing a relatively complete review of the typical devices and materials in clinical use inspired by biological mass and energy transport mechanisms. Particularly, these artificial thermo-fluidic devices and materials will be categorized into organ transplantation, drug delivery, nutrient transport, micro operation, and power supply. Potential approaches for innovating conventional technologies were discussed, corresponding biological phenomena and physical mechan-isms were interpreted, future promising mass-and-energy-transport-based bionic devices were suggested, and prospects along this direction were pointed out. It is expected that many artificial devices based on biological mass and energy transport principle will appear to better improve vari-ous fields related to human life in the near future.

  13. Development of High-frequency Soft Magnetic Materials for Power Electronics

    Directory of Open Access Journals (Sweden)

    LIU Jun-chang

    2017-05-01

    Full Text Available The new requirements of high-frequency magnetic properties are put forward for electronic components with the rapid development of power electronics industry and the use of new electromagnetic materials. The properties of magnetic core, which is the key unit of electronic components, determine the performance of electronic components directly. Therefore, it's necessary to study the high-frequency soft magnetic materials. In this paper, the development history of four types of soft magnetic materials was reviewed. The advantages and disadvantages of each kind of soft magnetic materials and future development trends were pointed out. The emphases were placed on the popular soft magnetic composite materials in recent years. The tendency is to develop high-frequency soft magnetic composite materials with the particle size controllable, uniform coating layer on the core and a mass production method from laboratory to industrialization.

  14. A Study on the Thermal Neutron Filter for the Irradiation of Electronic Materials at HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Seong Woo; Kim, Sung Ryul; Park, Seung Jae; Shin, Yoon Taeg; Cho, Man Soon; Cho, Kee Nam [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The representative example is a technique of making the semiconductor with the transmutation using the pure Si. This NTD (Neutron Transmutation Doping) Si is used as a high-quality semiconductor because it has a uniform resistance. Likewise, the electronic materials are being investigated to improve the performance of material using the neutron irradiation method. The mechanism for reaction between the electronic materials and the neutrons depends on the energy of the neutron. Capturing reaction by thermal neutrons causes the transmutation and a lot of defects are made by fast neutrons. The study for the effect by such neutron energy is necessary to understand the performance improvement of the irradiated electronic materials. The thermal neutron filter was investigated to be used for the irradiation of electronic materials at HANARO. IP irradiation hole was selected and the irradiation device was designed. The analysis was conducted considering four candidate materials.

  15. Electron bombardment cross-linking of coating materials

    International Nuclear Information System (INIS)

    Mileo, J.-C.

    1976-01-01

    The use of medium-power electron accelerators to cure paints and varnishes and to make them insoluble is described by making a special analysis of the physico-chemical aspect of the process. The following points in particular are examined: the effect of radiation on matter; general aspects of radiochemical polymerization, and the application of radiation polymerization to varnish drying. A quick review is then made of problems linked to the choice of radiation and to the influence of the oxygen in air. An electron accelerator and a method of calorimetric dosimetery are described [fr

  16. Electron beam disruption simulation of first wall material

    International Nuclear Information System (INIS)

    Quataert, D.; Brossa, F.; Moretto, P.; Rigon, G.

    1984-01-01

    The destructive effect of plasma disruptions on first wall material and limiters has been predicted and models have been made to study their behaviour under intensive pulsed energy deposition. The results presented here give a full description of qualitative and semi-quantitative results obtained for several materials (Mo, stainless steel, Cu, Al, Inconel, etc.) under various experimental conditions. Examples are given of specific defects such as: evaporation, melting, void and crack formation and recrystallization of the underlying material. Methods for the evaluation of deposited energy and beam dimensions are also presented. (author)

  17. Electron beam accelerator at BARC-BRIT complex - electron beam processing of materials and industrial utilization

    International Nuclear Information System (INIS)

    Khader, S.A.; Patkari, R.K.; Sharma, K.S.S.

    2013-01-01

    During the last decade, the 2MeV/20kW electron beam (EB) accelerator located at BARC-BRIT complex, Vashi has been successfully utilised for non-thermal applications to develop speciality products useful for the industry. Polymer materials are exposed to high energy electrons to induce crosslinking and degradation reactions in a number of industrial products without the use of external chemicals and additives. Various EB crosslinked products viz. PE O-rings, automotive components, automobile tyres, electrical insulations, etc have been found to be much superior in quality compared to those produced conventionally. A process has been developed to enhance colours in the polished diamonds and gem stones using EB irradiation at the facility which has attracted much attention in the Indian diamond industry as a value-addition process. Recycling of polymer waste processed under EB to produce microfine PTFE powder, to reuse in automobile industry etc. has shown good potential for the industrial use. The process feasibility both in terms of economics and technology have been amply demonstrated on a technological scale by installing special conveyors at our facility for irradiating various industrial products. Around 100 km cable insulations, 1.5 million PE O-rings and more than 40000 carats of polished diamonds have been processed in our facility over a period of time on commercial scale. Encouraged with the results, Indian private entrepreneurs have set up dedicated EB machines in some of the most significant industries producing wire and cables, electrical gadgets based on polymer composites, automobile tyres and diamonds. The products are unique in properties and are in some cases, became import substitutes. The industry is now fully geared up to adapt the technology by realising the advantages viz ease in adaptability, convenient, safe and environmental-friendly nature. Encouraged by the process demonstrations, while five EB accelerators were setup and are in operation

  18. Searching for biological traces on different materials using a forensic light source and infrared photography.

    Science.gov (United States)

    Sterzik, V; Panzer, S; Apfelbacher, M; Bohnert, M

    2016-05-01

    Because biological traces often play an important role in the investigation process of criminal acts, their detection is essential. As they are not always visible to the human eye, tools like a forensic light source or infrared photography can be used. The intention of the study presented was to give advice how to visualize biological traces best. Which wavelengths and/or filters give the best results for different traces on different fabrics of different colors? Therefore, blood (undiluted and diluted), semen, urine, saliva, and perspiration have been examined on 29 different materials.

  19. Determination of silicon in biological and botanical reference materials by epithermal INAA and Compton suppression

    International Nuclear Information System (INIS)

    Landsberger, S.; Peshev, S.; Becker, D.A.

    1994-01-01

    Silicon determination in sixteen botanical and biological standard reference materials is described using the 29 Si(n, p) 29 Al reaction through instrumental epithermal neutron activation analysis and Compton suppression gamma-ray spectroscopy. By simultaneous utilization of both cadmium and boron epithermal filters along with anticoincidence gamma-counting, detection limits as low as 12 ppm were obtained for certain matrices, much lower than previously reported values for this type of analysis. The method is applicable to many botanical and biological matrices and is attractive with its interference free, purely instrumental nature, compared with methods using the 28 Si(n, p) 28 Al reaction or chemical separation techniques. ((orig.))

  20. Electron Acceptor Materials Engineering in Colloidal Quantum Dot Solar Cells

    KAUST Repository

    Liu, Huan; Tang, Jiang; Kramer, Illan J.; Debnath, Ratan; Koleilat, Ghada I.; Wang, Xihua; Fisher, Armin; Li, Rui; Brzozowski, Lukasz; Levina, Larissa; Sargent, Edward H.

    2011-01-01

    -ion-doped sol-gel-derived titanium dioxide electrodes produce a tunable-bandedge, well-passivated materials platform for CQD solar cell optimization. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Hybrid Van Der Waals Materials In Next-Generation Electronics

    Data.gov (United States)

    National Aeronautics and Space Administration — In nature, there exists a class of materials which are inherently two-dimensional (2D). Although they form solid 3D structures, the individual atoms have strong...

  2. Electron holography for the study of nanomagnetic materials

    DEFF Research Database (Denmark)

    Thomas, John Meurig; Simpson, Edward T.; Kasama, Takeshi

    2008-01-01

    provide important quantitative information, with nanometer-scale spatial resolution, pertaining to such materials’ magnetic properties. In this Account, with the aid of representative examples embracing solid-state chemistry, geochemistry, and bio-inorganic phenomena, we illustrate how off-axis electron...

  3. Computational Nanotechnology of Molecular Materials, Electronics and Machines

    Science.gov (United States)

    Srivastava, D.; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    This viewgraph presentation covers carbon nanotubes, their characteristics, and their potential future applications. The presentation include predictions on the development of nanostructures and their applications, the thermal characteristics of carbon nanotubes, mechano-chemical effects upon carbon nanotubes, molecular electronics, and models for possible future nanostructure devices. The presentation also proposes a neural model for signal processing.

  4. Evaluation on electrical resistivity of silicon materials after electron ...

    Indian Academy of Sciences (India)

    Administrator

    3Department of Physics, Balochistan University of Information Technology, Engineering and Management Sciences, ... 1 m3, an electron beam gun with an accelerating voltage of 30 kV ... interface formed in figure 1b–e, which is not exactly at.

  5. Exposure of space electronics and materials to ionizing radiation

    DEFF Research Database (Denmark)

    Korsbech, Uffe C C

    1996-01-01

    Describes the methods and sources available for irradiation of space instruments developed at the Department of Automation. Methods for calculations and measurements of fluences and doses are also described. The sources are gamma-rays from iridium-192 and cobalt-60, 30 MeV protons, 10 MeV electrons...

  6. Scanning electron microscope facility for examination of radioactive materials

    International Nuclear Information System (INIS)

    Gibson, J.R.; Braski, D.N.

    1985-02-01

    An AMRAY model 1200B scanning electron microscope was modified to permit remote examination of radioactive specimens. Features of the modification include pneumatic vibration isolation of the column, motorized stage controls, improvements for monitoring vacuum, and a system for changing filaments without entering the hot cell

  7. Organizational influence on the occurrence of work accidents involving exposure to biological material.

    Science.gov (United States)

    Marziale, Maria Helena Palucci; Rocha, Fernanda Ludmilla Rossi; Robazzi, Maria Lúcia do Carmo Cruz; Cenzi, Camila Maria; dos Santos, Heloisa Ehmke Cardoso; Trovó, Marli Elisa Mendes

    2013-01-01

    to analyze work accidents involving exposure to biological materials which took place among personnel working in nursing and to evaluate the influence of the organizational culture on the occurrence of these accidents. a retrospective, analytical study, carried out in two stages in a hospital that was part of the Network for the Prevention of Work Accidents. The first stage involved the analysis of the characteristics of the work accidents involving exposure to biological materials as recorded over a seven-year period by the nursing staff in the hospital studied, and registered in the Network databank. The second stage involved the analysis of 122 nursing staff members' perception of the institutional culture, who were allocated to the control group (workers who had not had an accident) and the case group (workers who had had an accident). 386 accidents had been recorded: percutaneous lesions occurred in 79% of the cases, needles were the materials involved in 69.7% of the accidents, and in 81.9% of the accident there was contact with blood. Regarding the influence of the organizational culture on the occurrence of accidents, the results obtained through the analysis of the two groups did not demonstrate significant differences between the average scores attributed by the workers in each organizational value or practice category. It is concluded that accidents involving exposure to biological material need to be avoided, however, it was not possible to confirm the influence of organizational values or practices on workers' behavior concerning the occurrence of these accidents.

  8. Treatment of textiles industrial wastewater by electron beam and biological treatment (sbr)

    International Nuclear Information System (INIS)

    Khomsaton Abu Bakar; Khairul Zaman Mohd Dahlan; Zulkafli Ghazali; Ting Teo Ming

    2008-08-01

    Study of treating textiles industrial wastewater with combined of electron beam and Tower Style Biological Treatment (TSB) was investigated in Korea. In this project, textiles wastewater was also treated with electron beam, but hybrid with Sequencing Batch Reactor (SBR). The purpose of this research is to develop combined electron beam treatment with existing biological treatment facility (SBR), of textile industries in Malaysia. The objectives of this project are to determine the effective irradiation parameter for treatment and to identify effective total retention time in SBR system. To achieve the objective, samples fill in polypropyle tray were irradiated at 1 MeV, 20 mA and 1 MeV ,5 mA at doses 11, 20, 30, 40 and 50 kGy respectively. Raw effluent and two series of irradiated effluent at 1 MeV 20 mA (11, 20, 30, 40 and 50 kGy) and 1 MeV 5 mA (11, 20, 30, 40 and 50 kGy) were then treated in SBR system. Samples were analysed at 6, 14 and 20 hrs after aeration in the SBR. The results show that, average reduction in BOD was about 2-11% after irradiated at 5 mA, and the percentage increased to 21-73% after treatment in SBR system. At 20 mA, BOD reduced to 7-29% during irradiation and the value increased to 57-87% after treatment in SBR system. (Author)

  9. Electron beam irradiation to the allogeneic, xenogenic and synthetic bone materials

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Soung Min; Park, Min Woo; Jeong, Hyun Oh [School of Dentistry Seoul National University, Seoul (Korea, Republic of); and others

    2013-07-01

    For the development of the biocompatible bony regeneration materials, allogenic, xenogenic and synthetic bone were irradiated by electron beam to change the basic components and structures. For the efficient electron beam irradiating condition of these allogenic, xenogenic and artificial bone substitutes, the optimal electron beam energy and their individual dose were established, to maximize the bony regeneration capacity. Commercial products of four allogenic bones, such as Accell (ISOTIS OrthogBiologics Co., USA), Allotis (Korea Bone Bank Co., Korea), Oragraft (LifeNet Co., USA), and Orthoblast (Integra Orthobiologics Inc., USA), six xenogenic bones, such as BBP (OscoTec Co., Korea), Bio-cera (OscoTec Co., Korea), Bio-oss (Geistlich Pharma AG, Switzerland), Indu-cera (OscoTec Co., Korea), OCS-B (Nibec Co., Korea), and OCS-H (Nibec Co., Korea), and six synthetic bones, such as BMP (Couellmedi Co., Korea), BoneMedik (Meta Biomed Co., Korea), Bone plus (Megagen Co., Korea), MBCP (Biomatlante Co., France), Osteon (Genoss Co., Korea), and Osteogen (Impladent LTD., USA), were used. We used 1.0 and 2.0 MeV superconduction accelerator, and/or microtrone with different individual 60, 120 kGy irradiation dose. Different dose irradiated specimens were divided 6 portions each, so total 360 groups were prepared. 4 portions were analyzed each by elementary analysis using FE-SEM (Field Emission Scanning Microscopy) and another 2 portions were grafted to the calvarial defect of Sprague-Dawley rat, following histologic, immunohistochemical analysis and TEM study were processed at the 8th and 16th weeks, in vivo. This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MEST)

  10. Quantifying electronic band interactions in van der Waals materials using angle-resolved reflected-electron spectroscopy.

    Science.gov (United States)

    Jobst, Johannes; van der Torren, Alexander J H; Krasovskii, Eugene E; Balgley, Jesse; Dean, Cory R; Tromp, Rudolf M; van der Molen, Sense Jan

    2016-11-29

    High electron mobility is one of graphene's key properties, exploited for applications and fundamental research alike. Highest mobility values are found in heterostructures of graphene and hexagonal boron nitride, which consequently are widely used. However, surprisingly little is known about the interaction between the electronic states of these layered systems. Rather pragmatically, it is assumed that these do not couple significantly. Here we study the unoccupied band structure of graphite, boron nitride and their heterostructures using angle-resolved reflected-electron spectroscopy. We demonstrate that graphene and boron nitride bands do not interact over a wide energy range, despite their very similar dispersions. The method we use can be generally applied to study interactions in van der Waals systems, that is, artificial stacks of layered materials. With this we can quantitatively understand the 'chemistry of layers' by which novel materials are created via electronic coupling between the layers they are composed of.

  11. A geometric initial guess for localized electronic orbitals in modular biological systems

    Energy Technology Data Exchange (ETDEWEB)

    Beckman, P. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of Chicago, IL (United States); Fattebert, J. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lau, E. Y. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Osei-Kuffuor, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-11

    Recent first-principles molecular dynamics algorithms using localized electronic orbitals have achieved O(N) complexity and controlled accuracy in simulating systems with finite band gaps. However, accurately deter- mining the centers of these localized orbitals during simulation setup may require O(N3) operations, which is computationally infeasible for many biological systems. We present an O(N) approach for approximating orbital centers in proteins, DNA, and RNA which uses non-localized solutions for a set of fixed-size subproblems to create a set of geometric maps applicable to larger systems. This scalable approach, used as an initial guess in the O(N) first-principles molecular dynamics code MGmol, facilitates first-principles simulations in biological systems of sizes which were previously impossible.

  12. Removal of diclofenac from surface water by electron beam irradiation combined with a biological aerated filter

    Science.gov (United States)

    He, Shijun; Wang, Jianlong; Ye, Longfei; Zhang, Youxue; Yu, Jiang

    2014-12-01

    The degradation of DCF was investigated in aqueous solution by using electron beam (EB) technology. When the initial concentration was between 10 and 40 mg/L, almost 100% of the DCF was degraded at a dose of 0.5 kGy. However, only about 6.5% of DCF was mineralized even at 2 kGy according to total organic carbon (TOC) measurements. A combined process of EB and biological aerated filter (BAF) was therefore developed to enhance the treatment of DCF contaminated surface water. The effluent quality of combined process was substantially improved by EB pretreatment due to the degradation of DCF and related intermediates. Both irradiation and biological treatment reduced the toxicity of the treated water. The experimental results showed that EB is effective for removing DCF from artificial aqueous solution and real surface water.

  13. Strongly correlated electron materials. I. Theory of the quasiparticle structure

    International Nuclear Information System (INIS)

    Lopez-Aguilar, F.; Costa-Quintana, J.; Puig-Puig, L.

    1993-01-01

    In this paper we give a method for analyzing the renormalized electronic structure of the Hubbard systems. The first step is the determination of effective interactions from the random-phase approximation (RPA) and from an extended RPA (ERPA) that introduces vertex effects within the bubble polarization. The second step is the determination of the density of states deduced from the spectral functions. Its analysis leads us to conclude that these systems can exhibit three types of resonances in their electronic structures: the lower-, middle-, and upper-energy resonances. Furthermore, we analyze the conditions for which there is only one type of resonance and the causes that lead to the disappearance of the heavy-fermion state. We finally introduce the RPA and ERPA effective interactions within the strong-coupling theory and we give the conditions for obtaining coupling and superconductivity

  14. Application of phase change materials in thermal management of electronics

    International Nuclear Information System (INIS)

    Kandasamy, Ravi; Wang Xiangqi; Mujumdar, Arun S.

    2007-01-01

    Application of a novel PCM package for thermal management of portable electronic devices was investigated experimentally for effects of various parameters e.g. power input, orientation of package, and various melting/freezing times under cyclic steady conditions. Also, a two-dimensional numerical study was made and compared the experimental results. Results show that increased power inputs increase the melting rate, while orientation of the package to gravity has negligible effect on the thermal performance of the PCM package. The thermal resistance of the device and the power level applied to the PCM package are of critical importance for design of a passive thermal control system. Comparison with numerical results confirms that PCM-based design is an excellent candidate design for transient electronic cooling applications

  15. Electronic structure characterization and bandgap engineering of solar hydrogen materials

    International Nuclear Information System (INIS)

    Guo, Jinghua

    2007-01-01

    Bandgap, band edge positions as well as the overall band structure of semiconductors are of crucial importance in photoelectrochemical and photocatalytic applications. The energy position of the band edge level can be controlled by the electronegativity of the dopants, the pH of the solution (flatband potential variation of 60 mV per pH unit), as well as by quantum confinement effects. Accordingly, band edges and bandgap can be tailored to achieve specific electronic, optical or photocatalytic properties. Synchrotron radiation with photon energy at or below 1 keV is giving new insight into such areas as condensed matter physics and extreme ultraviolet optics technology. In the soft x-ray region, the question tends to be, what are the electrons doing as they migrated between the atoms. In this paper, I will present a number of soft x-ray spectroscopic study of nanostructured 3d metal compounds Fe 2 O 3 and ZnO

  16. The Structural Characterisation of Risk in the R&D Process of Functional Raw Materials for Electronic Devices

    OpenAIRE

    Chikamori, Yoji; Nasu, Seigo

    2017-01-01

    The electronic materials and electronics device industries remain important to Japan in spite of the general decline of the Japanese electronics industry. There is risk and uncertainty when developing functional materials in the electronics industry. However, studies examining the uncertainty and risk variables in the development of functional materials are scarce. This study examines incremental research and development (R&D) developed for raw functional materials for electronics. Our analys...

  17. Electron Bio-Imaging Centre (eBIC): the UK national research facility for biological electron microscopy.

    Science.gov (United States)

    Clare, Daniel K; Siebert, C Alistair; Hecksel, Corey; Hagen, Christoph; Mordhorst, Valerie; Grange, Michael; Ashton, Alun W; Walsh, Martin A; Grünewald, Kay; Saibil, Helen R; Stuart, David I; Zhang, Peijun

    2017-06-01

    The recent resolution revolution in cryo-EM has led to a massive increase in demand for both time on high-end cryo-electron microscopes and access to cryo-electron microscopy expertise. In anticipation of this demand, eBIC was set up at Diamond Light Source in collaboration with Birkbeck College London and the University of Oxford, and funded by the Wellcome Trust, the UK Medical Research Council (MRC) and the Biotechnology and Biological Sciences Research Council (BBSRC) to provide access to high-end equipment through peer review. eBIC is currently in its start-up phase and began by offering time on a single FEI Titan Krios microscope equipped with the latest generation of direct electron detectors from two manufacturers. Here, the current status and modes of access for potential users of eBIC are outlined. In the first year of operation, 222 d of microscope time were delivered to external research groups, with 95 visits in total, of which 53 were from unique groups. The data collected have generated multiple high- to intermediate-resolution structures (2.8-8 Å), ten of which have been published. A second Krios microscope is now in operation, with two more due to come online in 2017. In the next phase of growth of eBIC, in addition to more microscope time, new data-collection strategies and sample-preparation techniques will be made available to external user groups. Finally, all raw data are archived, and a metadata catalogue and automated pipelines for data analysis are being developed.

  18. Method for coating a resinous coating material. [electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ino, T; Fujioka, S; Mibae, J; Takahashi, M

    1968-07-13

    The strength, flexibility and durability of a vinyl chloride resin, acryl resin and the like are improved. This method of application comprises the steps of applying and thereafter radically curing a mixture composed of a polymer (II) having double bond(s) on its side chain and an ethylenic unsaturated monomer, said polymer (II) being obtained by the reaction between an unsaturated carboxylic acid or anhydride represented by the formula XCH = CHY (X = (CH/sub 2/)sub(n)COOH, where 0 <= n <= 2, Y = COOR/sub 1/ or R/sub 2/(R/sub 1/ and R/sub 2/ are hydrogen or an alkyl group having from 1 to 10 atoms of carbon)) and the acrylic copolymer (I), containing a hydroxyl group, obtained by copolymerization of 10 to 50% by weight of at least one selected from the group of beta-hydroxy alkyl acrylate, beta-hydroxy alkyl methacrylate, N-methylol acrylamide and N-methylol methacryl amide with at least one selected from the group of acrylic ester, methacrylic ester and stylene. The copolymer (I) can be obtained by the usual radical polymerization such as bulk polymerization, solution polymerization, suspension polymerization or the like. The polymer (II) is dissolved in the ethylenic unsaturated monomer and radically cured with radical polymerization catalysts or electron beams, etc. The energy range of the electron beams may be 0.1 to 3 MeV. Any type of electron accelerator may be used.

  19. Variations in erosive wear of metallic materials with temperature via the electron work function

    International Nuclear Information System (INIS)

    Huang, Xiaochen; Yu, Bin; Yan, X.G.; Li, D.Y.

    2016-01-01

    Mechanical properties of metals are intrinsically determined by their electron behavior, which is largely reflected by the electron work function (EWF or φ). Since the work function varies with temperature, the dependence of material properties on temperature could be predicted via variations in work function with temperature. Combining a hardness – φ relationship and the dependence of work function on temperature, a temperature-dependent model for predicting solid-particle erosion is proposed. Erosive wear losses of copper, nickel, and carbon steel as sample materials were measured at different temperatures. Results of the tests are consistent with the theoretical prediction. This study demonstrates a promising parameter, electron work function, for looking into fundamental aspects of wear phenomena, which would also help develop alternative methodologies for material design. - Highlights: • Metallic materials' wear resistance is influenced by temperature. • Electron work function (EWF) intrinsically determines materials' wear resistance. • An EWF-based temperature-dependent solid-particle erosion model is proposed.

  20. Applications of mass spectrometry in the trace element analysis of biological materials

    International Nuclear Information System (INIS)

    Moens, L.

    1997-01-01

    The importance of mass spectrometry for the analysis of biological material is illustrated by reviewing the different mass spectrometric methods applied and describing some typical applications published recently. Though atomic absorption spectrometry is used in the majority of analyses of biological material, most mass spectrometric methods have been used to some extent for trace element determination in biomedical research. The relative importance of the different methods is estimated by reviewing recent research papers. It is striking that especially inductively coupled plasma mass spectrometry is increasingly being applied, partly because the method can be used on-line after chromatographic separation, in speciation studies. Mass spectrometric methods prove to offer unique possibilities in stable isotope tracer studies and for this purpose also experimentally demanding methods such as thermal ionization mass spectrometry and accelerator mass spectrometry are frequently used. (orig.)

  1. THREE-DIMENSIONAL OBSERVATIONS ON THICK BIOLOGICAL SPECIMENS BY HIGH VOLTAGE ELECTRON MICROSCOPY

    Directory of Open Access Journals (Sweden)

    Tetsuji Nagata

    2011-05-01

    Full Text Available Thick biological specimens prepared as whole mount cultured cells or thick sections from embedded tissues were stained with histochemical reactions, such as thiamine pyrophosphatase, glucose-6-phosphatase, cytochrome oxidase, acid phosphatase, DAB reactions and radioautography, to observe 3-D ultrastructures of cell organelles producing stereo-pairs by high voltage electron microscopy at accerelating voltages of 400-1000 kV. The organelles demonstrated were Golgi apparatus, endoplasmic reticulum, mitochondria, lysosomes, peroxisomes, pinocytotic vesicles and incorporations of radioactive compounds. As the results, those cell organelles were observed 3- dimensionally and the relative relationships between these organelles were demonstrated.

  2. Evaluation of botanical reference materials for the determination of vanadium in biological samples

    International Nuclear Information System (INIS)

    Heydorn, K.; Damsgaard, E.

    1982-01-01

    Three botanical reference materials prepared by the National Bureau of Standards have been studied by neutron activation analysis to evaluate their suitability with respect to the determination of vanadium in biological samples. Various decomposition methods were applied in connection with chemical or radiochemical separations, and results for vanadium were compared with those found by purely instrumental neutron activation analysis. Significantly lower results indicate losses or incomplete dissolution, which makes SRM 1575 Pine Needles and SRM 1573 Tomato Leaves less satisfactory than SRM 1570 Spinach. A reference value of 1.15 mg/kg of this material is recommended, based on results from 3 different methods. All three materials are preferable to SRM 1571 Orchard Leaves, while Bowen's Kale remains the material of choice because of its lower concentration. (author)

  3. Escalation of terrorism? On the risk of attacks with chemical, biological, radiological and nuclear weapons or materials

    International Nuclear Information System (INIS)

    Nass, Jens

    2010-01-01

    The report on the risk of attacks with chemical, biological, radiological and nuclear weapons or materials covers the following topics: the variety of terrorism: ethnic-nationalistic, politically motivated, social revolutionary, political extremism, religious fanaticism, governmental terrorism; CBRN (chemical, biological, radiological, nuclear) weapons and materials: their availability and effectiveness in case of use; potential actor groups; prevention and counter measures, emergency and mitigating measures.

  4. Ab Initio Calculations of the Electronic Structures and Biological Functions of Protein Molecules

    Science.gov (United States)

    Zheng, Haoping

    2003-04-01

    The self-consistent cluster-embedding (SCCE) calculation method reduces the computational effort from M3 to about M1 (M is the number of atoms in the system) with unchanged calculation precision. So the ab initio, all-electron calculation of the electronic structure and biological function of protein molecule becomes a reality, which will promote new proteomics considerably. The calculated results of two real protein molecules, the trypsin inhibitor from the seeds of squash Cucurbita maxima (CMTI-I, 436 atoms) and the Ascaris trypsin inhibitor (912 atoms, two three-dimensional structures), are presented. The reactive sites of the inhibitors are determined and explained. The precision of structure determination of inhibitors are tested theoretically.

  5. Quantitative analysis of biological fluids by electron probe and X ray spectrometry

    International Nuclear Information System (INIS)

    Girod, Chantal

    1986-01-01

    In order to know the kidney normal operation and to have an insight on cellular transport mechanisms and hormonal regulations at the nephron level, a technique based on the use of an electron probe has been developed for the elemental analysis of micro-volumes of biological fluids. This academic document reports applications of this technique on animals on which such fluids have been sampled at different levels of the nephron. As these samples are available in too small volumes to be dosed by conventional methods, they have been quantitatively analysed by using an electronic probe based analyser in order to determine concentrations of all elements with an atomic number greater than that of carbon. After a presentation of the implemented method and hardware, the author thus describes how an analysis is performed, and reports and discusses an example (analysis conditions, data acquisition, data processing, minimum detectable concentration, reasons for measurement scattering)

  6. A method to determine site-specific, anisotropic fracture toughness in biological materials

    International Nuclear Information System (INIS)

    Bechtle, Sabine; Özcoban, Hüseyin; Yilmaz, Ezgi D.; Fett, Theo; Rizzi, Gabriele; Lilleodden, Erica T.; Huber, Norbert; Schreyer, Andreas; Swain, Michael V.; Schneider, Gerold A.

    2012-01-01

    Many biological materials are hierarchically structured, with highly anisotropic structures and properties on several length scales. To characterize the mechanical properties of such materials, detailed testing methods are required that allow precise and site-specific measurements on several length scales. We propose a fracture toughness measurement technique based on notched focused ion beam prepared cantilevers of lower and medium micron size scales. Using this approach, site-specific fracture toughness values in dental enamel were determined. The usefulness and challenges of the method are discussed.

  7. Laws and regulations associated with ownership of human biological material in South Africa

    Directory of Open Access Journals (Sweden)

    Kishen Mahesh

    2015-05-01

    Full Text Available Ownership with regard to human biological material (HBM is addressed to some extent within South African law, specifically in chapter eight of the National Health Act (NHA and its associated regulations. However, members of the legal fraternity struggle to conceptualise ownership of such materials without objectifying a person or people and risking reducing such individuals to a state of property. This then infers a reduction in human dignity by rendering one-self or parts of that same self as a commodity. The complexity of the issue raises much debate both legally as well as ethically. 

  8. Analysis of occupational accidents with biological material among professionals in pre-hospital services

    OpenAIRE

    Oliveira,Adriana Cristina de; Paiva,Maria Henriqueta Rocha Siqueira

    2013-01-01

    OBJECTIVE: To estimate the prevalence of accidents due to biological material exposure, the characteristics and post-accident conduct among professionals of pre-hospital services of the four municipalities of Minas Gerais, Brazil. METHOD: A cross-sectional study, using a structured questionnaire that was developed to enable the calculation of prevalence, descriptive analysis and analytical analysis using logistic regression. The study included 228 professionals; the prevalence of accidents du...

  9. Determination of element concentrations in biological reference materials by solid sampling and other analytical methods

    International Nuclear Information System (INIS)

    Schauenburg, H.; Weigert, P.

    1992-01-01

    Using solid sampling with graphite furnace atomic absorption spectrometry (GFAAS), values for cadmium, copper, lead and zinc in six biological reference materials were obtained from up to four laboratories participating in three collaborative studies. These results are compared with those obtained with other methods used in routine analysis from laboratories of official food control. Under certain conditions solid sampling with GFAAS seems to be suitable for routine analysis as well as conventional methods. (orig.)

  10. Standard operating procedure for combustion of 14C - samples with OX-500 biological material oxidizer

    International Nuclear Information System (INIS)

    Nashriyah Mat.

    1995-01-01

    This procedure is for the purpose of safe operation of OX-500 biological material oxidizer. For ease of operation, the operation flow chart (including testing the system and sample combustion) and end of day maintenance flow chart were simplified. The front view, diagrams and switches are duly copied from operating manual. Steps on sample preparation are also included for biotic and a biotic samples. This operating procedure is subjected to future reviews

  11. Determination of arsenic in biological materials using ammonium molybdate labelled with 99Mo

    International Nuclear Information System (INIS)

    Maruyama, Y.; Nagaoka, Y.

    1983-01-01

    A new radiometric method for the determination of arsenic in biological materials has been developed. An excess of ammonium molybdate labelled with 99 Mo was added to the sample solution and the arsenomolybdic acid formed was extracted into n-butyl alcohol and ethyl acetate mixture. The activity of the organic phase was directly proportional to the amount of arsenic. The method was applied for the determination of arsenic in Orchard Leaves obtained from the National Bureau of Standards. (author)

  12. Dissolution chemistry and biocompatibility of single-crystalline silicon nanomembranes and associated materials for transient electronics.

    Science.gov (United States)

    Hwang, Suk-Won; Park, Gayoung; Edwards, Chris; Corbin, Elise A; Kang, Seung-Kyun; Cheng, Huanyu; Song, Jun-Kyul; Kim, Jae-Hwan; Yu, Sooyoun; Ng, Joanne; Lee, Jung Eun; Kim, Jiyoung; Yee, Cassian; Bhaduri, Basanta; Su, Yewang; Omennetto, Fiorenzo G; Huang, Yonggang; Bashir, Rashid; Goddard, Lynford; Popescu, Gabriel; Lee, Kyung-Mi; Rogers, John A

    2014-06-24

    Single-crystalline silicon nanomembranes (Si NMs) represent a critically important class of material for high-performance forms of electronics that are capable of complete, controlled dissolution when immersed in water and/or biofluids, sometimes referred to as a type of "transient" electronics. The results reported here include the kinetics of hydrolysis of Si NMs in biofluids and various aqueous solutions through a range of relevant pH values, ionic concentrations and temperatures, and dependence on dopant types and concentrations. In vitro and in vivo investigations of Si NMs and other transient electronic materials demonstrate biocompatibility and bioresorption, thereby suggesting potential for envisioned applications in active, biodegradable electronic implants.

  13. X-ray, neutron, and electron scattering. Report of a materials sciences workshop

    International Nuclear Information System (INIS)

    1977-08-01

    The ERDA Workshop on X-ray, Neutron, and Electron Scattering to assess needs and establish priorities for energy-related basic research on materials. The general goals of the Workshop were: (1) to review various energy technologies where x-ray, neutron, and electron scattering techniques might make significant contributions, (2) to identify present and future materials problems in the energy technologies and translate these problems into requirements for basic research by x-ray, neutron, and electron scattering techniques, (3) to recommend research areas utilizing these three scattering techniques that should be supported by the DPR Materials Sciences Program, and (4) to assign priorities to these research areas

  14. Under-reporting of accidents involving biological material by nursing professionals at a Brazilian emergency hospital.

    Science.gov (United States)

    Facchin, Luiza Tayar; Gir, Elucir; Pazin-Filho, Antonio; Hayashida, Miyeko; da Silva Canini, Silvia Rita Marin

    2013-01-01

    Pathogens can be transmitted to health professionals after contact with biological material. The exact number of infections deriving from these events is still unknown, due to the lack of systematic surveillance data and under-reporting. A cross-sectional study was carried out, involving 451 nursing professionals from a Brazilian tertiary emergency hospital between April and July 2009. Through an active search, cases of under-reporting of occupational accidents with biological material by the nursing team were identified by means of individual interviews. The Institutional Review Board approved the research project. Over half of the professionals (237) had been victims of one or more accidents (425 in total) involving biological material, and 23.76% of the accidents had not been officially reported using an occupational accident report. Among the underreported accidents, 53.47% were percutaneous and 67.33% were bloodborne. The main reason for nonreporting was that the accident had been considered low risk. The under-reporting rate (23.76%) was low in comparison with other studies, but most cases of exposure were high risk.

  15. Clinical treatment adherence of health care workers and students exposed to potentially infectious biological material

    Directory of Open Access Journals (Sweden)

    Maria Cristina Mendes de Almeida

    2015-04-01

    Full Text Available OBJECTIVE To assess adherence to clinical appointments by health care workers (HCW and students who suffered accidents with potentially infectious biological material. METHOD A retrospective cross-sectional study that assessed clinical records of accidents involving biological material between 2005 and 2010 in a specialized unit. RESULTS A total of 461 individuals exposed to biological material were treated, of which 389 (84.4% were HCWs and 72 (15.6% students. Of the 461 exposed individuals, 307 (66.6% attended a follow-up appointment. Individuals who had suffered an accident with a known source patient were 29 times more likely to show up to their scheduled follow-up appointments (OR: 29.98; CI95%: 16.09-55.83. CONCLUSION The predictor in both univariate and multivariate analyses for adherence to clinical follow-up appointment was having a known source patient with nonreactive serology for the human immunodeficiency virus and/or hepatitis B and C.

  16. Analysis of occupational accidents with biological material among professionals in pre-hospital services.

    Science.gov (United States)

    de Oliveira, Adriana Cristina; Paiva, Maria Henriqueta Rocha Siqueira

    2013-02-01

    To estimate the prevalence of accidents due to biological material exposure, the characteristics and post-accident conduct among professionals of pre-hospital services of the four municipalities of Minas Gerais, Brazil. A cross-sectional study, using a structured questionnaire that was developed to enable the calculation of prevalence, descriptive analysis and analytical analysis using logistic regression. The study included 228 professionals; the prevalence of accidents due to biological material exposure was 29.4%, with 49.2% percutaneous, 10.4% mucousal, 6.0% non-intact skin, and 34.4% intact skin. Among the professionals injured, those that stood out were nursing technicians (41.9%) and drivers (28.3%). Notification of the occurrence of the accident occurred in 29.8% of the cases. Percutaneous exposure was associated with time of work in the organization (OR=2.51, 95% CI: 1.18 to 5.35, paccidents with biological material should be encouraged, along with professional evaluation/monitoring.

  17. Biological export of radioactive materials from a leaching pond in SE Idaho

    International Nuclear Information System (INIS)

    Millard, Jere B.

    1978-01-01

    A radioecological investigation was conducted to quantify biological export of radioactive materials from a test reactor area leaching pond located on the Idaho National Engineering Laboratory site in southeast Idaho. An estimated 42,000 Ci have been discharged to the pond since 1952. Approximately 35 gamma emitting radionuclides are detectable in unfiltered water. Biomass estimates and mean radionuclide concentrations were determined for major pond compartments. A radionuclide inventory of the pond ecosystem was constructed listing totals for radioactivity present in each compartment. Mean concentrations of predominant radionuclides and population census data were used to estimate biologically exported materials. Particular attention was paid to migrant waterfowl, a resident population of barn swallows (Hirundo rustica), and nesting shore birds. Whole body gamma spectra indicated 15 or more detectable fission and activation products associated with swallows and shore birds, and 20 or more for waterfowl. Concentration factors relative to filtered pond water were also calculated. Finally, biologically exported radioactive materials were compared with total amounts present in the pond. (author)

  18. Hydrogen, metals, bifurcating electrons, and proton gradients: the early evolution of biological energy conservation.

    Science.gov (United States)

    Martin, William F

    2012-03-09

    Life is a persistent, self-specified set of far from equilibrium chemical reactions. In modern microbes, core carbon and energy metabolism are what keep cells alive. In very early chemical evolution, the forerunners of carbon and energy metabolism were the processes of generating reduced carbon compounds from CO(2) and the mechanisms of harnessing energy as compounds capable of doing some chemical work. The process of serpentinization at alkaline hydrothermal vents holds promise as a model for the origin of early reducing power, because Fe(2+) in the Earth's crust reduces water to H(2) and inorganic carbon to methane. The overall geochemical process of serpentinization is similar to the biochemical process of methanogenesis, and methanogenesis is similar to acetogenesis in that both physiologies allow energy conservation from the reduction of CO(2) with electrons from H(2). Electron bifurcation is a newly recognized cytosolic process that anaerobes use generate low potential electrons, it plays an important role in some forms of methanogenesis and, via speculation, possibly in acetogenesis. Electron bifurcation likely figures into the early evolution of biological energy conservation. Copyright © 2011. Published by Elsevier B.V.

  19. Effect of ammonia and electron beam irradiation on lignocelulosic materials

    International Nuclear Information System (INIS)

    Mastro, N.L. del; Gennari, S.M.; Castagnet, A.C.G.

    1986-01-01

    Reports on some of the effects produced on sugarcane bagasse and eucaliptus wood saccharification by combining irradiation and NH 3 treatment. The samples irradiated at 10 5 Gy, 2x10 5 Gy and 5x10 5 Gy with an electron accelerator were treated with anhydrous gaseous ammonia. Cellulase complex from T. reesei was used for hydrolysis assays. Bromatological analysis and 'in vitro' digestibility tests were performed. The combination of EBI and ammonia treatments produced and increase in the saccharification yield, 'in vitro' digestibility and protein content for the two kinds of sample. (Author) [pt

  20. Analysis of archaeological materials through Scanning electron microscopy

    International Nuclear Information System (INIS)

    Camacho, A.; Tenorio C, D.; Elizalde, S.; Mandujano, C.; Cassiano, G.

    2005-01-01

    With the purpose to know the uses and the chemical composition of some cultural objects in the pre hispanic epoch this work presents several types of analysis for identifying them by means of the Scanning electron microscopy and its techniques as the Functional analysis of artifacts based on the 'tracks of use' analysis, also the X-ray spectroscopy and the X-ray dispersive energy (EDS) are mentioned, all of them allowing a major approach to the pre hispanic culture in Mexico. (Author)

  1. On genealogy of defect electron states in semiconductor materials

    International Nuclear Information System (INIS)

    Makhmudov, A.Sh.

    1984-01-01

    Main factors of formation of defect electron structure in semiconductors are considered. It is concluded on the basis of analysis of papers published earlier that it is necessary to take account of two factors: long- and short-range orders i.e. the nature of the atom interaction with the several nearest neighbours as well as crystal periodicity, correctly formulated boundary conditions. One of possible wayes of the given task realization is the combination of a traditional scheme of the solid body theory- the Green function method and the semiempirical quantum-chemical method of equivalent orbitales

  2. Polymeric and Molecular Materials for Advanced Organic Electronics

    Science.gov (United States)

    2011-07-25

    C8H17) films on SiO2 exhibit electron mobilities in air > 0.2 cm 2 /Vs. Electrochemistry reveals reduction potentials ~ 0.0 V vs. S.C.E.; hence...enable low-voltage single-walled carbon nanotube and ZnO nanowire transistors, and can be integrated with GaAs JFETs (Fig. 9). Because of the very...large mobilities achieved in such devices (e ~ 3000 cm 2 V -1 s -1 for ZnO Figure 9. Top. Schematic representation of the TFT components of an

  3. Dual-mode operation of 2D material-base hot electron transistors

    KAUST Repository

    Lan, Yann-Wen; Jr., Carlos M. Torres,; Zhu, Xiaodan; Qasem, Hussam; Adleman, James R.; Lerner, Mitchell B.; Tsai, Shin-Hung; Shi, Yumeng; Li, Lain-Jong; Yeh, Wen-Kuan; Wang, Kang L.

    2016-01-01

    Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (V-CB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (V-CB < 0). That is, our 2D material-base hot electron transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications.

  4. Dual-mode operation of 2D material-base hot electron transistors

    KAUST Repository

    Lan, Yann-Wen

    2016-09-01

    Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (V-CB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (V-CB < 0). That is, our 2D material-base hot electron transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications.

  5. PROCESS DEVELOPMENT FOR THE RECOVERY OF CRITICAL MATERIALS FROM ELECTRONIC WASTE

    Energy Technology Data Exchange (ETDEWEB)

    Lister, T. E.; Diaz, L. A.; Clark, G. G.; Keller, P.

    2016-09-01

    As electronic technology continues to evolve there is a growing need to develop processes which recover valuable material from antiquated technology. This need follows from the environmental challenges associated with the availability of raw materials and fast growing generation of electronic waste. Although just present in small quantities in electronic devices, the availability of raw materials, such as rare earths and precious metals, becomes critical for the production of high tech electronic devices and the development of green technologies (i.e. wind turbines, electric motors, and solar panels). Therefore, the proper recycling and processing of increasing volumes of electronic waste present an opportunity to stabilize the market of critical materials, reducing the demand of mined products, and providing a proper disposal and treatment of a hazardous waste stream. This paper will describe development and techno-economic assessment of a comprehensive process for the recovery of value and critical materials from electronic waste. This hydrometallurgical scheme aims to selectively recover different value segments in the materials streams (base metals, precious metals, and rare earths). The economic feasibility for the recovery of rare earths from electronic waste is mostly driven by the efficient recovery of precious metals, such as Au and Pd (ca. 80 % of the total recoverable value). Rare earth elements contained in magnets (speakers, vibrators and hard disk storage) can be recovered as a mixture of rare earths oxides which can later be reduced to the production of new magnets.

  6. Electronic structure characterization and bandgap engineeringofsolar hydrogen materials

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jinghua

    2007-11-01

    Bandgap, band edge positions as well as the overall band structure of semiconductors are of crucial importance in photoelectrochemical and photocatalytic applications. The energy position of the band edge level can be controlled by the electronegativity of the dopants, the pH of the solution (flatband potential variation of 60 mV per pH unit), as well as by quantum confinement effects. Accordingly, band edges and bandgap can be tailored to achieve specific electronic, optical or photocatalytic properties. Synchrotron radiation with photon energy at or below 1 keV is giving new insight into such areas as condensed matter physics and extreme ultraviolet optics technology. In the soft x-ray region, the question tends to be, what are the electrons doing as they migrated between the atoms. In this paper, I will present a number of soft x-ray spectroscopic study of nanostructured 3d metal compounds Fe{sub 2}O{sub 3} and ZnO.

  7. Hydrogen storage material, electrochemically active material, electrochemical cell and electronic equipment

    NARCIS (Netherlands)

    2008-01-01

    The invention relates to a hydrogen storage material comprising an alloy of magnesium. The invention further relates to an electrochemically active material and an electrochemical cell provided with at least one electrode comprising such a hydrogen storage material. Also, the invention relates to

  8. Biological shielding design and qualification of concreting process for construction of electron beam irradiation facility

    International Nuclear Information System (INIS)

    Petwal, V.C.; Kumar, P.; Suresh, N.; Parchani, G.; Dwivedi, J.; Thakurta, A.C.

    2011-01-01

    A technology demonstration facility for irradiation of food and agricultural products is being set-up by RRCAT at Indore. The facility design is based on linear electron accelerator with maximum beam power of 10 kW and can be operated either in electron mode at 10 MeV or photon modes at 5/7.5 MeV. Biological shielding has been designed in accordance with NCRP 51 to achieve dose rate at all accessible points outside the irradiation vault less than the permissible limit of 0.1 mR/hr. In addition to radiation attenuation property, concrete must have satisfactory mechanical properties to meet the structural requirements. There are number of site specific variables which affect the structural, thermal and radiological properties of concrete, leading to considerable difference in actual values and design values. Hence it is essential to establish a suitable site and environmental specific process to cast the concrete and qualify the process by experimental measurement. For process qualification we have cast concrete test blocks of different thicknesses up to 3.25 m and evaluated the radiological and mechanical properties by radiometry, ultrasonic and mechanical tests. In this paper we describe the biological shielding design of the facility and analyse the results of tests carried out for qualification of the process. (author)

  9. Universally-Usable Interactive Electronic Physics Instructional And Educational Materials

    Science.gov (United States)

    Gardner, John

    2000-03-01

    Recent developments of technologies that promote full accessibility of electronic information by future generations of people with print disabilities will be described. ("Print disabilities" include low vision, blindness, and dyslexia.) The guiding philosophy of these developments is that information should be created and transmitted in a form that is as display-independent as possible, and that the user should have maximum freedom over how that information is to be displayed. This philosophy leads to maximum usability by everybody and is, in the long run, the only way to assure truly equal access. Research efforts to be described include access to mathematics and scientific notation and to graphs, tables, charts, diagrams, and general object-oriented graphics.

  10. Evaluation of geologic materials to limit biological intrusion of low-level waste site covers

    International Nuclear Information System (INIS)

    Hakonson, T.E.; White, G.C.; Karlen, E.M.

    1982-01-01

    The long-term integrity of low-level waste shallow land burial sites is dependent on the interaction of physical, chemical, and biological factors that modify the waste containment system. This paper reports the preliminary results of a screening study to-determine the effectiveness of four biobarrier materials to stop plant root and animal penetration into simulated low-level wastes. Experiments employed 288 lysimeters consisting of 25-cm-diam PVC pipe, with four factors tested: plant species (alfalfa, barley, and sweet clover); top soil thickness (30 and 60 cm); biobarrier material (crushed tuff, bentonite clay, cobble, and cobble-gravel); and biobarrier thickness (clay-15, 30, and 45 cm, others 30, 60, and 90 cm). The crushed tuff, a sandy backfill material, offers little resistance to root and animal intrusion through the cover profile, while bentonite clay, cobble, and cobble-gravel combinations do reduce plant root and animal intrusion thorugh cover profiles. However, dessication of the clay barrier by invading plant roots may limit the usefulness of this material as a moisture and/or biological barrier. The cobble-gravel combination appears to be the best candidate for further testing on a larger scale because the gravel helps impede the imgration of soil into the cobble layer - the probable cause of failure of cobble-only biobarriers

  11. Determination of azide in biological fluids by use of electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Minakata, Kayoko; Suzuki, Osamu

    2005-01-01

    A simple and sensitive method has been developed for the determination of azide ion (N 3 - ) in biological fluids and beverages. The procedure was based on the formation of a ternary complex Cu(N 3 ) 2 (4-methylpyridine) x in benzene, followed by its detection by electron paramagnetic resonance. The complex in benzene showed a characteristic four-peak hyperfine structure with a g-value of 2.115 at room temperature. Cu 2+ reacted with N 3 - most strongly among common metals found in biological fluids. Several anions and metal ions in biological fluids did not interfere with the determination of N 3 - in the presence of large amounts of Cu 2+ and oxidants. In the present method, N 3 - at the concentration from 5 μM to 2 mM in 100 μl solution could be determined with the detection limit of 20 ng. The recoveries were more than 95% for N 3 - added to 100 μl of blood, urine, milk and beverages at 200 μM. Our method is recommendable because it takes less than 10 min to determine N 3 - and the produced complex is quite stable

  12. [Realistic theories of heavy electron and other strongly correlated materials

    International Nuclear Information System (INIS)

    1993-01-01

    Research on the following topics is summarized: non-perturbative treatments of multi-channel Kondo models, non-perturbative treatments of multi-band models for the quadrupolar fluctuation model of the cuprates, extension of the two-channel Kondo model to other materials and treatment of the infinite-dimensional Hubbard model within the Non-crossing approximation. Data on the specific heat of Y 0.8 U 0.2 Pd 3 and the c-axis susceptibility and specific heat of U in ThRu 2 Si are shown. 5 figs., 84 refs

  13. In situ and operando transmission electron microscopy of catalytic materials

    DEFF Research Database (Denmark)

    Crozier, Peter A.; Hansen, Thomas Willum

    2015-01-01

    measurements of gas-phase catalytic products. To overcome this deficiency, operando TEM techniques are being developed that combine atomic characterization with the simultaneous measurement of catalytic products. This article provides a short review of the current status and major developments......) is a powerful technique for revealing the atomic structures of materials at elevated temperatures in the presence of reactive gases. This approach can allow the structure-reactivity relations underlying catalyst functionality to be investigated. Thus far, ETEM has been limited by the absence of in situ...... in the application of ETEM to gas-phase catalysis over the past 10 years....

  14. Noncovalent Intermolecular Interactions in Organic Electronic Materials: Implications for the Molecular Packing vs Electronic Properties of Acenes

    KAUST Repository

    Sutton, Christopher

    2015-10-30

    Noncovalent intermolecular interactions, which can be tuned through the toolbox of synthetic chemistry, determine not only the molecular packing but also the resulting electronic, optical, and mechanical properties of materials derived from π-conjugated molecules, oligomers, and polymers. Here, we provide an overview of the theoretical underpinnings of noncovalent intermolecular interactions and briefly discuss the computational chemistry approaches used to understand the magnitude of these interactions. These methodologies are then exploited to illustrate how noncovalent intermolecular interactions impact important electronic properties-such as the electronic coupling between adjacent molecules, a key parameter for charge-carrier transport-through a comparison between the prototype organic semiconductor pentacene with a series of N-substituted heteropentacenes. Incorporating an understanding of these interactions into the design of organic semiconductors can assist in developing novel materials systems from this fascinating molecular class. © 2015 American Chemical Society.

  15. The determination of plutonium alpha activity in urine, faeces and biological materials

    International Nuclear Information System (INIS)

    Bains, M.E.D.

    1963-07-01

    Methods have been developed for the determination of plutonium alpha activity in urine, faeces and biological materials. The chemical stages involved give practically complete separation of all extraneous material from the plutonium, which is electrodeposited on to a 0.5 inch stainless steel disc to produce a thin high resolution source. The limit of detection is 0.025 μμc/sample (sixteen-hour count) when the sources are counted in a small scintillator counter, but is lowest when counted in a counter which counts particles of energy 5.05-5.25 MeV only, and which therefore discriminates against small quantities of α-active materials introduced with the reagents in the final electrodeposition stage of the process. (Any such alpha activity may readily be identified by alpha pulse height analysis). (author)

  16. Development and Applications Of Photosensitive Device Systems To Studies Of Biological And Organic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Gruner, Sol

    2012-01-20

    The primary focus of the grant is the development of new x-ray detectors for biological and materials work at synchrotron sources, especially Pixel Array Detectors (PADs), and the training of students via research applications to problems in biophysics and materials science using novel x-ray methods. This Final Progress Report provides a high-level overview of the most important accomplishments. These major areas of accomplishment include: (1) Development and application of x-ray Pixel Array Detectors; (2) Development and application of methods of high pressure x-ray crystallography as applied to proteins; (3) Studies on the synthesis and structure of novel mesophase materials derived from block co-polymers.

  17. An electromechanical material testing system for in situ electron microscopy and applications

    OpenAIRE

    Zhu, Yong; Espinosa, Horacio D.

    2005-01-01

    We report the development of a material testing system for in situ electron microscopy (EM) mechanical testing of nanostructures. The testing system consists of an actuator and a load sensor fabricated by means of surface micromachining. This previously undescribed nanoscale material testing system makes possible continuous observation of the specimen deformation and failure with subnanometer resolution, while simultaneously measuring the applied load electronically with nanonewton resolution...

  18. In-focus electron microscopy of frozen-hydrated biological samples with a Boersch phase plate

    Energy Technology Data Exchange (ETDEWEB)

    Barton, B.; Rhinow, D.; Walter, A.; Schroeder, R. [Max Planck Institute of Biophysics, Max-von-Laue Str. 3, 60438 Frankfurt am Main (Germany); Benner, G.; Majorovits, E.; Matijevic, M.; Niebel, H. [Carl Zeiss NTS GmbH, D-73447 Oberkochen (Germany); Mueller, H.; Haider, M. [CEOS GmbH, Englerstr. 26, 69126 Heidleberg (Germany); Lacher, M.; Schmitz, S.; Holik, P. [Caesar Research Center, Ludwig-Erhard-Allee 2, D-53175 Bonn (Germany); Kuehlbrandt, W., E-mail: werner.kuehlbrandt@mpibp-frankfurt.mpg.de [Max Planck Institute of Biophysics, Max-von-Laue Str. 3, 60438 Frankfurt am Main (Germany)

    2011-12-15

    We report the implementation of an electrostatic Einzel lens (Boersch) phase plate in a prototype transmission electron microscope dedicated to aberration-corrected cryo-EM. The combination of phase plate, C{sub s} corrector and Diffraction Magnification Unit (DMU) as a new electron-optical element ensures minimal information loss due to obstruction by the phase plate and enables in-focus phase contrast imaging of large macromolecular assemblies. As no defocussing is necessary and the spherical aberration is corrected, maximal, non-oscillating phase contrast transfer can be achieved up to the information limit of the instrument. A microchip produced by a scalable micro-fabrication process has 10 phase plates, which are positioned in a conjugate, magnified diffraction plane generated by the DMU. Phase plates remained fully functional for weeks or months. The large distance between phase plate and the cryo sample permits the use of an effective anti-contaminator, resulting in ice contamination rates of <0.6 nm/h at the specimen. Maximal in-focus phase contrast was obtained by applying voltages between 80 and 700 mV to the phase plate electrode. The phase plate allows for in-focus imaging of biological objects with a signal-to-noise of 5-10 at a resolution of 2-3 nm, as demonstrated for frozen-hydrated virus particles and purple membrane at liquid-nitrogen temperature. -- Highlights: Black-Right-Pointing-Pointer We implement an electrostatic Boersch phase plate into a dedicated prototypical TEM. Black-Right-Pointing-Pointer Phase contrast aberration-corrected electron microscope (PACEM) includes a diffraction magnification unit (DMU). Black-Right-Pointing-Pointer DMU minimizes obstruction of low spatial frequencies by the phase plate. Black-Right-Pointing-Pointer In-focus phase contrast generation is demonstrated for frozen-hydrated biological specimens.

  19. Mechanical properties of organic composite materials irradiated with 2 MeV electrons

    International Nuclear Information System (INIS)

    Egusa, S.; Kirk, M.A.; Birtcher, R.C.; Argonne National Lab., IL; Hagiwara, M.; Kawanishi, S.

    1983-01-01

    Four kinds of cloth-filled organic composites (filter: glass or carbon fiber; matrix; epoxy or polyimide resin) were irradiated with 2 MeV electrons at room temperature, and were examined with regard to the mechanical properties. Following irradiation the Young's (tensile) modulus of these composites remains practically unchanged even after irradiation up to 15.000 Mrad. The shear modulus and the ultimate strength, on the other hand, begin to decrease after the absorbed dose reaches about 2.000 Mrad for the glass/epoxy composite and about 5.000-10.000 Mrad for the other composites. This result is ascribed to the decrease in the capacity of load transfer from the matrix to the fiber due to the radiation damage at the interface, and the dose dependence is interpreted and formulated based on the mechanics of composite materials and the target theory used in radiation biology. As to the fracture behavior, the propagation energy increases from the beginning of irradiation. This result is attributed to the radiation-induced decrease in the bonding energy at the interface. (orig.)

  20. Magnetic field effects on runaway electron energy deposition in plasma facing materials and components

    International Nuclear Information System (INIS)

    Niemer, K.A.; Gilligan, J.G.

    1992-01-01

    This paper reports magnetic field effects on runaway electron energy deposition in plasma facing materials and components is investigated using the Integrated TIGER Series. The Integrated TIGER Series is a set of time-independent coupled electron/photon Monte Carlo transport codes which perform photon and electron transport, with or without macroscopic electric and magnetic fields. A three-dimensional computational model of 100 MeV electrons incident on a graphite block was used to simulate runawayelectrons striking a plasma facing component at the edge of a tokamak. Results show that more energy from runaway electrons will be deposited in a material that is in the presence of a magnetic field than in a material that is in the presence of no field. For low angle incident runaway electrons in a strong magnetic field, the majority of the increased energy deposition is near the material surface with a higher energy density. Electrons which would have been reflected with no field, orbit the magnetic field lines and are redeposited in the material surface, resulting in a substantial increase in surface energy deposition. Based on previous studies, the higher energy deposition and energy density will result in higher temperatures which are expected to cause more damage to a plasma facing component

  1. Increasing the lego of 2D electronics materials: silicene and germanene, graphene's new synthetic cousins

    Science.gov (United States)

    Le Lay, Guy; Salomon, Eric; Angot, Thierry; Eugenia Dávila, Maria

    2015-05-01

    The realization of the first Field Effect Transistors operating at room temperature, based on a single layer silicene channel, open up highly promising perspectives, e.g., typically, for applications in digital electronics. Here, we describe recent results on the growth, characterization and electronic properties of novel synthetic two-dimensional materials beyond graphene, namely silicene and germanene, its silicon and germanium counterparts.

  2. Nano-tomography of porous geological materials using focused ion beam-scanning electron microscopy

    NARCIS (Netherlands)

    Liu, Yang; King, Helen E.; van Huis, Marijn A.; Drury, Martyn R.; Plümper, Oliver

    2016-01-01

    Tomographic analysis using focused ion beam-scanning electron microscopy (FIB-SEM) provides three-dimensional information about solid materials with a resolution of a few nanometres and thus bridges the gap between X-ray and transmission electron microscopic tomography techniques. This contribution

  3. Investigation and optimisation of a plasma cathode electron beam gun for material processing applications

    OpenAIRE

    Del Pozo Rodriguez, Sofia

    2016-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University London. This thesis describes design, development and testing work on a plasma cathode electron beam gun as well as plasma diagnosis experiments and Electron Beam (EB) current measurements carried out with the aim of maximising the power of the EB extracted and optimising the electron beam gun system for material processing applications. The elements which influence EB gun design are described...

  4. Applications of transmission electron microscopy in the materials and mineral sciences

    International Nuclear Information System (INIS)

    Murr, L.E.

    1975-01-01

    Unique capabilities of transmission electron microscopy in characterizing the structure and properties of metals, minerals, and other crystaline materials are illustrated and compared with observations in the scanning electron and field-ion microscopes. Contrast mechanisms involving both mass-thickness and diffraction processes are illustrated, and examples presented of applications of bright and dark-field techiques. Applications of the electron microscope in the investigation of metallurgical and mineralogical problems are outlined with representative examples [pt

  5. Basic mechanisms of radiation effects on electronic materials and devices

    International Nuclear Information System (INIS)

    Winokur, P.S.

    1989-01-01

    Many defense and nuclear reactor systems require complementary metal-oxide semiconductor integrated circuits that are tolerant to high levels of radiation. This radiation can result from space, hostile environments or nuclear reactor and accelerator beam environments. In addition, many techniques used to fabricate today's complex very-large-scale integration circuits expose the circuits to ionizing radiation during the process sequence. Whatever its origin, radiation can cause significant damage to integrated-circuit materials. This damage can lead to circuit performance degradation, logic upset, and even catastrophic circuit failure. This paper provides a brief overview of the basic mechanisms for radiation damage to silicon-based integrated circuits. Primary emphasis is on the effects of total-dose ionizing radiation on metal-oxide-semiconductor (MOS) structures

  6. Potential of Electronic Plastic Waste as a Source of Raw Material and Energy Recovery

    International Nuclear Information System (INIS)

    Norazli Othman; Nor Ezlin Ahmad Basri; Lariyah Mohd Sidek

    2009-01-01

    Nowadays, the production of electronic equipment is one of the fastest growing industrial activities in this world. The increase use of plastic in this sector resulted in an increase of electronic plastic waste. Basically, electronic plastic material contains various chemical elements which act as a flame retardant when electronic equipment is operated. In general, the concept of recycling electronic plastic waste should be considered in order to protect the environment. For this purpose, research has been conducted to different resins of electronic plastic waste to identify the potential of electronic plastic waste as a source of raw material and energy recovery. This study was divided into two part for example determination of physical and chemical characteristics of plastic resins and calculation of heating value for plastic resins based on Dulong formula. Results of this research show that the average calorific value of electronic waste is 30,872.42 kJ/ kg (7,375 kcal/ kg). The emission factor analysis showed that the concentration of emission value that might occur during waste management activities is below the standard set by the Environment Quality Act 1974. Basically, this research shows that electronic plastic waste has the potential to become the source of raw material and energy recovery. (author)

  7. Imaging and elemental mapping of biological specimens with a dual-EDS dedicated scanning transmission electron microscope

    Science.gov (United States)

    Wu, J.S.; Kim, A. M.; Bleher, R.; Myers, B.D.; Marvin, R. G.; Inada, H.; Nakamura, K.; Zhang, X.F.; Roth, E.; Li, S.Y.; Woodruff, T. K.; O'Halloran, T. V.; Dravid, Vinayak P.

    2013-01-01

    A dedicated analytical scanning transmission electron microscope (STEM) with dual energy dispersive spectroscopy (EDS) detectors has been designed for complementary high performance imaging as well as high sensitivity elemental analysis and mapping of biological structures. The performance of this new design, based on a Hitachi HD-2300A model, was evaluated using a variety of biological specimens. With three imaging detectors, both the surface and internal structure of cells can be examined simultaneously. The whole-cell elemental mapping, especially of heavier metal species that have low cross-section for electron energy loss spectroscopy (EELS), can be faithfully obtained. Optimization of STEM imaging conditions is applied to thick sections as well as thin sections of biological cells under low-dose conditions at room- and cryogenic temperatures. Such multimodal capabilities applied to soft/biological structures usher a new era for analytical studies in biological systems. PMID:23500508

  8. Advanced electron microscopy of wide band-gap semiconductor materials

    International Nuclear Information System (INIS)

    Fay, M.W.

    2000-10-01

    The microstructure of GaN layers grown by metal organic vapour phase epitaxy on (0001) sapphire substrates using a novel precursor for deposition of AlN buffer layers has been investigated and compared to layers grown using low temperature GaN buffer layers and state-of-the-art material. It has been shown that the quality of layers grown using the novel precursor is comparable to the state-of-the-art material. TEM analysis has been performed of multiple quantum wells of InGaN grown within GaN epitaxial layers by metal organic vapour phase epitaxy. Elementally sensitive TEM techniques have been used to determine the spatial distribution of In and Ga within these structures. Fluctuations in In sensitive images are observed on the nm-scale. Clear evidence of segregation of In during layer growth has been seen. Models of the In segregation are in good agreement with experimental results. Elementally sensitive techniques have been used to investigate the elemental distributions in TiAl and NiAu contacts to GaN. Annealing of TiAl contacts has been seen to result in the formation of a thin interfacial Ti rich phase, and of N depletion at the surface of the GaN layer to the depth of tens of nm. Annealing NiAu contacts at 700 deg. C was seen to result in the formation of Ga-rich interfacial phases, of both crystalline and amorphous structure. ZnS and ZnCdS layers grown on (001) GaP supplied by the University of Hull have been investigated. ZnS layers were found to contain a high density of inclined stacking faults throughout the layer, originating from the interface with the substrate. Energy sensitive techniques have been used to investigate ZnCdS quantum well structures. The use of a ZnCdS superlattice structure around a ZnCdS quantum well to approximate a reduced barrier was seen to result in less thickness variations than when no barrier was used. (author)

  9. Possibilities of nondestructive determination of fluorine in coal and biological materials by IPAA

    International Nuclear Information System (INIS)

    Randa, Zdenek; Mizera, Jiri; Chvatil, David

    2009-01-01

    The possibilities of nondestructive determination of fluorine in coal and biological materials by instrumental photon activation analysis (IPAA) were studied. The determination was based on counting the non-specific 511 keV annihilation gamma rays of 18 F, a pure positron emitter which is the product of the photonuclear reaction 19 F(γ, n) 18 F. The simultaneous formation of some additional positron emitters, particularly 45 Ti and 34m Cl, is an interfering factor. When using correction standards for Ti and Cl and optimization of the beam energy and irradiation-decay-counting times, fluorine could be determined by IPAA in selected coal and biological samples at the ten ppm level. The feasibility of additional optimization for further improvements of the proposed IPAA procedure are discussed

  10. Exploring matter through photons and neutrons: from biological molecules to designer materials

    International Nuclear Information System (INIS)

    Chidambaram, R.; Hosur, M.V.; Ramanadham, M.; Godwal, B.K.

    2000-01-01

    Understanding structure-property relationships of naturally occurring materials has been the aim of scientific research for centuries. The discovery of short wavelength x-rays and neutrons in the 20th century provided a means of studying molecular structure. The methodology of x-ray and neutron diffraction has been successfully applied to determine structures of molecules across disciplines of physics, chemistry, biology, biochemistry and medicine. Typical applications in physics include study of phase transformations, elasticity measurements, magnetic structure, surface scattering etc. In chemistry, the applications have ranged from routine structure determinations of reaction intermediates or natural products to refinement of quantum chemical parameters of atomic and molecular charge densities. The science of crystallography has had a profound effect on the disciplines of biology and medicine. A whole new discipline and industry was created when the structure of DNA was discovered through x-ray diffraction

  11. Headspace solid-phase microextraction procedures for gas chromatographic analysis of biological fluids and materials.

    Science.gov (United States)

    Mills, G A; Walker, V

    2000-12-01

    Solid-phase microextraction (SPME) is a new solventless sample preparation technique that is finding wide usage. This review provides updated information on headspace SPME with gas chromatographic separation for the extraction and measurement of volatile and semivolatile analytes in biological fluids and materials. Firstly the background to the technique is given in terms of apparatus, fibres used, extraction conditions and derivatisation procedures. Then the different matrices, urine, blood, faeces, breast milk, hair, breath and saliva are considered separately. For each, methods appropriate for the analysis of drugs and metabolites, solvents and chemicals, anaesthetics, pesticides, organometallics and endogenous compounds are reviewed and the main experimental conditions outlined with specific examples. Then finally, the future potential of SPME for the analysis of biological samples in terms of the development of new devices and fibre chemistries and its coupling with high-performance liquid chromatography is discussed.

  12. Development of Standards for NanoSIMS Analyses of Biological Materials

    Energy Technology Data Exchange (ETDEWEB)

    Davission, M L; Weber, P K; Pett-Ridge, J; Singer, S

    2008-07-31

    NanoSIMS is a powerful analytical technique for investigating element distributions at the nanometer scale, but quantifying elemental abundances requires appropriate standards, which are not readily available for biological materials. Standards for trace element analyses have been extensively developed for secondary ion mass spectrometry (SIMS) in the semiconductor industry and in the geological sciences. The three primary approaches for generating standards for SIMS are: (1) ion implantation (2) using previously characterized natural materials, and (3) preparing synthetic substances. Ion implantation is a reliable method for generating trace element standards, but it is expensive, which limits investigation of the analytical issues discussed above. It also requires low background levels of the elements of interest. Finding or making standard materials has the potential to provide more flexibility than ion implantation, but realizing homogeneity at the nano-scale is in itself a significant challenge. In this study, we experiment with all three approaches, but with an emphasis toward synthetic organic polymers in order to reduce costs, increase flexibility, and achieve a wide dynamic concentration range. This emphasis serves to meet the major challenge for biological samples of identifying matrix matched, homogeneous material. Biological samples themselves are typically heterogeneous at the scale of microns to 100s of microns, and therefore they are poor SIMS standards. Therefore, we focused on identifying 'biological-like' materials--either natural or synthetic--that can be used for standards. The primary criterion is that the material be as compositionally similar to biological samples as possible (primarily C, H, O, and N). For natural material we adsorbed organic colloids consisting of peptidoglycan (i.e., amino sugars), activated charcoal, and humic acids. Experiments conducted with Si on peptidoglycan showed low affinity as SiO{sub 2}, yet its

  13. Radiation Damage Studies of Materials and Electronic Devices Using Hadrons

    Energy Technology Data Exchange (ETDEWEB)

    Pellett, David; Baldwin, Andrew; Gallagher, Garratt; Olson, David; Styczinski, Marshall

    2014-05-14

    We have irradiated NdFeB permanent magnet samples from different manufacturers and with differing values of coercivity and remanence using stepped doses of 1 MeV equivalent neutrons up to a fluence of 0:64 1015n=cm2 to evaluate effects on magnetization and B field distributions. The samples with high coercivity, irradiated in open circuit configurations, showed no or minimal effects when compared with unirradiated samples, whereas the lower coercivity magnets suffered significant losses of magnetization and changes in the shapes of their field patterns. One such magnet underwent a fractional magnetization loss of 13.1% after a fluence of 0:59 1015 n=cm2. This demagnetization was not uniform. With increasing fluence, B field scans along the centerlines of the pole faces revealed that the normal component of B decreased more near the midpoint of the scan than near the ends. In addition, a fit to the curve of overall magnetization loss with fluence showed a significant deviation from linearity. The results are discussed in light of other measurements and theory. The high coercivity materials appear suitable for use in accelerator applications subject to irradiation by fast neutrons such as dipoles where the internal demagnetizing field is comparable to or less than that of the open circuit samples tested in this study.

  14. Topological insulators/superconductors: Potential future electronic materials

    International Nuclear Information System (INIS)

    Hor, Y. S.

    2014-01-01

    A new material called topological insulator has been discovered and becomes one of the fastest growing field in condensed matter physics. Topological insulator is a new quantum phase of matter which has Dirac-like conductivity on its surface, but bulk insulator through its interior. It is considered a challenging problem for the surface transport measurements because of dominant internal conductance due to imperfections of the existing crystals of topological insulators. By a proper method, the internal bulk conduction can be suppressed in a topological insulator, and permit the detection of the surface currents which is necessary for future fault-tolerant quantum computing applications. Doped topological insulators have depicted a large variety of bulk physical properties ranging from magnetic to superconducting behaviors. By chemical doping, a TI can change into a bulk superconductor. Nb x Bi 2 Se 3 is shown to be a superconductor with T c ∼ 3.2 K, which could be a potential candidate for a topological superconductor

  15. [Occupational accidents due to exposure to biological material in the multidisciplinary team of the emergency service].

    Science.gov (United States)

    Oliveira, Adriana Cristina; Lopes, Aline Cristine Souza; Paiva, Maria Henriqueta Rocha Siqueira

    2009-09-01

    This transversal, survey-based research was carried out with a multiprofessional emergency care team in Belo Horizonte, between June and December 2006. The study aimed at estimating the incidence of occupational accidents by exposure to biological material, post-accidents conducts and demographic determinant factors. The study applied a structured questionnaire and descriptive analyses, as well as incidence calculations and logistic regression. The incidence of accidents with biological material reached 20.6%, being 40.8% by sharp materials and 49.0% by body fluids; 35.3% of the accidents took place among physicians and 24.0% among nurses. Post-accidents procedures: no medical assessment, 63.3%; under-notification, 81.6%; no conduct, 55.0%; and no serological follow-up, 61.2%. Factors associated with accidents: working time in the institution (Odds Ratio--OR, 2.84; Credible Interval--CI 95%-1.22-6.62); working in advanced support units (OR = 4.18; CI 95%--1.64-10.64); and interaction between working time in the institution and working in Basic Support Unit (OR 0.27; CI 95%--0.07-1.00). In order to reduce accidents, the implementation of post-accident protocols and follow-up, as well as under-notification norms, are suggested.

  16. Biological and Biomimetic Low-Temperature Routes to Materials for Energy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Morse, Daniel E. [Univ. of California, Santa Barbara, CA (United States). Inst. for Collaborative Biotechnologies

    2016-08-29

    New materials are needed to significantly improve the efficiencies of energy harnessing, transduction and storage, yet the synthesis of advanced composites and multi-metallic semiconductors with nanostructures optimized for these functions remains poorly understood and even less well controlled. To help address this need, we proposed three goals: (1) to further investigate the hierarchical structure of the biologically synthesized silica comprising the skeletal spicules of sponges that we discovered, to better resolve the role and mechanism of templating by the hierarchically assembled silicatein protein filament; (2) to extend our molecular and genetic analyses and engineering of silicatein, the self-assembling, structure-directing, silica-synthesizing enzyme we discovered and characterized, to better understand and manipulate the catalysis and templating of semiconductor synthesis,; and (3) to further investigate, scale up and harness the biologically inspired, low-temperature, kinetically controlled catalytic synthesis method we developed (based on the mechanism we discovered in silicatein) to investigate the kinetic control of the structure-function relationships in magnetic materials, and develop new materials for energy applications. The bio-inspired catalytic synthesis method we have developed is low-cost, low temperature, and operates without the use of polluting chemicals. In addition to direct applications for improvement of batteries and fuel cells, the broader impact of this research includes a deeper fundamental understanding of the factors governing kinetically controlled synthesis and its control of the emergent nanostructure and performance of a wide range of nanomaterials for energy applications.

  17. Use of vitamin B12 radioassay in the analysis of biological materials, mainly of foods

    International Nuclear Information System (INIS)

    Kralova, B.; Rauch, P.; Cerna, J.

    1982-01-01

    Vitamin B 12 was determined in biological materials by three basically different methods: microbiological assay with Lactobacillus leichmannii, microbiological assay with Escherichia coli and radioassay. The method with E. coli has a relatively low sensitivity to vitamin B 12 and in some cases of vitamin B 12 determination in microbial materials it can be used only after a separation of the interfering substances by gel chromatography. The procedure is suitable for orientational determinations of vitamin B 12 because it is very little affected by external factors. The assay with L. leichmannii is universal owing to its high specifity and sensitivity to vitamin B 12 . The main disadvantage of the latter procedure depends on the high requirements for a clean atmosphere which can be maintained in laboratories in industrial areas only with difficulties. These limitations do not apply to the quick and sensitive radioassay. The radioassay can be used after a suitable adjustment of the working procedure for large series of analyses of biological materials without any preliminary separational techniques. (author)

  18. The essential role of vibronic interactions in electron pairing in the micro- and macroscopic sized materials

    International Nuclear Information System (INIS)

    Kato, Takashi

    2010-01-01

    Graphical abstract: The electron-phonon interactions destroy the electron pairs formed by Coulomb interactions, and at the same time, form the energy gap by which the electron pairs become stable. - Abstract: In order to discuss how the nondissipative delocalized diamagnetic currents in the microscopic sized materials are closely related to the conventional superconductivity in the macroscopic sized materials, the unified theory, by which various sized superconductivity can be explained, is suggested. It has been believed for a long time that the electron-phonon interactions play an essential role in the attractive electron-electron interactions, as described in the Bardeen-Cooper-Schrieffer (BCS) theory in the conventional superconductivity. However, it is suggested in this paper that the electron-phonon interactions do not play an essential role in the attractive electron-electron interactions but play an essential role in the forming of energy gap by which the electron pairs formed by the attractive Coulomb interactions in the conventional superconducting states become more stable than those in the normal metallic states at low temperatures.

  19. Decacyclene Trianhydride at Functional Interfaces: An Ideal Electron Acceptor Material for Organic Electronics

    DEFF Research Database (Denmark)

    de Oteyza, Dimas G.; García Lastra, Juan Maria; Toma, Francesca M.

    2016-01-01

    , respectively, reveal that electron transfer from substrate to surface sets in. Density functional theory calculations confirm our experimental findings and provide an understanding not only of the photoemission and X-ray absorption spectral features of this promising organic semiconductor but also...

  20. Spatiotemporal Observation of Electron-Impact Dynamics in Photovoltaic Materials Using 4D Electron Microscopy

    KAUST Repository

    Shaheen, Basamat; Sun, Jingya; Yang, Ding-Shyue; Mohammed, Omar F.

    2017-01-01

    information can be obtained using the one-of-a-kind methodology of scanning ultrafast electron microscopy (S-UEM). Here, we address the fundamental issue of how the thickness of the absorber layer may significantly affect the charge carrier dynamics