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Sample records for biologically tunable material

  1. Tunable structural color in organisms and photonic materials for design of bioinspired materials

    International Nuclear Information System (INIS)

    Fudouzi, Hiroshi

    2011-01-01

    In this paper, the key topics of tunable structural color in biology and material science are overviewed. Color in biology is considered for selected groups of tropical fish, octopus, squid and beetle. It is caused by nanoplates in iridophores and varies with their spacing, tilting angle and refractive index. These examples may provide valuable hints for the bioinspired design of photonic materials. 1D multilayer films and 3D colloidal crystals with tunable structural color are overviewed from the viewpoint of advanced materials. The tunability of structural color by swelling and strain is demonstrated on an example of opal composites. (topical review)

  2. Tunable structural color in organisms and photonic materials for design of bioinspired materials

    Directory of Open Access Journals (Sweden)

    Hiroshi Fudouzi

    2011-01-01

    Full Text Available In this paper, the key topics of tunable structural color in biology and material science are overviewed. Color in biology is considered for selected groups of tropical fish, octopus, squid and beetle. It is caused by nanoplates in iridophores and varies with their spacing, tilting angle and refractive index. These examples may provide valuable hints for the bioinspired design of photonic materials. 1D multilayer films and 3D colloidal crystals with tunable structural color are overviewed from the viewpoint of advanced materials. The tunability of structural color by swelling and strain is demonstrated on an example of opal composites.

  3. Tunable structural color in organisms and photonic materials for design of bioinspired materials

    Science.gov (United States)

    Fudouzi, Hiroshi

    2011-01-01

    In this paper, the key topics of tunable structural color in biology and material science are overviewed. Color in biology is considered for selected groups of tropical fish, octopus, squid and beetle. It is caused by nanoplates in iridophores and varies with their spacing, tilting angle and refractive index. These examples may provide valuable hints for the bioinspired design of photonic materials. 1D multilayer films and 3D colloidal crystals with tunable structural color are overviewed from the viewpoint of advanced materials. The tunability of structural color by swelling and strain is demonstrated on an example of opal composites. PMID:27877454

  4. Tunable promoters in systems biology

    DEFF Research Database (Denmark)

    Mijakovic, Ivan; Petranovic, Dina; Jensen, Peter Ruhdal

    2005-01-01

    The construction of synthetic promoter libraries has represented a major breakthrough in systems biology, enabling the subtle tuning of enzyme activities. A number of tools are now available that allow the modulation of gene expression and the detection of changes in expression patterns. But, how...

  5. Hybrid nanostructured materials with tunable magnetic characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Martínez, Nubia E.; Garza-Navarro, M. A., E-mail: marco.garzanr@uanl.edu.mx; García-Gutiérrez, Domingo; González-González, Virgilio A.; Torres-Castro, Alejandro; Ortiz-Méndez, U. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica (Mexico)

    2014-12-15

    We report on the development of hybrid nanostructured materials (HNM) based on spinel-metal-oxide nanoparticles (SMON) stabilized in carboxymethyl-cellulose (CMC)/cetyltrimethyl-ammonium-bromide (CTAB) templates, with tunable magnetic characteristics. These HNM were synthesized using a one-pot chemical approach to obtain CMC/CTAB templates with controllable size and morphology, where the SMON could be densely arranged. The synthesized HNM were characterized by transmission electron microscopy and its related techniques, such as bright field (BF) and Z-contrast (HAADF-STEM) imaging, and selected area electron diffraction, as well as static magnetic measuring. Experimental evidence suggests that the morphology and size of the CMC/CTAB templates are highly dependent on the weight ratio of CTAB:SMON, as well as the hydration days of the CMC that is used for the synthesis of the HNM. Controlling these parameters allows modifying the density of the SMON arrangement in the CMC/CTAB templates. Moreover, magnetic features such as remanence, coercivity, and blocking/de-blocking processes of the particles’ magnetic moments are highly dependent on the interactions among the SMON assembled in the templates. Hence, the magnetic characteristics of HNM can be modulated or tuned by controlling the manner the SMON are arranged within the CMC/CTAB templates.

  6. Tunable promoters in synthetic and systems biology

    DEFF Research Database (Denmark)

    Dehli, Tore; Solem, Christian; Jensen, Peter Ruhdal

    2012-01-01

    in synthetic biology. A number of tools exist to manipulate the steps in between gene sequence and functional protein in living cells, but out of these the most straight-forward approach is to alter the gene expression level by manipulating the promoter sequence. Some of the promoter tuning tools available......Synthetic and systems biologists need standardized, modular and orthogonal tools yielding predictable functions in vivo. In systems biology such tools are needed to quantitatively analyze the behavior of biological systems while the efficient engineering of artificial gene networks is central...... for accomplishing such altered gene expression levels are discussed here along with examples of their use, and ideas for new tools are described. The road ahead looks very promising for synthetic and systems biologists as tools to achieve just about anything in terms of tuning and timing multiple gene expression...

  7. [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.

  8. 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.)

  9. 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...

  10. Electrically tunable polarizer based on 2D orthorhombic ferrovalley materials

    Science.gov (United States)

    Shen, Xin-Wei; Tong, Wen-Yi; Gong, Shi-Jing; Duan, Chun-Gang

    2018-03-01

    The concept of ferrovalley materials has been proposed very recently. The existence of spontaneous valley polarization, resulting from ferromagnetism, in such hexagonal 2D materials makes nonvolatile valleytronic applications realizable. Here, we introduce a new member of ferrovalley family with orthorhombic lattice, i.e. monolayer group-IV monochalcogenides (GIVMs), in which the intrinsic valley polarization originates from ferroelectricity, instead of ferromagnetism. Combining the group theory analysis and first-principles calculations, we demonstrate that, different from the valley-selective circular dichroism in hexagonal lattice, linearly polarized optical selectivity for valleys exists in the new type of ferrovalley materials. On account of the distinctive property, a prototype of electrically tunable polarizer is realized. In the ferrovalley-based polarizer, a laser beam can be optionally polarized in x- or y-direction, depending on the ferrovalley state controlled by external electric fields. Such a device can be further optimized to emit circularly polarized radiation with specific chirality and to realize the tunability for operating wavelength. Therefore, we show that 2D orthorhombic ferrovalley materials are the promising candidates to provide an advantageous platform to realize the polarizer driven by electric means, which is of great importance in extending the practical applications of valleytronics.

  11. 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.

  12. Tunable states of interlayer cations in two-dimensional materials

    International Nuclear Information System (INIS)

    Sato, K.; Numata, K.; Dai, W.; Hunger, M.

    2014-01-01

    The local state of cations inside the Ångstrom-scale interlayer spaces is one of the controlling factors for designing sophisticated two-dimensional (2D) materials consisting of 2D nanosheets. In the present work, the molecular mechanism on how the interlayer cation states are induced by the local structures of the 2D nanosheets is highlighted. For this purpose, the local states of Na cations in inorganic 2D materials, in which the compositional fluctuations of a few percent are introduced in the tetrahedral and octahedral units of the 2D nanosheets, were systematically studied by means of 23 Na magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) and 23 Na multiple-quantum MAS (MQMAS) NMR spectroscopy. In contrast with an uniform distribution of Na cations expected so far, various well-defined cation states sensitive to the local structures of the 2D nanosheets were identified. The tunability of the interlayer cation states along with the local structure of the 2D nanosheets, as the smallest structural unit of the 2D material, is discussed

  13. Tunable states of interlayer cations in two-dimensional materials

    Energy Technology Data Exchange (ETDEWEB)

    Sato, K.; Numata, K. [Department of Environmental Sciences, Tokyo Gakugei University, Koganei, Tokyo 184-8501 (Japan); Dai, W. [Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin 300071 (China); Hunger, M. [Institute of Chemical Technology, University of Stuttgart, 70550 Stuttgart (Germany)

    2014-03-31

    The local state of cations inside the Ångstrom-scale interlayer spaces is one of the controlling factors for designing sophisticated two-dimensional (2D) materials consisting of 2D nanosheets. In the present work, the molecular mechanism on how the interlayer cation states are induced by the local structures of the 2D nanosheets is highlighted. For this purpose, the local states of Na cations in inorganic 2D materials, in which the compositional fluctuations of a few percent are introduced in the tetrahedral and octahedral units of the 2D nanosheets, were systematically studied by means of {sup 23}Na magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) and {sup 23}Na multiple-quantum MAS (MQMAS) NMR spectroscopy. In contrast with an uniform distribution of Na cations expected so far, various well-defined cation states sensitive to the local structures of the 2D nanosheets were identified. The tunability of the interlayer cation states along with the local structure of the 2D nanosheets, as the smallest structural unit of the 2D material, is discussed.

  14. 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.

  15. 3D Printing of Materials with Tunable Failure via Bioinspired Mechanical Gradients.

    Science.gov (United States)

    Kokkinis, Dimitri; Bouville, Florian; Studart, André R

    2018-05-01

    Mechanical gradients are useful to reduce strain mismatches in heterogeneous materials and thus prevent premature failure of devices in a wide range of applications. While complex graded designs are a hallmark of biological materials, gradients in manmade materials are often limited to 1D profiles due to the lack of adequate fabrication tools. Here, a multimaterial 3D-printing platform is developed to fabricate elastomer gradients spanning three orders of magnitude in elastic modulus and used to investigate the role of various bioinspired gradient designs on the local and global mechanical behavior of synthetic materials. The digital image correlation data and finite element modeling indicate that gradients can be effectively used to manipulate the stress state and thus circumvent the weakening effect of defect-rich interfaces or program the failure behavior of heterogeneous materials. Implementing this concept in materials with bioinspired designs can potentially lead to defect-tolerant structures and to materials whose tunable failure facilitates repair of biomedical implants, stretchable electronics, or soft robotics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Non-equilibrium dissipative supramolecular materials with a tunable lifetime

    Science.gov (United States)

    Tena-Solsona, Marta; Rieß, Benedikt; Grötsch, Raphael K.; Löhrer, Franziska C.; Wanzke, Caren; Käsdorf, Benjamin; Bausch, Andreas R.; Müller-Buschbaum, Peter; Lieleg, Oliver; Boekhoven, Job

    2017-07-01

    Many biological materials exist in non-equilibrium states driven by the irreversible consumption of high-energy molecules like ATP or GTP. These energy-dissipating structures are governed by kinetics and are thus endowed with unique properties including spatiotemporal control over their presence. Here we show man-made equivalents of materials driven by the consumption of high-energy molecules and explore their unique properties. A chemical reaction network converts dicarboxylates into metastable anhydrides driven by the irreversible consumption of carbodiimide fuels. The anhydrides hydrolyse rapidly to the original dicarboxylates and are designed to assemble into hydrophobic colloids, hydrogels or inks. The spatiotemporal control over the formation and degradation of materials allows for the development of colloids that release hydrophobic contents in a predictable fashion, temporary self-erasing inks and transient hydrogels. Moreover, we show that each material can be re-used for several cycles.

  17. 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.

  18. 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...

  19. Tunable multichannel filter in photonic crystal heterostructure containing permeability-negative materials

    International Nuclear Information System (INIS)

    Hu Xiaoyong; Liu Zheng; Gong Qihuang

    2008-01-01

    A tunable multichannel filter is demonstrated theoretically based on a one-dimensional photonic crystal heterostructure containing permeability-negative material. The filtering properties of the photonic crystal filter, including the channel number and frequency, can be tuned by adjusting the structure parameters or by a pump laser. The angular response of the photonic crystal filter and the influences of the losses on the filtering properties are also analyzed

  20. Tunable multichannel filter in photonic crystal heterostructure containing permeability-negative materials

    Energy Technology Data Exchange (ETDEWEB)

    Hu Xiaoyong [State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871 (China)], E-mail: xiaoyonghu@pku.edu.cn; Liu Zheng [State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871 (China); Gong Qihuang [State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871 (China)], E-mail: qhgong@pku.edu.cn

    2008-01-14

    A tunable multichannel filter is demonstrated theoretically based on a one-dimensional photonic crystal heterostructure containing permeability-negative material. The filtering properties of the photonic crystal filter, including the channel number and frequency, can be tuned by adjusting the structure parameters or by a pump laser. The angular response of the photonic crystal filter and the influences of the losses on the filtering properties are also analyzed.

  1. Evaluation of the Biological Effects of Externally Tunable, Hydrogel Encapsulated Quantum Dot Nanospheres in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Somesree GhoshMitra

    2011-08-01

    Full Text Available Quantum Dots (QDs have become an interesting subject of study for labeling and drug delivery in biomedical research due to their unique responses to external stimuli. In this paper, the biological effects of a novel hydrogel based QD nano-structure on E. coli bacteria are presented. The experimental evidence reveals that cadmium telluride (CdTe QDs that are encapsulated inside biocompatible polymeric shells have reduced or negligible toxicity to this model cell system, even when exposed at higher dosages. Furthermore, a preliminary gene expression study indicates that QD-hydrogel nanospheres do not inhibit the Green Fluorescent Protein (GFP gene expression. As the biocompatible and externally tunable polymer shells possess the capability to control the QD packing density at nanometer scales, the resulting luminescence efficiency of the nanostructures, besides reducing the cytotoxic potential, may be suitable for various biomedical applications.

  2. Voltage tunability of thermal conductivity in ferroelectric materials

    Science.gov (United States)

    Ihlefeld, Jon; Hopkins, Patrick Edward

    2016-02-09

    A method to control thermal energy transport uses mobile coherent interfaces in nanoscale ferroelectric films to scatter phonons. The thermal conductivity can be actively tuned, simply by applying an electrical potential across the ferroelectric material and thereby altering the density of these coherent boundaries to directly impact thermal transport at room temperature and above. The invention eliminates the necessity of using moving components or poor efficiency methods to control heat transfer, enabling a means of thermal energy control at the micro- and nano-scales.

  3. 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

  4. Tunable polymeric sorbent materials for fractionation of model naphthenates.

    Science.gov (United States)

    Mohamed, Mohamed H; Wilson, Lee D; Headley, John V

    2013-04-04

    The sorption properties are reported for several examples of single-component carboxylic acids representing naphthenic acids (NAs) with β-cyclodextrin (β-CD) based polyurethane sorbents. Seven single-component examples of NAs were chosen with variable z values, carbon number, and chemical structure as follows: 2-hexyldecanoic acid (z = 0 and C = 16; S1), n-caprylic acid (z = 0 and C = 8; S2), trans-4-pentylcyclohexanecarboxylic acid (z = -2 and C = 12; S3), 4-methylcyclohexanecarboxylic acid (z = -2 and C = 8; S4), dicyclohexylacetic acid (z = -4; C = 14; S5), 4-pentylbicyclo[2.2.2]octane-1-carboxylic acid (z = -4; C = 14; S6), and lithocholic acid (z = -6; C = 24; S7). The copolymer sorbents were synthesized at three relative β-CD:diisocyanate mole ratios (i.e., 1:1, 1:2, and 1:3) using 4,4'-dicyclohexylmethane diisocyanate (CDI) and 4,4'-diphenylmethane diisocyanate (MDI). The sorption properties of the copolymer sorbents were characterized using equilibrium sorption isotherms in aqueous solution at pH 9.00 with electrospray ionization mass spectrometry. The equilibrium fraction of the unbound carboxylate anions was monitored in the aqueous phase. The sorption properties of the copolymer sorbents (i.e., Qm) were obtained from the Sips isotherm model. The Qm values generally decrease as the number of accessible β-CD inclusion sites in the copolymer framework decreases. The chemical structure of the adsorbates played an important role in their relative uptake, as evidenced by the adsorbate lipophilic surface area (LSA) and the involvement of hydrophobic effects. The copolymers exhibit molecular selective sorption of the single-component carboxylates in mixtures which suggests their application as sorbents for fractionation of mixtures of NAs. By comparison, granular activated carbon (GAC) and chitosan sorbents did not exhibit any significant molecular selective sorption relative to the copolymer materials; however, evidence of variable sorption capacity was

  5. Tunable elastic parity-time symmetric structure based on the shunted piezoelectric materials

    Science.gov (United States)

    Hou, Zhilin; Assouar, Badreddine

    2018-02-01

    We theoretically and numerically report on the tunable elastic Parity-Time (PT) symmetric structure based on shunted piezoelectric units. We show that the elastic loss and gain can be archived in piezoelectric materials when they are shunted by external circuits containing positive and negative resistances. We present and discuss, as an example, the strongly dependent relationship between the exceptional points of a three-layered system and the impedance of their external shunted circuit. The achieved results evidence that the PT symmetric structures based on this proposed concept can actively be tuned without any change of their geometric configurations.

  6. Biologically Safe Poly(l-lactic acid) Blends with Tunable Degradation Rate: Microstructure, Degradation Mechanism, and Mechanical Properties.

    Science.gov (United States)

    Oyama, Hideko T; Tanishima, Daisuke; Ogawa, Ryohei

    2017-04-10

    Although poly(l-lactic acid) (PLLA) is reputed to be biodegradable in the human body, its hydrophobic nature lets it persist for ca. 5.5 years. This study demonstrates that biologically safe lactide copolymers, poly(aspartic acid-co-l-lactide) (PAL) and poly(malic acid-co-l-lactide) (PML), dispersed in the PLLA function as detonators (triggers) for its hydrolytic degradation under physiological conditions. The copolymers significantly enhance hydrolysis, and consequently, the degradation rate of PLLA becomes easily tunable by controlling the amounts of PAL and PML. The present study elucidates the effects of uniaxial drawing on the structural development, mechanical properties, and hydrolytic degradation under physiological conditions of PLLA blend films. At initial degradation stages, the mass loss was not affected by uniaxial drawing; however, at late degradation stages, less developed crystals as well as amorphous chains were degradable at low draw ratio (DR), whereas not only highly developed crystals but also the oriented amorphous chains became insensitive to hydrolysis at high DR. Our work provides important molecular level results that demonstrate that biodegradable materials can have superb mechanical properties and also disappear in a required time under physiological conditions.

  7. 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

  8. 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.

  9. 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

  10. 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...

  11. 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.

  12. Elucidation of Peptide-Directed Palladium Surface Structure for Biologically Tunable Nanocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Bedford, Nicholas M.; Ramezani-Dakhel, Hadi; Slocik, Joseph M.; Briggs, Beverly D.; Ren, Yang; Frenkel, Anatoly I.; Petkov, Valeri; Heinz, Hendrik; Naik, Rajesh R.; Knecht, Mark R.

    2015-05-01

    Peptide-enabled synthesis of inorganic nanostructures represents an avenue to access catalytic materials with tunable and optimized properties. This is achieved via peptide complexity and programmability that is missing in traditional ligands for catalytic nanomaterials. Unfortunately, there is limited information available to correlate peptide sequence to particle structure and catalytic activity to date. As such, the application of peptide-enabled nanocatalysts remains limited to trial and error approaches. In this paper, a hybrid experimental and computational approach is introduced to systematically elucidate biomolecule-dependent structure/function relationships for peptide-capped Pd nanocatalysts. Synchrotron X-ray techniques were used to uncover substantial particle surface structural disorder, which was dependent upon the amino acid sequence of the peptide capping ligand. Nanocatalyst configurations were then determined directly from experimental data using reverse Monte Carlo methods and further refined using molecular dynamics simulation, obtaining thermodynamically stable peptide-Pd nanoparticle configurations. Sequence-dependent catalytic property differences for C-C coupling and olefin hydrogenation were then eluddated by identification of the catalytic active sites at the atomic level and quantitative prediction of relative reaction rates. This hybrid methodology provides a clear route to determine peptide-dependent structure/function relationships, enabling the generation of guidelines for catalyst design through rational tailoring of peptide sequences

  13. Fullerene-based low-density superhard materials with tunable bandgaps

    Science.gov (United States)

    Cao, Ai-Hua; Zhao, Wen-Juan; Gan, Li-Hua

    2018-06-01

    Four carbon allotropes built from tetrahedral symmetrical fullerenes C28 and C40 are predicted to be superhard materials with mass density around that of water, and all of them are porous semiconductors. Both the bandgaps and hardness decrease with increasing ratio of sp2 hybridized carbon atoms. The mechanical and thermodynamic stabilities of C28- and C40-based allotropes at zero pressure are confirmed by a variety of state-of-the-art theoretical calculations. The evolution trend of bandgap found here suggests that one can obtain low-density hard materials with tunable bandgaps by substituting the carbon atom in diamond with different Td-symmetrical non-IPR fullerene Cn.

  14. Thermally tunable broadband omnidirectional and polarization-independent super absorber using phase change material VO2

    Directory of Open Access Journals (Sweden)

    Zhejun Liu

    Full Text Available In this letter, we numerically demonstrate a thermally tunable super absorber by using phase change material VO2 as absorbing layer in metal-insulator-metal structure. An omnidirectional super absorption at λ=2.56μm can be realized by heating the patterned grating VO2 film due to magnetic resonance mechanism. Furthermore, a broadband super absorption higher than 0.8 in the entire 1.6μm–4μm region is achieved when VO2 film is patterned chessboard structure and transformed to metal phase beyond transition temperature. This broadband super absorption can be fulfilled in a wide range of incident angle (0°–70° and under all polarization conditions. Keywords: Phase change material, Metal-insulator-metal, Super absorption, Magnetic resonance

  15. Tunable ferrites as environmentally friendly materials for energy-efficient processes

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Serrano, Inmaculada; Arillo, Maria Angeles; Lopez, Maria Luisa; Veiga, Maria Luisa; Pico, Carlos [Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid (Spain)

    2011-11-23

    Novel materials and methods of synthesis in the field of energy conversion and economy are reported. The main goal is to prepare and characterize Li{sub (4-x)}Mn{sub (5-2x)}Fe{sub 3x}O{sub 12} compounds. These compounds crystallize in a spinel-type structure, AB{sub 2}O{sub 4}, in which the cationic location in the A and B sublattices drives the potential application of these materials in two current prominent research fields: magnetic refrigeration and lithium batteries. This solid solution is revealed as a tunable system that nicely permits a specific response to be highlighted, depending on the composition and particle size: the magnetocaloric effect or active electrochemical behavior. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. 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...

  17. 3D printing of an interpenetrating network hydrogel material with tunable viscoelastic properties.

    Science.gov (United States)

    Bootsma, Katherine; Fitzgerald, Martha M; Free, Brandon; Dimbath, Elizabeth; Conjerti, Joe; Reese, Greg; Konkolewicz, Dominik; Berberich, Jason A; Sparks, Jessica L

    2017-06-01

    Interpenetrating network (IPN) hydrogel materials are recognized for their unique mechanical properties. While IPN elasticity and toughness properties have been explored in previous studies, the factors that impact the time-dependent stress relaxation behavior of IPN materials are not well understood. Time-dependent (i.e. viscoelastic) mechanical behavior is a critical design parameter in the development of materials for a variety of applications, such as medical simulation devices, flexible substrate materials, cellular mechanobiology substrates, or regenerative medicine applications. This study reports a novel technique for 3D printing alginate-polyacrylamide IPN gels with tunable elastic and viscoelastic properties. The viscoelastic stress relaxation behavior of the 3D printed alginate-polyacrylamide IPN hydrogels was influenced most strongly by varying the concentration of the acrylamide cross-linker (MBAA), while the elastic modulus was affected most by varying the concentration of total monomer material. The material properties of our 3D printed IPN constructs were consistent with those reported in the biomechanics literature for soft tissues such as skeletal muscle, cardiac muscle, skin and subcutaneous tissue. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. 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.

  19. 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.

  20. 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.)

  1. 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

  2. Tunable M-channel filter based on Thue-Morse heterostructures containing meta materials

    Directory of Open Access Journals (Sweden)

    H Pashaei Adl

    2015-01-01

    Full Text Available In this paper the tunable M-channel filters based on Thue-Morse heterostructures consisting of single -negative materials has been studied. The results showed that the number of resonance modes inside the zero- gap increases as the number of heterogenous interface, M, increases. The number of resonance modes inside the zero- gap is equal to that of heterogenous interface M, and it can be used as M channels filter. This result provides a feasible method to adjust the channel number of multiple-channel filters. When losses are involved, the results showed that the electric fields of the resonance modes decay largely with the increase of the number of heterogenous interface and damping factors. Besides, the relationship between the quality factor of multiple-channel filters and the number of heterogenous interface M is linear, and the quality factor of multiple-channel filters decreases with the increase of the damping factor. These results provide feasible methods to adjust the quality factor of multiple-channel filters

  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. 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

  7. Utilizing stretch-tunable thermochromic elastomeric opal films as novel reversible switchable photonic materials.

    Science.gov (United States)

    Schäfer, Christian G; Lederle, Christina; Zentel, Kristina; Stühn, Bernd; Gallei, Markus

    2014-11-01

    In this work, the preparation of highly thermoresponsive and fully reversible stretch-tunable elastomeric opal films featuring switchable structural colors is reported. Novel particle architectures based on poly(diethylene glycol methylether methacrylate-co-ethyl acrylate) (PDEGMEMA-co-PEA) as shell polymer are synthesized via seeded and stepwise emulsion polymerization protocols. The use of DEGMEMA as comonomer and herein established synthetic strategies leads to monodisperse soft shell particles, which can be directly processed to opal films by using the feasible melt-shear organization technique. Subsequent UV crosslinking strategies open access to mechanically stable and homogeneous elastomeric opal films. The structural colors of the opal films feature mechano- and thermoresponsiveness, which is found to be fully reversible. Optical characterization shows that the combination of both stimuli provokes a photonic bandgap shift of more than 50 nm from 560 nm in the stretched state to 611 nm in the fully swollen state. In addition, versatile colorful patterns onto the colloidal crystal structure are produced by spatial UV-induced crosslinking by using a photomask. This facile approach enables the generation of spatially cross-linked switchable opal films with fascinating optical properties. Herein described strategies for the preparation of PDEGMEMA-containing colloidal architectures, application of the melt-shear ordering technique, and patterned crosslinking of the final opal films open access to novel stimuli-responsive colloidal crystal films, which are expected to be promising materials in the field of security and sensing applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Impact of the electrode material and shape on performance of intrinsically tunable ferroelectric FBARs.

    Science.gov (United States)

    Vorobiev, Andrei; Gevorgian, Spartak

    2014-05-01

    Experiment-based analysis of losses in tunable ferroelectric xBiFeO3-(1-x)BaTiO3 (BF-BT) film bulk acoustic wave resonators (FBARs) is reported. The Q-factors, effective coupling coefficients, and tunabilities are considered as functions of surface roughness of the ferroelectric film, the acoustic impedance and shape of the electrodes/interconnecting strips, leakage of acoustic waves into the substrate via Bragg reflector, and the relative thicknesses of the electrodes and ferroelectric film. Compared with Al, the high acoustic impedance of Pt electrodes provides higher Q-factor, coupling coefficient, and tunability. However, using Pt in the interconnecting strips results in reduction of the Q-factor.

  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. 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.

  11. Spectroscopic properties of a novel near-infrared tunable laser material Ni:MgGa2O4

    International Nuclear Information System (INIS)

    Suzuki, Takenobu; Senthil Murugan, Ganapathy; Ohishi, Yasutake

    2005-01-01

    An intense emission band from Ni 2+ in MgGa 2 O 4 spinel in the range of 1.1-1.6μm was observed at room temperature. The emission band could be assigned to the downward d-d transition of T2g3->A2g3 of Ni 2+ ions in octahedral sites. The lifetime of the emission was more than 1.6ms from 5 to 300K. This material has potential as a near-infrared tunable-laser host

  12. Tunable geometry of bacterial inclusion bodies as substrate materials for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    GarcIa-Fruitos, Elena; Seras-Franzoso, JoaquIn; Vazquez, Esther; Villaverde, Antonio [CIBER en BioingenierIa, Biomateriales y Nanomedicina, Bellaterra, 08193 Barcelona (Spain); Institut de Biotecnologia i de Biomedicina and Departament de Genetica i de Microbiologia, Universitat Autonoma de Barcelona, 08193 Bellaterra (Cerdanyola del Valles), Barcelona (Spain)

    2010-05-21

    A spectrum of materials for biomedical applications is produced in bacteria, and some of them, such as metals or polyhydroxyalkanoates, are straightforwardly obtained as particulate entities. We have explored the biofabrication process of bacterial inclusion bodies, particulate proteinaceous materials (ranging from 50 to 500 nm in diameter) recently recognized as suitable for surface topographical modification and tissue engineering. Inclusion bodies have been widely described as spherical or pseudo-spherical particles with only minor morphological variability, mostly restricted to their size. Here we have identified a cellular gene in Escherichia coli (clpP) that controls the in vivo fabrication process of inclusion bodies. In the absence of the encoded protease, the dynamics of protein deposition is perturbed, resulting in unusual tear-shaped particles with enhanced surface-volume ratios. This fact modifies the ability of inclusion bodies to promote mammalian cell attachment and differentiation upon surface decoration. The implications of the genetic control of inclusion body geometry are discussed in the context of their biological fabrication and regarding the biomedical potential of these protein clusters in regenerative medicine.

  13. Tunable geometry of bacterial inclusion bodies as substrate materials for tissue engineering

    International Nuclear Information System (INIS)

    GarcIa-Fruitos, Elena; Seras-Franzoso, JoaquIn; Vazquez, Esther; Villaverde, Antonio

    2010-01-01

    A spectrum of materials for biomedical applications is produced in bacteria, and some of them, such as metals or polyhydroxyalkanoates, are straightforwardly obtained as particulate entities. We have explored the biofabrication process of bacterial inclusion bodies, particulate proteinaceous materials (ranging from 50 to 500 nm in diameter) recently recognized as suitable for surface topographical modification and tissue engineering. Inclusion bodies have been widely described as spherical or pseudo-spherical particles with only minor morphological variability, mostly restricted to their size. Here we have identified a cellular gene in Escherichia coli (clpP) that controls the in vivo fabrication process of inclusion bodies. In the absence of the encoded protease, the dynamics of protein deposition is perturbed, resulting in unusual tear-shaped particles with enhanced surface-volume ratios. This fact modifies the ability of inclusion bodies to promote mammalian cell attachment and differentiation upon surface decoration. The implications of the genetic control of inclusion body geometry are discussed in the context of their biological fabrication and regarding the biomedical potential of these protein clusters in regenerative medicine.

  14. 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.

  15. [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.

  16. 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.

  17. 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

  18. Tunable micro-optics

    CERN Document Server

    Duppé, Claudia

    2015-01-01

    Presenting state-of-the-art research into the dynamic field of tunable micro-optics, this is the first book to provide a comprehensive survey covering a varied range of topics including novel materials, actuation concepts and new imaging systems in optics. Internationally renowned researchers present a diverse range of chapters on cutting-edge materials, devices and subsystems, including soft matter, artificial muscles, tunable lenses and apertures, photonic crystals, and complete tunable imagers. Special contributions also provide in-depth treatment of micro-optical characterisation, scanners, and the use of natural eye models as inspiration for new concepts in advanced optics. With applications extending from medical diagnosis to fibre telecommunications, Tunable Micro-optics equips readers with a solid understanding of the broader technical context through its interdisciplinary approach to the realisation of new types of optical systems. This is an essential resource for engineers in industry and academia,...

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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 ...

  4. 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.

  5. 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

  6. 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.)

  7. 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.

  8. Photochemistry of Fe(Iii)-Carboxylates in Polysaccharide-Based Materials with Tunable Mechanical Properties

    Science.gov (United States)

    Giammanco, Giuseppe E.

    We present the formulation and study of light-responsive materials based on carboxylate-containing polysaccharides. The functional groups in these natural polymers allow for strong interactions with transition metal ions such as Fe(III). The known photochemistry of hydroxycarboxylic acids in natural waters inspired us in exploring the visible light induced photochemistry of the carboxylates in these polysaccharides when coordinated to Fe(III) ions. Described in this dissertation are the design and characterization of the Fe(III)-polysaccharide materials, specifically the mechanistic aspects of the photochemistry and the effects that these reactions have on the structure of the polymer materials. We present a study of the quantitative photochemistry of different polysaccharide systems, where the presence of uronic acids was important for the photoreaction to take place. Alginate (Alg), pectate (Pec), hyaluronic acid (Hya), xanthan gum (Xan), and a polysaccharide extracted from the Noni fruit (NoniPs), were among the natural uronic acid-containing polysaccharide (UCPS) systems we analyzed. Potato starch, lacking of uronate groups, did not present any photochemistry in the presence of Fe(III); however, we were able to induce a photochemical response in this polysaccharide upon chemical manipulation of its functional groups. Important structure-function relationships were drawn from this study. The uronate moiety present in these polysaccharides is then envisioned as a tool to induce response to light in a variety of materials. Following this approach, we report the formulation of materials for controlled drug release, able to encapsulate and release different drug models only upon illumination with visible light. Furthermore, hybrid hydrogels were prepared from UPCS and non-responsive polymers. Different properties of these materials could be tuned by controlling the irradiation time, intensity and location. These hybrid gels were evaluated as scaffolds for tissue

  9. Multi-functionalized side-chain supramolecular polymers: A methodology towards tunable functional materials

    Science.gov (United States)

    Nair, Kamlesh Prabhakaran

    Even as we see a significant growth in the field of supramolecular polymers in the last ten years, multi-functionalized systems have been scarcely studied. Noncovalent multi-functionalization provides unique advantages such as rapid materials optimization via reversible functionalization as well as for the tuning of materials properties by exploiting the differences in the nature of these reversible interactions. This thesis involves the design principles, synthesis & methodology of supramolecular side-chain multi-functionalized polymers. The combination of a functionally tolerant & controlled polymerization technique such as ROMP with multiple noncovalent interactions such as hydrogen bonding, metal coordination and ionic interactions has been successfully used to synthesize these polymers. Furthermore, the orthogonality between the above interactions in block/random copolymers has been studied in detail. It has been found that the studied interactions were orthogonal to each other. To validate the viability of this methodology using multiple orthogonal interactions towards materials design noncovalent crosslinking of polymers has been used as a potential application. Three classes of networks have been studied: complementary multiple hydrogen bonded networks, metal crosslinked networks, & multi-functionalized hydrogen bonded and metal coordinated networks. The first room temperature decrosslinking by exclusive complementary hydrogen bonded interactions has been successfully achieved. Furthermore network properties have been successfully tuned by varying the network micro-structure which in turn was tuned by the hydrogen bonding motifs used for inter-chain crosslinking. By combining two different noncovalent interactions used for inter-chain crosslinking, it was possible to make multi-functionalized materials whose properties could be controlled by varying the crosslinking strategy. Hence by employing multi-functionalization methodology, important materials

  10. 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.

  11. 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.

  12. 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)

  13. 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.)

  14. 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

  15. 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.

  16. 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

  17. 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

  18. 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 ...

  19. 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 ...

  20. Tunable microwave absorbing nano-material for X-band applications

    International Nuclear Information System (INIS)

    Sadiq, Imran; Naseem, Shahzad; Ashiq, Muhammad Naeem; Khan, M.A.; Niaz, Shanawer; Rana, M.U.

    2016-01-01

    The effect of rare earth elements substitution in Sr_1_._9_6RE_0_._0_4Co_2Fe_2_7_._8_0Mn_0_._2O_4_6 (RE=Ce, Gd, Nd, La and Sm) X-type hexagonal ferrites prepared by using sol gel autocombustion method was studied. The XRD and FTIR analysis show the single phase of the prepared material. The lattice constants a (Å) and c (Å) varies with the additives. The particle size measured by Scherer formula for all the samples varies in the range of 54–100 nm and confirmed by the TEM analysis. The average grain size measured by SEM analysis lies in the range of 0.672–1.01 µm for all the samples. The Gd-substituted ferrite has higher value of coercivity (526.06 G) among all the samples which could be a good material for longitudinal recording media. The results also indicate that the Gd-substituted sample has maximum reflection loss of −25.2 dB at 11.878 GHz, can exhibit the best microwave absorption properties among all the substituted samples. Furthermore, the minimum value of reflection loss shifts towards the lower and higher frequencies with the substitution of rare earth elements which confirms that the microwave absorption properties can be tuned with the substitution of rare earth elements in pure ferrites. The peak value of attenuation constant at higher frequency agrees well the reflection loss data. - Highlights: • A series of X-type hexagonal ferrites were prepared by sol–gel method. • The XRD analysis showed that the X-type hexagonal structure. • The c/a ratio of these samples falls in the range of X-type hexagonal ferrites. • FTIR spectra confirms single hexagonal phase. • The magnetic properties vary with the substitution of rare earth elements. • The Gd-doped sample exhibits maximum absorption properties and coercivity.

  1. Large-aperture Tunable Plasma Meta-material to Interact with Electromagnetic Waves

    Science.gov (United States)

    Corke, Thomas; Matlis, Eric

    2016-11-01

    The formation of spatially periodic arrangements of glow discharge plasma resulting from charge instabilities were investigated as a tuneable plasma meta-material. The plasma was formed between two 2-D parallel dielectric covered electrodes: one consisting of an Indium-Tin-Oxide coated glass sheet, and the other consisting of a glass-covered circular electrode. The dielectric covered electrodes were separated by a gap that formed a 2-D channel. The gap spacing was adjustable. The electrodes were powered by a variable amplitude AC generator. The parallel electrode arrangement was placed in a variable pressure vacuum chamber. Various combinations of gap spacing, pressure and voltage resulted in the formation of spatially periodic arrangements (lattice) of glow discharge plasma. The lattice spacing perfectly followed 2-D packing theory, and was fully adjustable through the three governing parameters. Lattice arrangements were designed to interact with electromagnetic (EM) waves in the frequency range between 10GHz-80GHz. Its feasibility was investigate through an EM wave simulation that we adapted to allow for plasma permittivity. The results showed a clear suppression of the EM wave amplitude through the plasma gratings. Supported by AFOSR.

  2. All-optically tunable EIT-like dielectric metasurfaces hybridized with thin phase change material layers

    Science.gov (United States)

    Petronijevic, Emilija; Sibilia, Concita

    2017-05-01

    Electromagnetically induced transparency (EIT), a pump-induced narrow transparency window within the absorption region of a probe, had offered new perspectives in slow-light control in atomic physics. For applications in nanophotonics, the implementation on chip-scaled devices has later been obtained by mimicking this effect by metallic metamaterials. High losses in visible and near infrared range of metal-based metamaterialls have recently opened a new field of all-dielectric metamaterials; a proper configuration of high refractive index dielectric nanoresonators can mimick this effect without losses to get high Q, slow-light response. The next step would be the ability to tune their optical response, and in this work we investigate thin layers of phase change materials (PCM) for all-optical control of EIT-like all-dielectric metamaterials. PCM can be nonvolatively and reversibly switched between two stable phases that differ in optical properties by applying a visible laser pulse. The device is based on Si nanoresonators covered by a thin layer of PCM GeTe; optical and transient thermal simulations have been done to find and optimize the fabrication parameters and switching parameters such as the intensity and duration of the pulse. We have found that the EIT-like response can be switched on and off by applying the 532nm laser pulse to change the phase of the upper GeTe layer. We strongly believe that such approach could open new perspectives in all-optically controlled slow-light metamaterials.

  3. Stimuli-responsive Materials and Structures with Electrically Tunable Mechanical Properties

    Science.gov (United States)

    Auletta, Jeffrey Thomas

    Electricity, a convenient stimulus, was used to manipulate the mechanical properties of two classes of materials, each with a different mechanism. In the first system, macroscale electroplastic elastomer hydrogels (EPEs) were reversibly cycled through soft and hard states by sequential application of oxidative and reductive potentials. Electrochemically reversible crosslinks were switched between strongly binding Fe3+ and weak to non-binding Fe2+, as determined by potentiometric titration.With the incorporation of graphene oxide (GO) into the EPE, a significant enhancement in modulus and toughness was observed, allowing for the preparation of thinner EPE samples, which could be reversibly cycled between soft and hard states over 30 minutes. Further characterization of this EPE by magnetic susceptibility measurements suggested the formation of multinuclear iron clusters within the gel. Copper-derived EPEs which exploited the same redox-controlled mechanism for switching between hard and soft states were also prepared. Here, the density of temporary crosslinks and the mechanical properties were controlled by reversibly switching between the +1 and +2 oxidation states, using a combination of electrochemical/air oxidation and chemical reduction. In addition to undergoing redox-controlled changes in modulus, these EPEs exhibited shape memory. In the second system, electroadhesion between ionomer layers was exploited to create laminate structures whose rigidity depended on the reversible polarization of the dielectric polymers. The role of the counter-ion in determining the intrinsic and electroadhesive properties of poly(ethylene-co-acrylic acid) ionomers in bi- and tri-layered laminate structures was examined. PEAA ionomers were prepared with three tetraalkylammonium cations (NR4 +, R = methyl, TMA+; ethyl, TEA+; and propyl, TPA+). Reflecting the increasing hydrophobicity of the longer alkyl chains, water uptake changed as a function of counterion with TMA+ > TEA

  4. 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.

  5. 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.

  6. MEMS for Tunable Photonic Metamaterial Applications

    Science.gov (United States)

    Stark, Thomas

    Photonic metamaterials are materials whose optical properties are derived from artificially-structured sub-wavelength unit cells, rather than from the bulk properties of the constituent materials. Examples of metamaterials include plasmonic materials, negative index materials, and electromagnetic cloaks. While advances in simulation tools and nanofabrication methods have allowed this field to grow over the past several decades, many challenges still exist. This thesis addresses two of these challenges: fabrication of photonic metamaterials with tunable responses and high-throughput nanofabrication methods for these materials. The design, fabrication, and optical characterization of a microelectromechanical systems (MEMS) tunable plasmonic spectrometer are presented. An array of holes in a gold film, with plasmon resonance in the mid-infrared, is suspended above a gold reflector, forming a Fabry-Perot interferometer of tunable length. The spectra exhibit the convolution of extraordinary optical transmission through the holes and Fabry-Perot resonances. Using MEMS, the interferometer length is modulated from 1.7 mum to 21.67 mum , thereby tuning the free spectral range from about 2900 wavenumbers to 230.7 wavenumbers and shifting the reflection minima and maxima across the infrared. Due to its broad spectral tunability in the fingerprint region of the mid-infrared, this device shows promise as a tunable biological sensing device. To address the issue of high-throughput, high-resolution fabrication of optical metamaterials, atomic calligraphy, a MEMS-based dynamic stencil lithography technique for resist-free fabrication of photonic metamaterials on unconventional substrates, has been developed. The MEMS consists of a moveable stencil, which can be actuated with nanometer precision using electrostatic comb drive actuators. A fabrication method and flip chip method have been developed, enabling evaporation of metals through the device handle for fabrication on an

  7. Tunable radiation emitting semiconductor device

    NARCIS (Netherlands)

    2009-01-01

    A tunable radiation emitting semiconductor device includes at least one elongated structure at least partially fabricated from one or more semiconductor materials exhibiting a bandgap characteristic including one or more energy transitions whose energies correspond to photon energies of light

  8. 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.

  9. 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.

  10. [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.

  11. 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)

  12. 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).

  13. 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.)

  14. 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)

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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%.

  20. 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)

  1. 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.

  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. 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.)

  4. 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.)

  5. Tunable resistance coatings

    Science.gov (United States)

    Elam, Jeffrey W.; Mane, Anil U.

    2015-08-11

    A method and article of manufacture of intermixed tunable resistance composite materials containing at least one of W:Al.sub.2O.sub.3, Mo:Al.sub.2O.sub.3 or M:Al.sub.2O.sub.3 where M is a conducting compound containing either W or Mo. A conducting material and an insulating material are deposited by such methods as ALD or CVD to construct composites with intermixed materials which do not have structure or properties like their bulk counterparts.

  6. 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

  7. 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

  8. 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.

  9. 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)

  10. Tunable laser optics

    CERN Document Server

    Duarte, FJ

    2015-01-01

    This Second Edition of a bestselling book describes the optics and optical principles needed to build lasers. It also highlights the optics instrumentation necessary to characterize laser emissions and focuses on laser-based optical instrumentation. The book emphasizes practical and utilitarian aspects of relevant optics including the essential theory. This revised, expanded, and improved edition contains new material on tunable lasers and discusses relevant topics in quantum optics.

  11. Facile and tunable synthesis of hierarchical mesoporous silica materials ranging from flower structure with wrinkled edges to hollow structure with coarse surface

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Nanjing, E-mail: nanjing.hao@dartmouth.edu [Dartmouth College, Thayer School of Engineering (United States); Li, Laifeng; Tang, Fangqiong, E-mail: tangfq@mail.ipc.ac.cn [Chinese Academy of Sciences, Technical Institute of Physics and Chemistry (China)

    2016-11-15

    Mesoporous silica materials have attracted great attention in many fields. However, facile and tunable synthesis of hierarchical mesoporous silica structures is still a big challenge, and thus the development of them still lags behind. Herein, well-defined mesoporous silica flower structure with wrinkled edges and mesoporous silica hollow structure with coarse surface were synthesized simply by using poly(vinylpyrrolidone) and hexadecylamine as cotemplates in different water/ethanol solvent systems. The shape evolution from flower to hollow can be easily realized by tuning the volume ratio of water to ethanol, and the yields of both materials can reach gram scale. The formation mechanisms of mesoporous silica flower and hollow structures were also experimentally investigated and discussed. These novel hierarchical structures having unique physicochemical properties may bring many interesting insights into scientific research and technological application.

  12. [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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. Three dimensional reduced graphene hydrogels with tunable pore sizes using thiourea dioxide for electrode materials in supercapacitors

    International Nuclear Information System (INIS)

    Xing, Ling-Bao; Zhang, Jing-Li; Zhang, Juan; Hou, Shu-Fen; Zhou, Jin; Si, Weijiang; Cui, Hongyou; Zhuo, Shuping

    2015-01-01

    Graphical abstract: Three-dimensional porous reduced graphene hydrogels with tunable pore size distribution are prepared by using thiourea dioxide in GO suspension with ammonia. - Highlights: • Three-dimensional reduced graphene hydrogels (RGHs) were prepared. • Thiourea dioxide was used as reducing agent with ammonia. • RGHs showed tunable pore size distribution by thiourea dioxide. • RGHs exhibited relatively good electrochemical properties in supercapacitor. - Abstract: In present work, we demonstrate a rapid and easy approach to fabricate three-dimensional (3D) reduced graphene hydrogels (RGHs) by using thiourea dioxide as reducing agents in an aqueous solution of graphene oxide (GO) with ammonia. The transformation of GO suspension to the hydrogels can be confirmed by X-ray powder diffraction, Raman spectroscopy, and Fourier transform infrared spectroscopy. The hierarchical porosity, structure and surface chemical properties can be demonstrated by N 2 sorption experiments, scanning electron microscopy and X-ray photoelectron spectroscopy. With adding different amounts of thiourea dioxide, the obtained RGHs behave different degree of reduction, controlled specific surface area and pore size distribution, and unlike performances in supercapacitors. Benefiting from well-defined and cross-linked 3D porous network architectures, the supercapacitors based on the RGHs in KOH electrolyte exhibited a high specific capacitance of 258.6, 167.3 and 198.3 F g −1 at 0.1 A g −1 for RGHs-1, RGHs-2 and RGHs-5, respectively. Furthermore, this capacitance also showed good electrochemical stability and a high degree of reversibility in the repetitive charge/discharge cycling test

  19. 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.)

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. 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 %.

  5. 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 %

  6. Production of carbonaceous materials with various lengths in small spheroidal fullerenes and long CNTs by tunable multi-walled carbon nanotube cutting

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Hoi; Shin, Ueon Sang [Dankook University, Cheonan (Korea, Republic of)

    2016-10-15

    Tunable cutting of multi-walled carbon nanotubes (CNTs) using high pressure homogenizer and/or HNO{sub 3}/H{sub 2}SO{sub 4} solution was accomplished, resulting in the production of short CNTs with minimum length of 35 nm. Field emission scanning electron microscopy (FE-SEM) and Zeta sizer analysis showed significant reduction of CNT length from this tunable cutting (e.g. from long and entangled pristine CNTs at about 20 μm to ≥1000 nm, ⁓400 nm, ⁓200 nm, and ⁓100 nm via high pressure jet-spraying cutting within 5 h, while chemical cutting process using greatly longer hours (48 h) showed a reduction only to about 1000 nm). When CNT sample of average 1000 nm length previously shortened by HNO{sub 3}/H{sub 2}SO{sub 4} was subjected to the high pressure jet-spraying cutting process, the reduction progressed faster (≤1 h), producing ≥35 nm. Fourier transform infrared spectra and thermogravimetric analysis (TGA) indicated restricted formation of hydrophilic functional groups such as carboxylic group and hydroxyl group in the high pressure jet-spraying cutting, whereas an intensive formation of hydrophilic functional groups on the surface of shortened CNT samples was found after chemical cutting. Such short CNT samples would fulfill the requirements for carbonaceous materials with various lengths in small spheroidal fullerenes and long CNTs. The short CNTs produced are promising for scientific and technological applications in many fields such as electronics, diagnostics, pharmaceuticals, biomedical engineering, and environmental or energy industries.

  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. 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

  9. Polyfunctional inorganic-organic hybrid materials: an unusual kind of NLO active layered mixed metal oxalates with tunable magnetic properties and very large second harmonic generation.

    Science.gov (United States)

    Cariati, Elena; Macchi, Roberto; Roberto, Dominique; Ugo, Renato; Galli, Simona; Casati, Nicola; Macchi, Piero; Sironi, Angelo; Bogani, Lapo; Caneschi, Andrea; Gatteschi, Dante

    2007-08-01

    Mixed M(II)/M(III) metal oxalates, as "stripes" connected through strong hydrogen bonding by para-dimethylaminobenzaldeide (DAMBA) and water, form an organic-inorganic 2D network that enables segregation in layers of the cationic organic NLO-phore trans-4-(4-dimethylaminostyryl)-1-methylpyridinium, [DAMS+]. The crystalline hybrid materials obtained have the general formula [DAMS]4[M2M'(C2O4)6].2DAMBA.2H2O (M = Rh, Fe, Cr; M' = Mn, Zn), and their overall three-dimensional packing is non-centrosymmetric and polar, therefore suitable for second harmonic generation (SHG). All the compounds investigated are characterized by an exceptional SHG activity, due both to the large molecular quadratic hyperpolarizability of [DAMS+] and to the efficiency of the crystalline network which organizes [DAMS+] into head-to-tail arranged J-type aggregates. The tunability of the pairs of metal ions allows exploiting also the magnetic functionality of the materials. Examples containing antiferro-, ferro-, and ferri-magnetic interactions (mediated by oxalato bridges) are obtained by coupling proper M(III) ions (Fe, Cr, Rh) with M(II) (Mn, Zn). This shed light on the role of weak next-nearest-neighbor interactions and main nearest-neighbor couplings along "stripes" of mixed M(II)/M(III) metal oxalates of the organic-inorganic 2D network, thus suggesting that these hybrid materials may display isotropic 1D magnetic properties along the mixed M(II)/M(III) metal oxalates "stripes".

  10. 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

  11. 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.

  12. Molecular beam epitaxy growth of [CrGe/MnGe/FeGe] superlattices: Toward artificial B20 skyrmion materials with tunable interactions

    Science.gov (United States)

    Ahmed, Adam S.; Esser, Bryan D.; Rowland, James; McComb, David W.; Kawakami, Roland K.

    2017-06-01

    Skyrmions are localized magnetic spin textures whose stability has been shown theoretically to depend on material parameters including bulk Dresselhaus spin orbit coupling (SOC), interfacial Rashba SOC, and magnetic anisotropy. Here, we establish the growth of a new class of artificial skyrmion materials, namely B20 superlattices, where these parameters could be systematically tuned. Specifically, we report the successful growth of B20 superlattices comprised of single crystal thin films of FeGe, MnGe, and CrGe on Si(1 1 1) substrates. Thin films and superlattices are grown by molecular beam epitaxy and are characterized through a combination of reflection high energy electron diffraction, X-ray diffraction, and cross-sectional scanning transmission electron microscopy (STEM). X-ray energy dispersive spectroscopy (XEDS) distinguishes layers by elemental mapping and indicates good interface quality with relatively low levels of intermixing in the [CrGe/MnGe/FeGe] superlattice. This demonstration of epitaxial, single-crystalline B20 superlattices is a significant advance toward tunable skyrmion systems for fundamental scientific studies and applications in magnetic storage and logic.

  13. Signal sensitivity of alternating current potential drop measurement for crack detection of conductive substrate with tunable coating materials through finite element modeling

    International Nuclear Information System (INIS)

    Rao, Simha Sandeep; Zhao, Huijuan; Liu, Ming; Peng, Fei; Zhang, Bo

    2016-01-01

    We adopt a finite element numerical modeling approach to investigate the electromagnetic coupling effect of two parallel electric conductors with tunable electric conductivity σ and magnetic permeability μ . For two parallel conductors C and S ( μ C   ⋅  σ C   ≤  μ S   ⋅  σ S ), we find that the shape of current density profile of conductor S is dependent on the product of μ C   ⋅  σ C , while the magnitude is determined by the AC current frequency f . On the other hand, the frequency f affects not only the shape but also the magnitude of the current density profile of conductor C. We further adopt a coplanar model to investigate the signal sensitivity of alternating current potential drop (ACPD) measurement for both surface crack and inner crack detection. We find that with modified coating materials (lower electric conductivity and higher magnetic permeability, compared with the substrate material properties), the crack detection signal sensitivity can be greatly enhanced for both the cracks within the coating and at the coating/substrate interface, where cracks are most commonly encountered in real situations. (paper)

  14. Scalable Solution Processing of Pristine Carbon Nanotubes for Self-Assembled, Tunable Materials with Direct Application to Space Technologies

    Data.gov (United States)

    National Aeronautics and Space Administration — Current material technologies limit space exploration and vehicle performance due to often unnecessary mass increase from copper wiring or heavy structural...

  15. Landau-Devonshire Parameters for the Tunable Paraelectric Material BaTi.9(Sc,Ta).05O3

    National Research Council Canada - National Science Library

    Miller, Virginia; Crowne, Frank

    2008-01-01

    ...).05O3 are used to deduce the thermodynamic Landau-Devonshire parameters of the material, which are found to differ strongly from those of the parent material BaTiO3, despite the small amount of added Sc and Ta...

  16. 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."

  17. 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...

  18. 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.

  19. Tunable resistive pulse sensing: potential applications in nanomedicine.

    Science.gov (United States)

    Sivakumaran, Muttuswamy; Platt, Mark

    2016-08-01

    An accurate characterization of nanomaterials used in clinical diagnosis and therapeutics is of paramount importance to realize the full potential of nanotechnology in medicine and to avoid unexpected and potentially harmful toxic effects due to these materials. A number of technical modalities are currently in use to study the physical, chemical and biological properties of nanomaterials but they all have advantages and disadvantages. In this review, we discuss the potential of a relative newcomer, tunable resistive pulse sensing, for the characterization of nanomaterials and its applications in nanodiagnostics.

  20. 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.

  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. Gallium containing composites as a tunable material to understand neuronal behavior under variable stiffness and radiation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Berg, Nora G.; Pearce, Brady L.; Rohrbaugh, Nathaniel [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Jiang, Lin [Materials Science and Engineering, University of New South Wales, Sydney (Australia); Nolan, Michael W. [Department of Clinical Sciences (College of Veterinary Medicine), Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27606 (United States); Ivanisevic, Albena, E-mail: ivanisevic@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States)

    2017-02-01

    We report a composite biomaterial containing nanostructured GaOOH and Matrigel™ that can be modulated with respect to its stiffness and radiosensitization properties. A variety of concentrations of GaOOH were added to the composite to alter the mechanical properties of the material as well as to tune the radiosensitizing properties to the composite. PC-12 cells were used to study the combined effects of different stimuli on cell behavior. NGF was given to the cells to record their morphology as well as viability. An increase in the substrate stiffness caused an increase in neurite outgrowth but a decrease in cell viability. In addition, increasing the radiation dose decreased neurite outgrowth but increased cell viability when radiosensitizing particles were present. A subtractive effect between radiosensitizing and mechanical stimuli was observed when PC-12 cells were grown on the GaOOH containing composite. - Highlights: • A composite containing GaOOH and Matrigel can be used to study neurotypic cell behavior. • The composite material can be used to modulate multiple stimuli. • The neurotypic cell behavior can be altered during radiation based on the amount of GaOOH present.

  3. 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...

  4. 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

  5. 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.)

  6. 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,

  7. A facile synthesis of C{sub 60}-organosilicon hybrid polymers: Considering their tunable optical properties for spin-on-silicon hardmask materials

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jin-Kyu; Dao, Tung Duy; Kim, Ye-Seul; Jeong, Hyun-Dam, E-mail: hdjeong@chonnam.ac.kr

    2016-09-15

    Organic-inorganic hybrid materials with high refractive index have attracted considerable attention for many optoelectronic applications, including spin-on-type hardmask for ArF lithography (193 nm). In this study, we demonstrate the synthesis of a C{sub 60}-embedded organosilicon hybrid polymer, C{sub 60}-embedded poly-xylene-hexamethyltrisiloxane hybrid (C{sub 60}-PXS), of tunable optical properties. C{sub 60} was covalently bonded to the PXS backbone through Pt-catalyzed hydrosilylation, in which the PXS was formed possibly by unexpected transition metal-catalyzed benzylic C−H silylation and oxygenation of the o-xylene. The C{sub 60}-PXS thin films fabricated using a spin-coating method showed much higher refractive index by 5–22% according to the curing temperatures, than the PXS thin films containing no C{sub 60}. In particular, the C{sub 60}-PXS thin film cured at 350 °C showed the refractive index (n) and extinction coefficient (k) at 193 nm to be 1.61 and 0.29 that are very close to the optimum values for the Si-hardmask. This implies the high applicability of the C{sub 60}-embedded organosilicon hybrid polymer, C{sub 60}-PXS, for the spin-on Si-hardmask in ArF lithography. - Highlights: • A facile synthetic route for C{sub 60}-embedded organosilicon hybrid polymer was presented. • The hybrid polymer showed much higher refractive index than the polymer without C{sub 60}. • The hybrid polymer is highly applicable for Si-hardmask in terms of optical properties. • It is believed that the properties of the hybrid polymer can be further optimized.

  8. 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)

  9. Tunable optical switching in the near-infrared spectral regime by employing plasmonic nanoantennas containing phase change materials.

    Science.gov (United States)

    Savaliya, Priten B; Thomas, Arun; Dua, Rishi; Dhawan, Anuj

    2017-10-02

    We propose the design of switchable plasmonic nanoantennas (SPNs) that can be employed for optical switching in the near-infrared regime. The proposed SPNs consist of nanoantenna structures made up of a plasmonic metal (gold) such that these nanoantennas are filled with a switchable material (vanadium dioxide). We compare the results of these SPNs with inverted SPN structures that consist of gold nanoantenna structures surrounded by a layer of vanadium dioxide (VO 2 ) on their outer surface. These nanoantennas demonstrate switching of electric-field intensity enhancement (EFIE) between two states (On and Off states), which can be induced thermally, optically or electrically. The On and Off states of the nanoantennas correspond to the metallic and semiconductor states, respectively of the VO 2 film inside or around the nanoantennas, as the VO 2 film exhibits phase transition from its semiconductor state to the metallic state upon application of thermal, optical, or electrical energy. We employ finite-difference time-domain (FDTD) simulations to demonstrate switching in the EFIE for four different SPN geometries - nanorod-dipole, bowtie, planar trapezoidal toothed log-periodic, and rod-disk - and compare their near-field distributions for the On and Off states of the SPNs. We also demonstrate that the resonance wavelength of the EFIE spectra gets substantially modified when these SPNs switch between the two states.

  10. 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.

  11. 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.

  12. 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.

  13. 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…

  14. 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.

  15. 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.

  16. Tunable laser applications

    CERN Document Server

    Duarte, FJ

    2008-01-01

    Introduction F. J. Duarte Spectroscopic Applications of Tunable Optical Parametric Oscillators B. J. Orr, R. T. White, and Y. He Solid-State Dye Lasers Costela, I. García-Moreno, and R. Sastre Tunable Lasers Based on Dye-Doped Polymer Gain Media Incorporating Homogeneous Distributions of Functional Nanoparticles F. J. Duarte and R. O. James Broadly Tunable External-Cavity Semiconductor Lasers F. J. Duarte Tunable Fiber Lasers T. M. Shay and F. J. Duarte Fiber Laser Overview and Medical Applications

  17. Tunable Microwave Filter Design Using Thin-Film Ferroelectric Varactors

    Science.gov (United States)

    Haridasan, Vrinda

    Military, space, and consumer-based communication markets alike are moving towards multi-functional, multi-mode, and portable transceiver units. Ferroelectric-based tunable filter designs in RF front-ends are a relatively new area of research that provides a potential solution to support wideband and compact transceiver units. This work presents design methodologies developed to optimize a tunable filter design for system-level integration, and to improve the performance of a ferroelectric-based tunable bandpass filter. An investigative approach to find the origins of high insertion loss exhibited by these filters is also undertaken. A system-aware design guideline and figure of merit for ferroelectric-based tunable band- pass filters is developed. The guideline does not constrain the filter bandwidth as long as it falls within the range of the analog bandwidth of a system's analog to digital converter. A figure of merit (FOM) that optimizes filter design for a specific application is presented. It considers the worst-case filter performance parameters and a tuning sensitivity term that captures the relation between frequency tunability and the underlying material tunability. A non-tunable parasitic fringe capacitance associated with ferroelectric-based planar capacitors is confirmed by simulated and measured results. The fringe capacitance is an appreciable proportion of the tunable capacitance at frequencies of X-band and higher. As ferroelectric-based tunable capac- itors form tunable resonators in the filter design, a proportionally higher fringe capacitance reduces the capacitance tunability which in turn reduces the frequency tunability of the filter. Methods to reduce the fringe capacitance can thus increase frequency tunability or indirectly reduce the filter insertion-loss by trading off the increased tunability achieved to lower loss. A new two-pole tunable filter topology with high frequency tunability (> 30%), steep filter skirts, wide stopband

  18. 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.)

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  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. Micromachined tunable metamaterials: a review

    International Nuclear Information System (INIS)

    Liu, A Q; Zhu, W M; Tsai, D P; Zheludev, N I

    2012-01-01

    This paper reviews micromachined tunable metamaterials, whereby the tuning capabilities are based on the mechanical reconfiguration of the lattice and/or the metamaterial element geometry. The primary focus of this review is the feasibility of the realization of micromachined tunable metamaterials via structure reconfiguration and the current state of the art in the fabrication technologies of structurally reconfigurable metamaterial elements. The micromachined reconfigurable microstructures not only offer a new tuning method for metamaterials without being limited by the nonlinearity of constituent materials, but also enable a new paradigm of reconfigurable metamaterial-based devices with mechanical actuations. With recent development in nanomachining technology, it is possible to develop structurally reconfigurable metamaterials with faster tuning speed, higher density of integration and more flexible choice of the working frequencies. (review article)

  8. 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.

  9. Graphene and graphene-like two-denominational materials based fluorescence resonance energy transfer (FRET) assays for biological applications.

    Science.gov (United States)

    Tian, Feng; Lyu, Jing; Shi, Jingyu; Yang, Mo

    2017-03-15

    In the past decades, Förster resonance energy transfer (FRET) has been applied in many biological applications to reveal the biological information at the nanoscale. Recently, graphene and graphene-like two-dimensional (2D) nanomaterials started to be used in FRET assays as donors or acceptors including graphene oxide (GO), graphene quantum dot (GQD), graphitic-carbon nitride nanosheets (g-C 3 N 4 ) and transition metal dichalcogenides (e.g. MoS 2 , MnO 2, and WS 2 ). Due to the remarkable properties such as large surface to volume ratio, tunable energy band, photoluminescence and excellent biocompatibility, these 2D nanomaterials based FRET assays have shown great potential in various biological applications. This review summarizes the recent development of graphene and graphene-like 2D nanomaterials based FRET assays in applications of biosensing, bioimaging, and drug delivery monitoring. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. 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

  11. Water: Promising Opportunities For Tunable All-dielectric Electromagnetic Metamaterials

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Kuznetsova, Svetlana M.; Zhukovsky, Sergei

    2015-01-01

    We reveal an outstanding potential of water as an inexpensive, abundant and bio-friendly high-refractive-index material for creating tunable all-dielectric photonic structures and metamaterials. Specifically, we demonstrate thermal, mechanical and gravitational tunability of magnetic and electric...

  12. [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.

  13. 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

  14. 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.

  15. 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...

  16. 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)

  17. 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

  18. 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)

  19. 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....

  20. 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

  1. 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.

  2. 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)

  3. 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)

  4. 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

  5. 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.

  6. Magnetostatic wave tunable resonators

    Science.gov (United States)

    Castera, J.-P.; Hartemann, P.

    1983-06-01

    Theoretical principles and techniques for the implementation of magnetostatic surface wave and volume wave resonators in high frequency oscillators are discussed. Magnetostatic waves are magnetic waves that propagate in materials exposed to a polarized magnetic field. The propagation speed ranges from 3-300 km/sec for wavelengths between 1 micron and 10 mm, in the presence of lags from 10-1000 nsec/ cm. Tunable resonators in the 1-20 GHz frequency range have been manufactured with YIG using liquid phase epitaxy for deposition on gadolinium and gallium substrates. Distributed-mirror Fabry-Perot cavity resonators are described and performance tests results are reported, including losses of 8 dB, a quality coefficient under voltage of 450, and frequency rejection outside of resonance better than 10 dB. However, saturation occurs at low power levels at frequencies lower than 4.2 GHz, a feature overcome with forward volume magnetostatic wave generators, which have a quality factor of 500, an insertion loss of 22 dB, and rejection around 15 dB.

  7. 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.

  8. 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.

  9. 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....

  10. 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...

  11. 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...

  12. 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)

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 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…

  18. 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)

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.))

  6. Perovskite Superlattices as Tunable Microwave Devices

    Science.gov (United States)

    Christen, H. M.; Harshavardhan, K. S.

    2003-01-01

    Experiments have shown that superlattices that comprise alternating epitaxial layers of dissimilar paraelectric perovskites can exhibit large changes in permittivity with the application of electric fields. The superlattices are potentially useful as electrically tunable dielectric components of such microwave devices as filters and phase shifters. The present superlattice approach differs fundamentally from the prior use of homogeneous, isotropic mixtures of base materials and dopants. A superlattice can comprise layers of two or more perovskites in any suitable sequence (e.g., ABAB..., ABCDABCD..., ABACABACA...). Even though a single layer of one of the perovskites by itself is not tunable, the compositions and sequence of the layers can be chosen so that (1) the superlattice exhibits low microwave loss and (2) the interfacial interaction between at least two of the perovskites in the superlattice renders either the entire superlattice or else at least one of the perovskites tunable.

  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. Designed synthesis of tunable amorphous carbon nanotubes (a ...

    Indian Academy of Sciences (India)

    Administrator

    Page 1. Electronic Supplementary Material. Graphical abstract. Designed synthesis of tunable amorphous carbon nanotubes (a-CNTs) by a novel route and their oxidation resistance properties by Longlong. Xu et al (pp 1397–1402).

  9. A bio-inspired approach for in situ synthesis of tunable adhesive

    International Nuclear Information System (INIS)

    Sun, Leming; Yi, Sijia; Wang, Yongzhong; Pan, Kang; Zhong, Qixin; Zhang, Mingjun

    2014-01-01

    Inspired by the strong adhesive produced by English ivy, this paper proposes an in situ synthesis approach for fabricating tunable nanoparticle enhanced adhesives. Special attention was given to tunable features of the adhesive produced by the biological process. Parameters that may be used to tune properties of the adhesive will be proposed. To illustrate and validate the proposed approach, an experimental platform was presented for fabricating tunable chitosan adhesive enhanced by Au nanoparticles synthesized in situ. This study contributes to a bio-inspired approach for in situ synthesis of tunable nanocomposite adhesives by mimicking the natural biological processes of ivy adhesive synthesis. (paper)

  10. 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.)

  11. 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)

  12. 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.

  13. 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.

  14. 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. 

  15. 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...

  16. 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.)

  17. 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

  18. 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)

  19. 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.

  20. 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.

  1. 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.

  2. 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)

  3. Mechanical, Biological and Electrochemical Investigations of Advanced Micro/Nano Materials for Tissue Engineering and Energy Storage

    Science.gov (United States)

    Pu, Juan

    Various micro/nano materials have been extensively studied for applications in tissue engineering and energy storage. Tissue engineering seeks to repair or replace damaged tissue by integrating approaches from cellular/molecular biology and material chemistry/engineering. A major challenge is the consistent design of three-dimensional (3D) scaffolds that mimic the structure and biological functions of extracellular matrix (ECM), guide cell migration, provide mechanical support, and regulate cell activity. Electrospun micro/nanofibers have been investigated as promising tissue engineering scaffolds because they resemble native ECM and possess tunable surface morphologies. Supercapacitors, one of the energy storage devices, bridge the performance gap between rechargeable batteries and conventional capacitors. Active electrode materials of supercapacitors must possess high specific surface area, high conductivity, and good electrochemical properties. Carbon-based micro/nano-particles, such as graphene, activated carbon (AC), and carbon nanotubes, are commonly used as active electrode materials for storing charge in supercapacitors by the electrical double layer mechanism due to their high specific surface area and excellent conductivity. In this thesis, the mechanical properties of electrospun bilayer microfibrous membranes were investigated for potential applications in tissue engineering. Bilayer microfibrous membranes of poly(l-lactic acid) (PLLA) were fabricated by electrospinning using a parallel-disk mandrel configuration, which resulted in the sequential deposition of a layer with aligned fibers (AFL) across the two parallel disks and a layer with random fibers (RFL), both deposited by a single process step. The membrane structure and fiber alignment were characterized by scanning electron microscopy and two-dimensional fast Fourier transform. Because of the intricacies of the generated electric field, the bilayer membranes exhibited higher porosity than the

  4. Tunable Microfluidic Dye Laser

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Helbo, Bjarne; Kutter, Jörg Peter

    2003-01-01

    We present a tunable microfluidic dye laser fabricated in SU-8. The tunability is enabled by integrating a microfluidic diffusion mixer with an existing microfluidic dye laser design by Helbo et al. By controlling the relative flows in the mixer between a dye solution and a solvent......, the concentration of dye in the laser cavity can be adjusted, allowing the wavelength to be tuned. Wavelength tuning controlled by the dye concentration was demonstrated with macroscopic dye lasers already in 1971, but this principle only becomes practically applicable by the use of microfluidic mixing...

  5. 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

  6. 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)

  7. 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.

  8. A Microwave Tunable Bandpass Filter for Liquid Crystal Applications

    Science.gov (United States)

    Cao, Weiping; Jiang, Di; Liu, Yupeng; Yang, Yuanwang; Gan, Baichuan

    2017-07-01

    In this paper, a novel microwave continuously tunable band-pass filter, based on nematic liquid crystals (LCs), is proposed. It uses liquid crystal (LC) as the electro-optic material to mainly realize frequency shift at microwave band by changing the dielectric anisotropy, when applying the bias voltage. According to simulation results, it achieves 840 MHz offset. Comparing to the existing tunable filter, it has many advantages, such as continuously tunable, miniaturization, low processing costs, low tuning voltage, etc. Thus, it has shown great potentials in frequency domain and practical applications in modern communication.

  9. Tunable Microwave Component Technologies for SatCom-Platforms

    Science.gov (United States)

    Maune, Holger; Jost, Matthias; Wiens, Alex; Weickhmann, Christian; Reese, Roland; Nikfalazar, Mohammad; Schuster, Christian; Franke, Tobias; Hu, Wenjuan; Nickel, Matthias; Kienemund, Daniel; Prasetiadi, Ananto Eka; Jakoby, Rolf

    2017-03-01

    Modern communication platforms require a huge amount of switched RF component banks especially made of different filters and antennas to cover all operating frequencies and bandwidth for the targeted services and application scenarios. In contrast, reconfigurable devices made of tunable components lead to a considerable reduction in complexity, size, weight, power consumption, and cost. This paper gives an overview of suitable technologies for tunable microwave components especially for SatCom applications. Special attention is given to tunable components based on functional materials such as barium strontium titanate (BST) and liquid crystal (LC).

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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

  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. "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.

  19. 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.

  20. [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.

  1. Synthesis and Characterization of Rhodamine B-ethylenediamine-hyaluronan Acid as Potential Biological Functional Materials

    Science.gov (United States)

    Li, Y. L.; Wang, W. X.; Wang, Y.; Zhang, W. B.; Gong, H. M.; Liu, M. X.

    2018-05-01

    The purpose of this study is to synthesize and characterize fluorescent polymers, rhodamine B-ethylenediamine-hyaluronan acid (RhB-EA-HA). RhB-EA-HA was successfully synthesized by ester ammonolysis reaction and amidation reaction. Moreover, the structural properties of RhB-EA-HA were characterized by 1H-NMR spectra, UV-vis spectrometry and Fourier transform infrared spectroscopy (FT-IR). RhB-EA-HA can be grafted on the surface of silica nanomaterials, which may be potential biological functional materials for drug delivery system.

  2. Utilisation of biological and secondary raw materials IX. Recycling - conversion to energy

    International Nuclear Information System (INIS)

    Wiemer, Klaus; Kern, Michael; Raussen, Thomas

    2014-01-01

    The book on the utilization of biological and secondary raw materials covers the following issues: Perspectives of the circular flow and resource economy, waste avoidance, closed substance cycle waste management law and biowaste assessment, economic evaluation and usage alternatives for biogas, consequences of the 4th BlmschV, the BioAbfV and the DueV for the biowaste treatment, alternative techniques of the Biowaste collection, alternative models of the recyclable substance assessment, future of the packaging and recyclable substance utilization, ElectroG and E-scrape recycling, innovative concepts for the municipal waste management, future of the MBA, MVA and EBS management.

  3. A complex neutron activation method for the analysis of biological materials

    International Nuclear Information System (INIS)

    Ordogh, M.

    1978-01-01

    The aim of the present work was to deal primarily with a few essential trace elements and to obtain reliable results of adequate accuracy and precision for the analysis of biological samples. A few other than trace elements were determined by the nondestructive technique as they can be well evaluated from the gamma-spectra. In the development of the method BOWEN's kale was chosen as model material. To confirm the reliability of the method two samples were analysed proposed by the IAEA in the frame of an international comparative analysis series. The comparative analysis shows the present method to be reliable, the precision and accuracy are good. (author)

  4. Non-proliferation issues in the field of biological technologies and dual-use materials

    International Nuclear Information System (INIS)

    Mamadaliev, S.M.; Troitskij, E.N.; Ibraev, R.

    2001-01-01

    In the paper the results of the DTRA 01-00-C-0030 'Strengthening of physical and biological protection' project at the Research Agricultural Institute (Kazakhstan) are discussed. The project was directed on the organization of a reliable physical integrity of dangerous pathogens, on the provision reliable protection around the periphery and outside security of the whole object as well as on the exclusion of possibility of pathogens expansion of dangerous infection material out the controlled working conditions. The central section of the protection is storehouse of microorganism culture

  5. Analytical methods for determination of terbinafine hydrochloride in pharmaceuticals and biological materials

    Directory of Open Access Journals (Sweden)

    Basavaiah Kanakapura

    2016-06-01

    Full Text Available Terbinafine is a new powerful antifungal agent indicated for both oral and topical treatment of mycosessince. It is highly effective in the treatment of determatomycoses. The chemical and pharmaceutical analysis of the drug requires effective analytical methods for quality control and pharmacodynamic and pharmacokinetic studies. Ever since it was introduced as an effective antifungal agent, many methods have been developed and validated for its assay in pharmaceuticals and biological materials. This article reviews the various methods reported during the last 25 years.

  6. Ionometric determination of boron in natural, waste waters and biological materials

    International Nuclear Information System (INIS)

    Yakimov, V.P.; Markova, O.L.

    1992-01-01

    Method have been developed for the determination of boron in natural, waste waters and biological materials using direct potentiometry with a BF 4 - selective electrode. In order to estimate the matrix effects in plotting the calibration graphs, it is recommended to and the test water or solution of biomaterial mineralizates, containing boron in electrode-inactive form, to the calibration solutions before e.m.f. measurements version of boron into tetrafluoroborate in solid phase on heating the mineralized samples with ammonium bifluoride at 150-180 deg C

  7. A complex method for the neutron activation analysis of biological materials

    International Nuclear Information System (INIS)

    Ordogh, M.

    1978-05-01

    The destructive and nondestructive approach of neutron activation analysis used by the author is reviewed to determine some trace elements in biological materials: Ca, Cl, Co, Cu, Fe, K, Mg, Mn, Na, Rb, Sb, Sc, V and Zn. Bowen's kale was used to determine the accuracy and reliability. The parameters obtained were confirmed by participating in round robins organized by the IAEA: in which potato powder and animal bone have been analyzed for Zn, Co, Fe, Cr, Mn, Rb, Na, K and Cu. Tabulated results are given and compared with recommended values and literature data. Gamma spectra are shown. (T.G.)

  8. Freely tunable broadband polarization rotator for terahertz waves.

    Science.gov (United States)

    Fan, Ren-Hao; Zhou, Yu; Ren, Xiao-Ping; Peng, Ru-Wen; Jiang, Shang-Chi; Xu, Di-Hu; Xiong, Xiang; Huang, Xian-Rong; Wang, Mu

    2015-02-18

    A freely tunable polarization rotator for broadband terahertz waves is demonstrated using a three-rotating-layer metallic grating structure, which can conveniently rotate the polarization of a linearly polarized terahertz wave to any desired direction with nearly perfect conversion efficiency. This low-cost, high-efficiency, and freely tunable device has potential applications as material analysis, wireless communication, and THz imaging. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. MAK and BAT values list 2014. Maximum permissible concentrations at the place of work and biological tolerance values for working materials

    International Nuclear Information System (INIS)

    2014-01-01

    The book on the MAK (maximum permissible concentrations at the place of work) and BAT (biological tolerance values for working materials) value list 2014 includes the following chapters: (a) Maximum permissible concentrations at the place of work: definition, application and determination of MAT values, list of materials; carcinogenic working materials, sensibilizing working materials, aerosols, limiting the exposition peaks, skin resorption, MAK values during pregnancy, germ cell mutagens, specific working materials; (b) Biological tolerance values for working materials: definition and application of BAT values, list of materials, carcinogenic working materials, biological guide values, biological working material reference values.

  10. MAK and BAT values list 2015. Maximum permissible concentrations at the place of work and biological tolerance values for working materials

    International Nuclear Information System (INIS)

    2015-01-01

    The book on the MAK (maximum permissible concentrations at the place of work) and BAT (biological tolerance values for working materials) value list 2015 includes the following chapters: (a) Maximum permissible concentrations at the place of work: definition, application and determination of MAT values, list of materials; carcinogenic working materials, sensibilizing working materials, aerosols, limiting the exposition peaks, skin resorption, MAK values during pregnancy, germ cell mutagens, specific working materials; (b) Biological tolerance values for working materials: definition and application of BAT values, list of materials, carcinogenic working materials, biological guide values, biological working material reference values.

  11. The monostandard method in thermal neutron activation analysis of geological, biological and environmental materials

    International Nuclear Information System (INIS)

    Alian, A.; Djingova, R.G.; Kroener, B.; Sansoni, B.

    1984-01-01

    A simple method is described for instrumental multielement thermal neutron activation analysis using a monostandard. For geological and air dust samples, iron is used as a comparator, while sodium has advantages for biological materials. To test the capabilities of this method, the values of the effective cross sections of the 23 elements determined were evaluated in a reactor site with an almost pure thermal neutron flux of about 9x10 12 nxcm -2 xs -1 and an epithermal neutron contribution of less than 0.03%. The values obtained were found to agree mostly well with the best literature values of thermal neutron cross sections. The results of an analysis by activation in the same site agree well with the relative method using multielement standards and for several standard reference materials with certified element contents. A comparison of the element contents obtained by the monostandard and relative methods together with corresponding precisions and accuracies is given. (orig.) [de

  12. Stopping powers for protons in materials of interest in dosimetry and in medical and biological applications

    International Nuclear Information System (INIS)

    Thwaites, D.I.

    1985-01-01

    Stopping powers are required for many radiation applications in medicine and biology. Their accuracy can be critical. Some published calculations for these situations have not included recent developments in stopping power theory or the body of work on deviations from additivity due to phase of chemical binding effects. These areas have recently been reviewed and mean excitation energies recommended for a range of materials of interest. Calculated stopping powers are presented for protons of 0.4 to 200 MeV taking the available information into account. The materials considered are Lucite, ICRU composition muscle and bone, A-150 plastic, a TE gas, acetylene and polystyrene and water and water vapour. With suitable corrections and suitable I values in the Bethe stopping power expression, accuracies of <2% can be achieved. (author)

  13. Biological availability of energy related effluent material in the coastal ecosystem

    International Nuclear Information System (INIS)

    Gibson, C.I.; Abel, K.H.; Ahlstrom, S.W.; Crecelius, E.A.; Schmidt, R.L.; Thatcher, T.O.; Wildung, R.E.

    1977-01-01

    In order to make the predictions necessary to forecast the ecological consequences of an energy-related technology, there must be an understanding of: the biogeochemical processes involved in the natural system; the manner in which an energy technology affects these processes and how, in turn, this affects the ecosystem as a whole. Direct biological effects such as lethality, behavioral changes, and physiological changes, are being studied under the program previously discussed. The biological availability and impact studies are investigating: the chemical, physical, and biological processes that occur in the natural marine ecosystem; how energy effluents affect these processes; and the factors involved in regulating the bioavailability of effluent material. This past year's effort has centered on defining the quantities and forms of metals and radioisotopes in nuclear power plant effluent streams, the chemical forms present in bioassay systems, the chemical and microbial processes controlling the forms of metals available from the sediments, and the uptake and control of copper in shrimp. In addition, several sites in Sequim Bay have been monitored for potential use in field verification studies

  14. Human biological monitoring for exposure assessment in response to an incident involving hazardous materials.

    Science.gov (United States)

    Scheepers, Paul T J; van Brederode, Nelly E; Bos, Peter M J; Nijhuis, Nicole J; van de Weerdt, Rik H J; van der Woude, Irene; Eggens, Martin L

    2014-12-15

    Biological monitoring in humans (HBM) is widely used in the field of occupational and environmental health. In the situation of an unexpected release of hazardous materials HBM may contribute to the medical support and treatment of exposed individuals from the general population or of emergency responders. Such exposure information may also be used to respond to individual concerns such as questions about a possible relationship between the chemicals released during the incident and health effects. In The Netherlands a guideline was prepared to support early decision-making about the possible use of HBM for exposure assessment during or as soon as possible following a chemical incident. The application of HBM in such an emergency setting is not much different from situations where HBM is normally used but there are some issues that need extra attention such as the choice of the biomarker, the biological media to be sampled, the time point at which biological samples should be collected, the ethics approval and technical implementation of the study protocol and the interpretation and communication of the study results. These issues addressed in the new guideline will support the use of HBM in the management of chemical disasters. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  15. Occupational exposure to potentially infectious biological material in a dental teaching environment.

    Science.gov (United States)

    Machado-Carvalhais, Helenaura P; Ramos-Jorge, Maria L; Auad, Sheyla M; Martins, Laura H P M; Paiva, Saul M; Pordeus, Isabela A

    2008-10-01

    The aims of this cross-sectional study were to determine the prevalence of occupational accidents with exposure to biological material among undergraduate students of dentistry and to estimate potential risk factors associated with exposure to blood. Data were collected through a self-administered questionnaire (86.4 percent return rate), which was completed by a sample of 286 undergraduate dental students (mean age 22.4 +/-2.4 years). The students were enrolled in the clinical component of the curriculum, which corresponds to the final six semesters of study. Descriptive, bivariate, simple logistic regression and multiple logistic regression (Forward Stepwise Procedure) analyses were performed. The level of statistical significance was set at 5 percent. Percutaneous and mucous exposures to potentially infectious biological material were reported by 102 individuals (35.6 percent); 26.8 percent reported the occurrence of multiple episodes of exposure. The logistic regression analyses revealed that the incomplete use of individual protection equipment (OR=3.7; 95 percent CI 1.5-9.3), disciplines where surgical procedures are carried out (OR=16.3; 95 percent CI 7.1-37.2), and handling sharp instruments (OR=4.4; 95 percent CI 2.1-9.1), more specifically, hollow-bore needles (OR=6.8; 95 percent CI 2.1-19.0), were independently associated with exposure to blood. Policies of reviewing the procedures during clinical practice are recommended in order to reduce occupational exposure.

  16. Accidents with biological material among undergraduate nursing students in a public Brazilian university.

    Science.gov (United States)

    Reis, Renata Karina; Gir, Elucir; Canini, Silvia Rita M S

    2004-02-01

    During their academic activities, undergraduate nursing students are exposed to contamination by bloodborne pathogens, as well as by others found in body fluids, among which are the Human Immunodeficiency (HIV), Hepatitis B and C viruses. We developed a profile of victimized students, characterizing accidents with biological material occurring among undergraduate nursing students at a public university in São Paulo State, Brazil. We identified the main causes and evaluated the conduct adopted by students and their reactions and thoughts concerning the accidents. Seventy-two accidents were identified, of which 17% involved potentially contaminated biological material. Needles were the predominant cause of accidents. The most frequently involved topographic areas were the fingers. Only five students reported the accidents and sought medical care. Among these, two students were advised to begin prophylactic treatment against HIV infection by means of antiretroviral drugs. It was found that the risk of accidents is underestimated and that strategies such as formal teaching and continual training are necessary in order to make students aware of biosafety measures.

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

    Directory of Open Access Journals (Sweden)

    Lillian Kelly de Oliveira Lopes

    2006-12-01

    Full Text Available 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. Among these, 621 (10,76% were about professional accident, 25 (4,03% of this amount came from the own hospital and 596 (95,97% from other services. The article verified that workers proceeding from big services are leaded to the hospital evaluated. It´s important to structure health´s services to optimize the worker´s attending in the original´s unit. KEYWORDS: Occupational accidents; Occupational risk; Occupational Accidents registry.

  18. Accidents with biological material among undergraduate nursing students in a public Brazilian university

    Directory of Open Access Journals (Sweden)

    Renata Karina Reis

    Full Text Available During their academic activities, undergraduate nursing students are exposed to contamination by bloodborne pathogens, as well as by others found in body fluids, among which are the Human Immunodeficiency (HIV, Hepatitis B and C viruses. We developed a profile of victimized students, characterizing accidents with biological material occurring among undergraduate nursing students at a public university in São Paulo State, Brazil. We identified the main causes and evaluated the conduct adopted by students and their reactions and thoughts concerning the accidents. Seventy-two accidents were identified, of which 17% involved potentially contaminated biological material. Needles were the predominant cause of accidents. The most frequently involved topographic areas were the fingers. Only five students reported the accidents and sought medical care. Among these, two students were advised to begin prophylactic treatment against HIV infection by means of antiretroviral drugs. It was found that the risk of accidents is underestimated and that strategies such as formal teaching and continual training are necessary in order to make students aware of biosafety measures.

  19. Modelling effective dielectric properties of materials containing diverse types of biological cells

    International Nuclear Information System (INIS)

    Huclova, Sonja; Froehlich, Juerg; Erni, Daniel

    2010-01-01

    An efficient and versatile numerical method for the generation of different realistically shaped biological cells is developed. This framework is used to calculate the dielectric spectra of materials containing specific types of biological cells. For the generation of the numerical models of the cells a flexible parametrization method based on the so-called superformula is applied including the option of obtaining non-axisymmetric shapes such as box-shaped cells and even shapes corresponding to echinocytes. The dielectric spectra of effective media containing various cell morphologies are calculated focusing on the dependence of the spectral features on the cell shape. The numerical method is validated by comparing a model of spherical inclusions at a low volume fraction with the analytical solution obtained by the Maxwell-Garnett mixing formula, resulting in good agreement. Our simulation data for different cell shapes suggest that around 1MHz the effective dielectric properties of different cell shapes at different volume fractions significantly deviate from the spherical case. The most pronounced change exhibits ε eff between 0.1 and 1 MHz with a deviation of up to 35% for a box-shaped cell and 15% for an echinocyte compared with the sphere at a volume fraction of 0.4. This hampers the unique interpretation of changes in cellular features measured by dielectric spectroscopy when simplified material models are used.

  20. Certification of biological reference materials: participation of the Neutron Activation Laboratory (LAN-IPEN/CNEN-SP)

    International Nuclear Information System (INIS)

    Ticianelli, Regina B.; Figueiredo, Ana Maria G.

    2007-01-01

    Analytical laboratories have as one of their important goals to demonstrate their competence allowing international acceptance and comparison of analytical data. The IPEN Neutron Activation Laboratory (LAN-IPEN) has implemented its Quality Assurance Program which comprises, among other activities, the participation in intercomparison runs. As a part of this Quality Assurance Program, LAN-IPEN has participated in interlaboratorial trials to analyze two biological candidate reference materials: INCT-CF-3 Corn Flour and INCT-SBF-4 Soya Bean Flour from the Institute of Nuclear Chemistry And Technology (Warszawa, Poland). The elements Br, Ca, Co, Cs, Fe, K, Na, Rb and Zn were analyzed in the candidate reference materials by instrumental neutron activation analysis (INAA). The performance of the laboratory was statistically evaluated in relation to the consensus values for these materials using the Z-Score test. This laboratory evaluation method has been accepted as a standard by ISO/IUPAC. In the present study, adequate Z-Score values (|Z|<2) were observed for all of the analyzed elements, confirming the accuracy of the nuclear methodology employed. The contribution of LAN-IPEN in the certification of the reference materials analyzed was very important, since the results provided were used in the statistical evaluation of the certified value. (author)

  1. Communication of work accidents involving biological material: a study in the city of Santa Cruz do Sul/RS

    OpenAIRE

    Dayane Diehl; Karini da Rosa; Susimar Souza Rosa; Susane Beatriz Frantz Krug

    2012-01-01

    Rationale and Objectives: Healthcare workers are constantly exposed to the risk of occupational accidents involving biological material. Thus the aim of the study was to develop a profile of workers involved in workplace accidents with biological materials in Santa Cruz do Sul, through the number of notifications made in information systems. Methods: Transversal retrospective study with a quantitative approach; data collection was carried out between the years 2008 and 2010 from medical recor...

  2. Procurement of a Large Area Mapping FTIR Microscope for Organic-Inorganic Interfacial Analysis in Biological Materials

    Science.gov (United States)

    2015-12-31

    SECURITY CLASSIFICATION OF: After acquiring the Infrared Imaging Microscope with large area mapping capabilities for structure -function research and...Inorganic Interfacial Analysis in Biological Materials The views, opinions and/or findings contained in this report are those of the author(s) and should...of a Large Area Mapping FTIR Microscope for Organic-Inorganic Interfacial Analysis in Biological Materials Report Title After acquiring the Infrared

  3. Analytic determination of the activation of essential and toxic trace elements in biological material

    International Nuclear Information System (INIS)

    Schelenz, R.

    1980-01-01

    A neutron activation-analysis technique for the multielement determination in biological material was developed. The individual steps of this procedure comprise radiochemical and also instrumental analytic techniques. After radiochemical separation 34 elements can be determined, after only instrumental procedures 26 elements can be detected in biological material. The radiochemical analysis of 34 elements lasts 4 days. Tracer investigations on the radionuclide retention of the anorganic separators HAP, TiP and ZP in 9N aqueous HNO 3 solution indicated that apart from Na-24, K-42 and P-32 the radionuclides Cs-134, Rb-86 and Se-75 are almost quantitatively adsorbed at the separators. For the remaining investigated radionuclides different but well-reproducible retention values resulted. The pH-value only slightly influences the extent of the radionuclide retention. Kinetic investigations on the radiochemical precipitation of some radionuclides on Cu and Cu(Hg)sub(x) were carried out. The depositing of the radionuclides Ag-110m, Hg-203 and Se-75 at 0 0 C and room temperature on Cu(Hg)sub(x) and Cu foil is a first order reaction. The half-life periods and the velocity constants of the depositing on Cu and Cu(Hg)sub(x) were determined for the investigated radionuclides in dependency of the temperature. The technique was examined by means of international biological multielement standards of known element combinations. The realisation of ring tests for the multielement determination in potatoe and milk powder showed that this method provides precise results. The applicability of the radiochemical method was confirmed by the simultaneous determination of 25 elements in overall nutrition samples. The instrumental technique was applied for the multielement determination in human hair (of the head) and in river water. (orig./MG) [de

  4. Semiconductor Nanocrystals for Biological Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Aihua; Gu, Weiwei; Larabell, Carolyn; Alivisatos, A. Paul

    2005-06-28

    Conventional organic fluorophores suffer from poor photo stability, narrow absorption spectra and broad emission feature. Semiconductor nanocrystals, on the other hand, are highly photo-stable with broad absorption spectra and narrow size-tunable emission spectra. Recent advances in the synthesis of these materials have resulted in bright, sensitive, extremely photo-stable and biocompatible semiconductor fluorophores. Commercial availability facilitates their application in a variety of unprecedented biological experiments, including multiplexed cellular imaging, long-term in vitro and in vivo labeling, deep tissue structure mapping and single particle investigation of dynamic cellular processes. Semiconductor nanocrystals are one of the first examples of nanotechnology enabling a new class of biomedical applications.

  5. MEMS Tunable nanostructured photodetector

    DEFF Research Database (Denmark)

    Learkthanakhachon, Supannee

    This thesis was prepared at the department of Photonics Engineering, the Technical University of Denmark in fulfilment of the requirements for acquiring a Philosophiae doctor (Ph.D.) in Photonics Engineering. The thesis deals with the design and fabrication of tunable resonant-cavity-enhanced pho......) structure. Results from the fabricated devices are reported along with an investigation of the design parameters which influence the performance deviation from the design....

  6. Determination of tin in biological reference materials by atomic absorption spectrophotometry and neutron activation analysis

    International Nuclear Information System (INIS)

    Chiba, M.; Iyengar, V.; Gills, T.

    1991-01-01

    Because of a lack of reliable analytical techniques for the determination of tin in biological materials, there have been no reference materials certified for this element. However, the authors' experience has shown that it is feasible to use both atomic absorption and nuclear activation techniques at least for selected matrices. Therefore, an investigation was undertaken to determine tin in several biological materials such as non-fat milk powder (NBS-SRM-1549), citrus leaves (NBS-SRM-1572), total diet (NIST-SRM-1548), mixed diet (NBS-RM-8431), and USDIET-I by atomic absorption spectrophotometry (AAS) and neutron activation analysis (NAA). AAS-ashed samples were extracted with MIBK and assayed using a Perkin Elmer model 5000 apparatus. NAA was carried out by irradiating the samples at the NIST reactor in the RT-4 facility and counting with the help of a Ge(Li) detector connected to a multichannel analyzer. The concentration of tin measured by both AAS and NAA agree well for USDIET-I, total diet, citrus leaves and non-fat milk powder (the concentration ranges for tin in these matrices were from 0.0025 to 3.8 micro g/g). However, in the case of mixed diet (RM-8431), the mean values found were 47 ± 5.6 (n = 19) by AAS and 55.5 ± 2.5 (n = 6) by INAA. Since RM-8431 is not certified it is difficult to draw conclusions. For apple and peach leaves, a distillation step was required. The results were apple leaves 0.085 ± 0.015 (n = 10) by AAS and < 0.2 (n = 3) by RNAA; for peach leaves 0.077 ± 0.02 (n = 9) by AAS and < 0.1 (n = 3) by RNAA. All concentrations are expressed in micro g/g dry weight

  7. Effects of chemical and biological warfare remediation agents on the materials of museum objects

    Science.gov (United States)

    Solazzo, C.; Erhardt, D.; Marte, F.; von Endt, D.; Tumosa, C.

    In the fall of 2001, anthrax-contaminated letters were sent to public figures in the United States. Chemical and radiation treatments were employed to decontaminate exposed buildings, objects, and materials. These treatments are effective, but potentially damaging to exposed objects and materials. The recommended surface chemical treatments include solutions, gels, and foams of oxidizing agents such as peroxides or chlorine bleaching agents. Such oxidizing agents are effective against a wide range of hazardous chemical and biological agents. Knowing how these reagents affect various substrates would help to anticipate and to minimize any potential damage. We are examining the effects on typical museum materials of reagents likely to be used, including hydrogen peroxide, sodium hypochlorite, and potassium peroxymonosulfate. Results so far show significant changes in a number of materials. Surface corrosion was observed on metals such as copper, silver, iron, and brass. Color changes occurred with at least one reagent in about one-fourth of the dyed fabric swatches tested, and about half of the inks. Samples of aged yellowed paper are bleached. Effects varied with both the substrate and the tested reagent. The observed changes were generally less drastic than might have been expected. Enough materials were affected, though, to preclude the use of these reagents on museum objects unless no less drastic alternative is available. It appears that many objects of lesser intrinsic value can be treated without severe loss of properties or usefulness. For example, most documents should remain legible if the appropriate reagent is used. This work will provide a basis for determining which treatment is most appropriate for a specific situation and what consequences are to be expected from other treatments.

  8. Simultaneous determination of arsenic, copper, manganese, selenium, and zinc in biological materials by neutron activation analysis

    International Nuclear Information System (INIS)

    Damsgaard, E.; Heydorn, K.

    1976-08-01

    A method for the simultaneous determination of arsenic, copper, manganese, selenium, and zinc in biological material was developed by the incorporation of separation procedures for copper and zinc into an existing procedure. Investigation of the performance characteristics of the method was carried out with reference to copper and zinc. For certain materials characterized by a high Cu/Zn ratio, or a high zinc content, or both, such as liver, copper ihterferes in the determination of zinc thus requiring a small correction by an iterative procedure. Blank values for copper depend on the rinsing of the irradiation container, and a single rinsing with redistilled water was found superior to other rinsing procedures. Nuclear interference was negligible. The accuracy of the method was checked by analysis of Standard Reference Materials and the precision verified by analysis of Intercomparison Samples. Results are presented for 5 male foetuses of 3-5 months' gestational age. The distribution of arsenic, manganese and selenium is similar to that previously reported for adults. With the exception of liver, concentrations of copper in foetal organs were lower than values in the literature indicate. (author)

  9. Occupational exposure to contaminated biological material: perceptions and feelings experienced among dental students

    Directory of Open Access Journals (Sweden)

    Camila PINELLI

    Full Text Available INTRODUCTION: Dental students may be a particularly vulnerable group exposed to the risk of acquiring infections through occupational injuries.OBJECTIVE: To investigate the perceptions with regard to their occupational exposure to potentially infectious biologic materials.MATERIAL AND METHOD: Interviews were conducted by means of a script with open questions. The speeches were recorded, transcribed and qualitative analysis was performed with the aid of QUALIQUANTISOFT® software. The Collective Subject Discourse (CSD was obtained.RESULT: The feeling most frequently experienced was related to the fear of contagion. Most accidents occurred during the handling of sharp dental instruments. Respondents attributed the occurrence of accidents especially the lack of attention, carelessness while handling sharp instruments, and lack of use of Personal Protective Equipment. As regards the measures taken right after the exposure, they "washed the local area". Other respondents reported they "continued the dental treatment". They complained mostly about the fear of having been infected, and because they had to leave the faculty to take blood exams for HIV screening. As part of the learning experience the injured reported they paid more attention when handling sharp instruments. The students informed that any type of injury due to contact with contaminated material must be notified. However, they were neglectful about reporting their own injury.CONCLUSION: Education strategies for preventive measures related to occupational exposure must be restructured, because the knowledge and the fear of contagion among dental students were not always sufficient for a complete adherence to treatment protocols and notification.

  10. Tunable conductivity in mesoporous germanium

    Science.gov (United States)

    Beattie, Meghan N.; Bioud, Youcef A.; Hobson, David G.; Boucherif, Abderraouf; Valdivia, Christopher E.; Drouin, Dominique; Arès, Richard; Hinzer, Karin

    2018-05-01

    Germanium-based nanostructures have attracted increasing attention due to favourable electrical and optical properties, which are tunable on the nanoscale. High densities of germanium nanocrystals are synthesized via electrochemical etching, making porous germanium an appealing nanostructured material for a variety of applications. In this work, we have demonstrated highly tunable electrical conductivity in mesoporous germanium layers by conducting a systematic study varying crystallite size using thermal annealing, with experimental conductivities ranging from 0.6 to 33 (×10‑3) Ω‑1 cm‑1. The conductivity of as-prepared mesoporous germanium with 70% porosity and crystallite size between 4 and 10 nm is shown to be ∼0.9 × 10‑3 Ω‑1 cm‑1, 5 orders of magnitude smaller than that of bulk p-type germanium. Thermal annealing for 10 min at 400 °C further reduced the conductivity; however, annealing at 450 °C caused a morphological transformation from columnar crystallites to interconnecting granular crystallites and an increase in conductivity by two orders of magnitude relative to as-prepared mesoporous germanium caused by reduced influence of surface states. We developed an electrostatic model relating the carrier concentration and mobility of p-type mesoporous germanium to the nanoscale morphology. Correlation within an order of magnitude was found between modelled and experimental conductivities, limited by variation in sample uniformity and uncertainty in void size and fraction after annealing. Furthermore, theoretical results suggest that mesoporous germanium conductivity could be tuned over four orders of magnitude, leading to optimized hybrid devices.

  11. 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.

  12. 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.

  13. [Work accidents with biological material occurred in municipalities of Minas Gerais].

    Science.gov (United States)

    Julio, Renata Siqueira; Filardi, Monique Borsato Silva; Marziale, Maria Helena Palucci

    2014-01-01

    The study aimed to identify the profile accidents involving exposure to biological material occurring in Minas Gerais. A descriptive study carried out by querying the Information System for Notifiable Diseases, 50 cities in south of Minas Gerais State, Brazil, in the period of 2007-2011. Were recorded 460 accidents, and about half occurred among nursing assistants and technicians, followed by nurses and physicians. There were more accidents due to improper disposal of sharps. Among the source patients, there was a 8.0% prevalence of positive serology for HIV, 1.0% for HBsAg, 6.0% for anti-HBc and 3% for anti-HCV. Among the injured 14.0% were not immunized to hepatitis B; however, the vaccine and immunoglobulin prescription was lower than necessary. The results will subsidize the plan preventive measures and new approach towards the occurrence of such accidents.

  14. Why should we respect the privacy of donors of biological material?

    Science.gov (United States)

    Tännsjö, Torbjörn

    2011-02-01

    Why should we respect the privacy of donors of biological material? The question is answered in the present article in general philosophical terms from the point of view of an ethics of honour, a libertarian theory of rights, a view of respect for privacy based on the idea that autonomy is of value in itself, and utilitarianism respectively. For different reasons the ethics of honour and the idea of the value of autonomy are set to one side. It surfaces that the moral rights theory and utilitarianism present conflicting answers to the question. The main thrust of the argument is that there is no way of finding an overlapping consensus, so politicians have to take decisions that are bound to be controversial in that they can be questioned on reasonable philosophical grounds.

  15. Ultratrace determination of platinum in biological materials via neutron activation and radiochemical separation

    International Nuclear Information System (INIS)

    Zeisler, R.; Greenberg, R.R.

    1982-01-01

    A neutron activation analysis scheme based upon a radiochemical separation of the activation products has been developed. The method utilizes the inherent sensitivity of the activation reaction 198 Pt(n,ν) 199 Pt and counting of the daughter nuclide 199 Au. This nuclide is radiochemically separated from interfering activities by homogeneous precipitation as elemental gold. The remaining interference of the secondary reaction 197 Au(n,ν) 198 Au(n,ν) 199 Au from gold in the samples is quantitatively assessed and corrected. During this process accurate gold concentrations in the samples are obtained at ultratrace levels. The analysis scheme is applied to gold and platinum determinations in biological Standard Reference Materials and human liver specimens. Gold and platinum are determined at concentrations of 5x10 - 11 g/g, and at higher levels. (author)

  16. Activation analytical determination of essential and toxic trace elements in biological material

    International Nuclear Information System (INIS)

    Schelenz, R.

    1980-01-01

    In order to determine the essential trace elements Hg, Ag, Cu and Se in food (potatoes, milk powder) and biological standard materials (fruit tree leaves), simple, fast radiochemical separation methods are worked out. Following oxidative decomposition and destillation of Hg, the elements silver, copper and selenium are found in the destillation residue and can be electrochemically enriched on an amalgamated Cu foil (determination of Ag and Se in the concentration range of 10 -9 to 10 -8 g, of Cu in the range of 10 -12 to 10 -10 g), whilst the matrix elements Na, K, P are adsorbed on a column with 3 different inorganic ion exchangers. The eluate of the ion exchanger can be added directly to the multielement gamma spectroscopy. The possiblity of working purely instrumentally is demonstrated by 2 examples: multielement analysis of human hair and river water. (RB) [de

  17. A rapid screening method for heavy metals in biological materials by emission spectroscopy.

    Science.gov (United States)

    Blacklock, E C; Sadler, P A

    1981-06-02

    A semi-quantitative screening method for heavy metals in biological material is described. The metals are complexed with ammonium pyrrolidine dithiocarbamate, sodium diethyl dithiocarbamate and potassium sodium tartrate. The solutions are adjusted to pH 4 and then extracted into chloroform. The chloroform phase is evaporated onto a matrix mixture of lithium fluoride and graphite. The sample is analysed by direct current arc emission spectroscopy using a 3 metre grating spectrograph. The spectra are recorded on a photographic plate. The method is developed on aqueous and spiked samples and then applied to in vivo samples containing toxic levels of heavy metals. Atomic absorption spectroscopy is used to check standard concentrations and to monitor the efficiency of the extraction procedure.

  18. Reactivity comparison of biological material after radiolabeling with avidin-biotin system

    International Nuclear Information System (INIS)

    Fan Wo; Qian Jianhua; Zhu Benxing

    2003-01-01

    To find a method for determining the immunoreactivity of monoclonal antibodies after radiolabeling avidin is unlabeled and labeled with Rodamine, 131 I and 188 Re, respectively. The affinities and half-desorbed amounts of biotin and four kinds of avidin are determined by the biotin columns plus non-labeled avidin (cold avidin). The affinities of biotin and avidin unlabeled and labeled with Rodamine, 188 Re and 131 I are decreased in turn. Their half-desorbed amounts from biotin are 21.9, 19.5, 25.7 and 47.9 μg of cold avidin. Two kinds of radiolabeled avidin have lower affinity with biotin than that of avidin unlabeled and labeled with Rodamine. There is a possibility to evaluate the reactivity of biological materials with different labeling methods by avidin-biotin system

  19. Determination of selenium in biological material by instrumental neutron activation analysis using 77m Se radioisotope

    International Nuclear Information System (INIS)

    Vasconcellos, Marina B.A.; Moreira, Edson G.; Catharino, Marilia G.M.; Tokura, Alexandra M.; Saiki, Mitiko

    1999-01-01

    Selenium is an essential element in human diet due to its relation to the protection against carcinogenic substances, heart disease, hypertension, sexual performance enhancement, and others. In this work Se concentration in samples of the biological certificate reference materials Human Hair BCR-CRM 397, Spiked Human Hair IAEA-085, Unspiked Human Hair IAEA-086; Dogfish Liver DOLT-1 and Dogfish Muscle DORM-1 were determined in order to improve the instrumental neutron activation analysis, INAA, method using 77m Se radioisotope. The application of this method allows the analysis of a large number of samples of samples with reduced time of experimental and cost. the best results were obtained with the reactor operating at 5 MW and time of irradiation between 10 and 20 s. In these experimental conditions the relative standard deviation and error were generally lower than 10%. (author)

  20. Method for determination of radioactive iodine isotopes in environmental objects and biologic materials

    International Nuclear Information System (INIS)

    Dubynin, O.D.; Pogodin, R.I.

    1981-01-01

    The method proposed for determination of radioactive iodine isotopes content in environmental objects and biologic materials is based on the extraction of iodine with carbon tetrachloride and subsequent precipitation of bismuthyl iodine (BiOI) in perchloric medium. Sample preparation for analysis is carried out using conventional alkaline ashing methods. Quantitative iodine separation is hampered if macroquantities of Cl - , Br - , SO 4 2 - , SO 8 2 - , Cr 2 O 7 2 - and other ions are present in the solution. Iodine extraction is carried out before its precipitation. Separated iodine preparation activity is measured using scintillation (NaI) Tl gamma spectrometer. The method's sensitivity when measuring iodine-131 preparations makes up 0.07 Bq per 1 sample with the error +-25 %

  1. Determination of zinc stable isotopes in biological materials using isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Patterson, K.Y.; Veillon, Claude

    1992-01-01

    A method is described for using isotope dilution to determine both the amount of natural zinc and enriched isotopes of zinc in biological samples. Isotope dilution inductively coupled plasma mass spectrometry offers a way to quantify not only the natural zinc found in a sample but also the enriched isotope tracers of zinc. Accurate values for the enriched isotopes and natural zinc are obtained by adjusting the mass count rate data for measurable instrumental biases. Analytical interferences from the matrix are avoided by extracting the zinc from the sample matrix using diethylammonium diethyldithiocarbamate. The extraction technique separates the zinc from elements which form interfering molecular ions at the same nominal masses as the zinc isotopes. Accuracy of the method is verified using standard reference materials. The detection limit is 0.06 μg Zn per sample. Precision of the abundance ratios range from 0.3-0.8%. R.S.D. for natural zinc concentrations is about 200-600 μg g -1 . The accuracy and precision of the measurements make it possible to follow enriched isotopic tracers of zinc in biological samples in metabolic tracer studies. (author). 19 refs.; 1 fig., 4 tabs

  2. Recovery of iodine as iodine-125 from biological materials prior to assay

    International Nuclear Information System (INIS)

    Jones, G.B.; Belling, G.B.; Buckley, R.A.

    1979-01-01

    In biological tissues iodine is usually present as iodoamino acids or iodoproteins. The organic material must be oxidised and the iodine converted into iodate prior to the final spectrophotometric determination. At parts per billion (10 9 ) levels, recoveries of added iodine are difficult to measure precisely as iodine can easily be lost from the sample and added inorganic iodine may not be recovered in the same proportions as the naturally occurring iodine. Iodine-125 provides a much more sensitive, specific and accurate means of testing the recovery of nanogram amounts of iodine from biological tissues and it can be incorporated into tissues in the naturally occurring compounds. Plants can be grown in a solution culture containing iodine-125 and animals can be injected with iodine-125 to provide tissues where naturally occurring iodine compounds are labelled with radioactive iodine. These tissues can be used to examine the recovery of iodine after oven drying, freeze drying, alkali ashing and acid digestion of the samples. Experimental details are given for spinach, tobacco, oats, cauliflower and thyroid. Results are given and discussed. (author)

  3. Measuring spatially- and directionally-varying light scattering from biological material.

    Science.gov (United States)

    Harvey, Todd Alan; Bostwick, Kimberly S; Marschner, Steve

    2013-05-20

    Light interacts with an organism's integument on a variety of spatial scales. For example in an iridescent bird: nano-scale structures produce color; the milli-scale structure of barbs and barbules largely determines the directional pattern of reflected light; and through the macro-scale spatial structure of overlapping, curved feathers, these directional effects create the visual texture. Milli-scale and macro-scale effects determine where on the organism's body, and from what viewpoints and under what illumination, the iridescent colors are seen. Thus, the highly directional flash of brilliant color from the iridescent throat of a hummingbird is inadequately explained by its nano-scale structure alone and questions remain. From a given observation point, which milli-scale elements of the feather are oriented to reflect strongly? Do some species produce broader "windows" for observation of iridescence than others? These and similar questions may be asked about any organisms that have evolved a particular surface appearance for signaling, camouflage, or other reasons. In order to study the directional patterns of light scattering from feathers, and their relationship to the bird's milli-scale morphology, we developed a protocol for measuring light scattered from biological materials using many high-resolution photographs taken with varying illumination and viewing directions. Since we measure scattered light as a function of direction, we can observe the characteristic features in the directional distribution of light scattered from that particular feather, and because barbs and barbules are resolved in our images, we can clearly attribute the directional features to these different milli-scale structures. Keeping the specimen intact preserves the gross-scale scattering behavior seen in nature. The method described here presents a generalized protocol for analyzing spatially- and directionally-varying light scattering from complex biological materials at multiple

  4. Biological evaluation of a new pulp capping material developed from Portland cement.

    Science.gov (United States)

    Negm, Ahmed M; Hassanien, Ehab E; Abu-Seida, Ashraf M; Nagy, Mohamed M

    2017-03-02

    This study evaluates the biological properties of a new pulp capping material developed from Portland cement. This study was conducted on 48 teeth in 4 dogs (12 teeth/dog). The dogs were classified into two equal groups (n=24 teeth) according to the evaluation period including: group A (3 weeks) and group B (3 months). Each group was further subdivided into three equal subgroups (n=8 teeth) according to the capping material including: subgroup 1: mineral trioxide aggregate (MTA), subgroup2: Portland cement+10% calcium hydroxide+20% bismuth oxide (Port Cal) and subgroup 3: Portland cement+bismuth oxide. After general anesthesia, a class V buccal cavity was prepared coronal to the gingival margin. After pulp exposure and hemostasis,the capping materials and glass ionomer filling were placed on the exposure sites. All histopathological findings, inflammatory cell count and dentin bridge formation were recorded. Data were analyzed statistically. After 3 months, the histopathological picture of the pulp in subgroup 1 showed normal pulp, continuous odontoblastic layer and complete dentin bridge formation while subgroup 2 showed partial and complete dentin bridge over a normal and necrotic pulps. Subgroup 3 showed loss of normal architecture, areas of necrosis, complete, or incomplete dentin bridge formation, attached and detached pulp stones and fatty degeneration in group B. For group A, MTA subgroup showed the least number of inflammatory cell infiltrate followed by Port Cal subgroup. While subgroup 3 showed the highest number of inflammatory cell infiltrate. For group B, the mean inflammatory cell count increased with the three tested materials with no statistical difference. Regarding dentin bridge formation at group A, no significant differences was found between subgroups, while at group B, MTA subgroup exhibited significantly higher scores than other subgroups. In conclusion, addition of calcium hydroxide to Portland cement improves the dentin bridge formation

  5. Radiation distribution through serpentine concrete using local materials and its application as a reactor biological shield

    International Nuclear Information System (INIS)

    Kansouh, W.A.

    2012-01-01

    Highlights: ► New serpentine concrete was made and examined as a reactor biological shield. ► Ilmenite–limonite concrete is a better reactor biological shield. ► New serpentine concrete is a better reactor fast neutrons shield than ordinary and hematite–serpentine concretes. ► Serpentine concrete has lower properties as a reactor total gamma rays shields. - Abstract: In the present work attempt has been made to estimate the shielding parameters of the new serpentine concrete (density = 2.4 g/cm 3 ) using local materials on the shielding parameters for two types of heat resistant concretes, namely hematite–serpentine (density = 2.5 g/cm 3 ) and ilmenite–limonite (density = 2.9 g/cm 3 ). Shielding parameters for ordinary concrete (density = 2.3 g/cm 3 ) were also discussed. These parameters were determined experimentally for serpentine concrete and compared with previously published values for other concretes, which had also been obtained using local materials. The leakage spectra of reactor fast neutrons and total gamma photon beams from cylindrical samples of these concrete shields were also investigated using a collimated beam from ET-RR-1 reactor. A neutron–gamma spectrometer was used in order to obtain pulse height spectra of reactor fast neutrons and the total gamma rays leakage through the investigated concrete samples. These spectra were utilized to obtain the energy spectra required in these investigations. Removal cross section Σ R (E n ) and linear attenuation coefficient μ(E g ) for reactor fast neutrons and total gamma rays and their relative coefficients were evaluated and presented. Measured results were compared with those previously measured for other concretes. The results show that ilmenite–limonite concrete is a better reactor biological shield than the other three concretes. Serpentine concrete under investigation is a better reactor fast neutrons shield than ordinary and hematite–serpentine concretes. Serpentine concrete

  6. Tunable Nitride Josephson Junctions.

    Energy Technology Data Exchange (ETDEWEB)

    Missert, Nancy A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Henry, Michael David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lewis, Rupert M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Howell, Stephen W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wolfley, Steven L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brunke, Lyle Brent [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wolak, Matthaeus [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    We have developed an ambient temperature, SiO2/Si wafer - scale process for Josephson junctions based on Nb electrodes and Ta x N barriers with tunable electronic properties. The films are fabricated by magnetron sputtering. The electronic properties of the TaxN barriers are controlled by adjusting the nitrogen flow during sputtering. This technology offers a scalable alternative to the more traditional junctions based on AlOx barriers for low - power, high - performance computing.

  7. Effects of addictive substances during pregnancy and infancy and their analysis in biological materials.

    Science.gov (United States)

    Płotka, Justyna; Narkowicz, Sylwia; Polkowska, Zaneta; Biziuk, Marek; Namieśnik, Jacek

    2014-01-01

    The use of addictive substances during pregnancy is a serious social problem, not only because of effects on the health of the woman and child, but also because drug or alcohol dependency detracts from child care and enhances the prospect of child neglect and family breakdown. Developing additive substance abuse treatment programs for pregnant women is socially important and can help ensure the health of babies, prevent subsequent developmental and behavioral problems (i.e., from intake of alcohol or other additive substances such as methamphetamine, cocaine,or heroine) and can reduce addiction costs to society. Because women of childbearing age often abuse controlled substances during their pregnancy, it is important to undertake biomonitoring of these substances in biological samples taken from the pregnant or nursing mother (e.g., blood, urine,hair, breast milk, sweat, oral fluids, etc.), from the fetus and newborn (e.g., meconium,cord blood, neonatal hair and urine) and from both the mother and fetus (i.e.,amniotic fluids and placenta). The choice of specimens to be analyzed is determined by many factors; however, the most important is knowledge of the chemical and physical characteristics of a substance and the route of it administration. Maternal and neonatal biological materials reflect exposures that occur over a specific time period, and each of these biological specimens has different advantages and disadvantages,in terms of accuracy, time window of exposure and cost/benefit ratio.Sampling the placenta may be the most important biomonitoring choice for assessing in utero exposure to addictive substances. The use of the placenta in scientific research causes a minimum of ethical problems, partly because its sampling is noninvasive, causes no harm to mother or child, and partly because, in any case,placentas are discarded and incinerated after birth. Such samples, when properly analyzed, may provide key essential information about fetal exposure to toxic

  8. Determination of copper in biological materials by neutron activation analysis using short-lived 66Cu

    International Nuclear Information System (INIS)

    Dybczynski, R.; Danko, B.; Kaczorowski, J.

    1989-01-01

    A method for determination of copper traces in biological materials based on neutron activation employing 65 Cu(n, γ) 66 Cu reaction and preconcentration by extraction chromatography has been devised. The 200-500 mg samples after wet digestion and evaporation were dissolved in glycine solution and after pH adjusting to ca. 4.4 were passed through the column with Lix 64N on Bio Beads SM-1 for isolation of copper traces from the matrix elements. Other cations were selectively eluted with 0.1 mol x 1 -1 (glycine-HNO 3 ) buffer, 1 mol x 1 -1 in NH 4 NO 3 (pH = 3.6). The resin bed with quantitatively retained copper was sealed in the PE bag and irradiated together with Cu standards in EWA reactor using pneumatic tube facility. The activity of the short-lived 66 Cu was measured in samples and standard by gamma-ray spectrometry with Ge(Li) detector. Good accuracy of the method was confirmed by analysis of the following certified reference materials: NBS 1571 Orchad leaves, IAEA H-4 Animal muscle, IAEA V-8 Rye flour, IAEA A-11 milk powder. The detection limit amounted to 0.34 mg/kg, for the sample weight of 500 mg. (author)

  9. Evaluation of radiochemical neutron activation analysis methods for determination of arsenic in biological materials.

    Science.gov (United States)

    Paul, Rick L

    2011-01-01

    Radiochemical neutron activation analysis (RNAA) with retention on hydrated manganese dioxide (HMD) has played a key role in the certification of As in biological materials at NIST. Although this method provides very high and reproducible yields and detection limits at low microgram/kilogram levels, counting geometry uncertainties may arise from unequal distribution of As in the HMD, and arsenic detection limits may not be optimal due to significant retention of other elements. An alternate RNAA procedure with separation of arsenic by solvent extraction has been investigated. After digestion of samples in nitric and perchloric acids, As(III) is extracted from 2 M sulfuric acid solution into a solution of zinc diethyldithiocarbamate in chloroform. Counting of (76)As allows quantitation of arsenic. Addition of an (77)As tracer solution prior to dissolution allows correction for chemical yield and counting geometries, further improving reproducibility. The HMD and solvent extraction procedures for arsenic were compared through analysis of SRMs 1577c (bovine liver), 1547 (peach leaves), and 1575a (pine needles). Both methods gave As results in agreement with certified values with comparable reproducibility. However, the solvent extraction method yields a factor of 3 improvement in detection limits and is less time-consuming than the HMD method. The new method shows great promise for use in As certification in reference materials.

  10. [Determinant factors and conduct in post-accident with biological material among pre-hospital professionals].

    Science.gov (United States)

    Paiva, Maria Henriqueta Rocha Siqueira; Oliveira, Adriana Cristina

    2011-01-01

    This transversal study was carried out with a multiprofessional team in the pre-hospital care in Minas Gerais, Brazil. It aimed to estimate the incidence of occupational accidents by exposure to biological material and post-accidents conductsta. Descriptive analysis and logistic regression were used. Incidence of accidents was 19.8%: 39,1% perforating-cutting materials and 56.5% body fluids. Doctors (33.3%) and drivers (24.0%) were most involved. Inadequate subsequent measures were highly prevalent: no medical assessment (69.6%), no work accident communication issued (91.3%), no measures (52.2%) and no serological follow-up (52.2%). Variables associated with accidents were: age >31 years old (OR = 3,02; IC95%: 1,25 - 7,33; p = 0,014) and working in basic support units (OR = 5,36; IC95%: 1,51 19,08; p = 0,010). The implementation of post-accidents protocols is suggested in order to reduce accidents and under-notification, and increase post-accident follow-up.

  11. Water regime of mechanical-biological pretreated waste materials under fast-growing trees.

    Science.gov (United States)

    Rüth, Björn; Lennartz, Bernd; Kahle, Petra

    2007-10-01

    In this study mechanical-biological pre-treated waste material (MBP) was tested for suitability to serve as an alternative surface layer in combination with fast-growing and water-consumptive trees for final covers at landfill sites. The aim was to quantify evapotranspiration and seepage losses by numerical model simulations for two sites in Germany. In addition, the leaf area index (LAI) of six tree species over the growing season as the driving parameter for transpiration calculations was determined experimentally. The maximum LAI varied between 3.8 and 6.1 m2 m(-2) for poplar and willow clones, respectively. The evapotranspiration calculations revealed that the use of MBP waste material for re-cultivation enhanced evapotranspiration by 40 mm year(-1) (10%) over an 11 year calculation period compared to a standard mineral soil. Between 82% (for LAI(max) = 3.8) and 87% (for LAI(max) = 6.1) of the average annual precipitation (506 mm) could be retained from the surface layer assuming eastern German climate conditions, compared with a retention efficiency between 79 and 82% for a mineral soil. Although a MBP layer in conjunction with water-consumptive trees can reduce vertical water losses as compared to mineral substrates, the effect is not sufficient to meet legal regulations.

  12. Propulsion of swimming microrobots inspired by metachronal waves in ciliates: from biology to material specifications

    International Nuclear Information System (INIS)

    Palagi, Stefano; Mazzolai, Barbara; Beccai, Lucia; Jager, Edwin WH

    2013-01-01

    The quest for swimming microrobots originates from possible applications in medicine, especially involving navigation in bodily fluids. Swimming microorganisms have become a source of inspiration because their propulsion mechanisms are effective in the low-Reynolds number regime. In this study, we address a propulsion mechanism inspired by metachronal waves, i.e. the spontaneous coordination of cilia leading to the fast swimming of ciliates. We analyse the biological mechanism (referring to its particular embodiment in Paramecium caudatum), and we investigate the contribution of its main features to the swimming performance, through a three-dimensional finite-elements model, in order to develop a simplified, yet effective artificial design. We propose a bioinspired propulsion mechanism for a swimming microrobot based on a continuous cylindrical electroactive surface exhibiting perpendicular wave deformations travelling longitudinally along its main axis. The simplified propulsion mechanism is conceived specifically for microrobots that embed a micro-actuation system capable of executing the bioinspired propulsion (self-propelled microrobots). Among the available electroactive polymers, we select polypyrrole as the possible actuation material and we assess it for this particular embodiment. The results are used to appoint target performance specifications for the development of improved or new electroactive materials to attain metachronal-waves-like propulsion. (paper)

  13. Propulsion of swimming microrobots inspired by metachronal waves in ciliates: from biology to material specifications.

    Science.gov (United States)

    Palagi, Stefano; Jager, Edwin W H; Mazzolai, Barbara; Beccai, Lucia

    2013-12-01

    The quest for swimming microrobots originates from possible applications in medicine, especially involving navigation in bodily fluids. Swimming microorganisms have become a source of inspiration because their propulsion mechanisms are effective in the low-Reynolds number regime. In this study, we address a propulsion mechanism inspired by metachronal waves, i.e. the spontaneous coordination of cilia leading to the fast swimming of ciliates. We analyse the biological mechanism (referring to its particular embodiment in Paramecium caudatum), and we investigate the contribution of its main features to the swimming performance, through a three-dimensional finite-elements model, in order to develop a simplified, yet effective artificial design. We propose a bioinspired propulsion mechanism for a swimming microrobot based on a continuous cylindrical electroactive surface exhibiting perpendicular wave deformations travelling longitudinally along its main axis. The simplified propulsion mechanism is conceived specifically for microrobots that embed a micro-actuation system capable of executing the bioinspired propulsion (self-propelled microrobots). Among the available electroactive polymers, we select polypyrrole as the possible actuation material and we assess it for this particular embodiment. The results are used to appoint target performance specifications for the development of improved or new electroactive materials to attain metachronal-waves-like propulsion.

  14. Optimal design of tunable phononic bandgap plates under equibiaxial stretch

    International Nuclear Information System (INIS)

    Hedayatrasa, Saeid; Abhary, Kazem; Uddin, M S; Guest, James K

    2016-01-01

    Design and application of phononic crystal (PhCr) acoustic metamaterials has been a topic with tremendous growth of interest in the last decade due to their promising capabilities to manipulate acoustic and elastodynamic waves. Phononic controllability of waves through a particular PhCr is limited only to the spectrums located within its fixed bandgap frequency. Hence the ability to tune a PhCr is desired to add functionality over its variable bandgap frequency or for switchability. Deformation induced bandgap tunability of elastomeric PhCr solids and plates with prescribed topology have been studied by other researchers. Principally the internal stress state and distorted geometry of a deformed phononic crystal plate (PhP) changes its effective stiffness and leads to deformation induced tunability of resultant modal band structure. Thus the microstructural topology of a PhP can be altered so that specific tunability features are met through prescribed deformation. In the present study novel tunable PhPs of this kind with optimized bandgap efficiency-tunability of guided waves are computationally explored and evaluated. Low loss transmission of guided waves throughout thin walled structures makes them ideal for fabrication of low loss ultrasound devices and structural health monitoring purposes. Various tunability targets are defined to enhance or degrade complete bandgaps of plate waves through macroscopic tensile deformation. Elastomeric hyperelastic material is considered which enables recoverable micromechanical deformation under tuning finite stretch. Phononic tunability through stable deformation of phononic lattice is specifically required and so any topology showing buckling instability under assumed deformation is disregarded. Nondominated sorting genetic algorithm (GA) NSGA-II is adopted for evolutionary multiobjective topology optimization of hypothesized tunable PhP with square symmetric unit-cell and relevant topologies are analyzed through finite

  15. Mitigating the risk of Zika virus contamination of raw materials and cell lines in the manufacture of biologicals.

    Science.gov (United States)

    Zmurko, Joanna; Vasey, Douglas B; Donald, Claire L; Armstrong, Alison A; McKee, Marian L; Kohl, Alain; Clayton, Reginald F

    2018-02-01

    Ensuring the virological safety of biologicals is challenging due to the risk of viral contamination of raw materials and cell banks, and exposure during in-process handling to known and/or emerging viral pathogens. Viruses may contaminate raw materials and biologicals intended for human or veterinary use and remain undetected until appropriate testing measures are employed. The outbreak and expansive spread of the mosquito-borne flavivirus Zika virus (ZIKV) poses challenges to screening human- and animal -derived products used in the manufacture of biologicals. Here, we report the results of an in vitro study where detector cell lines were challenged with African and Asian lineages of ZIKV. We demonstrate that this pathogen is robustly detectable by in vitro assay, thereby providing assurance of detection of ZIKV, and in turn underpinning the robustness of in vitro virology assays in safety testing of biologicals.

  16. Super-paramagnetic core-shell material with tunable magnetic behavior by regulating electron transfer efficiency and structure stability of the shell

    Directory of Open Access Journals (Sweden)

    Wenyan Zhang

    Full Text Available In this work, a spherical nano core-shell material was constructed by encapsulating Fe3O4 microsphere into conductive polymer-metal composite shell. The Fe3O4 microspheres were fabricated by assembling large amounts of Fe3O4 nano-crystals, which endowed the microspheres with super-paramagnetic property and high saturation magnetization. The polymer-metal composite shell was constructed by inserting Pt nano-particles (NPs into the conductive polymer polypyrrole (PPy. As size and dispersion of the Pt NPs has an important influence on their surface area and surface energy, it was effective to enlarge the interface area between PPy and Pt NPs, enhance the electron transfer efficiency of PPy/Pt composite shell, and reinforced the shell’s structural stability just by tuning the size and dispersion of Pt NPs. Moreover, core-shell structure of the materials made it convenient to investigate the PPy/Pt shell’s shielding effect on the Fe3O4 core’s magnetic response to external magnetic fields. It was found that the saturation magnetization of Fe3O4/PPy/Pt core-shell material could be reduced by 20.5% by regulating the conductivity of the PPy/Pt shell. Keywords: Super-paramagnetic, Conductivity, Magnetic shielding, Structural stability

  17. Tunable Topological Phononic Crystals

    KAUST Repository

    Chen, Zeguo; Wu, Ying

    2016-01-01

    Topological insulators first observed in electronic systems have inspired many analogues in photonic and phononic crystals in which remarkable one-way propagation edge states are supported by topologically nontrivial band gaps. Such band gaps can be achieved by breaking the time-reversal symmetry to lift the degeneracy associated with Dirac cones at the corners of the Brillouin zone. Here, we report on our construction of a phononic crystal exhibiting a Dirac-like cone in the Brillouin zone center. We demonstrate that simultaneously breaking the time-reversal symmetry and altering the geometric size of the unit cell result in a topological transition that we verify by the Chern number calculation and edge-mode analysis. We develop a complete model based on the tight binding to uncover the physical mechanisms of the topological transition. Both the model and numerical simulations show that the topology of the band gap is tunable by varying both the velocity field and the geometric size; such tunability may dramatically enrich the design and use of acoustic topological insulators.

  18. Tunable Topological Phononic Crystals

    KAUST Repository

    Chen, Zeguo

    2016-05-27

    Topological insulators first observed in electronic systems have inspired many analogues in photonic and phononic crystals in which remarkable one-way propagation edge states are supported by topologically nontrivial band gaps. Such band gaps can be achieved by breaking the time-reversal symmetry to lift the degeneracy associated with Dirac cones at the corners of the Brillouin zone. Here, we report on our construction of a phononic crystal exhibiting a Dirac-like cone in the Brillouin zone center. We demonstrate that simultaneously breaking the time-reversal symmetry and altering the geometric size of the unit cell result in a topological transition that we verify by the Chern number calculation and edge-mode analysis. We develop a complete model based on the tight binding to uncover the physical mechanisms of the topological transition. Both the model and numerical simulations show that the topology of the band gap is tunable by varying both the velocity field and the geometric size; such tunability may dramatically enrich the design and use of acoustic topological insulators.

  19. Electrothermally Tunable Arch Resonator

    KAUST Repository

    Hajjaj, Amal Z.

    2017-03-18

    This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of electrothermally actuated microelectromechanical arch beams. The beams are made of silicon and are intentionally fabricated with some curvature as in-plane shallow arches. An electrothermal voltage is applied between the anchors of the beam generating a current that controls the axial stress caused by thermal expansion. When the electrothermal voltage increases, the compressive stress increases inside the arch beam. This leads to an increase in its curvature, thereby increasing its resonance frequencies. We show here that the first resonance frequency can increase monotonically up to twice its initial value. We show also that after some electrothermal voltage load, the third resonance frequency starts to become more sensitive to the axial thermal stress, while the first resonance frequency becomes less sensitive. These results can be used as guidelines to utilize arches as wide-range tunable resonators. Analytical results based on the nonlinear Euler Bernoulli beam theory are generated and compared with the experimental data and the results of a multi-physics finite-element model. A good agreement is found among all the results. [2016-0291

  20. [Care and specialized clinical follow-up of nursing professionals who have been victims of accidents with biological material].

    Science.gov (United States)

    Pimenta, Flaviana Regina; Ferreira, Milene Dias; Gir, Elucir; Hayashida, Miyeko; Canini, Silvia Rita Marin da Silva

    2013-02-01

    This cross-sectional study aimed to evaluate the conduct of nursing professionals who had been victims of accidents with biological material in a teaching hospital in the interior of the state of São Paulo, Brazil, regarding their care and specialized clinical follow-up. The study population consisted of 1,215 nursing professionals, who were interviewed individually between 2010 and 2011. Of the 1,215 nursing professionals interviewed, 636 (52.3%) reported having experienced accidents with biological material; of this population, 182 (28.6%) didn't sought specialized care. The most frequent reason reported for not seeking care was believing that it was a low-risk accident. The reasons professionals do not seek care and do not complete treatment and the clinical follow-up can contribute to strategies to increase professionals' adherence to prophylaxis measures after occupational exposure to biological material.

  1. Environmental routes for platinum group elements to biological materials. A review

    Energy Technology Data Exchange (ETDEWEB)

    Ek, Kristine H.; Morrison, Gregory M. [Water Environment Transport, Chalmers University of Technology, SE 412 96 Goteborg (Sweden); Rauch, Sebastien [R.M. Parsons Laboratory 48-108, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2004-12-01

    The increased use of platinum group elements (PGE) in automobile catalysts has led to concern over potential environmental and biological accumulation. Platinum (Pt), palladium (Pd) and rhodium (Rh) concentrations have increased in the environment since the introduction of automobile catalysts. This review summarises current knowledge concerning the environmental mobility, speciation and bioavailability of Pt, Pd and Rh. The greater proportion of PGE emissions is from automobile catalysts, in the form of nanometer-sized catalyst particles, which deposit on roadside surfaces, as evidenced in samples of road dust, grass and soil. In soil, PGE can be transformed into more mobile species through complexation with organic matter and can be solubilised in low pH rainwater. There are indications that environmentally formed Pd species are more soluble and hence more mobile in the environment than Rh and Pt. PGE can reach waterbodies through stormwater transport and deposition in sediments. Besides external contamination of grass close to roads, internal PGE uptake has been observed for plants growing on soil contaminated with automobile catalyst PGE. Fine particles of PGE were also detected on the surface of feathers sampled from passerines and raptors in their natural habitat, and internal organs of these birds also contained PGE. Uptake has been observed in sediment-dwelling invertebrates, and laboratory studies have shown an uptake of PGE in eel and fish exposed to water containing road dust.The available evidence indicates that the PGE, especially Pd, are transported to biological materials through deposition in roots by binding to sulphur-rich low molecular weight species in plants. PGE uptake to exposed animals have uptake rates in the following order: Pd>Pt>Rh. The liver and kidney accumulate the highest levels of PGE, especially Pd. Urinary Pd and Rh, but not Pt, levels are correlated with traffic intensity. Dental alloys may lead to elevated urinary Pt levels

  2. Double lens device for tunable harmonic generation of laser beams in KBBF/RBBF crystals or other non-linear optic materials

    Science.gov (United States)

    Kaminski, Adam

    2017-08-22

    A method and apparatus to generate harmonically related laser wavelengths includes a pair of lenses at opposing faces of a non-linear optical material. The lenses are configured to promote incoming and outgoing beams to be normal to each outer lens surface over a range of acceptance angles of the incoming laser beam. This reduces reflection loss for higher efficiency operation. Additionally, the lenses allow a wider range of wavelengths for lasers for more universal application. Examples of the lenses include plano-cylindrical and plano-spherical form factors.

  3. Co_3V_2O_8 Hexagonal Pyramid with Tunable Inner Structure as High Performance Anode Materials for Lithium Ion Battery

    International Nuclear Information System (INIS)

    Zhang, Qiang; Pei, Jian; Chen, Gang; Bie, Changfeng; Chen, Dahong; Jiao, Yang; Rao, Jiancun

    2017-01-01

    Co_3V_2O_8 hexagonal pyramid was successfully fabricated via a simple hydrothermal process and subsequent heat treatment. The inner structure of the hexagonal pyramid was further adjusted by controlling the size of Co_7V_4O_1_6(OH)_2(H_2O) precursors. Hierarchical Co_3V_2O_8 hexagonal pyramid with height of 1 μm were orderly constructed from 60–80 nm inter-connected particles, showing numerous interval voids. Benefiting from its unique structure, the as-prepared sample showed higher electrochemical performance as an anode material for lithium-ion batteries than that of another bulk sample with height of 5 μm and adhesive inner structure. When tested at a current density of 500 mA g"−"1, the hierarchical Co_3V_2O_8 hexagonal pyramid exhibited good rate capacity, high cycling stability, and excellent discharge capacity up to 712 mA h g"−"1, making it promising electrode materials for lithium-ion batteries.

  4. Extended automated separation techniques in destructive neutron activation analysis; application to various biological materials, including human tissues and blood

    International Nuclear Information System (INIS)

    Tjioe, P.S.; Goeij, J.J.M. de; Houtman, J.P.W.

    1976-09-01

    Neutron activation analysis may be performed as a multi-element and low-level technique for many important trace elements in biological materials, provided that post-irradiation chemical separations are applied. This paper describes a chemical separation consisting of automated procedures for destruction, distillation, and anion-chromatography. The system developed enables the determination of 14 trace elements in biological materials, viz. antimony, arsenic, bromine, cadmium, chromium, cobalt, copper, gold, iron, mercury, molybdenum, nickel, selenium, and zinc. The aspects of sample preparation, neutron irradiation, gamma-spectrum evaluation, and blank-value contribution are also discussed

  5. Utilisation of biological and secondary raw materials VI. Recycling - conversion to energy; Bio- und Sekundaerrohstoffverwertung VI. Stofflich - energetisch

    Energy Technology Data Exchange (ETDEWEB)

    Wiemer, Klaus; Kern, Michael

    2011-07-01

    In a lot of contributions the Kasseler waste and bio-energy forum reports on a sustainable management of wastes. The organizers hope that this results in a lively dialogue on sustainable activities in waste management corresponding to the responsibility towards future generations. Within the 23rd Kasseler waste and bio-energy forum at 12th to 14th April, 2010 in Kassel (Federal Republic of Germany) lectures were held to the following themes: (1) Perspectives of the waste management; (2) Ressource conservation and securing of raw material; (3) Common capture of packages and high-grade materials; (4) Bin for reusable materials - system trusteeship, material flows, qualities, financing, practical examples; (5) Industrial waste flows, EBS quality assurance and increase of efficiency; (6) New technological developments in the area of fermentation of biological wastes; (7) Perspectives of material and energetical utilization of biological wastes; (8) Renewable Energy Law and direct marketing of 'green' electricity; (9) Technology and experiences with biogas processing; (10) Fermentation of biogenic residues and catering waste; (11) Increase of efficiency of mechanical-biological treatment plants; (12) Mechanical-biological treatment technology in an international environment; (13) Concepts of energetic utilization for landfill sites; (14) Landfill law and landfill after-care; (15) Renaturation of landfills.

  6. Decontamination of chemical and biological warfare agents with a single multi-functional material.

    Science.gov (United States)

    Amitai, Gabi; Murata, Hironobu; Andersen, Jill D; Koepsel, Richard R; Russell, Alan J

    2010-05-01

    We report the synthesis of new polymers based on a dimethylacrylamide-methacrylate (DMAA-MA) co-polymer backbone that support both chemical and biological agent decontamination. Polyurethanes containing the redox enzymes glucose oxidase and horseradish peroxidase can convert halide ions into active halogens and exert striking bactericidal activity against gram positive and gram negative bacteria. New materials combining those biopolymers with a family of N-alkyl 4-pyridinium aldoxime (4-PAM) halide-acrylate co-polymers offer both nucleophilic activity for the detoxification of organophosphorus nerve agents and internal sources of halide ions for generation of biocidal activity. Generation of free bromine and iodine was observed in the combined material resulting in bactericidal activity of the enzymatically formed free halogens that caused complete kill of E. coli (>6 log units reduction) within 1 h at 37 degrees C. Detoxification of diisopropylfluorophosphate (DFP) by the polyDMAA MA-4-PAM iodide component was dose-dependent reaching 85% within 30 min. A subset of 4-PAM-halide co-polymers was designed to serve as a controlled release reservoir for N-hydroxyethyl 4-PAM (HE 4-PAM) molecules that reactivate nerve agent-inhibited acetylcholinesterase (AChE). Release rates for HE 4-PAM were consistent with hydrolysis of the HE 4-PAM from the polymer backbone. The HE 4-PAM that was released from the polymer reactivated DFP-inhibited AChE at a similar rate to the oxime antidote 4-PAM. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  7. Differential laser-induced perturbation spectroscopy and fluorescence imaging for biological and materials sensing

    Science.gov (United States)

    Burton, Dallas Jonathan

    The field of laser-based diagnostics has been a topic of research in various fields, more specifically for applications in environmental studies, military defense technologies, and medicine, among many others. In this dissertation, a novel laser-based optical diagnostic method, differential laser-induced perturbation spectroscopy (DLIPS), has been implemented in a spectroscopy mode and expanded into an imaging mode in combination with fluorescence techniques. The DLIPS method takes advantage of deep ultraviolet (UV) laser perturbation at sub-ablative energy fluences to photochemically cleave bonds and alter fluorescence signal response before and after perturbation. The resulting difference spectrum or differential image adds more information about the target specimen, and can be used in combination with traditional fluorescence techniques for detection of certain materials, characterization of many materials and biological specimen, and diagnosis of various human skin conditions. The differential aspect allows for mitigation of patient or sample variation, and has the potential to develop into a powerful, noninvasive optical sensing tool. The studies in this dissertation encompass efforts to continue the fundamental research on DLIPS including expansion of the method to an imaging mode. Five primary studies have been carried out and presented. These include the use of DLIPS in a spectroscopy mode for analysis of nitrogen-based explosives on various substrates, classification of Caribbean fruit flies versus Caribbean fruit flies that have been irradiated with gamma rays, and diagnosis of human skin cancer lesions. The nitrogen-based explosives and Caribbean fruit flies have been analyzed with the DLIPS scheme using the imaging modality, providing complementary information to the spectroscopic scheme. In each study, a comparison between absolute fluorescence signals and DLIPS responses showed that DLIPS statistically outperformed traditional fluorescence techniques

  8. Use of composite materials for the determination of Cu, As, Mo, Cd and Sb in biological materials by radiochemical neutron activation analysis

    International Nuclear Information System (INIS)

    Lucanikova, M.; John, J.; Kucera, J.; Sebesta, F.

    2006-01-01

    New composite materials were developed and tested for determination of Cu, As, Mo, Cd, and Sb in biological materials by radiochemical neutron activation analysis (RNAA). The materials were prepared by incorporation of solid zinc diethyldithiocarbamate or liquid bis(2,4,4-trimethylpentyl)dithiophosphinic acid (CYANEX 301) into a polyacrylonitrile (PAN) binding matrix. The accuracy of the RNAA procedures was proved by analysis of NIST SRM-1515 Apple Leaves, NIST SRM-1577b Bovine Liver, and NIST SRM-1549 Non Fat Milk Powder. (author)

  9. MAK and BAT values list 2016. Maximum permissible concentrations at the place of work and biological tolerance values for working materials

    International Nuclear Information System (INIS)

    2016-01-01

    The MAK and BAT values list 2016 includes the maximum permissible concentrations at the place of work and biological tolerance values for working materials. The following working materials are covered: carcinogenic working materials, sensitizing materials and aerosols. The report discusses the restriction of exposure peaks, skin resorption, MAK (maximum working place concentration) values during pregnancy, germ cell mutagens and specific working materials. Importance and application of BAT (biological working material tolerance) values, list of materials, carcinogens, biological guide values and reference values are also included.

  10. MAK and BAT values list 2017. Maximum permissible concentrations at the place of work and biological tolerance values for working materials

    International Nuclear Information System (INIS)

    2017-01-01

    The MAK and BAT values list 2017 includes the maximum permissible concentrations at the place of work and biological tolerance values for working materials. The following working materials are covered: carcinogenic working materials, sensitizing materials and aerosols. The report discusses the restriction of exposure peaks, skin resorption, MAK (maximum working place concentration) values during pregnancy, germ cell mutagens and specific working materials. Importance and application of BAT (biological working material tolerance) values, list of materials, carcinogens, biological guide values and reference values are also included.

  11. Accidents with biological material and immunization against hepatitis B among students from the health area.

    Science.gov (United States)

    Gir, Elucir; Netto, Jeniffer Caffer; Malaguti, Silmara Elaine; Canini, Silvia Rita Marin da Silva; Hayashida, Miyeko; Machado, Alcyone Artioli

    2008-01-01

    Undergraduate students from the health area often handle piercing-cutting instruments in their academic activities, which exposes them to the risk of contracting infections. This study aimed to analyze accidents with biological material among these students. Out of 170 accidents registered, 83 (48.8%) occurred with Dentistry students, 69 (40.6%) with Medical students, 11 (6.5%) with Nursing students and in 06 (3.5%) of the cases there was no such information in the files. Most accidents, 106 (62.4%), occurred with students from private schools and 55 (32.3%) with those from public schools. Percutaneous accidents occurred in 133 (78.2%) exposures and there was immediate search for specialized health care in only 38 (21.3%) accidents. In 127 (74.7%) accidents, the immunization schedule against hepatitis B was complete. Therefore, schools need to offer courses and specific class subjects regarding biosafety measures, including aspects related to immunization, especially the vaccine against hepatitis B.

  12. The biological impacts of ingested radioactive materials on the pale grass blue butterfly

    Science.gov (United States)

    Nohara, Chiyo; Hiyama, Atsuki; Taira, Wataru; Tanahara, Akira; Otaki, Joji M.

    2014-05-01

    A massive amount of radioactive materials has been released into the environment by the Fukushima Dai-ichi Nuclear Power Plant accident, but its biological impacts have rarely been examined. Here, we have quantitatively evaluated the relationship between the dose of ingested radioactive cesium and mortality and abnormality rates using the pale grass blue butterfly, Zizeeria maha. When larvae from Okinawa, which is likely the least polluted locality in Japan, were fed leaves collected from polluted localities, mortality and abnormality rates increased sharply at low doses in response to the ingested cesium dose. This dose-response relationship was best fitted by power function models, which indicated that the half lethal and abnormal doses were 1.9 and 0.76 Bq per larva, corresponding to 54,000 and 22,000 Bq per kilogram body weight, respectively. Both the retention of radioactive cesium in a pupa relative to the ingested dose throughout the larval stage and the accumulation of radioactive cesium in a pupa relative to the activity concentration in a diet were highest at the lowest level of cesium ingested. We conclude that the risk of ingesting a polluted diet is realistic, at least for this butterfly, and likely for certain other organisms living in the polluted area.

  13. Sample sizing of biological materials analyzed by energy dispersion X-ray fluorescence

    International Nuclear Information System (INIS)

    Paiva, Jose D.S.; Franca, Elvis J.; Magalhaes, Marcelo R.L.; Almeida, Marcio E.S.; Hazin, Clovis A.

    2013-01-01

    Analytical portions used in chemical analyses are usually less than 1g. Errors resulting from the sampling are barely evaluated, since this type of study is a time-consuming procedure, with high costs for the chemical analysis of large number of samples. The energy dispersion X-ray fluorescence - EDXRF is a non-destructive and fast analytical technique with the possibility of determining several chemical elements. Therefore, the aim of this study was to provide information on the minimum analytical portion for quantification of chemical elements in biological matrices using EDXRF. Three species were sampled in mangroves from the Pernambuco, Brazil. Tree leaves were washed with distilled water, oven-dried at 60 deg C and milled until 0.5 mm particle size. Ten test-portions of approximately 500 mg for each species were transferred to vials sealed with polypropylene film. The quality of the analytical procedure was evaluated from the reference materials IAEA V10 Hay Powder, SRM 2976 Apple Leaves. After energy calibration, all samples were analyzed under vacuum for 100 seconds for each group of chemical elements. The voltage used was 15 kV and 50 kV for chemical elements of atomic number lower than 22 and the others, respectively. For the best analytical conditions, EDXRF was capable of estimating the sample size uncertainty for further determination of chemical elements in leaves. (author)

  14. Sample sizing of biological materials analyzed by energy dispersion X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Paiva, Jose D.S.; Franca, Elvis J.; Magalhaes, Marcelo R.L.; Almeida, Marcio E.S.; Hazin, Clovis A., E-mail: dan-paiva@hotmail.com, E-mail: ejfranca@cnen.gov.br, E-mail: marcelo_rlm@hotmail.com, E-mail: maensoal@yahoo.com.br, E-mail: chazin@cnen.gov.b [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2013-07-01

    Analytical portions used in chemical analyses are usually less than 1g. Errors resulting from the sampling are barely evaluated, since this type of study is a time-consuming procedure, with high costs for the chemical analysis of large number of samples. The energy dispersion X-ray fluorescence - EDXRF is a non-destructive and fast analytical technique with the possibility of determining several chemical elements. Therefore, the aim of this study was to provide information on the minimum analytical portion for quantification of chemical elements in biological matrices using EDXRF. Three species were sampled in mangroves from the Pernambuco, Brazil. Tree leaves were washed with distilled water, oven-dried at 60 deg C and milled until 0.5 mm particle size. Ten test-portions of approximately 500 mg for each species were transferred to vials sealed with polypropylene film. The quality of the analytical procedure was evaluated from the reference materials IAEA V10 Hay Powder, SRM 2976 Apple Leaves. After energy calibration, all samples were analyzed under vacuum for 100 seconds for each group of chemical elements. The voltage used was 15 kV and 50 kV for chemical elements of atomic number lower than 22 and the others, respectively. For the best analytical conditions, EDXRF was capable of estimating the sample size uncertainty for further determination of chemical elements in leaves. (author)

  15. The biological impacts of ingested radioactive materials on the pale grass blue butterfly.

    Science.gov (United States)

    Nohara, Chiyo; Hiyama, Atsuki; Taira, Wataru; Tanahara, Akira; Otaki, Joji M

    2014-05-15

    A massive amount of radioactive materials has been released into the environment by the Fukushima Dai-ichi Nuclear Power Plant accident, but its biological impacts have rarely been examined. Here, we have quantitatively evaluated the relationship between the dose of ingested radioactive cesium and mortality and abnormality rates using the pale grass blue butterfly, Zizeeria maha. When larvae from Okinawa, which is likely the least polluted locality in Japan, were fed leaves collected from polluted localities, mortality and abnormality rates increased sharply at low doses in response to the ingested cesium dose. This dose-response relationship was best fitted by power function models, which indicated that the half lethal and abnormal doses were 1.9 and 0.76 Bq per larva, corresponding to 54,000 and 22,000 Bq per kilogram body weight, respectively. Both the retention of radioactive cesium in a pupa relative to the ingested dose throughout the larval stage and the accumulation of radioactive cesium in a pupa relative to the activity concentration in a diet were highest at the lowest level of cesium ingested. We conclude that the risk of ingesting a polluted diet is realistic, at least for this butterfly, and likely for certain other organisms living in the polluted area.

  16. Determination of 25 elements in biological standard reference materials by neutron activation analysis

    International Nuclear Information System (INIS)

    Guzzi, G.; Pietra, R.; Sabbioni, E.

    1974-12-01

    Standard and Certified Reference Materials programme of the JRC includes the determination of trace elements in complex biological samples delivered by the U.S. National Bureau of Standards: Bovine liver (NBS SRM 1577), Orchard Leaves (NBS SRM 1571) and Tomato Leaves. The study has been performed by the use of neutron activation analysis. Due to the very low concentration of some elements, radiochemical groups or elemental separation procedures were necessary. The paper describes the techniques used to analyse 25 elements. Computer assisted instrumental neutron activation analysis with high resolution Ge(Li) spectrometry was considerably advantageous in the determination of Na, K, Cl, Mn, Fe, Rb and Co and in some cases of Ca, Zn, Cs, Sc, and Cr. For low contents of Ca, Mg, Ni and Si special chemical separation schemes, followed by Cerenkov counting have been developped. Two other separation procedures allowing the determination of As, Cd, Ga, Hg, Mo, Cu, Sr Se, Ba and P have been set up. The first, the simplified one involves the use of high resolution Ge(Li) detectors, the second, the more complete one involves a larger number of shorter measurements performed by simpler and more sensitive techniques, such as NaI(Tl) scintillation spectrometry and Cerenkov counting. The results obtained are presented and discussed

  17. MyLabStocks: a web-application to manage molecular biology materials.

    Science.gov (United States)

    Chuffart, Florent; Yvert, Gaël

    2014-05-01

    Laboratory stocks are the hardware of research. They must be stored and managed with mimimum loss of material and information. Plasmids, oligonucleotides and strains are regularly exchanged between collaborators within and between laboratories. Managing and sharing information about every item is crucial for retrieval of reagents, for planning experiments and for reproducing past experimental results. We have developed a web-based application to manage stocks commonly used in a molecular biology laboratory. Its functionalities include user-defined privileges, visualization of plasmid maps directly from their sequence and the capacity to search items from fields of annotation or directly from a query sequence using BLAST. It is designed to handle records of plasmids, oligonucleotides, yeast strains, antibodies, pipettes and notebooks. Based on PHP/MySQL, it can easily be extended to handle other types of stocks and it can be installed on any server architecture. MyLabStocks is freely available from: https://forge.cbp.ens-lyon.fr/redmine/projects/mylabstocks under an open source licence. © 2014 Laboratoire de Biologie Moleculaire de la Cellule CNRS. Yeast published by John Wiley & Sons, Ltd.

  18. [Accidents with biological materials among nurses in a training hospital: case-control study].

    Science.gov (United States)

    Dalarosa, Micheline Gisele; Lautert, Liana

    2009-03-01

    This case-control study aimed at analyzing the association between occupational stress and disagreement between chronotype and the work shift of nurses who suffered accidents with biological materials in a hospital of Porto Alegre, Rio Grande do Sul, Brazil. A number of 99 workers who suffered accidents (cases) and 232 that had not suffered accidents (controls) were interviewed. Data were collected through the Job Stress Scale according to Karasek's model and the Horne-Ostberg scale The occurrence of accident was not statistically associated with high work requirement scores (p = 0.317), with a chronobiological profile discordant with work shift (p = 0.563), or with other labor variables associated to accidents--overtime, having two jobs (p = 1.000). In addition, there was no significant difference (chi2 Pearson; p = 1.00) among the scores of professionals with high work requirements who work in shifts discordant with their chronotype, both in the case group and in the control group as well.

  19. Determination of rare earth elements in the biological reference materials Pine Needles and Spruce Needles by neutron activation analysis

    International Nuclear Information System (INIS)

    Machado, C.N.; Maria, S.P.; Saiki, M.; Figueiredo, A.M.G.

    1998-01-01

    Instrumental neutron activation analysis was applied to determine La, Ce, Nd, Sm, Eu, Tb, Yb, Lu and Sc in two biological reference materials: NIST 1575 Pine Needles and BCR-CRM 101 Spruce Needles. The purpose was to contribute to the reference data for these two reference materials. The results were obtained with a good precision (relative standard deviations less than 15%). For the Pine Needles reference material there are already some proposed values and our results showed, in general, a good agreement with the data published. The contribution of uranium fission products to La, Ce, Nd and Sm was evaluated and considered in the determination of these elements. Interferences in the determination of rare earth elements in biological materials are also discussed. (author)

  20. Collaborative Research. Fundamental Science of Low Temperature Plasma-Biological Material Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Graves, David Barry [Univ. California, Berkeley, CA (United States); Oehrlein, Gottlieb [Univ. of Maryland, College Park, MD (United States)

    2014-09-01

    atmospheric pressure using several types of low temperature plasma sources, for which radical induced interactions generally dominate due to short mean free paths of ions and VUV photons. For these conditions we demonstrated the importance of environmental interactions when atmospheric pressure plasma sources are used to modify biomolecules. This is evident from both gas phase characterization data and in-situ surface characterization of treated biomolecules. Environmental interactions can produce unexpected outcomes due to the complexity of reactions of reactive species with the atmosphere which determines the composition of reactive fluxes and atomistic changes of biomolecules. Overall, this work clarified a richer spectrum of scientific opportunities and challenges for the field of low temperature plasma-biomolecule surface interactions than initially anticipated, in particular for plasma sources operating at atmospheric pressure. The insights produced in this work, e.g. demonstration of the importance of environmental interactions, are generally important for applications of APP to materials modifications. Thus one major contributions of this research has been the establishment of methodologies to more systematically study the interaction of plasma with bio-molecules. In particular, our studies of atmospheric pressure plasma sources using very well-defined experimental conditions enabled to combine atomistic surface modifications of biomolecules with changes in their biological function. The clarification of the role of ions, VUV photons and radicals in deactivation of biomolecules during low pressure and atmospheric pressure plasma-biomolecule interaction has broad implications, e.g. for the emerging field of plasma medicine. The development of methods to detect the effects of plasma treatment on immune-active biomolecules will be helpful in many future studies.

  1. Electrothermally Tunable Bridge Resonator

    KAUST Repository

    Hajjaj, Amal Z.; Alcheikh, Nouha; Ramini, Abdallah; Hafiz, Md Abdullah Al; Younis, Mohammad I.

    2016-01-01

    This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of an in-plane clamped-clamped microbeam, bridge, and resonator compressed by a force due to electrothermal actuation. We demonstrate that a single resonator can be operated at a wide range of frequencies. The microbeam is actuated electrothermally, by passing a DC current through it. We show that when increasing the electrothermal voltage, the compressive stress inside the microbeam increases, which leads eventually to its buckling. Before buckling, the fundamental frequency decreases until it drops to very low values, almost to zero. After buckling, the fundamental frequency increases, which is shown to be as high as twice the original resonance frequency. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and to simulation results of a multi-physics finite-element model. A good agreement is found among all the results.

  2. Electrothermally Tunable Bridge Resonator

    KAUST Repository

    Hajjaj, Amal Z.

    2016-12-05

    This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of an in-plane clamped-clamped microbeam, bridge, and resonator compressed by a force due to electrothermal actuation. We demonstrate that a single resonator can be operated at a wide range of frequencies. The microbeam is actuated electrothermally, by passing a DC current through it. We show that when increasing the electrothermal voltage, the compressive stress inside the microbeam increases, which leads eventually to its buckling. Before buckling, the fundamental frequency decreases until it drops to very low values, almost to zero. After buckling, the fundamental frequency increases, which is shown to be as high as twice the original resonance frequency. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and to simulation results of a multi-physics finite-element model. A good agreement is found among all the results.

  3. Novel synthesis of covalently linked silicon quantum dot–polystyrene hybrid materials: Silicon quantum dot–polystyrene polymers of tunable refractive index

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jin-Kyu; Dung, Mai Xuan; Jeong, Hyun-Dam, E-mail: hdjeong@chonnam.ac.kr

    2014-11-14

    We present a new material design concept, silicon quantum dot (Si QD) polymers, for which surface-functionalized Si QDs can be regarded as a large monomer in the polymers. As a prototypical example, vinyl-functionalized Si QDs, i.e., divinylbenzene-capped Si QDs (DVB-Si QDs) synthesized by adopting divinylbenzene (DVB) capping molecule to the hydride-terminated Si QD (H-Si QD) via Pt-catalyzed hydrosilylation was introduced and polymerized with a styrene monomer to yield Si QD–polystyrene (Si QD–PS) polymers. To demonstrate controllability of the content of Si QDs in the polymers as in conventional polymers, three Si QD content varied Si QD–PS polymers were systematically prepared, named as Si QD–PS-A, Si QD–PS-B, and Si QD–PS-C. It has been demonstrated that the content of the Si QDs in the Si QD–PS polymers was well controlled by the amount of the DVB-Si QD used, as found to be 3.8 wt% (Si QD–PS-A), 10.0 wt% (Si QD–PS-B), 20.0 wt% (Si QD–PS-A), and 37.4 wt% (DVB-Si QD), which was deduced from TGA results. Thin films of the Si QD–PS polymers and the freestanding DVB-Si QDs were successfully fabricated by a spin-coating method and it was found that the refractive index of the thin films dried at 40 °C was linearly increased as the content of the Si QD in the polymers was increased from 1.586 (0 wt%), to 1.590 (3.8 wt%), to 1.592 (10.0 wt%), to 1.592 (20.0 wt%), and to 1.614 (37.4 wt%). - Highlights: • A new material design concept, Si QD polymer, is presented. • Freestanding vinyl-functionalized Si QD was synthesized as a monomer for polymer. • Si QD–PS polymers were synthesized by polymerization of styrene with vinyl-Si QD. • Concentration of Si QD in the polymer was well controlled by amount of Si QD used. • Refractive index of polymer thin films linearly increased with concentration of Si QD.

  4. Novel synthesis of covalently linked silicon quantum dot–polystyrene hybrid materials: Silicon quantum dot–polystyrene polymers of tunable refractive index

    International Nuclear Information System (INIS)

    Choi, Jin-Kyu; Dung, Mai Xuan; Jeong, Hyun-Dam

    2014-01-01

    We present a new material design concept, silicon quantum dot (Si QD) polymers, for which surface-functionalized Si QDs can be regarded as a large monomer in the polymers. As a prototypical example, vinyl-functionalized Si QDs, i.e., divinylbenzene-capped Si QDs (DVB-Si QDs) synthesized by adopting divinylbenzene (DVB) capping molecule to the hydride-terminated Si QD (H-Si QD) via Pt-catalyzed hydrosilylation was introduced and polymerized with a styrene monomer to yield Si QD–polystyrene (Si QD–PS) polymers. To demonstrate controllability of the content of Si QDs in the polymers as in conventional polymers, three Si QD content varied Si QD–PS polymers were systematically prepared, named as Si QD–PS-A, Si QD–PS-B, and Si QD–PS-C. It has been demonstrated that the content of the Si QDs in the Si QD–PS polymers was well controlled by the amount of the DVB-Si QD used, as found to be 3.8 wt% (Si QD–PS-A), 10.0 wt% (Si QD–PS-B), 20.0 wt% (Si QD–PS-A), and 37.4 wt% (DVB-Si QD), which was deduced from TGA results. Thin films of the Si QD–PS polymers and the freestanding DVB-Si QDs were successfully fabricated by a spin-coating method and it was found that the refractive index of the thin films dried at 40 °C was linearly increased as the content of the Si QD in the polymers was increased from 1.586 (0 wt%), to 1.590 (3.8 wt%), to 1.592 (10.0 wt%), to 1.592 (20.0 wt%), and to 1.614 (37.4 wt%). - Highlights: • A new material design concept, Si QD polymer, is presented. • Freestanding vinyl-functionalized Si QD was synthesized as a monomer for polymer. • Si QD–PS polymers were synthesized by polymerization of styrene with vinyl-Si QD. • Concentration of Si QD in the polymer was well controlled by amount of Si QD used. • Refractive index of polymer thin films linearly increased with concentration of Si QD

  5. Multi trace element analysis of dry biological materials by neutron activation analysis including a chemical group separation

    International Nuclear Information System (INIS)

    Weers, C.A.

    1980-07-01

    Multi-element analysis of dry biological material by neutron activation analysis has to include radiochemical separation. The evaporation process is described in terms of the half-volume. The pretreatment of the samples and the development of the destruction-evaporation apparatus are described. The successive adsorption steps with active charcoal, Al 2 O 3 and coprecipitation with Fe(OH) 3 are described. Results obtained for standard reference materials are summarized. (G.T.H.)

  6. Tunable thin-film optical filters for hyperspectral microscopy

    Science.gov (United States)

    Favreau, Peter F.; Rich, Thomas C.; Prabhat, Prashant; Leavesley, Silas J.

    2013-02-01

    Hyperspectral imaging was originally developed for use in remote sensing applications. More recently, it has been applied to biological imaging systems, such as fluorescence microscopes. The ability to distinguish molecules based on spectral differences has been especially advantageous for identifying fluorophores in highly autofluorescent tissues. A key component of hyperspectral imaging systems is wavelength filtering. Each filtering technology used for hyperspectral imaging has corresponding advantages and disadvantages. Recently, a new optical filtering technology has been developed that uses multi-layered thin-film optical filters that can be rotated, with respect to incident light, to control the center wavelength of the pass-band. Compared to the majority of tunable filter technologies, these filters have superior optical performance including greater than 90% transmission, steep spectral edges and high out-of-band blocking. Hence, tunable thin-film optical filters present optical characteristics that may make them well-suited for many biological spectral imaging applications. An array of tunable thin-film filters was implemented on an inverted fluorescence microscope (TE 2000, Nikon Instruments) to cover the full visible wavelength range. Images of a previously published model, GFP-expressing endothelial cells in the lung, were acquired using a charge-coupled device camera (Rolera EM-C2, Q-Imaging). This model sample presents fluorescently-labeled cells in a highly autofluorescent environment. Linear unmixing of hyperspectral images indicates that thin-film tunable filters provide equivalent spectral discrimination to our previous acousto-optic tunable filter-based approach, with increased signal-to-noise characteristics. Hence, tunable multi-layered thin film optical filters may provide greatly improved spectral filtering characteristics and therefore enable wider acceptance of hyperspectral widefield microscopy.

  7. Efficiency of biological activator formulated material (BAFM) for volatile organic compounds removal--preliminary batch culture tests with activated sludge.

    Science.gov (United States)

    Corre, Charline; Couriol, Catherine; Amrane, Abdeltif; Dumont, Eric; Andrès, Yves; Le Cloirec, Pierre

    2012-01-01

    During biological degradation, such as biofiltration of air loaded with volatile organic compounds, the pollutant is passed through a bed packed with a solid medium acting as a biofilm support. To improve microorganism nutritional equilibrium and hence to enhance the purification capacities, a Biological Activator Formulated Material (BAFM) was developed, which is a mixture of solid nutrients dissolving slowly in a liquid phase. This solid was previously validated on mineral pollutants: ammonia and hydrogen sulphide. To evaluate the efficiency of such a material for biodegradation of some organic compounds, a simple experiment using an activated sludge batch reactor was carried out. The pollutants (sodium benzoate, phenol, p-nitrophenol and 2-4-dichlorophenol) were in the concentration range 100 to 1200 mg L(-1). The positive impact of the formulated material was shown. The improvement of the degradation rates was in the range 10-30%. This was the consequence of the low dissolution of the nutrients incorporated during material formulation, followed by their consumption by the biomass, as shown for urea used as a nitrogen source. Owing to its twofold interest (mechanical resistance and nutritional supplementation), the Biological Activator Formulated Material seems to be a promising material. Its addition to organic or inorganic supports should be investigated to confirm its relevance for implementation in biofilters.

  8. The development of peptide-based interfacial biomaterials for generating biological functionality on the surface of bioinert materials.

    Science.gov (United States)

    Meyers, Steven R; Khoo, Xiaojuan; Huang, Xin; Walsh, Elisabeth B; Grinstaff, Mark W; Kenan, Daniel J

    2009-01-01

    Biomaterials used in implants have traditionally been selected based on their mechanical properties, chemical stability, and biocompatibility. However, the durability and clinical efficacy of implantable biomedical devices remain limited in part due to the absence of appropriate biological interactions at the implant interface and the lack of integration into adjacent tissues. Herein, we describe a robust peptide-based coating technology capable of modifying the surface of existing biomaterials and medical devices through the non-covalent binding of modular biofunctional peptides. These peptides contain at least one material binding sequence and at least one biologically active sequence and thus are termed, "Interfacial Biomaterials" (IFBMs). IFBMs can simultaneously bind the biomaterial surface while endowing it with desired biological functionalities at the interface between the material and biological realms. We demonstrate the capabilities of model IFBMs to convert native polystyrene, a bioinert surface, into a bioactive surface that can support a range of cell activities. We further distinguish between simple cell attachment with insufficient integrin interactions, which in some cases can adversely impact downstream biology, versus biologically appropriate adhesion, cell spreading, and cell survival mediated by IFBMs. Moreover, we show that we can use the coating technology to create spatially resolved patterns of fluorophores and cells on substrates and that these patterns retain their borders in culture.

  9. Tunable Mechanical Metamaterials through Hybrid Kirigami Structures.

    Science.gov (United States)

    Hwang, Doh-Gyu; Bartlett, Michael D

    2018-02-21

    Inspired by the art of paper cutting, kirigami provides intriguing tools to create materials with unconventional mechanical and morphological responses. This behavior is appealing in multiple applications such as stretchable electronics and soft robotics and presents a tractable platform to study structure-property relationships in material systems. However, mechanical response is typically controlled through a single or fractal cut type patterned across an entire kirigami sheet, limiting deformation modes and tunability. Here we show how hybrid patterns of major and minor cuts creates new opportunities to introduce boundary conditions and non-prismatic beams to enable highly tunable mechanical responses. This hybrid approach reduces stiffness by a factor of ~30 while increasing ultimate strain by a factor of 2 (up to 750% strain) relative to single incision patterns. We present analytical models and generate general design criteria that is in excellent agreement with experimental data from nanoscopic to macroscopic systems. These hybrid kirigami materials create new opportunities for multifunctional materials and structures, which we demonstrate with stretchable kirigami conductors with nearly constant electrical resistance up to >400% strain and magnetoactive actuators with extremely rapid response (>10,000% strain s -1 ) and high, repeatable elongation (>300% strain).

  10. Tunable plasmonic toroidal terahertz metamodulator

    Science.gov (United States)

    Gerislioglu, Burak; Ahmadivand, Arash; Pala, Nezih

    2018-04-01

    Optical modulators are essential and strategic parts of micro- and nanophotonic circuits to encode electro-optical signals in the optical domain. Here, by using arrays of multipixel toroidal plasmonic terahertz (THz) metamolecules, we developed a functional plasmonic metamodulator with high efficiency and tunability. Technically, the dynamic toroidal dipole induces nonradiating charge-current arrangements leading to have an exquisite role in defining the inherent spectral features of various materials. By categorizing in a different family of multipoles far from the traditional electromagnetic multipoles, the toroidal dipole corresponds to poloidal currents flowing on the surface of a closed-loop torus. Utilizing the sensitivity of the optically driven toroidal momentum to the incident THz beam power and by employing both numerical tools and experimental analysis, we systematically studied the spectral response of the proposed THz plasmonic metadevice. In this Rapid Communication, we uncover a correlation between the existence and the excitation of the toroidal response and the incident beam power. This mechanism is employed to develop THz toroidal metamodulators with a strong potential to be employed for practical advanced and next-generation communication, filtering, and routing applications.

  11. Electrostatically Tunable Nanomechanical Shallow Arches

    KAUST Repository

    Kazmi, Syed N. R.

    2017-11-03

    We report an analytical and experimental study on the tunability of in-plane doubly-clamped nanomechanical arches under varied DC bias conditions at room temperature. For this purpose, silicon based shallow arches are fabricated using standard e-beam lithography and surface nanomachining of a highly conductive device layer on a silicon-on-insulator (SOI) wafer. The experimental results show good agreement with the analytical results with a maximum tunability of 108.14% for 180 nm thick arch with a transduction gap of 1 μm between the beam and the driving/sensing electrodes. The high tunability of shallow arches paves the ways for highly tunable band pass filtering applications in high frequency range.

  12. Improved algorithm for estimating optical properties of food and biological materials using spatially-resolved diffuse reflectance

    Science.gov (United States)

    In this research, the inverse algorithm for estimating optical properties of food and biological materials from spatially-resolved diffuse reflectance was optimized in terms of data smoothing, normalization and spatial region of reflectance profile for curve fitting. Monte Carlo simulation was used ...

  13. Investigation of biological material for metallic poisoning by the fractional method. Issledovaniya biologicheskogo materiala na metallicheskiya yady drobnym metodom

    Energy Technology Data Exchange (ETDEWEB)

    Krylova, A.N.

    1975-01-01

    A fractional method is developed for analysis of biological material for the presence of toxic quantities of Pb, Hg, Ba, Mn, Cr, Ag, Cu, Sb, Tl, As, Bi, Cd and Zn. The method satisfies the requirements of medical forensic toxicology. (Ref. Zh.)

  14. Tunable on chip optofluidic laser

    DEFF Research Database (Denmark)

    Bakal, Avraham; Vannahme, Christoph; Kristensen, Anders

    2016-01-01

    On chip tunable laser is demonstrated by realizing a microfluidic droplet array. The periodicity is controlled by the pressure applied to two separate inlets, allowing to tune the lasing frequency over a broad spectral range.......On chip tunable laser is demonstrated by realizing a microfluidic droplet array. The periodicity is controlled by the pressure applied to two separate inlets, allowing to tune the lasing frequency over a broad spectral range....

  15. Tunable femtosecond Cherenkov fiber laser

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Svane, Ask Sebastian; Lægsgaard, Jesper

    2014-01-01

    We demonstrate electrically-tunable femtosecond Cherenkov fiber laser output at the visible range. Using an all-fiber, self-starting femtosecond Yb-doped fiber laser as the pump source and nonlinear photonic crystal fiber link as the wave-conversion medium, ultrafast, milliwatt-level, tunable...... and spectral isolated Cherenkov radiation at visible wavelengths are reported. Such a femtosecond Cherenkov laser source is promising for practical biophotonics applications....

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

    International Nuclear Information System (INIS)

    Muramatsu, Y.; Parr, R.M.

    1985-12-01

    This report focuses on analytical reference materials which have been developed for use in connection with the determination of toxic and essential trace elements in biomedical and health-related environmental samples. Data are reported on 60 biological and 40 environmental (non-biological) reference materials from 11 suppliers. Certified concentration values (or their equivalents) and non-certified concentration values (or information values) are presented in various tables which are intended to help the user select a reference material that matches as closely as possible (i.e. with respect to matrix type and concentration of the element of interest) the ''real'' samples that are to be analysed. These tables have been generated from a database characterized by the following parameters: total number of reference materials=100; total number of elements recorded=69; total number of concentration values recorded=1771. Also included in the report is information (where available) on the cost of each material, the unit weight or volume supplied, and the minimum weight of material recommended for analysis. (author)

  17. Tunable optical absorption in silicene molecules

    KAUST Repository

    Mokkath, Junais Habeeb; Schwingenschlö gl, Udo

    2016-01-01

    Two-dimensional materials with a tunable band gap that covers a wide range of the solar spectrum hold great promise for sunlight harvesting. For this reason, we investigate the structural, electronic, and optical properties of silicene molecules using time dependent density functional theory. We address the influence of the molecular size, buckling, and charge state as well as that of a dielectric environment. Unlike planar graphene molecules, silicene molecules prefer to form low-buckled structures with strong visible to ultraviolet optical response. We also identify molecular plasmons.

  18. Tunable optical absorption in silicene molecules

    KAUST Repository

    Mokkath, Junais Habeeb

    2016-07-13

    Two-dimensional materials with a tunable band gap that covers a wide range of the solar spectrum hold great promise for sunlight harvesting. For this reason, we investigate the structural, electronic, and optical properties of silicene molecules using time dependent density functional theory. We address the influence of the molecular size, buckling, and charge state as well as that of a dielectric environment. Unlike planar graphene molecules, silicene molecules prefer to form low-buckled structures with strong visible to ultraviolet optical response. We also identify molecular plasmons.

  19. A novel optogenetically tunable frequency modulating oscillator.

    Directory of Open Access Journals (Sweden)

    Tarun Mahajan

    Full Text Available Synthetic biology has enabled the creation of biological reconfigurable circuits, which perform multiple functions monopolizing a single biological machine; Such a system can switch between different behaviours in response to environmental cues. Previous work has demonstrated switchable dynamical behaviour employing reconfigurable logic gate genetic networks. Here we describe a computational framework for reconfigurable circuits in E.coli using combinations of logic gates, and also propose the biological implementation. The proposed system is an oscillator that can exhibit tunability of frequency and amplitude of oscillations. Further, the frequency of operation can be changed optogenetically. Insilico analysis revealed that two-component light systems, in response to light within a frequency range, can be used for modulating the frequency of the oscillator or stopping the oscillations altogether. Computational modelling reveals that mixing two colonies of E.coli oscillating at different frequencies generates spatial beat patterns. Further, we show that these oscillations more robustly respond to input perturbations compared to the base oscillator, to which the proposed oscillator is a modification. Compared to the base oscillator, the proposed system shows faster synchronization in a colony of cells for a larger region of the parameter space. Additionally, the proposed oscillator also exhibits lesser synchronization error in the transient period after input perturbations. This provides a strong basis for the construction of synthetic reconfigurable circuits in bacteria and other organisms, which can be scaled up to perform functions in the field of time dependent drug delivery with tunable dosages, and sets the stage for further development of circuits with synchronized population level behaviour.

  20. Detection of small number of Giardia in biological materials prepared from stray dogs.

    Science.gov (United States)

    Esmailikia, Leila; Ebrahimzade, Elahe; Shayan, Parviz; Amininia, Narges

    2017-12-20

    Giardia lamblia is an intestinal protozoa with intermittent and low shedding especially in dogs, and the detection of Giardia is accompanied with problems such as sampling and diagnostic method. The objective of this study was to detection of Giardia in biological materials with low number of parasite using parasitological and molecular methods, and also to determine whether the examined stray dogs harbor known zoonotic genotype of Giardia. For this aim 85 fecal and duodenal samples were studied from which 1 was positive by Trichrome staining of stool, 4 were positive by staining of duodenal samples. The nested PCR analysis with primers derived from 18 SrRNA showed that the specific PCR product could be amplified in 4 stool and 4 duodenal samples. All positive samples in staining analysis were also positive in nested PCR. No amplification could be observed by nested PCR with primers derived from β giardin gene due to the single copy of gene. Interestingly, the extracted DNA from old fixed stained Giardia positive smears could be also amplified with primers derived from 18SrRNA gene. The sequence analysis of nested PCR products showed that they belong to the genotype D. In conclusion, it is to denote that the Trichrome or Giemsa methods were not suitable for the detection of small number of this parasite in stool and the nested PCR with primers derived from 18S rRNA gene can replace the traditional methods successfully. For detection of Giardia in stool, primers derived from β giardin will not be recommended.

  1. Updated Lagrangian finite element formulations of various biological soft tissue non-linear material models: a comprehensive procedure and review.

    Science.gov (United States)

    Townsend, Molly T; Sarigul-Klijn, Nesrin

    2016-01-01

    Simplified material models are commonly used in computational simulation of biological soft tissue as an approximation of the complicated material response and to minimize computational resources. However, the simulation of complex loadings, such as long-duration tissue swelling, necessitates complex models that are not easy to formulate. This paper strives to offer the updated Lagrangian formulation comprehensive procedure of various non-linear material models for the application of finite element analysis of biological soft tissues including a definition of the Cauchy stress and the spatial tangential stiffness. The relationships between water content, osmotic pressure, ionic concentration and the pore pressure stress of the tissue are discussed with the merits of these models and their applications.

  2. Quantification of ultraviolet photon emission from interaction of charged particles in materials of interest in radiation biology research

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Syed Bilal, E-mail: ahmadsb@mcmaster.ca [Department of Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, ON (Canada); Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences, Islamabad (Pakistan); McNeill, Fiona E., E-mail: fmcneill@mcmaster.ca [Department of Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, ON (Canada); Prestwich, William V., E-mail: prestwic@mcmaster.ca [Department of Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, ON (Canada); Byun, Soo Hyun, E-mail: soohyun@mcmaster.ca [Department of Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, ON (Canada); Seymour, Colin, E-mail: seymouc@mcmaster.ca [Department of Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, ON (Canada); Mothersill, Carmel E., E-mail: mothers@mcmaster.ca [Department of Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, ON (Canada)

    2014-01-15

    In radiation biology experiments often cells are irradiated using charged particles with the intention that only a specified number of cells are hit by the primary ion track. However, in doing so several other materials such as the cell container and the growth media etc. are also irradiated, and UV radiation emitted from these materials can potentially interact with the cells. We have hypothesized that some “bystander effects” that are thought to be chemically mediated, may be, in fact, a physical effect, where UV is interacting with non-targeted cells. Based upon our hypothesis we quantified the emission of UV from Polypropylene, Mylar, Teflon, and Cellophane which are all commonly used materials in radiation biology experiments. Additionally we measured the NIST standard materials of Oyster tissue and Citrus leaves as these powdered materials are derived from living cells. Protons accelerated up to an energy of 2.2 MeV, in a 3 MV Van de Graff accelerator, were used for irradiation. Beam current was kept to 10 nA, which corresponds to a proton fluence rate of 2.7 × 10{sup 10} protons mm{sup −2} s{sup −1}. All the materials were found to emit light at UV frequencies and intensities that were significant enough to conduct a further investigation for their biological consequences. Mylar and polypropylene are commonly used in radiation induced bystander effect studies and are considered to be non-fluorescent. However our study showed that this is not the case. Significant luminescence observed from the irradiated NIST standard reference materials for Oyster tissue and Citrus leaves verified that the luminescence emission is not restricted only to the polymeric materials that are used to contain cells. It can also occur from ion interactions within the cells as well.

  3. Chemically-functionalized microcantilevers for detection of chemical, biological and explosive material

    Science.gov (United States)

    Pinnaduwage, Lal A [Knoxville, TN; Thundat, Thomas G [Knoxville, TN; Brown, Gilbert M [Knoxville, TN; Hawk, John Eric [Olive Branch, MS; Boiadjiev, Vassil I [Knoxville, TN

    2007-04-24

    A chemically functionalized cantilever system has a cantilever coated on one side thereof with a reagent or biological species which binds to an analyte. The system is of particular value when the analyte is a toxic chemical biological warfare agent or an explosive.

  4. Radioprotection, biological effects of the radiations and security in the handling of radioactive material

    CERN Document Server

    Teran, M

    2000-01-01

    The development of the philosophy of the radioprotection is dependent on the understanding of the effects of the radiation in the man. Behind the fact that the radiation is able to produce biological damages there are certain factors with regard to the biological effects of the radiations that determine the boarding of the radioprotection topics.

  5. Digital learning material for experimental design and model building in molecular biology

    NARCIS (Netherlands)

    Aegerter-Wilmsen, T.

    2005-01-01

    Designing experimental approaches is a major cognitive skill in molecular biology research, and building models, including quantitative ones, is a cognitive skill which is rapidly gaining importance. Since molecular biology education at university level is aimed at educating future researchers, we

  6. EDITORIAL: Nanotechnology at the interface of cell biology, materials science and medicine Nanotechnology at the interface of cell biology, materials science and medicine

    Science.gov (United States)

    Engel, Andreas; Miles, Mervyn

    2008-09-01

    The atomic force microscope (AFM) and related scanning probe microscopes have become resourceful tools to study cells, supramolecular assemblies and single biomolecules, because they allow investigations of such structures in native environments. Quantitative information has been gathered about the surface structure of membrane proteins to lateral and vertical resolutions of 0.5 nm and 0.1 nm, respectively, about the forces that keep protein-protein and protein-nucleic acid assemblies together as well as single proteins in their native conformation, and about the nanomechanical properties of cells in health and disease. Such progress has been achieved mainly because of constant development of AFM instrumentation and sample preparation methods. This special issue of Nanotechnology presents papers from leading laboratories in the field of nanobiology, covering a wide range of topics in the form of original and novel scientific contributions. It addresses achievements in instrumentation, sample preparation, automation and in biological applications. These papers document the creativity and persistence of researchers pursuing the goal to unravel the structure and dynamics of cells, supramolecuar structures and single biomolecules at work. Improved cantilever sensors, novel optical probes, and quantitative data on supports for electrochemical experiments open new avenues for characterizing biological nanomachines down to the single molecule. Comparative measurements of healthy and metastatic cells promise new methods for early detection of tumors, and possible assessments of drug efficacy. High-speed AFMs document possibilities to monitor crystal growth and to observe large structures at video rate. A wealth of information on amyloid-type fibers as well as on membrane proteins has been gathered by single molecule force spectroscopy—a technology now being automated for large-scale data collection. With the progress of basic research and a strong industry supporting

  7. Enhanced surface functionality via plasma modification and plasma deposition techniques to create more biologically relevant materials

    Science.gov (United States)

    Shearer, Jeffrey C.

    Functionalizing nanoparticles and other unusually shaped substrates to create more biologically relevant materials has become central to a wide range of research programs. One of the primary challenges in this field is creating highly functionalized surfaces without modifying the underlying bulk material. Traditional wet chemistry techniques utilize thin film depositions to functionalize nanomaterials with oxygen and nitrogen containing functional groups, such as --OH and --NHx. These functional groups can serve to create surfaces that are amenable to cell adhesion or can act as reactive groups for further attachment of larger structures, such as macromolecules or antiviral agents. Additional layers, such as SiO2, are often added between the nanomaterial and the functionalized coating to act as a barrier films, adhesion layers, and to increase overall hydrophilicity. However, some wet chemistry techniques can damage the bulk material during processing. This dissertation examines the use of plasma processing as an alternative method for producing these highly functionalized surfaces on nanoparticles and polymeric scaffolds through the use of plasma modification and plasma enhanced chemical vapor deposition techniques. Specifically, this dissertation will focus on (1) plasma deposition of SiO2 barrier films on nanoparticle substrates; (2) surface functionalization of amine and alcohol groups through (a) plasma co-polymerization and (b) plasma modification; and (3) the design and construction of plasma hardware to facilitate plasma processing of nanoparticles and polymeric scaffolds. The body of work presented herein first examines the fabrication of composite nanoparticles by plasma processing. SiOxC y and hexylamine films were coated onto TiO2 nanoparticles to demonstrate enhanced water dispersion properties. Continuous wave and pulsed allyl alcohol plasmas were used to produce highly functionalized Fe2 O3 supported nanoparticles. Specifically, film composition was

  8. "Solvent-in-salt" systems for design of new materials in chemistry, biology and energy research.

    Science.gov (United States)

    Azov, Vladimir A; Egorova, Ksenia S; Seitkalieva, Marina M; Kashin, Alexey S; Ananikov, Valentine P

    2018-02-21

    Inorganic and organic "solvent-in-salt" (SIS) systems have been known for decades but have attracted significant attention only recently. Molten salt hydrates/solvates have been successfully employed as non-flammable, benign electrolytes in rechargeable lithium-ion batteries leading to a revolution in battery development and design. SIS with organic components (for example, ionic liquids containing small amounts of water) demonstrate remarkable thermal stability and tunability, and present a class of admittedly safer electrolytes, in comparison with traditional organic solvents. Water molecules tend to form nano- and microstructures (droplets and channel networks) in ionic media impacting their heterogeneity. Such microscale domains can be employed as microreactors for chemical and enzymatic synthesis. In this review, we address known SIS systems and discuss their composition, structure, properties and dynamics. Special attention is paid to the current and potential applications of inorganic and organic SIS systems in energy research, chemistry and biochemistry. A separate section of this review is dedicated to experimental methods of SIS investigation, which is crucial for the development of this field.

  9. How to Choose between the Implant Materials Steel and Titanium in Orthopedic Trauma Surgery: Part 2 - Biological Aspects.

    Science.gov (United States)

    Perren, S M; Regazzoni, P; Fernandez, A A

    2017-01-01

    BIOLOGICAL ASPECTS OF STEEL AND TITANIUM AS IMPLANT MATERIAL IN ORTHOPEDIC TRAUMA SURGERY The following case from the ICUC database, where a titanium plate was implanted into a flourishing infection, represents the clinical experience leading to preferring titanium over steel. (Fig. 1) (6). Current opinions regarding biological aspects of implant function. The "street" opinions regarding the biological aspects of the use of steel versus titanium as a surgical trauma implant material differ widely. Statements of opinion leaders range from "I do not see any difference in the biological behavior between steel and titanium in clinical application" to "I successfully use titanium implants in infected areas in a situation where steel would act as foreign body "sustaining" infection." Furthermore, some comments imply that clinical proof for the superiority of titanium in human application is lacking. The following tries to clarify the issues addressing the different aspects more through a practical clinical approach than a purely scientific one, this includes simplifications. Today's overall biocompatibility of implant materials is acceptable but: As the vast majority of secondary surgeries are elective procedures this allows the selection of implant materials with optimal infection resistance. The different biological reactions of stainless steel and titanium are important for this segment of clinical pathologies. Biological tole - rance (18) depends on the toxicity and on the amount of soluble implant material released. Release, diffusion and washout through blood circulation determine the local concentration of the corrosion products. Alloying components of steel, especially nickel and chromium, are less than optimal in respect to tissue tolerance and allergenicity. Titanium as a pure metal provides excellent biological tolerance (3, 4, 16). Better strength was obtained by titanium alloys like TiAl6V4. The latter found limited application as surgical implants. It

  10. A common basis for facilitated legitimate exchange of biological materials proposed by the European Culture Collections' Organisation

    Directory of Open Access Journals (Sweden)

    Dagmar Fritze

    2009-12-01

    Full Text Available Being charged with the task of accessioning and supplying of living microbiological material, microbial culture collections are institutions that play a central role between the interests of a variety of user communities. On the one side are the providers of living microbiological material, such as individual scientists, institutions and countries of origin and on the other side are the various kinds of recipients/users of cultures of microorganisms from academia and industry. Thus, providing access to high quality biological material and scientific services while at the same time observing donor countries' rights, intellectual property rights, biosafety and biosecurity aspects poses demanding challenges. E.g. donor countries rights relate to Article 15 of the Convention on Biological Diversity: "Contracting parties …. recognize the sovereign rights of states over their natural resources …. shall facilitate access to resources … and not impose restrictions that run counter to the aims of the Convention. Access to natural resources shall be by mutually agreed terms and subject to prior informed consent ..." The use of a proposed standard contract by culture collections is discussed as a way of contractually safeguarding the existing research commons, while observing the new rights established in the Convention on Biological Diversity as well as other existing and new legislation impacting on the accessibility of living microbial material.

  11. Tunable Multiband Microwave Photonic Filters

    Directory of Open Access Journals (Sweden)

    Mable P. Fok

    2017-11-01

    Full Text Available The increasing demand for multifunctional devices, the use of cognitive wireless technology to solve the frequency resource shortage problem, as well as the capabilities and operational flexibility necessary to meet ever-changing environment result in an urgent need of multiband wireless communications. Spectral filter is an essential part of any communication systems, and in the case of multiband wireless communications, tunable multiband RF filters are required for channel selection, noise/interference removal, and RF signal processing. Unfortunately, it is difficult for RF electronics to achieve both tunable and multiband spectral filtering. Recent advancements of microwave photonics have proven itself to be a promising candidate to solve various challenges in RF electronics including spectral filtering, however, the development of multiband microwave photonic filtering still faces lots of difficulties, due to the limited scalability and tunability of existing microwave photonic schemes. In this review paper, we first discuss the challenges that were facing by multiband microwave photonic filter, then we review recent techniques that have been developed to tackle the challenge and lead to promising developments of tunable microwave photonic multiband filters. The successful design and implementation of tunable microwave photonic multiband filter facilitate the vision of dynamic multiband wireless communications and radio frequency signal processing for commercial, defense, and civilian applications.

  12. PENGEMBANGAN HANDOUT BERBASIS KONTEKSTUAL PADA PELAJARAN BIOLOGI MATERI BIOTEKNOLOGI UNTUK SISWA KELAS XII SMK NEGERI 02 BATU

    Directory of Open Access Journals (Sweden)

    Fega Rahmayani

    2015-03-01

    Full Text Available The teaching learning activity in SMK is inappropriate with the purpose of teaching and learning in SMK, which the students are taught to be able to apply the materials in the real life. Teaching material is taken from the biology book of SMA that the content is theoretically, so the explanation on the material is unsuitable and not applicative that makes the student less in ability and skill for application in daily life. From the problem above, this research purpose on developing the contextual basic handout of the biological course in biotechnology material in SMK N 02 Batu.This research is developing research based on research and development by Sugiyono’s model that use a few developing steps, those are: (1 Potential and problem, (2 Collecting data, (3 Product design, (4 Validation design, (5 Design revision, (6 Try out the product, (7 Product revision. The data collecting methods is using validation from the expert of handout, material expert and try out to the study club. The technique of analyze data using quantitative and qualitative data. The result of quantitative data is the percentage of handout product value that classify in the handout quality and the result of qualitative data come from comment and advise of validator and try out in SMK.The result quality of the handout found that the developing contextual basic handout reach out the good quality after following the procedure of validation with percentage 80.90% and try out to the student that use the handout with percentage very good, 97.75% and get the positive respond from student with percentage 90.82%. From the whole of the contextual basic handout have a good quality and appropriate in use for teaching material of Biology in teaching learning process in SMK N 02 Batu.

  13. PENGARUH MODEL PEMBELAJARAN SYNECTICS DIPADU MIND MAPS TERHADAP KEMAMPUAN BERPIKIR KREATIF, SIKAP KREATIF, DAN PENGUASAAN MATERI BIOLOGI

    Directory of Open Access Journals (Sweden)

    Muh Khalifah Mustami

    2007-12-01

    Full Text Available One of the important tasks in teaching is assisting students to think. Synectics Model matched with Mind Maps are viewed necessary to be applied in the instruction in order to achieve the target.The research is an experiment research with pre-test post-test control group design. The results of analyses indicate that: (1 there is significance difference with the mean score of creative think ability, creative attitude, and mastery of biology materials due to difference of instruction model used, (2 there is no significant difference of mean score of creative attitude among the students who belong to the high and low achievement. (3 there is no interactional effect between the instructional model used with the students entry behavior towards creative thinking ability, creative attitude, and mastery of biology materials.

  14. [Accident with biological material at the prehospital mobile care: reality for health and non-healthcare workers].

    Science.gov (United States)

    Tipple, Anaclara Ferreira Veiga; Silva, Elisangelo Aparecido Costa; Teles, Sheila Araújo; Mendonça, Katiane Martins; Souza, Adenícia Custódia Silva E; Melo, Dulcelene Sousa

    2013-01-01

    Analytical transversal study that was conducted with the objectives of identifying the prevalence and characterizing the accidents with biological material among professionals in pre-hospital service (PHS) and comparing the risk behaviors adopted by healthcare and non-healthcare groups that can affect the occurrence and seriousness of such accidents. Data were obtained by questionnaire applied to all PHS workers in Goiânia-GO. The study revealed a high prevalence of accidents involving biological material which, although higher for the healthcare group, also affected the non-healthcare group. There were significant (p accidents in both groups: not using gloves, masks or eye protectors; inappropriate disposal of sharps; inadequate dress; re-capping of needles; and a lack of immunization against hepatitis B. The results underscore the importance of both groups in adhering to preventive measures, and further point to the need to structure and implement vigilance and control system for this type of accident.

  15. Development of analytical methods for the determination of some radiologically important elements in biological materials using neutron activation analysis

    International Nuclear Information System (INIS)

    Dang, H.S.; Jaiswal, D.D.; Pullat, V.R.; Krishnamony, S.

    1998-01-01

    This paper describes the analytical methods developed for the estimation of Cs, I, Sr, Th and U in biological materials such as food and human tissues. The methods employ both, the instrumental neutron activation analysis (INAA) and radiochemical neutron activation analysis (RNAA). The adequacy of these methods to determine the concentrations of the above elements in dietary and tissue materials was also studied. The study showed that the analytical methods described in this paper are adequate for the determination of Cs, Sr, Th and U in all kinds of biological samples. In the case of I however, the method is adequate only for determining its concentration in thyroid, but needs to be modified to improve its sensitivity for the determination of I in diet samples. (author)

  16. Determination of gold and platinum in biological materials by radiochemical neutron activation analysis using electrolytic separation of gold

    International Nuclear Information System (INIS)

    Reitz, B.; Heydorn, K.

    1993-01-01

    A new method is presented for the determination of Au and Pt in biological materials based on neutron activation analysis with radiochemical separation of gold. Separation of gold by electrolytic deposition on a niobium cathode ascertains thee highest radiochemical purity without any interference from calcium or other major elements. With 199 Au as indicator for platinum the gold content of the sample not only strongly affects the limit of detection, but also causes interference by double neutron capture. Replicate analyses of BCR Certified Reference Materials No. 184, 185 and 186 were carried out. (author) 18 refs.; 3 figs.; 2 tabs

  17. Communication of work accidents involving biological material: a study in the city of Santa Cruz do Sul/RS

    Directory of Open Access Journals (Sweden)

    Dayane Diehl

    2012-07-01

    Full Text Available Rationale and Objectives: Healthcare workers are constantly exposed to the risk of occupational accidents involving biological material. Thus the aim of the study was to develop a profile of workers involved in workplace accidents with biological materials in Santa Cruz do Sul, through the number of notifications made in information systems. Methods: Transversal retrospective study with a quantitative approach; data collection was carried out between the years 2008 and 2010 from medical records in the Municipal Reference Occupational Health Unit – UMREST – containing the notification via Individual Report of Accident Notification - RINA, and/or Work Accident Communication - CAT. Results: A total of 1,263 records were analyzed during the study period. There were 13 notifications in 2008, 7 cases in 2009 and 2 in 2010. Five records had CAT, 8 had RINA and 9 had RINA and CAT. The most frequently affected professional category was the nursing technician, with the highest frequency in 2008, followed by dentists and nurses. There was a higher prevalence of female workers, with 18 cases. The most prevalent age group was 20 to 49 years old. Conclusion: The study showed that women working in the nursingprofession at the productive-age group are the ones most often affected by work accidents involving biological material during the study period. The study results raise the suspicion of underreporting of accidents with biological material, considering the number of notifications in thesetting of records found in the investigated UMREST. KEYWORDS Wo rk-related accidents. Health care professional. Occupational accidents.

  18. Two-Dimensional Spectroscopy Is Being Used to Address Core Scientific Questions in Biology and Materials Science.

    Science.gov (United States)

    Petti, Megan K; Lomont, Justin P; Maj, Michał; Zanni, Martin T

    2018-02-15

    Two-dimensional spectroscopy is a powerful tool for extracting structural and dynamic information from a wide range of chemical systems. We provide a brief overview of the ways in which two-dimensional visible and infrared spectroscopies are being applied to elucidate fundamental details of important processes in biological and materials science. The topics covered include amyloid proteins, photosynthetic complexes, ion channels, photovoltaics, batteries, as well as a variety of promising new methods in two-dimensional spectroscopy.

  19. Tunable features of magnetoelectric transformers.

    Science.gov (United States)

    Dong, Shuxiang; Zhai, Junyi; Priya, Shashank; Li, Jie-Fang; Viehland, Dwight

    2009-06-01

    We have found that magnetostrictive FeBSiC alloy ribbons laminated with piezoelectric Pb(Zr,Ti)O(3) fiber can act as a tunable transformer when driven under resonant conditions. These composites were also found to exhibit the strongest resonant magnetoelectric voltage coefficient of 750 V/cm-Oe. The tunable features were achieved by applying small dc magnetic biases of -5 transformer features can be attributed to large changes in the piezomagnetic coefficient and permeability of the magnetostrictive phase under H(dc).

  20. Coherent tunable far infrared radiation

    Science.gov (United States)

    Jennings, D. A.

    1989-01-01

    Tunable, CW, FIR radiation has been generated by nonlinear mixing of radiation from two CO2 lasers in a metal-insulator-metal (MIM) diode. The FIR difference-frequency power was radiated from the MIM diode antenna to a calibrated InSb bolometer. FIR power of 200 nW was generated by 250 mW from each of the CO2 lasers. Using the combination of lines from a waveguide CO2 laser, with its larger tuning range, with lines from CO2, N2O, and CO2-isotope lasers promises complete coverage of the entire FIR band with stepwise-tunable CW radiation.

  1. Multi-objective optimization of a compact pressurized water nuclear reactor computational model for biological shielding design using innovative materials

    Energy Technology Data Exchange (ETDEWEB)

    Tunes, M.A., E-mail: matheus.tunes@usp.br [Department of Metallurgical and Materials Engineering, Escola Politécnica da Universidade de São Paulo, Av. Prof. Mello Moraes, 2463 – CEP 05508 – 030 São Paulo (Brazil); Oliveira, C.R.E. de, E-mail: cassiano@unm.edu [Department of Nuclear Engineering, The University of New Mexico, Farris Engineering Center, 221, Albuquerque, NM 87131-1070 (United States); Schön, C.G., E-mail: schoen@usp.br [Department of Metallurgical and Materials Engineering, Escola Politécnica da Universidade de São Paulo, Av. Prof. Mello Moraes, 2463 – CEP 05508 – 030 São Paulo (Brazil)

    2017-03-15

    Highlights: • Use of two n-γ transport codes leads to optimized model of compact nuclear reactor. • It was possible to safely reduce both weight and volume of the biological shielding. • Best configuration obtained by using new composites for both γ and n attenuation. - Abstract: The aim of the present work is to develop a computational model of a compact pressurized water nuclear reactor (PWR) to investigate the use of innovative materials to enhance the biological shielding effectiveness. Two radiation transport codes were used: the first one – MCNP – for the PWR design and the GEM/EVENT to simulate (in a 1D slab) the behavior of several materials and shielding thickness on gamma and neutron radiation. Additionally MATLAB Optimization Toolbox was used to provide new geometric configurations of the slab aiming at reducing the volume and weight of the walls by means of a cost/objective function. It is demonstrated in the reactor model that the dose rate outside biological shielding has been reduced by one order of magnitude for the optimized model compared with the initial configuration. Volume and weight of the shielding walls were also reduced. The results indicated that one-dimensional deterministic code to reach an optimized geometry and test materials, combined with a three-dimensional model of a compact nuclear reactor in a stochastic code, is a fast and efficient procedure to test shielding performance and optimization before the experimental assessment. A major outcome of this research is that composite materials (ECOMASS 2150TU96) may replace (with advantages) traditional shielding materials without jeopardizing the nuclear power plant safety assurance.

  2. [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.

  3. High sensitivity neutron activation analysis of environmental and biological standard reference materials

    International Nuclear Information System (INIS)

    Greenberg, R.R.; Fleming, R.F.; Zeisler, R.

    1984-01-01

    Neutron activation analysis is a sensitive method with unique capabilities for the analysis of environmental and biological samples. Since it is based upon the nuclear properties of the elements, it does not suffer from many of the chemical effects that plague other methods of analysis. Analyses can be performed either with no chemical treatment of the sample (instrumentally), or with separations of the elements of interest after neutron irradiation (radiochemically). Typical examples of both types of analysis are discussed, and data obtained for a number of environmental and biological SRMs are presented. (author)

  4. Enhanced Electromagnetic and Chemical/Biological Sensing. Properties of Atomic Cluster-Derived Materials

    National Research Council Canada - National Science Library

    Schatz, George

    2003-01-01

    The Center for Atomic Clusters-derived Materials performed a broad range of research concerned with synthesizing, characterizing and utilizing atomic and molecular clusters, nanoparticles and nanomaterial...

  5. Functional polyester materials with tunable degradability: Investigations into the use of reductive amination, ketoxime ether, and hydrazone linkages for functionalization, covalent stabilization and crosslinking of poly(epsilon-caprolactone) materials

    Science.gov (United States)

    van Horn, Brooke Angela

    Aliphatic polyesters represent one class of degradable, polymeric materials that is receiving significant attention in the search for, and design of, biocompatible and bioresorbable synthetic substances. Functional and crosslinked polyesters, having potential biomedical value, are the target of many avenues of current research. This dissertation work expands the utility of a specific aliphatic polyester, poly(epsilon-caprolactone-co-2-oxepane-1,5-dione) (P(CL-co-OPD)), which contains backbone ketone units that can be reacted with various functional, nucleophilic agents. Results presented in this dissertation convey both the successes had and the challenges encountered in the employment of different "iminyl" chemistries for the synthesis of functional and crosslinked materials. Specifically, the ketone-functionalized polyester was investigated as a general substrate designed to undergo solution-state intramolecular crosslinking and functionalization upon reductive amination with 1,6-hexanediamine and hexylamine, respectively, in the presence of NaCNBH3. Through detailed analysis of the products from these reactions, and simpler systems including small molecule model compounds, the polymeric gamma-keto ester functionality was determined to be incompatible with the reductive amination chemistry, resulting in chain cleavage via intramolecular lactam formation. Subsequent investigation of ketoxime ether formation using synthetic model hydroxylamines, 1-aminooxydodecane and 1,6-bis(aminooxy)hexane, in solution and in the presence of an acid catalyst, resulted in the targeted graft and crosslinked particulate/gel materials, respectively. With the significant interest in the development of synthetic polymer materials of increasing degrees of complexity, attention has been focused on the efficient and high-yielding conversion of polyesters into multi-functional materials. Facile conjugation of aminooxy- and sulfonyl hydrazide model ligands with P(CL-co-OPD) were also

  6. Origami structures for tunable thermal expansion

    Science.gov (United States)

    Boatti, Elisa; Bertoldi, Katia

    Materials with engineered thermal expansion, capable of achieving targeted and extreme area/volume changes in response to variations in temperature, are important for a number of aerospace, optical, energy, and microelectronic applications. While most of the proposed structures with tunable coefficient of thermal expansion consist of bi-material 2D or 3D lattices, here we propose a periodic metastructure based on a bilayer Miura-Ori origami fold. We combine experiments and simulations to demonstrate that by tuning the geometrical and mechanical parameters an extremely broad range of thermal expansion coefficients can be obtained, spanning both negative and positive values. Additionally, the thermal properties along different directions can be adjusted independently. Differently from all previously reported systems, the proposed structure is non-porous.

  7. ANALISIS KUALITAS PERAIRAN SUNGAI RAMAN DESA PUJODADI TRIMURJO SEBAGAI SUMBER BELAJAR BIOLOGI SMA PADA MATERI EKOSISTEM

    Directory of Open Access Journals (Sweden)

    Agus Sutanto

    2015-06-01

    Full Text Available River is one of fresh water ecosystem which is very important in human life since it is the most practical and economical source in fulfilling domestic and industrial needs. Therefore, it should meet the quality standards. The research objectives were: 1 knowing the quality of waterway in Raman River, Pujodadi, Trimurjo, based on the physical, chemical and biological aspects; 2 turning the information intoa Biology learning source on Ecosystem subject. The data were directly observed in the river by measuring the physical factors (temperature, stream, turbidity; chemical factors (pH, DO; and biological factor (macro invertebrates. The results were: temperature 24-29oC ; stream 0.3 – 0.6 mm/s; turbidity 33.5-3.7 NTU; pH 4.1-5.2; and DO 2.07-2.35 ml/I. Furthermore, micro vertebrates found were; a Plecoptra; b Tricoptra; c Mollusca, d Ephemeroptra; and e Hemiptra. In each station, they were classified as insects and non-insects. The insects found were: 1 Odonata; 2 Tricoptra; 3 Ephemeroptra; 4 Plecoptra. Based on those parameters, the waterway quality was qualified as light wasted. The results can be turned into student worksheet as a Biology learning source, especially on Ecosystem subject.

  8. Determination of carbon-14 content in biological materials and its application to vinegars

    International Nuclear Information System (INIS)

    Grau Malonda, A.; Martin-Casallo, M.T.; Chereguini, S.

    1976-01-01

    A radiometric method for the determination of synthetic acetic acid in the presence of biological vinegar has been developed. The activity of 1 4C is measured by liquid scintillation counting and the sensitivity is optimized by taking into account the composition of several liquid scintillation solutions and the concentration of their components. (author) [es

  9. 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

  10. Evaluation of biological activities and chemical constituent of storage medicinal plant materials used as a traditional medicine in Nepal

    Directory of Open Access Journals (Sweden)

    Bishnu Prasad Pandey

    2017-12-01

    Full Text Available Aim: The main aims of the study were to evaluate the phytochemicals, antioxidant, antibacterial and chemical constituents of storage medicinal plant materials used as a traditional medicine in Nepal. Methods: Phytochemical screening, total phenolic content, total flavonoid content, antibacterial activities, anti-oxidant assay of the crude extract (water, methanol, n-hexane and acetone were carried out to identify the biological activities and phytonutrients present in the different extract. The chemical constituents present in the crude extract were analyzed using the high performance liquid chromatography (HPLC equipped with UV detector. Results: Evaluated medicinal plant materials were found to have diverse phytonutrients. Results revealed that methanol extract of Pakhanved and Jethimadhu have highest total flavonoids and polyphenol content. Among the selected medicinal plant materials Jethimadhu extract revealed the highest antioxidant activities. Furthermore, evaluated medicinal plants extract were found to exert a range of in vitro growth inhibition activity against both gram positive and gram negative species. The highest antibacterial activities were observed in the case of methanol extract, whereas, least activity was observed with the hexane extract. HPLC analysis of the acetone extract of Jethimadhu reveals the presence of diosmetin. Conclusions: Our result revealed that among the five evaluated medicinal plant materials, Jethimadhu extract revealed biological activities and exhibits a higher amount of polyphenol and flavonoid content. [J Complement Med Res 2017; 6(4.000: 369-377

  11. 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,...

  12. Merton and Ziman's modes of science: the case of biological and similar material transfer agreements

    NARCIS (Netherlands)

    Rodriguez, V.F.

    2007-01-01

    This paper makes a connection between recent studies on research materials exchange and its effect on the progress of science. Academia fears that scientific development could be hampered by the privatised practices of research material exchange. Since post-academic science represents a sufficient

  13. Nanogram determination of arsenic in biological reference materials by non-destructive Compton suppression neutron activation analysis

    International Nuclear Information System (INIS)

    Petra, M.; Landsberger, S.; Swift, G.

    1990-01-01

    Non-destructive epithermal neutron activation analysis in conjunction with Compton suppression has been applied to determine arsenic in seven biological standard reference materials from the National Institute of Standards and Technology. The accuracy is in excellent agreement with all the certified values and compilation results. For four of the materials detection limits between 1-4 ng/g were easily achieved while for three others they ranged from 18-50 ng/g. Overall analytical precision typically varied between 2-4% for five of the reference materials while for two other it was between 12-16%. These methods clearly demonstrate that through a judicious approach of anti-coincidence techniques, nanogram quantities of arsenic can be reliably determined without the need for labor intensive chemical separations. (orig.)

  14. 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.

  15. Tunable electro-optic filter stack

    Science.gov (United States)

    Fontecchio, Adam K.; Shriyan, Sameet K.; Bellingham, Alyssa

    2017-09-05

    A holographic polymer dispersed liquid crystal (HPDLC) tunable filter exhibits switching times of no more than 20 microseconds. The HPDLC tunable filter can be utilized in a variety of applications. An HPDLC tunable filter stack can be utilized in a hyperspectral imaging system capable of spectrally multiplexing hyperspectral imaging data acquired while the hyperspectral imaging system is airborne. HPDLC tunable filter stacks can be utilized in high speed switchable optical shielding systems, for example as a coating for a visor or an aircraft canopy. These HPDLC tunable filter stacks can be fabricated using a spin coating apparatus and associated fabrication methods.

  16. 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.

  17. Element concentrations in candidate biological and environmental reference materials by k0-standardized INAA

    International Nuclear Information System (INIS)

    Freitas, M.C.

    1993-01-01

    K 0 -Based Neutron Activation Analysis (k 0 INAA) was used to analyze the candidate reference materials Apple Leaves and Peach Leaves, and Oriental Tobacco Leaves and Virginia Tobacco Leaves. Concentration values for 27 elements were measured. The accuracy was ascertained by analysis of two certified reference materials. NIST 1572 Citrus Leaves and 1573 Tomato Leaves. The homogeneity test of the IAEA Evernia prunastri candidate reference material in aliquots ≥ 100 mg is extended to the elements Sc, Cr, Fe, Co, Zn, Rb, Sb, Cs, Ba, Ce and Th. (orig.)

  18. Tunable on chip optofluidic laser

    DEFF Research Database (Denmark)

    Bakal, Avraham; Vannahme, Christoph; Kristensen, Anders

    2015-01-01

    A chip scale tunable laser in the visible spectral band is realized by generating a periodic droplet array inside a microfluidic channel. Combined with a gain medium within the droplets, the periodic structure provides the optical feedback of the laser. By controlling the pressure applied to two...

  19. Electrostatically Tunable Nanomechanical Shallow Arches

    KAUST Repository

    Kazmi, Syed N. R.; Hajjaj, Amal Z.; Da Costa, Pedro M. F. J.; Younis, Mohammad I.

    2017-01-01

    -beam lithography and surface nanomachining of a highly conductive device layer on a silicon-on-insulator (SOI) wafer. The experimental results show good agreement with the analytical results with a maximum tunability of 108.14% for 180 nm thick arch with a

  20. Modeling and additive manufacturing of bio-inspired composites with tunable fracture mechanical properties.

    Science.gov (United States)

    Dimas, Leon S; Buehler, Markus J

    2014-07-07

    Flaws, imperfections and cracks are ubiquitous in material systems and are commonly the catalysts of catastrophic material failure. As stresses and strains tend to concentrate around cracks and imperfections, structures tend to fail far before large regions of material have ever been subjected to significant loading. Therefore, a major challenge in material design is to engineer systems that perform on par with pristine structures despite the presence of imperfections. In this work we integrate knowledge of biological systems with computational modeling and state of the art additive manufacturing to synthesize advanced composites with tunable fracture mechanical properties. Supported by extensive mesoscale computer simulations, we demonstrate the design and manufacturing of composites that exhibit deformation mechanisms characteristic of pristine systems, featuring flaw-tolerant properties. We analyze the results by directly comparing strain fields for the synthesized composites, obtained through digital image correlation (DIC), and the computationally tested composites. Moreover, we plot Ashby diagrams for the range of simulated and experimental composites. Our findings show good agreement between simulation and experiment, confirming that the proposed mechanisms have a significant potential for vastly improving the fracture response of composite materials. We elucidate the role of stiffness ratio variations of composite constituents as an important feature in determining the composite properties. Moreover, our work validates the predictive ability of our models, presenting them as useful tools for guiding further material design. This work enables the tailored design and manufacturing of composites assembled from inferior building blocks, that obtain optimal combinations of stiffness and toughness.

  1. Potential of the PIGE method in the analysis of biological and mineral materials

    International Nuclear Information System (INIS)

    Havranek, V.

    2006-01-01

    A possible application of the PIGE method for the analysis of the biological and mineral samples has been tested using a 3.5 MeV Van de Graaff accelerator. The limits of detection of 4 mg/kg for fluorine, 10 mg/kg for aluminium and 200 mg/kg for phosphorus were achieved with a 3.15 MeV proton beam (8 mm in diameter, 20 nA current and 1000 s irradiation time). The PIGE method was found to be a suitable method for the determination of fluorine in the samples analyzed. With this technique, total fluorine in the sample can be quantitated without any chemical treatment. In the analysis of the phosphorus in thick biological samples, PIGE can compete with PIXE and is probably less sensitive to matrix effects and spectra fitting, which may bring about a higher accuracy of the results

  2. Microcantilever technology for law enforcement and anti-terrorism applications: chemical, biological, and explosive material detection

    Science.gov (United States)

    Adams, J. D.; Rogers, B.; Whitten, R.

    2005-05-01

    The remarkable sensitivity, compactness, low cost, low power-consumption, scalability, and versatility of microcantilever sensors make this technology among the most promising solutions for detection of chemical and biological agents, as well as explosives. The University of Nevada, Reno, and Nevada Nanotech Systems, Inc (NNTS) are currently developing a microcantilever-based detection system that will measure trace concentrations of explosives, toxic chemicals, and biological agents in air. A baseline sensor unit design that includes the sensor array, electronics, power supply and air handling has been created and preliminary demonstrations of the microcantilever platform have been conducted. The envisioned device would measure about two cubic inches, run on a small watch battery and cost a few hundred dollars. The device could be operated by untrained law enforcement personnel. Microcantilever-based devices could be used to "sniff out" illegal and/or hazardous chemical and biological agents in high traffic public areas, or be packaged as a compact, low-power system used to monitor cargo in shipping containers. Among the best detectors for such applications at present is the dog, an animal which is expensive, requires significant training and can only be made to work for limited time periods. The public is already accustomed to explosives and metal detection systems in airports and other public venues, making the integration of the proposed device into such security protocols straightforward.

  3. Development and application of an ultratrace method for speciation of organotin compounds in cryogenically archived and homogenized biological materials

    Energy Technology Data Exchange (ETDEWEB)

    Point, David; Davis, W.C.; Christopher, Steven J.; Ellisor, Michael B.; Pugh, Rebecca S.; Becker, Paul R. [Hollings Marine Laboratory, National Institute of Standards and Technology, Analytical Chemistry Division, Charleston, SC (United States); Donard, Olivier F.X. [Laboratoire de Chimie Analytique BioInorganique et Environnement UMR 5034 du CNRS, Pau (France); Porter, Barbara J.; Wise, Stephen A. [National Institute of Standards and Technology, Analytical Chemistry Division, Gaithersburg, MD (United States)

    2007-04-15

    An accurate, ultra-sensitive and robust method for speciation of mono, di, and tributyltin (MBT, DBT, and TBT) by speciated isotope-dilution gas chromatography-inductively coupled plasma-mass spectrometry (SID-GC-ICPMS) has been developed for quantification of butyltin concentrations in cryogenic biological materials maintained in an uninterrupted cryo-chain from storage conditions through homogenization and bottling. The method significantly reduces the detection limits, to the low pg g{sup -1} level (as Sn), and was validated by using the European reference material (ERM) CE477, mussel tissue, produced by the Institute for Reference Materials and Measurements. It was applied to three different cryogenic biological materials - a fresh-frozen mussel tissue (SRM 1974b) together with complex materials, a protein-rich material (whale liver control material, QC03LH03), and a lipid-rich material (whale blubber, SRM 1945) containing up to 72% lipids. The commutability between frozen and freeze-dried materials with regard to spike equilibration/interaction, extraction efficiency, and the absence of detectable transformations was carefully investigated by applying complementary methods and by varying extraction conditions and spiking strategies. The inter-method results enabled assignment of reference concentrations of butyltins in cryogenic SRMs and control materials for the first time. The reference concentrations of MBT, DBT, and TBT in SRM 1974b were 0.92 {+-} 0.06, 2.7 {+-} 0.4, and 6.58 {+-} 0.19 ng g{sup -1} as Sn (wet-mass), respectively; in SRM 1945 they were 0.38 {+-} 0.06, 1.19 {+-} 0.26, and 3.55 {+-} 0.44 ng g{sup -1}, respectively, as Sn (wet-mass). In QC03LH03, DBT and TBT concentrations were 30.0 {+-} 2.7 and 2.26 {+-} 0.38 ng g{sup -1} as Sn (wet-mass). The concentration range of butyltins in these materials is one to three orders of magnitude lower than in ERM CE477. This study demonstrated that cryogenically processed and stored biological materials are

  4. 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

  5. Comparison of Principal Component Analysis and Linear Discriminant Analysis applied to classification of excitation-emission matrices of the selected biological material

    Directory of Open Access Journals (Sweden)

    Maciej Leśkiewicz

    2016-03-01

    Full Text Available Quality of two linear methods (PCA and LDA applied to reduce dimensionality of feature analysis is compared and efficiency of their algorithms in classification of the selected biological materials according to their excitation-emission fluorescence matrices is examined. It has been found that LDA method reduces the dimensions (or a number of significant variables more effectively than PCA method. A relatively good discrimination within the examined biological material has been obtained with the use of LDA algorithm.[b]Keywords[/b]: Feature Analysis, Fluorescence Spectroscopy, Biological Material Classification

  6. Accidental exposure to biological material in healthcare workers at a university hospital: Evaluation and follow-up of 404 cases.

    Science.gov (United States)

    Gutierrez, Eliana Battaggia; Lopes, Marta Heloísa; Yasuda, Maria Aparecida Shikanai

    2005-01-01

    The care and follow-up provided to healthcare workers (HCWs) from a large teaching hospital who were exposed to biological material between 1 August 1998 and 31 January 2002 is described here. After exposure, the HCW is evaluated by a nurse and doctor in an emergency consultation and receives follow-up counselling. The collection of 10 ml of blood sample from each HCW and its source patient, when known, is made for immunoenzymatic testing for HIV, HBV and HCV. Evaluation and follow-up of 404 cases revealed that the exposures were concentrated in only a few areas of the hospital; 83% of the HCWs exposed were seen by a doctor responsible for the prophylaxis up to 3 h after exposure. Blood was involved in 76.7% (309) of the exposures. The patient source of the biological material was known in 80.7% (326) of the exposed individuals studied; 80 (24.5%) sources had serological evidence of infection with 1 or more agents: 16.2% were anti-HCV positive, 3.8% were HAgBs positive and 10.9% were anti-HIV positive. 67% (273) of the study population completed the proposed follow-up. No confirmed seroconversion occurred. In conclusion, the observed adherence to the follow-up was quite low, and measures to improve it must be taken. Surprisingly, no difference in adherence to the follow-up was observed among those exposed HCW at risk, i.e. those with an infected or unknown source patient. Analysis of post-exposure management revealed excess prescription of antiretroviral drugs, vaccine and immunoglobulin. Infection by HCV is the most important risk of concern, in our hospital, in accidents with biological material.

  7. Biological cell as a soft magnetoelectric material: Elucidating the physical mechanisms underpinning the detection of magnetic fields by animals

    Science.gov (United States)

    Krichen, S.; Liu, L.; Sharma, P.

    2017-10-01

    Sharks, birds, bats, turtles, and many other animals can detect magnetic fields. Aside from using this remarkable ability to exploit the terrestrial magnetic field map to sense direction, a subset is also able to implement a version of the so-called geophysical positioning system. How do these animals detect magnetic fields? The answer to this rather deceptively simple question has proven to be quite elusive. The currently prevalent theories, while providing interesting insights, fall short of explaining several aspects of magnetoreception. For example, minute magnetic particles have been detected in magnetically sensitive animals. However, how is the detected magnetic field converted into electrical signals given any lack of experimental evidence for relevant electroreceptors? In principle, a magnetoelectric material is capable of converting magnetic signals into electricity (and vice versa). This property, however, is rare and restricted to a rather small set of exotic hard crystalline materials. Indeed, such elements have never been detected in the animals studied so far. In this work we quantitatively outline the conditions under which a biological cell may detect a magnetic field and convert it into electrical signals detectable by biological cells. Specifically, we prove the existence of an overlooked strain-mediated mechanism and show that most biological cells can act as nontrivial magnetoelectric materials provided that the magnetic permeability constant is only slightly more than that of a vacuum. The enhanced magnetic permeability is easily achieved by small amounts of magnetic particles that have been experimentally detected in magnetosensitive animals. Our proposed mechanism appears to explain most of the experimental observations related to the physical basis of magnetoreception.

  8. Synthesis and biological evaluation of PMMA/MMT nanocomposite as denture base material.

    Science.gov (United States)

    Zheng, Junping; Su, Qiang; Wang, Chen; Cheng, Gang; Zhu, Ran; Shi, Jin; Yao, Kangde

    2011-04-01

    Inorganic-polymer nanocomposites are of significant interest for emerging materials due to their improved properties and unique combination of properties. Poly (methylmethacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were prepared by in situ suspension polymerization with dodecylamine used as MMT-modifier. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the structures of the nanocomposites. Cytotoxicity test, hemolysis test, acute systemic toxicity test, oral mucous membrane irritation test, guinea-pig maximization test and mouse bone-marrow micronucleus test were used to evaluate the biocompatibility of PMMA/MMT nanocomposites. The results indicated that an exfoliated nanocomposite was achieved, and the resulting nanocomposites exhibited excellent biocompatibility as denture base material and had potential application in dental materials.

  9. Using Synthetic Biology to Engineer Living Cells That Interface with Programmable Materials.

    Science.gov (United States)

    Heyde, Keith C; Scott, Felicia Y; Paek, Sung-Ho; Zhang, Ruihua; Ruder, Warren C

    2017-03-09

    We have developed an abiotic-biotic interface that allows engineered cells to control the material properties of a functionalized surface. This system is made by creating two modules: a synthetically engineered strain of E. coli cells and a functionalized material interface. Within this paper, we detail a protocol for genetically engineering selected behaviors within a strain of E. coli using molecular cloning strategies. Once developed, this strain produces elevated levels of biotin when exposed to a chemical inducer. Additionally, we detail protocols for creating two different functionalized surfaces, each of which is able to respond to cell-synthesized biotin. Taken together, we present a methodology for creating a linked, abiotic-biotic system that allows engineered cells to control material composition and assembly on nonliving substrates.

  10. 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

  11. New classes of tough composite materials-Lessons from natural rigid biological systems

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, G. [Department of Materials Science and Engineering, Box 352120, University of Washington, Seattle, WA 98195-2120 (United States)]. E-mail: gmayer@u.washington.edu

    2006-09-15

    The structures and properties of a new class of composite materials, containing a predominantly high volume fraction ceramic or glass phase, combined with minor organic (adhesive) phases, have been studied. These composites have unusual combinations of mechanical properties, such as stiffness, strength, and toughness. They are based on the architecture of a rigid natural material, the nacre structure, such as those found in the shells of the abalone Haliotis rufescens, and those of other mollusk shells. The mechanisms underlying these properties have also been studied. Analogs (utilizing high-performance engineering materials), that mimic many of the mechanisms underlying those superior combinations of properties, have been built. The results of the foregoing investigations are discussed. It was found that the toughness of segmented composite beams which have high volume fractions of ceramic (89 v / o) exceeded those of continuous layered beams, as well as the monolithic ceramic (alumina) on which they are based.

  12. New classes of tough composite materials-Lessons from natural rigid biological systems

    International Nuclear Information System (INIS)

    Mayer, G.

    2006-01-01

    The structures and properties of a new class of composite materials, containing a predominantly high volume fraction ceramic or glass phase, combined with minor organic (adhesive) phases, have been studied. These composites have unusual combinations of mechanical properties, such as stiffness, strength, and toughness. They are based on the architecture of a rigid natural material, the nacre structure, such as those found in the shells of the abalone Haliotis rufescens, and those of other mollusk shells. The mechanisms underlying these properties have also been studied. Analogs (utilizing high-performance engineering materials), that mimic many of the mechanisms underlying those superior combinations of properties, have been built. The results of the foregoing investigations are discussed. It was found that the toughness of segmented composite beams which have high volume fractions of ceramic (89 v / o) exceeded those of continuous layered beams, as well as the monolithic ceramic (alumina) on which they are based

  13. The use of a single technique for the separation and determination of actinides in biological materials

    International Nuclear Information System (INIS)

    Camera, V.; Giubileo.

    1975-01-01

    For the radiotoxicological survey of workers exposed to different types of alpha-emitting contaminants, a procedure was developed which permits the estimate of Th, Pa, U, Np, Pu, Am and Cm in biological samples with a single technique. The radionuclides are extracted on a column by tri-n-octylphosphine oxide and separated by elution at different pH values. Afterwards, the quantitative determinations are done by physical methods (alpha counting or spectrometry). In the case of an accident it is possible to use a simplification of the procedure (extraction in a beaker) for checks. A procedure for the rapid determination of actinides in faeces and in nasal secretions is described

  14. INAA applied to halogen (Br and I) stability in long-term storage of lyophilized biological materials

    International Nuclear Information System (INIS)

    Zaichick, V.; Zaichick, S.

    2000-01-01

    Instrumental neutron activation analysis (INAA) was used to determine the Br and I concentration in the same ten lyophilized and homogenized human thyroid samples prior and after a 20-year storage at room temperature. It was found that long-term storage had no effect on the iodine content. At the same time, the bromine content was about 2-fold lower (p<0.01). It was assumed that possible losses of other halogens can occur under long-term storage of lyophilized biological materials at room temperature. (author)

  15. Determination of trace elements in Brazilian rice grains and in biological reference materials by neutron activation analysis

    International Nuclear Information System (INIS)

    Maihara, V.A.; Vasconcellos, M.B.A.

    1989-01-01

    Instrumental neutron activation analysis was applied to the determination of the elements Na, K, Br, As, Rb, Zn, Co, Fe and Sc in Brazilian rice samples and in biological standards. Hg and Se concentrations were determined by using a simple radiochemical separation. The chemical procedure was carried out by means of distillation of Hg and Se in HBr medium and subsequent precipitation of selenium by sodium methabissulfide and mercury by thioacetamide. The accuracy of the instrumental and radiochemical methods was evaluated by means of analysis of the Reference Materials NBS-Bovine Liver, Bowen's Kale and NBS-Rice Flour. (author) [pt

  16. Determination of trace elements in Brazilian rice grains and in biological reference materials by neutron activation analysis

    International Nuclear Information System (INIS)

    Maihara, V.A.; Vasconcellos, M.B.A.

    1989-01-01

    INAA was applied to the determination of the elements Na, K, Br, As, Rb, Zn, Co, Fe and Sc in Brazilian rice samples and in biological standards. Hg and Se concentrations were determined using a simple radiochemical separation. The chemical procedure was carried out by means of distillation of Hg and Se in HBr medium and subsequent precipitation of Se by sodium metabisulfite and Hg by thioacetamide. The accuracy of the instrumental and radiochemical methods was evaluated by means of analysis of the Reference Materials NBS-Bovine Liver, Bowen's Kale and NBS-Rice Flour. (author) 15 refs.; 5 tabs

  17. Visible tunable source

    International Nuclear Information System (INIS)

    1987-10-01

    We planned four tasks for the second phase of this project; these are: study the effect of different grating materials; study the effect of different grating shapes; study the effect of anisotropic conductivity, and optimize the resonator configuration. Because the measurement techniques involved in the first two tasks are similar, the studies on different grating materials and shapes are discussed together. We are conducting two more experiments which were not originally planned. An experiment with a high current pulsed e-beam generator is presented and a measurement of radiation as a function of beam thickness is reported

  18. Comparison between liquid and solid tunable focus lenses

    International Nuclear Information System (INIS)

    Santiago-Alvarado, A; Cruz-Martinez, V M; Vazquez-Montiel, S; Munoz-Lopez, J; Diaz-Gonzalez, G; Campos-Garcia, M

    2011-01-01

    Nowadays more reports in the use of tunable lenses are reported, it is due to the benefits they offer in optical systems design. A tunable lens is an optical system that can focus on a range of positions by changing dynamically one of its geometric parameters. There are several types of tunable lenses, the most known types are the liquid, the solid elastic, with variable refractive index, and lenses that use a dielectric medium. This paper presents the analysis and opto-mechanical design of two tunable lenses, a liquid lens and another Solid Elastic Lens (SEL). Both lenses are made in mounting aluminium and polydimethylsiloxane (PDMS) as refractor medium, the liquid lens use two elastic membranes containing a liquid medium between them while the SEL only use PDMS material as body of the lens (medium refractor). We describe the opto-mechanical performance of both types of lens highlighting the main features of each. Finally, results of a opto-functional comparison between these prototypes are showed.

  19. The double radio-isotope derivative techniques for the assay of drugs in biological material

    International Nuclear Information System (INIS)

    Riess, W.

    1977-01-01

    The neuroleptic drug opipramol and its deshydroxyethyl metabolite can be determined simultaneously in the same biological sample. Known amounts of 14 C-labelled opipramol and 14 C-labelled metabolite are added to the sample to serve as internal standards. After suitable extraction, both compounds are acetylated by 3 H-labelled acetic anhydride. Together with μg-amounts of carrier compounds, the O-acetyl derivative of opipramol and the N-acetyl derivative of the metabolite are purified and separated by two-dimensional thin-layer chromatography. Each of the derivatives is isolated and counted for 14 C- and 3 H-activity. The 14 C-activities recovered serve to determine the overall yield of the opipramol and metabolite, and to convert the measured 3 H-activity to 100% theoretical yield. From analyses of standard samples, the specific 3 H-activities of the acetyl derivatives were calculated and these values were used to convert the measured 3 H-activites from biological samples to concentrations of original opipramol and metabolite. For both compounds the standard deviations of blank samples were +- 1 ng/ml. For concentrations up to 100 ng/ml the standard deviation was +- 3 ng/ml

  20. Graphene: One Material, Many Possibilities—Application Difficulties in Biological Systems

    Directory of Open Access Journals (Sweden)

    Marta Skoda

    2014-01-01

    Full Text Available Energetic technologies, nanoelectronics, biomedicine including gene therapy, cell imaging or tissue engineering are only few from all possible applications for graphene, the thinnest known carbon configuration and a basic element for other more complicated, better discovered and widely used nanostructures such as graphite, fullerenes and carbon nanotubes. The number of researches concerning graphene applications is rising every day which proves the great interest in its unique structure and properties. Ideal pristine graphene sheet presents a flat membrane of unlimited size with no imperfections while in practice we get different flakes with irregular edges and structural defects which influence the reactivity. Nanomaterials from graphene family differ in size, shape, layer number, lateral dimension, surface chemistry and defect density causing the existence of graphene samples with various influence on biological systems. Whether graphene induces cellular stress and activates apoptosis, or on the contrary facilitates growth and differentiation of the cells depends on its structure, chemical modifications and the growth process. A certain number of in vitro studies has indicated cytotoxic effects of graphene while the other show that it is safe. The diversity of the samples and methods of the production make it impossible to establish clearly the biological impact of graphene.

  1. Synthesis of Precision for the Certification of Phosphorus in Biological Materials by INAA

    DEFF Research Database (Denmark)

    Damsgaard, E.; Heydorn, K.

    1987-01-01

    The β-emitter32P was used to determine total phosphorus by INAA in Skim Milk Powder RM 63, a material now certified by the EEC Bureau of Reference (BCR). Samples and comparator were irradiated in the Danish reactor DR 3. One month later the samples were dissolved in water and aliquots counted...

  2. Compilation of elemental concentration data for NBS Biological and Environmental Standard Reference Materials

    International Nuclear Information System (INIS)

    Gladney, E.S.

    1980-07-01

    Concentration data on up to 76 elementals in 19 NBS Standard Reference Materials have been collected from 325 journal articles and technical reports. These data are summarized into mean +- one standard deviation values and compared with available data from NBS and other review articles. Data are presented on the analytical procedures employed and all raw data are presented in appendixes

  3. Electrospun Fibers as a Dressing Material for Drug and Biological Agent Delivery in Wound Healing Applications

    Science.gov (United States)

    Gizaw, Mulugeta; Thompson, Jeffrey; Faglie, Addison; Lee, Shih-Yu; Neuenschwander, Pierre; Chou, Shih-Feng

    2018-01-01

    Wound healing is a complex tissue regeneration process that promotes the growth of new tissue to provide the body with the necessary barrier from the outside environment. In the class of non-healing wounds, diabetic wounds, and ulcers, dressing materials that are available clinically (e.g., gels and creams) have demonstrated only a slow improvement with current available technologies. Among all available current technologies, electrospun fibers exhibit several characteristics that may provide novel replacement dressing materials for the above-mentioned wounds. Therefore, in this review, we focus on recent achievements in electrospun drug-eluting fibers for wound healing applications. In particular, we review drug release, including small molecule drugs, proteins and peptides, and gene vectors from electrospun fibers with respect to wound healing. Furthermore, we provide an overview on multifunctional dressing materials based on electrospun fibers, including those that are capable of achieving wound debridement and wound healing simultaneously as well as multi-drugs loading/types suitable for various stages of the healing process. Our review provides important and sufficient information to inform the field in development of fiber-based dressing materials for clinical treatment of non-healing wounds. PMID:29382065

  4. Intercomparison of enriched stable isotope reference materials for medical and biological studies

    International Nuclear Information System (INIS)

    Parr, R.M.; Clements, S.A.

    1991-01-01

    This report summarizes the results of an intercomparison exercise organized by the IAEA during the latter part of 1988 and 1989. Data are presented for 13 different kinds of enriched stable isotope reference material containing 2 H, 13 C, 15 N and 18 O. Results were submitted by forty participants in twenty countries. 2 refs, 13 figs, 18 tabs

  5. MAK and BAT values list 2014. Maximum permissible concentrations at the place of work and biological tolerance values for working materials; MAK- und BAT-Werte-Liste 2014. Maximale Arbeitsplatzkonzentrationen und Biologische Arbeitsstofftoleranzwerte

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-11-01

    The book on the MAK (maximum permissible concentrations at the place of work) and BAT (biological tolerance values for working materials) value list 2014 includes the following chapters: (a) Maximum permissible concentrations at the place of work: definition, application and determination of MAT values, list of materials; carcinogenic working materials, sensibilizing working materials, aerosols, limiting the exposition peaks, skin resorption, MAK values during pregnancy, germ cell mutagens, specific working materials; (b) Biological tolerance values for working materials: definition and application of BAT values, list of materials, carcinogenic working materials, biological guide values, biological working material reference values.

  6. MAK and BAT values list 2013. Maximum permissible concentrations at the place of work and biological tolerance values for working materials; MAK- und BAT-Werte-Liste 2013. Maximale Arbeitsplatzkonzentrationen und Biologische Arbeitsstofftoleranzwerte

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-01

    The book on the MAK (maximum permissible concentrations at the place of work) and BAT (biological tolerance values for working materials) value list 2013 includes the following chapters: (a) Maximum permissible concentrations at the place of work: definition, application and determination of MAT values, list of materials; carcinogenic working materials, sensibilizing working materials, aerosols, limiting the exposition peaks, skin resorption, MAK values during pregnancy, germ cell mutagens, specific working materials; (b) Biological tolerance values for working materials: definition and application of BAT values, list of materials, carcinogenic working materials, biological guide values, biological working material reference values.

  7. MAK and BAT values list 2015. Maximum permissible concentrations at the place of work and biological tolerance values for working materials; MAK- und BAT-Werte-Liste 2015. Maximale Arbeitsplatzkonzentrationen und Biologische Arbeitsstofftoleranzwerte

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-11-01

    The book on the MAK (maximum permissible concentrations at the place of work) and BAT (biological tolerance values for working materials) value list 2015 includes the following chapters: (a) Maximum permissible concentrations at the place of work: definition, application and determination of MAT values, list of materials; carcinogenic working materials, sensibilizing working materials, aerosols, limiting the exposition peaks, skin resorption, MAK values during pregnancy, germ cell mutagens, specific working materials; (b) Biological tolerance values for working materials: definition and application of BAT values, list of materials, carcinogenic working materials, biological guide values, biological working material reference values.

  8. Determination of Sr, Ba, Rb, and Cs in biological reference materials using a radiochemical NAA group separation procedure

    International Nuclear Information System (INIS)

    Mizera, J.; Randa, Z.

    2008-01-01

    Strontium, barium, rubidium, and cesium in selected, predominantly biological, reference materials (NIST 1515, 1547, 1549, 1566a, 1571, 1577b, 2704, CTA-OTL-1, and Bowen's Kale) were determined using neutron activation analysis (NAA) in two different analytical modes - instrumental NAA with epithermal neutrons (ENAA), and NAA with radiochemical group separation of Sr-Ba and Rb-Cs (RNAA). The ENAA mode was based on long-term (5 h) irradiation of samples in a Cd shielding. The RNAA procedure was based on long-term (20 h) irradiation of samples, their decomposition / dissolution by alkaline-oxidative fusion, and precipitation of Sr and Ba sulfates, and sorption of Rb and Cs onto ammonium phosphomolybdate (APM). Both methods provided element contents in the analyzed reference materials consistent with certified and/or literature values. (author)

  9. 2012 best practices for repositories collection, storage, retrieval, and distribution of biological materials for research international society for biological and environmental repositories.

    Science.gov (United States)

    2012-04-01

    Third Edition [Formula: see text] [Box: see text] Printed with permission from the International Society for Biological and Environmental Repositories (ISBER) © 2011 ISBER All Rights Reserved Editor-in-Chief Lori D. Campbell, PhD Associate Editors Fay Betsou, PhD Debra Leiolani Garcia, MPA Judith G. Giri, PhD Karen E. Pitt, PhD Rebecca S. Pugh, MS Katherine C. Sexton, MBA Amy P.N. Skubitz, PhD Stella B. Somiari, PhD Individual Contributors to the Third Edition Jonas Astrin, Susan Baker, Thomas J. Barr, Erica Benson, Mark Cada, Lori Campbell, Antonio Hugo Jose Froes Marques Campos, David Carpentieri, Omoshile Clement, Domenico Coppola, Yvonne De Souza, Paul Fearn, Kelly Feil, Debra Garcia, Judith Giri, William E. Grizzle, Kathleen Groover, Keith Harding, Edward Kaercher, Joseph Kessler, Sarah Loud, Hannah Maynor, Kevin McCluskey, Kevin Meagher, Cheryl Michels, Lisa Miranda, Judy Muller-Cohn, Rolf Muller, James O'Sullivan, Karen Pitt, Rebecca Pugh, Rivka Ravid, Katherine Sexton, Ricardo Luis A. Silva, Frank Simione, Amy Skubitz, Stella Somiari, Frans van der Horst, Gavin Welch, Andy Zaayenga 2012 Best Practices for Repositories: Collection, Storage, Retrieval and Distribution of Biological Materials for Research INTERNATIONAL SOCIETY FOR BIOLOGICAL AND ENVIRONMENTAL REPOSITORIES (ISBER) INTRODUCTION T he availability of high quality biological and environmental specimens for research purposes requires the development of standardized methods for collection, long-term storage, retrieval and distribution of specimens that will enable their future use. Sharing successful strategies for accomplishing this goal is one of the driving forces for the International Society for Biological and Environmental Repositories (ISBER). For more information about ISBER see www.isber.org . ISBER's Best Practices for Repositories (Best Practices) reflect the collective experience of its members and has received broad input from other repository professionals. Throughout this document

  10. Electro-optical tunable birefringent filter

    Science.gov (United States)

    Levinton, Fred M [Princeton, NJ

    2012-01-31

    An electrically tunable Lyot type filter is a Lyot that include one or more filter elements. Each filter element may have a planar, solid crystal comprised of a material that exhibits birefringence and is electro-optically active. Transparent electrodes may be coated on each face of the crystal. An input linear light polarizer may be located on one side of the crystal and oriented at 45 degrees to the optical axis of the birefringent crystal. An output linear light polarizer may be located on the other side of the crystal and oriented at -45 degrees with respect to the optical axis of the birefringent crystal. When an electric voltage is applied between the electrodes, the retardation of the crystal changes and so does the spectral transmission of the optical filter.

  11. Tunable Magnetic Resonance in Microwave Spintronics Devices

    Science.gov (United States)

    Chen, Yunpeng; Fan, Xin; Xie, Yunsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

    2015-01-01

    Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe based tunable microwave spintronics devices, which is 10X higher than conventional methods.

  12. Quantum information storage using tunable flux qubits

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, Matthias; Brito, Frederico; DiVincenzo, David; Farinelli, Matthew; Keefe, George; Ketchen, Mark; Kumar, Shwetank; Milliken, Frank; Rothwell, Mary Beth; Rozen, Jim; Koch, Roger H, E-mail: msteffe@us.ibm.co [IBM Watson Research Center, Yorktown Heights, NY 10598 (United States)

    2010-02-10

    We present details and results for a superconducting quantum bit (qubit) design in which a tunable flux qubit is coupled strongly to a transmission line. Quantum information storage in the transmission line is demonstrated with a dephasing time of T{sub 2}approx2.5 mus. However, energy lifetimes of the qubit are found to be short (approx10 ns) and not consistent with predictions. Several design and material changes do not affect qubit coherence times. In order to determine the cause of these short coherence times, we fabricated standard flux qubits based on a design which was previously successfully used by others. Initial results show significantly improved coherence times, possibly implicating losses associated with the large size of our qubit. (topical review)

  13. Tunable plasmonic lattices of silver nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Andrea; Sinsermsuksakul, Prasert; Yang, Peidong

    2008-02-18

    Silver nanocrystals are ideal building blocks for plasmonicmaterials that exhibit a wide range of unique and potentially usefuloptical phenomena. Individual nanocrystals display distinct opticalscattering spectra and can be assembled into hierarchical structures thatcouple strongly to external electromagnetic fields. This coupling, whichis mediated by surface plasmons, depends on their shape and arrangement.Here we demonstrate the bottom-up assembly of polyhedral silvernanocrystals into macroscopic two-dimensional superlattices using theLangmuir-Blodgett technique. Our ability to control interparticlespacing, density, and packing symmetry allows for tunability of theoptical response over the entire visible range. This assembly strategyoffers a new, practical approach to making novel plasmonic materials forapplication in spectroscopic sensors, sub-wavelength optics, andintegrated devices that utilize field enhancement effects.

  14. Tunable 'optical activity' in electrorheological fluids

    International Nuclear Information System (INIS)

    Zhao, Q.; Zhao, X.P.

    2005-01-01

    The 'optical activity' of adjustable periodic structure material (SiO 2 and pentaerythrital electrorheological (ER) fluids) is firstly investigated using two kinds of setup. It is found that the rotation angles can be tuned by the external electric field and weight concentrations, and the sign of the rotation angle is negative, so, the used ER fluids are defined as the left-handed optically active substances under the application of electric field. The laser diffraction patterns are also observed in the ER fluids, which indicates the formation of alignment. It is thought that the symmetry breaking of structure induced by applied electric field is the origin of the 'optical activity' in the ER fluids. The electrically tunable 'optical activity' will find innovative applications in displays, optical devices and other fields

  15. Nanostructured electrocatalysts with tunable activity and selectivity

    Science.gov (United States)

    Mistry, Hemma; Varela, Ana Sofia; Kühl, Stefanie; Strasser, Peter; Cuenya, Beatriz Roldan

    2016-04-01

    The field of electrocatalysis has undergone tremendous advancement in the past few decades, in part owing to improvements in catalyst design at the nanoscale. These developments have been crucial for the realization of and improvement in alternative energy technologies based on electrochemical reactions such as fuel cells. Through the development of novel synthesis methods, characterization techniques and theoretical methods, rationally designed nanoscale electrocatalysts with tunable activity and selectivity have been achieved. This Review explores how nanostructures can be used to control electrochemical reactivity, focusing on three model reactions: O2 electroreduction, CO2 electroreduction and ethanol electrooxidation. The mechanisms behind nanoscale control of reactivity are discussed, such as the presence of low-coordinated sites or facets, strain, ligand effects and bifunctional effects in multimetallic materials. In particular, studies of how particle size, shape and composition in nanostructures can be used to tune reactivity are highlighted.

  16. The standardisation of trace elements in international biological standard reference materials with neutron activation analysis and atomic absorption spectrophotometry

    International Nuclear Information System (INIS)

    Pieterse, H.

    1981-12-01

    An investigation was undertaken into the analytical procedures and the identification of problem areas, for the certification of a new biological standard reference material supplied by the International Atomic Energy Agency, namely, a human hair sample designated as HH-I. The analyses comprised the determination of the elements As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Sb, Se, and Zn in the hair sample by using two analytical techniques, namely, Instrumental Neutron Activation Analysis and Atomic Absorption. Three other certified biological reference materials, namely, Orchard Leaves (ORCH-L), Sea Plant Material (SPM-I) and Copepod (MAA-I) were used as control standards. Determinations were made of the moisture content of the samples, using varying conditions of drying, and the necessary corrections were applied to all analytical results so that the final elemental values related to dry weight of samples. Attention was also given to the possible loss of specific elements during ashing of the samples prior to the actual instrumental analysis. The results obtained for the hair sample by the two techniques were in good agreement for the elements Co, Fe, Mn, and Zn, but did not agree for the elements Cr and Sb. As, Hg and Se could only be determined with Instrumental Neutron Activation Analysis, and Cd, Cu and Ni only with Atomic Absorption. Most of the results obtained for the three control standard reference materials were within the ranges specified for the individual elements in each sample. The analytical procedures used for determining Cd, Cr, Cu, Ni and Sb with Instrumental Neutron Activation Analysis and As, Cr, Sb and Se with Atomic Absorption, need further investigation. The measurement of the moisture content and the ashing of samples also require further investigation with a view to improving accuracy

  17. Material balance and diets in biological life support systems: a relationship with a coefficient of closure

    Science.gov (United States)

    Manukovsky, N. S.; Kovalev, V. S.; Somova, L. A.

    Biological life support systems (BLSS) of various coefficients of closure were considered The basic coefficient of closure was accepted equal to 66%. With increase in coefficient of closure food requirements for the greater degree should be satisfied due to the manufacture of food inside the BLSS. In this connection food values were estimated both in the basic variant, and in those with increased coefficients of closure. Metabolic massflow rates were estimated at the input and output of the BLSS as well as inside it. Human massflow rates were submitted on the basis of characteristics of the 'reference man'. Stoichiometric synthesis - degradation equations of organic substances in the BLSS were obtained. A problem of nitrogen imbalance was shown to occur under an incomplete BLSS closure. To compensate losses of nitrogen with urine and feces, food and nitrogen-containing additives should be introduced into the BLSS.

  18. Atomic force microscopy applied to study macromolecular content of embedded biological material

    Energy Technology Data Exchange (ETDEWEB)

    Matsko, Nadejda B. [Electron Microscopy Centre, Institute of Applied Physics, HPM C 15.1, ETH-Hoenggerberg, CH-8093, Zurich (Switzerland)]. E-mail: matsko@iap.phys.ethz.ch

    2007-02-15

    We demonstrate that atomic force microscopy represents a powerful tool for the estimation of structural preservation of biological samples embedded in epoxy resin, in terms of their macromolecular distribution and architecture. The comparison of atomic force microscopy (AFM) and transmission electron microscopy (TEM) images of a biosample (Caenorhabditis elegans) prepared following to different types of freeze-substitution protocols (conventional OsO{sub 4} fixation, epoxy fixation) led to the conclusion that high TEM stainability of the sample results from a low macromolecular density of the cellular matrix. We propose a novel procedure aimed to obtain AFM and TEM images of the same particular organelle, which strongly facilitates AFM image interpretation and reveals new ultrastructural aspects (mainly protein arrangement) of a biosample in addition to TEM data.

  19. Materials of 4. international meeting on pulse investigations in physics, chemistry and biology. PULS'94

    International Nuclear Information System (INIS)

    1994-01-01

    4. International Meeting on Pulse Investigations in Physics, Chemistry and Biology, PULS'94 has been organized in honor of Professor Jerzy Kroh, the precursor of radiation chemistry in Poland. The meeting has been divided into three sessions: the historical session (H) with four review lectures, lecture session (L) collected 23 papers and poster session (P) with 39 posters. The fundamental studies on early stages of radiolysis have been presented for different systems being irradiated. The pulse radiolysis and flash photolysis methods has been predominantly used in reported experimental works. The reaction of intermediate products of radiolysis and photolysis such a trapped and solvated electrons, ions and radicals has been extensively studied. The reaction mechanisms and kinetics have been also discussed

  20. Determination of mercury and selenium in biological materials by neutron activation analysis method

    International Nuclear Information System (INIS)

    Catharino, Marilia G.M.; Vasconcellos, Marina B.A.; Moreira, Edson G.; Cipriano, Roseli; Saiki, Mitiko

    2000-01-01

    Mercury presents a great number of applications, however, many mercury compounds are highly toxic and may cause diseases or even death. Other element of interest is selenium, as some studies have shown that it may reduce the toxic effects of mercury and other toxic elements, due to its ability to bind to these elements. In this work the mercury concentration in the 'Spiked Human Hair' IAEA-085 and 'Unspiked Human Hair' IAEA-086 certified reference materials, in hair samples of children under dental treatment and in hair samples of an Amazon Region population, subject to mercurial contamination was determined. Selenium determination was done using 77m Se and 75 Se radioisotopes. The selenium concentration was determined also in the (IAEA-085, IAEA-086, 'Dogfish Liver' DOLT-1 and 'Dogfish Muscle' DORM-1) certified reference materials, vitamin supplement and nail clipping samples. (author)

  1. Homogeneity study on biological candidate reference materials: the role of neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Daniel P.; Moreira, Edson G., E-mail: dsilva.pereira@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Instrumental Neutron activation Analysis (INAA) is a mature nuclear analytical technique able to accurately determine chemical elements without the need of sample digestion and, hence, without the associated problems of analyte loss or contamination. This feature, along with its potentiality use as a primary method of analysis, makes it an important tool for the characterization of new references materials and in the assessment of their homogeneity status. In this study, the ability of the comparative method of INAA for the within-bottle homogeneity of K, Mg, Mn and V in a mussel reference material was investigated. Method parameters, such as irradiation time, sample decay time and distance from sample to the detector were varied in order to allow element determination in subsamples of different sample masses in duplicate. Sample masses were in the range of 1 to 250 mg and the limitations of the detection limit for small sample masses and dead time distortions for large sample masses were investigated. (author)

  2. Analytical scheme for group separation of the lanthanides from biological materials before their determination by Neutron Activation Analysis

    International Nuclear Information System (INIS)

    Danko, B.; Samczynski, Z.; Dybczynski, R.

    2006-01-01

    The analytical procedure for the selective and quantitative isolation of the lanthanides as a group from biological materials has been developed on the basis of experiments with radio-tracers. Ion exchange and extraction column chromatography were used for the isolation of elements of interest from matrix and the other trace elements prior to irradiation in a nuclear reactor. The method enables quantitative separation of the lanthanide fraction, free from highly activating macro components, as well as from other trace elements including uranium, which can be the source of serious errors due to uranium 235 U fission reaction (n,f). In order to minimize the potential spectrometric interferences lanthanide fraction after neutron irradiation was divided into two sub-fractions, taking advantage of the different anion exchange affinities of individual lanthanide complexes with EDTA to strongly basic anion exchanger. The effective microwave digestion procedures for ca 500 mg biological samples was elaborated and the new, original method for checking the yield of the entire analytical procedure - including mineralization of the sample - was applied. Neutron activation analysis (NAA) of BCR 670 Aquatic Plant ? one of the only two CRMs of biological origin available on the market, which offers the certified values for all lanthanides was used for verification of performance of the proposed analytical scheme. (authors)

  3. Laser desorption/ionization mass spectrometry for direct profiling and imaging of small molecules from raw biological materials

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Sangwon [Iowa State Univ., Ames, IA (United States)

    2008-01-01

    Matrix-assisted laser desorption/ionization(MALDI) mass spectrometry(MS) has been widely used for analysis of biological molecules, especially macromolecules such as proteins. However, MALDI MS has a problem in small molecule (less than 1 kDa) analysis because of the signal saturation by organic matrixes in the low mass region. In imaging MS (IMS), inhomogeneous surface formation due to the co-crystallization process by organic MALDI matrixes limits the spatial resolution of the mass spectral image. Therefore, to make laser desorption/ionization (LDI) MS more suitable for mass spectral profiling and imaging of small molecules directly from raw biological tissues, LDI MS protocols with various alternative assisting materials were developed and applied to many biological systems of interest. Colloidal graphite was used as a matrix for IMS of small molecules for the first time and methodologies for analyses of small metabolites in rat brain tissues, fruits, and plant tissues were developed. With rat brain tissues, the signal enhancement for cerebroside species by colloidal graphite was observed and images of cerebrosides were successfully generated by IMS. In addition, separation of isobaric lipid ions was performed by imaging tandem MS. Directly from Arabidopsis flowers, flavonoids were successfully profiled and heterogeneous distribution of flavonoids in petals was observed for the first time by graphite-assisted LDI(GALDI) IMS.

  4. Sustainable Materials Management (SMM) Web Academy Webinar: Compost from Food Waste: Understanding Soil Chemistry and Soil Biology on a College/University Campus

    Science.gov (United States)

    This page contains information about the Sustainable Materials Management (SMM) Web Academy Webinar Series titled Compost from Food Waste:Understanding Soil Chemistry and Soil Biology on a College/University Campus

  5. Biological evaluation of zirconia/PEG hybrid materials synthesized via sol–gel technique

    Energy Technology Data Exchange (ETDEWEB)

    Catauro, M., E-mail: michelina.catauro@unina2.it [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa (Italy); Papale, F.; Bollino, F. [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa (Italy); Gallicchio, M.; Pacifico, S. [Department Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta (Italy)

    2014-07-01

    The objective of the following study has been the synthesis via sol–gel and the characterization of novel organic–inorganic hybrid materials to be used in biomedical field. The prepared materials consist of an inorganic zirconia matrix containing as organic component the polyethylene glycol (PEG), a water-soluble polymer used in medical and pharmaceutical fields. Various hybrids have been synthesized changing the molar ratio between the organic and inorganic parts. Fourier transform spectroscopy suggests that the structure of the interpenetrating network is realized by hydrogen bonds between the Zr-OH group in the sol–gel intermediate species and both the terminal alcoholic group and ethereal oxygen atoms in the repeating units of polymer The amorphous nature of the gels has been ascertained by X-ray diffraction analysis. The morphology observation has been carried out by using the Scanning Electron Microscope and has confirmed that the obtained materials are nanostructurated hybrids. The bioactivity of the synthesized system has been shown by the formation of a hydroxyapatite layer on the surface of samples soaked in a fluid simulating the human blood plasma. The potential biocompatibility of hybrids has been assessed as performing indirect MTT cytotoxicity assay towards 3T3 cell line at 24, 48, and 72 h exposure times. - Highlights: • ZrO{sub 2}/PEG amorphous class I organic–inorganic hybrid synthesis via sol–gel • Bioactivity evaluation of materials by the formation of apatite on surface in SBF • Biocompatibility test with indirect MTT cytotoxicity assay on NHI 3T3 cell line.

  6. Procurement of a Nanoindenter for Structure-Function Analyses of Biologically Inspired High Performance Composite Materials

    Science.gov (United States)

    2012-01-13

    abalone shell (Figures 3, 4). Here, we can see that the damage is significantly mitigated in the nacreous regions while cracks formed in the Calcitic...properties. Page 5 / 11 Identifying the crack propagation mechanisms helps to identify new designs for impact resistant materials, so the...human tooth from dentin – dentin/ enamel junction – enamel . It is clear that higher resolution scans are necessary to interrogate local structure

  7. Biological evaluation of zirconia/PEG hybrid materials synthesized via sol–gel technique

    International Nuclear Information System (INIS)

    Catauro, M.; Papale, F.; Bollino, F.; Gallicchio, M.; Pacifico, S.

    2014-01-01

    The objective of the following study has been the synthesis via sol–gel and the characterization of novel organic–inorganic hybrid materials to be used in biomedical field. The prepared materials consist of an inorganic zirconia matrix containing as organic component the polyethylene glycol (PEG), a water-soluble polymer used in medical and pharmaceutical fields. Various hybrids have been synthesized changing the molar ratio between the organic and inorganic parts. Fourier transform spectroscopy suggests that the structure of the interpenetrating network is realized by hydrogen bonds between the Zr-OH group in the sol–gel intermediate species and both the terminal alcoholic group and ethereal oxygen atoms in the repeating units of polymer The amorphous nature of the gels has been ascertained by X-ray diffraction analysis. The morphology observation has been carried out by using the Scanning Electron Microscope and has confirmed that the obtained materials are nanostructurated hybrids. The bioactivity of the synthesized system has been shown by the formation of a hydroxyapatite layer on the surface of samples soaked in a fluid simulating the human blood plasma. The potential biocompatibility of hybrids has been assessed as performing indirect MTT cytotoxicity assay towards 3T3 cell line at 24, 48, and 72 h exposure times. - Highlights: • ZrO 2 /PEG amorphous class I organic–inorganic hybrid synthesis via sol–gel • Bioactivity evaluation of materials by the formation of apatite on surface in SBF • Biocompatibility test with indirect MTT cytotoxicity assay on NHI 3T3 cell line

  8. Biological Effects of Provisional Resin Materials on Human Dental Pulp Stem Cells.

    Science.gov (United States)

    Jun, S-K; Mahapatra, C; Lee, H-H; Kim, H-W; Lee, J-H

    This study investigated the in vitro cytotoxicity as well as the proinflammatory cytokine expression of provisional resin materials on primary cultured human dental pulp stem cells (hDPSCs). Five commercially available provisional resin materials were chosen (SNAP [SN], Luxatemp [LT], Jet [JE], Revotek LC [RL], and Vipi block [VB]). Eluates that were either polymerizing or already set were added to hDPSCs under serially diluted conditions divided into three different setting times (25% set, 50% set, and 100% set) and incubated for 24 hours with 2× concentrated culture media. Cell cytotoxicity tests were performed by LDH assay and live and dead confocal microscope images. The expression of proinflammatory cytokines in SN and VB was measured using cytokine antibody arrays. Data were analyzed using repeated measures analysis of variance (ANOVA) or ANOVA followed by the Tukey post hoc test at a significance level of pprovisional resin materials during polymerization (SN, LT, and JE) were cytotoxic to hDPSCs and may adversely affect pulp tissue.

  9. Negative stiffness honeycombs as tunable elastic metamaterials

    Science.gov (United States)

    Goldsberry, Benjamin M.; Haberman, Michael R.

    2018-03-01

    Acoustic and elastic metamaterials are media with a subwavelength structure that behave as effective materials displaying atypical effective dynamic properties. These material systems are of interest because the design of their sub-wavelength structure allows for direct control of macroscopic wave dispersion. One major design limitation of most metamaterial structures is that the dynamic response cannot be altered once the microstructure is manufactured. However, the ability to modify wave propagation in the metamaterial with an external stimulus is highly desirable for numerous applications and therefore remains a significant challenge in elastic metamaterials research. In this work, a honeycomb structure composed of a doubly periodic array of curved beams, known as a negative stiffness honeycomb (NSH), is analyzed as a tunable elastic metamaterial. The nonlinear static elastic response that results from large deformations of the NSH unit cell leads to a large variation in linear elastic wave dispersion associated with infinitesimal motion superposed on the externally imposed pre-strain. A finite element model is utilized to model the static deformation and subsequent linear wave motion at the pre-strained state. Analysis of the slowness surface and group velocity demonstrates that the NSH exhibits significant tunability and a high degree of anisotropy which can be used to guide wave energy depending on static pre-strain levels. In addition, it is shown that partial band gaps exist where only longitudinal waves propagate. The NSH therefore behaves as a meta-fluid, or pentamode metamaterial, which may be of use for applications of transformation elastodynamics such as cloaking and gradient index lens devices.

  10. Ecological evaluation of proposed dredged material from the John F. Baldwin Ship Channel: Phase 3 -- biological testing

    Energy Technology Data Exchange (ETDEWEB)

    Kohn, N.P.; Karle, L.M.; Pinza, M.R.; Mayhew, H.L.; White, P.J.; Gruendell, B.D.; Word, J.Q. [Battelle/Marine Sciences Lab., Sequim, WA (United States)

    1993-10-01

    The John F. Baldwin Ship Channel is a 28-mile-long portion of the San Francisco Bay to Stockton Ship Channel, the primary shipping lane through San Francisco Bay and Delta. The San Francisco District of the US Army Corps of Engineers (USACE) is responsible for construction of the John F. Baldwin Ship Channel, which is authorized to be deepened to a project depth of {minus}45 ft relative to mean lower low water (MLLW). Approximately 8.5 million cubic yards (mcy) of sediment will be removed from the channel to reach this project depth. The USACE requested Battelle/Marine Sciences Laboratory (MSL) to conduct testing for ocean disposal under the guidelines in Evaluation of Dredged Material Proposed for Ocean Disposal-Testing Manual (EPA/USACE 1991). This testing manual contains a tiered evaluation approach developed specifically for ocean disposal of dredged material at a selected site. In this study, John F. Baldwin Ship Channel sediments were evaluated under the Tier III (biological) testing guidance, which is considered to be highly stringent and protective of the environment. The Tier III guidance for ocean disposal testing requires tests of water column effects, (following dredged material disposal), deposited sediment toxicity, and bioaccumulation of contaminants from deposited sediment (dredged material).

  11. 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

  12. Diretrizes nacionais para biorrepositório e biobanco de material biológico humano Brazilian guidelines for biorepositories and biobanks of human biological material

    Directory of Open Access Journals (Sweden)

    Gabriela Marodin

    2013-02-01

    Full Text Available OBJETIVO: Caracterizar a construção participativa e democrática das Diretrizes Nacionais para Biorrepositório e Biobanco de Material Biológico Humano com Finalidade de Pesquisa, baseada nos princípios éticos da dignidade humana, da autonomia, da beneficência, da justiça e da precaução. MÉTODOS: Para a elaboração do documento formou-se um grupo de trabalho interdisciplinar Bioética considerando os seguintes critérios: experiência na operacionalização de biobancos, Biobancos representatividade regional, tipo de material biológico acondicionado e especialistas em Biorrepositório bioética. Participaram, também, membros da Agência Nacional de Vigilância Sanitária Diretrizes - Anvisa, pela competência regulatória e da Comissão Nacional de Ética em Pesquisa - Conep, enquanto controle social. RESULTADOS: O documento, baseado nos preceitos éticos, legais e técnicos, apresenta os conceitos, as atividades, finalidades e diferenças entre biorrepositórios e biobancos, as formas de consentimento do sujeito, além de outros aspectos permeados pela preocupação do uso adequado da informação. As Diretrizes Nacionais para Biorrepositório e Biobanco de Material Biológico Humano com Finalidade de Pesquisa contém 39 artigos, dispostos em cinco capítulos. CONCLUSÃO: A importância de uma regulamentação surge da reflexão ética, considerando a moral, e tendo como norteador os aspectos legais, os quais se traduzem em um documento que não se esgota em si mesmo. A dinamicidade da ciência sempre nos remete à mudança de paradigmas, que podem ir além das legislações existentes.OBJECTIVE: To characterize the participatory and democratic creation of the Brazilian guidelines for biorepositories and biobanks of human biological material with the purpose of research based on the ethical principles of human dignity, autonomy, beneficence, justice, and precaution. METHODS: An interdisciplinary work group was constituted to

  13. Hidden biodiversity in entomological collections: The overlooked co-occurrence of dipteran and hymenopteran ant parasitoids in stored biological material.

    Directory of Open Access Journals (Sweden)

    Gabriela Pérez-Lachaud

    Full Text Available Biological collections around the world are the repository of biodiversity on Earth; they also hold a large quantity of unsorted, unidentified, or misidentified material and can house behavioral information on species that are difficult to access or no longer available to science. Among the unsorted, alcohol-preserved material stored in the Formicidae Collection of the 'El Colegio de la Frontera Sur' Research Center (Chetumal, Mexico, we found nine colonies of the ponerine ant Neoponera villosa, that had been collected in bromeliads at Calakmul (Campeche, Mexico in 1999. Ants and their brood were revised for the presence of any sign of parasitism. Cocoons were dissected and their content examined under a stereomicroscope. Six N. villosa prepupae had been attacked by the ectoparasitoid syrphid fly Hypselosyrphus trigonus Hull (Syrphidae: Microdontinae, to date the only known dipteran species of the Microdontinae with a parasitoid lifestyle. In addition, six male pupae from three colonies contained gregarious endoparasitoid wasps. These were specialized in parasitizing this specific host caste as no gyne or worker pupae displayed signs of having been attacked. Only immature stages (larvae and pupae of the wasp could be obtained. Due to the long storage period, DNA amplification failed; however, based on biological and morphological data, pupae were placed in the Encyrtidae family. This is the first record of an encyrtid wasp parasitizing N. villosa, and the second example of an encyrtid as a primary parasitoid of ants. Furthermore, it is also the first record of co-occurrence of a dipteran ectoparasitoid and a hymenopteran endoparasitoid living in sympatry within the same population of host ants. Our findings highlight the importance of biological collections as reservoirs of hidden biodiversity, not only at the taxonomic level, but also at the behavioral level, revealing complex living networks. They also highlight the need for funding in order

  14. Hidden biodiversity in entomological collections: The overlooked co-occurrence of dipteran and hymenopteran ant parasitoids in stored biological material.

    Science.gov (United States)

    Pérez-Lachaud, Gabriela; Lachaud, Jean-Paul

    2017-01-01

    Biological collections around the world are the repository of biodiversity on Earth; they also hold a large quantity of unsorted, unidentified, or misidentified material and can house behavioral information on species that are difficult to access or no longer available to science. Among the unsorted, alcohol-preserved material stored in the Formicidae Collection of the 'El Colegio de la Frontera Sur' Research Center (Chetumal, Mexico), we found nine colonies of the ponerine ant Neoponera villosa, that had been collected in bromeliads at Calakmul (Campeche, Mexico) in 1999. Ants and their brood were revised for the presence of any sign of parasitism. Cocoons were dissected and their content examined under a stereomicroscope. Six N. villosa prepupae had been attacked by the ectoparasitoid syrphid fly Hypselosyrphus trigonus Hull (Syrphidae: Microdontinae), to date the only known dipteran species of the Microdontinae with a parasitoid lifestyle. In addition, six male pupae from three colonies contained gregarious endoparasitoid wasps. These were specialized in parasitizing this specific host caste as no gyne or worker pupae displayed signs of having been attacked. Only immature stages (larvae and pupae) of the wasp could be obtained. Due to the long storage period, DNA amplification failed; however, based on biological and morphological data, pupae were placed in the Encyrtidae family. This is the first record of an encyrtid wasp parasitizing N. villosa, and the second example of an encyrtid as a primary parasitoid of ants. Furthermore, it is also the first record of co-occurrence of a dipteran ectoparasitoid and a hymenopteran endoparasitoid living in sympatry within the same population of host ants. Our findings highlight the importance of biological collections as reservoirs of hidden biodiversity, not only at the taxonomic level, but also at the behavioral level, revealing complex living networks. They also highlight the need for funding in order to carry out

  15. Niobium pentoxide as radiopacifying agent of calcium silicate-based material: evaluation of physicochemical and biological properties.

    Science.gov (United States)

    Silva, Guilherme F; Tanomaru-Filho, Mário; Bernardi, Maria I B; Guerreiro-Tanomaru, Juliane M; Cerri, Paulo S

    2015-11-01

    The physicochemical properties and the tissue reaction promoted by microparticulated or nanoparticulated niobium pentoxide (Nb2O5) added to calcium silicate-based cement (CS), compared to MTA-Angelus™, were evaluated. Materials were submitted to the tests of radiopacity, setting time, pH, and calcium ion release. Polyethylene tubes filled with the materials were implanted into rats subcutaneously. After 7, 15, 30, and 60 days, the specimens were fixed and embedded in paraffin. Hematoxylin & eosin (H&E)-stained sections were used to compute the number of inflammatory cells (IC). Interleukin-6 (IL-6) detection was performed, and the number of immunolabeled cells was obtained; von Kossa method was also carried out. Data were subjected to ANOVA and Tukey test (p ≤ 0.05). Nb2O5micro and Nb2O5nano provided to the CS radiopacity values (3.52 and 3.75 mm Al, respectively) superior to the minimum recommended. Groups containing Nb2O5 presented initial setting time significantly superior than mineral trioxide aggregate (MTA). All materials presented an alkaline pH and released calcium ions. The number of IC and IL-6 immunolabeled cells in the CS + Nb2O5 groups was significantly reduced in comparison to MTA in all periods. von Kossa-positive structures were observed adjacent to implanted materials in all periods. The addition of Nb2O5 to the CS resulted in a material biocompatible and with adequate characteristics regarding radiopacity and final setting time and provides an alkaline pH to the environment. Furthermore, the particle size did not significantly affect the physicochemical and biological properties of the calcium silicate-based cement. Niobium pentoxide can be used as radiopacifier for the development of calcium silicate-based materials.

  16. Highly tunable NEMS shallow arches

    KAUST Repository

    Kazmi, Syed N. R.

    2017-11-30

    We report highly tunable nanoelectromechanical systems NEMS shallow arches under dc excitation voltages. Silicon based in-plane doubly clamped bridges, slightly curved as shallow arches, are fabricated using standard electron beam lithography and surface nanomachining of a highly conductive device layer on a silicon-on-insulator wafer. By designing the structures to have gap to thickness ratio of more than four, the mid-plane stretching of the nano arches is maximized such that an increase in the dc bias voltage will result into continuous increase in the resonance frequency of the resonators to wide ranges. This is confirmed analytically based on a nonlinear beam model. The experimental results are found to be in good agreement with that of the results from developed analytical model. A maximum tunability of 108.14% for a 180 nm thick arch with an initially designed gap of 1 μm between the beam and the driving/sensing electrodes is achieved. Furthermore, a tunable narrow bandpass filter is demonstrated, which opens up opportunities for designing such structures as filtering elements in high frequency ranges.

  17. Highly Tunable Electrostatic Nanomechanical Resonators

    KAUST Repository

    Kazmi, Syed Naveed Riaz

    2017-11-24

    There has been significant interest towards highly tunable resonators for on-demand frequency selection in modern communication systems. Here, we report highly tunable electrostatically actuated silicon-based nanomechanical resonators. In-plane doubly-clamped bridges, slightly curved as shallow arches due to residual stresses, are fabricated using standard electron beam lithography and surface nanomachining. The resonators are designed such that the effect of mid-plane stretching dominates the softening effect of the electrostatic force. This is achieved by controlling the gap-to-thickness ratio and by exploiting the initial curvature of the structure from fabrication. We demonstrate considerable increase in the resonance frequency of nanoresonators with the dc bias voltages up to 108% for 180 nm thick structures with a transduction gap of 1 $mu$m separating them from the driving/sensing electrodes. The experimental results are found in good agreement with those of a nonlinear analytical model based on the Euler-Bernoulli beam theory. As a potential application, we demonstrate a tunable narrow band-pass filter using two electrically coupled nanomechanical arch resonators with varied dc bias voltages.

  18. Highly Tunable Electrostatic Nanomechanical Resonators

    KAUST Repository

    Kazmi, Syed Naveed Riaz; Hajjaj, Amal Z.; Hafiz, Md Abdullah Al; Da Costa, Pedro M. F. J.; Younis, Mohammad I.

    2017-01-01

    There has been significant interest towards highly tunable resonators for on-demand frequency selection in modern communication systems. Here, we report highly tunable electrostatically actuated silicon-based nanomechanical resonators. In-plane doubly-clamped bridges, slightly curved as shallow arches due to residual stresses, are fabricated using standard electron beam lithography and surface nanomachining. The resonators are designed such that the effect of mid-plane stretching dominates the softening effect of the electrostatic force. This is achieved by controlling the gap-to-thickness ratio and by exploiting the initial curvature of the structure from fabrication. We demonstrate considerable increase in the resonance frequency of nanoresonators with the dc bias voltages up to 108% for 180 nm thick structures with a transduction gap of 1 $mu$m separating them from the driving/sensing electrodes. The experimental results are found in good agreement with those of a nonlinear analytical model based on the Euler-Bernoulli beam theory. As a potential application, we demonstrate a tunable narrow band-pass filter using two electrically coupled nanomechanical arch resonators with varied dc bias voltages.

  19. Additive manufacturing of tunable lenses

    Science.gov (United States)

    Schlichting, Katja; Novak, Tobias; Heinrich, Andreas

    2017-02-01

    Individual additive manufacturing of optical systems based on 3D Printing offers varied possibilities in design and usage. In addition to the additive manufacturing procedure, the usage of tunable lenses allows further advantages for intelligent optical systems. Our goal is to bring the advantages of additive manufacturing together with the huge potential of tunable lenses. We produced tunable lenses as a bundle without any further processing steps, like polishing. The lenses were designed and directly printed with a 3D Printer as a package. The design contains the membrane as an optical part as well as the mechanical parts of the lens, like the attachments for the sleeves which contain the oil. The dynamic optical lenses were filled with an oil. The focal length of the lenses changes due to a change of the radius of curvature. This change is caused by changing the pressure in the inside of the lens. In addition to that, we designed lenses with special structures to obtain different areas with an individual optical power. We want to discuss the huge potential of this technology for several applications. Further, an appropriate controlling system is needed. Wéll show the possibilities to control and regulate the optical power of the lenses. The lenses could be used for illumination tasks, and in the future, for individual measurement tasks. The main advantage is the individuality and the possibility to create an individual design which completely fulfills the requirements for any specific application.

  20. Conjugation of nano and quantum materials with bovine serum albumin (BSA) to study their biological potential

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Suman, E-mail: sumansingh01@gmail.com [Central Scientific Instruments Organisation (CSIR-CSIO), Chandigarh (India); Kaur, Rajnish; Chahal, Jitender; Devi, P. [Central Scientific Instruments Organisation (CSIR-CSIO), Chandigarh (India); Jain, D.V.S. [Panjab University, Chandigarh (India); Singla, M.L., E-mail: singla_min@yahoo.co.in [Central Scientific Instruments Organisation (CSIR-CSIO), Chandigarh (India)

    2013-09-15

    Conjugates of gold nanoparticles (AuNPs) and semiconductor quantum dots (CdS/T) have been synthesized with bovine serum albumin (BSA) using wet chemistry. The optical properties of nano and quantum materials and their BSA conjugate have been studied using UV–Visible and Fluorescence spectroscopy. UV–Visible spectrum of pure BSA showed an absorption maximum at 278 nm, which showed blue shift after its conjugation with nano and quantum materials. Increased concentration of AuNPs during conjugation resulted in broadening of BSA peak (278 nm), which can be related to the formation of ground state complex formation, caused by the partial adsorption of BSA on the surface of NPs. However, increased concentrations of BSA resulted in decrease in SPR intensity of gold nanoparticles (528 nm) and absorbance peak of BSA started diminishing. AuNPs acted as quencher for BSA fluorescence intensity, when excited at 280 nm. The binding constant (K) and the number of binding sites (n) between AuNPs and BSA have been found to be 1.97×10{sup 2} LM{sup −1} and 0.6 respectively. With quantum dots, conjugation resulted in enhancement of fluorescence emission of quantum dots when excited at 300 nm, which might be due to the stabilizing effect of BSA on QDs or due to energy transfer from tryptophan moieties of albumin to quantum dots. -- Highlights: • Synthesis of nanoparticles (AuNPs) and quantum dots (CdS). • Conjugation of these materials with bovine serum albumin. • Optical behavioral studies.

  1. Bioprospecting finds the toughest biological material: extraordinary silk from a giant riverine orb spider.

    Directory of Open Access Journals (Sweden)

    Ingi Agnarsson

    Full Text Available BACKGROUND: Combining high strength and elasticity, spider silks are exceptionally tough, i.e., able to absorb massive kinetic energy before breaking. Spider silk is therefore a model polymer for development of high performance biomimetic fibers. There are over 41,000 described species of spiders, most spinning multiple types of silk. Thus we have available some 200,000+ unique silks that may cover an amazing breadth of material properties. To date, however, silks from only a few tens of species have been characterized, most chosen haphazardly as model organisms (Nephila or simply from researchers' backyards. Are we limited to 'blindly fishing' in efforts to discover extraordinary silks? Or, could scientists use ecology to predict which species are likely to spin silks exhibiting exceptional performance properties? METHODOLOGY: We examined the biomechanical properties of silk produced by the remarkable Malagasy 'Darwin's bark spider' (Caerostris darwini, which we predicted would produce exceptional silk based upon its amazing web. The spider constructs its giant orb web (up to 2.8 m(2 suspended above streams, rivers, and lakes. It attaches the web to substrates on each riverbank by anchor threads as long as 25 meters. Dragline silk from both Caerostris webs and forcibly pulled silk, exhibits an extraordinary combination of high tensile strength and elasticity previously unknown for spider silk. The toughness of forcibly silked fibers averages 350 MJ/m(3, with some samples reaching 520 MJ/m(3. Thus, C. darwini silk is more than twice tougher than any previously described silk, and over 10 times better than Kevlar®. Caerostris capture spiral silk is similarly exceptionally tough. CONCLUSIONS: Caerostris darwini produces the toughest known biomaterial. We hypothesize that this extraordinary toughness coevolved with the unusual ecology and web architecture of these spiders, decreasing the likelihood of bridgelines breaking and collapsing the web

  2. BIOLOGICAL AND SYNTHETIC MATERIALS IN RECONSTRUCTIVE SURGERY FOR BREAST CANCER TREATMENT (LITERATURE REVIEW

    Directory of Open Access Journals (Sweden)

    A. D. Zikiryakhodzhaev

    2018-01-01

    Full Text Available During the last years has been a worldwide trend towards rejuvenating breast cancer, and the evolution of reconstructive breast surgery is proceeding at a rapid pace. The surgical method is the primary method in the combined and complex treatment of breast cancer, and radical mastectomy is still the main option for surgical treatment in most Russian clinics. Most women who need a mastectomy prefer a one-stage breast reconstruction, because the woman is quickly rehabilitated psychologically and physically after this operation. Nevertheless, the use of silicone endoprostheses did not solve the problems of breast reconstruction in combined treatment in oncology. The issue remains unresolved of various complications, related not only to infections, but also to the development of capsular contracture after radiotherapy. Many patients with a one-stage breast reconstruction using a silicone endoprostheses lack the volume of their own tissues for reliable shelter of the endoprosthesis. In such cases, synthetic reticulated implants, biological implants or autologous flaps are used to cover and strengthen the lower slope of the reconstructed breast.

  3. Preparation and biological evaluation of a fibroblast growth factor-2-apatite composite layer on polymeric material

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Kenkichi; Kamitakahara, Masanobu; Ioku, Koji [Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Oyane, Ayako [Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Hyodo, Koji [Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564 (Japan); Ito, Atsuo; Sogo, Yu, E-mail: a-oyane@aist.go.j [Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8566 (Japan)

    2010-12-15

    A polymeric percutaneous device with good biocompatibility and resistance to bacterial infection is required clinically. In this study, a fibroblast growth factor-2 (FGF-2)-hydroxyapatite (HAp) composite layer (FHAp layer) was formed on the surfaces of ethylene-vinyl alcohol copolymer (EVOH) specimens using a coating process in a supersaturated calcium phosphate solution supplemented with FGF-2. FGF-2 in the FHAp layer retained its biological activity to promote proliferation of fibroblasts. The EVOH specimens coated with HAp and FHAp layers were percutaneously implanted in the scalp of rats. Not only the HAp layer but also the FHAp layer showed good biocompatibility, and FGF-2 showed no harmful effects on the skin tissue responses to the implanted specimen as long as 14 d. No significantly higher infection resistance was verified for the FHAp layer over the HAp layer, although an FHAp layer coated on a metallic percutaneous device for bone fixation demonstrated higher resistance to bacterial infection over an HAp layer in the previous study. The efficacy of FHAp layers coated on percutaneous implants in resistance to bacterial infection depends on physical factors including fixation condition, stiffness and movement of implants.

  4. Composites with mechanically tunable plasmon frequency

    International Nuclear Information System (INIS)

    Schuil, Crystal J; Amirkhizi, Alireza V; Bayatpur, Farhad; Nemat-Nasser, Sia

    2011-01-01

    This paper summarizes our efforts to create a composite material with a mechanically tunable plasmon frequency at the microwave band. The permittivity of the composite changes sign at the plasmon frequency. Such composites, therefore, can be used as electromagnetic filters. Theoretically, an array of non-magnetic, metallic wire coils has been shown to have a plasmon behavior that is dependent on the wire thickness, coil inner diameter, pitch and coil spacing. Here, a material is made out of an array of coils placed within a non-metallic frame, and the material plasmon frequency is tuned through altering the pitch. The coils are arranged with alternating handedness to create an effective, non-chiral medium. A transmit/receive setup is used to characterize the electromagnetic behavior of the composite. The setup consists of a vector network analyzer and two horn antennas, which are used to measure the scattering parameters of the material. These parameters are then used to calculate the permittivity. The results show an increase in the plasmon frequency with increase in the pitch. Increasing the pitch 30%, from 3 to 3.9 mm, results in a corresponding increase from 6.3 to 7.5 GHz in the frequency

  5. [Alternative biological materials to detect prenatal exposure to drugs of abuse in the third trimester of pregnancy].

    Science.gov (United States)

    García-Serra, J; Ramis, J; Simó, S; Joya, X; Pichini, S; Vall, O; García-Algar, O

    2012-11-01

    Detection of prenatal drug abuse exposure is essential to ensure an appropriate monitoring of affected children. A maternal questionnaire is not an efficient screening tool. The usefulness of maternal hair and meconium as biological materials to assess this exposure has been described in last few years. The aim of this study was to compare both these alternative biological materials for prenatal drug exposure detection in the third trimester of pregnancy, in order to assess its use as a screening tool. Between January and March 2010, samples of maternal hair and meconium from 107 mother-infant dyads were collected in Can Misses Hospital, Ibiza. The presence of opiates, cocaine, cannabis, and amphetamines, was determined in both materials, using standard chromatographic techniques. Maternal hair analysis showed a 15.9% positivity for drugs of abuse (17 cases): 11 cannabis, 7 cocaine, 1 cannabis and ecstasy, and 1 cannabis and cocaine. Only one mother reported cannabis consumption and another one, cocaine. Of the 7 cocaine positive cases in hair, 6 were confirmed in meconium analysis, while of 11 cannabis positive cases, only 3 were confirmed in meconium. Two different consumer profiles were defined: cocaine consumers and cannabis consumers (with only 2 cases of multiple drug use). The highest level of cocaine ever published was detected (1.582ng/g) in one case. This study reveals a high prevalence of drug abuse in this cohort during pregnancy. Improved screening methods may optimize prevention and monitoring of exposed infants. Maternal hair seems to be more sensitive than meconium to detect prenatal exposure to cannabis during the third trimester, so it might become a good screening tool. Copyright © 2011 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  6. Antenna Miniaturization with MEMS Tunable Capacitors

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Morris, Art; Pedersen, Gert Frølund

    2014-01-01

    In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss and their characterist......In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss...

  7. Voltage-controlled colour-tunable microcavity OLEDs with enhanced colour purity

    International Nuclear Information System (INIS)

    Choy, Wallace C H; Niu, J H; Li, W L; Chui, P C

    2008-01-01

    The emission spectrum of single-unit voltage-controlled colour-tunable organic light emitting devices (OLEDs) has been theoretically and experimentally studied. Our results show that by introducing the microcavity structure, the colour purity of not only the destination colour but also the colour-tunable route can be enhanced, while colour purity is still an issue in typical single-unit voltage-controlled colour-tunable OLEDs. With the consideration of the periodical cycling of resonant wavelength and absorption loss of the metal electrodes, the appropriate change in the thickness of the microcavity structure has been utilized to achieve voltage-controlled red-to-green and red-to-blue colour-tunable OLEDs without adding dyes or other organic materials to the OLEDs

  8. Berstein's anti-reductionistic materialism: On the road towards a biology of activity (1965).

    Science.gov (United States)

    Bongaardt, R; Pickenhain, L; Meijer, O G

    2000-10-01

    Bernstein's paper, "On the Road Towards a Biology of Activity," appeared the year before his death.2 With this paper, Bernstein closed several lines of argument that he had been developing from the onset of his career in the early 1920s. The paper converges on the notion of activity. In accordance with his own shifting focus heuristic (cf. Bongaardt, 1996), Bernstein challenged future researchers of movement to integrate models of the movement functions that constitute activity. He suggested that these functions are: the coordination of movement, the planning of movement, and the exploration of better, optimal ways to move. In the 1920s, Bernstein had collaborated with his friend and colleague L.S. Vygotsky at the Moscow Institute of Experimental Psychology. Vygotsky (cf. 1926/1994) was the first to place activity at the core of Soviet psychology. According to Vygotsky, reflexology and behaviorism, then dominant approaches in psychology, were fundamentally wrong; they focus on building-blocks of behavior without addressing phenomena that stand out as typically human, most importantly, consciousness. Rather than starting with building blocks, psychology should start with the daily activity of human beings in their environment and show how this activity relates to consciousness. Forty years later, in his 1965 paper, Bernstein stressed a point that mirrors Vygotsky's: Reflexes are not building blocks of movement. The general characteristics of any movement precede the specificity of such units, whether reflexes or synergies, and this primacy pertains to the actual organization of movements as well as to the study of movement. The development and relevance of the activity concept in Bernstein's work in the period from 1925 to 1965 deserves a study of its own; here, a brief historical sketch of Bernstein's activity concept is offered, along with a few theoretical considerations concerning activity's constituent functions.

  9. IDENTIFIKASI NEMATODA PARASIT PADA SALURAN PENCERNAAN MARMUT (Cavia cobaya SEBAGAI SUMBER BELAJAR BIOLOGI PADA MATERI INVERTEBRATA

    Directory of Open Access Journals (Sweden)

    Septia Nurhasanah

    2014-05-01

    Full Text Available The research was conducted in the Laboratory of Science Education, University of Muhammadiyah Metro. The research is a descriptive analysis, morphological observations were made by identifying the nematode parasite found that Trichostrongylus sp, Strongyloides sp, Trichuris sp, Trichuris sp. The results showed the prevalence and intensity values is the large number of guinea pigs to parasites divided by the number of guinea pigs that are 100% inspected. While the intensity is seen from the total number of nematode parasites that infect in the number of guinea pigs infected with a parasite that is 2,3. The population in this study was 10 cows pigs (Cavia cobaya . This study took a part in the digestion of marmots (Cavia cobaya the intestines and stomach , then cut and taken part in the large intestine and be Indian ink or coloring 2-3 drops to be easily identified microscopically . Put the preparations into a petri dish , and given alcohol as much as 96 % with 2-3 drops . Taking part in the examination of the large intestine to taste then used the nematode worm structure with Indian ink dye to be observed , and placed in the glass object . Observed with a microscope. Document if the parasites are found by using the camera Erlina 2008. Identification of the observations made have found 3 types of parasites that attack the guinea pig (Cavia cobaya is Strongyloides sp on samples 1,2,3,4,5,6 , dan10 . Then parasite Trichuris sp species found in samples 8 and 9. Trichostrongylus sp parasite species found in sample 7 . Parasitic nematodes found were 3 types of Trichostrongylus sp, Strongyloides sp, Trichuris sp. Number of samples that have been observed as many as 10 cows pigs (Cavia cobaya , with the overall result is as much as 23 tails parasites.               Kata kunci: nematode parasit, marmut (Cavia cobaya, sumber belajar biologi.

  10. Accidents with potentially hazardous biological material among workers in hospital supporting services.

    Science.gov (United States)

    Canini, Silvia Rita Marin da Silva; Gir, Elucir; Machado, Alcyone Artiolli

    2005-01-01

    Descriptive study was carried out to characterize the occupational accidents involving potentially contaminated material among workers of hospital supporting services. The study reviewed records of workers involved in these accidents and attended at a specialized outpatient clinic of a large tertiary care hospital between January 1997 and October 2001. A total of 2814 workers from different professional categories were attended during this period. Of these, 147 (5.2%) belonged to the hospital supporting services and were the victims of 156 accidents, auxiliary cleaning personnel (80.2%), and over a third of the workers had not received any dose of hepatitis B vaccine (35.4%). Most accidents were due to sharp injuries (96.8%) caused by inadequately discarded hollow needles. Chemoprophylaxis for HIV was not indicated in only 23.1% of cases. We conclude that these workers are also exposed to the possibility of acquiring blood-borne pathogens and that periodical education programs are needed.

  11. A novel three-dimensional scaffold for regenerative endodontics: materials and biological characterizations.

    Science.gov (United States)

    Bottino, Marco C; Yassen, Ghaeth H; Platt, Jeffrey A; Labban, Nawaf; Windsor, L Jack; Spolnik, Kenneth J; Bressiani, Ana H A

    2015-11-01

    An electrospun nanocomposite fibrous material holds promise as a scaffold, as well as a drug-delivery device to aid in root maturogenesis and the regeneration of the pulp-dentine complex. A novel three-dimensional (3D) nanocomposite scaffold composed of polydioxanone (PDS II®) and halloysite nanotubes (HNTs) was designed and fabricated by electrospinning. Morphology, structure, mechanical properties and cell compatibility studies were carried out to evaluate the effects of HNTs incorporation (0.5-10 wt% relative to PDS w/w). Overall, a 3D porous network was seen in the different fabricated electrospun scaffolds, regardless of the HNT content. The incorporation of HNTs at 10 wt% led to a significant (p endodontics. Copyright © 2013 John Wiley & Sons, Ltd.

  12. Computer-assisted Biology Learning Materials: Designing and Developing an Interactive CD on Spermatogenesis

    Science.gov (United States)

    Haviz, M.

    2018-04-01

    The purpose of this article is to design and develop an interactive CD on spermatogenesis. This is a research and development. Procedure of development is making an outline of media program, making flowchart, making story board, gathering of materials, programming and finishing. The quantitative data obtained were analyzed by descriptive statistics. Qualitative data obtained were analyzed with Miles and Huberman techniques. The instrument used is a validation sheet. The result of CD design with a Macro flash MX program shows there are 17 slides generated. This prototype obtained a valid value after a self-review technique with many revisions, especially on sound and programming. This finding suggests that process-oriented spermatogenesis can be audio-visualized into a more comprehensive form of learning media. But this interactive CD product needs further testing to determine consistency and resistance to revisions.

  13. Protein Structure Initiative Material Repository: an open shared public resource of structural genomics plasmids for the biological community

    Science.gov (United States)

    Cormier, Catherine Y.; Mohr, Stephanie E.; Zuo, Dongmei; Hu, Yanhui; Rolfs, Andreas; Kramer, Jason; Taycher, Elena; Kelley, Fontina; Fiacco, Michael; Turnbull, Greggory; LaBaer, Joshua

    2010-01-01

    The Protein Structure Initiative Material Repository (PSI-MR; http://psimr.asu.edu) provides centralized storage and distribution for the protein expression plasmids created by PSI researchers. These plasmids are a resource that allows the research community to dissect the biological function of proteins whose structures have been identified by the PSI. The plasmid annotation, which includes the full length sequence, vector information and associated publications, is stored in a freely available, searchable database called DNASU (http://dnasu.asu.edu). Each PSI plasmid is also linked to a variety of additional resources, which facilitates cross-referencing of a particular plasmid to protein annotations and experimental data. Plasmid samples can be requested directly through the website. We have also developed a novel strategy to avoid the most common concern encountered when distributing plasmids namely, the complexity of material transfer agreement (MTA) processing and the resulting delays this causes. The Expedited Process MTA, in which we created a network of institutions that agree to the terms of transfer in advance of a material request, eliminates these delays. Our hope is that by creating a repository of expression-ready plasmids and expediting the process for receiving these plasmids, we will help accelerate the accessibility and pace of scientific discovery. PMID:19906724

  14. Determination of some trace elements in biological materials using the short living isotopes

    International Nuclear Information System (INIS)

    Taskaev, E.

    1985-01-01

    A method for determination of V, Cu, Rb, Mo and K in breast cancer tumors is described. Samples were irradiated with ICIS pneumatic irradiation system of University of London Reactor Centre for 5 min. with mixed neutron flux: 1,7.10 1 2 thermal neutrons.cm -2 .s -1 and 9.10 11 fast neutrons.cm -2 .s -1 . Wet ashing procedure of Byrne and Kosta was used for the dissolution. Consecutive separation procedures of V and Mo, Cu, Mn, K and Rb, followed by counting and activity measuring were carried out. In order to study the chemical yields for all the elements both animal and plant matrixes were used. The error of 3% ( 0.05 confidence level) for single determination of chemical yield was chosen as the highest value acceptable. The possibility of using 137-Cs tracer for K and Rb chemical yield determination was also checked. To check the whole procedure the standard reference materials SRM-1577 Bovine Liver, SRM-1571 Orchard Leaves and Bowen's Kale were analysed

  15. Measurement of spectra for intra-oral X-ray beams using biological materials as attenuator

    International Nuclear Information System (INIS)

    Zenóbio, Madelon A.F.; Nogueira-Tavares, Maria S.; Zenóbio, Elton G.; Squair, Peterson Lima; Santos, Marcus A.P.; Silva, Teógenes A. da

    2011-01-01

    In diagnostic radiology, the radiation interaction probability in matter is a strong function of the X-ray energy. The knowledge of the X-ray energy spectral distribution allows optimizing the radiographic imaging system in order to obtain high quality images with as low as reasonably achievable patient doses. In this study, transmitted X-ray spectra through dentin and enamel that are existing materials in intra-oral radiology were experimentally determined in an X-ray equipment with 40–70 kV variable range. Dentin and enamel samples with 0.4–3.8 and 0.6–2.6 mm thick were used as attenuators. X-ray transmitted spectra were measured with XR-100T model CdTe detector and half-value layers (HVL) were determined. Characteristics of both dentin and enamel transmitted spectra showed that they have differences in the penetration power in matter and in the spectrum distribution. The results will be useful for phantom developments based on dentin and enamel for image quality control in dental radiology. - Highlights: ► The X-ray energy spectral distribution, optimize the radiographic imaging system. Transmitted X-ray spectra through dentin and enamel were experimentally determined. X-ray transmitted spectra were measured (XR-100T model CdTe detector). The transmitted spectra showed differences in the penetration power and spectrum distribution. Dentin and enamel transmitted spectra will be useful for phantom developments.

  16. A review of cutting mechanics and modeling techniques for biological materials.

    Science.gov (United States)

    Takabi, Behrouz; Tai, Bruce L

    2017-07-01

    This paper presents a comprehensive survey on the modeling of tissue cutting, including both soft tissue and bone cutting processes. In order to achieve higher accuracy in tissue cutting, as a critical process in surgical operations, the meticulous modeling of such processes is important in particular for surgical tool development and analysis. This review paper is focused on the mechanical concepts and modeling techniques utilized to simulate tissue cutting such as cutting forces and chip morphology. These models are presented in two major categories, namely soft tissue cutting and bone cutting. Fracture toughness is commonly used to describe tissue cutting while Johnson-Cook material model is often adopted for bone cutting in conjunction with finite element analysis (FEA). In each section, the most recent mathematical and computational models are summarized. The differences and similarities among these models, challenges, novel techniques, and recommendations for future work are discussed along with each section. This review is aimed to provide a broad and in-depth vision of the methods suitable for tissue and bone cutting simulations. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  17. 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

  18. Use of 5-(4-dimethylaminobenzylidene)rhodanine in quantitating silver grains eluted from autoradiograms of biological material

    International Nuclear Information System (INIS)

    Ludlow, J.W.; Guikema, J.A.; Consigli, R.A.

    1986-01-01

    5-(4-Dimethylaminobenzylidene)rhodanine, a silver-specific dye, was used in a colorimetric assay to quantitate the autoradiographic deposition of silver onto X-ray film after exposure to sodium dodecyl sulfate-polyacrylamide gels of radiolabeled biological material. Silver grains were eluted from autoradiograms with 5 N potassium hydroxide, dissolved in nitric acid, and neutralized with 1 M Trizma Base. The concentration of silver was measured spectrophotometrically owing to the chelation properties of the dye. After corrections for background exposure were made, the silver contents of excised bands were then determined by comparison to a standard curve generated with silver nitrate. We have used this silver assay to quantitate the relative amount of each polypeptide band comprising the polyomavirus structural protein VP2 doublet. The method reported here has proven useful when densitometry is inconvenient (i.e., short distance between bands, irregular shape of bands, very faint bands) in addition to being inexpensive and simple to perform

  19. Microdetermination of lead, cadmium, zinc and tin in biological and related materials by atomic absorption spectrometry after mineralisation and extraction

    International Nuclear Information System (INIS)

    Boiteau, H.L.; Metayer, C.

    1978-01-01

    Two technics permitting to determine either lead, cadmium and zinc, or tin in any biological material (blood, urines, organs, alimentary products of animal or vegetable origin) are described. Every operation (mineralisation and extraction) is made in the same tube and technics, conceived in a way to simplify the manipulations and to reduce the more possible the contamination risks are suitable for determination in series. By working on trial samples near 250 mg, the lower determination limits are around 2 ppb for cadmium, 40 ppb for lead and tin and 2 ppm for zinc. The repeatability studies of different technical stages show that mineralisation and extraction only have a weak incidence on the acccuracy of the results [fr

  20. Evaluation of some procedures relevant to the determination of trace elemental components in biological materials by destructive neutron activation analysis

    International Nuclear Information System (INIS)

    Berry, D.L.

    1979-01-01

    The development of a simplified procedure for the analysis of biological materials by destructive neutron activation analysis (DNAA) is described. The sample manipulations preceding gamma ray assay were investigated as five specific stages of processing: (1) pre-irradiation treatment; (2) sample irradiation; (3) removal of the organic matrix; (4) removal of interfering radioactivities; and (5) concentration and separation of analyte activities. Each stage was evaluated with respect to susceptibility to sample contamination, loss of trace elemental components, and compatibility with other operations in the overall DNAA procedures. A complete DNAA procedure was proposed and evaluated for the analysis of standard bovine liver and blood samples. The DNAA system was effective for the determination of As, Cu, Fe, Hg, Mo, Rb, Sb, Se, and Zn without yield determinations and with a minimum turn-around time of approximately 3 days

  1. Evaluation of some procedures relevant to the determination of trace elemental components in biological materials by destructive neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Berry, D.L.

    1979-01-01

    The development of a simplified procedure for the analysis of biological materials by destructive neutron activation analysis (DNAA) is described. The sample manipulations preceding gamma ray assay were investigated as five specific stages of processing: (1) pre-irradiation treatment; (2) sample irradiation; (3) removal of the organic matrix; (4) removal of interfering radioactivities; and (5) concentration and separation of analyte activities. Each stage was evaluated with respect to susceptibility to sample contamination, loss of trace elemental components, and compatibility with other operations in the overall DNAA procedures. A complete DNAA procedure was proposed and evaluated for the analysis of standard bovine liver and blood samples. The DNAA system was effective for the determination of As, Cu, Fe, Hg, Mo, Rb, Sb, Se, and Zn without yield determinations and with a minimum turn-around time of approximately 3 days.

  2. Collaborative international research: ethical and regulatory issues pertaining to human biological materials at a South African institutional research ethics committee.

    Science.gov (United States)

    Sathar, Aslam; Dhai, Amaboo; van der Linde, Stephan

    2014-12-01

    Human Biological Materials (HBMs) are an invaluable resource in biomedical research. To determine if researchers and a Research Ethics Committee (REC) at a South African institution addressed ethical issues pertaining to HBMs in collaborative research with developed countries. Ethically approved retrospective cross-sectional descriptive audit. Of the 1305 protocols audited, 151 (11.57%) fulfilled the study's inclusion criteria. Compared to other developed countries, a majority of sponsors (90) were from the USA (p = 0.0001). The principle investigators (PIs) in all 151 protocols informed the REC of their intent to store HBMs. Only 132 protocols informed research participants (P ethical and regulatory issues pertaining to HBMs. There was a lack of congruence between the ethical guidelines of developed countries and their actions which are central to the access to HBMs in collaborative research. HBMs may be leaving South Africa without EPs and MTAs during the process of international collaborative research. © 2013 John Wiley & Sons Ltd.

  3. Determination of several trace metals in biological materials by PIXE analysis after solvent extraction and polystyrene-film collection

    International Nuclear Information System (INIS)

    Iwata, Yoshihiro; Korenaga, Tatsumi; Suzuki, Nobuo

    1991-01-01

    Traces of vanadium, manganese, iron, cobalt, nickel, copper, and zinc were quantitatively extracted with diethyldithiocarbamate (DDTC) in benzene from a digested solution of biological materials and the metal-DDTC complexes were collected into a small amount of polystyrene foam produced by lyophilization of the benzene extract after addition of polystyrene. The polystyrene foam was dissolved in benzene and spread on Mylar film. After drying, a polystyrene film containing metal-DDTC complexes was produced on Mylar film, and then the polystyrene film was peeled from the Mylar film. This film was subjected to PIXE analysis. This method was applied to NBS SRM 1572 citrus leaves and a marine macroalgal sample, and 6 trace metals were simultaneously and accurately determined. (author)

  4. Neutron activation analysis of biological materials for sub PPM amount of mercury without determining the chemical yield

    International Nuclear Information System (INIS)

    Foldzinska, A.; Dybczynski, R.

    1976-01-01

    A simple method for the determination of sub ppm amounts of mercury in various biological materials by neutron activation analysis is described. Irradiated samples were decomposed with H 2 SO 4 - fuming HNO 3 mixture and mercury selectively isolated by ion exchange chromatography using Dowex 50X2(H + ) and Dowex 1X4(Br - ) columns in HBr medium. Finally the activity of 197 Hg fixed on an anion exchange resin was measured either with a Ge(Li) or a NaI (Tl) detector. Both the high radiochemical purity of mercury and the practically quantitative recovery were achieved thus eliminating the necessity of determining the chemical yield. The method was used for the determination of mercury in flour, milk, butter, margarine, fish, etc. Total time of analysis (including counting) amounted to 6-7 hrs and several samples could be simultaneously analysed by one technician. (T.G.)

  5. Standardization of digestion procedure for the determination of heavy metals in biological materials by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Khalid, N.; Chaudhri, S.A.

    1999-01-01

    Proper decomposition of the sample is one of the basic requirements of the atomic absorption spectroscopic analysis. In the present studies, heavy metals (Cu, Fe, Mn and Zn) were determined in biological samples by designating them in a mixture of nitric acid and perchloric acid. The quantification was made with atomic absorption spectrometry using an air-acetylene flame. The reliability of the procedure used was checked by analysing standard reference materials from NBS and IAEA, such as Rice flour (NBS-SRM-1568), Horse Kidney (IAEA H-8), Mixed Human diet(IAEA H-9), Copepod (IAEA MA-A-1) and fish flesh (IAEA MA-A-2) under identical conditions. A good agreement was observed between determined and the certified values reported by NBS and IAEA. (author)

  6. Ultrahigh frequency tunability of aperture-coupled microstrip antenna via electric-field tunable BST

    Science.gov (United States)

    Du, Hong-Lei; Xue, Qian; Gao, Xiao-Yang; Yao, Feng-Rui; Lu, Shi-Yang; Wang, Ye-Long; Liu, Chun-Heng; Zhang, Yong-Cheng; Lü, Yue-Guang; Li, Shan-Dong

    2015-12-01

    A composite ceramic with nominal composition of 45.0 wt%(Ba0.5Sr0.5)TiO3-55.0 wt%MgO (acronym is BST-MgO) is sintered for fabricating a frequency reconfigurable aperture-coupled microstrip antenna. The calcined BST-MgO composite ceramic exhibits good microwave dielectric properties at X-band with appropriate dielectric constant ɛr around 85, lower dielectric loss tan δ about 0.01, and higher permittivity tunability 14.8% at 8.33 kV/cm. An ultrahigh E-field tunability of working frequency up to 11.0% (i.e., from 9.1 GHz to 10.1 GHz with a large frequency shift of 1000 MHz) at a DC bias field from 0 to 8.33 kV/cm and a considerably large center gain over 7.5 dB are obtained in the designed frequency reconfigurable microstrip antenna. These results demonstrate that BST materials are promising for the frequency reconfigurable antenna. Project supported by the National Natural Science Foundation of China (Grant No. 11074040) and the Key Project of Shandong Provincial Department of Science and Technology, China (Grant No. ZR2012FZ006).

  7. [Accidents with biological material in health care workers in 2 primary health care areas (1990-1999)].

    Science.gov (United States)

    Hernández Navarrete, M J; Montes Villameriel, F J; Solano Bernad, V M; Sánchez Matienzo, D; del Val García, J L; Gil Montalbán, E; Arribas Llorente, J L

    2001-09-15

    To find out the exposures with biological material in health care workers in primary health care, registered in the biological accidents database from Preventive Medicine Service in Miguel Servet Universitary Hospital of Zaragoza. Descriptive study of a retrospective cohort. SITE: Primary health care, Areas II and V of Zaragoza.Participants. Workers in this areas, distributed by: physician, nursing staff, auxiliary, orderly, housekeeping staff, others. Data of: workers, accident, serologic source, worker protection and vaccinal status of hepatitis B. The incidence of accidents was 26 (period 1997-1999). Most proportion of accidents were declared by nursing (78%). The highest occupational incidence was in auxiliary (63 ). In 90,1% of the cases, the accident was needlestick injury. The source was known in 67,7% of cases. The accidents occurred in hands in 96,8% of cases, and only one third of workers carried gloves. Results obtained are similar with previous studies about this event. We must insist on the need to declare these accidents, providing more information and accessibility for the declaration to worker. Moreover, we must insist on the correct application in the health care field of the standard precautions, because almost 50% of accidents are evitable, and to increase hepatitis B vaccination covertures.

  8. [Accidents with exposure to biological material contaminated with HIV in workers at a third level hospital in Madrid].

    Science.gov (United States)

    García de Codes Ilario, Aurelia; de Juanes Pardo, José Ramón; Arrazola Martínez, M del Pilar; Jaén Herreros, Felisa; Sanz Gallardo, M Inmaculada; Lago López, Emilia

    2004-01-01

    Human Immunodeficiency Virus (HIV) is an occupational hazard among healthcare professionals accidentally contaminated with HIV-positive blood. This study is aimed at describing the characteristics of the accidents involving blood of HIV-positive patients recorded over a sixteen-year period at a general hospital. Epidemiological study of the accidents reported in 2001 involving biological material from an HIV-positive source by the healthcare personnel of a general hospital throughout the 1986-2001 period entailing the presence of biological material from HIV-positive serology individuals. Individual, time and place-related variables, in addition to the initial serologies and those throughout the protocolized follow-up were studied for those individuals involved in these accidents. A total 550 accidents entailing an HIV-positive source were reported. The average number of accidents was 34.4/year. The accidental exposure rate for the period under study was 7.5/1000 workers/year. The professional group showing the highest accident rate was the nursing staff (54.4%). Percutaneous injuries were the most frequent (80.2%). The mean exposure rate was 2.6/100 beds/year. The anatomical areas involved to the greatest degree were the fingers (75.6%). A total 53.4% of those injured completed the serological follow-up without having shown any seroconversion. Throughout the sixteen-year period under study, the annual incidence of accidents involving an HIV-positive source increased from the 27 accidents reported in 1986 to the 60 accidents reported in 1990, there having been a downward trend as of that point in time, to the point of 12 accidents having been recorded in 2001.

  9. Tunable photonic bandgap fiber based devices for optical networks

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Scolari, Lara; Rottwitt, Karsten

    2005-01-01

    In future all optical networks one of the enabling technologies is tunable elements including reconfigurable routers, switches etc. Thus, the development of a technology platform that allows construction of tuning components is critical. Lately, microstructured optical fibers, filled with liquid......, for example a liquid crystal that changes optical properties when subjected to, for example, an optical or an electrical field. The utilization of these two basic properties allows design of tunable optical devices for optical networks. In this work, we focus on applications of such devices and discuss recent...... crystals, have proven to be a candidate for such a platform. Microstructured optical fibers offer unique wave-guiding properties that are strongly related to the design of the air holes in the cladding of the fiber. These wave-guiding properties may be altered by filling the air holes with a material...

  10. Tunable synthesis of copper nanotubes

    International Nuclear Information System (INIS)

    Kaniukov, E; Yakimchuk, D; Kozlovsky, A; Shlimas, D; Zdorovets, M; Kadyrzhanov, K

    2016-01-01

    Simple method of tunable synthesis of copper nanotubes based on template synthesis was developed. A comprehensive study of the structural, morphological and electrical characteristics of the obtained nanostructures was carried out. Characterization of structural features was made by methods of scanning electron microscopy, energy dispersive spectroscopy and X-ray diffractometry analysis. Evaluation of wall thickness is made by methods of gas permeability. Electrical conductivity of nanotubes was define in the study of their current-voltage characteristics. The possibility to control of copper nanotubes physical properties by variation of the deposition parameters was shown. (paper)

  11. New Methods of Simulation of Mn(II) EPR Spectra: Single Crystals, Polycrystalline and Amorphous (Biological) Materials

    Science.gov (United States)

    Misra, Sushil K.

    Biological systems exhibit properties of amorphous materials. The Mn(II) ion in amorphous materials is characterized by distributions of spin-Hamiltonian parameters around mean values. It has a certain advantage over other ions, being one of the most abundant elements on the earth. The extent to which living organisms utilize manganese varies from one organism to the other. There is a fairly high concentration of the Mn(II) ion in green plants, which use it in the O2 evolution reaction of photosynthesis (Sauer, 1980). Structure-reactivity relationships in Mn(II)-O2 complexes are given in a review article by Coleman and Taylor (1980). Manganese is a trace requirement in animal nutrition; highly elevated levels of manganese in the diet can be toxic, probably because of an interference with iron homeostasis (Underwood, 1971). On the other hand, animals raised with a dietary deficiency of manganese exhibit severe abnormalities in connective tissue; these problems have been attributed to the obligatory role of Mn(II) in mucopolysaccharide metabolism (Leach, 1971). Mn(II) has been detected unequivocally in living organisms.

  12. Biological regeneration of carrier material for the adsorption of halogen hydrocarbons in plants for cleaning up contaminated groundwater. Final report

    International Nuclear Information System (INIS)

    Ressel, K.

    1993-06-01

    Halogen hydrocarbons and above all chlorinated hydrocarbons are widespread harmful substances in soils and in groundwater. When cleaning up groundwater contamination, the contaminants are brought into the gas phase by strip processes. From the gas phase, the contaminants can be adsorbed on different carrier materials, mostly active carbon. One was searching for ways to regenerate this adsorption material. The mixed culture from a sea sediment most suitable for the decomposition of chlorinated hydrocarbons was optimized regarding its decomposition performance and was later used on the technical scale. In the decomposition experiments on the large technical scale, the cultures were lodged on filling bodies which has a much higher amount of gaps. In this case, an optimum supply of the micro-organisms with oxygen and methane is guaranteed, which is used as co-substrate. No intermediate product was found in a gas chromatography examination. The biologically occupied stage is situated between a desorption column and the active carbon filters, and reduces the load of harmful substances which can no longer be brought into the gas phase by stripping out. This has the advantage that it can be integrated in existing plants and can be adapted to any case of contamination by lodging adapted micro-organisms on it. The basis for each application must be separately researched. (orig.) [de

  13. Accurate determination of trace amounts of lanthanum, yttrium and all stable lanthanides in biological materials by Ion Chromatography

    International Nuclear Information System (INIS)

    Dybczynski, R.S.; Kulisa, K.; Danko, B.; Samczynski, Z.

    2007-01-01

    The analytical procedure for the isolation and preconcentration of La, Y and the lanthanides from biological materials and their determination by ion chromatography (IC) with the use of Dionex Ion Pac CS3 + CG3 column (sulfonic acid type), α-hydroxyisobutyric acid (α-HIBA) as an eluent, and PAR or Arsenazo III as color forming reagents, was elaborated. The scheme originally devised for NAA, involving microwave assisted digestion and multi step separation employing ion exchange and extraction chromatography columns was used to selectively recover REE fraction (without scandium) with 100% yield. The REE fraction was analyzed by IC at 25 and 70 o C. The run at 70 o C enabled resolution of Y and Dy peaks and as a result made possible quantitative determination of La, Y, and all lanthanides. Investigation on the mechanism of band spreading revealed that longitudinal diffusion in the stationary phase considerably contributed to the total plate height. Surprisingly, the plate height (H) calculated from Y peak was distinctly lower than H values of the adjacent lanthanides. The method was validated by analyzing several certified reference materials (CRMs). (authors)

  14. Physical and biological properties of a novel anti-adhesion material made of thermally cross-linked gelatin film: Investigation of the usefulness as anti-adhesion material.

    Science.gov (United States)

    Horii, Tsunehito; Tsujimoto, Hiroyuki; Miyamoto, Hiroe; Yamanaka, Koki; Tanaka, Shota; Torii, Hiroko; Ozamoto, Yuki; Takamori, Hideki; Nakamachi, Eiji; Ikada, Yoshito; Hagiwara, Akeo

    2018-02-01

    To create more useful, effective and safer anti-adhesion materials, we developed a thermally cross-linked gelatin film. In this study, we examined the physical properties of the film such as the physical strength and the adhesiveness to reveal the handling properties and biological properties, such as the anti-adhesion effect, the influence on cell proliferation, and the cytotoxicity to reveal the anti-adhesion mechanism, especially in comparison with the conventional hyaluronic acid and carboxymethylcellulose film (the conventional film). A tensile test under dry and wet conditions and shearing stress test showed that the gelatin film has significant higher maximum tensile stress and fracture strain than the conventional film. In the study using a rat model of cecum adhesion, the anti-adhesion effect of the gelatin film was significantly superior to that of the conventional film. In the cell proliferation test, the number of fibroblast cells on the gelatin film increased at each time point, while no cell proliferation was observed on the conventional film. Furthermore, in the cytotoxicity test using a colony assay and Live/Dead assay, the extract of the gelatin film had no cytotoxicity, while the extract of the conventional film had cytotoxicity considerably. These results suggest that the gelatin film provides better handling than the conventional film, due to better physical strength and ductility of the film. In addition, the gelatin film has a significantly greater anti-adhesion effect than the conventional film without any cytotoxicity. Therefore, the gelatin film is quite favorable as an anti-adhesion material. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 689-696, 2018. © 2017 Wiley Periodicals, Inc.

  15. Influence of Pichia pastoris cellular material on polymerase chain reaction performance as a synthetic biology standard for genome monitoring.

    Science.gov (United States)

    Templar, Alexander; Woodhouse, Stefan; Keshavarz-Moore, Eli; Nesbeth, Darren N

    2016-08-01

    Advances in synthetic genomics are now well underway in yeasts due to the low cost of synthetic DNA. These new capabilities also bring greater need for quantitating the presence, loss and rearrangement of loci within synthetic yeast genomes. Methods for achieving this will ideally; i) be robust to industrial settings, ii) adhere to a global standard and iii) be sufficiently rapid to enable at-line monitoring during cell growth. The methylotrophic yeast Pichia pastoris (P. pastoris) is increasingly used for industrial production of biotherapeutic proteins so we sought to answer the following questions for this particular yeast species. Is time-consuming DNA purification necessary to obtain accurate end-point polymerase chain reaction (e-pPCR) and quantitative PCR (qPCR) data? Can the novel linear regression of efficiency qPCR method (LRE qPCR), which has properties desirable in a synthetic biology standard, match the accuracy of conventional qPCR? Does cell cultivation scale influence PCR performance? To answer these questions we performed e-pPCR and qPCR in the presence and absence of cellular material disrupted by a mild 30s sonication procedure. The e-pPCR limit of detection (LOD) for a genomic target locus was 50pg (4.91×10(3) copies) of purified genomic DNA (gDNA) but the presence of cellular material reduced this sensitivity sixfold to 300pg gDNA (2.95×10(4) copies). LRE qPCR matched the accuracy of a conventional standard curve qPCR method. The presence of material from bioreactor cultivation of up to OD600=80 did not significantly compromise the accuracy of LRE qPCR. We conclude that a simple and rapid cell disruption step is sufficient to render P. pastoris samples of up to OD600=80 amenable to analysis using LRE qPCR which we propose as a synthetic biology standard. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Inalienably Yours? The new case for an inalienable property right in human biological material: Empowerment of sample donors or a recipe for a tragic Anti-Commons?

    Directory of Open Access Journals (Sweden)

    Jasper A. Bovenberg

    2004-12-01

    Full Text Available Modern biomedical research into the genetic component of common diseases calls for broad access to existing and novel collections of samples of human biological material, aka Biobanks. Groups of donors of these samples, however, increasingly claim a property right in their samples. They perceive the recognition of a personal property right in their biological material as the best means to serve two goals: to secure ongoing control over their samples after donation and to underpin their claim for a share in the proceeds that the research on their samples may yield. Given the objective of ensuring ongoing control, this property right is claimed to be inalienable. Recognition of a personal property right in one’s biological material is problematic, especially where the requirement of inalienability seems at odds with the claim for a share of the profits. Yet, property rights in human biological material may be justified in a certain context, e.g. to enable subsets of patients to negotiate the terms and conditions of the research into their specific disorders. Biobanks, however, contain so many samples, which can be used for so many research purposes, that the unrestricted exercise of personal property rights by the sample donors will lead to a proliferation of rights. This proliferation is likely to deter or slow down both the creation of de novo Biobanks and the use of existing sample collections. Thus, recognising inalienable property rights in human biological material may lead to suboptimal use of these resources and create a classic ‘anticommons property’ scenario. It would also undermine the current trend to simplify existing informed consent requirements which aims to facilitate broad and previously unanticipated research on de novo and existing Biobanks. In addition, the tradition of altruistic participation in research and the notion that large-scale collections of human biological material are global public goods are arguments against

  17. Stretchable Random Lasers with Tunable Coherent Loops.

    Science.gov (United States)

    Sun, Tzu-Min; Wang, Cih-Su; Liao, Chi-Shiun; Lin, Shih-Yao; Perumal, Packiyaraj; Chiang, Chia-Wei; Chen, Yang-Fang

    2015-12-22

    Stretchability represents a key feature for the emerging world of realistic applications in areas, including wearable gadgets, health monitors, and robotic skins. Many optical and electronic technologies that can respond to large strain deformations have been developed. Laser plays a very important role in our daily life since it was discovered, which is highly desirable for the development of stretchable devices. Herein, stretchable random lasers with tunable coherent loops are designed, fabricated, and demonstrated. To illustrate our working principle, the stretchable random laser is made possible by transferring unique ZnO nanobrushes on top of polydimethylsiloxane (PDMS) elastomer substrate. Apart from the traditional gain material of ZnO nanorods, ZnO nanobrushes were used as optical gain materials so they can serve as scattering centers and provide the Fabry-Perot cavity to enhance laser action. The stretchable PDMS substrate gives the degree of freedom to mechanically tune the coherent loops of the random laser action by changing the density of ZnO nanobrushes. It is found that the number of laser modes increases with increasing external strain applied on the PDMS substrate due to the enhanced possibility for the formation of coherent loops. The device can be stretched by up to 30% strain and subjected to more than 100 cycles without loss in laser action. The result shows a major advance for the further development of man-made smart stretchable devices.

  18. Plasmonic spectral tunability of conductive ternary nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Kassavetis, S.; Patsalas, P., E-mail: ppats@physics.auth.gr [Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Bellas, D. V.; Lidorikis, E. [Department of Materials Science and Engineering, University of Ioannina, GR-45110 Ioannina (Greece); Abadias, G. [Institut Pprime, Département Physique et Mécanique des Matériaux, Université de Poitiers-CNRS-ENSMA, 86962 Chasseneuil-Futuroscope (France)

    2016-06-27

    Conductive binary transition metal nitrides, such as TiN and ZrN, have emerged as a category of promising alternative plasmonic materials. In this work, we show that ternary transition metal nitrides such as Ti{sub x}Ta{sub 1−x}N, Ti{sub x}Zr{sub 1−x}N, Ti{sub x}Al{sub 1−x}N, and Zr{sub x}Ta{sub 1−x}N share the important plasmonic features with their binary counterparts, while having the additional asset of the exceptional spectral tunability in the entire visible (400–700 nm) and UVA (315–400 nm) spectral ranges depending on their net valence electrons. In particular, we demonstrate that such ternary nitrides can exhibit maximum field enhancement factors comparable with gold in the aforementioned broadband range. We also critically evaluate the structural features that affect the quality factor of the plasmon resonance and we provide rules of thumb for the selection and growth of materials for nitride plasmonics.

  19. Investigations on construction material and construction concepts in order to obtain dose-reducing effects in the dismantling of the biological shield of a 1300 MWe-PWR

    International Nuclear Information System (INIS)

    Bittner, A.; Jungwirth, D.; Knell, M.; Schnitzler, L.

    1984-04-01

    Numerical values of neutron fluxes, activations, dose rates etc. as a function of characteristic values of materials required for optimization purposes to reduce the radiation effect of the biological shield of a PWR are not available. Design concepts are presented for biological shields of PWRs made of concrete with respect to both the most suitable application of materials and the design principles aiming at reduced radiation exposure as compared to present designs during entering, waste disposal and ultimate storage. To evaluate the present-state design the above values have been calculated. Suggested alternative designs are biological shields with selective material application, built from precast elements with or without boron carbide layer arranged in front of it. (orig./HP) [de

  20. Colloidal Photonic Crystals Containing Silver Nanoparticles with Tunable Structural Colors

    Directory of Open Access Journals (Sweden)

    Chun-Feng Lai

    2016-05-01

    Full Text Available Polystyrene (PS colloidal photonic crystals (CPhCs containing silver nanoparticles (AgNPs present tunable structural colors. PS CPhC color films containing a high concentration of AgNPs were prepared using self-assembly process through gravitational sedimentation method. High-concentration AgNPs were deposited on the bottom of the substrate and acted as black materials to absorb background and scattering light. Brilliant structural colors were enhanced because of the absorption of incoherent scattering light, and color saturation was increased by the distribution AgNPs on the PS CPhC surfaces. The vivid iridescent structural colors of AgNPs/PS hybrid CPhC films were based on Bragg diffraction and backward scattering absorption using AgNPs. The photonic stop band of PS CPhCs and AgNPs/PS hybrid CPhCs were measured by UV–visible reflection spectrometry and calculated based on the Bragg–Snell law. In addition, the tunable structural colors of AgNPs/PS hybrid CPhC films were evaluated using color measurements according to the Commission International d’Eclairage standard colorimetric system. This paper presents a simple and inexpensive method to produce tunable structural colors for numerous applications, such as textile fabrics, bionic colors, catalysis, and paints.

  1. A rapid neutron activation method for the determination of traces of mercury. The mercury content of biological material of differing geographical and chronological origin

    International Nuclear Information System (INIS)

    Rohde, H.

    1975-08-01

    A rapid method based on activation analysis has been developed for the determination of mercury in biological material. The method employs the delayed gamma rays as prompt gamma rays have been shown to display insufficient sensitivity. The mercury content of 182 fish derived from the waters of the region of South Western Germany has been determined. Relatively high concentrations (> 1 ppm) have been measured in the muscle of Rhine fish. Similar mercury contents have been observed in aged biological material (birds feathers and human hair) and contemporary living organisms. (orig.) [de

  2. MAK and BAT values list 2017. Maximum permissible concentrations at the place of work and biological tolerance values for working materials; MAK- und BAT-Werte-Liste 2017. Maximale Arbeitsplatzkonzentrationen und Biologische Arbeitsstofftoleranzwerte

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2017-08-01

    The MAK and BAT values list 2017 includes the maximum permissible concentrations at the place of work and biological tolerance values for working materials. The following working materials are covered: carcinogenic working materials, sensitizing materials and aerosols. The report discusses the restriction of exposure peaks, skin resorption, MAK (maximum working place concentration) values during pregnancy, germ cell mutagens and specific working materials. Importance and application of BAT (biological working material tolerance) values, list of materials, carcinogens, biological guide values and reference values are also included.

  3. Coumarin-BODIPY hybrids by heteroatom linkage: versatile, tunable and photostable dye lasers for UV irradiation.

    Science.gov (United States)

    Esnal, I; Duran-Sampedro, G; Agarrabeitia, A R; Bañuelos, J; García-Moreno, I; Macías, M A; Peña-Cabrera, E; López-Arbeloa, I; de la Moya, S; Ortiz, M J

    2015-03-28

    Linking amino and hydroxycoumarins to BODIPYs through the amino or hydroxyl group lets the easy construction of unprecedented photostable coumarin-BODIPY hybrids with broadened and enhanced absorption in the UV spectral region, and outstanding wavelength-tunable laser action within the green-to-red spectral region (∼520-680 nm). These laser dyes allow the generation of a valuable tunable UV (∼260-350 nm) laser source by frequency doubling, which is essential to study accurately the photochemistry of biological molecules under solar irradiation. The tunability is achieved by selecting the substitution pattern of the hybrid. Key factors are the linking heteroatom (nitrogen vs. oxygen), the number of coumarin units joined to the BODIPY framework and the involved linking positions.

  4. [Occupational injury incidence due to biological material in a tertiary referral public hospital in Santa Fe province].

    Science.gov (United States)

    Huanca, Romina; Perretta, Luis; Lebensohn, Natalia; Di Paolo, Oscar; Pires, Miryam; Quaglia, Nora Beatriz

    2016-01-01

    Occupational accidents due to biological materials cause significant harm to workers and institutions. To estimate the risk of accidents in doctors and nurses at the Hospital Provincial del Centenario (HPC) and particularly in Emergency Medical Service (EMS) between 2009 and 2013. retrospective cohort study from the survey information of injuries by accidents with biohazard in doctors and nurses workers from HPC. medical workers reported 45.7% (95% CI 37.2 to 54.3%) of accidents and nurses 38.4% (from 30.3 to 47.1%). The incidence rate ratio (IRR) (doctors / nurses) (2009-2013) = 0.953 (0.661-1.373). EMS workers ages and seniority were significantly lower than those of other care areas taken together. Reports of accidents from the EMS were 34.1% (95% CI: 26.2 to 42.6%) of the total. EMS workers had age and seniority average significantly less than workers in other services. In EMS, the IRR (doctors / nurses) (2009-2013) = 6.337 (2.264 -17.733). SGM medical workers ages and seniority were significantly lower than those of nurses working in this service. The EMS was particularly vulnerable to occupational injuries, medical workers have a higher risk of accidents compared to nursing workers. The younger age and lower seniority of medical workers could be related at least partly to these findings.

  5. Separation procedure for the determination of Ag, Cd, Hg and Zn in biological material by radiochemical neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Haas, H F; Krivan, V

    1986-05-01

    A simple separation procedure for the determination of Ag, Au, Cd, Hg and Zn in biological material by radiochemical neutron activation analysis was developed. It enables the separation of the indicator radionuclides sup(110m)Ag, /sup 198/Au, /sup 115/Cd, /sup 203/Hg and /sup 65/Zn in a group with yields >99% and is well suited for the separation of /sup 203/Hg from /sup 75/Se and /sup 65/Zn from /sup 46/Sc. The separation of these radionuclides is often necessary because of the occurrence of instrumental interferences in the instrumental neutron activation analysis. Simultaneously, the limits of detection for Ag, Au and Cd can significantly be improved. The method is based on the decomposition of the sample in the mixture of HNO/sub 3//HCl/H/sub 2/O/sub 2/ and on the separation of Ag, Au, Cd, Hg and Zn on Dowex 1X8 from a sample solution being 1.5 M with HCl. The applicability of this method is demonstrated by the analysis of lichens and several kinds of fungi. For the experimental conditions used, the limits of detection are of the order of magnitude of 10 ng/g.

  6. Electronically tunable RC sinusoidal oscillators

    International Nuclear Information System (INIS)

    Florescu, Valeriu

    2008-01-01

    This paper presents two types of active configurations for realizing electronically tunable RC sinusoidal oscillators. The type-1 network employs two grounded scaled resistances KR 1 and KR 2 , where K is scaling factor. The frequency of oscillation W 0 is controlled conveniently by adjusting K, since W 0 appears in the form W 0 =1/K √ R 1 C 1 R 2 C 2 . For realizing the scaled resistances, an active configuration is proposed, which realizes KR 1 =R 1 /(1+f(V B )), where f(V B ) denotes a function of a controlling voltage V B . Thus the frequency tuning can be effected by controlling a voltage V B . The type-2 oscillator uses two periodically switched conductances. It is shown that the tuning of oscillation frequency can be done by varying the pulse width-to-period ratio (t/T) of the periodically switched conductances. (author)

  7. Restricted access magnetic materials prepared by dual surface modification for selective extraction of therapeutic drugs from biological fluids

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yu; Wang Yuxia; Chen Lei [School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072 (China); Wan Qianhong, E-mail: qhwan@tju.edu.cn [School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072 (China)

    2012-02-15

    Magnetic porous particles with dual functionality have been prepared by a two-step procedure and evaluated as novel restricted access materials for extraction of therapeutic agents from biological fluids. The magnetic silica particles served as scaffolds were first modified with diol groups, which were then converted to octadecyl esters through reaction with stearoyl chloride. In the second step, the octadecyl esters on the exterior surface were hydrolyzed by the action of lipase to yield magnetic particles with hydrophobic reversed-phase ligands on the inner surface and biocompatible diol groups on the outer surface. The restricted access behavior of the resulting materials was confirmed by differential binding of small molecules such as methotrexate (MTX), leucovorin (LV) and folic acid (FA) relative to bovine serum albumin. While MTX, LV and FA were all bound to the magnetic particles with high affinity, the adsorption of the protein was markedly reduced due to size exclusion effect. The utility of the magnetic particles for sample preparation was tested in solid-phase extraction of MTX, LV and FA from spiked human serum and the effects of the SPE conditions on the recovery of the analytes were systematically studied. Moreover, the magnetic particle-based sample preparation procedure coupled with reversed-phase liquid chromatography analysis was validated in terms of specificity, linearity and reproducibility. The method was shown to be free from interference of endogenous compounds and linear over the concentration range of 0.5-10 {mu}g/mL for the three drugs studied. The limits of detection for the three drugs in serum were in the range of 0.160-0.302 {mu}g/mL. Reproducibility expressed as the RSD of the recovery for ten replicated extractions at three different concentrations was found to be less than 8.93%. With a unique combination of surface functionality with magnetic cores, the restricted access magnetic particles may be adapted in automated and high

  8. Restricted access magnetic materials prepared by dual surface modification for selective extraction of therapeutic drugs from biological fluids

    International Nuclear Information System (INIS)

    Wang Yu; Wang Yuxia; Chen Lei; Wan Qianhong

    2012-01-01

    Magnetic porous particles with dual functionality have been prepared by a two-step procedure and evaluated as novel restricted access materials for extraction of therapeutic agents from biological fluids. The magnetic silica particles served as scaffolds were first modified with diol groups, which were then converted to octadecyl esters through reaction with stearoyl chloride. In the second step, the octadecyl esters on the exterior surface were hydrolyzed by the action of lipase to yield magnetic particles with hydrophobic reversed-phase ligands on the inner surface and biocompatible diol groups on the outer surface. The restricted access behavior of the resulting materials was confirmed by differential binding of small molecules such as methotrexate (MTX), leucovorin (LV) and folic acid (FA) relative to bovine serum albumin. While MTX, LV and FA were all bound to the magnetic particles with high affinity, the adsorption of the protein was markedly reduced due to size exclusion effect. The utility of the magnetic particles for sample preparation was tested in solid-phase extraction of MTX, LV and FA from spiked human serum and the effects of the SPE conditions on the recovery of the analytes were systematically studied. Moreover, the magnetic particle-based sample preparation procedure coupled with reversed-phase liquid chromatography analysis was validated in terms of specificity, linearity and reproducibility. The method was shown to be free from interference of endogenous compounds and linear over the concentration range of 0.5-10 μg/mL for the three drugs studied. The limits of detection for the three drugs in serum were in the range of 0.160-0.302 μg/mL. Reproducibility expressed as the RSD of the recovery for ten replicated extractions at three different concentrations was found to be less than 8.93%. With a unique combination of surface functionality with magnetic cores, the restricted access magnetic particles may be adapted in automated and high

  9. Tunable emergent heterostructures in a prototypical correlated metal

    Science.gov (United States)

    Fobes, D. M.; Zhang, S.; Lin, S.-Z.; Das, Pinaki; Ghimire, N. J.; Bauer, E. D.; Thompson, J. D.; Harriger, L. W.; Ehlers, G.; Podlesnyak, A.; Bewley, R. I.; Sazonov, A.; Hutanu, V.; Ronning, F.; Batista, C. D.; Janoschek, M.

    2018-05-01

    At the interface between two distinct materials, desirable properties, such as superconductivity, can be greatly enhanced1, or entirely new functionalities may emerge2. Similar to in artificially engineered heterostructures, clean functional interfaces alternatively exist in electronically textured bulk materials. Electronic textures emerge spontaneously due to competing atomic-scale interactions3, the control of which would enable a top-down approach for designing tunable intrinsic heterostructures. This is particularly attractive for correlated electron materials, where spontaneous heterostructures strongly affect the interplay between charge and spin degrees of freedom4. Here we report high-resolution neutron spectroscopy on the prototypical strongly correlated metal CeRhIn5, revealing competition between magnetic frustration and easy-axis anisotropy—a well-established mechanism for generating spontaneous superstructures5. Because the observed easy-axis anisotropy is field-induced and anomalously large, it can be controlled efficiently with small magnetic fields. The resulting field-controlled magnetic superstructure is closely tied to the formation of superconducting6 and electronic nematic textures7 in CeRhIn5, suggesting that in situ tunable heterostructures can be realized in correlated electron materials.

  10. Experimental demonstration of water based tunable metasurface

    DEFF Research Database (Denmark)

    Odit, Mikhail; Kapitanova, Polina; Andryieuski, Andrei

    2016-01-01

    A simple dynamically tunable metasurface (two-dimensional metamaterial) operating at microwave frequencies is developed and experimentally investigated. Conceptually, the simplicity of the approach is granted by reconfigurable properties of unit cells partially filled with distilled water...

  11. 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.

  12. The Development of Biology Teaching Material Based on the Local Wisdom of Timorese to Improve Students Knowledge and Attitude of Environment in Caring the Preservation of Environment

    Science.gov (United States)

    Ardan, Andam S.

    2016-01-01

    The purposes of this study were (1) to describe the biology learning such as lesson plans, teaching materials, media and worksheets for the tenth grade of High School on the topic of Biodiversity and Basic Classification, Ecosystems and Environment Issues based on local wisdom of Timorese; (2) to analyze the improvement of the environmental…

  13. Creating biological nanomaterials using synthetic biology

    International Nuclear Information System (INIS)

    Rice, MaryJoe K; Ruder, Warren C

    2014-01-01

    Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems. (review)

  14. Creating biological nanomaterials using synthetic biology.

    Science.gov (United States)

    Rice, MaryJoe K; Ruder, Warren C

    2014-02-01

    Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems.

  15. Electrically Tunable Plasmonic Resonances with Graphene

    DEFF Research Database (Denmark)

    Emani, Naresh K.; Chung, Ting-Fung; Ni, Xingjie

    2012-01-01

    Real time switching of a plasmonic resonance may find numerous applications in subwavelength optoelectronics, spectroscopy and sensing. We take advantage of electrically tunable interband transitions in graphene to control the strength of the plasmonic resonance.......Real time switching of a plasmonic resonance may find numerous applications in subwavelength optoelectronics, spectroscopy and sensing. We take advantage of electrically tunable interband transitions in graphene to control the strength of the plasmonic resonance....

  16. Tunable Beam Diffraction in Infiltrated Microstructured Fibers

    DEFF Research Database (Denmark)

    Rosberg, Christian Romer; Bennet, Francis H.; Neshev, Dragomir N.

    We experimentally study beam propagation in two dimensional photonic lattices in microstructured optical fibers infiltrated with high index liquids. We demonstrate strongly tunable beam diffraction by dynamically varying the coupling between individual lattice sites.......We experimentally study beam propagation in two dimensional photonic lattices in microstructured optical fibers infiltrated with high index liquids. We demonstrate strongly tunable beam diffraction by dynamically varying the coupling between individual lattice sites....

  17. Tunable intraparticle frameworks for creating complex heterostructured nanoparticle libraries

    Science.gov (United States)

    Fenton, Julie L.; Steimle, Benjamin C.; Schaak, Raymond E.

    2018-05-01

    Complex heterostructured nanoparticles with precisely defined materials and interfaces are important for many applications. However, rationally incorporating such features into nanoparticles with rigorous morphology control remains a synthetic bottleneck. We define a modular divergent synthesis strategy that progressively transforms simple nanoparticle synthons into increasingly sophisticated products. We introduce a series of tunable interfaces into zero-, one-, and two-dimensional copper sulfide nanoparticles using cation exchange reactions. Subsequent manipulation of these intraparticle frameworks yielded a library of 47 distinct heterostructured metal sulfide derivatives, including particles that contain asymmetric, patchy, porous, and sculpted nanoarchitectures. This generalizable mix-and-match strategy provides predictable retrosynthetic pathways to complex nanoparticle features that are otherwise inaccessible.

  18. Mid-Infrared Continuously Tunable Single Mode VECSEL

    Science.gov (United States)

    Khiar, A.; Rahim, M.; Felder, F.; Fill, M.; Zogg, H.

    2011-12-01

    Tunable mid-infrared vertical external cavity surface emitting lasers were developed for the wavelength range around 3.8-3.9 μm and 3.2-3.3 μm, respectively. The devices are based on lead salt materials epitaxially grown by MBE on a Si substrate. The active part consists of PbSe QW in a PbSrSe host layer. Both devices are operated around -20 °C and have output power of several 10 mW. By changing the cavity length, a single mode hop free tuning range up to 80 cm-1 is achieved.

  19. Materialism.

    Science.gov (United States)

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  20. Restricted access magnetic materials prepared by dual surface modification for selective extraction of therapeutic drugs from biological fluids

    Science.gov (United States)

    Wang, Yu; Wang, Yuxia; Chen, Lei; Wan, Qian-Hong

    2012-02-01

    Magnetic porous particles with dual functionality have been prepared by a two-step procedure and evaluated as novel restricted access materials for extraction of therapeutic agents from biological fluids. The magnetic silica particles served as scaffolds were first modified with diol groups, which were then converted to octadecyl esters through reaction with stearoyl chloride. In the second step, the octadecyl esters on the exterior surface were hydrolyzed by the action of lipase to yield magnetic particles with hydrophobic reversed-phase ligands on the inner surface and biocompatible diol groups on the outer surface. The restricted access behavior of the resulting materials was confirmed by differential binding of small molecules such as methotrexate (MTX), leucovorin (LV) and folic acid (FA) relative to bovine serum albumin. While MTX, LV and FA were all bound to the magnetic particles with high affinity, the adsorption of the protein was markedly reduced due to size exclusion effect. The utility of the magnetic particles for sample preparation was tested in solid-phase extraction of MTX, LV and FA from spiked human serum and the effects of the SPE conditions on the recovery of the analytes were systematically studied. Moreover, the magnetic particle-based sample preparation procedure coupled with reversed-phase liquid chromatography analysis was validated in terms of specificity, linearity and reproducibility. The method was shown to be free from interference of endogenous compounds and linear over the concentration range of 0.5-10 μg/mL for the three drugs studied. The limits of detection for the three drugs in serum were in the range of 0.160-0.302 μg/mL. Reproducibility expressed as the RSD of the recovery for ten replicated extractions at three different concentrations was found to be less than 8.93%. With a unique combination of surface functionality with magnetic cores, the restricted access magnetic particles may be adapted in automated and high