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Sample records for analysis structural chemical

  1. Uranium complexes with macrosyclic polyethers. Synthesis and structural chemical analysis

    International Nuclear Information System (INIS)

    This dissertation reports about studies on the chemical coordination behaviour of uranium of oxidation stages IV and VI with regard to twelve different macrocyclic ligands. For the preparation of the complexes, for every system a different method has been developed. The elementary analysis of the various complexes including the uranium had been done by X-ray fluorescence analysis, and the structural characterization proceeded via vibrational, uv-vis and emission spectroscopy as well as 1H-NMR and 13C-spin-lattice relaxation time studies. Conformational analysis of the polyethers used allowed the structural changes in the complexes to be observed. The structural analysis of the hydrous uranium VI crown ether complexes yielded information of characteristic features of these types of complexes. The first coordination sphere of the uranyl ion with covalently bonded anion remains unchanged. As to the water content, there is a certain range. Depending upon the solvent used, the complexes have two or four H2O molecules per formula unit. (orig./EF)

  2. Structural Analysis Of Alfa Fibers After Chemical Treatment

    Directory of Open Access Journals (Sweden)

    Zakaria Mouallif

    2015-02-01

    Full Text Available Nowadays, natural fibers are used as reinforcement in composite materials. The Alfa fibers have undergone an alkaline treatment with sodium hydroxide NaOH at a concentration of 10%, during an immersion period of two days. After drying, the Fourier transform infrared spectroscopy by attenuated total reflection (FTIR-ATR and X-ray diffraction (XRD were used for the analysis of the chemical properties of these fibers which were extracted from the plant Alfa of the region Al Haouz (Morocco in order to study the modifications resulting from the alkaline treatment. The results proved the presence of the cellulose, with an increase in its proportion in those fibers which have undergone an alkaline treatment with NaOH, the presence of lignin and pectin, as well as their disappearance after the alkaline extraction.

  3. Powerful chemical technique. [CSIR uses new x-ray diffractometer for structural chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    The CSIR's National Chemical Research Laboratory (NCRL) is now using one of the most powerful techniques available to determine the structure of molecules. It has recently acquired a Single Crystal X-ray Diffractometer. This powerful method provides the only means of determining the structure of certain compounds. NCRL scientists often carry out structure determinations to find out the relative or absolute stereochemistry of molecules. This is important when correlating physiological activity and structure, information which is necessary for synthesizing medicines with specific characteristics.

  4. ANALYSIS OF THE CHEMICAL COMPOSITION AND MORPHOLOGICAL STRUCTURE OF BANANA PSEUDO-STEM

    OpenAIRE

    Kun Li; Shiyu Fu; Huaiyu Zhan; Yao Zhan; Lucian A. Lucia

    2010-01-01

    An analysis of the chemical composition and anatomical structure of banana pseudo-stem was carried out using Light Microscopy (LM), Scanning Electron Microscopy (SEM), and Confocal Laser Scanning Microscopy (CLSM). The chemical analysis indicated there is a high holocellulose content and low lignin content in banana pseudo-stem compared with some other non-wood fiber resources. These results demonstrate that the banana pseudo-stem has potential value for pulping. In addition, we report for th...

  5. Chemical structure of wood charcoal by infrared spectroscopy and multivariate analysis.

    Science.gov (United States)

    Labbé, Nicole; Harper, David; Rials, Timothy; Elder, Thomas

    2006-05-17

    In this work, the effect of temperature on charcoal structure and chemical composition is investigated for four tree species. Wood charcoal carbonized at various temperatures is analyzed by mid infrared spectroscopy coupled with multivariate analysis and by thermogravimetric analysis to characterize the chemical composition during the carbonization process. The multivariate models of charcoal were able to distinguish between species and wood thermal treatments, revealing that the characteristics of the wood charcoal depend not only on the wood species, but also on the carbonization temperature. This work demonstrates the potential of mid infrared spectroscopy in the whiskey industry, from the identification and classification of the wood species for the mellowing process to the chemical characterization of the barrels after the toasting and charring process. PMID:19127715

  6. Combined Micro-chemical and Micro-structural Analysis of New Minerals Representing Extreme Conditions

    Science.gov (United States)

    Ma, C.; Tschauner, O. D.

    2015-12-01

    Recent improvements in micro-chemical analysis in combination with novel tools for micrometer-scale structural analysis of minerals from synchrotron X-ray diffraction open a pathway towards studies of mineral paragenesis that were previously not or barely accessible. Often mineral assemblies that represent extreme conditions also pose extreme challenges to analysis: very small size scale, complex matrix, minor amounts of material. Examples of such extreme, but also quite relevant environments are: a) High pressure shock-metamorphic minerals in meteorites and terrestrial impact sites, b) inclusions in diamonds from the deep mantle, c) ultrarefractory phases in Ca-Al-inlcusions from the solar nebula, d) presolar condensates. We show how a combination of synchrotron-based structural and semi-quantitative chemical techniques, with electron-microscopy based high-resolution imaging and fully quantitative chemical analysis and qualitative structural identification establish a powerful tool for discovery and characterization of important and interesting new minerals on micron- to submicron size scale.

  7. THz-Raman: accessing molecular structure with Raman spectroscopy for enhanced chemical identification, analysis, and monitoring

    Science.gov (United States)

    Heyler, Randy A.; Carriere, James T. A.; Havermeyer, Frank

    2013-05-01

    Structural analysis via spectroscopic measurement of rotational and vibrational modes is of increasing interest for many applications, since these spectra can reveal unique and important structural and behavioral information about a wide range of materials. However these modes correspond to very low frequency (~5cm-1 - 200cm-1, or 150 GHz-6 THz) emissions, which have been traditionally difficult and/or expensive to access through conventional Raman and Terahertz spectroscopy techniques. We report on a new, inexpensive, and highly efficient approach to gathering ultra-low-frequency Stokes and anti-Stokes Raman spectra (referred to as "THz-Raman") on a broad range of materials, opening potential new applications and analytical tools for chemical and trace detection, identification, and forensics analysis. Results are presented on explosives, pharmaceuticals, and common elements that show strong THz-Raman spectra, leading to clear discrimination of polymorphs, and improved sensitivity and reliability for chemical identification.

  8. A large scale analysis of information-theoretic network complexity measures using chemical structures.

    Directory of Open Access Journals (Sweden)

    Matthias Dehmer

    Full Text Available This paper aims to investigate information-theoretic network complexity measures which have already been intensely used in mathematical- and medicinal chemistry including drug design. Numerous such measures have been developed so far but many of them lack a meaningful interpretation, e.g., we want to examine which kind of structural information they detect. Therefore, our main contribution is to shed light on the relatedness between some selected information measures for graphs by performing a large scale analysis using chemical networks. Starting from several sets containing real and synthetic chemical structures represented by graphs, we study the relatedness between a classical (partition-based complexity measure called the topological information content of a graph and some others inferred by a different paradigm leading to partition-independent measures. Moreover, we evaluate the uniqueness of network complexity measures numerically. Generally, a high uniqueness is an important and desirable property when designing novel topological descriptors having the potential to be applied to large chemical databases.

  9. Identification numbers for chemical structures

    International Nuclear Information System (INIS)

    Several identification (ID) numbers for chemical structures (connectivity ID number, prime ID number, weighted ID number) are analyzed and tested until a counterexample (a pair of structures with the same ID number) is found. The analysis is carried out for acyclic structures with up to 20 atoms, trees with up to 20 points, benzenoid graphs and polyhexes with up to 10 hexagons, and all connected graphs with up to 6 points. Although all the (chemical) ID numbers studied are highly selective for many families of (molecular) graphs, none of them are unique; in all three cases the counterexamples are found. However, the greatest discriminative power is shown by the weighted ID number

  10. Chemical Security Analysis Center

    Data.gov (United States)

    Federal Laboratory Consortium — In 2006, by Presidential Directive, DHS established the Chemical Security Analysis Center (CSAC) to identify and assess chemical threats and vulnerabilities in the...

  11. Structure validation in chemical crystallography.

    Science.gov (United States)

    Spek, Anthony L

    2009-02-01

    Automated structure validation was introduced in chemical crystallography about 12 years ago as a tool to assist practitioners with the exponential growth in crystal structure analyses. Validation has since evolved into an easy-to-use checkCIF/PLATON web-based IUCr service. The result of a crystal structure determination has to be supplied as a CIF-formatted computer-readable file. The checking software tests the data in the CIF for completeness, quality and consistency. In addition, the reported structure is checked for incomplete analysis, errors in the analysis and relevant issues to be verified. A validation report is generated in the form of a list of ALERTS on the issues to be corrected, checked or commented on. Structure validation has largely eliminated obvious problems with structure reports published in IUCr journals, such as refinement in a space group of too low symmetry. This paper reports on the current status of structure validation and possible future extensions.

  12. Test results of chemical reactivity test (CRT) analysis of structural materials and explosives

    Energy Technology Data Exchange (ETDEWEB)

    Back, P.S.; Barnhart, B.V.; Walters, R.R.; Haws, L.D.; Collins, L.W.

    1980-03-21

    The chemical reactivity test, CRT, is a procedure used to screen the compatibility of component structure materials with explosives. This report contains the results of CRT materials evaluations conducted at Mound Facility. Data about materials combinations are catalogued both under the name of the explosive and the nonexplosive.

  13. Nano-structural and Nano-chemical analysis of dissimilar metal weld interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoung Joon; Shin, Sang Hoon; Kim, Jong Jin; Jung, Ju Ang; Kim, Ji Hyun [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2012-05-15

    Dissimilar Metal Welds (DMWs) is generally applied to nuclear power plants for manufacturing and machining in structural components such as reactor pressure vessels and pressurizer nozzles. Alloy 152 is used frequently as filler metal in the manufacture of the DMW in light water reactors to join the low alloy steel pressure vessel nozzles and steam generator nozzles to nickel-based wrought alloy or austenitic stainless steel components. However, in recent years cracking phenomena has been observed in the welded joints. Concerns have been raised to the integrity and reliability in the joint transition zone due to the high susceptibility of the heat affected zone (HAZ) and the fusion boundary (FB) to stress corrosion cracking in combination with thermal aging. Since the material microstructure and chemical composition are key parameters affecting the stress corrosion cracking, improving the understanding of stress corrosion cracking at the FB region requires fundamental understanding of the unique microstructure of the FB region in DMW. Despite the potential degradation and consequent risk in the DMW, there is still a lack of the fundamental understanding of microstructure in the FB region, in particular the region containing unidentified band structures near the FB. The scale of the microstructure in modern metallic materials is becoming increasingly smaller. The 3-dimensional atom probe tomography (3D APT) has a truly quantitative analytical capability to characterize nanometer scale particles in metallic materials, thus its application to the microstructural analysis in multi-component metallic materials provides critical information on the mechanism of nanoscale microstructural evolution. The 3D APT is a microscope that allows the reconstruction of 3D 'atom maps'. These reconstructions can be interrogated and interpreted to determine the nanoscale chemistry of the material. Therefore, the current study is aiming at the establishment of detail procedure

  14. Analysis of the relationship between the structure and aromatic properties of chemical compounds.

    Science.gov (United States)

    Debska, Barbara; Guzowska-Swider, Barbara

    2003-04-01

    This paper presents the results of research on the relationship between the structure and odour properties of a selection of chemical compounds. The research concerns five groups of esters, each with a different smell: almond, apricot, apple, pineapple and rose. The supposed relationship between the smell and certain selected attributes of each molecule was examined by various pattern recognition techniques using programs developed in the Department of Computer Chemistry at Rzeszów University of Technology.

  15. Predicting the redox state and secondary structure of cysteine residues using multi-dimensional classification analysis of NMR chemical shifts.

    Science.gov (United States)

    Wang, Ching-Cheng; Lai, Wen-Chung; Chuang, Woei-Jer

    2016-09-01

    A tool for predicting the redox state and secondary structure of cysteine residues using multi-dimensional analyses of different combinations of nuclear magnetic resonance (NMR) chemical shifts has been developed. A data set of cysteine [Formula: see text], (13)C(α), (13)C(β), (1)H(α), (1)H(N), and (15)N(H) chemical shifts was created, classified according to redox state and secondary structure, using a library of 540 re-referenced BioMagResBank (BMRB) entries. Multi-dimensional analyses of three, four, five, and six chemical shifts were used to derive rules for predicting the structural states of cysteine residues. The results from 60 BMRB entries containing 122 cysteines showed that four-dimensional analysis of the C(α), C(β), H(α), and N(H) chemical shifts had the highest prediction accuracy of 100 and 95.9 % for the redox state and secondary structure, respectively. The prediction of secondary structure using 3D, 5D, and 6D analyses had the accuracy of ~90 %, suggesting that H(N) and [Formula: see text] chemical shifts may be noisy and made the discrimination worse. A web server (6DCSi) was established to enable users to submit NMR chemical shifts, either in BMRB or key-in formats, for prediction. 6DCSi displays predictions using sets of 3, 4, 5, and 6 chemical shifts, which shows their consistency and allows users to draw their own conclusions. This web-based tool can be used to rapidly obtain structural information regarding cysteine residues directly from experimental NMR data.

  16. Chemical substructure analysis in toxicology

    Energy Technology Data Exchange (ETDEWEB)

    Beauchamp, R.O. Jr. [Center for Information on Toxicology and Environment, Raleigh, NC (United States)

    1990-12-31

    A preliminary examination of chemical-substructure analysis (CSA) demonstrates the effective use of the Chemical Abstracts compound connectivity file in conjunction with the bibliographic file for relating chemical structures to biological activity. The importance of considering the role of metabolic intermediates under a variety of conditions is illustrated, suggesting structures that should be examined that may exhibit potential activity. This CSA technique, which utilizes existing large files accessible with online personal computers, is recommended for use as another tool in examining chemicals in drugs. 2 refs., 4 figs.

  17. Chemical Space Mapping and Structure-Activity Analysis of the ChEMBL Antiviral Compound Set.

    Science.gov (United States)

    Klimenko, Kyrylo; Marcou, Gilles; Horvath, Dragos; Varnek, Alexandre

    2016-08-22

    Curation, standardization and data fusion of the antiviral information present in the ChEMBL public database led to the definition of a robust data set, providing an association of antiviral compounds to seven broadly defined antiviral activity classes. Generative topographic mapping (GTM) subjected to evolutionary tuning was then used to produce maps of the antiviral chemical space, providing an optimal separation of compound families associated with the different antiviral classes. The ability to pinpoint the specific spots occupied (responsibility patterns) on a map by various classes of antiviral compounds opened the way for a GTM-supported search for privileged structural motifs, typical for each antiviral class. The privileged locations of antiviral classes were analyzed in order to highlight underlying privileged common structural motifs. Unlike in classical medicinal chemistry, where privileged structures are, almost always, predefined scaffolds, privileged structural motif detection based on GTM responsibility patterns has the decisive advantage of being able to automatically capture the nature ("resolution detail"-scaffold, detailed substructure, pharmacophore pattern, etc.) of the relevant structural motifs. Responsibility patterns were found to represent underlying structural motifs of various natures-from very fuzzy (groups of various "interchangeable" similar scaffolds), to the classical scenario in medicinal chemistry (underlying motif actually being the scaffold), to very precisely defined motifs (specifically substituted scaffolds). PMID:27410486

  18. Structural and chemical determination of the new nanolaminated carbide Mo2Ga2C from first principles and materials analysis

    International Nuclear Information System (INIS)

    Following our recent discovery of a new nanolaminated carbide, Mo2Ga2C, we herein present a detailed structural and chemical analysis of this phase based on ab initio calculations, X-ray photoelectron spectroscopy, high resolution scanning transmission electron microscopy, and neutron powder diffraction. Calculations suggest an energetically and dynamically stable structure for C in the octahedral sites between the Mo layers, with Ga bilayers – stacked in a simple hexagonal arrangement – between the Mo2C layers. The predicted elastic properties are below those of the related nanolaminate Mo2GaC. The predicted structure, including lattice parameters and atomic positions, is experimentally confirmed

  19. Chemical exchange program analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Waffelaert, Pascale

    2007-09-01

    As part of its EMS, Sandia performs an annual environmental aspects/impacts analysis. The purpose of this analysis is to identify the environmental aspects associated with Sandia's activities, products, and services and the potential environmental impacts associated with those aspects. Division and environmental programs established objectives and targets based on the environmental aspects associated with their operations. In 2007 the most significant aspect identified was Hazardous Materials (Use and Storage). The objective for Hazardous Materials (Use and Storage) was to improve chemical handling, storage, and on-site movement of hazardous materials. One of the targets supporting this objective was to develop an effective chemical exchange program, making a business case for it in FY07, and fully implementing a comprehensive chemical exchange program in FY08. A Chemical Exchange Program (CEP) team was formed to implement this target. The team consists of representatives from the Chemical Information System (CIS), Pollution Prevention (P2), the HWMF, Procurement and the Environmental Management System (EMS). The CEP Team performed benchmarking and conducted a life-cycle analysis of the current management of chemicals at SNL/NM and compared it to Chemical Exchange alternatives. Those alternatives are as follows: (1) Revive the 'Virtual' Chemical Exchange Program; (2) Re-implement a 'Physical' Chemical Exchange Program using a Chemical Information System; and (3) Transition to a Chemical Management Services System. The analysis and benchmarking study shows that the present management of chemicals at SNL/NM is significantly disjointed and a life-cycle or 'Cradle-to-Grave' approach to chemical management is needed. This approach must consider the purchasing and maintenance costs as well as the cost of ultimate disposal of the chemicals and materials. A chemical exchange is needed as a mechanism to re-apply chemicals on site. This

  20. Structural analysis of CdS thin films obtained by multiple dips of oscillating chemical bath

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez Lazos, C.D. [Seccion de Electronica del Estado Solido, Centro de Investigacion y de Estudios Avanzados, Av. Instituto Politecnico Nacional 2508, Col. San Pedro Zacatenco, 07360 Mexico, D.F. (Mexico); Rosendo, E., E-mail: erosendo@siu.buap.m [Centro de Investigacion en Dispositivos Semiconductores, Universidad Autonoma de Puebla, 14 Sur y San Claudio, Col. San Manuel, C.P. 72570, Puebla (Mexico); Ortega, M. [Seccion de Electronica del Estado Solido, Centro de Investigacion y de Estudios Avanzados, Av. Instituto Politecnico Nacional 2508, Col. San Pedro Zacatenco, 07360 Mexico, D.F. (Mexico); Oliva, A.I. [Departamento de Fisica Aplicada, Centro de Investigacion y de Estudios Avanzados, Unidad Merida, A.P. 73 Cordemex, 97310 Merida, Yucatan (Mexico); Tapia, O.; Diaz, T.; Juarez, H.; Garcia, G. [Centro de Investigacion en Dispositivos Semiconductores, Universidad Autonoma de Puebla, 14 Sur y San Claudio, Col. San Manuel, C.P. 72570, Puebla (Mexico); Rubin, M. [Facultad de Ciencias de la Computacion, 14 Sur y San Claudio, Col. San Manuel, C.P. 72570, Puebla (Mexico)

    2009-11-25

    Highly oriented CdS thin films with thicknesses greater than 1 mum were deposited by multiple dips, using oscillating chemical bath deposition (OCBD) at the bath temperature of 75 deg. C, and deposition time ranging from 15 to 75 min for a single dip. Samples with different thickness were prepared by repeating the deposition process for two and three times. The films deposited by a single dip have the alpha-greenockite structure showing the (0 0 2) as preferred orientation, as indicated by the X-ray diffraction measurements. This notable characteristic is preserved in the samples obtained from two or three dips. The crystallite size for the samples deposited by a single dip depends on the deposition time, because it varied from 23 to 37 nm as the deposition time increased. Nevertheless for samples deposited by two and three dips, the grain size shows no noticeable change, being about 22 nm.

  1. Secondary structural analysis of proteins based on 13C chemical shift assignments in unresolved solid-state NMR spectra enhanced by fragmented structure database

    International Nuclear Information System (INIS)

    Magic-angle-spinning solid-state 13C NMR spectroscopy is useful for structural analysis of non-crystalline proteins. However, the signal assignments and structural analysis are often hampered by the signal overlaps primarily due to minor structural heterogeneities, especially for uniformly-13C,15N labeled samples. To overcome this problem, we present a method for assigning 13C chemical shifts and secondary structures from unresolved two-dimensional 13C–13C MAS NMR spectra by spectral fitting, named reconstruction of spectra using protein local structures (RESPLS). The spectral fitting was conducted using databases of protein fragmented structures related to 13Cα, 13Cβ, and 13C′ chemical shifts and cross-peak intensities. The experimental 13C–13C inter- and intra-residue correlation spectra of uniformly isotope-labeled ubiquitin in the lyophilized state had a few broad peaks. The fitting analysis for these spectra provided sequence-specific Cα, Cβ, and C′ chemical shifts with an accuracy of about 1.5 ppm, which enabled the assignment of the secondary structures with an accuracy of 79 %. The structural heterogeneity of the lyophilized ubiquitin is revealed from the results. Test of RESPLS analysis for simulated spectra of five different types of proteins indicated that the method allowed the secondary structure determination with accuracy of about 80 % for the 50–200 residue proteins. These results demonstrate that the RESPLS approach expands the applicability of the NMR to non-crystalline proteins exhibiting unresolved 13C NMR spectra, such as lyophilized proteins, amyloids, membrane proteins and proteins in living cells.

  2. Chemical process hazards analysis

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    The Office of Worker Health and Safety (EH-5) under the Assistant Secretary for the Environment, Safety and Health of the US Department (DOE) has published two handbooks for use by DOE contractors managing facilities and processes covered by the Occupational Safety and Health Administration (OSHA) Rule for Process Safety Management of Highly Hazardous Chemicals (29 CFR 1910.119), herein referred to as the PSM Rule. The PSM Rule contains an integrated set of chemical process safety management elements designed to prevent chemical releases that can lead to catastrophic fires, explosions, or toxic exposures. The purpose of the two handbooks, ``Process Safety Management for Highly Hazardous Chemicals`` and ``Chemical Process Hazards Analysis,`` is to facilitate implementation of the provisions of the PSM Rule within the DOE. The purpose of this handbook ``Chemical Process Hazards Analysis,`` is to facilitate, within the DOE, the performance of chemical process hazards analyses (PrHAs) as required under the PSM Rule. It provides basic information for the performance of PrHAs, and should not be considered a complete resource on PrHA methods. Likewise, to determine if a facility is covered by the PSM rule, the reader should refer to the handbook, ``Process Safety Management for Highly Hazardous Chemicals`` (DOE- HDBK-1101-96). Promulgation of the PSM Rule has heightened the awareness of chemical safety management issues within the DOE. This handbook is intended for use by DOE facilities and processes covered by the PSM rule to facilitate contractor implementation of the PrHA element of the PSM Rule. However, contractors whose facilities and processes not covered by the PSM Rule may also use this handbook as a basis for conducting process hazards analyses as part of their good management practices. This handbook explains the minimum requirements for PrHAs outlined in the PSM Rule. Nowhere have requirements been added beyond what is specifically required by the rule.

  3. Structural and chemical analysis of gadolinium halides encapsulated within WS2 nanotubes

    Science.gov (United States)

    Anumol, E. A.; Enyashin, Andrey N.; Batra, Nitin M.; Costa, Pedro M. F. J.; Deepak, Francis Leonard

    2016-06-01

    The hollow cavities of nanotubes serve as templates for the growth of size- and shape-confined functional nanostructures, giving rise to novel materials and properties. In this work, considering their potential application as MRI contrast agents, gadolinium halides are encapsulated within the hollow cavities of WS2 nanotubes by capillary filling to obtain GdX3@WS2 nanotubes (where X = Cl, Br or I and @ means encapsulated in). Aberration corrected scanning/transmission electron microscopy (S/TEM) and spectroscopy is employed to understand the morphology and composition of the GdI3@WS2 nanotubes. The three dimensional morphology is studied with STEM tomography but understanding the compositional information is non-trivial due to the presence of multiple high atomic number elements. Therefore, energy dispersive X-ray spectroscopy (EDS) tomography was employed revealing the three dimensional chemical composition. Molecular dynamics simulations of the filling procedure shed light into the mechanics behind the formation of the confined gadolinium halide crystals. The quasi-1D system employed here serves as an example of a TEM-based chemical nanotomography method that could be extended to other materials, including beam-sensitive soft materials.The hollow cavities of nanotubes serve as templates for the growth of size- and shape-confined functional nanostructures, giving rise to novel materials and properties. In this work, considering their potential application as MRI contrast agents, gadolinium halides are encapsulated within the hollow cavities of WS2 nanotubes by capillary filling to obtain GdX3@WS2 nanotubes (where X = Cl, Br or I and @ means encapsulated in). Aberration corrected scanning/transmission electron microscopy (S/TEM) and spectroscopy is employed to understand the morphology and composition of the GdI3@WS2 nanotubes. The three dimensional morphology is studied with STEM tomography but understanding the compositional information is non-trivial due to the

  4. Structural and Chemical Analysis of Gadolinium Halides Encapsulated within WS 2 Nanotubes

    KAUST Repository

    Anumol, E A

    2016-05-18

    The hollow cavities of nanotubes could serve as templates for the growth of size- and shape-confined functional nanostructures, giving rise to novel materials and properties. In this work, considering their potential application as MRI contrast agents, gadolinium halides are encapsulated within the hollow cavities of inorganic nanotubes of WS2 by capillary filling to obtain GdX3@WS2 nanotubes (where X = Cl, Br or I and @ means encapsulated in). Aberration corrected scanning/transmission electron microscopy (S/TEM) and spectroscopy is employed to understand the morphology and composition of the GdI3@WS2 nanotubes. The three dimensional morphology is studied with STEM tomography but understanding the compositional information is a non-trivial matter due to the presence of multiple high atomic number elements. Therefore, energy dispersive X-ray spectroscopy (EDS) tomography was employed revealing the three dimensional chemical composition. Molecular dynamics simulations of the filling procedure shed light into the mechanics behind the formation of the confined gadolinium halide crystals. The quasi-1D system employed here serves as an example of a TEM-based chemical nanotomography method that could be extended to other materials, including beam-sensitive soft materials.

  5. Structural and Chemical Analysis of the Zirconia-Veneering Ceramic Interface.

    Science.gov (United States)

    Inokoshi, M; Yoshihara, K; Nagaoka, N; Nakanishi, M; De Munck, J; Minakuchi, S; Vanmeensel, K; Zhang, F; Yoshida, Y; Vleugels, J; Naert, I; Van Meerbeek, B

    2016-01-01

    The interfacial interaction of veneering ceramic with zirconia is still not fully understood. This study aimed to characterize morphologically and chemically the zirconia-veneering ceramic interface. Three zirconia-veneering conditions were investigated: 1) zirconia-veneering ceramic fired on sandblasted zirconia, 2) zirconia-veneering ceramic on as-sintered zirconia, and 3) alumina-veneering ceramic (lower coefficient of thermal expansion [CTE]) on as-sintered zirconia. Polished cross-sectioned ceramic-veneered zirconia specimens were examined using field emission gun scanning electron microscopy (Feg-SEM). In addition, argon-ion thinned zirconia-veneering ceramic interface cross sections were examined using scanning transmission electron microscopy (STEM)-energy dispersive X-ray spectrometry (EDS) at high resolution. Finally, the zirconia-veneering ceramic interface was quantitatively analyzed for tetragonal-to-monoclinic phase transformation and residual stress using micro-Raman spectroscopy (µRaman). Feg-SEM revealed tight interfaces for all 3 veneering conditions. High-resolution transmission electron microscopy (HRTEM) disclosed an approximately 1.0-µm transformed zone at sandblasted zirconia, in which distinct zirconia grains were no longer observable. Straight grain boundaries and angular grain corners were detected up to the interface of zirconia- and alumina-veneering ceramic with as-sintered zirconia. EDS mapping disclosed within the zirconia-veneering ceramic a few nanometers thick calcium/aluminum-rich layer, touching the as-sintered zirconia base, with an equally thick silicon-rich/aluminum-poor layer on top. µRaman revealed t-ZrO2-to-m-ZrO2 phase transformation and residual compressive stress at the sandblasted zirconia surface. The difference in CTE between zirconia- and the alumina-veneering ceramic resulted in residual tensile stress within the zirconia immediately adjacent to its interface with the veneering ceramic. The rather minor chemical

  6. The Virtual Product-Process Design Laboratory for Structured Chemical Product Design and Analysis

    DEFF Research Database (Denmark)

    Mattei, Michele; Yunus, Nor Alafiza Binti; Kalakul, Sawitree;

    2014-01-01

    The objective of this paper is to present new methods for design of chemicals based formulated products and their implementation in the software, the Virtual Product-Process Design Laboratory. The new products are tailor-made blended liquid products and emulsion-based products. The new software...... employs a template approach, where each template follows the same common steps in the workflow for design of formulated products, but has the option to employ different product specific property models, data and calculation routines, when necessary. With the new additions, the software is able to support....... Output from the software is a small set of most promising product candidates and a short list of recommended experiments that can validate and further fine-tune the product composition. The application of the new features is highlighted through two case studies relative to an emulsion-based product...

  7. Radiometric chemical analysis

    International Nuclear Information System (INIS)

    The radiometric method of analysis is noted for its sensitivity and its simplicity in both apparatus and procedure. A few inexpensive radioactive reagents permit the analysis of a wide variety of chemical elements and compounds. Any particular procedure is generally applicable over a very wide range of concentrations. It is potentially an analytical method of great industrial significance. Specific examples of analyses are cited to illustrate the potentialities of ordinary equipment. Apparatus specifically designed for radiometric chemistry may shorten the time required, and increase the precision and accuracy for routine analyses. A sensitive and convenient apparatus for the routine performance of radiometric chemical analysis is a special type of centrifuge which has been used in obtaining the data presented in this paper. The radioactivity of the solution is measured while the centrifuge is spinning. This device has been used as the basis for an automatic analyser for phosphate ion, programmed to follow a sequence of unknown sampling, reagent mixing, centrifugation, counting data presentation, and phosphate replenishment. This analyser can repeatedly measure phosphate-concentration in the range of 5 to 50 ppm with an accuracy of ±5%. (author)

  8. RR Lyrae variables in the Small Magellanic Cloud - II. The extended area: chemical and structural analysis

    CERN Document Server

    Kapakos, Efstratios

    2012-01-01

    We have performed the Fourier decomposition analysis of 8- and 13-year V-band light curves of a carefully selected sample of 454 fundamental-mode RR Lyrae variables (RRab type), detected in a 14 square degree area of the Small Magellanic Cloud (SMC) and listed in the Optical Gravitational Lensing Experiment, phase III, Catalogue of Variable Stars. The Fourier decomposition parameters were used to derive metal abundances and distance moduli, following the methodology described by Kapakos, Hatzidimitriou & Soszy\\'nski. The average metal abundance of the RRab stars on the new scale of Carretta et al. was found to be = -1.69pm0.41 dex (std, with a standard error of 0.02 dex). A tentative metallicity gradient of -0.013pm0.007 dex/kpc was detected, with increasing metal abundance towards the dynamical center of the SMC, but selection effects are also discussed. The distance modulus of the SMC was re-estimated and was found to be = 19.13pm0.19 (std) in a distance scale where the distance modulus of the Large M...

  9. Trends in information theory-based chemical structure codification.

    Science.gov (United States)

    Barigye, Stephen J; Marrero-Ponce, Yovani; Pérez-Giménez, Facundo; Bonchev, Danail

    2014-08-01

    This report offers a chronological review of the most relevant applications of information theory in the codification of chemical structure information, through the so-called information indices. Basically, these are derived from the analysis of the statistical patterns of molecular structure representations, which include primitive global chemical formulae, chemical graphs, or matrix representations. Finally, new approaches that attempt to go "back to the roots" of information theory, in order to integrate other information-theoretic measures in chemical structure coding are discussed.

  10. CLAYFORM: a FORTRAN 77 computer program apportioning the constituents in the chemical analysis of a clay or other silicate mineral into a structural formula

    Science.gov (United States)

    Bodine, M.W., Jr.

    1987-01-01

    The FORTRAN 77 computer program CLAYFORM apportions the constituents of a conventional chemical analysis of a silicate mineral into a user-selected structure formula. If requested, such as for a clay mineral or other phyllosilicate, the program distributes the structural formula components into appropriate default or user-specified structural sites (tetrahedral, octahedral, interlayer, hydroxyl, and molecular water sites), and for phyllosilicates calculates the layer (tetrahedral, octahedral, and interlayer) charge distribution. The program also creates data files of entered analyses for subsequent reuse. ?? 1987.

  11. Structural and Physico-Chemical Interpretation (SPCI) of QSAR Models and Its Comparison with Matched Molecular Pair Analysis.

    Science.gov (United States)

    Polishchuk, Pavel; Tinkov, Oleg; Khristova, Tatiana; Ognichenko, Ludmila; Kosinskaya, Anna; Varnek, Alexandre; Kuz'min, Victor

    2016-08-22

    This paper describes the Structural and Physico-Chemical Interpretation (SPCI) approach, which is an extension of a recently reported method for interpretation of quantitative structure-activity relationship (QSAR) models. This approach can efficiently be used to reveal structural motifs and the major physicochemical factors affecting the investigated properties. Its efficacy was demonstrated both on the classical Free-Wilson data set and on several data sets with different end points (permeability of the blood-brain barrier, fibrinogen receptor antagonists, acute oral toxicity). Structure-activity patterns extracted from QSAR models with SPCI were in good correspondence with experimentally observed relationships and molecular docking, regardless of the machine learning method used. Comparison of SPCI with the matched molecular pair (MMP) method clearly shows an advantage of our approach over MMP, especially for small or structurally diverse data sets. The developed approach has been implemented in the SPCI software tool with a graphical user interface, which is publicly available at http://qsar4u.com/pages/sirms_qsar.php . PMID:27419846

  12. Structure, characteristics and potential of commercial equipment Total Reflection X Ray Fluorescence for multielemental chemical analysis: Current State

    International Nuclear Information System (INIS)

    The method Total Reflection X-Ray Fluorescence for chemical multielemental analysis has evolved in the last years with the availability of commercial systems for applications in the field of electronics and chemical multielemental analysis in samples of mineral and biological origin. The basic components of these equipment cam be summarized in a system of excitement, a geometric arrangement (optics) for collimate and monochromatize the primary radiation, a X-rays detector, and the electronic si stem for spectral data acquisition including the software for spectra unfolding, qualitative and quantitative analysis, and the complete instrument operation. Additionally the makers offer the conventional 45 degrees geometry for the excitement solid and liquid samples of bigger volume in direct form. The available bibliographical and commercial information to the moment of preparing this lecture, basically reports the following types of components for the X-rays spectrometers in geometry of total reflection chemical multielemental analysis (they are excluded those RTFX equipment dedicated to the electronic industry for quality control of Si wafers purity used for the production of circuits (chips). Excitation: X-rays tube of high vacuum with power among 1300 to 2000 watts and different types of anode; X-rays ceramic metal tube, with power up to 40 watts, and anode of molybdenum, tug steno, etc. Detection: detector semiconductor of silicon-lithium cooled with liquid nitrogen; detector of solid state silicon cooled electrically (Si-PI N diode or detector of diffused silicon Sdd). Optics: multi stratum monochromator; multi stratum Ni-C monochromator; double multi stratum monochromator. Electronic: spectroscopical amplifier espectroscopico and ana logical digital convertor adapted to a personal computer IBM compatible, with software for qualitative and quantitative analysis of samples by means of Windows, and for the complete operation of the analyzer from the Pc. In this work

  13. Chemical Analysis Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Uses state-of-the-art instrumentation for qualitative and quantitative analysis of organic and inorganic compounds, and biomolecules from gas, liquid, and...

  14. Chemical and structural analysis of the bone-implant interface by TOF-SIMS, SEM, FIB and TEM: Experimental study in animal

    Science.gov (United States)

    Palmquist, Anders; Emanuelsson, Lena; Sjövall, Peter

    2012-06-01

    Although bone-anchored implants are widely used in reconstructive medicine, the mechanism of osseointegration is still not fully understood. Novel analytical tools are needed to further understand this process, where both the chemical and structural aspects of the bone-implant interface are important. The aim of this study was to evaluate the advantages of combining time-of-flight secondary ion mass spectroscopy (TOF-SIMS) with optical (LM), scanning (SEM) and transmission electron microscopy (TEM) techniques for studying the bone-implant interface of bone-anchored implants. Laser-modified titanium implants with surrounded bone retrieved after 8 weeks healing in rabbit were dehydrated and resin embedded. Three types of sample preparation were studied to evaluate the information gained by combining TOF-SIMS, SEM, FIB and TEM. The results show that imaging TOF-SIMS can provide detailed chemical information, which in combination with structural information from microscopy methods provide a more complete characterization of anatomical structures at the bone-implant interface. By investigating various sample preparation techniques, it is shown that grinded cross section samples can be used for chemical imaging using TOF-SIMS, if careful consideration of potential preparation artifacts is taken into account. TOF-SIMS analysis of FIB-prepared bone/implant cross section samples show distinct areas corresponding to bone tissue and implant with a sharp interface, although without chemical information about the organic components.

  15. Microprocessors in automatic chemical analysis

    International Nuclear Information System (INIS)

    Application of microprocessors to programming and computing of solutions chemical analysis by a sequential technique is examined. Safety, performances reliability are compared to other methods. An example is given on uranium titration by spectrophotometry

  16. A chemometric analysis of ligand-induced changes in intrinsic fluorescence of folate binding protein indicates a link between altered conformational structure and physico-chemical characteristics

    DEFF Research Database (Denmark)

    Bruun, Susanne W; Holm, Jan; Hansen, Steen Ingemann;

    2009-01-01

    Ligand binding alters the conformational structure and physico-chemical characteristics of bovine folate binding protein (FBP). For the purpose of achieving further information we analyzed ligand (folate and methotrexate)-induced changes in the fluorescence landscape of FBP. Fluorescence excitation...... of folate accords fairly well with the disappearance of strongly hydrophobic tryptophan residues from the solvent-exposed surface of FBP. The PARAFAC has thus proven useful to establish a hitherto unexplained link between parallel changes in conformational structure and physico-chemical characteristics...... of FBP induced by folate binding. Parameters for ligand binding derived from PARAFAC analysis of the fluorescence data were qualitatively and quantitatively similar to those obtained from binding of radiofolate to FBP. Herein, methotrexate exhibited a higher affinity for FBP than in competition...

  17. Quantitative chemical-structure evaluation using atom probe tomography: Short-range order analysis of Fe–Al

    Energy Technology Data Exchange (ETDEWEB)

    Marceau, R.K.W., E-mail: r.marceau@deakin.edu.au [Institute for Frontier Materials, Deakin University, Geelong, VIC 3216 (Australia); Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf (Germany); Ceguerra, A.V.; Breen, A.J. [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006 (Australia); Raabe, D. [Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf (Germany); Ringer, S.P. [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006 (Australia)

    2015-10-15

    Short-range-order (SRO) has been quantitatively evaluated in an Fe–18Al (at%) alloy using atom probe tomography (APT) data and by calculation of the generalised multicomponent short-range order (GM-SRO) parameters, which have been determined by shell-based analysis of the three-dimensional atomic positions. The accuracy of this method with respect to limited detector efficiency and spatial resolution is tested against simulated D0{sub 3} ordered data. Whilst there is minimal adverse effect from limited atom probe instrument detector efficiency, the combination of this with imperfect spatial resolution has the effect of making the data appear more randomised. The value of lattice rectification of the experimental APT data prior to GM-SRO analysis is demonstrated through improved information sensitivity. - Highlights: • Short-range-order (SRO) is quantitatively evaluated using atom probe tomography data. • Chemical species-specific SRO parameters have been calculated. • The accuracy of this method is tested against simulated D0{sub 3} ordered data. • Imperfect spatial resolution combined with finite detector efficiency causes a randomising effect. • Lattice rectification of the data prior to GM-SRO analysis is demonstrated to improve information sensitivity.

  18. A worldwide analysis of within-canopy variations in leaf structural, chemical and physiological traits across plant functional types.

    Science.gov (United States)

    Niinemets, Ülo; Keenan, Trevor F; Hallik, Lea

    2015-02-01

    Extensive within-canopy light gradients importantly affect the photosynthetic productivity of leaves in different canopy positions and lead to light-dependent increases in foliage photosynthetic capacity per area (AA). However, the controls on AA variations by changes in underlying traits are poorly known. We constructed an unprecedented worldwide database including 831 within-canopy gradients with standardized light estimates for 304 species belonging to major vascular plant functional types, and analyzed within-canopy variations in 12 key foliage structural, chemical and physiological traits by quantitative separation of the contributions of different traits to photosynthetic acclimation. Although the light-dependent increase in AA is surprisingly similar in different plant functional types, they differ fundamentally in the share of the controls on AA by constituent traits. Species with high rates of canopy development and leaf turnover, exhibiting highly dynamic light environments, actively change AA by nitrogen reallocation among and partitioning within leaves. By contrast, species with slow leaf turnover exhibit a passive AA acclimation response, primarily determined by the acclimation of leaf structure to growth light. This review emphasizes that different combinations of traits are responsible for within-canopy photosynthetic acclimation in different plant functional types, and solves an old enigma of the role of mass- vs area-based traits in vegetation acclimation. PMID:25318596

  19. Chemical and structural analysis of enhanced biochars: thermally treated mixtures of biochar, chicken litter, clay and minerals.

    Science.gov (United States)

    Lin, Y; Munroe, P; Joseph, S; Ziolkowski, A; van Zwieten, L; Kimber, S; Rust, J

    2013-03-01

    In this study biochar mixtures comprising a Jarrah-based biochar, chicken litter (CL), clay and other minerals were thermally treated, via torrefaction, at moderate temperatures (180 and 220 °C). The objectives of this treatment were to reduce N losses from CL during processing and to determine the effect of both the type of added clay and the torrefaction temperature on the structural and chemical properties of the final product, termed as an enhanced biochar (EB). Detailed characterisation indicated that the EBs contained high concentrations of plant available nutrients. Both the nutrient content and plant availability were affected by torrefaction temperature. The higher temperature (220 °C) promoted the greater decomposition of organic matter in the CL and dissociated labile carbon from the Jarrah-based biochar, which produced a higher concentration of dissolved organic carbon (DOC). This DOC may assist to solubilise mineral P, and may also react with both clay and minerals to block active sites for P adsorption. This subsequently resulted in higher concentrations of plant available P. Nitrogen loss was minimised, with up to 73% of the initial total N contained in the feedstock remaining in the final EB. However, N availability was affected by both torrefaction temperature and the nature of the clay minerals added.

  20. Structural and chemical analysis of grain boundaries and tellurium precipitates in commercial Cd1-xZnxTe

    International Nuclear Information System (INIS)

    The structure and chemistry of grain boundaries in commercial Cd1-xZnxTe, prepared by the high-pressure Bridgman technique, have been analyzed using transmission electron microscopy, scanning electron microscopy, infrared-light microscopy and visible-light microscopy. These analyses show that the grain boundaries inside the Cd1-xZnxTe materials are decorated with tellurium precipitates. Analysis of a tellurium precipitate at a grain boundary by transmission electron microscopy and selected-area electron diffraction found the precipitate to consist of a single, saucer-shaped grain. Electron diffraction from the precipitate was consistent with the trigonal phase of tellurium (space group P3121), which is the equilibrium phase at room temperature and atmospheric pressure. This precipitate was found to be aligned with one of the adjacent CZT grains such that the tellurium (0 bar 111) planes were nearly parallel to the CZT (111) planes. High-resolution transmission electron microscopy of the Te/Cd1-xZnxTe interface showed no tertiary phase at the interface. The structures of the grain boundaries and the Te/Cd1-xZnxTe interface are discussed and related to their possible implications on Cd1-xZnxTe gamma-ray detector performance

  1. An Online System for Drug Chemical Structure Analysis%药物化学结构在线分析系统

    Institute of Scientific and Technical Information of China (English)

    王志刚; 陈鑫; 谢丽芳; 彭屹; 张正国

    2012-01-01

    High-throughput screening of drug structure databases can assist drug design. In this paper,the information of 4886 drugs' chemical structure from DrugBank database was abtained and a free online platform for analysis of the chemical structure of drugs was built. Drug pairs similarity matrix was pre-calculated and stored in system background. This makes high-throughput drug structure analysis much faster. Drugs' generic name,commercial names and alias can be searched in this platform. Drugs that have similar structure to the specific drug can be retrieved. Drug clustering can be visualized. Using this system,the drugs target to same protein is more similar in chemical structure which may be validated. This online system can be called ' Drug and Disease' at http://122.70.220.99/bme.%高通量的筛选药物结构数据库,可以辅助药物设计.该文从DrugBank数据库获取4886种药物的化学结构信息,建立了一个免费的在线药物化学结构分析平台.基于Tanimoto系数预先计算了药物两两化学结构相似性矩阵作为后台数据,从而提高了高通量药物结构分析的速度.该平台实现了药物通用名、商品名和别名的检索,药物化学结构相似性搜索查看及其聚类分析可视化的功能.应用该系统进一步验证了与相同靶蛋白关联的药物,其化学结构更相似的结论.本文系统可通过http://122.70.220.99/bme的Drug and Disease访问.

  2. Can chemical structure predict reproductive toxicity?

    OpenAIRE

    Maslankiewicz L; Hulzebos EM; Vermeire TG; Muller JJA; Piersma AH; SEC

    2005-01-01

    Structure-Activity Relationships (SARs), including Quantitative SARs, are applied to the hazard assessment of chemicals. This need is all the more urgent considering the proposed new EU policy on chemicals in REACH, which stresses the need for non-animal testing. DEREKfW and the TSCA Chemical Category List of the New Chemicals Program of the US-EPA were chosen to predict reproductive toxicity for REACH purposes. DEREKfW is a software program predicting the toxicological properties using the l...

  3. Chemical durability and structural analysis of PbO–B2O3 glasses and testing for simulated radioactive wastes

    International Nuclear Information System (INIS)

    Graphical abstract: Secondary electron SEM images of lead borate glass including 80 mol% PbO before (top) and after chemical durability tests (bottom) - Abstract: Lead borate based glass formulations with high chemical durability and lower melting temperatures compared to the currently used glasses were developed as candidates for the vitrification of radioactive waste. Properties including chemical durability, glass transformation temperature, and melting temperature were analyzed. The chemical durability of PbO–B2O3 glasses with PbO contents ranging from 30 to 80 mol% was determined. An average dissolution rate of 0.2 g m−2 day−1 was obtained for the composition 80PbO⋅20B2O3. These glasses were studied under simulation conditions and showed good potential as a vitrification matrix for radioactive waste management. Clear vitrified waste products containing up to 30 mol% SrO and 25 mol% Cs2O could be obtained. Leaching rates are about hundred times higher in low PbO glasses compared to high PbO glasses. These results are encouraging since they open up new horizons in the development of low melting temperature lead borate glass for waste immobilization applications

  4. Protein Structure Determination Using Chemical Shifts

    DEFF Research Database (Denmark)

    Christensen, Anders Steen

    In this thesis, a protein structure determination using chemical shifts is presented. The method is implemented in the open source PHAISTOS protein simulation framework. The method combines sampling from a generative model with a coarse-grained force field and an energy function that includes...... chemical shifts. The method is benchmarked on folding simulations of five small proteins. In four cases the resulting structures are in excellent agreement with experimental data, the fifth case fail likely due to inaccuracies in the energy function. For the Chymotrypsin Inhibitor protein, a structure...

  5. Chemical structure and dynamics: Annual report 1993

    Energy Technology Data Exchange (ETDEWEB)

    Colson, S.D.

    1994-07-01

    The Chemical Structure and Dynamics program responds to the need for a fundamental, molecular-level understanding of chemistry at the wide variety of environmentally-important interfaces. The research program is built around the established relationship between structure, thermodynamics, and kinetics. This research effort continues to evolve into a program of rigorous studies of fundamental molecular processes in model systems (e.g., well-characterized surfaces, single-component solutions, clusters, and biological molecules), and studies of complex systems found in the environment. Experimental studies of molecular and supramolecular structures and thermodynamics are key to understanding the nature of matter, and lead to direct comparison with computational results. Kinetic and mechanistic measurements, combined with real-time dynamics measurements of atomic and molecular motions during chemical reactions, provide for a molecular-level description of chemical reactions. The anticipated results of this work are the achievement of a quantitative understanding of chemical processes at complex interfaces, the development of new techniques for the detection and measurement of species at such interfaces, and the interpretation and extrapolation of the observations in terms of models of interfacial chemistry. The Chemical Structure and Dynamics research program includes five areas described in detail in this report: Reaction mechanisms at solid interfaces; Solution and solution interfaces; Structure and dynamics of biological systems; Analytical methods development; and atmospheric chemistry. Extended abstracts are presented for 23 studies.

  6. Chemical structure and dynamics: Annual report 1996

    Energy Technology Data Exchange (ETDEWEB)

    Colson, S.D.; McDowell, R.S.

    1997-03-01

    The Chemical Structure and Dynamics (CS&D) program is a major component of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) developed by Pacific Northwest National Laboratory (PNNL) to provide a state-of-the-art collaborative facility for studies of chemical structure and dynamics. We respond to the need for a fundamental, molecular-level understanding of chemistry at a wide variety of environmentally important interfaces by (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage; and (3) developing state-of-the-art analytical methods for characterizing waste tanks and pollutant distributions, and for detecting and monitoring trace atmospheric species.

  7. Chemical structure and dynamics: Annual report 1996

    International Nuclear Information System (INIS)

    The Chemical Structure and Dynamics (CS ampersand D) program is a major component of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) developed by Pacific Northwest National Laboratory (PNNL) to provide a state-of-the-art collaborative facility for studies of chemical structure and dynamics. We respond to the need for a fundamental, molecular-level understanding of chemistry at a wide variety of environmentally important interfaces by (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage; and (3) developing state-of-the-art analytical methods for characterizing waste tanks and pollutant distributions, and for detecting and monitoring trace atmospheric species

  8. Chemical structure and dynamics. Annual report 1995

    Energy Technology Data Exchange (ETDEWEB)

    Colson, S.D.; McDowell, R.S.

    1996-05-01

    The Chemical Structure and Dynamics program is a major component of Pacific Northwest National Laboratory`s Environmental Molecular Sciences Laboratory (EMSL), providing a state-of-the-art collaborative facility for studies of chemical structure and dynamics. We respond to the need for a fundamental, molecular-level understanding of chemistry at a wide variety of environmentally important interfaces by (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage; and (3) developing state-of-the-art analytical methods for the characterization of waste tanks and pollutant distributions, and for detection and monitoring of trace atmospheric species.

  9. Annual Report 2000. Chemical Structure and Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Colson, Steven D.; McDowell, Robin S.

    2001-04-15

    This annual report describes the research and accomplishments of the Chemical Structure and Dynamics Program in the year 2000, one of six research programs at the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) - a multidisciplinary, national scientific user facility and research organization. The Chemical Structure and Dynamics (CS&D) program is meeting the need for a fundamental, molecular-level understanding by 1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; 2) developing a multidisciplinary capability for describing interfacial chemical processes relevant to environmental chemistry; and 3) developing state-of-the-art research and analytical methods for characterizing complex materials of the types found in natural and contaminated systems.

  10. Chemical Analysis of Single Cells

    Science.gov (United States)

    Borland, Laura M.; Kottegoda, Sumith; Phillips, K. Scott; Allbritton, Nancy L.

    2008-07-01

    Chemical analysis of single cells requires methods for quickly and quantitatively detecting a diverse array of analytes from extremely small volumes (femtoliters to nanoliters) with very high sensitivity and selectivity. Microelectrophoretic separations, using both traditional capillary electrophoresis and emerging microfluidic methods, are well suited for handling the unique size of single cells and limited numbers of intracellular molecules. Numerous analytes, ranging from small molecules such as amino acids and neurotransmitters to large proteins and subcellular organelles, have been quantified in single cells using microelectrophoretic separation techniques. Microseparation techniques, coupled to varying detection schemes including absorbance and fluorescence detection, electrochemical detection, and mass spectrometry, have allowed researchers to examine a number of processes inside single cells. This review also touches on a promising direction in single cell cytometry: the development of microfluidics for integrated cellular manipulation, chemical processing, and separation of cellular contents.

  11. Assessment of chemical species of lead accumulated in tidemarks of human articular cartilage by X-ray absorption near-edge structure analysis

    Energy Technology Data Exchange (ETDEWEB)

    Meirer, Florian [Atominstitut, Vienna University of Technology, 1020 Wien (Austria); MiNALab, CMM-Irst, Fondazione Bruno Kessler, Via Sommarive 18, 38123 Trento (Italy); Pemmer, Bernhard, E-mail: bpemmer@ati.ac.at [Atominstitut, Vienna University of Technology, 1020 Wien (Austria); Pepponi, Giancarlo [MiNALab, CMM-Irst, Fondazione Bruno Kessler, Via Sommarive 18, 38123 Trento (Italy); Zoeger, Norbert; Wobrauschek, Peter [Atominstitut, Vienna University of Technology, 1020 Wien (Austria); Sprio, Simone; Tampieri, Anna [Istituto di Scienza e Tecnologia dei Materiali Ceramici CNR, Faenca (Italy); Goettlicher, Joerg; Steininger, Ralph; Mangold, Stefan [Institute for Synchrotron Radiation, Karlsruhe Institute of Technology, Campus South, 76344 Eggenstein-Leopoldshafen (Germany); Roschger, Paul [Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 4th Medical Department, Hanusch Hospital, Vienna (Austria); Berzlanovich, Andrea [Department of Forensic Medicine, Medical University of Vienna, A-1090 Vienna (Austria); Hofstaetter, Jochen G. [Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 4th Medical Department, Hanusch Hospital, Vienna (Austria); Department of Orthopaedics, Vienna General Hospital, Medical University of Vienna, A-1090 Vienna (Austria); Streli, Christina [Atominstitut, Vienna University of Technology, 1020 Wien (Austria)

    2011-03-01

    Lead is a toxic trace element that shows a highly specific accumulation in the transition zone between calcified and non-calcified articular cartilage, the so-called ‘tidemark’. Excellent agreement has been found between XANES spectra of synthetic Pb-doped carbonated hydroxyapatite and spectra obtained in the tidemark region and trabecular bone of normal human samples, confirming that in both tissues Pb is incorporated into the hydroxyapatite crystal structure of bone. During this study the µ-XANES set-up at the SUL-X beamline at ANKA was tested and has proven to be well suited for speciation of lead in human mineralized tissue samples. A highly specific accumulation of the toxic element lead was recently measured in the transition zone between non-calcified and calcified normal human articular cartilage. This transition zone, the so-called ‘tidemark’, is considered to be an active calcification front of great clinical importance. However, little is known about the mechanisms of accumulation and the chemical form of Pb in calcified cartilage and bone. Using spatially resolved X-ray absorption near-edge structure analysis (µ-XANES) at the Pb L{sub 3}-edge, the chemical state of Pb in the osteochondral region was investigated. The feasibility of the µ-XANES set-up at the SUL-X beamline (ANKA synchrotron light source) was tested and confirmed by comparing XANES spectra of bulk Pb-reference compounds recorded at both the XAS and the SUL-X beamline at ANKA. The µ-XANES set-up was then used to investigate the tidemark region of human bone (two patella samples and one femoral head sample). The spectra recorded at the tidemark and at the trabecular bone were found to be highly correlated with the spectra of synthetic Pb-doped carbonated hydroxyapatite, suggesting that in both of these very different tissues Pb is incorporated into the hydroxyapatite structure.

  12. Assessment of chemical species of lead accumulated in tidemarks of human articular cartilage by X-ray absorption near-edge structure analysis

    International Nuclear Information System (INIS)

    Lead is a toxic trace element that shows a highly specific accumulation in the transition zone between calcified and non-calcified articular cartilage, the so-called ‘tidemark’. Excellent agreement has been found between XANES spectra of synthetic Pb-doped carbonated hydroxyapatite and spectra obtained in the tidemark region and trabecular bone of normal human samples, confirming that in both tissues Pb is incorporated into the hydroxyapatite crystal structure of bone. During this study the µ-XANES set-up at the SUL-X beamline at ANKA was tested and has proven to be well suited for speciation of lead in human mineralized tissue samples. A highly specific accumulation of the toxic element lead was recently measured in the transition zone between non-calcified and calcified normal human articular cartilage. This transition zone, the so-called ‘tidemark’, is considered to be an active calcification front of great clinical importance. However, little is known about the mechanisms of accumulation and the chemical form of Pb in calcified cartilage and bone. Using spatially resolved X-ray absorption near-edge structure analysis (µ-XANES) at the Pb L3-edge, the chemical state of Pb in the osteochondral region was investigated. The feasibility of the µ-XANES set-up at the SUL-X beamline (ANKA synchrotron light source) was tested and confirmed by comparing XANES spectra of bulk Pb-reference compounds recorded at both the XAS and the SUL-X beamline at ANKA. The µ-XANES set-up was then used to investigate the tidemark region of human bone (two patella samples and one femoral head sample). The spectra recorded at the tidemark and at the trabecular bone were found to be highly correlated with the spectra of synthetic Pb-doped carbonated hydroxyapatite, suggesting that in both of these very different tissues Pb is incorporated into the hydroxyapatite structure

  13. In Situ XPS Chemical Analysis of MnSiO3 Copper Diffusion Barrier Layer Formation and Simultaneous Fabrication of Metal Oxide Semiconductor Electrical Test MOS Structures.

    Science.gov (United States)

    Byrne, Conor; Brennan, Barry; McCoy, Anthony P; Bogan, Justin; Brady, Anita; Hughes, Greg

    2016-02-01

    Copper/SiO2/Si metal-oxide-semiconductor (MOS) devices both with and without a MnSiO3 barrier layer at the Cu/SiO2 interface have been fabricated in an ultrahigh vacuum X-ray photoelectron spectroscopy (XPS) system, which allows interface chemical characterization of the barrier formation process to be directly correlated with electrical testing of barrier layer effectiveness. Capacitance voltage (CV) analysis, before and after tube furnace anneals of the fabricated MOS structures showed that the presence of the MnSiO3 barrier layer significantly improved electric stability of the device structures. Evidence of improved adhesion of the deposited copper layer to the MnSiO3 surface compared to the clean SiO2 surface was apparent both from tape tests and while probing the samples during electrical testing. Secondary ion mass spectroscopy (SIMS) depth profiling measurements of the MOS test structures reveal distinct differences of copper diffusion into the SiO2 dielectric layers following the thermal anneal depending on the presence of the MnSiO3 barrier layer. PMID:26732185

  14. The PubChem chemical structure sketcher

    Directory of Open Access Journals (Sweden)

    Ihlenfeldt Wolf D

    2009-12-01

    Full Text Available Abstract PubChem is an important public, Web-based information source for chemical and bioactivity information. In order to provide convenient structure search methods on compounds stored in this database, one mandatory component is a Web-based drawing tool for interactive sketching of chemical query structures. Web-enabled chemical structure sketchers are not new, being in existence for years; however, solutions available rely on complex technology like Java applets or platform-dependent plug-ins. Due to general policy and support incident rate considerations, Java-based or platform-specific sketchers cannot be deployed as a part of public NCBI Web services. Our solution: a chemical structure sketching tool based exclusively on CGI server processing, client-side JavaScript functions, and image sequence streaming. The PubChem structure editor does not require the presence of any specific runtime support libraries or browser configurations on the client. It is completely platform-independent and verified to work on all major Web browsers, including older ones without support for Web2.0 JavaScript objects.

  15. The hierarchical structure of chemical engineering

    Institute of Scientific and Technical Information of China (English)

    Mooson KWAUK

    2007-01-01

    Around the turn of the present century, scholars began to recognize chemical engineering as a complex system, and have been searching for a convenient point of entry for refreshing its knowledge base. From our study of the dynamic structures of dispersed particles in fluidization and the resulting multi-scale method, we have been attempting to extend our findings to structures prevailing in other multiphase systems as well as in the burgeoning industries producing functional materials. Chemical engineering itself is hierarchically structured. Besides structures based on space and time, such hierarchy could be built from ChE history scaled according to science content, or from ChE operation according to the expenditure of manpower and capital investment.

  16. ANALYSIS OF DEPENDENCE OF THE FLOW TEMPERATURE OF THE PLASTICIZED POLYMER ON THE CHEMICAL STRUCTURE AND CONCENTRATION OF THE POLYMER AND THE PLASTICIZER

    Directory of Open Access Journals (Sweden)

    Askadskiy Andrey Aleksandrovich

    2012-10-01

    Full Text Available Polymeric materials are widely used in construction. The properties of polymeric construction materials vary to a substantial extent; their durability, thermal stability, frost resistance, waterproof and dielectric properties are particularly pronounced. Their properties serve as the drivers of the high market demand for these products. These materials are applied as finishing materials, molded sanitary engineering products and effective thermal insulation and water proofing materials. The authors analyze the influence of the chemical structure and structural features of polymers on their properties. The authors consider flow and vitrification temperatures of polymers. These temperatures determine the parameters of polymeric products, including those important for the construction process. The analysis of influence of concentration of the plasticizer on the vitrification temperature is based on the two basic theories. In accordance with the first one, reduction of the vitrification temperature is proportionate to the molar fraction of the injected plasticizer. According to the second concept, reduction of the vitrification temperature is proportionate to the volume fraction of the injected solvent. Dependencies of the flow temperature on the molecular weight and the molar fraction of the plasticizer are derived for PVC. As an example, two plasticizers were considered, including dibutyl sebacate and dioctylftalatalate. The basic parameters of all mixtures were calculated through the employment of "Cascade" software programme (A.N. Nesmeyanov Institute of Organoelemental Connections, Russian Academy of Sciences.

  17. Analysis of molecular electronic structure of imidazole- and benzimidazole-based inhibitors: A simple recipe for qualitative estimation of chemical hardness

    Energy Technology Data Exchange (ETDEWEB)

    Kovacevic, Natasa [Department of Physical and Organic Chemistry, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Kokalj, Anton, E-mail: tone.kokalj@ijs.s [Department of Physical and Organic Chemistry, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2011-03-15

    Research highlights: {yields} Electronic structure of imidazole and benzimidazole type corrosion inhibitors is assessed by quantum chemical calculations. {yields} Simple recipe for estimating chemical hardness trend of chemically similar inhibitor molecules is presented. {yields} Effect of various substituents on the molecular electronic structure and solvation free energy is explained. {yields} Possible implications to adsorption and consequent inhibition of corrosion are discussed. - Abstract: The effect of methyl, phenyl, and mercapto substituents on electronic structure of imidazole type inhibitors was characterized by density-functional-theory calculations. The most coherent trend is observed for chemical hardness. It is demonstrated that, in general, larger molecules are chemically softer provided they belong to the same chemical type. The electronegativity is reduced by methyl and mercapto substituents and increased by phenyl substituent. It is further shown that phenyl substituent reduces the solvation free energy thus increasing the relative tendency of the molecule to get adsorbed on the surface, which may contribute to the increased inhibition effectiveness against corrosion of copper.

  18. Chemical Structure and Dynamics annual report 1997

    Energy Technology Data Exchange (ETDEWEB)

    Colson, S.D.; McDowell, R.S.

    1998-03-01

    The Chemical Structure and Dynamics (CS and D) program is a major component of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), developed by Pacific Northwest National Laboratory (PNNL) to provide a state-of-the-art collaborative facility for studies of chemical structure and dynamics. The authors respond to the need for a fundamental, molecular level understanding of chemistry at a wide variety of environmentally important interfaces by: (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage; and (3) developing state-of-the-art analytical methods for characterizing complex materials of the types found in stored wastes and contaminated soils, and for detecting and monitoring trace atmospheric species. The focus of the research is defined primarily by DOE`s environmental problems: fate and transport of contaminants in the subsurface environment, processing and storage of waste materials, cellular effects of chemical and radiological insult, and atmospheric chemistry as it relates to air quality and global change. Twenty-seven projects are described under the following topical sections: Reaction mechanisms at interfaces; High-energy processes at environmental interfaces; Cluster models of the condensed phase; and Miscellaneous.

  19. Chemical Structure and Dynamics annual report 1997

    International Nuclear Information System (INIS)

    The Chemical Structure and Dynamics (CS and D) program is a major component of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), developed by Pacific Northwest National Laboratory (PNNL) to provide a state-of-the-art collaborative facility for studies of chemical structure and dynamics. The authors respond to the need for a fundamental, molecular level understanding of chemistry at a wide variety of environmentally important interfaces by: (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage; and (3) developing state-of-the-art analytical methods for characterizing complex materials of the types found in stored wastes and contaminated soils, and for detecting and monitoring trace atmospheric species. The focus of the research is defined primarily by DOE's environmental problems: fate and transport of contaminants in the subsurface environment, processing and storage of waste materials, cellular effects of chemical and radiological insult, and atmospheric chemistry as it relates to air quality and global change. Twenty-seven projects are described under the following topical sections: Reaction mechanisms at interfaces; High-energy processes at environmental interfaces; Cluster models of the condensed phase; and Miscellaneous

  20. Chemical effects in the mine structure

    International Nuclear Information System (INIS)

    The main objective of the workshop was to bring together, and get talking to each other, long-term safety modellers, geochemical modellers and experimenters working in the field of chemical effects, and to give an insight into their respective activity areas and problem constellations. Lectures on the following subjects were given: modelling of chemical effects in long-term safety analysis; influence of brines; corrosion experiments; sorption experiments; actinide chemistry experiments; geochemical modelling; requirements of safety analyses and geochemical modelling. The workshop concluded with a detailed discussion of the subjects raised and of interdisciplinary aspects. (orig./DG)

  1. Annual Report 1998: Chemical Structure and Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    SD Colson; RS McDowell

    1999-05-10

    The Chemical Structure and Dynamics (CS&D) program is a major component of the William R. Wiley Environmental Molecular Sciences Labo- ratory (EMSL), developed by Pacific Northwest National Laboratory (PNNL) to provide a state-of- the-art collaborative facility for studies of chemical structure and dynamics. We respond to the need for a fundamental, molecular-level understanding of chemistry at a wide variety of environmentally important interfaces by (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interracial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in envi- ronmental chemistry and in nuclear waste proc- essing and storage; and (3) developing state-of- the-art analytical methods for characterizing com- plex materials of the types found in stored wastes and contaminated soils, and for detecting and monitoring trace atmospheric species. Our program aims at achieving a quantitative understanding of chemical reactions at interfaces and, more generally, in condensed media, compa- rable to that currently available for gas-phase reactions. This understanding will form the basis for the development of a priori theories for pre- dicting macroscopic chemical behavior in con- densed and heterogeneous media, which will add significantly to the value of field-scale envi- ronmental models, predictions of short- and long- term nuclear waste storage stabilities, and other areas related to the primary missions of the U.S. Department of Energy (DOE).

  2. Chemical structure and dynamics. Annual report 1994

    Energy Technology Data Exchange (ETDEWEB)

    Colson, S.D.

    1995-07-01

    The Chemical Structure and Dynamics program was organized as a major component of Pacific Northwest Laboratory`s Environmental and Molecular Sciences Laboratory (EMSL), a state-of-the-art collaborative facility for studies of chemical structure and dynamics. Our program responds to the need for a fundamental, molecular-level understanding of chemistry at the wide variety of environmentally important interfaces by (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces, and (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage. This research effort was initiated in 1989 and will continue to evolve over the next few years into a program of rigorous studies of fundamental molecular processes in model systems, such as well-characterized surfaces, single-component solutions, clusters, and biological molecules; and studies of complex systems found in the environment (multispecies, multiphase solutions; solid/liquid, liquid/liquid, and gas/surface interfaces; colloidal dispersions; ultrafine aerosols; and functioning biological systems). The success of this program will result in the achievement of a quantitative understanding of chemical reactions at interfaces, and more generally in condensed media, that is comparable to that currently available for gas-phase reactions. This understanding will form the basis for the development of a priori theories for predictions of macroscopic chemical behavior in condensed and heterogeneous media, adding significantly to the value of field-scale environmental models, the prediction of short- and long-term nuclear waste storage stabilities, and other problems related to the primary missions of the DOE.

  3. FTIR and XPS analysis of the changes in bamboo chemical structure decayed by white-rot and brown-rot fungi

    International Nuclear Information System (INIS)

    In order to investigate different types of decay mechanisms in bamboo (Phyllostachys edulis), the chemical structure and microstructure of bamboo samples decayed by P. chrysosporium (White-rot) and G. trabeum (Brown-rot) for 12 weeks were studied. The analysis methods include fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron spectroscopy (SEM). By using the SEM method, it was found that attacks to parenchyma cells and places near the inner skin of bamboo were the most frequent and the vessels were the primary paths for the spread of mycelium in the bamboo. FTIR and XPS results showed that the crystallinity (I1425/I896) of bamboo decreased after being decayed by these two fungi and the crystalline cellulose in bamboo was degraded. The white-rot P. chrysosporium had stronger degradability on lignin compared to hemicellulose and cellulose in bamboo. And the brown-rot G. trabeum had preferential degradability on hemicellulose fraction over cellulose and lignin. Oxidation and hydrolysis surface reactions occurred during the process of decay, but the reaction rates for cellulose and lignin were different.

  4. FTIR and XPS analysis of the changes in bamboo chemical structure decayed by white-rot and brown-rot fungi

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Guoqi [College of Engineering and Technology, Northeast Forestry University, Harbin 150040 (China); Wang, Lihai, E-mail: xu12nefu@sina.cn [College of Engineering and Technology, Northeast Forestry University, Harbin 150040 (China); Liu, Junliang [Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091 (China); Wu, Jinzhuo [College of Engineering and Technology, Northeast Forestry University, Harbin 150040 (China)

    2013-09-01

    In order to investigate different types of decay mechanisms in bamboo (Phyllostachys edulis), the chemical structure and microstructure of bamboo samples decayed by P. chrysosporium (White-rot) and G. trabeum (Brown-rot) for 12 weeks were studied. The analysis methods include fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron spectroscopy (SEM). By using the SEM method, it was found that attacks to parenchyma cells and places near the inner skin of bamboo were the most frequent and the vessels were the primary paths for the spread of mycelium in the bamboo. FTIR and XPS results showed that the crystallinity (I1425/I896) of bamboo decreased after being decayed by these two fungi and the crystalline cellulose in bamboo was degraded. The white-rot P. chrysosporium had stronger degradability on lignin compared to hemicellulose and cellulose in bamboo. And the brown-rot G. trabeum had preferential degradability on hemicellulose fraction over cellulose and lignin. Oxidation and hydrolysis surface reactions occurred during the process of decay, but the reaction rates for cellulose and lignin were different.

  5. Contact allergy to oak moss: search for sensitizing molecules using combined bioassay-guided chemical fractionation, GC-MS, and structure-activity relationship analysis.

    Science.gov (United States)

    Bernard, Guillaume; Giménez-Arnau, Elena; Rastogi, Suresh Chandra; Heydorn, Siri; Johansen, Jeanne Duus; Menné, Torkil; Goossens, An; Andersen, Klaus; Lepoittevin, Jean-Pierre

    2003-11-01

    In addition to pure synthetic fragrance materials several natural extracts are still in use in the perfume industry. Among them oak moss absolute, prepared from the lichen Evernia prunastri (L.) Arch., is considered a major contact sensitizer and is therefore included in the fragrance mix used for diagnosing perfume allergy. The process of preparing oak moss absolute has changed during recent years and, even though several potential sensitizers have been identified from former benzene extracts, its present constituents and their allergenic status are not clear. In the study reported here, we applied a method developed for the identification of contact allergens present in natural complex mixtures to oak moss absolute. The method is based on the combination of bioassay-guided chemical fractionation, gas chromatography-mass spectrometry analysis and structure-activity relationship studies. Our first results showed that atranol and chloroatranol, formed by transesterification and decarboxylation of the lichen depsides, atranorin and chloroatranorin, during the preparation of oak moss absolute, are strong elicitants in most patients sensitized to oak moss. Methyl-beta-orcinol carboxylate, a depside degradation product and the most important monoaryl derivative of oak moss from an olfactory standpoint, was also found to elicit a reaction in most patients. PMID:13680271

  6. The hierarchical structure of chemical engineering

    Institute of Scientific and Technical Information of China (English)

    Mooson; KWAUK

    2007-01-01

    Around the turn of the present century,scholars began to recognize chemical engineering as a com-plex system,and have been searching for a convenient point of entry for refreshing its knowledge base.From our study of the dynamic structures of dispersed particles in fluidization and the resultingmulti-scale method,we have been attempting to extend our findings to structures prevailing in othermultiphase systems as well as in the burgeoning industries producing functional materials.Chemicalengineering itself is hierarchically structured.Besides structures based on space and time,such hier-archy could be built from ChE history scaled according to science content,or from ChE operation ac-cording to the expenditure of manpower and capital investment.

  7. Electronic structure, magnetic properties, and microstructural analysis of thiol-functionalized Au nanoparticles: role of chemical and structural parameters in the ferromagnetic behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, Estefania; Munoz-Marquez, Miguel A., E-mail: miguel.angel@icmse.csic.e [Instituto de Ciencia de Materiales de Sevilla (CSIC-US) (Spain); Fernandez-Pinel, Enrique; Crespo, Patricia; Hernando, Antonio [Instituto de Magnetismo Aplicado (UCM-ADIF-CSIC) (Spain); Fernandez, Asuncion [Instituto de Ciencia de Materiales de Sevilla (CSIC-US) (Spain)

    2008-12-15

    Gold nanoparticles (NPs) have been stabilized with a variety of thiol-containing molecules in order to change their chemical and physical properties; among the possible capping systems, alkane chains with different lengths, a carboxylic acid and a thiol-containing biomolecule (tiopronin) have been selected as protecting shells for the synthesized NPs; the NPs solubility in water or organic solvents is determined by the protecting molecule. A full microstructural characterization of these NPs is presented in the current research work. It has been shown that NPs capped with alkanethiol chains have a marked ferromagnetic behaviour which might also be dependent on the chain length. The simultaneous presence of Au-Au and Au-S bonds together with a reduced particle diameter, and the formation of an ordered monolayer protective shell, have proved to be key parameters for the ferromagnetic-like behaviour exhibited by thiol-functionalized gold NPs.

  8. Molecular structure, electronic properties, NLO, NBO analysis and spectroscopic characterization of Gabapentin with experimental (FT-IR and FT-Raman) techniques and quantum chemical calculations.

    Science.gov (United States)

    Sinha, Leena; Karabacak, Mehmet; Narayan, V; Cinar, Mehmet; Prasad, Onkar

    2013-05-15

    Gabapentin (GP), structurally related to the neurotransmitter GABA (gamma-aminobutyric acid), mimics the activity of GABA and is also widely used in neurology for the treatment of peripheral neuropathic pain. It exists in zwitterionic form in solid state. The present communication deals with the quantum chemical calculations of energies, geometrical structure and vibrational wavenumbers of GP using density functional (DFT/B3LYP) method with 6-311++G(d,p) basis set. In view of the fact that amino acids exist as zwitterions as well as in the neutral form depending on the environment (solvent, pH, etc.), molecular properties of both the zwitterionic and neutral form of GP have been analyzed. The fundamental vibrational wavenumbers as well as their intensities were calculated and compared with experimental FT-IR and FT-Raman spectra. The fundamental assignments were done on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. The electric dipole moment, polarizability and the first hyperpolarizability values of the GP have been calculated at the same level of theory and basis set. The nonlinear optical (NLO) behavior of zwitterionic and neutral form has been compared. Stability of the molecule arising from hyper-conjugative interactions and charge delocalization has been analyzed using natural bond orbital analysis. Ultraviolet-visible (UV-Vis) spectrum of the title molecule has also been calculated using TD-DFT method. The thermodynamic properties of both the zwitterionic and neutral form of GP at different temperatures have been calculated. PMID:23545435

  9. Molecular structure, electronic properties, NLO, NBO analysis and spectroscopic characterization of Gabapentin with experimental (FT-IR and FT-Raman) techniques and quantum chemical calculations

    Science.gov (United States)

    Sinha, Leena; Karabacak, Mehmet; Narayan, V.; Cinar, Mehmet; Prasad, Onkar

    2013-05-01

    Gabapentin (GP), structurally related to the neurotransmitter GABA (gamma-aminobutyric acid), mimics the activity of GABA and is also widely used in neurology for the treatment of peripheral neuropathic pain. It exists in zwitterionic form in solid state. The present communication deals with the quantum chemical calculations of energies, geometrical structure and vibrational wavenumbers of GP using density functional (DFT/B3LYP) method with 6-311++G(d,p) basis set. In view of the fact that amino acids exist as zwitterions as well as in the neutral form depending on the environment (solvent, pH, etc.), molecular properties of both the zwitterionic and neutral form of GP have been analyzed. The fundamental vibrational wavenumbers as well as their intensities were calculated and compared with experimental FT-IR and FT-Raman spectra. The fundamental assignments were done on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. The electric dipole moment, polarizability and the first hyperpolarizability values of the GP have been calculated at the same level of theory and basis set. The nonlinear optical (NLO) behavior of zwitterionic and neutral form has been compared. Stability of the molecule arising from hyper-conjugative interactions and charge delocalization has been analyzed using natural bond orbital analysis. Ultraviolet-visible (UV-Vis) spectrum of the title molecule has also been calculated using TD-DFT method. The thermodynamic properties of both the zwitterionic and neutral form of GP at different temperatures have been calculated.

  10. CHANGES IN THE CHEMICAL STRUCTURE OF THERMALLY TREATED WOOD

    Directory of Open Access Journals (Sweden)

    Birol Uner

    2010-07-01

    Full Text Available Changes in the chemical structure of hornbeam and uludag fir woods during thermal treatment were investigated at three temperatures (170, 190, and 210 oC and three durations (4, 8, and 12 hours. After thermal treatment, the extents of degradation in the chemical structure of the samples were determined, and the effects on the chemical composition of hornbeam wood and uludag fir wood were investigated. The data obtained were analyzed using variance analysis, and Tukey’s test was used to determine the changes in the chemical structure of uludag fir and hornbeam woods. The results showed that heating wood permanently changes several of its chemical structures and that the changes are mainly caused by thermal degradation of wood polymers. It was found that decreasing of the cellulose and holocelluloses ratio had a favorable effect on the interaction of the wood with moisture. According to the obtained results, hornbeam wood is affected more than uludag fir wood. For each wood, the maximum decreases of holocellulose and α-cellulose were found at 210oC for 12 hours, and the maximum increase of lignin occurred at the same treatment combination.

  11. The chemical bond structure and dynamics

    CERN Document Server

    Zewail, Ahmed

    1992-01-01

    This inspired book by some of the most influential scientists of our time--including six Nobel laureates--chronicles our emerging understanding of the chemical bond through the last nine decades and into the future. From Pauling's early structural work using x-ray and electron diffraction to Zewail's femtosecond lasers that probe molecular dynamics in real time; from Crick's molecular biology to Rich's molecular recognition, this book explores a rich tradition of scientific heritage and accomplishment. The perspectives given by Pauling, Perutz, Rich, Crick, Porter, Polanyi, Herschbach, Zewail,

  12. Quantum chemical investigation for structures and bonding analysis of molybdenum tetracarbonyl complexes with N-heterocyclic carbene and analogues: helpful information for plant biology research

    OpenAIRE

    Nguyen, Thi Ai Nhung; Huynh, Thi Phuong Loan; Pham Van, Tat

    2015-01-01

    Quantum chemical calculations at the gradient-corrected (BP86) density-functional calculations with various basis sets (SVP, TZVPP) have been carried out for Mo(CO)4 complexes of Nheterocyclic carbene and analogues-NHEMe (called tetrylenes) with E = C, Si, Ge, Sn, Pb. The equilibrium structures of complexes [Mo(CO)4-NHEMe] (Mo4-NHEMe) exhibit an interesting trend which the lightest adduct Mo4-NHCMe has a trigonal bipyramidal coordination mode where the ligand NHCMe occupies an equatorial posi...

  13. Bond-length analysis of the omega structure in Ti,Zr,Hf and their alloys: experimental data, new correlations and implications for chemical bonding models

    Energy Technology Data Exchange (ETDEWEB)

    Grad, G.B.; Benites, G.M. [Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche; Aurelio, G. [Departamento de Fisica, Universidad del Comahue, 8300, Neuquen (Argentina); Fernandez Guillermet, A. [Centro Atomico Bariloche, 8400, San Carlos de Bariloche (Argentina)

    1999-12-15

    An analysis is performed of the experimental information on the key interatomic distances (IDs) of the AlB{sub 2} type structure, the so-called omega ({omega}) phase in Ti and Zr, as well as in Ti-V and Zr-Nb alloys. Various remarkable correlations are found between these IDs and standard measures of the atomic size, and with Pauling's bond-lengths. These observations are discussed in the light of the phenomenological bonding pictures of the {omega} structure, and with our recent ab initio calculations of the electronic structure of this phase. (orig.)

  14. Optical MEMS for chemical analysis and biomedicine

    CERN Document Server

    Jiang, Hongrui

    2016-01-01

    This book describes the current state of optical MEMS in chemical and biomedical analysis and brings together current trends and highlights topics representing the most exciting progress in recent years in the field.

  15. Characterization of iron-phosphate-silicate chemical garden structures.

    Science.gov (United States)

    Barge, Laura M; Doloboff, Ivria J; White, Lauren M; Stucky, Galen D; Russell, Michael J; Kanik, Isik

    2012-02-28

    Chemical gardens form when ferrous chloride hydrate seed crystals are added or concentrated solutions are injected into solutions of sodium silicate and potassium phosphate. Various precipitation morphologies are observed depending on silicate and phosphate concentrations, including hollow plumes, bulbs, and tubes. The growth of precipitates is controlled by the internal osmotic pressure, fluid buoyancy, and membrane strength. Additionally, rapid bubble-led growth is observed when silicate concentrations are high. ESEM/EDX analysis confirms compositional gradients within the membranes, and voltage measurements across the membranes during growth show a final potential of around 150-200 mV, indicating that electrochemical gradients are maintained across the membranes as growth proceeds. The characterization of chemical gardens formed with iron, silicate, and phosphate, three important components of an early earth prebiotic hydrothermal system, can help us understand the properties of analogous structures that likely formed at submarine alkaline hydrothermal vents in the Hadean-structures offering themselves as the hatchery of life.

  16. Chemical syntheses of inulin and levan structures.

    Science.gov (United States)

    Oscarson, Stefan; Sehgelmeble, Fernando W

    2002-11-29

    A fructofuranosyl thiglycoside donor, ethyl 6-O-acetyl-3-O-benzyl-1,4-O-(1,1,3,3-tetraisopropyldisiloxane-1,3-diyl)-2-thio-beta-D-fructofuranoside (11), designed to yield stereospecifically beta-linkages and also to allow subsequent elongation in the 6- and/or 1-positions, was prepared and used in syntheses of levan and inulin structures. DMTST-promoted glycosylation between 11 (1.3 mol equiv) and methyl beta-D-fructofuranoside 6-OH and 1-OH acceptors (3 and 6) gave stereospecifically the protected methyl levanobioside 12 and inulinobioside 17 in excellent yields (80 and 86%), respectively. Protecting group manipulations on these afforded new disaccharide 6'-OH and 1'-OH acceptors (13 and 19), which were coupled again with donor 11 (1.0 mol equiv) to yield methyl levanotrioside 14 and inulinotrioside 20 in high yields, 65 and 67%, respectively. These were transformed into new acceptors and also fully deprotected to afford the methyl glycosides of levanotriose and inulinotriose, all structures that have earlier not been accessible by chemical synthesis. PMID:12444625

  17. Oxygen-aromatic contacts in intra-strand base pairs: analysis of high-resolution DNA crystal structures and quantum chemical calculations.

    Science.gov (United States)

    Jain, Alok; Krishna Deepak, R N V; Sankararamakrishnan, Ramasubbu

    2014-07-01

    Three-dimensional structures of biomolecules are stabilized by a large number of non-covalent interactions and some of them such as van der Waals, electrostatic and hydrogen bond interactions are well characterized. Delocalized π-electron clouds of aromatic residues are known to be involved in cation-π, CH-π, OH-π and π-π interactions. In proteins, many examples have been found in which the backbone carbonyl oxygen of one residue makes close contact with the aromatic center of aromatic residues. Quantum chemical calculations suggest that such contacts may provide stability to the protein secondary structures. In this study, we have systematically analyzed the experimentally determined high-resolution DNA crystal structures and identified 91 examples in which the aromatic center of one base is in close contact (interactions between the bases in base pairs with oxygen-aromatic contacts are energetically favorable. Decomposition of interaction energies indicates that dispersion forces are the major cause for energetically stable interaction in these base pairs. We speculate that oxygen-aromatic contacts in intra-strand base pairs in a DNA structure may have biological significance. PMID:24816369

  18. MALDI-TOF MS Analysis of Proanthocyanidins in Two Lowland Tropical Forest Species of Cecropia: A First Look at Their Chemical Structures

    Directory of Open Access Journals (Sweden)

    Alex Van Huynh

    2014-09-01

    Full Text Available The structural chemistry of proanthocyanidin molecules has been investigated in temperate zone plants, but few studies have been done with plants of the Amazonian lowland tropical wet forests where herbivore pressure is more extensive and diverse. Using MALDI-TOF mass spectrometry, we report unique properties of the proanthocyanidin structural chemistry in two neotropical Cecropia species, C. polystachya, a myrmecophyte with mutualistic ants, and C. sciadophylla, a non-myrmecophyte lacking mutualistic ants. Our preliminary data suggests the presence of reportedly uncommon propelargonidin subunits in a majority of proanthocyanidin oligomers. The presence of 3-O-gallate proanthocyanidin monomers was also detected in the mass spectra of both species. Unlike other studies that have examined species growing at higher latitudes, oligomers composed of procyanidin, propelargonidin, and their 3-O-gallates were present in both Cecropia species while the presence of oligomers containing prodelphinidin units were absent or at lower levels. These distinctive features may suggest that proanthocyanidins in some tropical plant species may be an untapped source of proanthocyanidin structural complexity that warrants further investigation. Several differences between spectra of the two Cecropia species could also point to the presence of anti-herbivore defense tradeoffs between chemical defense quality and biotic defense between the two species.

  19. Structural analysis for Diagnosis

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Blanke, M.

    2001-01-01

    Aiming at design of algorithms for fault diagnosis, structural analysis of systems offers concise yet easy overall analysis. Graph-based matching, which is the essential technique to obtain redundant information for diagnosis, is re-considered in this paper. Matching is re-formulated as a problem...

  20. 40 CFR 761.253 - Chemical analysis.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Chemical analysis. 761.253 Section 761.253 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT... analysis. (a) Extract PCBs from the standard wipe sample collection medium and clean-up the extracted...

  1. Structure analysis and spectroscopic characterization of 2-Fluoro-3-Methylpyridine-5-Boronic Acid with experimental (FT-IR, Raman, NMR and XRD) techniques and quantum chemical calculations

    Science.gov (United States)

    Alver, Özgür; Dikmen, Gökhan

    2016-03-01

    Possible stable conformers, geometrical molecular structures, vibrational properties as well as band assignments, nuclear magnetic shielding tensors of 2-Fluoro-3-Methylpyridine-5-Boronic Acid (2F3MP5BA) were studied experimentally and theoretically using FT-IR, Raman, (CP/MAS) NMR and XRD spectroscopic methods. FT-IR and Raman spectra were evaluated in the region of 3500-400 cm-1, and 3200-400 cm-1, respectively. The optimized geometric structures, vibrational wavenumbers and nuclear magnetic shielding tensors were examined using Becke-3-Lee-Yang-Parr (B3LYP) hybrid density functional theory method with 6-311++G(d, p) basis set. 1H, 13C NMR chemical shifts were calculated using the gauge invariant atomic orbital (GIAO) method. 1H, 13C, APT and HETCOR NMR experiments of title molecule were carried out in DMSO solution. 13C CP/MAS NMR measurement was done with 4 mm zirconium rotor and glycine was used as an external standard. Single crystal of 2F3MP5BA was also prepared for XRD measurements. Assignments of vibrational wavenumbers were also strengthened by calculating the total energy distribution (TED) values using scaled quantum mechanical (SQM) method.

  2. Chemical analysis of high purity graphite

    International Nuclear Information System (INIS)

    The Sub-Committee on Chemical Analysis of Graphite was organized in April 1989, under the Committee on Chemical Analysis of Nuclear Fuels and Reactor Materials, JAERI. The Sub-Committee carried out collaborative analyses among eleven participating laboratories for the certification of the Certified Reference Materials (CRMs), JAERI-G5 and G6, after developing and evaluating analytical methods during the period of September 1989 to March 1992. The certified values were given for ash, boron and silicon in the CRM based on the collaborative analysis. The values for ten elements (Al, Ca, Cr, Fe, Mg, Mo, Ni, Sr, Ti, V) were not certified, but given for information. Preparation, homogeneity testing and chemical analyses for certification of reference materials were described in this paper. (author) 52 refs

  3. Gradient Bundle Analysis: A Full Topological Approach to Chemical Bonding

    CERN Document Server

    Morgenstern, Amanda

    2016-01-01

    The "chemical bond" is a central concept in molecular sciences, but there is no consensus as to what a bond actually is. Therefore, a variety of bonding models have been developed, each defining the structure of molecules in a different manner with the goal of explaining and predicting chemical properties. This thesis describes the initial development of gradient bundle analysis (GBA), a chemical bonding model that creates a high resolution picture of chemical interactions within the charge density framework. GBA is based on concepts from the quantum theory of atoms in molecules (QTAIM), but uses a more complete picture of the topology and geometry of the electron charge density to understand and predict bonding interactions. Gradient bundles are defined as volumes bounded by zero-flux surfaces (ZFSs) in the gradient of the charge density with well-defined energies. The structure of gradient bundles provides an avenue for detecting the locations of valence electrons, which correspond to reactive regions in a ...

  4. Spectroscopic chemical analysis methods and apparatus

    Science.gov (United States)

    Hug, William F. (Inventor); Reid, Ray D. (Inventor); Bhartia, Rohit (Inventor)

    2013-01-01

    Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

  5. Service activities of chemical analysis division

    International Nuclear Information System (INIS)

    Progress of the Division during the year of 1988 was described on the service activities for various R and D projects carrying out in the Institute, for the fuel fabrication and conversion plant, and for the post-irradiation examination facility. Relevant analytical methodologies developed for the chemical analysis of an irradiated fuel, safeguards chemical analysis, and pool water monitoring were included such as chromatographic separation of lanthanides, polarographic determination of dissolved oxygen in water, and automation on potentiometric titration of uranium. Some of the laboratory manuals revised were also included in this progress report. (Author)

  6. Quantum chemical investigation on the structural and electronic properties of α-, β-, and γ-cyclodextrin complexes: DFT and QTAIM analysis

    Science.gov (United States)

    Dehestani, M.; Pourestarabadi, S.; Zeidabadinejad, L.

    2016-06-01

    To characterize the structural, thermochemical and electronic aspects in complexes of leucine, vanillin and mechlorethamine with α-, β-, and γ-cyclodextrins (CDs), a density functional theory (DFT) study has been conducted in combination with quantum theory of atoms in molecules (QTAIM) analysis. The QTAIM method has been utilized to explore the nature of various possible interactions between leucine, vanillin and mechlorethamine with CDs in terms of bond critical points (BCPs). HOMO and LUMO and atomic charges studies show charge transfer occurs between drugs and cyclodextrins. This behavior has been also investigated via QTAIM charge analysis. On the other hand, based on QTAIM electronic energy indicators we have discussed electrostatic character of interactions between vanillin, leucine and mechlorethamine with inner surface CDs in the coordination sphere.

  7. Rutherford Backscattering Spectrometry Analysis and Structural Properties of ZnxPb1-xS Thin Films Deposited by Chemical Spray Pyrolysis

    Directory of Open Access Journals (Sweden)

    Abiodun E. Adeoye

    2015-01-01

    Full Text Available Zinc lead sulphide ternary thin films were prepared by chemical spray pyrolysis on soda lime glass substrates using zinc acetate, lead acetate, and thiourea sources precursor. The films were characterized using Rutherford backscattering (RBS spectrometry, energy dispersive X-ray (EDX spectroscopy, scanning electron microscopy (SEM, and X-ray diffractometry (XRD. RBS studies revealed variation in thickness and stoichiometry of the films with respect to compositional substitution between Zn and Pb, thereby giving effective composition ZnxPb1-xS, where x=0, 0.035, 0.069, 0.109, 0.176, and 0.217. Film thickness obtained by length conversion ranged from 81.02 nm to 90.03 nm. Microstructural analyses also indicated that the growth and particle distribution of the films were uniform across substrate’s surface. Diffraction studies showed that the films possess FCC crystalline structure. Crystallite size reduced from 14.28 to 9.8 nm with increase in Zn2+ in the ZnxPb1-xS samples.

  8. Structural analysis of DAEs

    DEFF Research Database (Denmark)

    Poulsen, Mikael Zebbelin

    2002-01-01

    , by the implementation of the Simpy tool box. This is an object oriented system implemented in the Python language. It can be used for analysis of DAEs, ODEs and non-linear equation and uses e.g. symbolic representations of expressions and equations. The presentations of theory and algorithms for structural index...

  9. Molecular structure and vibrational spectroscopic analysis of an antiplatelet drug; clopidogrel hydrogen sulphate (form 2) - A combined experimental and quantum chemical approach

    Science.gov (United States)

    Srivastava, Anubha; Mishra, Soni; Tandon, Poonam; Patel, Sarasvatkumar; Ayala, A. P.; Bansal, A. K.; Siesler, H. W.

    2010-02-01

    Clopidogrel hydrogen sulphate which belongs to a class of medicine called antiplatelet drugs. Chemically it is methyl (+)-(S)-α-(2-chlorophenyl)-4,5,6,7-tetrahydrothieno [3,2- c] pyridine-5-acetate hydrogen sulphate having the empirical formula C 16H 17ClNO 2S.HSO 4 and molecular mass 321.82 g/mol. The present study is confined to vibrational spectroscopy of the polymorph identified as form 2 of the clopidogrel hydrogen sulphate. The vibrational analysis of clopidogrel hydrogen sulphate salt (form 2) considering separately the two counterions has been performed. We also report a theoretical and experimental study of the molecular conformation and vibrational dynamics of the independent moieties of the clopidogrel hydrogen sulphate salt. The equilibrium geometry, harmonic vibrational frequencies, infrared intensities and activities of Raman scattering were calculated by ab initio Hartree-Fock and density functional theory employing B3LYP with complete relaxation in the potential energy surface using 6-311++G(d,p) basis set. The calculated wavenumbers after a proper scaling show a very good agreement with the observed values. A complete vibrational assignment is provided for the observed Raman and infrared spectra of clopidogrel hydrogen sulphate form 2.

  10. Chemical composition and structure of sapropelitic coals

    Energy Technology Data Exchange (ETDEWEB)

    Bodoev, N.V. [Inst. of Carbon Material Chemistry, RAS, Kemerovo (Russian Federation); Guet, J.M. [Centre de Recherche sur la Matiere Divisee, Orleans (France); Gruber, R. [Lab. de Thermodynamique et d`Analyse Chimique, Univ. de Metz (France)

    1997-12-31

    Sapropelitic coals of low rank coalification stages were examined using solid state {sup 13}C n.m.r. with cross polarization and magic angle spinning techniques, FT-i.r. spectroscopy and X-ray diffraction (XRD) methods. The FT-i.r., and using solid state {sup 13}C n.m.r. spectra showed that the main constituents of low rank sapropelitic coals are aliphatic chains with carbonyl and carboxylic groups. The XRD analysis of low rank sapropelitic coals has shown very great differences from humic coals. The method of function of radial distribution of atoms (FRDA) was applied to low rank sapropelitic coals. The maxima at 0.5 and 1 nm of FRDA curves of these coals were established, indicating the parallel orientation of aliphatic chains in sapropelitic coals. The sapropelitic structure is probably determined by preservation of microorganisms and algal cell membranes, because it is known that the aliphatic parts of fatty acids of cell membranes have a parallel orientation. (orig.)

  11. Aromatic rings in chemical and biological recognition: energetics and structures.

    Science.gov (United States)

    Salonen, Laura M; Ellermann, Manuel; Diederich, François

    2011-05-16

    This review describes a multidimensional treatment of molecular recognition phenomena involving aromatic rings in chemical and biological systems. It summarizes new results reported since the appearance of an earlier review in 2003 in host-guest chemistry, biological affinity assays and biostructural analysis, data base mining in the Cambridge Structural Database (CSD) and the Protein Data Bank (PDB), and advanced computational studies. Topics addressed are arene-arene, perfluoroarene-arene, S⋅⋅⋅aromatic, cation-π, and anion-π interactions, as well as hydrogen bonding to π systems. The generated knowledge benefits, in particular, structure-based hit-to-lead development and lead optimization both in the pharmaceutical and in the crop protection industry. It equally facilitates the development of new advanced materials and supramolecular systems, and should inspire further utilization of interactions with aromatic rings to control the stereochemical outcome of synthetic transformations. PMID:21538733

  12. Automated extraction of chemical structure information from digital raster images

    Directory of Open Access Journals (Sweden)

    Shedden Kerby A

    2009-02-01

    Full Text Available Abstract Background To search for chemical structures in research articles, diagrams or text representing molecules need to be translated to a standard chemical file format compatible with cheminformatic search engines. Nevertheless, chemical information contained in research articles is often referenced as analog diagrams of chemical structures embedded in digital raster images. To automate analog-to-digital conversion of chemical structure diagrams in scientific research articles, several software systems have been developed. But their algorithmic performance and utility in cheminformatic research have not been investigated. Results This paper aims to provide critical reviews for these systems and also report our recent development of ChemReader – a fully automated tool for extracting chemical structure diagrams in research articles and converting them into standard, searchable chemical file formats. Basic algorithms for recognizing lines and letters representing bonds and atoms in chemical structure diagrams can be independently run in sequence from a graphical user interface-and the algorithm parameters can be readily changed-to facilitate additional development specifically tailored to a chemical database annotation scheme. Compared with existing software programs such as OSRA, Kekule, and CLiDE, our results indicate that ChemReader outperforms other software systems on several sets of sample images from diverse sources in terms of the rate of correct outputs and the accuracy on extracting molecular substructure patterns. Conclusion The availability of ChemReader as a cheminformatic tool for extracting chemical structure information from digital raster images allows research and development groups to enrich their chemical structure databases by annotating the entries with published research articles. Based on its stable performance and high accuracy, ChemReader may be sufficiently accurate for annotating the chemical database with links

  13. Secondary Structural Models (16S rRNA of Polyhydroxyalkanoates Producing Bacillus Species Isolated from Different Rhizospheric Soil: Phylogenetics and Chemical Analysis

    Directory of Open Access Journals (Sweden)

    Swati Mohapatra

    2016-09-01

    Full Text Available Polyhydroxyalkanoates (PHAs producing bacterial isolates are gaining more importance over the world due to the synthesis of a biodegradable polymer which is extremely desirable to substitute synthetic plastics. PHAs are produced by various microorganisms under certain stress conditions. In this study, sixteen bacterial isolates characterized previously by partial 16S rRNA gene sequencing (NCBI Accession No. KF626466 to KF626481 were again stained by Nile red after three years of preservation in order to confirm their ability to accumulate PHAs. Also, phylogenetic analysis carried out in the present investigation evidenced that the bacterial species belonging to genus Bacillus are the dominant flora of the rhizospheric region, with a potentiality of biodegradable polymer (PHAs production. Again, RNA secondary structure prediction hypothesized that there is no direct correlation between RNA folding pattern stability with a rate of PHAs production among the selected isolates of genus Bacillus.

  14. Structural dynamics analysis

    Science.gov (United States)

    Housner, J. M.; Anderson, M.; Belvin, W.; Horner, G.

    1985-01-01

    Dynamic analysis of large space antenna systems must treat the deployment as well as vibration and control of the deployed antenna. Candidate computer programs for deployment dynamics, and issues and needs for future program developments are reviewed. Some results for mast and hoop deployment are also presented. Modeling of complex antenna geometry with conventional finite element methods and with repetitive exact elements is considered. Analytical comparisons with experimental results for a 15 meter hoop/column antenna revealed the importance of accurate structural properties including nonlinear joints. Slackening of cables in this antenna is also a consideration. The technology of designing actively damped structures through analytical optimization is discussed and results are presented.

  15. Branch structure of corona discharge: experimental simulation and chemical properties

    International Nuclear Information System (INIS)

    The branch structure of corona discharge has been investigated via C2H2 corona discharge. Carbon filament with excellent branch structure is formed in the discharge. This carbon filament offers a direct mimic of the branch structure of corona discharge. It provides a very useful way to study on the average energy, physical and chemical characteristics of corona discharge. On this basis, the chemical property of corona discharge for methane conversion is discussed. (authors)

  16. The double-layered chemical structure in DB white dwarfs

    OpenAIRE

    Althaus, L.G.; Corsico, A. H.

    2004-01-01

    We study the structure and evolution of white dwarf stars with helium-rich atmospheres (DB) in a self-consistent way with the predictions of time-dependent element diffusion. Our treatment of diffusion includes gravitational settling and chemical and thermal diffusion. OPAL radiative opacities for arbitrary metallicity and carbon-and oxygen-rich compositions are employed. Emphasis is placed on the evolution of the diffusion-modeled double-layered chemical structure. This structure, which is c...

  17. Chemical abundance analysis of 19 barium stars

    CERN Document Server

    Yang, G C; Spite, M; Chen, Y Q; Zhao, G; Zhang, B; Liu, G Q; Liu, Y J; Liu, N; Deng, L C; Spite, F; Hill, V; Zhang, C X

    2016-01-01

    We aim at deriving accurate atmospheric parameters and chemical abundances of 19 barium (Ba) stars, including both strong and mild Ba stars, based on the high signal-to-noise ratio and high resolution Echelle spectra obtained from the 2.16 m telescope at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. The chemical abundances of the sample stars were obtained from an LTE, plane-parallel and line-blanketed atmospheric model by inputting the atmospheric parameters (effective temperatures, surface gravities, metallicity and microturbulent velocity) and equivalent widths of stellar absorption lines. These samples of Ba stars are giants indicated by atmospheric parameters, metallicities and kinematic analysis about UVW velocity. Chemical abundances of 17 elements were obtained for these Ba stars. Their light elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn and Ni) are similar to the solar abundances. Our samples of Ba stars show obvious overabundances of neutron-capture (n-ca...

  18. Surface chemical composition analysis of heat-treated bamboo

    Science.gov (United States)

    Meng, Fan-dan; Yu, Yang-lun; Zhang, Ya-mei; Yu, Wen-ji; Gao, Jian-min

    2016-05-01

    In this study, the effect of heat treatment on the chemical composition of bamboo slivers was studied. The chemical properties of the samples were examined by chemical analysis. Results showed a decrease in the contents of holocellulose and α-cellulose, as well as an increase in the contents of lignin and extractives. Changes in the chemical structure of bamboo components were analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). FTIR spectroscopy results indicated that hemicellulose contents decrease, whereas lignin contents increase after heat treatment. Ester formation linked to lignin decreased the hygroscopicity of the bamboo samples and consequently improved their dimensional stability and durability. XPS spectroscopy results showed that hemicelluloses and celluloses are relatively more sensitive to the heating process than lignin. As a consequence, hemicellulose and cellulose contents decreased, whereas lignin contents increased during heat treatment. The results obtained in this study provide useful information for the future utilization of heat-treated bamboo.

  19. Characterization of iron-phosphate-silicate chemical garden structures.

    Science.gov (United States)

    Barge, Laura M; Doloboff, Ivria J; White, Lauren M; Stucky, Galen D; Russell, Michael J; Kanik, Isik

    2012-02-28

    Chemical gardens form when ferrous chloride hydrate seed crystals are added or concentrated solutions are injected into solutions of sodium silicate and potassium phosphate. Various precipitation morphologies are observed depending on silicate and phosphate concentrations, including hollow plumes, bulbs, and tubes. The growth of precipitates is controlled by the internal osmotic pressure, fluid buoyancy, and membrane strength. Additionally, rapid bubble-led growth is observed when silicate concentrations are high. ESEM/EDX analysis confirms compositional gradients within the membranes, and voltage measurements across the membranes during growth show a final potential of around 150-200 mV, indicating that electrochemical gradients are maintained across the membranes as growth proceeds. The characterization of chemical gardens formed with iron, silicate, and phosphate, three important components of an early earth prebiotic hydrothermal system, can help us understand the properties of analogous structures that likely formed at submarine alkaline hydrothermal vents in the Hadean-structures offering themselves as the hatchery of life. PMID:22035594

  20. Near-field Optical Imagigng and Chemical Analysis

    Science.gov (United States)

    Andres, La Rosa

    1998-03-01

    Identification of molecular structures in complex mixtures represents a major challenge in chemical research today. Microfabricated devices or lab-on-a-chip that perform chemical analysis allows dynamic sampling of picoliter microenvironments and separation. The long-term goals of nanochemistry down to the femtoliter scale involve refinement of the detection limit to single-molecule. Our approach consists in designing a very sensitive near-field optical microscope (NSOM-SIAM) to explore the mesoscopic properties of organic compounds. The validity, sensitivity and unique spatial resolution of this system will be discussed for multiple analyte chemosensing.

  1. The Chemical Validation and Standardization Platform (CVSP): large-scale automated validation of chemical structure datasets

    OpenAIRE

    Karapetyan, Karen; Batchelor, Colin; Sharpe, David; Tkachenko, Valery; Williams, Antony J

    2015-01-01

    Background There are presently hundreds of online databases hosting millions of chemical compounds and associated data. As a result of the number of cheminformatics software tools that can be used to produce the data, subtle differences between the various cheminformatics platforms, as well as the naivety of the software users, there are a myriad of issues that can exist with chemical structure representations online. In order to help facilitate validation and standardization of chemical stru...

  2. Chemical Bond Analysis of Single Crystal Growth of Magnesium Oxide

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Starting from the crystallographic structure of magnesium oxide (MgO), both the chemical bond model of solids and Pauling's third rule (polyhedral sharing rule) were employed to quantitatively analyze the chemical bonding structure of constituent atoms and single crystal growth. Our analytical results show that MgO single crystals prefer to grow along the direction and the growth rate of the {100} plane is the slowest one. Therefore, the results show that the {100} plane of MgO crystals can be the ultimate morphology face, which is in a good agreement with our previous experimental results. The study indicate that the structure analysis is an effective tool to control the single-crystal growth.

  3. Chemical Diversity, Origin, and Analysis of Phycotoxins

    DEFF Research Database (Denmark)

    Rasmussen, Silas Anselm; Andersen, Aaron John Christian; Andersen, Nikolaj Gedsted;

    2016-01-01

    Microalgae, particularly those from the lineage Dinoflagellata, are very well-known for their ability to produce phycotoxins that may accumulate in the marine food chain and eventually cause poisoning in humans. This includes toxins accumulating in shellfish, such as saxitoxin, okadaic acid......, yessotoxins, azaspiracids, brevetoxins, and pinnatoxins. Other toxins, such as ciguatoxins and maitotoxins, accumulate in fish, where, as is the case for the latter compounds, they can be metabolized to even more toxic metabolites. On the other hand, much less is known about the chemical nature of compounds...... complex natural compounds known to mankind, with chemical structures that show no resemblance to what has been characterized from plants, fungi, or bacteria. In addition, it will summarize algal species known to be related to fish-killing blooms, but from which ichthyotoxins are yet to be characterized....

  4. Chemical durability and structural analysis of PbO–B{sub 2}O{sub 3} glasses and testing for simulated radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    Erdogan, Cem [Ege University Institute of Nuclear Sciences, 35100 Bornova, Izmir (Turkey); Bengisu, Murat [Izmir University of Economics, Department of Industrial Design, Sakarya Cad., No. 156, 35330 Balcova, Izmir (Turkey); Erenturk, Sema Akyil, E-mail: erenturk@itu.edu.tr [Istanbul Technical University, Energy Institute, 34469 Maslak, Istanbul (Turkey)

    2014-02-01

    Graphical abstract: Secondary electron SEM images of lead borate glass including 80 mol% PbO before (top) and after chemical durability tests (bottom) - Abstract: Lead borate based glass formulations with high chemical durability and lower melting temperatures compared to the currently used glasses were developed as candidates for the vitrification of radioactive waste. Properties including chemical durability, glass transformation temperature, and melting temperature were analyzed. The chemical durability of PbO–B{sub 2}O{sub 3} glasses with PbO contents ranging from 30 to 80 mol% was determined. An average dissolution rate of 0.2 g m{sup −2} day{sup −1} was obtained for the composition 80PbO⋅20B{sub 2}O{sub 3}. These glasses were studied under simulation conditions and showed good potential as a vitrification matrix for radioactive waste management. Clear vitrified waste products containing up to 30 mol% SrO and 25 mol% Cs{sub 2}O could be obtained. Leaching rates are about hundred times higher in low PbO glasses compared to high PbO glasses. These results are encouraging since they open up new horizons in the development of low melting temperature lead borate glass for waste immobilization applications.

  5. Corporate Shareholding Structure and Dividend Payout Ratio of Listed Chemical and Paints Companies in Nigeria

    OpenAIRE

    Kabiru Isa Dandago; Musa Adeiza Farouk; Latifat Muhibudeen

    2015-01-01

    This paper is an empirical analysis of influence of Corporate Shareholdings Structure on Dividend payout ratio of listed Chemical and Paints Companies in Nigeria. The study is for the period of 2008-2013. The listed Chemical and Paints Companies are Eight (8) in number as provided by Nigerian stock exchange factbook for 2013. All the eight firms were used for the study. Corporate Shareholdings Structure was proxy with managerial shareholding, institutional shareholding, block shareholding and...

  6. Chemical detection, identification, and analysis system

    International Nuclear Information System (INIS)

    The chemical detection, identification, and analysis system (CDIAS) has three major goals. The first is to display safety information regarding chemical environment before personnel entry. The second is to archive personnel exposure to the environment. Third, the system assists users in identifying the stage of a chemical process in progress and suggests safety precautions associated with that process. In addition to these major goals, the system must be sufficiently compact to provide transportability, and it must be extremely simple to use in order to keep user interaction at a minimum. The system created to meet these goals includes several pieces of hardware and the integration of four software packages. The hardware consists of a low-oxygen, carbon monoxide, explosives, and hydrogen sulfide detector; an ion mobility spectrometer for airborne vapor detection; and a COMPAQ 386/20 portable computer. The software modules are a graphics kernel, an expert system shell, a data-base management system, and an interface management system. A supervisory module developed using the interface management system coordinates the interaction of the other software components. The system determines the safety of the environment using conventional data acquisition and analysis techniques. The low-oxygen, carbon monoxide, hydrogen sulfide, explosives, and vapor detectors are monitored for hazardous levels, and warnings are issued accordingly

  7. Analysis of Chemical Technology Division waste streams

    International Nuclear Information System (INIS)

    This document is a summary of the sources, quantities, and characteristics of the wastes generated by the Chemical Technology Division (CTD) of the Oak Ridge National Laboratory. The major contributors of hazardous, mixed, and radioactive wastes in the CTD as of the writing of this document were the Chemical Development Section, the Isotopes Section, and the Process Development Section. The objectives of this report are to identify the sources and the summarize the quantities and characteristics of hazardous, mixed, gaseous, and solid and liquid radioactive wastes that are generated by the Chemical Technology Division (CTD) of the Oak Ridge National Laboratory (ORNL). This study was performed in support of the CTD waste-reduction program -- the goals of which are to reduce both the volume and hazard level of the waste generated by the division. Prior to the initiation of any specific waste-reduction projects, an understanding of the overall waste-generation system of CTD must be developed. Therefore, the general approach taken in this study is that of an overall CTD waste-systems analysis, which is a detailed presentation of the generation points and general characteristics of each waste stream in CTD. The goal of this analysis is to identify the primary waste generators in the division and determine the most beneficial areas to initiate waste-reduction projects. 4 refs., 4 figs., 13 tabs

  8. Chemical isomeric effects on propanol glassy structures

    CERN Document Server

    Cuello, G J; Bermejo, F J; Cabrillo, C

    2002-01-01

    We have studied the structure of both propanol isomers in their glassy and crystalline states by neutron diffraction. The glass-transition temperatures of 1- and 2-propanol are about 98 and 115 K, respectively and, surprisingly, even larger differences are observed for the melting temperatures of the stable crystals, which are 148 and 185 K, respectively. Their supercooled liquid phases show rather different relaxation spectra, 1-propanol manifesting strong deviations from Debye behavior, whereas 2-propanol shows a far weaker effect. We discuss the spectra obtained for the static structure factor and the static pair correlation function D(r). There is a noticeable difference in the position of the first sharp diffraction peak, which clearly indicates a density change, well correlated with the period of the intermolecular oscillations shown by D(r). (orig.)

  9. Bayesian inference of protein structure from chemical shift data

    DEFF Research Database (Denmark)

    Bratholm, Lars Andersen; Christensen, Anders Steen; Hamelryck, Thomas Wim;

    2015-01-01

    Protein chemical shifts are routinely used to augment molecular mechanics force fields in protein structure simulations, with weights of the chemical shift restraints determined empirically. These weights, however, might not be an optimal descriptor of a given protein structure and predictive model......, and a bias is introduced which might result in incorrect structures. In the inferential structure determination framework, both the unknown structure and the disagreement between experimental and back-calculated data are formulated as a joint probability distribution, thus utilizing the full information...... content of the data. Here, we present the formulation of such a probability distribution where the error in chemical shift prediction is described by either a Gaussian or Cauchy distribution. The methodology is demonstrated and compared to a set of empirically weighted potentials through Markov chain...

  10. Structure of chemical vapor deposition titania/silica gel

    Energy Technology Data Exchange (ETDEWEB)

    Leboda, R.; Gun' ko, V.M.; Marciniak, M.; Malygin, A.A.; Malkin, A.A.; Grzegorczyk, W.; Trznadel, B.J.; Pakhlov, E.M.; Voronin, E.F.

    1999-10-01

    The structure of porous silica gel/titania synthesized using chemical vapor deposition (CVD) of titania via repeated reactions of TiCl{sub 4} with the surface and subsequent hydrolysis of residual Ti-Cl bonds at different temperatures was investigated by means of low-temperature nitrogen adsorption-desorption, X-ray diffraction (XRD), IR spectroscopy, and theoretical methods. A globular model of porous solids with corpuscular structure was applied to estimate the porosity parameters of titania/silica gel adsorbents. The utilization of this model is useful, for example, to predict conditions for synthesis of titania/silica with a specified structure. Analysis of pore parameters and fractal dimension suggests that the porosity and fractality of samples decrease with increasing amount of TiO{sub 2} covering the silica gel surface in a nonuniform layer, which represents small particles embedded in pores and larger particles formed at the outer surface of silica globules. Theoretical simulation shows that the Si-O-Ti linkages between the cover and the substrate can be easily hydrolyzed, which is in agreement with the IR data corresponding to the absence of a band at 950 cm {sup {minus}1} (characteristic of Si-O-Ti bridges) independent of the concentration of CVD-titania.

  11. VALIDATION GUIDELINES FOR LABORATORIES PERFORMING FORENSIC ANALYSIS OF CHEMICAL TERRORISM

    Science.gov (United States)

    The Scientific Working Group on Forensic Analysis of Chemical Terrorism (SWGFACT) has developed the following guidelines for laboratories engaged in the forensic analysis of chemical evidence associated with terrorism. This document provides a baseline framework and guidance for...

  12. Inferential protein structure determination and refinement using fast, electronic structure based backbone amide chemical shift predictions

    CERN Document Server

    Christensen, Anders S

    2015-01-01

    This report covers the development of a new, fast method for calculating the backbone amide proton chemical shifts in proteins. Through quantum chemical calculations, structure-based forudsiglese the chemical shift for amidprotonen in protein has been parameterized. The parameters are then implemented in a computer program called Padawan. The program has since been implemented in protein folding program Phaistos, wherein the method andvendes to de novo folding of the protein structures and to refine the existing protein structures.

  13. Structural and Chemical Diversity of Tl-Based Cuprate Superconductors

    Institute of Scientific and Technical Information of China (English)

    信赢

    2003-01-01

    The Tl-based cuprate superconductor family is the largest family in crystal structure and chemical composition among all high Tc cuprate superconductors. The Tl family can be divided into two sub-families, the Tl single layer family and the Tl double layer family, based on their crystal structural characteristics. The Tl single layer family is an ideal material for investigating the evolution of crystalline formation, charge carrier density, chemical composition, transport properties, superconductivity and their relationships. The Tl family contains almostall possible crystal structures discovered in high-Tc cuprate superconductors. Tl cuprate superconductors are of great importance not only in studying high-temperature superconductivity but also in commercial applications.

  14. Chemical composition in relation with biomass ash structure

    Science.gov (United States)

    Holubcik, Michal; Jandacka, Jozef

    2014-08-01

    Biomass combustion can be more complicated like combustion of fossil fuels because it is necessary to solve problems with lower ash melting temperature. It can cause a lot of problems during combustion process. Chemical composition of biomass ash has great impact on sinters and slags creation in ash because it affects structure of heated ash. In this paper was solved relation between chemical composition and structure of heated ash from three types of biomass (spruce wood, miscanthus giganteus and wheat straw). Amount of SiO2, CaO, MgO, Al2O3 and K2O was determined. Structure of heated ash was optically determined after heating to 1000 °C or 1200 °C. Results demonstrated that chemical composition has strong effect on structure and color of heated ash.

  15. Designing Allosteric Control into Enzymes by Chemical Rescue of Structure

    Energy Technology Data Exchange (ETDEWEB)

    Deckert, Katelyn; Budiardjo, S. Jimmy; Brunner, Luke C.; Lovell, Scott; Karanicolas, John (Kansas)

    2012-08-07

    Ligand-dependent activity has been engineered into enzymes for purposes ranging from controlling cell morphology to reprogramming cellular signaling pathways. Where these successes have typically fused a naturally allosteric domain to the enzyme of interest, here we instead demonstrate an approach for designing a de novo allosteric effector site directly into the catalytic domain of an enzyme. This approach is distinct from traditional chemical rescue of enzymes in that it relies on disruption and restoration of structure, rather than active site chemistry, as a means to achieve modulate function. We present two examples, W33G in a {beta}-glycosidase enzyme ({beta}-gly) and W492G in a {beta}-glucuronidase enzyme ({beta}-gluc), in which we engineer indole-dependent activity into enzymes by removing a buried tryptophan side chain that serves as a buttress for the active site architecture. In both cases, we observe a loss of function, and in both cases we find that the subsequent addition of indole can be used to restore activity. Through a detailed analysis of {beta}-gly W33G kinetics, we demonstrate that this rescued enzyme is fully functionally equivalent to the corresponding wild-type enzyme. We then present the apo and indole-bound crystal structures of {beta}-gly W33G, which together establish the structural basis for enzyme inactivation and rescue. Finally, we use this designed switch to modulate {beta}-glycosidase activity in living cells using indole. Disruption and recovery of protein structure may represent a general technique for introducing allosteric control into enzymes, and thus may serve as a starting point for building a variety of bioswitches and sensors.

  16. Systems analysis of past, present, and future chemical terrorism scenarios.

    Energy Technology Data Exchange (ETDEWEB)

    Hoette, Trisha Marie

    2012-03-01

    Throughout history, as new chemical threats arose, strategies for the defense against chemical attacks have also evolved. As a part of an Early Career Laboratory Directed Research and Development project, a systems analysis of past, present, and future chemical terrorism scenarios was performed to understand how the chemical threats and attack strategies change over time. For the analysis, the difficulty in executing chemical attack was evaluated within a framework of three major scenario elements. First, historical examples of chemical terrorism were examined to determine how the use of chemical threats, versus other weapons, contributed to the successful execution of the attack. Using the same framework, the future of chemical terrorism was assessed with respect to the impact of globalization and new technologies. Finally, the efficacy of the current defenses against contemporary chemical terrorism was considered briefly. The results of this analysis justify the need for continued diligence in chemical defense.

  17. Structural and chemical analysis of silica-doped β-TCP ceramic coatings on surgical grade 316L SS for possible biomedical application

    Directory of Open Access Journals (Sweden)

    Karuppasamy Prem Ananth

    2015-09-01

    Full Text Available We have developed a novel approach to introduce silica-doped β-tricalcium phosphate (Si-β-TCP on 316L SS substrates for enhanced biological properties. Doping of β-TCP with silica loadings ranging from 0 to 8 mol% was carried out using chemical precipitation method. Si-β-TCP powder was sintered at 800 °C followed by coating it on 316L SS substrate using electrophoretic deposition. The coated and uncoated samples were investigated by various characterization techniques such as X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, field emission scanning electron microscopy (FESEM and X-ray fluorescence spectroscopy (XRF. Biomineralization ability of the coatings was evaluated by immersing in simulated body fluid (SBF solution for different number of days such as 7, 14, 21 and 28 days. The results obtained in our study have shown that the apatite formation ability was high for the 8 mol% of Si-β-TCP. This will promote better biomineralization ability compared to the other coatings.

  18. Improving 3D structure prediction from chemical shift data

    Energy Technology Data Exchange (ETDEWEB)

    Schot, Gijs van der [Utrecht University, Computational Structural Biology, Bijvoet Center for Biomolecular Research, Faculty of Science-Chemistry (Netherlands); Zhang, Zaiyong [Technische Universitaet Muenchen, Biomolecular NMR and Munich Center for Integrated Protein Science, Department Chemie (Germany); Vernon, Robert [University of Washington, Department of Biochemistry (United States); Shen, Yang [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States); Vranken, Wim F. [VIB, Department of Structural Biology (Belgium); Baker, David [University of Washington, Department of Biochemistry (United States); Bonvin, Alexandre M. J. J., E-mail: a.m.j.j.bonvin@uu.nl [Utrecht University, Computational Structural Biology, Bijvoet Center for Biomolecular Research, Faculty of Science-Chemistry (Netherlands); Lange, Oliver F., E-mail: oliver.lange@tum.de [Technische Universitaet Muenchen, Biomolecular NMR and Munich Center for Integrated Protein Science, Department Chemie (Germany)

    2013-09-15

    We report advances in the calculation of protein structures from chemical shift nuclear magnetic resonance data alone. Our previously developed method, CS-Rosetta, assembles structures from a library of short protein fragments picked from a large library of protein structures using chemical shifts and sequence information. Here we demonstrate that combination of a new and improved fragment picker and the iterative sampling algorithm RASREC yield significant improvements in convergence and accuracy. Moreover, we introduce improved criteria for assessing the accuracy of the models produced by the method. The method was tested on 39 proteins in the 50-100 residue size range and yields reliable structures in 70 % of the cases. All structures that passed the reliability filter were accurate (<2 A RMSD from the reference)

  19. Structural analysis of DNA by autoradiography

    International Nuclear Information System (INIS)

    During the past 10 years, molecular biology has rapidly been developing owing to easy structural analysis of DNA, a fundamental substance involved in life function. The application of highly sensitive RI with the production of large amounts of DNA and with no change in the chemical property of the substance to be tested has greatly contributed to molecular biology. For the development of life science and biotechnology, it is essential to analyze basic arrangement of DNA, identify genes, predict amino acid arrangement of proteins, and clarify regulation mechanism involved in genes. To understand DNA function sufficiently, analysis of secondary or tertiary structure, as well as primary structure of DNA, is extremely important. In this paper, the primary DNA structural analysis is provided in relation to RI application. Structural analysis of DNA can be classified into (1) hybridization method and (2) basic arrangement determination method. The application of DNA analysis is discussed in terms of the following: (1) varified analysis of the antibody, (2) isolation and analysis of carcinogenic genes, and (3) gene diagnosis. There is a problem with manual process in the structural analysis of DNA. Currently, automatic apparatuses for extraction, purification, reaction, isolation, and detection of DNA have been developing. (N.K.)

  20. Design of LTCC-based Ceramic Structure for Chemical Microreactor

    OpenAIRE

    D. Belavic; Hrovat, M.; G. Dolanc; Santo Zarnik, M.; Holc, J.; Makarovic, K.

    2012-01-01

    The design of ceramic chemical microreactor for the production of hydrogen needed in portable polymer-electrolyte membrane (PEM) fuel cells is presented. The microreactor was developed for the steam reforming of liquid fuels with water into hydrogen. The complex three-dimensional ceramic structure of the microreactor includes evaporator(s), mixer(s), reformer and combustor. Low-temperature co-fired ceramic (LTCC) technology was used to fabricate the ceramic structures with buried cavities and...

  1. Char Chemical Structure Analysis of Intumescent Flame Retardant Polypropylene after Burning%膨胀阻燃聚丙烯燃烧残炭的结构分析

    Institute of Scientific and Technical Information of China (English)

    梁敏仪; 黄秋芬; 刘祥军; 冯才敏

    2014-01-01

    采用离子色谱法测定残炭提取液中离子及其含量,并用红外光谱仪和X-荧光光谱法(EDX)分析了残炭在浸泡前后的结构变化。结果表明,在超纯水中浸泡得到磷酸根离子;在80℃温度下,震荡提取72小时后,提取液中磷酸根离子浓度达到最大值;提取后残炭中磷含量显下降,P-O-P和P-O-C结构的吸收峰显著减小。说明,残炭中大部分的P-O-P和P-O-C键水解成磷酸根,残留的P可能进入残炭的环状结构或与环状结构直接相连。%The kind and content of anion in the char was determinated by ion chromatography, and the structure was characterized by Fourier Transform infrared spectroscopy (FTIR) and X-ray Fluorescence Spectrometer (EDX). The re-sults showed that phosphate group was detected in the solution;when the temperature was 80 oC and the soak time was 72 hours, the value of phosphate group in the solution reach the maximum;the P content decreased with the decrease of P-O-P and P-O-C absorption strength, which revealed that P-O-P and P-O-C bond were hydrolysed to phosphate group, and the residual P entered polyaromatic ring or connected to polyaromatic ring directlt.

  2. The multifractal structure of chaotically advected chemical fields

    CERN Document Server

    Neufeld, Z; Hernández-García, E; Tél, T; Neufeld, Zoltan; Lopez, Cristobal; Hernandez-Garcia, Emilio; Tel, Tamas

    1999-01-01

    The structure of the concentration field of a decaying substance produced by chemical sources and advected by a smooth incompressible two-dimensional flow is investigated. We focus our attention on the non-uniformities of the Hölder exponent of the resulting filamental chemical field. They appear most evidently in the case of open flows where irregularities of the field exhibit strong spatial intermittency as they are restricted to a fractal manifold. Non-uniformities of the Hölder exponent of the chemical field in closed flows appears as a consequence of the non-uniform stretching of the fluid elements. We study how this affects the scaling exponents of the structure functions, displaying anomalous scaling, and relate the scaling exponents to the distribution of finite-time Lyapunov exponents of the advection dynamics. Theoretical predictions are compared with numerical experiments.

  3. Structural studies of chemical constituents of Thithonia Tagetiflora Desv (Asteraceae)

    DEFF Research Database (Denmark)

    Ngoc Huynh, Vinh; Nguyen Thi Hoai, Thu; Phi Phung Nguyen, Kim;

    2013-01-01

    Tithonia tagetiflora Desv. (Asteraceae) is a widespread plant in Vietnam, and the species of Tithonia are known as plants containing many biologically active compounds. However, T. tagetiflora's chemical composition remains mostly unknown. Therefore, we now report the structural elucidation of two...

  4. Electronic and chemical properties of graphene-based structures:

    DEFF Research Database (Denmark)

    Vanin, Marco

    are easier to remove and therefore only zigzag edges are left. Finally, functionalized graphene has been investigated as catalyst for the electrochemical reduction of CO2 to chemical fuels and comparisons are made with traditional transition-metal surfaces. The investigated porphyrin-like structures...... are attractive candidates although issues regarding the poisoning of the active site remain to be addressed....

  5. Integrated polymer waveguides for absorbance detection in chemical analysis systems

    DEFF Research Database (Denmark)

    Mogensen, Klaus Bo; El-Ali, Jamil; Wolff, Anders;

    2003-01-01

    A chemical analysis system for absorbance detection with integrated polymer waveguides is reported for the first time. The fabrication procedure relies on structuring of a single layer of the photoresist SU-8, so both the microfluidic channel network and the optical components, which include plan...... of the dye Bromothymol Blue. The influence of three different bonding procedures on the spectrally resolved propagation loss of the integrated waveguides between 500 nm and 900 nm was furthermore determined.......A chemical analysis system for absorbance detection with integrated polymer waveguides is reported for the first time. The fabrication procedure relies on structuring of a single layer of the photoresist SU-8, so both the microfluidic channel network and the optical components, which include planar...... waveguides and fiber-to-waveguide coupler structures, are defined in the same processing step. This results in self-alignment of all components and enables a fabrication and packaging time of only one day. The fabrication scheme has recently been presented elsewhere for fluorescence excitation of beads...

  6. Nepheline structural and chemical dependence on melt composition

    Energy Technology Data Exchange (ETDEWEB)

    Marcial, José; Crum, Jarrod; Neill, Owen; McCloy, John

    2016-02-01

    Nepheline crystallizes upon slow-cooling in some melts concentrated in Na2O and Al2O3, which can result in a residual glass phase of low chemical durability. Nepheline can incorporate many components often found in high-level waste radioactive borosilicate glass, including glass network ions (e.g., Si, Al, Fe), alkali metals (e.g., Cs, K, Na, and possibly Li), alkaline-earth metals (e.g., Ba, Sr, Ca, Mg), and transition metals (e.g., Mn, and possibly Cr, Zn, Ni). When crystallized from melts of different compositions, nepheline chemistry varies as a function of starting glass composition. Five simulated high level nuclear waste borosilicate glasses shown to crystallize large fractions of nepheline on slow cooling, were selected for study. These melts constituted a range of Al2O3, B2O3, CaO, Na2O, K2O, Fe2O3, and SiO2 compositions. Compositional analyses of nepheline crystals in glass by electron probe micro-analysis (EPMA) indicate that boron is unlikely to be present in any significant concentration, if at all, in nepheline. Also, several models are presented for calculating the fraction of vacancies in the nepheline structure.

  7. Discovering More Chemical Concepts from 3D Chemical Information Searches of Crystal Structure Databases

    Science.gov (United States)

    Rzepa, Henry S.

    2016-01-01

    Three new examples are presented illustrating three-dimensional chemical information searches of the Cambridge structure database (CSD) from which basic core concepts in organic and inorganic chemistry emerge. These include connecting the regiochemistry of aromatic electrophilic substitution with the geometrical properties of hydrogen bonding…

  8. Chemical abundance analysis of 19 barium stars

    Science.gov (United States)

    Yang, Guo-Chao; Liang, Yan-Chun; Spite, Monique; Chen, Yu-Qin; Zhao, Gang; Zhang, Bo; Liu, Guo-Qing; Liu, Yu-Juan; Liu, Nian; Deng, Li-Cai; Spite, Francois; Hill, Vanessa; Zhang, Cai-Xia

    2016-01-01

    We aim at deriving accurate atmospheric parameters and chemical abundances of 19 barium (Ba) stars, including both strong and mild Ba stars, based on the high signal-to-noise ratio and high resolution Echelle spectra obtained from the 2.16 m telescope at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. The chemical abundances of the sample stars were obtained from an LTE, plane-parallel and line-blanketed atmospheric model by inputting the atmospheric parameters (effective temperatures Teff, surface gravities log g, metallicity [Fe/H] and microturbulence velocity ξt) and equivalent widths of stellar absorption lines. These samples of Ba stars are giants as indicated by atmospheric parameters, metallicities and kinematic analysis about UVW velocity. Chemical abundances of 17 elements were obtained for these Ba stars. Their Na, Al, α- and iron-peak elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Ni) are similar to the solar abundances. Our samples of Ba stars show obvious overabundances of neutron-capture (n-capture) process elements relative to the Sun. Their median abundances of [Ba/Fe], [La/Fe] and [Eu/Fe] are 0.54, 0.65 and 0.40, respectively. The Y I and Zr I abundances are lower than Ba, La and Eu, but higher than the α- and iron-peak elements for the strong Ba stars and similar to the iron-peak elements for the mild stars. There exists a positive correlation between Ba intensity and [Ba/Fe]. For the n-capture elements (Y, Zr, Ba, La), there is an anti-correlation between their [X/Fe] and [Fe/H]. We identify nine of our sample stars as strong Ba stars with [Ba/Fe] >0.6 where seven of them have Ba intensity Ba=2-5, one has Ba=1.5 and another one has Ba=1.0. The remaining ten stars are classified as mild Ba stars with 0.17<[Ba/Fe] <0.54.

  9. Effect of mechanical activation on structure changes and reactivity in further chemical modification of lignin.

    Science.gov (United States)

    Zhao, Xiaohong; Zhang, Yanjuan; Hu, Huayu; Huang, Zuqiang; Yang, Mei; Chen, Dong; Huang, Kai; Huang, Aimin; Qin, Xingzhen; Feng, Zhenfei

    2016-10-01

    Lignin was treated by mechanical activation (MA) in a customized stirring ball mill, and the structure and reactivity in further esterification were studied. The chemical structure and morphology of MA-treated lignin and the esterified products were analyzed by chemical analysis combined with UV/vis spectrometer, FTIR,NMR, SEM and particle size analyzer. The results showed that MA contributed to the increase of aliphatic hydroxyl, phenolic hydroxyl, carbonyl and carboxyl groups but the decrease of methoxyl groups. Moreover, MA led to the decrease of particle size and the increase of specific surface area and roughness of surface in lignin. The reactivity of lignin was enhanced significantly for the increase of hydroxyl content and the improvement of mass transfer in chemical reaction caused by the changes of molecular structure and morphological structure. The process of MA is green and simple, and is an effective method for enhancing the reactivity of lignin. PMID:27344951

  10. Spectroscopic Chemical Analysis Methods and Apparatus

    Science.gov (United States)

    Hug, William F.; Reid, Ray D.

    2012-01-01

    This invention relates to non-contact spectroscopic methods and apparatus for performing chemical analysis and the ideal wavelengths and sources needed for this analysis. It employs deep ultraviolet (200- to 300-nm spectral range) electron-beam-pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor lightemitting devices, and hollow cathode metal ion lasers. Three achieved goals for this innovation are to reduce the size (under 20 L), reduce the weight [under 100 lb (.45 kg)], and reduce the power consumption (under 100 W). This method can be used in microscope or macroscope to provide measurement of Raman and/or native fluorescence emission spectra either by point-by-point measurement, or by global imaging of emissions within specific ultraviolet spectral bands. In other embodiments, the method can be used in analytical instruments such as capillary electrophoresis, capillary electro-chromatography, high-performance liquid chromatography, flow cytometry, and related instruments for detection and identification of unknown analytes using a combination of native fluorescence and/or Raman spectroscopic methods. This design provides an electron-beampumped semiconductor radiation-producing method, or source, that can emit at a wavelength (or wavelengths) below 300 nm, e.g. in the deep ultraviolet between about 200 and 300 nm, and more preferably less than 260 nm. In some variations, the method is to produce incoherent radiation, while in other implementations it produces laser radiation. In some variations, this object is achieved by using an AlGaN emission medium, while in other implementations a diamond emission medium may be used. This instrument irradiates a sample with deep UV radiation, and then uses an improved filter for separating wavelengths to be detected. This provides a multi-stage analysis of the sample. To avoid the difficulties related to producing deep UV semiconductor sources, a pumping approach has been developed that uses

  11. Global Materials Structure Search with Chemically Motivated Coordinates.

    Science.gov (United States)

    Panosetti, Chiara; Krautgasser, Konstantin; Palagin, Dennis; Reuter, Karsten; Maurer, Reinhard J

    2015-12-01

    Identification of relevant reaction pathways in ever more complex composite materials and nanostructures poses a central challenge to computational materials discovery. Efficient global structure search, tailored to identify chemically relevant intermediates, could provide the necessary first-principles atomistic insight to enable a rational process design. In this work we modify a common feature of global geometry optimization schemes by employing automatically generated collective curvilinear coordinates. The similarity of these coordinates to molecular vibrations enhances the generation of chemically meaningful trial structures for covalently bound systems. In the application to hydrogenated Si clusters, we concomitantly observe a significantly increased efficiency in identifying low-energy structures and exploit it for an extensive sampling of potential products of silicon-cluster soft landing on Si(001) surfaces.

  12. [Chemical structure and immunomodulating activities of peptidoglycan from Actinobacillus actinomycetemcomitans].

    Science.gov (United States)

    Kinoshita, F

    1989-12-01

    The chemical structure and immunomodulating activities of the cell wall peptidoglycans isolated from Actinobacillus actinomycetemcomitans were investigated. Peptidoglycans were isolated from A. actinomycetemcomitans strains Y4 and ATCC 29522 by boiling in 4% sodium dodecyl sulfate and by digestion with pronase, trypsin and alpha-amylase. Analysis of amino acids and amino sugars of the peptidoglycans revealed that glucosamine, muramic acid, D-glutamic acid, D-alanine, and meso-2, 6-diaminopimelic acid (A2pm) were the principal components. Serine and glycine were not found. Dinitrophenylation method revealed that about half of A2pm residue had a free aminogroup, and analysis by hydrazinolysis showed that a small part of alanine and A2pm located at the C-terminal. The above results indicate that one of the amino groups of A2pm residue at one strand of the stem peptide subunit crosslinked to the carboxyl group of alanine of the neighboring strand. It was thus revealed that the peptidoglycans of A. actinomycetemcomitans belonged to the Al gamma type of the classification by Schleifer and Kandler. Peptidoglycans isolated from A. actinomycetemcmitans strain Y4 and ATCC 29522 were found to be definitely adjuvant-active in induction of delayed type hypersensitivity against ovalbumin when administered to guinea pigs as water-in oil emulsion and stimulation of increase serum antibody levels was found in both peptidoglycans. Regarding mitogenicity on splenocytes of BALB/c and BALB/c nu/nu mice, peptidoglycans from two strains of A. actinomycetemcomitans were markedly enhanced the uptake [3H] thymidine in dose of 10 micrograms/10(5) cells, however thymocytes were not reactive. Stimulation effects on peritoneal macrophages from a guinea pig to incorporation of 14C-glucosamin were not exhibited on addition of 100 micrograms of both peptidoglycans. These findings indicate that peptidoglycan of A. actinomycetemcomitans might eventually be responsible for destruction of periodontal

  13. Structure activity relationships to assess new chemicals under TSCA

    Energy Technology Data Exchange (ETDEWEB)

    Auletta, A.E. [Environmental Protection Agency, Washington, DC (United States)

    1990-12-31

    Under Section 5 of the Toxic Substances Control Act (TSCA), manufacturers must notify the US Environmental Protection Agency (EPA) 90 days before manufacturing, processing, or importing a new chemical substance. This is referred to as a premanufacture notice (PMN). The PMN must contain certain information including chemical identity, production volume, proposed uses, estimates of exposure and release, and any health or environmental test data that are available to the submitter. Because there is no explicit statutory authority that requires testing of new chemicals prior to their entry into the market, most PMNs are submitted with little or no data. As a result, EPA has developed special techniques for hazard assessment of PMN chemicals. These include (1) evaluation of available data on the chemical itself, (2) evaluation of data on analogues of the PMN, or evaluation of data on metabolites or analogues of metabolites of the PMN, (3) use of quantitative structure activity relationships (QSARs), and (4) knowledge and judgement of scientific assessors in the interpretation and integration of the information developed in the course of the assessment. This approach to evaluating potential hazards of new chemicals is used to identify those that are most in need of addition review of further testing. It should not be viewed as a replacement for testing. 4 tabs.

  14. Structure of adsorbed monolayers. The surface chemical bond

    International Nuclear Information System (INIS)

    This paper attempts to provide a summary of what has been learned about the structure of adsorbed monolayers and about the surface chemical bond from molecular surface science. While the surface chemical bond is less well understood than bonding of molecules in the gas phase or in the solid state, our knowledge of its properties is rapidly accumulating. The information obtained also has great impact on many surface science based technologies, including heterogeneous catalysis and electronic devices. It is hoped that much of the information obtained from studies at solid-gas interfaces can be correlated with molecular behavior at solid-liquid interfaces. 31 references, 42 figures, 1 table

  15. Structures and their analysis

    CERN Document Server

    Fuchs, Maurice Bernard

    2016-01-01

    Addressing structures, this book presents a classic discipline in a modern setting by combining illustrated examples with insights into the solutions. It is the fruit of the author’s many years of teaching the subject and of just as many years of research into the design of optimal structures. Although intended for an advanced level of instruction it has an undergraduate course at its core. Further, the book was written with the advantage of having massive computer power in the background, an aspect which changes the entire approach to many engineering disciplines and in particular to structures. This paradigm shift has dislodged the force (flexibility) method from its former prominence and paved the way for the displacement (stiffness) method, despite the multitude of linear equations it spawns. In this book, however, both methods are taught: the force method offers a perfect vehicle for understanding structural behavior, bearing in mind that it is the displacement method which does the heavy number crunch...

  16. Crystal and electronic structure analysis and thermodynamic stabilities for electrochemically or chemically delithiated Li1.2-xMn0.54Ni0.13Co0.13O2

    Science.gov (United States)

    Ishida, Naoya; Tamura, Norihide; Kitamura, Naoto; Idemoto, Yasushi

    2016-07-01

    The Li1.2-xMn0.54Ni0.13Co0.13O2 were synthesized by chemical or electrochemical delithiation. The characterization by using the XRD, ICP, synchrotron XRD and thermodynamic measurements were performed for pristine and delithiated compounds. The measured lithium compositions for chemically delithiated Li1.2-xMn0.54Ni0.13Co0.13O2 showed the values of x = 0.31, 0.43, and 0.88, and were nearly the same as the electrochemically delithiated cathodes at 4.3 V, 4.5 V, and 4.8 V, respectively. The crystal and electronic structures for pristine and delithiated samples were analyzed by the Rietveld method using synchrotron X-ray diffraction. As a result, many structural parameters resembled between chemically and electrochemically delithiations up to x ≈ 0.5. Above x ≈ 0.5, the distortion parameters, λ and σ2, and the electronic structures for electrochemically delithiated materials were not coincide with those for corresponding chemically delithiated one. Thermodynamic stabilities of the materials about x ≈ 0.9 were enhanced for electrochemically delithiation. The chemically delithiation of the Li1.2Mn0.54Ni0.13Co0.13O2 enabled the reproduction of the charged active materials up to 4.5 V by using the NO2BF4 oxidizer.

  17. Applications of the Cambridge Structural Database in chemical education.

    Science.gov (United States)

    Battle, Gary M; Ferrence, Gregory M; Allen, Frank H

    2010-10-01

    The Cambridge Structural Database (CSD) is a vast and ever growing compendium of accurate three-dimensional structures that has massive chemical diversity across organic and metal-organic compounds. For these reasons, the CSD is finding significant uses in chemical education, and these applications are reviewed. As part of the teaching initiative of the Cambridge Crystallographic Data Centre (CCDC), a teaching subset of more than 500 CSD structures has been created that illustrate key chemical concepts, and a number of teaching modules have been devised that make use of this subset in a teaching environment. All of this material is freely available from the CCDC website, and the subset can be freely viewed and interrogated using WebCSD, an internet application for searching and displaying CSD information content. In some cases, however, the complete CSD System is required for specific educational applications, and some examples of these more extensive teaching modules are also discussed. The educational value of visualizing real three-dimensional structures, and of handling real experimental results, is stressed throughout.

  18. Applications of the Cambridge Structural Database in chemical education.

    Science.gov (United States)

    Battle, Gary M; Ferrence, Gregory M; Allen, Frank H

    2010-10-01

    The Cambridge Structural Database (CSD) is a vast and ever growing compendium of accurate three-dimensional structures that has massive chemical diversity across organic and metal-organic compounds. For these reasons, the CSD is finding significant uses in chemical education, and these applications are reviewed. As part of the teaching initiative of the Cambridge Crystallographic Data Centre (CCDC), a teaching subset of more than 500 CSD structures has been created that illustrate key chemical concepts, and a number of teaching modules have been devised that make use of this subset in a teaching environment. All of this material is freely available from the CCDC website, and the subset can be freely viewed and interrogated using WebCSD, an internet application for searching and displaying CSD information content. In some cases, however, the complete CSD System is required for specific educational applications, and some examples of these more extensive teaching modules are also discussed. The educational value of visualizing real three-dimensional structures, and of handling real experimental results, is stressed throughout. PMID:20877495

  19. Electronic and chemical structure of metal-silicon interfaces

    Science.gov (United States)

    Grunthaner, P. J.; Grunthaner, F. J.

    1984-01-01

    This paper reviews our current understanding of the near-noble metal silicides and the interfaces formed with Si(100). Using X-ray photoemission spectroscopy, we compare the chemical composition and electronic structure of the room temperature metal-silicon and reacted silicide-silicon interfaces. The relationship between the interfacial chemistry and the Schottky barrier heights for this class of metals on silicon is explored.

  20. Chemical and structural features influencing the biological activity of curcumin.

    Science.gov (United States)

    Priyadarsini, K Indira

    2013-01-01

    Curcumin, a polyphenolic natural product, exhibits therapeutic activity against a number of diseases, attributed mainly to its chemical structure and unique physical, chemical, and biological properties. It is a diferuloyl methane molecule [1,7-bis (4-hydroxy-3- methoxyphenyl)-1,6-heptadiene-3,5-dione)] containing two ferulic acid residues joined by a methylene bridge. It has three important functionalities: an aromatic o-methoxy phenolic group, α, β-unsaturated β-diketo moiety and a seven carbon linker. Extensive research in the last two decades has provided evidence for the role of these different functional groups in its crucial biological activities. A few highlights of chemical structural features associated with the biological activity of curcumin are: The o-methoxyphenol group and methylenic hydrogen are responsible for the antioxidant activity of curcumin, and curcumin donates an electron/ hydrogen atom to reactive oxygen species. Curcumin interacts with a number of biomolecules through non-covalent and covalent binding. The hydrogen bonding and hydrophobicity of curcumin, arising from the aromatic and tautomeric structures along with the flexibility of the linker group are responsible for the non-covalent interactions. The α, β-unsaturated β-diketone moiety covalently interacts with protein thiols, through Michael reaction. The β-diketo group forms chelates with transition metals, there by reducing the metal induced toxicity and some of the metal complexes exhibit improved antioxidant activity as enzyme mimics. New analogues with improved activity are being developed with modifications on specific functional groups of curcumin. The physico-chemical and structural features associated with some of the biological activities of curcumin and important analogues are summarized in this article. PMID:23116315

  1. Chemical compatibility of structural materials in alkali metals

    International Nuclear Information System (INIS)

    The objectives of this task are to (a) evaluate the chemical compatibility of structural alloys such as V-5 wt.%Cr-5 wt.%Ti alloy and Type 316 stainless steel for application in liquid alkali metals such as lithium and sodium-78 wt.% potassium (NaK) at temperatures in the range that are of interest for International Thermonuclear Experimental Reactor (ITER); (b) evaluate the transfer of nonmetallic elements such as oxygen, nitrogen, carbon, and hydrogen between structural materials and liquid metals; and (c) evaluate the effects of such transfers on the mechanical and microstructural characteristics of the materials for long-term service in liquid-metal-environments

  2. Design of LTCC-based Ceramic Structure for Chemical Microreactor

    Directory of Open Access Journals (Sweden)

    D. Belavic

    2012-04-01

    Full Text Available The design of ceramic chemical microreactor for the production of hydrogen needed in portable polymer-electrolyte membrane (PEM fuel cells is presented. The microreactor was developed for the steam reforming of liquid fuels with water into hydrogen. The complex three-dimensional ceramic structure of the microreactor includes evaporator(s, mixer(s, reformer and combustor. Low-temperature co-fired ceramic (LTCC technology was used to fabricate the ceramic structures with buried cavities and channels, and thick-film technology was used to make electrical heaters, temperature sensors and pressure sensors. The final 3D ceramic structure consists of 45 LTCC tapes. The dimensions of the structure are 75 × 41 × 9 mm3 and the weight is about 73 g.

  3. CHEM-PATH-TRACKER: An automated tool to analyze chemical motifs in molecular structures.

    Science.gov (United States)

    Ribeiro, João V; Cerqueira, N M F S A; Fernandes, Pedro A; Ramos, Maria J

    2014-07-01

    In this article, we propose a method for locating functionally relevant chemical motifs in protein structures. The chemical motifs can be a small group of residues or structure protein fragments with highly conserved properties that have important biological functions. However, the detection of chemical motifs is rather difficult because they often consist of a set of amino acid residues separated by long, variable regions, and they only come together to form a functional group when the protein is folded into its three-dimensional structure. Furthermore, the assemblage of these residues is often dependent on non-covalent interactions among the constituent amino acids that are difficult to detect or visualize. To simplify the analysis of these chemical motifs and give access to a generalized use for all users, we developed chem-path-tracker. This software is a VMD plug-in that allows the user to highlight and reveal potential chemical motifs requiring only a few selections. The analysis is based on atoms/residues pair distances applying a modified version of Dijkstra's algorithm, and it makes possible to monitor the distances of a large pathway, even during a molecular dynamics simulation. This tool turned out to be very useful, fast, and user-friendly in the performed tests. The chem-path-tracker package is distributed as an independent platform and can be found at http://www.fc.up.pt/PortoBioComp/database/doku.php?id=chem-path-tracker. PMID:24775806

  4. Structured Analysis - IDEF0

    DEFF Research Database (Denmark)

    Larsen, Michael Holm

    1999-01-01

    This note introduces the IDEF0 modelling language (semantics and syntax), and associated rules and techniques, for developing structured graphical representations of a system or enterprise. Use of this standard for IDEF0 permits the construction of models comprising system functions (activities......, actions, processes, operations), functional relationships, and data (information or objects) that support systems integration. An IDEF0 model is domain specific in the sense that purpose, viewpoint and context must be identified in the model. The IDEF0 modelling language is recommended for projects...... for Integration Definition for Function Modelling (IDEF0). I.e. the Draft Federal Information Processing Standards Publication 183, 1993, December 21, Announcing the Standard for Integration Definition for Function Modelling (IDEF0)....

  5. Chemical and physical structures of proteinoids and related polyamino acids

    Science.gov (United States)

    Mita, Hajime; Kuwahara, Yusuke; Nomoto, Shinya

    Studies of polyamino acid formation pathways in the prebiotic condition are important for the study of the origins of life. Several pathways of prebiotic polyamino acid formation have been reported. Heating of monoammonium malate [1] and heating of amino acids in molten urea [2] are important pathways of the prebiotic peptide formation. The former case, globular structure called proteinoid microsphere is formed in aqueous conditions. The later case, polyamino acids are formed from unrestricted amino acid species. Heating of aqueous aspargine is also interesting pathway for the prebiotic polyamino acid formation, because polyamino acid formation proceeds in aqueous condition [3]. In this study, we analyzed the chemical structure of the proteinoids and related polyamino acids formed in the above three pathways using with mass spectrometer. In addition, their physical structures are analyzed by the electron and optical microscopes, in order to determine the self-organization abilities. We discuss the relation between the chemical and the physical structures for the origins of life. References [1] Harada, K., J. Org. Chem., 24, 1662 (1959), Fox, S. W., Harada, K., and Kendrick, J., Science, 129, 1221 (1959). [2] Terasaki, M., Nomoto, S., Mita, H., and Shimoyama, A., Chem. Lett., 480 (2002), Mita, H., Nomoto, S., Terasaki, M., Shimoyama, A., and Yamamoto, Y., Int. J. Astrobiol., 4, 145 (2005). [3] Kovacs, K and Nagy, H., Nature, 190, 531 (1961), Munegumi, T., Tanikawa, N., Mita, H. and Harada, K., Viva Origino, 22, 109 (1994).

  6. Chemical structure of odorants and perceptual similarity in ants.

    Science.gov (United States)

    Bos, Nick; d'Ettorre, Patrizia; Guerrieri, Fernando J

    2013-09-01

    Animals are often immersed in a chemical world consisting of mixtures of many compounds rather than of single substances, and they constantly face the challenge of extracting relevant information out of the chemical landscape. To this purpose, the ability to discriminate among different stimuli with different valence is essential, but it is also important to be able to generalise, i.e. to treat different but similar stimuli as equivalent, as natural variation does not necessarily affect stimulus valence. Animals can thus extract regularities in their environment and make predictions, for instance about distribution of food resources. We studied perceptual similarity of different plant odours by conditioning individual carpenter ants to one odour, and subsequently testing their response to another, structurally different odour. We found that asymmetry in generalisation, where ants generalise from odour A to B, but not from B to A, is dependent on both chain length and functional group. By conditioning ants to a binary mixture, and testing their reaction to the individual components of the mixture, we show that overshadowing, where parts of a mixture are learned better than others, is rare. Additionally, generalisation is dependent not only on the structural similarity of odorants, but also on their functional value, which might play a crucial role. Our results provide insight into how ants make sense of the complex chemical world around them, for example in a foraging context, and provide a basis with which to investigate the neural mechanisms behind perceptual similarity. PMID:23685976

  7. Chemical structure of odorants and perceptual similarity in ants.

    Science.gov (United States)

    Bos, Nick; d'Ettorre, Patrizia; Guerrieri, Fernando J

    2013-09-01

    Animals are often immersed in a chemical world consisting of mixtures of many compounds rather than of single substances, and they constantly face the challenge of extracting relevant information out of the chemical landscape. To this purpose, the ability to discriminate among different stimuli with different valence is essential, but it is also important to be able to generalise, i.e. to treat different but similar stimuli as equivalent, as natural variation does not necessarily affect stimulus valence. Animals can thus extract regularities in their environment and make predictions, for instance about distribution of food resources. We studied perceptual similarity of different plant odours by conditioning individual carpenter ants to one odour, and subsequently testing their response to another, structurally different odour. We found that asymmetry in generalisation, where ants generalise from odour A to B, but not from B to A, is dependent on both chain length and functional group. By conditioning ants to a binary mixture, and testing their reaction to the individual components of the mixture, we show that overshadowing, where parts of a mixture are learned better than others, is rare. Additionally, generalisation is dependent not only on the structural similarity of odorants, but also on their functional value, which might play a crucial role. Our results provide insight into how ants make sense of the complex chemical world around them, for example in a foraging context, and provide a basis with which to investigate the neural mechanisms behind perceptual similarity.

  8. Facile chemical synthesis and structure characterization of copper molybdate nanoparticles

    Science.gov (United States)

    Rahimi-Nasrabadi, Mehdi; Pourmortazavi, Seied Mahdi; Khalilian-Shalamzari, Morteza

    2015-03-01

    Experimental parameters of a synthesis route were optimized by Taguchi robust design for the facile and controllable synthesis of copper molybdate nanoparticles. CuMoO4 nanoparticles were synthesized by chemical precipitation followed by hydrothermal process. Effects of different parameters of synthesis procedure, i.e. concentrations of both reagents, copper feeding flow rate and temperature of reactor on the particle size of prepared copper molybdate nanoparticles were investigated. The results of statistical optimization revealed that the size of copper molybdate particles is dependent on the procedure variables involving copper concentrations, flow rate and temperature of the reactor; while, molybdate concentration has a no considerable role in determining the size of CuMoO4 particles. Based on the results obtained by statistical optimization process, the nanoparticles of copper molybdate were prepared and then their structure and chemical composition were characterized by various techniques, i.e. SEM, TEM, XRD, EDX, FT-IR, UV-Vis and photoluminescence spectroscopy.

  9. The double-layered chemical structure in DB white dwarfs

    CERN Document Server

    Althaus, L G

    2004-01-01

    We study the structure and evolution of white dwarf stars with helium-rich atmospheres (DB) in a self-consistent way with the predictions of time-dependent element diffusion. Our treatment of diffusion includes gravitational settling and chemical and thermal diffusion. OPAL radiative opacities for arbitrary metallicity and carbon-and oxygen-rich compositions are employed. Emphasis is placed on the evolution of the diffusion-modeled double-layered chemical structure. This structure, which is characterized by a pure helium envelope atop an intermediate remnant shell rich in helium, carbon and oxygen, is expected for pulsating DB white dwarfs, assuming that they are descendants of hydrogen-deficient PG1159 post-AGB stars. We find that, depending on the stellar mass, if DB white dwarf progenitors are formed with a helium content smaller than \\approx 10^-3 M_*, a single-layered configuration is expected to emerge during the DB pulsation instability strip. We also explore the consequences of diffusively evolving ch...

  10. Clustering and rule-based classifications of chemical structures evaluated in the biological activity space.

    Science.gov (United States)

    Schuffenhauer, Ansgar; Brown, Nathan; Ertl, Peter; Jenkins, Jeremy L; Selzer, Paul; Hamon, Jacques

    2007-01-01

    Classification methods for data sets of molecules according to their chemical structure were evaluated for their biological relevance, including rule-based, scaffold-oriented classification methods and clustering based on molecular descriptors. Three data sets resulting from uniformly determined in vitro biological profiling experiments were classified according to their chemical structures, and the results were compared in a Pareto analysis with the number of classes and their average spread in the profile space as two concurrent objectives which were to be minimized. It has been found that no classification method is overall superior to all other studied methods, but there is a general trend that rule-based, scaffold-oriented methods are the better choice if classes with homogeneous biological activity are required, but a large number of clusters can be tolerated. On the other hand, clustering based on chemical fingerprints is superior if fewer and larger classes are required, and some loss of homogeneity in biological activity can be accepted.

  11. Current trends of the development of chemical analysis

    Directory of Open Access Journals (Sweden)

    Rema Matakova

    2014-12-01

    Full Text Available This paper presents dynamics of the development of all stages of chemical analysis during last 15 years. The ways of the quality improvement of chemical analysis and its considerable advancement into the field of trace concentrations of substances are shown. Features of development of analytical methods, modern techniques for concentration and separation of substances, as well as chemomerrical processing of results are analyzed. Huge importance of computerization and automation of the analysis is shown.

  12. Effects of structural differences on the NMR chemical shifts in isostructural dipeptides.

    Science.gov (United States)

    Altheimer, Benjamin D; Mehta, Manish A

    2014-04-10

    Porous crystalline dipeptides have gained recent attention for their potential as gas-storage materials. Within this large class is a group of dipeptides containing alanine, valine, and isoleucine with very similar crystal structures. We report the (13)C (carbonyl and Cα) and (15)N (amine and amide) solid-state NMR isotropic chemical shifts in a series of seven such isostructural porous dipeptides as well as shift tensor data for the carbonyl and amide sites. Using their known crystal structures and aided by ab initio quantum chemical calculations for the resonance assignments, we elucidate trends relating local structure, hydrogen-bonding patterns, and chemical shift. We find good correlation between the backbone dihedral angles and the Cα1 and Cα2 shifts. For the C1 shift tensor, the δ11 value shifts downfield as the hydrogen-bond distance increases, δ22 shifts upfield, and δ33 shows little variation. The C2 shift tensor shows no appreciable correlation with structural parameters. For the N2 tensor, δ11 shows little dependence on the hydrogen-bond length, whereas δ22 and δ33 both show a decrease in shielding as the hydrogen bond shortens. Our analysis teases apart some, but not all, structural contributors to the observed differences the solid-state NMR chemical shifts.

  13. Effects of chemical treatments on hemp fibre structure

    Science.gov (United States)

    Kabir, M. M.; Wang, H.; Lau, K. T.; Cardona, F.

    2013-07-01

    In this study, hemp fibres were treated with alkali, acetyl and silane chemicals. Fibre constituents such as cellulose, hemicellulose and lignin constituents were separated from treated fibres. The chemical and thermal influences of these constituents on the treated fibres were examined by using scanning electron microscope (SEM), fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Experimental results revealed that, hemicellulose was degraded faster than that of cellulose and lignin. Cellulose exhibited better thermal stability and lignin was degraded in a wide range of temperatures. The hydrophilic nature of the fibres was predominantly caused by the presence of hemicellulose and then lignin constituents. Hemicellulose and lignin were mostly removed by the alkalisation with higher concentrations of NaOH, followed by acetylation. Silane treatment could not remove the hemicellulose and lignin, rather this treatment facilitated coupling with the fibre constituents.

  14. Chemical structures and thermochemical properties of bagasse lignin

    Institute of Scientific and Technical Information of China (English)

    Wu Shu-bin; Guo Yi-li; Wang Shao-guang; Li Meng-shi

    2006-01-01

    The chemical structures of bagasse EMAL (enzymatic hydrolysis/mild acidolysis lignin) were revealed quantitatively with 31P-NMR, DFRC (derivatization followed by reductive cleavage). The thermochemical characteristics of bagasse and bagasse EMAL were evaluated with thermogravimetry. The results show that bagasse EMAL is mainly formed by the phenolic hydroxyl group of guaiacyl and syringyl units. The DBDO content in bagasse EMAL was found to be 0.180 mmol·g-1. The decomposition characteristics of bagasse EMAL under elevated temperature were much different from that of bagasse.

  15. Inclusion compound of vitamin B6 in {beta}-CD. Physico-chemical and structural investigations

    Energy Technology Data Exchange (ETDEWEB)

    Borodi, Gheorghe; Kacso, Irina; Farcas, Sorin I; Bratu, Ioan, E-mail: ioan.bratu@itim-cj.r [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania)

    2009-08-01

    Structural and physico-chemical characterization of supramolecular assembly of vitamin B6 with {beta}-cyclodextrin ({beta}-CD) prepared by different methods (kneading, co-precipitation and freeze-drying) has been performed by using several spectroscopic techniques (FTIR, {sup 1}H NMR, UV-Vis), powder X-ray diffraction and DSC in order to evidence the inclusion compound formation. An analysis of the chemical shifts observed in the {sup 1}H-NMR spectra and of the vibrational frequency shifts led to the tentative conclusion that the vitamin B6 probably enters the cyclodextrin torus when forming the {beta}-CD-vitamin B6 inclusion complex.

  16. Inclusion compound of vitamin B6 in β-CD. Physico-chemical and structural investigations

    Science.gov (United States)

    Borodi, Gheorghe; Kacso, Irina; Farcaş, Sorin I.; Bratu, Ioan

    2009-08-01

    Structural and physico-chemical characterization of supramolecular assembly of vitamin B6 with β-cyclodextrin (β-CD) prepared by different methods (kneading, co-precipitation and freeze-drying) has been performed by using several spectroscopic techniques (FTIR, 1H NMR, UV-Vis), powder X-ray diffraction and DSC in order to evidence the inclusion compound formation. An analysis of the chemical shifts observed in the 1H-NMR spectra and of the vibrational frequency shifts led to the tentative conclusion that the vitamin B6 probably enters the cyclodextrin torus when forming the β-CD-vitamin B6 inclusion complex.

  17. Hybrid chemical and nondestructive analysis technique

    International Nuclear Information System (INIS)

    A hybrid chemical/NDA technique has been applied at the Los Alamos National Laboratory to the assay of plutonium in ion-exchange effluents. Typical effluent solutions contain low concentrations of plutonium and high concentrations of americium. A simple trioctylphosphine oxide (TOPO) separation can remove 99.9% of the americium. The organic phase that contains the separated plutonium can be accurately assayed by monitoring the uranium L x-ray intensities

  18. Hybrid chemical and nondestructive-analysis technique

    Energy Technology Data Exchange (ETDEWEB)

    Hsue, S.T.; Marsh, S.F.; Marks, T.

    1982-01-01

    A hybrid chemical/NDA technique has been applied at the Los Alamos National Laboratory to the assay of plutonium in ion-exchange effluents. Typical effluent solutions contain low concentrations of plutonium and high concentrations of americium. A simple trioctylphosphine oxide (TOPO) separation can remove 99.9% of the americium. The organic phase that contains the separated plutonium can be accurately assayed by monitoring the uranium L x-ray intensities.

  19. EFFECT OF CHEMICAL STRUCTURE OF POLYCARBONATES ON ENTANGLEMENT SPACING

    Institute of Scientific and Technical Information of China (English)

    Wei Ning; Wen-xiang Zhu; Bao-qing Zhang; Chun-cheng Li; Chen-yang Liu; Du-jin Wang

    2012-01-01

    The master curves of a series of aliphatic polycarbonates (APCs) with different lengths of methylene segments in the repeat unit were obtained by dynamic rheological measurements.The plateau modulus and entanglement molecular weight were determined and cross-checked by different methods.Though having distinct difference in chemical structure of repeat units,both APCs and bisphenol-A polycarbonates have the similar entanglement weight and entanglement spacing.On the other side,the plateau modulus decreases with increasing the length of the side group of atiphatic polycarbonates with different side-chain lengths in the literature.The packing length model can explain the relationship between chain structure and entanglements.

  20. Avogadro: an advanced semantic chemical editor, visualization, and analysis platform

    Directory of Open Access Journals (Sweden)

    Hanwell Marcus D

    2012-08-01

    Full Text Available Abstract Background The Avogadro project has developed an advanced molecule editor and visualizer designed for cross-platform use in computational chemistry, molecular modeling, bioinformatics, materials science, and related areas. It offers flexible, high quality rendering, and a powerful plugin architecture. Typical uses include building molecular structures, formatting input files, and analyzing output of a wide variety of computational chemistry packages. By using the CML file format as its native document type, Avogadro seeks to enhance the semantic accessibility of chemical data types. Results The work presented here details the Avogadro library, which is a framework providing a code library and application programming interface (API with three-dimensional visualization capabilities; and has direct applications to research and education in the fields of chemistry, physics, materials science, and biology. The Avogadro application provides a rich graphical interface using dynamically loaded plugins through the library itself. The application and library can each be extended by implementing a plugin module in C++ or Python to explore different visualization techniques, build/manipulate molecular structures, and interact with other programs. We describe some example extensions, one which uses a genetic algorithm to find stable crystal structures, and one which interfaces with the PackMol program to create packed, solvated structures for molecular dynamics simulations. The 1.0 release series of Avogadro is the main focus of the results discussed here. Conclusions Avogadro offers a semantic chemical builder and platform for visualization and analysis. For users, it offers an easy-to-use builder, integrated support for downloading from common databases such as PubChem and the Protein Data Bank, extracting chemical data from a wide variety of formats, including computational chemistry output, and native, semantic support for the CML file format

  1. CODSTRAN: Composite durability structural analysis

    Science.gov (United States)

    Chamis, C. C.; Smith, G. T.

    1978-01-01

    CODSTRAN (COmposite Durability STRuctural ANalysis) is an integrated computer program being developed for the prediction of defect growth and fracture of composite structures subjected to service loads and environments. CODSTRAN is briefly described with respect to organization, capabilities and present status. Application of CODSTRAN current capability to a flat composite laminate with a center slit which was subjected to axial tension loading predicted defect growth which is in good agreement with C-scan ultrasonic test records.

  2. Method for fractional solid-waste sampling and chemical analysis

    DEFF Research Database (Denmark)

    Riber, Christian; Rodushkin, I.; Spliid, Henrik;

    2007-01-01

    Chemical characterization of solid waste is a demanding task due to the heterogeneity of the waste. This article describes how 45 material fractions hand-sorted from Danish household waste were subsampled and prepared for chemical analysis of 61 substances. All material fractions were subject...

  3. EDXRF for non-destructive chemical analysis

    International Nuclear Information System (INIS)

    One of the non-destructive methods used for the identification and verification of metals is by the energy-dispersive X-ray fluorescence (EDXRF) technique. EDXRF analysis provides several important advantages such as simultaneous determination of the elements present, enable to analyse a very wide concentration range, fast analysis with no sample preparation. The paper shows how this technique is developed and applied in the identification and verification of different grades of stainless steels and also precious metals analysis. (Author)

  4. Ultrastructural Analysis of Urinary Stones by Microfocus Computed Tomography and Comparison with Chemical Analysis

    Directory of Open Access Journals (Sweden)

    Tolga Karakan

    2016-06-01

    Full Text Available Objective: To investigate the ultra-structure of urinary system stones using micro-focus computed tomography (MCT, which makes non-destructive analysis and to compare with wet chemical analysis. Methods: This study was carried out at the Ankara Train­ing and Research hospital. Renal stones, removed from 30 patients during percutaneous nephrolithotomy (PNL surgery, were included in the study. The stones were blindly evaluated by the specialists with MCT and chemi­cal analysis. Results: The comparison of the stone components be­tween chemical analysis and MCT, showed that the rate of consistence was very low (p0.05. It was also seen that there was no significant relation between its 3D structure being heterogeneous or homogenous. Conclusion: The stone analysis with MCT is a time con­suming and costly method. This method is useful to un­derstand the mechanisms of stone formation and an im­portant guide to develop the future treatment modalities.

  5. Tribology analysis of chemical-mechanical polishing

    Energy Technology Data Exchange (ETDEWEB)

    Runnels, S.R.; Eyman, L.M. (Sematech, Austin, TX (United States))

    1994-06-01

    To better understand the variation of material removal rate on a wafer during chemical-mechanical polishing (CMP), knowledge of the stress distribution on the wafer surface is required. The difference in wafer-surface stress distributions could be considerable depending on whether or not the wafer hydroplanes during polishing. This study analyzes the fluid film between the wafer and pad and demonstrates that hydroplaning is possible for standard CMP processes. The importance of wafer curvature, slurry viscosity, and rotation speed on the thickness of the fluid film is also demonstrated.

  6. On the Mathematical Structure of Balanced Chemical Reaction Networks Governed by Mass Action Kinetics

    OpenAIRE

    der Schaft, Arjan van; Rao, Shodhan; Jayawardhana, Bayu

    2011-01-01

    Motivated by recent progress on the interplay between graph theory, dynamics, and systems theory, we revisit the analysis of chemical reaction networks described by mass action kinetics. For reaction networks possessing a thermodynamic equilibrium we derive a compact formulation exhibiting at the same time the structure of the complex graph and the stoichiometry of the network, and which admits a direct thermodynamical interpretation. This formulation allows us to easily characterize the set ...

  7. Structural, optical and electrical properties of chemically deposited nonstoichiometric copper indium diselenide films

    Indian Academy of Sciences (India)

    R H Bari; L A Patil; P P Patil

    2006-10-01

    Thin films of copper indium diselenide (CIS) were prepared by chemical bath deposition technique onto glass substrate at temperature, 60°C. The studies on composition, morphology, optical absorption, electrical conductivity and structure of the films were carried out and discussed. Characterization included X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray analysis (EDAX) and absorption spectroscopy. The results are discussed and interpreted.

  8. Structural analysis of aligned RNAs.

    Science.gov (United States)

    Voss, Björn

    2006-01-01

    The knowledge about classes of non-coding RNAs (ncRNAs) is growing very fast and it is mainly the structure which is the common characteristic property shared by members of the same class. For correct characterization of such classes it is therefore of great importance to analyse the structural features in great detail. In this manuscript I present RNAlishapes which combines various secondary structure analysis methods, such as suboptimal folding and shape abstraction, with a comparative approach known as RNA alignment folding. RNAlishapes makes use of an extended thermodynamic model and covariance scoring, which allows to reward covariation of paired bases. Applying the algorithm to a set of bacterial trp-operon leaders using shape abstraction it was able to identify the two alternating conformations of this attenuator. Besides providing in-depth analysis methods for aligned RNAs, the tool also shows a fairly well prediction accuracy. Therefore, RNAlishapes provides the community with a powerful tool for structural analysis of classes of RNAs and is also a reasonable method for consensus structure prediction based on sequence alignments. RNAlishapes is available for online use and download at http://rna.cyanolab.de. PMID:17020924

  9. Synthesis, crystal structure analysis, spectral characterization, quantum chemical calculations, antioxidant and antimicrobial activity of 3-(4-chlorophenyl)-3a,4,7,7a-tetrahydro-4,7-methanobenzo[d]isoxazole

    Science.gov (United States)

    Eryılmaz, Serpil; Gül, Melek; İnkaya, Ersin; İdil, Önder; Özdemir, Namık

    2016-10-01

    In this paper, 3-(4-chlorophenyl)-3a,4,7,7a-tetrahydro-4,7-methanobenzo[d]isoxazole was synthesized via 1,3 dipolar cycloaddition, characterized by spectroscopic analysis such as FT-IR, 1H NMR, 13C NMR, UV-Vis, LC-MS/MS, Elemental Analysis, and X-ray Single Crystal diffraction technique. The Density Functional Theory (DFT/B3LYP) method with 6-311G(d,p) basis set in the ground state was applied for quantum chemical calculations and molecular geometric parameters of the compound were compared with the X-ray analysis results. FT-IR, NMR and UV-Vis spectral analysis were analysed to determine the compliance with the vibrational frequencies, 1H NMR and 13C NMR chemical shifts and absorption wavelength values. The frontier molecular orbitals (FMOs), some global reactivity descriptors, molecular electrostatic potential (MEP), thermodynamic properties, non-linear optical (NLO) behaviour of the compound were examined with the same method in gas phase, theoretically. Moreover, antioxidant activity was determined with three different methods - DPPH radical scavenging, reducing and metal chelating, antimicrobial activity were carried out with Gram positive, Gram negative and Eukaryote for the title compound.

  10. Chemical equilibrium analysis of dry hydrogen combustion

    International Nuclear Information System (INIS)

    The present work is based on a thermo-chemical equilibrium model for studying the effect of combustion of hydrogen during postulated accident scenarios in nuclear reactor containments. This model is based on the method of element potentials which seeks to minimize the free energy of the system. The condition on internal energy balance is imposed as a constraint during the minimization process. Another simplified model purely based on the internal energy balance has also been implemented to investigate the isolated impact of free energy and the conditions under which it becomes dominant. The two models have been used to extract final pressures for a wide range of initial conditions and mixture compositions that are typically found during accident scenarios. In the absence of hydrogen combustion experimental data, such models will become important for laying down a first estimate on the possible outcomes. (author)

  11. Regioisomers of octanoic acid-containing structured triacylglycerols analyzed by tandem mass spectrometry using ammonia negative ion chemical ionization

    DEFF Research Database (Denmark)

    Kurvinen, J.P.; Mu, Huiling; Kallio, H.;

    2001-01-01

    Tandem mass spectrometry based on ammonia negative ion chemical ionization and sample introduction via direct exposure probe was applied to analysis of regioisomeric structures of octanoic acid containing structured triacylglycerols (TAG) of type MML, MLM, MLL, and LML (M, medium-chain fatty acid...

  12. Monomeric and dimeric structures analysis and spectroscopic characterization of 3,5-difluorophenylboronic acid with experimental (FT-IR, FT-Raman, 1H and 13C NMR, UV) techniques and quantum chemical calculations

    Science.gov (United States)

    Karabacak, Mehmet; Kose, Etem; Atac, Ahmet; Asiri, Abdullah M.; Kurt, Mustafa

    2014-01-01

    The spectroscopic properties of 3,5-difluorophenylboronic acid (3,5-DFPBA, C6H3F2B(OH)2) were investigated by FT-IR, FT-Raman UV-Vis, 1H and 13C NMR spectroscopic techniques. FT-IR (4000-400 cm-1) and FT-Raman spectra (3500-10 cm-1) in the solid phase and 1H and 13C NMR spectra in DMSO solution were recorded. The UV spectra that dissolved in ethanol and water were recorded in the range of 200-400 nm for each solution. The structural and spectroscopic data of the molecule have been obtained for possible three conformers from DFT (B3LYP) with 6-311++G(d,p) basis set calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. Hydrogen-bonded dimer of title molecule, optimized by counterpoise correction, was also studied B3LYP at the 6-311++G(d,p) level and the effects of molecular association through O-H⋯O hydrogen bonding have been discussed. 1H and 13C NMR chemical shifts were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, oscillator strength, wavelengths, HOMO and LUMO energies, were performed by time-dependent density functional theory (TD-DFT) results complements with the experimental findings. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (OPDOS) diagrams analysis were presented. The effects due to the substitutions of boric acid group and halogen were investigated. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), nonlinear optical properties (NLO) and thermodynamic features were performed.

  13. Integrating chemical footprinting data into RNA secondary structure prediction.

    Directory of Open Access Journals (Sweden)

    Kourosh Zarringhalam

    Full Text Available Chemical and enzymatic footprinting experiments, such as shape (selective 2'-hydroxyl acylation analyzed by primer extension, yield important information about RNA secondary structure. Indeed, since the [Formula: see text]-hydroxyl is reactive at flexible (loop regions, but unreactive at base-paired regions, shape yields quantitative data about which RNA nucleotides are base-paired. Recently, low error rates in secondary structure prediction have been reported for three RNAs of moderate size, by including base stacking pseudo-energy terms derived from shape data into the computation of minimum free energy secondary structure. Here, we describe a novel method, RNAsc (RNA soft constraints, which includes pseudo-energy terms for each nucleotide position, rather than only for base stacking positions. We prove that RNAsc is self-consistent, in the sense that the nucleotide-specific probabilities of being unpaired in the low energy Boltzmann ensemble always become more closely correlated with the input shape data after application of RNAsc. From this mathematical perspective, the secondary structure predicted by RNAsc should be 'correct', in as much as the shape data is 'correct'. We benchmark RNAsc against the previously mentioned method for eight RNAs, for which both shape data and native structures are known, to find the same accuracy in 7 out of 8 cases, and an improvement of 25% in one case. Furthermore, we present what appears to be the first direct comparison of shape data and in-line probing data, by comparing yeast asp-tRNA shape data from the literature with data from in-line probing experiments we have recently performed. With respect to several criteria, we find that shape data appear to be more robust than in-line probing data, at least in the case of asp-tRNA.

  14. Permeability and chemical analysis of aromatic polyamide based membranes exposed to sodium hypochlorite

    OpenAIRE

    Ettori, Axel; Gaudichet-Maurin, Emmanuelle; Schrotter, Jean-Christophe; Aimar, Pierre; Causserand, Christel

    2011-01-01

    In this study, a cross-linked aromatic polyamide based reverse osmosis membrane was exposed to variable sodium hypochlorite ageing conditions (free chlorine concentration, solution pH) and the resulting evolutions of membrane surface chemical and structural properties were monitored. Elemental and surface chemical analysis performed using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR), showed that chlorine is essentially incorporated on the polyamide...

  15. Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

    Science.gov (United States)

    Lee, H. V.; Hamid, S. B. A.; Zain, S. K.

    2014-01-01

    Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate's application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein. PMID:25247208

  16. Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

    Directory of Open Access Journals (Sweden)

    H. V. Lee

    2014-01-01

    Full Text Available Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate’s application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein.

  17. Chemical aspects of nuclear methods of analysis

    International Nuclear Information System (INIS)

    This final report includes papers which fall into three general areas: development of practical pre-analysis separation techniques, uranium/thorium separation from other elements for analytical and processing operations, and theory and mechanism of separation techniques. A separate abstract was prepared for each of the 9 papers

  18. Structural Analysis of Plate Based Tensegrity Structures

    DEFF Research Database (Denmark)

    Hald, Frederik; Kirkegaard, Poul Henning; Damkilde, Lars

    2013-01-01

    Plate tensegrity structures combine tension cables with a cross laminated timber plate and can then form e.g. a roof structure. The topology of plate tensegrity structures is investigated through a parametric investigation. Plate tensegrity structures are investigated, and a method for...... determination of the structures pre-stresses is used. A parametric investigation is performed to determine a more optimized form of the plate based tensegrity structure. Conclusions of the use of plate based tensegrity in civil engineering and further research areas are discussed....

  19. Structural Analysis of Complex Networks

    CERN Document Server

    Dehmer, Matthias

    2011-01-01

    Filling a gap in literature, this self-contained book presents theoretical and application-oriented results that allow for a structural exploration of complex networks. The work focuses not only on classical graph-theoretic methods, but also demonstrates the usefulness of structural graph theory as a tool for solving interdisciplinary problems. Applications to biology, chemistry, linguistics, and data analysis are emphasized. The book is suitable for a broad, interdisciplinary readership of researchers, practitioners, and graduate students in discrete mathematics, statistics, computer science,

  20. Stereological analysis of spatial structures

    DEFF Research Database (Denmark)

    Hansen, Linda Vadgård

    The thesis deals with stereological analysis of spatial structures. One area of focus has been to improve the precision of well-known stereological estimators by including information that is available via automatic image analysis. Furthermore, the thesis presents a stochastic model for star......-shaped three-dimensional objects using the radial function. It appears that the model is highly fleksiblel in the sense that it can be used to describe an object with arbitrary irregular surface. Results on the distribution of well-known local stereological volume estimators are provided....

  1. Chemical diversity among populations of Mikania micrantha: geographic mosaic structure and herbivory.

    Science.gov (United States)

    Bravo-Monzón, Angel Eliezer; Ríos-Vásquez, Eunice; Delgado-Lamas, Guillermo; Espinosa-García, Francisco J

    2014-01-01

    Populations of the same species vary in their secondary metabolite content. This variation has been attributed to biotic and abiotic environmental conditions as well as to historical factors. Some studies have focused on the geographic variation of chemical diversity in plant populations, but whether this structure conforms to a central-marginal model or a mosaic pattern remains unclear. Furthermore, assessing the chemical diversity of invasive plants in their native distribution facilitates the understanding of their relationships with natural enemies. We examined the geographic variation of chemical diversity in Mexican populations of the bittervine weed Mikania micrantha and its relationship to herbivore damage. The foliar volatile terpenoid blend was analyzed in 165 individuals of 14 populations in the Pacific and Gulf of Mexico tropical watersheds. A cluster analysis grouped individuals with similar terpenoid blends into 56 compositional types. Chemical diversity was measured using the number of compounds and their concentration within the blends for individuals, and the number and frequency of compositional types for populations. A stepwise multiple regression analysis performed with geographic, climatic, and chemical diversity variables explained herbivore damage. However, population-level chemical diversity was the only variable found to be significant (β = -0.79, P = 0.042) in the model (R(2) = 0.89). A Mantel test using Euclidean distances did not indicate any separation by geographic origin; however, four barriers were identified using Monmonier's algorithm. We conclude that variation in population-level chemical diversity follows a mosaic pattern in which geographic factors (i.e., natural barriers) have some effect and that variation is also associated with the local intensity of herbivore attack. PMID:23942983

  2. Structural and Optical Properties of Chemical Bath Deposited Silver Oxide Thin Films: Role of Deposition Time

    Directory of Open Access Journals (Sweden)

    A. C. Nwanya

    2013-01-01

    Full Text Available Silver oxide thin films were deposited on glass substrates at a temperature of 50°C by chemical bath deposition technique under different deposition times using pure AgNO3 precursor and triethanolamine as the complexing agent. The chemical analysis based on EDX technique shows the presence of Ag and O at the appropriate energy levels. The morphological features obtained from SEM showed that the AgxO structures varied as the deposition time changes. The X-ray diffraction showed the peaks of Ag2O and AgO in the structure. The direct band gap and the refractive index increased as the deposition time increased and was in the range of 1.64–1.95 eV and 1.02–2.07, respectively. The values of the band gap and refractive index obtained indicate possible applications in photovoltaic and photothermal systems.

  3. Understanding the chemical and structural transformations of lignin macromolecule during torrefaction

    International Nuclear Information System (INIS)

    Highlights: • The terrified bamboo has a high energy yield of 85.7% and a HHV of 20.13 MJ/kg. • The structural changes of hemicelluloses, cellulose, and lignin were investigated. • First study on the structural transformations of lignin during torrefaction. • The mechanism of structural changes of lignin has been proposed. - Abstract: Torrefaction is an efficient method to recover energy from biomass. Herein, the characteristics (mass yield, energy yield, physical, and chemical characteristics) of torrefied bamboo at diverse temperatures (200–300 °C) were firstly evaluated by elemental analysis, XRD, and CP–MAS 13C NMR methodologies. Under an optimal condition the terrified bamboo has a relative high energy yield of 85.7% and a HHV of 20.13 MJ/kg. The chemical and structural transformations of lignin induced by thermal treatment were thoroughly investigated by FT-IR and solution-state NMR techniques (quantitative 13C NMR, 2D-HSQC, and 31P-NMR methodologies). The results highlighted the chemical reactions of the native bamboo lignins towards severe torrefaction treatments occurred, such as depolymerization, demethoxylation, bond cleavage, and condensation reactions. NMR results indicated that aryl-ether bonds (β-O-4) and p-coumaric ester in lignin were cleaved during the torrefaction process at mild conditions. The severe treatments of bamboo (275 °C and 300 °C) induced a dramatic enrichment in lignin content together with the almost complete disappearance of β-O-4, β-β, and β-5 linkages. Further analysis of the molecular weight of milled wood lignin (MWL) indicated that the average molecular weights of “torrefied MWL” were lower than those of control MWL. It is believed that understanding of the reactivity and chemical transformations of lignin during torrefaction will contribute to the integrated torrefaction mechanism

  4. Quantitative Survey and Structural Classification of Fracking Chemicals Reported in Unconventional Gas Exploitation

    Science.gov (United States)

    Elsner, Martin; Schreglmann, Kathrin

    2015-04-01

    Few technologies are being discussed in such controversial terms as hydraulic fracturing ("fracking") in the recovery of unconventional gas. Particular concern regards the chemicals that may return to the surface as a result of hydraulic fracturing. These are either "fracking chemicals" - chemicals that are injected together with the fracking fluid to optimize the fracturing performance or geogenic substances which may turn up during gas production, in the so-called produced water originating from the target formation. Knowledge about them is warranted for several reasons. (1) Monitoring. Air emissions are reported to arise from well drilling, the gas itself or condensate tanks. In addition, potential spills and accidents bear the danger of surface and shallow groundwater contaminations. Monitoring strategies are therefore warranted to screen for "indicator" substances of potential impacts. (2) Chemical Analysis. To meet these analytical demands, target substances must be defined so that adequate sampling approaches and analytical methods can be developed. (3) Transformation in the Subsurface. Identification and classification of fracking chemicals (aromatics vs. alcohols vs. acids, esters, etc.) is further important to assess the possibility of subsurface reactions which may potentially generate new, as yet unidentified transformation products. (4) Wastewater Treatment. For the same reason chemical knowledge is important for optimized wastewater treatment strategies. (5) Human and Ecosystem Health. Knowledge of the most frequent fracking chemicals is further essential for risk assessment (environmental behavior, toxicity) (6) Public Discussions. Finally, an overview of reported fracking chemicals can provide unbiased scientific into current public debates and enable critical reviews of Green Chemistry approaches. Presently, however, such information is not readily available. We aim to close this knowledge gap by providing a quantitative overview of chemical

  5. Evaluation of chemical and structural properties of germanium-carbon coatings deposited by plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Jamali, Hossein, E-mail: h.jamali@mut-es.ac.ir; Mozafarinia, Reza; Eshaghi, Akbar

    2015-10-15

    Germanium-carbon coatings were deposited on silicon and glass substrates by plasma enhanced chemical vapor deposition (PECVD) using three different flow ratios of GeH{sub 4} and CH{sub 4} precursors. Elemental analysis, structural evaluation and microscopic investigation of coatings were performed using laser-induced breakdown spectroscopy (LIBS), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM), respectively. Based on the results, the coatings exhibited a homogeneous and dense structure free of pores with a very good adhesion to substrate. The structural evaluation revealed that the germanium-carbon coatings were a kind of a Ge-rich composite material containing the amorphous and crystalline germanium and amorphous carbon with the mixture of Ge–Ge, Ge–C, C–C, Ge–H and C–H bonds. The result suggested that the amorphisation of the coatings could be increased with raising CH{sub 4}:GeH{sub 4} flow rate ratio and subsequently increasing C amount incorporated into the coating. - Highlights: • Germanium-carbon coatings were prepared by PECVD technique. • The germanium-carbon coatings were a kind of composite material. • The amorphisation of the coatings were increased with raising CH{sub 4}:GeH{sub 4} flow ratio.

  6. Airborne chemistry: acoustic levitation in chemical analysis.

    Science.gov (United States)

    Santesson, Sabina; Nilsson, Staffan

    2004-04-01

    This review with 60 references describes a unique path to miniaturisation, that is, the use of acoustic levitation in analytical and bioanalytical chemistry applications. Levitation of small volumes of sample by means of a levitation technique can be used as a way to avoid solid walls around the sample, thus circumventing the main problem of miniaturisation, the unfavourable surface-to-volume ratio. Different techniques for sample levitation have been developed and improved. Of the levitation techniques described, acoustic or ultrasonic levitation fulfils all requirements for analytical chemistry applications. This technique has previously been used to study properties of molten materials and the equilibrium shape()and stability of liquid drops. Temperature and mass transfer in levitated drops have also been described, as have crystallisation and microgravity applications. The airborne analytical system described here is equipped with different and exchangeable remote detection systems. The levitated drops are normally in the 100 nL-2 microL volume range and additions to the levitated drop can be made in the pL-volume range. The use of levitated drops in analytical and bioanalytical chemistry offers several benefits. Several remote detection systems are compatible with acoustic levitation, including fluorescence imaging detection, right angle light scattering, Raman spectroscopy, and X-ray diffraction. Applications include liquid/liquid extractions, solvent exchange, analyte enrichment, single-cell analysis, cell-cell communication studies, precipitation screening of proteins to establish nucleation conditions, and crystallisation of proteins and pharmaceuticals. PMID:14762640

  7. Black tea: chemical analysis and stability.

    Science.gov (United States)

    Li, Shiming; Lo, Chih-Yu; Pan, Min-Hsiung; Lai, Ching-Shu; Ho, Chi-Tang

    2013-01-01

    Tea is the most popular flavored and functional drink worldwide. The nutritional value of tea is mostly from the tea polyphenols that are reported to possess a broad spectrum of biological activities, including anti-oxidant properties, reduction of various cancers, inhibition of inflammation, and protective effects against diabetes, hyperlipidemia and obesity. Tea polyphenols include catechins and gallic acid in green and white teas, and theaflavins and thearubigins as well as other catechin polymers in black and oolong teas. Accurate analysis of black tea polyphenols plays a significant role in the identification of black tea contents, quality control of commercial tea beverages and extracts, differentiation of various contents of theaflavins and catechins and correlations of black tea identity and quality with biological activity, and most importantly, the establishment of the relationship between quantitative tea polyphenol content and its efficacy in animal or human studies. Global research in tea polyphenols has generated much in vitro and in vivo data rationally correlating tea polyphenols with their preventive and therapeutic properties in human diseases such as cancer, and metabolic and cardiovascular diseases etc. Based on these scientific findings, numerous tea products have been developed including flavored tea drinks, tea-based functional drinks, tea extracts and concentrates, and dietary supplements and food ingredients, demonstrating the broad applications of tea and its extracts, particularly in the field of functional food.

  8. Terahertz Chemical Analysis of Exhaled Human Breath - Broad Essay of Chemicals

    Science.gov (United States)

    Branco, Daniela R.; Fosnight, Alyssa M.; Thomas, Jessica R.; Medvedev, Ivan R.

    2013-06-01

    Approximately 3000 chemicals are thought to be present in human breath. Of these chemicals, many are considered typical of exhaled air. Yet, others can allude to different disease pathologies. The detection of chemicals in breath could have many practical purposes in medicine and provide a noninvasive means of diagnostics. We have previously reported on detection of ethanol, methanol, and acetone in exhaled human breath using a novel sub-millimeter/THz spectroscopic approach. This paper reports on our most recent study. A tentative list has been made of approximately 20 chemicals previously found in breath using other methods. Though many of these chemicals are only expressed in samples from donors with certain pathologies, at the time of this submission we are able to detect and quantitatively measure acetaldehyde and dimethyl sulfide in the breath of several healthy donors. Additional tentatively identified chemicals have been seen using this approach. This presentation will explain our experimental procedures and present our most recent results in THz breath analysis. Prospects, challenges and future plans will be outlined and discussed.

  9. X-ray chemical imaging and the electronic structure of a single nanoplatelet Ni/graphene composite.

    Science.gov (United States)

    Zhou, Chunyu; Wang, Jian; Szpunar, Jerzy A

    2014-03-01

    Chemical imaging and quantitative analysis of a single graphene nanoplatelet grown with Ni nanoparticles (Ni/graphene) has been performed by scanning transmission X-ray microscopy (STXM). Local electronic and chemical structure of Ni/graphene has been investigated by spatially resolved C, O K-edges and Ni L-edge X-ray absorption near edge structure (XANES) spectroscopy, revealing the covalent anchoring of Ni(0) on graphene. This study facilitates the understanding of the structure modification of host materials for hydrogen storage and offers a better understanding of interaction between Ni particles and graphene.

  10. Wikipedia Chemical Structure Explorer: substructure and similarity searching of molecules from Wikipedia

    OpenAIRE

    Ertl, Peter; Patiny, Luc; Sander, Thomas; Rufener, Christian; Zasso, Michaël

    2015-01-01

    Background Wikipedia, the world’s largest and most popular encyclopedia is an indispensable source of chemistry information. It contains among others also entries for over 15,000 chemicals including metabolites, drugs, agrochemicals and industrial chemicals. To provide an easy access to this wealth of information we decided to develop a substructure and similarity search tool for chemical structures referenced in Wikipedia. Results We extracted chemical structures from entries in Wikipedia an...

  11. A review of chemical gradient systems for cell analysis.

    Science.gov (United States)

    Somaweera, Himali; Ibraguimov, Akif; Pappas, Dimitri

    2016-02-11

    Microfluidic spatial and temporal gradient generators have played an important role in many biological assays such as in the analysis of wound healing, inflammation, and cancer metastasis. Chemical gradient systems can also be applied to other fields such as drug design, chemical synthesis, chemotaxis, etc. Microfluidic systems are particularly amenable to gradient formation, as the length scales used in chips enable fluid processes that cannot be conducted in bulk scale. In this review we discuss new microfluidic devices for gradient generation and applications of those systems in cell analysis.

  12. Effects of age and sex on the structural, chemical and technological characteristics of mule duck meat.

    Science.gov (United States)

    Baeza, E; Salichon, M R; Marche, G; Wacrenier, N; Dominguez, B; Culioli, J

    2000-07-01

    1. The aim of the study was to analyse the effect of age and sex on the chemical, structural and technological characteristics of mule duck meat. 2. Ten males and 10 females were weighed and slaughtered at 8, 10, 11, 12 and 13 weeks of age. Weight, pH value, colour, tenderness and juice loss of breast muscle were determined. 3. The activities of 3 enzymes (citrate synthase, beta-hydroxyacyl CoA dehydrogenase, lactate dehydrogenase) which indicate muscular metabolic activity were assayed. 4. Chemical composition (moisture, lipids, proteins, minerals, lipid and phospholipid classes, fatty acid composition) of breast muscle was analysed. 5. Fibre type, fibre type percentage and cross-sectional areas were determined using histochemistry and an image analysis system. 6. For growth performance and muscular structure, the ideal slaughter age of mule ducks is 10 weeks of age. Chemical and technological analysis indicated that muscular maturity in Pectoralis major was reached at 11 weeks of age, but, at this age, breast lipid content is high. Moreover, after 10 weeks of age, food costs rapidly increased. 7. Lastly, sexual dimorphism for body weight is minor. In this study, at any given age, no significant differences between males and females were shown. Thus, it is possible to rear both sexes together and to slaughter them at the same age.

  13. Ab initio studies of equations of state and chemical reactions of reactive structural materials

    Science.gov (United States)

    Zaharieva, Roussislava

    The motivations for the research issues addressed in this thesis are based on the needs of the aerospace structural analysis and the design community. The specific focus is related to the characterization and shock induced chemical reactions of multi-functional structural-energetic materials that are also known as the reactive structural materials and their reaction capabilities. Usually motivation for selection of aerospace structural materials is to realize required strength characteristics and favorable strength to weight ratios. The term strength implies resistance to loads experienced during the service life of the structure, including resistance to fatigue loads, corrosion and other extreme conditions. Thus, basically the structural materials are single function materials that resist loads experienced during the service life of the structure. However, it is desirable to select materials that are capable of offering more than one basic function of strength. Very often, the second function is the capability to provide functions of sensing and actuation. In this thesis, the second function is different. The second function is the energetic characteristics. Thus, the choice of dual functions of the material are the structural characteristics and energetic characteristics. These materials are also known by other names such as the reactive material structures or dual functional structural energetic materials. Specifically the selected reactive materials include mixtures of selected metals and metal oxides that are also known as thermite mixtures, reacting intermetallic combinations and oxidizing materials. There are several techniques that are available to synthesize these structural energetic materials or reactive material structures and new synthesis techniques constitute an open research area. The focus of this thesis, however, is the characterization of chemical reactions of reactive material structures that involve two or more solids (or condensed matter). The

  14. Structural Analysis of Fungal Cerebrosides

    Directory of Open Access Journals (Sweden)

    Eliana eBarreto-Bergter

    2011-12-01

    Full Text Available Of the ceramide monohexosides (CMHs, gluco- and galactosylceramides are the main neutral glycosphingolipids expressed in fungal cells. Their structural determination is greatly dependent on the use of mass spectrometric techniques, including fast atom bombardment-mass spectrometry (FAB-MS, electrospray ionization (ESI-MS, and energy collision-induced dissociation mass spectrometry (ESI-MS/CID-MS. Nuclear magnetic resonance (NMR has also been used successfully. Such a combination of techniques, combined with classical analytical separation, such as HPTLC and column chromatography, has led to the structural elucidation of a great number of fungal CMHs. The structure of fungal CMH is conserved among fungal species and consists of a glucose or galactose residue attached to a ceramide moiety containing 9-methyl-4,8-sphingadienine with an amidic linkage to hydroxylated fatty acids, most commonly having 16 or 18 carbon atoms and unsaturation between C-3 and C-4. Along with their unique structural characteristics, fungal CMHs have a peculiar subcellular distribution and striking biological properties. Fungal cerebrosides were also characterized as antigenic molecules directly or indirectly involved in cell growth or differentiation in Schizophyllum commune, Cryptococcus neoformans, Pseudallescheria boydii, Candida albicans, Aspergillus nidulans, A.fumigatus and Colletotrichum gloeosporioides. Besides classical techniques for cerebroside (CMH analysis, we now describe new approaches, combining conventional TLC and mass spectrometry, as well as emerging technologies for subcellular localization and distribution of glycosphingolipids by SIMS and imaging MALDI TOF .

  15. Chemical etching of deformation sub-structures in quartz

    Science.gov (United States)

    Wegner, M. W.; Christie, J. M.

    1983-02-01

    Chemical etching of dislocations has been studied in natural and synthetic quartz single crystals, in deformed synthetic quartz and in naturally and experimentally deformed quartzites. The ability of different etchants to produce polished or preferentially etched surfaces on quartz is described. Dislocation etching was achieved on all crystal planes examined by using a saturated solution of ammonium bifluoride as the etchant. Appropriate etching times were determined for etching quartzites for grain size, subgrain boundaries, deformation lamellae, dislocations and twins. Growth and polished surfaces of synthetic single crystal quartz were similarly etched and dislocation etch pits, characteristic of various orientations were found. The use of ammonium bifluoride proved to be expecially advantageous for the basal plane, producing a polished surface with etch pits, suitable for dislocation etch pit counting. “Double” etch pits have been found on Dauphiné twin boundaries on the basal plane and the first order prism, using this etchant. Slip lines and deformation bands were suitably etched on deformed synthetic crystal surfaces for identification of the slip planes. Other acidic etchants have been explored and their application to the study of deformation structures in quartz crystals is discussed.

  16. Chemical Structure-Biological Activity Models for Pharmacophores' 3D-Interactions.

    Science.gov (United States)

    Putz, Mihai V; Duda-Seiman, Corina; Duda-Seiman, Daniel; Putz, Ana-Maria; Alexandrescu, Iulia; Mernea, Maria; Avram, Speranta

    2016-01-01

    Within medicinal chemistry nowadays, the so-called pharmaco-dynamics seeks for qualitative (for understanding) and quantitative (for predicting) mechanisms/models by which given chemical structure or series of congeners actively act on biological sites either by focused interaction/therapy or by diffuse/hazardous influence. To this aim, the present review exposes three of the fertile directions in approaching the biological activity by chemical structural causes: the special computing trace of the algebraic structure-activity relationship (SPECTRAL-SAR) offering the full analytical counterpart for multi-variate computational regression, the minimal topological difference (MTD) as the revived precursor for comparative molecular field analyses (CoMFA) and comparative molecular similarity indices analysis (CoMSIA); all of these methods and algorithms were presented, discussed and exemplified on relevant chemical medicinal systems as proton pump inhibitors belonging to the 4-indolyl,2-guanidinothiazole class of derivatives blocking the acid secretion from parietal cells in the stomach, the 1-[(2-hydroxyethoxy)-methyl]-6-(phenylthio)thymine congeners' (HEPT ligands) antiviral activity against Human Immunodeficiency Virus of first type (HIV-1) and new pharmacophores in treating severe genetic disorders (like depression and psychosis), respectively, all involving 3D pharmacophore interactions. PMID:27399692

  17. Chemical Structure-Biological Activity Models for Pharmacophores’ 3D-Interactions

    Directory of Open Access Journals (Sweden)

    Mihai V. Putz

    2016-07-01

    Full Text Available Within medicinal chemistry nowadays, the so-called pharmaco-dynamics seeks for qualitative (for understanding and quantitative (for predicting mechanisms/models by which given chemical structure or series of congeners actively act on biological sites either by focused interaction/therapy or by diffuse/hazardous influence. To this aim, the present review exposes three of the fertile directions in approaching the biological activity by chemical structural causes: the special computing trace of the algebraic structure-activity relationship (SPECTRAL-SAR offering the full analytical counterpart for multi-variate computational regression, the minimal topological difference (MTD as the revived precursor for comparative molecular field analyses (CoMFA and comparative molecular similarity indices analysis (CoMSIA; all of these methods and algorithms were presented, discussed and exemplified on relevant chemical medicinal systems as proton pump inhibitors belonging to the 4-indolyl,2-guanidinothiazole class of derivatives blocking the acid secretion from parietal cells in the stomach, the 1-[(2-hydroxyethoxy-methyl]-6-(phenylthiothymine congeners’ (HEPT ligands antiviral activity against Human Immunodeficiency Virus of first type (HIV-1 and new pharmacophores in treating severe genetic disorders (like depression and psychosis, respectively, all involving 3D pharmacophore interactions.

  18. Chemical Structure-Biological Activity Models for Pharmacophores’ 3D-Interactions

    Science.gov (United States)

    Putz, Mihai V.; Duda-Seiman, Corina; Duda-Seiman, Daniel; Putz, Ana-Maria; Alexandrescu, Iulia; Mernea, Maria; Avram, Speranta

    2016-01-01

    Within medicinal chemistry nowadays, the so-called pharmaco-dynamics seeks for qualitative (for understanding) and quantitative (for predicting) mechanisms/models by which given chemical structure or series of congeners actively act on biological sites either by focused interaction/therapy or by diffuse/hazardous influence. To this aim, the present review exposes three of the fertile directions in approaching the biological activity by chemical structural causes: the special computing trace of the algebraic structure-activity relationship (SPECTRAL-SAR) offering the full analytical counterpart for multi-variate computational regression, the minimal topological difference (MTD) as the revived precursor for comparative molecular field analyses (CoMFA) and comparative molecular similarity indices analysis (CoMSIA); all of these methods and algorithms were presented, discussed and exemplified on relevant chemical medicinal systems as proton pump inhibitors belonging to the 4-indolyl,2-guanidinothiazole class of derivatives blocking the acid secretion from parietal cells in the stomach, the 1-[(2-hydroxyethoxy)-methyl]-6-(phenylthio)thymine congeners’ (HEPT ligands) antiviral activity against Human Immunodeficiency Virus of first type (HIV-1) and new pharmacophores in treating severe genetic disorders (like depression and psychosis), respectively, all involving 3D pharmacophore interactions. PMID:27399692

  19. Analysis of DCC domain structure

    International Nuclear Information System (INIS)

    Wavelet-type methods are employed for the analysis of pion field configurations that have been obtained by dynamical simulations in idealized scenarios relevant to the formation of disoriented chiral condensates. It is illustrated how the measurement of the isospin domain structure depends on the ability to zoom in on limited parts of the phase space, due to the interplay between the pion correlation length and the effective source geometry. The need for advanced analysis methods is underscored by the fact that the extracted neutral-fraction distribution would differ significantly from the ideal form, even under perfect experimental conditions, and, moreover, by the circumstance that thermal sources with suitably adjusted temperatures can lead to distributions that may be practically indistinguishable from those arising from DCC-type nonequilibrium evolutions. copyright 1997 The American Physical Society

  20. Building Structural Complexity in Semiconductor Nanocrystals through Chemical Transformations

    Energy Technology Data Exchange (ETDEWEB)

    Sadtler, Bryce F

    2009-05-20

    Methods are presented for synthesizing nanocrystal heterostructures comprised of two semiconductor materials epitaxially attached within individual nanostructures. The chemical transformation of cation exchange, where the cations within the lattice of an ionic nanocrystal are replaced with a different metal ion species, is used to alter the chemical composition at specific regions ofa nanocrystal. Partial cation exchange was performed in cadmium sulfide (CdS) nanorods of well-defined size and shape to examine the spatial organization of materials within the resulting nanocrystal heterostructures. The selectivity for cation exchange to take place at different facets of the nanocrystal plays an important role in determining the resulting morphology of the binary heterostructure. The exchange of copper (I) (Cu+) cations in CdS nanorods occurs preferentially at the ends of the nanorods. Theoretical modeling of epitaxial attachments between different facets of CdS and Cu2S indicate that the selectivity for cation exchange at the ends of the nanorods is a result of the low formation energy of the interfaces produced. During silver (I) (Ag+) cation exchange in CdS nanorods, non-selective nucleation of silver sulfide (Ag2S), followed by partial phase segregation leads to significant changes in the spatial arrangement of CdS and Ag2S regions at the exchange reaction proceeds through the nanocrystal. A well-ordered striped pattern of alternating CdS and Ag2S segments is found at intermediate fractions of exchange. The forces mediating this spontaneous process are a combination of Ostwald ripening to reduce the interfacial area along with a strain-induced repulsive interaction between Ag2S segments. To elucidate why Cu+ and Ag+ cation exchange with CdS nanorods produce different morphologies, models for epitaxial attachments between various facets of CdS with Cu2S or Ag2S lattices were used to calculate interface formation energies. The formation energies indicate the

  1. Building Structural Complexity in Semiconductor Nanocrystals through Chemical Transformations

    Energy Technology Data Exchange (ETDEWEB)

    Sadtler, Bryce F [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2009-05-01

    Methods are presented for synthesizing nanocrystal heterostructures comprised of two semiconductor materials epitaxially attached within individual nanostructures. The chemical transformation of cation exchange, where the cations within the lattice of an ionic nanocrystal are replaced with a different metal ion species, is used to alter the chemical composition at specific regions ofa nanocrystal. Partial cation exchange was performed in cadmium sulfide (CdS) nanorods of well-defined size and shape to examine the spatial organization of materials within the resulting nanocrystal heterostructures. The selectivity for cation exchange to take place at different facets of the nanocrystal plays an important role in determining the resulting morphology of the binary heterostructure. The exchange of copper (I) (Cu+) cations in CdS nanorods occurs preferentially at the ends of the nanorods. Theoretical modeling of epitaxial attachments between different facets of CdS and Cu2S indicate that the selectivity for cation exchange at the ends of the nanorods is a result of the low formation energy of the interfaces produced. During silver (I) (Ag+) cation exchange in CdS nanorods, non-selective nucleation of silver sulfide (Ag2S), followed by partial phase segregation leads to significant changes in the spatial arrangement of CdS and Ag2S regions at the exchange reaction proceeds through the nanocrystal. A well-ordered striped pattern of alternating CdS and Ag2S segments is found at intermediate fractions of exchange. The forces mediating this spontaneous process are a combination of Ostwald ripening to reduce the interfacial area along with a strain-induced repulsive interaction between Ag2S segments. To elucidate why Cu+ and Ag+ cation exchange with CdS nanorods produce different morphologies, models for epitaxial attachments between various facets of CdS with Cu2S or

  2. Structural, chemical and deformation changes in friction welded joint of dissimilar steels

    Directory of Open Access Journals (Sweden)

    N. Ratković

    2014-10-01

    Full Text Available Fundamental principles of friction welding of dissimilar steels (high speed and tempering steel from the aspect of metallurgical and chemical processes occurring in the joint zone are presented in this paper. Considering that phenomena accompanying the friction welding are interdependent, it was necessary to experimentally determine the process variable parameters, to establish the optimal welding regime. The experiments were set and realized so that all the variables were analyzed as a function of the friction time. The metallographic investigations included analysis of the joint zone microstructure through structural phases and hardness changes, due to influence of the heat treatment - annealing. The experimental work included analysis of the geometry changes, the joint zone structure and the basic mechanical characteristics of the joint realized by the friction welding.

  3. Chemical analysis of Ginkgo biloba leaves and extracts

    NARCIS (Netherlands)

    Beek, van T.A.

    2002-01-01

    The chemical analysis and quality control of Ginkgo leaves and extracts is reviewed. Important constituents present in the medicinally used leaves are the terpene trilactones, i.e., ginkgolides A, B, C, J and bilobalide, many flavonol glycosides, biflavones, proanthocyanidins, alkylphenols, simple p

  4. Chemical composition and structural transformations of amorphous chromium coatings electrodeposited from Cr(III) electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Safonova, Olga V. [Swiss-Norwegian Beamlines at European Synchrotron Radiation Facility, 38043 Grenoble Cedex (France); Vykhodtseva, Ludmila N. [Department of Electrochemistry, Faculty of Chemistry, Moscow State University, 119991 Moscow (Russian Federation); Polyakov, Nikolai A. [A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 119991 Moscow (Russian Federation); Swarbrick, Janine C. [European Synchrotron Radiation Facility, 38043 Grenoble Cedex (France); Sikora, Marcin [European Synchrotron Radiation Facility, 38043 Grenoble Cedex (France); Department of Solid State Physics, Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Av. Mickiewicza 30, 30-059 Krakow (Poland); Glatzel, Pieter [European Synchrotron Radiation Facility, 38043 Grenoble Cedex (France); Safonov, Viktor A., E-mail: safon@elch.chem.msu.r [Department of Electrochemistry, Faculty of Chemistry, Moscow State University, 119991 Moscow (Russian Federation)

    2010-12-15

    Amorphous chromium coatings were electrodeposited from Cr(III)-based solutions containing organic (HCOONa) or phosphorus-containing (NaH{sub 2}PO{sub 2}) additives. Their structure was studied by a combination of X-ray diffraction (XRD), valence-to-core X-ray emission spectroscopy (XES) and X-ray absorption spectroscopy (XAS) at the Cr K-edge. Metalloid atoms (C or P) incorporated in electroplates structure are chemically bonded to chromium (i.e. are located in the first coordination shell). Upon annealing at elevated temperatures in vacuum, these amorphous coatings crystallize into a mixture of phases containing metallic chromium and chromium carbides or chromium phosphides. Quantitative analysis of valence-to-core XES data demonstrates that the average local structure of chromium in the amorphous coatings does not change significantly during crystallization.

  5. YNi and its hydrides: Phase stabilities, electronic structures and chemical bonding properties from first principles

    Energy Technology Data Exchange (ETDEWEB)

    Matar, S.F., E-mail: matar@icmcb-bordeaux.cnrs.fr [CNRS, Universite de Bordeaux, ICMCB, 87 avenue du Docteur Albert Schweitzer, F-33608 Pessac (France); Nakhl, M. [Universite Libanaise, Laboratoire de Chimie-Physique des Materiaux LCPM, Fanar (Lebanon); Al Alam, A.F.; Ouaini, N. [Universite Saint-Esprit de Kaslik, Faculte des Sciences et de Genie Informatique, Jounieh (Lebanon); Chevalier, B. [CNRS, Universite de Bordeaux, ICMCB, 87 avenue du Docteur Albert Schweitzer, F-33608 Pessac (France)

    2010-11-25

    Graphical abstract: Base centered orthorhombic YNiH{sub X} structure. For x = 3, only H1 and H2 are present. Highest hydrogen content YNiH{sub 4} is obtained when H3 are added. - Abstract: Within density functional theory, establishing the equations of states of YNi in two different controversial structures in the literature, leads to determine the orthorhombic FeB-type as the ground state one with small energy difference. For YNiH{sub 3} and YNiH{sub 4} hydrides crystallizing in the orthorhombic CrB-type structure the geometry optimization and the ab initio determination of the H atomic positions show that the stability of hydrogen decreases from the tri- to the tetra- hydride. New states brought by hydrogen within the valence band lead to its broadening and to enhanced localization of metal density of states. The chemical bonding analysis shows a preferential Ni-H bonding versus Y-H.

  6. Shotgun lipidomic analysis of chemically sulfated sterols compromises analytical sensitivity

    DEFF Research Database (Denmark)

    Casanovas, Albert; Hannibal-Bach, Hans Kristian; Jensen, Ole Nørregaard;

    2014-01-01

    Fourier transform mass spectrometry (FTMS) for identification and quantification of lipid species [6]. Shotgun lipidomics affords extensive lipidome coverage by combining the analysis of lipid extracts in positive and negative ion mode [1, 3]. Notably, sterols such as cholesterol and ergosterol exhibit...... low ionization efficiency in ESI [7]. For this reason, chemical derivatization procedures including acetylation [8] or sulfation [9] are commonly implemented to facilitate ionization, detection and quantification of sterols for global lipidome analysis [1-3, 10]....

  7. Surface characterization and chemical analysis of bamboo substrates pretreated by alkali hydrogen peroxide.

    Science.gov (United States)

    Song, Xueping; Jiang, Yan; Rong, Xianjian; Wei, Wei; Wang, Shuangfei; Nie, Shuangxi

    2016-09-01

    The surface characterization and chemical analysis of bamboo substrates by alkali hydrogen peroxide pretreatment (AHPP) were investigated in this study. The results tended to manifest that AHPP prior to enzymatic and chemical treatment was potential for improving accessibility and reactivity of bamboo substrates. The inorganic components, organic solvent extractives and acid-soluble lignin were effectively removed by AHPP. X-ray photoelectron spectroscopy (XPS) analysis indicated that the surface of bamboo chips had less lignin but more carbohydrate after pre-treatment. Fiber surfaces became etched and collapsed, and more pores and debris on the substrate surface were observed with Scanning Electron Microscopy (SEM). Brenauer-Emmett-Teller (BET) results showed that both of pore volume and surface area were increased after AHPP. Although XRD analysis showed that AHPP led to relatively higher crystallinity, pre-extraction could overall enhance the accessibility of enzymes and chemicals into the bamboo structure. PMID:27311789

  8. Optimization of chemical structure of Schottky-type selection diode for crossbar resistive memory.

    Science.gov (United States)

    Kim, Gun Hwan; Lee, Jong Ho; Jeon, Woojin; Song, Seul Ji; Seok, Jun Yeong; Yoon, Jung Ho; Yoon, Kyung Jean; Park, Tae Joo; Hwang, Cheol Seong

    2012-10-24

    The electrical performances of Pt/TiO(2)/Ti/Pt stacked Schottky-type diode (SD) was systematically examined, and this performance is dependent on the chemical structures of the each layer and their interfaces. The Ti layers containing a tolerable amount of oxygen showed metallic electrical conduction characteristics, which was confirmed by sheet resistance measurement with elevating the temperature, transmission line measurement (TLM), and Auger electron spectroscopy (AES) analysis. However, the chemical structure of SD stack and resulting electrical properties were crucially affected by the dissolved oxygen concentration in the Ti layers. The lower oxidation potential of the Ti layer with initially higher oxygen concentration suppressed the oxygen deficiency of the overlying TiO(2) layer induced by consumption of the oxygen from TiO(2) layer. This structure results in the lower reverse current of SDs without significant degradation of forward-state current. Conductive atomic force microscopy (CAFM) analysis showed the current conduction through the local conduction paths in the presented SDs, which guarantees a sufficient forward-current density as a selection device for highly integrated crossbar array resistive memory. PMID:22999222

  9. Optimization of chemical structure of Schottky-type selection diode for crossbar resistive memory.

    Science.gov (United States)

    Kim, Gun Hwan; Lee, Jong Ho; Jeon, Woojin; Song, Seul Ji; Seok, Jun Yeong; Yoon, Jung Ho; Yoon, Kyung Jean; Park, Tae Joo; Hwang, Cheol Seong

    2012-10-24

    The electrical performances of Pt/TiO(2)/Ti/Pt stacked Schottky-type diode (SD) was systematically examined, and this performance is dependent on the chemical structures of the each layer and their interfaces. The Ti layers containing a tolerable amount of oxygen showed metallic electrical conduction characteristics, which was confirmed by sheet resistance measurement with elevating the temperature, transmission line measurement (TLM), and Auger electron spectroscopy (AES) analysis. However, the chemical structure of SD stack and resulting electrical properties were crucially affected by the dissolved oxygen concentration in the Ti layers. The lower oxidation potential of the Ti layer with initially higher oxygen concentration suppressed the oxygen deficiency of the overlying TiO(2) layer induced by consumption of the oxygen from TiO(2) layer. This structure results in the lower reverse current of SDs without significant degradation of forward-state current. Conductive atomic force microscopy (CAFM) analysis showed the current conduction through the local conduction paths in the presented SDs, which guarantees a sufficient forward-current density as a selection device for highly integrated crossbar array resistive memory.

  10. Structural, optical and electrical properties of chemically deposited copper selenide films

    Indian Academy of Sciences (India)

    R H Bari; V Ganesan; S Potadar; L A Patil

    2009-02-01

    Stoichiometric and nonstoichiometric thin films of copper selenide have been prepared by chemical bath deposition technique at temperature below 60°C on glass substrate. The effect of nonstoichiometry on the optical, electrical and structural properties of the film was studied. The bandgap energy was observed to increase with the increase in at % of copper in composition. The grain size was also observed to increase with the decrease of at % of copper in composition. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS), absorption spectroscopy, and AFM. The results are discussed and interpreted.

  11. Coordination compounds of tetravalent silicon, germanium and tin: the structure, chemical bonding and intermolecular interactions in them

    Science.gov (United States)

    Korlyukov, A. A.

    2015-04-01

    The review is devoted to analysis and generalization of the results of (i) quantum chemical studies on the structure, chemical bonding and intermolecular interactions in coordination compounds of tetravalent silicon, germanium and tin in crystals, in solutions and in the gas phase and (ii) experimental investigations of the electron density distribution in these systems. The bibliography includes 147 references. In memoriam of Corresponding Member of the Russian Academy of Sciences M Yu Antipin (1951 - 2013), Academician of the Russian Academy of Sciences M G Voronkov (1921 - 2014) and Dr. S P Knyazev, Lomonosov Moscow University of Fine Chemical Technology (1949 - 2012).

  12. Aged nano-structured platinum based catalyst: effect of chemical treatment on adsorption and catalytic activity.

    Science.gov (United States)

    Shim, Wang Geun; Nahm, Seung Won; Park, Hyuk Ryeol; Yun, Hyung Sun; Seo, Seong Gyu; Kim, Sang Chai

    2011-02-01

    To examine the effect of chemical treatment on the adsorption and catalytic activity of nanostructured platinum based catalyst, the aged commercial Pt/AC catalyst was pretreated with sulfuric acid (H2SO4) and a cleaning agent (Hexane). Several reliable methods such as nitrogen adsorption, X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and inductively coupled plasma (ICP) were employed to characterize the aged Pt/AC catalyst and its chemically pretreated Pt/AC catalysts. The catalytic and adsorption activities of nano-structured heterogeneous Pt/AC catalyst were investigated on the basis of toluene oxidation and adsorption isotherm data. In addition, the adsorption isotherms of toluene were used to calculate the adsorption energy distribution functions for the parent catalyst and its pre-treated nano-structured Pt/AC catalysts. It was found that sulfuric acid aqueous treatment can enhance the catalytic performance of aged Pt/AC catalyst toward catalytic oxidation of toluene. It was also shown that a comparative analysis of the energy distribution functions for nano-structured Pt/AC catalysts as well as the pore size distribution provides valuable information about their structural and energetic heterogeneity.

  13. Chemical and physical analysis of core materials for advanced high temperature reactors with process heat applications

    International Nuclear Information System (INIS)

    Various chemical and physical methods for the analysis of structural materials have been developed in the research programmes for advanced high temperature reactors. These methods are discussed using as examples the structural materials of the reactor core - the fuel elements consisting of coated particles in a graphite matrix and the structural graphite. Emphasis is given to the methods of chemical analysis. The composition of fuel kernels is investigated using chemical analysis methods to determine the heavy metals content (uranium, plutonium, thorium and metallic impurity elements) and the amount of non-metallic constituents. The properties of the pyrocarbon and silicon carbide coatings of fuel elements are investigated using specially developed physiochemical methods. Regarding the irradiation behaviour of coated particles and fuel elements, methods have been developed for examining specimens in hot cells following exposures under reactor operating conditions, to supplement the measurements of in-reactor performance. For the structural graphite, the determination of impurities is important because certain impurities may cause pitting corrosion during irradiation. The localized analysis of very low impurity concentrations is carried out using spectrochemical d.c. arc excitation, local laser and inductively coupled plasma methods. (orig.)

  14. An Extended Algorithm of Flexibility Analysis in Chemical Engineering Processes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An extended algorithm of flexibility analysis with a local adjusting method for flexibility region of chemical processes, which is based on the active constraint strategy, is proposed, which fully exploits the flexibility region of the process system operation. The hyperrectangular flexibility region determined by the extended algorithm is larger than that calculated by the previous algorithms. The limitation of the proposed algorithm due to imperfect convexity and its corresponding verification measure are also discussed. Both numerical and actual chemical process examples are presented to demonstrate the effectiveness of the new algorithm.

  15. The Impact of Flow Injection on Modern Chemical Analysis

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    There is no doubt that Flow Injection Analysis (FIA) has had a profound impact on the ways and means that modern analytical chemical procedures are performed. This is amply reflected in the voluminous scientific literature, which by the middle of 2004 passed more than 14,500 FIA-publications in i......There is no doubt that Flow Injection Analysis (FIA) has had a profound impact on the ways and means that modern analytical chemical procedures are performed. This is amply reflected in the voluminous scientific literature, which by the middle of 2004 passed more than 14,500 FIA...... and preconcentration procedures. In recent years, FIA has been supplemented by Sequential Injection Analysis (SIA) and the Lab-on-Valve (LOV) approach. Following a brief historic introduction and an account of the impact of FIA in academia, the lecture will describe these two new generations of FIA, accompanied...

  16. Quantitative Survey and Structural Classification of Hydraulic Fracturing Chemicals Reported in Unconventional Gas Production.

    Science.gov (United States)

    Elsner, Martin; Hoelzer, Kathrin

    2016-04-01

    Much interest is directed at the chemical structure of hydraulic fracturing (HF) additives in unconventional gas exploitation. To bridge the gap between existing alphabetical disclosures by function/CAS number and emerging scientific contributions on fate and toxicity, we review the structural properties which motivate HF applications, and which determine environmental fate and toxicity. Our quantitative overview relied on voluntary U.S. disclosures evaluated from the FracFocus registry by different sources and on a House of Representatives ("Waxman") list. Out of over 1000 reported substances, classification by chemistry yielded succinct subsets able to illustrate the rationale of their use, and physicochemical properties relevant for environmental fate, toxicity and chemical analysis. While many substances were nontoxic, frequent disclosures also included notorious groundwater contaminants like petroleum hydrocarbons (solvents), precursors of endocrine disruptors like nonylphenols (nonemulsifiers), toxic propargyl alcohol (corrosion inhibitor), tetramethylammonium (clay stabilizer), biocides or strong oxidants. Application of highly oxidizing chemicals, together with occasional disclosures of putative delayed acids and complexing agents (i.e., compounds designed to react in the subsurface) suggests that relevant transformation products may be formed. To adequately investigate such reactions, available information is not sufficient, but instead a full disclosure of HF additives is necessary. PMID:26902161

  17. Temporal evolution of the chemical structure during the pattern transfer by ion-beam sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Ha, N.-B.; Jeong, S.; Yu, S.; Ihm, H.-I.; Kim, J.-S.

    2015-01-01

    Highlights: • Chemical analyses of the individual nano structures simultaneously with the investigation of their morphological evolution were performed. • Degradation of the transferred pattern starts before the overlayer is fully removed. • The chemical analysis reveals the severe reduction of the sputter yield of the material forming the overlayer near the interface due to the compound formation, requesting caution in the practice of the pattern transfer. - Abstract: Ru films patterned by ion-beam sputtering (IBS) serve as sacrificial masks for the transfer of the patterns to Si(1 0 0) and metallic glass substrates by continued IBS. Under the same sputter condition, however, both bare substrates remain featureless. Chemical analyses of the individual nano structures simultaneously with the investigation of their morphological evolution reveal that the pattern transfer, despite its apparent success, suffers from premature degradation before the mask is fully removed by IBS. Moreover, the residue of the mask or Ru atoms stubbornly remains near the surface, resulting in unintended doping or alloying of both patterned substrates.

  18. Chemical, physical, structural and morphological characterization of the electric arc furnace dust.

    Science.gov (United States)

    Machado, Janaína G M S; Brehm, Feliciane Andrade; Moraes, Carlos Alberto Mendes; Santos, Carlos Alberto Dos; Vilela, Antônio Cezar Faria; Cunha, João Batista Marimon da

    2006-08-25

    Electric arc furnace dust (EAFD) is a hazardous industrial waste generated in the collection of particulate material during steelmaking process via electric arc furnace. Important elements to the industry such as, Fe and Zn are the main ones in EAFD. Due to their presence, it becomes very important to know how these elements are combined before studying new technologies for its processing. The aim of this work was to carry out a chemical, physical, structural and morphological characterization of the EAFD. The investigation was carried out by using granulometry analysis, chemical analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy via SEM (EDS), X-ray mapping analysis via SEM, X-ray diffraction (XRD) and Mössbauer spectroscopy. By XRD the following phases were detected: ZnFe(2)O(4), Fe(3)O(4), MgFe(2)O(4), FeCr(2)O (4), Ca(0.15)Fe(2.85)O(4), MgO, Mn(3)O(4), SiO(2) and ZnO. On the other hand, the phases detected by Mössbauer spectroscopy were: ZnFe(2)O(4), Fe(3)O(4), Ca(0.15)Fe(2.85)O(4) and FeCr(2)O(4). Magnesium ferrite (MgFe(2)O(4)), observed in the XRD pattern as overlapped peaks, was not identified in the Mössbauer spectroscopy analysis.

  19. Spectroscopic and quantum chemical analysis of Isonicotinic acid methyl ester

    Science.gov (United States)

    Shoba, D.; Periandy, S.; Govindarajan, M.; Gayathri, P.

    2015-02-01

    In this present study, an organic compound Isonicotinic acid methyl ester (INAME) was structurally characterized by FTIR, FT-Raman, and NMR and UV spectroscopy. The optimized geometrical parameters and energies of all different and possible conformers of INAME are obtained from Density Functional Theory (DFT) by B3LYP/6-311++G(d,p) method. There are three conformers (SI, SII-1, and SII-2) for this molecule (ground state). The most stable conformer of INAME is SI conformer. The molecular geometry and vibrational frequencies of INAME in the ground state have been calculated by using HF and density functional method (B3LYP) 6-311++G (d,p) basis set. Detailed vibrational spectral analysis has been carried out and assignments of the observed fundamental bands have been proposed on the basis of peak positions and relative intensities. The computed vibrational frequencies were compared with the experimental frequencies, which yield good agreement between observed and calculated frequencies. A study on the electronic properties, such as HOMO and LUMO energies were performed by time independent DFT approach. Besides, molecular electrostatic potential (MEP) and thermodynamic properties were performed. The electric dipole moment (μ) and first hyper polarizability (β) values of the investigated molecule were computed using ab initio quantum mechanical calculations. The calculated results show that the INAME molecule may have microscopic nonlinear optical (NLO) behavior with non zero values. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by gauge independent atomic orbital (GIAO) method.

  20. Applications of Mass Spectrometry to Structural Analysis of Marine Oligosaccharides

    Directory of Open Access Journals (Sweden)

    Yinzhi Lang

    2014-06-01

    Full Text Available Marine oligosaccharides have attracted increasing attention recently in developing potential drugs and biomaterials for their particular physical and chemical properties. However, the composition and sequence analysis of marine oligosaccharides are very challenging for their structural complexity and heterogeneity. Mass spectrometry (MS has become an important technique for carbohydrate analysis by providing more detailed structural information, including molecular mass, sugar constituent, sequence, inter-residue linkage position and substitution pattern. This paper provides an overview of the structural analysis based on MS approaches in marine oligosaccharides, which are derived from some biologically important marine polysaccharides, including agaran, carrageenan, alginate, sulfated fucan, chitosan, glycosaminoglycan (GAG and GAG-like polysaccharides. Applications of electrospray ionization mass spectrometry (ESI-MS are mainly presented and the general applications of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS are also outlined. Some technical challenges in the structural analysis of marine oligosaccharides by MS have also been pointed out.

  1. Risk Analysis of Marine Structures

    DEFF Research Database (Denmark)

    Hansen, Peter Friis

    1998-01-01

    Basic concepts of risk analysis is introduced. Formulation and analysis of fault and event trees are treated.......Basic concepts of risk analysis is introduced. Formulation and analysis of fault and event trees are treated....

  2. Automated Structure-Activity Relationship Mining: Connecting Chemical Structure to Biological Profiles.

    Science.gov (United States)

    Wawer, Mathias J; Jaramillo, David E; Dančík, Vlado; Fass, Daniel M; Haggarty, Stephen J; Shamji, Alykhan F; Wagner, Bridget K; Schreiber, Stuart L; Clemons, Paul A

    2014-06-01

    Understanding the structure-activity relationships (SARs) of small molecules is important for developing probes and novel therapeutic agents in chemical biology and drug discovery. Increasingly, multiplexed small-molecule profiling assays allow simultaneous measurement of many biological response parameters for the same compound (e.g., expression levels for many genes or binding constants against many proteins). Although such methods promise to capture SARs with high granularity, few computational methods are available to support SAR analyses of high-dimensional compound activity profiles. Many of these methods are not generally applicable or reduce the activity space to scalar summary statistics before establishing SARs. In this article, we present a versatile computational method that automatically extracts interpretable SAR rules from high-dimensional profiling data. The rules connect chemical structural features of compounds to patterns in their biological activity profiles. We applied our method to data from novel cell-based gene-expression and imaging assays collected on more than 30,000 small molecules. Based on the rules identified for this data set, we prioritized groups of compounds for further study, including a novel set of putative histone deacetylase inhibitors.

  3. Chemical analysis of thin films at Sandia National Laboratories

    International Nuclear Information System (INIS)

    The characterization of thin films produced by chemical and physical vapor deposition requires special analytical techniques. When the average compositions of the films are required, dissolution of the thin films and measurement of the concentrations of the solubilized species is the appropriate analytical approach. In this report techniques for the wet chemical analysis of thin films of Si:Al, P2O5:SiO2, B2O3:SiO2, TiB/sub x/ and TaB/sub x/ are described. The analyses are complicated by the small total quantities of these analytes present in the films, the refractory characters of these analytes, and the possibility of interferences from the substrates on which the films are deposited. Etching conditions are described which dissolve the thin films without introducing interferences from the substrates. A chemical amplification technique and inductively coupled plasma atomic emission spectrometry are shown to provide the sensitivity required to measure the small total quantities (micrograms to milligrams) of analytes present. Also the chemical analysis data has been used to calibrate normal infrared absorption spectroscopy to give fast estimates of the phosphorus and/or boron dopant levels in thin SiO2 films

  4. Chemical crosslinking and mass spectrometry studies of the structure and dynamics of membrane proteins and receptors.

    Energy Technology Data Exchange (ETDEWEB)

    Haskins, William E.; Leavell, Michael D.; Lane, Pamela; Jacobsen, Richard B.; Hong, Joohee; Ayson, Marites J.; Wood, Nichole L.; Schoeniger, Joseph S.; Kruppa, Gary Hermann; Sale, Kenneth L.; Young, Malin M.; Novak, Petr

    2005-03-01

    Membrane proteins make up a diverse and important subset of proteins for which structural information is limited. In this study, chemical cross-linking and mass spectrometry were used to explore the structure of the G-protein-coupled photoreceptor bovine rhodopsin in the dark-state conformation. All experiments were performed in rod outer segment membranes using amino acid 'handles' in the native protein sequence and thus minimizing perturbations to the native protein structure. Cysteine and lysine residues were covalently cross-linked using commercially available reagents with a range of linker arm lengths. Following chemical digestion of cross-linked protein, cross-linked peptides were identified by accurate mass measurement using liquid chromatography-fourier transform mass spectrometry and an automated data analysis pipeline. Assignments were confirmed and, if necessary, resolved, by tandem MS. The relative reactivity of lysine residues participating in cross-links was evaluated by labeling with NHS-esters. A distinct pattern of cross-link formation within the C-terminal domain, and between loop I and the C-terminal domain, emerged. Theoretical distances based on cross-linking were compared to inter-atomic distances determined from the energy-minimized X-ray crystal structure and Monte Carlo conformational search procedures. In general, the observed cross-links can be explained by re-positioning participating side-chains without significantly altering backbone structure. One exception, between C3 16 and K325, requires backbone motion to bring the reactive atoms into sufficient proximity for cross-linking. Evidence from other studies suggests that residues around K325 for a region of high backbone mobility. These findings show that cross-linking studies can provide insight into the structural dynamics of membrane proteins in their native environment.

  5. Selectivity on-target of bromodomain chemical probes by structure-guided medicinal chemistry and chemical biology.

    Science.gov (United States)

    Galdeano, Carles; Ciulli, Alessio

    2016-09-01

    Targeting epigenetic proteins is a rapidly growing area for medicinal chemistry and drug discovery. Recent years have seen an explosion of interest in developing small molecules binding to bromodomains, the readers of acetyl-lysine modifications. A plethora of co-crystal structures has motivated focused fragment-based design and optimization programs within both industry and academia. These efforts have yielded several compounds entering the clinic, and many more are increasingly being used as chemical probes to interrogate bromodomain biology. High selectivity of chemical probes is necessary to ensure biological activity is due to an on-target effect. Here, we review the state-of-the-art of bromodomain-targeting compounds, focusing on the structural basis for their on-target selectivity or lack thereof. We also highlight chemical biology approaches to enhance on-target selectivity.

  6. Control of interface nanoscale structure created by plasma-enhanced chemical vapor deposition.

    Science.gov (United States)

    Peri, Someswara R; Akgun, Bulent; Satija, Sushil K; Jiang, Hao; Enlow, Jesse; Bunning, Timothy J; Foster, Mark D

    2011-09-01

    Tailoring the structure of films deposited by plasma-enhanced chemical vapor deposition (PECVD) to specific applications requires a depth-resolved understanding of how the interface structures in such films are impacted by variations in deposition parameters such as feed position and plasma power. Analysis of complementary X-ray and neutron reflectivity (XR, NR) data provide a rich picture of changes in structure with feed position and plasma power, with those changes resolved on the nanoscale. For plasma-polymerized octafluorocyclobutane (PP-OFCB) films, a region of distinct chemical composition and lower cross-link density is found at the substrate interface for the range of processing conditions studied and a surface layer of lower cross-link density also appears when plasma power exceeds 40 W. Varying the distance of the feed from the plasma impacts the degree of cross-linking in the film center, thickness of the surface layer, and thickness of the transition region at the substrate. Deposition at the highest power, 65 W, both enhances cross-linking and creates loose fragments with fluorine content higher than the average. The thickness of the low cross-link density region at the air interface plays an important role in determining the width of the interface built with a layer subsequently deposited atop the first.

  7. Robustness Analysis of Kinetic Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2009-01-01

    The present paper considers robustness of kinetic structures. Robustness of structures has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. Especially for these types of structural syst...

  8. Cluster analysis to evaluate stable chemical elements and physical-chemical parameters behavior on uranium mining waste

    International Nuclear Information System (INIS)

    The Ore Treating Unit (UTM, in portuguese) is a deactivated uranium mine. A cluster analysis was used to evaluate the behavior of stable chemical elements and physical-chemical parameters in their effluents. The utilization of the cluster analysis proved itself effective in the assessment, allowing the identification of groups of chemical elements, physical-chemical parameters and their joint analysis (elements and parameters). As a result we may assert, based on data analysis, that there is a strong link between calcium and magnesium and between aluminum and rare-earth oxides on UTM's effluents. Sulphate was also identified as strongly linked to total and dissolved solids, and those to electrical conductivity. There were other associations, but not so strongly linked. Further gathering, to seasonal evaluation, are required in order to confirm those analysis. Additional statistical analysis (factor analysis) must be used to try to identify the origin of the identified groups on this analysis. (author)

  9. Device for high spatial resolution chemical analysis of a sample and method of high spatial resolution chemical analysis

    Science.gov (United States)

    Van Berkel, Gary J.

    2015-10-06

    A system and method for analyzing a chemical composition of a specimen are described. The system can include at least one pin; a sampling device configured to contact a liquid with a specimen on the at least one pin to form a testing solution; and a stepper mechanism configured to move the at least one pin and the sampling device relative to one another. The system can also include an analytical instrument for determining a chemical composition of the specimen from the testing solution. In particular, the systems and methods described herein enable chemical analysis of specimens, such as tissue, to be evaluated in a manner that the spatial-resolution is limited by the size of the pins used to obtain tissue samples, not the size of the sampling device used to solubilize the samples coupled to the pins.

  10. Raman imaging to study structural and chemical features of the dentin enamel junction

    Science.gov (United States)

    Alebrahim, M. Anwar; Krafft, C.; Popp, J.

    2015-10-01

    The structure and chemical features of the human dentin enamel junction (DEJ) were characterized using Raman spectroscopic imaging. Slices were prepared from 10 German, and 10 Turkish teeth. Raman images were collected at 785 nm excitation and the average Raman spectra were calculated for analysis. Univariate and multivariate spectral analysis were applied for investigation. Raman images were obtained based on the intensity ratios of CH at 1450 cm-1 (matrix) to phosphate at 960 cm-1 (mineral), and carbonate to phosphate (1070/960) ratios. Different algorithms (HCA, K-means cluster and VCA) also used to study the DEJ. The obtained results showed that the width of DEJ is about 5 pm related to univariate method while it varies from 6 to 12 μm based on multivariate spectral technique. Both spectral analyses showed increasing in carbonate content inside the DEJ compared to the dentin, and the amide I (collagen) peak in dentin spectra is higher than DEJ spectra peak.

  11. Electrochemical approaches for chemical and biological analysis on Mars

    Science.gov (United States)

    Kounaves, Samuel P.

    2003-01-01

    Obtaining in situ chemical data from planetary bodies such as Mars or Europa can present significant challenges. The one analytical technique that has many of the requisite characteristics to meet such a challenge is electroanalysis. Described here are three electroanalytical devices designed for in situ geochemical and biological analysis on Mars. The Mars Environmental Compatibility Assessment (MECA) was built and flight qualified for the now cancelled NASA Mars 2001 Lander. Part of MECA consisted of four "cells" containing arrays of electrochemical based sensors for measuring the ionic species in soil samples. A next-generation MECA, the Robotic Chemical Analysis Laboratory (RCAL), uses a carousel-type system to allow for greater customization of analytical procedures. A second instrument, proposed as part of the 2007 CryoScout mission, consists of a flow-through inorganic chemical analyzer (MICA). CryoScout is a torpedo-like device designed for subsurface investigation of the stratigraphic climate record embedded in Mars' north polar cap. As the CryoScout melts its way through the ice cap, MICA will collect and analyze the meltwater for a variety of inorganics and chemical parameters. By analyzing the chemistry locked in the layers of dust, salt, and ice, geologists will be able to determine the recent history of climate, water, and atmosphere on Mars and link it to the past. Finally, electroanalysis shows its abilities in the detection of possible microorganism on Mars or elsewhere in the solar system. To identify an unknown microorganism, one that may not even use Earth-type biochemistry, requires a detection scheme which makes minimal assumptions and looks for the most general features. Recent work has demonstrated that the use of an array of electrochemical sensors which monitors the changes in a solution via electrical conductivity, pH, and ion selective electrodes, can be used to detect minute chemical perturbations caused by the growth of bacteria and

  12. Structure and biological activity of chemically modified nisin A species

    NARCIS (Netherlands)

    Rollema, Harry S.; Metzger, Jörg W.; Both, Paula; Kuipers, Oscar P.; Siezen, Roland J.

    1996-01-01

    Nisin, a 34-residue peptide bacteriocin, contains the less common amino acids lanthionine, β-methyllanthionine, dehydroalanine (Dha), and dehydrobutyrine (Dhb). Several chemically modified nisin A species were purified by reverse-phase HPLC and characterized by two-dimensional NMR and electrospray m

  13. Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

    OpenAIRE

    Lee, H. V.; S. B. A. Hamid; Zain, S. K.

    2014-01-01

    Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate’s application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulo...

  14. Observations on the morphology and chemical analysis of medullary granules in chinchilla hair. Research letters

    Energy Technology Data Exchange (ETDEWEB)

    Keogh, H.J. (South African Inst. for Medical Research, Johannesburg); Haylett, T. (Council for Scientific and Industrial Research, Pretoria (South Africa). National Chemical Research Lab.)

    1983-02-01

    The ultrastructure of the medullary granules of white and grey chinchilla hair was investigated by scanning electron microscopy and chemical analysis in an attempt to clarify their structure and function. Atomic absorption spectroscopy and amino acid analysis showed them to be composed of melanin. The sample preparation for scanning electron microscopy is discussed. The metal content was qualitatively established by X-ray fluorescence spectrometry and quantitatively determined on a Varian Techtron model AAs atomic absorption spectrophotometer. Amino acid analysis of the granule, was carried out on a Beckman 121 amino acid analyser. Information is provided on the amino acid composition of the medullary granules as well as its metal content.

  15. Observations on the morphology and chemical analysis of medullary granules in chinchilla hair

    International Nuclear Information System (INIS)

    The ultrastructure of the medullary granules of white and grey chinchilla hair was investigated by scanning electron microscopy and chemical analysis in an attempt to clarify their structure and function. Atomic absorption spectroscopy and amino acid analysis showed them to be composed of melanin. The sample preparation for scanning electron microscopy is discussed. The metal content was qualitatively established by X-ray fluorescence spectrometry and quantitatively determined on a Varian Techtron model AAs atomic absorption spectrophotometer. Amino acid analysis of the granule, was carried out on a Beckman 121 amino acid analyser. Information is provided on the amino acid composition of the medullary granules as well as its metal content

  16. Application of physico-chemical procedures in the analysis of urinary calculi

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, A.L.

    1985-01-01

    All physico-chemical techniques used in the analysis of urinary calculi have inherent advantages and limitations. Although x-ray powder diffraction can identify constituents unambiguously, certain minor components can be missed. Infrared spectroscopy is more sensitive but band assignment at low concentrations is difficult. Scanning electron microscopy together with energy dispersive x-ray analysis permits the simultaneous investigation of morphology and chemical microstructure. With the electron microprobe, minor constituents can be detected but tedious sample preparation procedures are required. Transmission electron microscopy is extremely useful in determining constituent inter-relationships and ultrastructure but ultramicrotomy is very difficult. Thermal gravimetric analysis gives quantitative information easily but does not satisfactorily distinguish between struvite and brushite. In an attempt to assess the accuracy of chemical analyses, 62 calculi were investigated applying several chemical tests. Those for MgS , PO4(T ), NHU and uric acid proved highly reliable while that for CaS often yielded an incorrect result. The test for oxalate was totally unsatisfactory. Investigators of stone composition and structure should include x-ray diffraction (or infrared spectroscopy) and scanning electron microscopy as their methods of first choice. In addition, chemical or thermogravimetric analyses should be utilized in an auxiliary capacity.

  17. The designability of protein switches by chemical rescue of structure: mechanisms of inactivation and reactivation

    Science.gov (United States)

    Xia, Yan; DiPrimio, Nina; Keppel, Theodore R.; Vo, Binh; Fraser, Keith; Battaile, Kevin P.; Egan, Chet; Bystroff, Christopher; Lovell, Scott; Weis, David D.; Anderson, J. Christopher; Karanicolas, John

    2014-01-01

    The ability to selectively activate function of particular proteins via pharmacological agents is a longstanding goal in chemical biology. Recently, we reported an approach for designing a de novo allosteric effector site directly into the catalytic domain of an enzyme. This approach is distinct from traditional chemical rescue of enzymes in that it relies on disruption and restoration of structure, rather than active site chemistry, as a means to achieve modulate function. However, rationally identifying analogous de novo binding sites in other enzymes represents a key challenge for extending this approach to introduce allosteric control into other enzymes. Here we show that mutation sites leading to protein inactivation via tryptophan-to-glycine substitution and allowing (partial) reactivation by the subsequent addition of indole are remarkably frequent. Through a suite of methods including a cell-based reporter assay, computational structure prediction and energetic analysis, fluorescence studies, enzymology, pulse proteolysis, x-ray crystallography and hydrogen-deuterium mass spectrometry we find that these switchable proteins are most commonly modulated indirectly, through control of protein stability. Addition of indole in these cases rescues activity not by reverting a discrete conformational change, as we had observed in the sole previously reported example, but rather rescues activity by restoring protein stability. This important finding will dramatically impact the design of future switches and sensors built by this approach, since evaluating stability differences associated with cavity-forming mutations is a far more tractable task than predicting allosteric conformational changes. By analogy to natural signaling systems, the insights from this study further raise the exciting prospect of modulating stability to design optimal recognition properties into future de novo switches and sensors built through chemical rescue of structure. PMID:24313858

  18. Kinematic Analysis of Tensegrity Structures

    OpenAIRE

    Whittier, William Brooks

    2002-01-01

    Tensegrity structures consist of isolated compression members (rigid bars) suspended by a continuous network of tension members (cables). Tensegrity structures can be used as variable geometry truss (VGT) mechanisms by actuating links to change their length. This paper will present a new method of position finding for tensegrity structures that can be used for actuation as VGT mechanisms. Tensegrity structures are difficult to understand and mathematically model. This difficulty is p...

  19. Branch Structure of Corona Discharge:Experimental Simulation and Chemical Properties

    Institute of Scientific and Technical Information of China (English)

    邹吉军; 刘昌俊

    2004-01-01

    The branch structure of corona discharge has been investigated via C2H2 corona discharge. Carbon filament with excellent branch structure is formed in the discharge. This carbon filament offers a direct mimic of the branch structure of corona discharge. It providesa very useful way to study on the average energy, physical and chemical characteristics of coronadischarge. On this basis, the chemical property of corona discharge for methane conversion is discussed.

  20. Structural Analysis of Steel Structures under Fire Loading

    Directory of Open Access Journals (Sweden)

    C. Crosti

    2009-01-01

    Full Text Available This paper focuses on the structural analysis of a steel structure under fire loading. In this framework, the objective is to highlight the importance of the right choice of analyses to develop, and of the finite element codes able to model the resistance and stiffness reduction due to the temperature increase. In addition, the evaluation of the structural collapse under fire load of a real building is considered, paying attention to the global behavior of the structure itself. 

  1. Structure activity studies of an analgesic drug tapentadol hydrochloride by spectroscopic and quantum chemical methods

    Science.gov (United States)

    Arjunan, V.; Santhanam, R.; Marchewka, M. K.; Mohan, S.; Yang, Haifeng

    2015-11-01

    Tapentadol is a novel opioid pain reliever drug with a dual mechanism of action, having potency between morphine and tramadol. Quantum chemical calculations have been carried out for tapentadol hydrochloride (TAP.Cl) to determine the properties. The geometry is optimised and the structural properties of the compound were determined from the optimised geometry by B3LYP method using 6-311++G(d,p), 6-31G(d,p) and cc-pVDZ basis sets. FT-IR and FT-Raman spectra are recorded in the solid phase in the region of 4000-400 and 4000-100 cm-1, respectively. Frontier molecular orbital energies, LUMO-HOMO energy gap, ionisation potential, electron affinity, electronegativity, hardness and chemical potential are also calculated. The stability of the molecule arising from hyperconjugative interactions and charge delocalisation has been analysed using NBO analysis. The 1H and 13C nuclear magnetic resonance chemical shifts of the molecule are analysed.

  2. Computational molecular technology towards macroscopic chemical phenomena-molecular control of complex chemical reactions, stereospecificity and aggregate structures

    Energy Technology Data Exchange (ETDEWEB)

    Nagaoka, Masataka [Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Honmachi, Kawaguchi 332-0012 (Japan); ESICB, Kyoto University, Kyodai Katsura, Nishikyo-ku, Kyoto 615-8520 (Japan)

    2015-12-31

    A new efficient hybrid Monte Carlo (MC)/molecular dynamics (MD) reaction method with a rare event-driving mechanism is introduced as a practical ‘atomistic’ molecular simulation of large-scale chemically reactive systems. Starting its demonstrative application to the racemization reaction of (R)-2-chlorobutane in N,N-dimethylformamide solution, several other applications are shown from the practical viewpoint of molecular controlling of complex chemical reactions, stereochemistry and aggregate structures. Finally, I would like to mention the future applications of the hybrid MC/MD reaction method.

  3. Computational molecular technology towards macroscopic chemical phenomena-molecular control of complex chemical reactions, stereospecificity and aggregate structures

    International Nuclear Information System (INIS)

    A new efficient hybrid Monte Carlo (MC)/molecular dynamics (MD) reaction method with a rare event-driving mechanism is introduced as a practical ‘atomistic’ molecular simulation of large-scale chemically reactive systems. Starting its demonstrative application to the racemization reaction of (R)-2-chlorobutane in N,N-dimethylformamide solution, several other applications are shown from the practical viewpoint of molecular controlling of complex chemical reactions, stereochemistry and aggregate structures. Finally, I would like to mention the future applications of the hybrid MC/MD reaction method

  4. Design and analysis of heliostat support structure

    Energy Technology Data Exchange (ETDEWEB)

    Zang Chuncheng; Wang Zhifeng [Inst. of Electrical Engineering, CAS, BJ (China); Liu Xiaobing; Zhang Xiliang [Himin Solar Energy Group Co. Ltd, Dezhou, SD (China); Wang Yanzhong [Beijing Univ. of Aeronautics and Astronautics, BJ (China)

    2008-07-01

    The design method of the heliostat support structure with the aim of reducing the cost maximally is described in this paper. In order to guarantee the strength, stiffness and stability of the structure, dynamic performance and static performance including internal stress and distortion are analyzed by means of VSAP (Visual Structural Analysis Program) finite element computational software. Then the support structure is optimized on the basis of the analysis. (orig.)

  5. Approaches to Establishing the Chemical Structure of Extraterrestrial Organic Solids

    Science.gov (United States)

    Cody, G. D.; Alexander, C. M. OD.; Wirick, Susan

    2003-01-01

    The majority of extraterrestrial organic matter in carbonaceous chondrites resides in a chemically complex, insoluble and perhaps macromolecular phase. We have been applying a series of independent solid state NMR experiments that are designed to provide a self consistent chemical characterization of this complex material. To date we have thoroughly analyzed 8 organic residues from different meteorites, including a CR2 (EET92042), CIl(Orgueil), CM2 (Murchison), Tagish Lake, CM2 (AlH83100), CM2 (Cold Bokkefeld), CM2 (Mighei), CM3 (Y86720). In fig 1. (1)H to (13)C cross polarization NMR spectra of four of these are shown. Note that there exists an enormous range in chemistry exhibited in organic solid [evident by the breadth of the spectral features both in the aliphatic region (sp(sup 3)) and the aromatic region (sp(sup 2))]. There is also considerable differences in the carbon chemistry across the meteorite groups.

  6. Tabletop imaging of structural evolutions in chemical reactions

    CERN Document Server

    Ibrahim, Heide; Beaulieu, Samuel; Schmidt, Bruno E; Thiré, Nicolas; Bisson, Éric; Hebeisen, Christoph T; Wanie, Vincent; Giguére, Mathieu; Kieffer, Jean-Claude; Sanderson, Joseph; Schuurman, Michael S; Légaré, François

    2014-01-01

    The introduction of femto-chemistry has made it a primary goal to follow the nuclear and electronic evolution of a molecule in time and space as it undergoes a chemical reaction. Using Coulomb Explosion Imaging we have shot the first high-resolution molecular movie of a to and fro isomerization process in the acetylene cation. So far, this kind of phenomenon could only be observed using VUV light from a Free Electron Laser [Phys. Rev. Lett. 105, 263002 (2010)]. Here we show that 266 nm ultrashort laser pulses are capable of initiating rich dynamics through multiphoton ionization. With our generally applicable tabletop approach that can be used for other small organic molecules, we have investigated two basic chemical reactions simultaneously: proton migration and C=C bond-breaking, triggered by multiphoton ionization. The experimental results are in excellent agreement with the timescales and relaxation pathways predicted by new and definitively quantitative ab initio trajectory simulations.

  7. Chemical Abundance Analysis of Moving Group W11450 (Latham 1)

    CERN Document Server

    O'Connell, Julia E; Frinchaboy, Peter M

    2016-01-01

    We present elemental abundances for all seven stars in Moving Group W11450 (Latham 1) to determine if they may be chemically related. These stars appear to be both spatially and kinematically related, but no spectroscopic abundance analysis exists in literature. Abundances for eight elements were derived via equivalent width analyses of high resolution (R $\\sim$60,000), high signal-to-noise ratio ($\\langle$SNR$\\rangle\\sim$100) spectra obtained with the Otto Struve 2.1m telescope and Sandiford Echelle Spectrograph at McDonald Observatory. The large star-to-star scatter in metallicity, -0.55 $\\leq$ [Fe/H] $\\leq$ 0.06 dex ($\\sigma$= 0.25), implies these stars were not produced from the same chemically homogeneous molecular cloud, and are therefore not part of a remnant or open cluster as previously proposed. Prior to this analysis, it was suggested that two stars in the group, W11449 & W11450, are possible wide binaries. The candidate wide binary pair show similar chemical abundance patterns with not only ir...

  8. Proximate analysis, backwards stepwise regression between gross calorific value, ultimate and chemical analysis of wood.

    Science.gov (United States)

    Telmo, C; Lousada, J; Moreira, N

    2010-06-01

    The gross calorific value (GCV), proximate, ultimate and chemical analysis of debark wood in Portugal were studied, for future utilization in wood pellets industry and the results compared with CEN/TS 14961. The relationship between GCV, ultimate and chemical analysis were determined by multiple regression stepwise backward. The treatment between hardwoods-softwoods did not result in significant statistical differences for proximate, ultimate and chemical analysis. Significant statistical differences were found in carbon for National (hardwoods-softwoods) and (National-tropical) hardwoods in volatile matter, fixed carbon, carbon and oxygen and also for chemical analysis in National (hardwoods-softwoods) for F and (National-tropical) hardwoods for Br. GCV was highly positively related to C (0.79 * * *) and negatively to O (-0.71 * * *). The final independent variables of the model were (C, O, S, Zn, Ni, Br) with R(2)=0.86; F=27.68 * * *. The hydrogen did not contribute statistically to the energy content.

  9. Microarray Technology for Major Chemical Contaminants Analysis in Food: Current Status and Prospects

    OpenAIRE

    Xiaoxia Ding; Wen Zhang; Xiaofeng Hu; Qi Zhang; Peiwu Li; Zhaowei Zhang

    2012-01-01

    Chemical contaminants in food have caused serious health issues in both humans and animals. Microarray technology is an advanced technique suitable for the analysis of chemical contaminates. In particular, immuno-microarray approach is one of the most promising methods for chemical contaminants analysis. The use of microarrays for the analysis of chemical contaminants is the subject of this review. Fabrication strategies and detection methods for chemical contaminants are discussed in detail....

  10. Improved Chemical Structure-Activity Modeling Through Data Augmentation.

    Science.gov (United States)

    Cortes-Ciriano, Isidro; Bender, Andreas

    2015-12-28

    Extending the original training data with simulated unobserved data points has proven powerful to increase both the generalization ability of predictive models and their robustness against changes in the structure of data (e.g., systematic drifts in the response variable) in diverse areas such as the analysis of spectroscopic data or the detection of conserved domains in protein sequences. In this contribution, we explore the effect of data augmentation in the predictive power of QSAR models, quantified by the RMSE values on the test set. We collected 8 diverse data sets from the literature and ChEMBL version 19 reporting compound activity as pIC50 values. The original training data were replicated (i.e., augmented) N times (N ∈ 0, 1, 2, 4, 6, 8, 10), and these replications were perturbed with Gaussian noise (μ = 0, σ = σnoise) on either (i) the pIC50 values, (ii) the compound descriptors, (iii) both the compound descriptors and the pIC50 values, or (iv) none of them. The effect of data augmentation was evaluated across three different algorithms (RF, GBM, and SVM radial) and two descriptor types (Morgan fingerprints and physicochemical-property-based descriptors). The influence of all factor levels was analyzed with a balanced fixed-effect full-factorial experiment. Overall, data augmentation constantly led to increased predictive power on the test set by 10-15%. Injecting noise on (i) compound descriptors or on (ii) both compound descriptors and pIC50 values led to the highest drop of RMSEtest values (from 0.67-0.72 to 0.60-0.63 pIC50 units). The maximum increase in predictive power provided by data augmentation is reached when the training data is replicated one time. Therefore, extending the original training data with one perturbed repetition thereof represents a reasonable trade-off between the increased performance of the models and the computational cost of data augmentation, namely increase of (i) model complexity due to the need for optimizing

  11. Analysis of chemical composition of high viscous oils

    Directory of Open Access Journals (Sweden)

    Irina Germanovna Yashchenko

    2014-07-01

    Full Text Available The spatial distribution of viscous oils which are considered as an important reserve for oil-production in future were studied on base of information from global database on oil physical and chemical properties. Changes in chemical composition of viscous oils in different basins and continents were analyzed as well. It is shown, on average, viscous oils are sulfur-bearing, low paraffin, highly resinous oils with an average content of asphaltenes and low content of the fraction boiling at 200 C. Study results of viscous oils peculiarities of Canada, Russia and Venezuela are given. The analysis results can be used to determine the optimal layouts and conditions of oil transportation, to improve the search methods of geochemical exploration, and to solve other problems in the oil chemistry.

  12. Optical and structural properties of PbI2 thin film produced via chemical dipping method

    Science.gov (United States)

    Kariper, İ. A.

    2016-06-01

    PbI2 thin films were deposited on glass substrates via chemical bath deposition. The characteristics of PbI2 thin films were examined through their structural and optical properties. X-ray diffraction spectra showed the presence of rhombohedral structure and atom planes were subject to change with the pH of the bath. Scanning electron microscope indicated uniform distribution of grains. Optical properties were examined via UV-VIS; optical spectrum of the thin films was measured at the range of 200-1100 nm wavelength. Optimum pH levels for producing thin films were found to be pH 4-5. It has been observed that transmission and optical band gap ( E g) increased with the pH of the bath, which varied between 66-95 and 2.24-2.50 %, respectively; on the other hand film thickness of PbI2 thin films was decreased with the pH of the bath. Energy-dispersive X-ray spectroscopy analysis were in accordance with theoretical value of PbI2 at pH = 4 and 5. Refractive index was negatively correlated with pH of the chemical bath; it has been calculated as 1.97, 1.40, 1.29 and 1.24 for the films produced at pH 2, 3, 4 and 5. The results of the study were compared with similar studies in the literature.

  13. Collapse Analysis of Timber Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2008-01-01

    to behave robust according to the sued probabilistic approach. However, the present probabilistic approach for robustness evaluation has to be further developed for a general application to timber systems, and a simplified approach suitable for day-to-day engineering purposes must be identified....... of Structures and a probabilistic modelling of the timber material proposed in the Probabilistic Model Code (PMC) of the Joint Committee on Structural Safety (JCSS). Due to the framework in the Danish Code the timber structure has to be evaluated with respect to the following criteria where at least one shall...... to criteria a) and b) the timber frame structure has one column with a reliability index a bit lower than an assumed target level. By removal three columns one by one no significant extensive failure of the entire structure or significant parts of it are obtained. Therefore the structure can be considered...

  14. EDCs DataBank: 3D-Structure database of endocrine disrupting chemicals.

    Science.gov (United States)

    Montes-Grajales, Diana; Olivero-Verbel, Jesus

    2015-01-01

    Endocrine disrupting chemicals (EDCs) are a group of compounds that affect the endocrine system, frequently found in everyday products and epidemiologically associated with several diseases. The purpose of this work was to develop EDCs DataBank, the only database of EDCs with three-dimensional structures. This database was built on MySQL using the EU list of potential endocrine disruptors and TEDX list. It contains the three-dimensional structures available on PubChem, as well as a wide variety of information from different databases and text mining tools, useful for almost any kind of research regarding EDCs. The web platform was developed employing HTML, CSS and PHP languages, with dynamic contents in a graphic environment, facilitating information analysis. Currently EDCs DataBank has 615 molecules, including pesticides, natural and industrial products, cosmetics, drugs and food additives, among other low molecular weight xenobiotics. Therefore, this database can be used to study the toxicological effects of these molecules, or to develop pharmaceuticals targeting hormone receptors, through docking studies, high-throughput virtual screening and ligand-protein interaction analysis. EDCs DataBank is totally user-friendly and the 3D-structures of the molecules can be downloaded in several formats. This database is freely available at http://edcs.unicartagena.edu.co.

  15. Structured Sparse Principal Component Analysis

    OpenAIRE

    R. Jenatton; G. Obozinski; Bach, F.

    2009-01-01

    We present an extension of sparse PCA, or sparse dictionary learning, where the sparsity patterns of all dictionary elements are structured and constrained to belong to a prespecified set of shapes. This \\emph{structured sparse PCA} is based on a structured regularization recently introduced by [1]. While classical sparse priors only deal with \\textit{cardinality}, the regularization we use encodes higher-order information about the data. We propose an efficient and simple optimization proced...

  16. Analysis of piezoelectric structures and devices

    CERN Document Server

    Chen, Weiqiu; Wang, Ji

    2013-01-01

    This edited work covers piezoelectric materials in the form of beams, plates, shells, and other structural components in modern devices and structures. Applications are frequency control and detection functions in resonators, sensors, actuators, oscillations, and other smart and intelligent structures. The contributions cover novel methods for the analysis of piezoelectric structures including wave propagation, high frequency vibration, material characterization, and optimization of structures. Understanding of these methods is increasingly important in the design and modelling of next generat

  17. Quantum chemical and experimental studies on the structure and vibrational spectra of an alkaloid-Corlumine

    Science.gov (United States)

    Mishra, Rashmi; Joshi, Bhawani Datt; Srivastava, Anubha; Tandon, Poonam; Jain, Sudha

    2014-01-01

    The study concentrates on an important natural product, phthalide isoquinoline alkaloid Corlumine (COR) [(6R)-6-[(1S)-1,2,3,4-Tetrahydro-6,7-dimethoxy-2-methylisoquinolin-1-yl] furo [3,4-e]-1,3-benzodioxol-8(6H)-one] well known to exhibit spasmolytic and GABA antagonist activity. It was fully characterized by a variety of experimental methods including vibrational spectroscopy (IR and Raman), thermal analysis (DSC), UV and SEM. For a better interpretation and analysis of the results quantum chemical calculations employing DFT were also performed. TD-DFT was employed to elucidate electronic properties for both gaseous and solvent environment using IEF-PCM model. Graphical representation of HOMO and LUMO would provide a valuable insight into the nature of reactivity and some of the structural and physical properties of the title molecule. The structure-activity relationship have been interpreted by mapping electrostatic potential surface (MEP), which is valuable information for the quality control of medicines and drug-receptor interactions. Stability of the molecule arising from hyper conjugative interactions, charge delocalisation has been analyzed using natural bond orbital (NBO) analysis. Computation of thermodynamical properties would help to have a deep insight into the molecule for further applications.

  18. Combining QSAR Modeling and Text-Mining Techniques to Link Chemical Structures and Carcinogenic Modes of Action

    Science.gov (United States)

    Papamokos, George; Silins, Ilona

    2016-01-01

    There is an increasing need for new reliable non-animal based methods to predict and test toxicity of chemicals. Quantitative structure-activity relationship (QSAR), a computer-based method linking chemical structures with biological activities, is used in predictive toxicology. In this study, we tested the approach to combine QSAR data with literature profiles of carcinogenic modes of action automatically generated by a text-mining tool. The aim was to generate data patterns to identify associations between chemical structures and biological mechanisms related to carcinogenesis. Using these two methods, individually and combined, we evaluated 96 rat carcinogens of the hematopoietic system, liver, lung, and skin. We found that skin and lung rat carcinogens were mainly mutagenic, while the group of carcinogens affecting the hematopoietic system and the liver also included a large proportion of non-mutagens. The automatic literature analysis showed that mutagenicity was a frequently reported endpoint in the literature of these carcinogens, however, less common endpoints such as immunosuppression and hormonal receptor-mediated effects were also found in connection with some of the carcinogens, results of potential importance for certain target organs. The combined approach, using QSAR and text-mining techniques, could be useful for identifying more detailed information on biological mechanisms and the relation with chemical structures. The method can be particularly useful in increasing the understanding of structure and activity relationships for non-mutagens. PMID:27625608

  19. Combining QSAR Modeling and Text-Mining Techniques to Link Chemical Structures and Carcinogenic Modes of Action.

    Science.gov (United States)

    Papamokos, George; Silins, Ilona

    2016-01-01

    There is an increasing need for new reliable non-animal based methods to predict and test toxicity of chemicals. Quantitative structure-activity relationship (QSAR), a computer-based method linking chemical structures with biological activities, is used in predictive toxicology. In this study, we tested the approach to combine QSAR data with literature profiles of carcinogenic modes of action automatically generated by a text-mining tool. The aim was to generate data patterns to identify associations between chemical structures and biological mechanisms related to carcinogenesis. Using these two methods, individually and combined, we evaluated 96 rat carcinogens of the hematopoietic system, liver, lung, and skin. We found that skin and lung rat carcinogens were mainly mutagenic, while the group of carcinogens affecting the hematopoietic system and the liver also included a large proportion of non-mutagens. The automatic literature analysis showed that mutagenicity was a frequently reported endpoint in the literature of these carcinogens, however, less common endpoints such as immunosuppression and hormonal receptor-mediated effects were also found in connection with some of the carcinogens, results of potential importance for certain target organs. The combined approach, using QSAR and text-mining techniques, could be useful for identifying more detailed information on biological mechanisms and the relation with chemical structures. The method can be particularly useful in increasing the understanding of structure and activity relationships for non-mutagens. PMID:27625608

  20. Modeling turbulence structure. Chemical kinetics interaction in turbulent reactive flows

    Energy Technology Data Exchange (ETDEWEB)

    Magnussen, B.F. [The Norwegian Univ. of Science and Technology, Trondheim (Norway)

    1997-12-31

    The challenge of the mathematical modelling is to transfer basic physical knowledge into a mathematical formulation such that this knowledge can be utilized in computational simulation of practical problems. The combustion phenomena can be subdivided into a large set of interconnected phenomena like flow, turbulence, thermodynamics, chemical kinetics, radiation, extinction, ignition etc. Combustion in one application differs from combustion in another area by the relative importance of the various phenomena. The difference in fuel, geometry and operational conditions often causes the differences. The computer offers the opportunity to treat the individual phenomena and their interactions by models with wide operational domains. The relative magnitude of the various phenomena therefore becomes the consequence of operational conditions and geometry and need not to be specified on the basis of experience for the given problem. In mathematical modelling of turbulent combustion, one of the big challenges is how to treat the interaction between the chemical reactions and the fluid flow i.e. the turbulence. Different scientists adhere to different concepts like the laminar flamelet approach, the pdf approach of the Eddy Dissipation Concept. Each of these approaches offers different opportunities and problems. All these models are based on a sound physical basis, however none of these have general validity in taking into consideration all detail of the physical chemical interaction. The merits of the models can only be judged by their ability to reproduce physical reality and consequences of operational and geometric conditions in a combustion system. The presentation demonstrates and discusses the development of a coherent combustion technology for energy conversion and safety based on the Eddy Dissipation Concept by Magnussen. (author) 30 refs.

  1. Epithelial structure revealed by chemical dissection and unembedded electron microscopy

    OpenAIRE

    Fey, E G; Capco, D G; Krochmalnic, G; Penman, S

    1984-01-01

    Cytoskeletal structures obtained after extraction of Madin-Darby canine kidney epithelial cell monolayers with Triton X-100 were examined in transmission electron micrographs of cell whole mounts and unembedded thick sections. The cytoskeleton, an ordered structure consisting of a peripheral plasma lamina, a complex network of filaments, and chromatin-containing nuclei, was revealed after extraction of intact cells with a nearly physiological buffer containing Triton X-100. The cytoskeleton w...

  2. Chemical Tuning of the Magnetic Interactions in Layer Structures

    OpenAIRE

    Ronneteg, Sabina

    2005-01-01

    Thin metal films have found their use in many magnetic devices. They form pseudo two-dimensional systems, where the mechanisms for the magnetic interactions between the layers are not completely understood. Layered crystal structures have an advantage over such artificial systems, since the layers can be strictly mono-atomic without any unwanted admixture. In this study, some model systems of layered magnetic crystal structures and their solid solutions have been investigated by x-ray and neu...

  3. Robustness Analysis of Kinetic Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2009-01-01

    Kinetic structures in architecture follows a new trend which is emerging in responsive architecture coined by Nicholas Negroponte when he proposed that architecture may benefit from the integration of computing power into built spaces and structures, and that better performing, more rational buil...

  4. QUALITY ASSURANCE GUIDELINES FOR LABORATORIES PERFORMING FORENSIC ANALYSIS OF CHEMICAL TERRORISM

    Science.gov (United States)

    The Scientific Working Group on Forensic Analysis of Chemical Terrorism (SWGFACT) has developed the following quality assurance guidelines to provide laboratories engaged in forensic analysis of chemical evidence associated with terrorism a framework to implement a quality assura...

  5. WebChem Viewer: a tool for the easy dissemination of chemical and structural data sets

    OpenAIRE

    Durrant, Jacob D; Rommie E Amaro

    2014-01-01

    Background Sharing sets of chemical data (e.g., chemical properties, docking scores, etc.) among collaborators with diverse skill sets is a common task in computer-aided drug design and medicinal chemistry. The ability to associate this data with images of the relevant molecular structures greatly facilitates scientific communication. There is a need for a simple, free, open-source program that can automatically export aggregated reports of entire chemical data sets to files viewable on any c...

  6. Structuring of DLC:Ag nanocomposite thin films employing plasma chemical etching and ion sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Tamulevičius, Tomas, E-mail: Tomas.Tamulevicius@ktu.lt; Tamulevičienė, Asta; Virganavičius, Dainius; Vasiliauskas, Andrius; Kopustinskas, Vitoldas; Meškinis, Šarūnas; Tamulevičius, Sigitas

    2014-12-15

    Highlights: • CF{sub 4}/O{sub 2} dry etching of DLC:Ag films revealed the embedded Ag nanoparticles. • Plasma processed samples with more than 5 at.% Ag demonstrated Ostwald ripening. • 4 μm period patterns in aluminum and photoresist were imposed in the DLC:Ag film. • Different micro patterns are formed depending on the selected processing route. - Abstract: We analyze structuring effects of diamond like carbon based silver nanocomposite (DLC:Ag) thin films by CF{sub 4}/O{sub 2} plasma chemical etching and Ar{sup +} sputtering. DLC:Ag films were deposited employing unbalanced reactive magnetron sputtering of silver target with Ar{sup +} in C{sub 2}H{sub 2} gas atmosphere. Films with different silver content (0.6–12.9 at.%) were analyzed. The films (as deposited and exposed to plasma chemical etching) were characterized employing scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDS), optical microscopy, ultraviolet–visible light (UV–VIS) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. After deposition, the films were plasma chemically etched in CF{sub 4}/O{sub 2} mixture plasma for 2–6 min. It is shown that optical properties of thin films and silver nano particle size distribution can be tailored during deposition changing the magnetron current and C{sub 2}H{sub 2}/Ar ratio or during following plasma chemical etching. The plasma etching enabled to reveal the silver filler particle size distribution and to control silver content on the surface that was found to be dependent on Ostwald ripening process of silver nano-clusters. Employing contact lithography and 4 μm period mask in photoresist or aluminum the films were patterned employing CF{sub 4}/O{sub 2} mixture plasma chemical etching, direct Ar{sup +} sputtering or combined etching processes. It is shown that different processing recipes result in different final grating structures. Selective carbon etching in CF{sub 4}/O{sub 2} gas mixture with

  7. Probabilistic Approach to Risk Analysis of Chemical Spills at Sea

    Institute of Scientific and Technical Information of China (English)

    Magda Bogalecka; Krzysztof Kolowrocki

    2006-01-01

    Risk analysis of chemical spills at sea and their consequences for sea environment are discussed. Mutual interactions between the process of the sea accident initiating events, the process of the sea environment threats, and the process of the sea environment degradation are investigated. To describe these three particular processes, the separate semi-Markov models are built. Furthermore, these models are jointed into one general model of these processes interactions.Moreover, some comments on the method for statistical identification of the considered models are proposed.

  8. Physcio chemical analysis of browning inhibitors treated solanum turberosum powder

    International Nuclear Information System (INIS)

    White potatoes (Solanum turberosum) were procured from agriculture Research Institute Tarnab Farm Peshawar to use for the preparation of potato powder. The process involves sorting. Washing, peeling slicing, blanching, treating with poly phenol oxidase inhibitors, dehydration, grinding and packing. All these parameters used in process were standardized. Chemical analysis of fresh potato and potato powder were carried out. Microbiological examination, functional properties and storage life studies of the potato powder were also performed. The product prepared by drying in cabinet dryer at 55 C for 7 hours was off white colour potatoes chips which was grinded to make off white potato powder. The potato powder possessed taste and texture. (author)

  9. Crystal-Chemical Analysis of Soil at Rocknest, Gale Crater

    Science.gov (United States)

    Morrison, S. M.; Downs, R. T.; Blake, D. F.; Bish, D. L.; Ming, D. W.; Morris, R. V.; Yen, A. S.; Chipera, S. J.; Treiman, A. H.; Vaniman, D. T.; Gellert, R.; Achilles, C. N.; Rampe, E. B.; Bristow, T. F.; Crisp, J. A.; Sarrazin, P. C.; DesMarais, D. J.; Morookian, J. M.; Anderson, R. C.

    2013-01-01

    The CheMin instrument on the Mars Science Laboratory rover Curiosity performed X-ray diffraction analysis on Martian soil [1] at Rocknest in Gale Crater. In particular, crystalline phases from scoop 5 were identified and analyzed with the Rietveld method [2]. Refined unit-cell parameters are reported in Table 1. Comparing these unit-cell parameters with those in the literature provides an estimate of the chemical composition of the crystalline phases. For instance, Fig. 1 shows the Mg-content of Fa-Fo olivine as a function of the b unit-cell parameter using literature data. Our refined b parameter is indicated by the black triangle.

  10. A robust algorithm for optimizing protein structures with NMR chemical shifts.

    Science.gov (United States)

    Berjanskii, Mark; Arndt, David; Liang, Yongjie; Wishart, David S

    2015-11-01

    Over the past decade, a number of methods have been developed to determine the approximate structure of proteins using minimal NMR experimental information such as chemical shifts alone, sparse NOEs alone or a combination of comparative modeling data and chemical shifts. However, there have been relatively few methods that allow these approximate models to be substantively refined or improved using the available NMR chemical shift data. Here, we present a novel method, called Chemical Shift driven Genetic Algorithm for biased Molecular Dynamics (CS-GAMDy), for the robust optimization of protein structures using experimental NMR chemical shifts. The method incorporates knowledge-based scoring functions and structural information derived from NMR chemical shifts via a unique combination of multi-objective MD biasing, a genetic algorithm, and the widely used XPLOR molecular modelling language. Using this approach, we demonstrate that CS-GAMDy is able to refine and/or fold models that are as much as 10 Å (RMSD) away from the correct structure using only NMR chemical shift data. CS-GAMDy is also able to refine of a wide range of approximate or mildly erroneous protein structures to more closely match the known/correct structure and the known/correct chemical shifts. We believe CS-GAMDy will allow protein models generated by sparse restraint or chemical-shift-only methods to achieve sufficiently high quality to be considered fully refined and "PDB worthy". The CS-GAMDy algorithm is explained in detail and its performance is compared over a range of refinement scenarios with several commonly used protein structure refinement protocols. The program has been designed to be easily installed and easily used and is available at http://www.gamdy.ca.

  11. A robust algorithm for optimizing protein structures with NMR chemical shifts

    Energy Technology Data Exchange (ETDEWEB)

    Berjanskii, Mark; Arndt, David; Liang, Yongjie; Wishart, David S., E-mail: david.wishart@ualberta.ca [University of Alberta, Department of Computing Science (Canada)

    2015-11-15

    Over the past decade, a number of methods have been developed to determine the approximate structure of proteins using minimal NMR experimental information such as chemical shifts alone, sparse NOEs alone or a combination of comparative modeling data and chemical shifts. However, there have been relatively few methods that allow these approximate models to be substantively refined or improved using the available NMR chemical shift data. Here, we present a novel method, called Chemical Shift driven Genetic Algorithm for biased Molecular Dynamics (CS-GAMDy), for the robust optimization of protein structures using experimental NMR chemical shifts. The method incorporates knowledge-based scoring functions and structural information derived from NMR chemical shifts via a unique combination of multi-objective MD biasing, a genetic algorithm, and the widely used XPLOR molecular modelling language. Using this approach, we demonstrate that CS-GAMDy is able to refine and/or fold models that are as much as 10 Å (RMSD) away from the correct structure using only NMR chemical shift data. CS-GAMDy is also able to refine of a wide range of approximate or mildly erroneous protein structures to more closely match the known/correct structure and the known/correct chemical shifts. We believe CS-GAMDy will allow protein models generated by sparse restraint or chemical-shift-only methods to achieve sufficiently high quality to be considered fully refined and “PDB worthy”. The CS-GAMDy algorithm is explained in detail and its performance is compared over a range of refinement scenarios with several commonly used protein structure refinement protocols. The program has been designed to be easily installed and easily used and is available at http://www.gamdy.ca http://www.gamdy.ca.

  12. Poly(ADP-ribose)--a unique natural polymer structural features, biological role and approaches to the chemical synthesis.

    Science.gov (United States)

    Drenichev, Mikhail S; Mikhailov, Sergey N

    2015-01-01

    Poly(ADP-ribose) (PAR) is a natural polymer, taking part in numerous important cellular processes. Several enzymes are involved in biosynthesis and degradation of PAR. One of them, poly(ADP-ribose)polymerase-1 (PARP-1) is considered to be a perspective target for the design of new drugs, affecting PAR metabolism. The structure of PAR was established by enzymatic hydrolysis and further analysis of the products, but total chemical synthesis of PAR hasn't been described yet. Several approaches have been developed on the way to chemical synthesis of this unique biopolymer.

  13. Nonlinear structural analysis using integrated force method

    Indian Academy of Sciences (India)

    N R B Krishnam Raju; J Nagabhushanam

    2000-08-01

    Though the use of the integrated force method for linear investigations is well-recognised, no efforts were made to extend this method to nonlinear structural analysis. This paper presents the attempts to use this method for analysing nonlinear structures. General formulation of nonlinear structural analysis is given. Typically highly nonlinear bench-mark problems are considered. The characteristic matrices of the elements used in these problems are developed and later these structures are analysed. The results of the analysis are compared with the results of the displacement method. It has been demonstrated that the integrated force method is equally viable and efficient as compared to the displacement method.

  14. Integrated chemical-thermal and laser treatment of structural and tool steels

    International Nuclear Information System (INIS)

    Using the techniques of autoradiography, radiography, metallography and micro hardness measurement, the distribution of boron and the surface hardening of structural and tool steels under complex chemical, thermal and laser treatment have been investigated

  15. CHEMICAL STRUCTURE INDEXING OF TOXICITY DATA ON THE INTERNET: MOVING TOWARDS A FLAT WORLD

    Science.gov (United States)

    Standardized chemical structure annotation of public toxicity databases and information resources is playing an increasingly important role in the 'flattening' and integration of diverse sets of biological activity data on the Internet. This review discusses public initiatives th...

  16. Neutron diffraction analysis of crystal magnetic structures

    International Nuclear Information System (INIS)

    An investigation of the state-of-the art of the neutron diffraction analysis of magnetic structures from the point of view of the theory of crystal symmetry is given. Various and numerous structures determined from the neutron diffraction analysis investigations can be classified and described with the theory of space group representations of crystals. The analysis of quite a number of various magnetic structures shows that they arise according to Landau hypothesis. The foundations of a symmetry analysis of magnetic structures and the methods for their determination are given. A physical explanation is given for the existence of magnetic structures. The experimental investigations of the crystal lattice distortions accompanying a magnetic ordering are reviewed. In this review is given a symmetry approach to the description of the magnetic structures of crystals; and a possibility to analyze them by a scattering of nonpolarized and polarized neutrons

  17. Radial size and chemical structure of nuclear tracks in polymers

    International Nuclear Information System (INIS)

    The radial size of track cores in CR-39 plastics for several types of ions has been determined by two different methods. First, atomic force microscope (AFM) observations were performed on the irradiated CR-39 subsequent to the slight chemical etchings. The track core radii for C, O, Ne and Xe ions evaluated from the intersections of the extrapolated lines, fitted to each growth curve of etch pit radius, were found to be in the range between 2.8 and 4.1 nm, independent of the ion species. Second, ultraviolet (UV)-visible spectra of the irradiated CR-39 were obtained at various fluences. Based on a track overlapping model, the track core radii are evaluated for Ne, Ar, Si and Fe ions. Their core radii were almost proportional to the cube root of the stopping power. The results from the two different measurements are in good agreement with each other. (author)

  18. Recognition and repair of chemically heterogeneous structures at DNA ends.

    Science.gov (United States)

    Andres, Sara N; Schellenberg, Matthew J; Wallace, Bret D; Tumbale, Percy; Williams, R Scott

    2015-01-01

    Exposure to environmental toxicants and stressors, radiation, pharmaceutical drugs, inflammation, cellular respiration, and routine DNA metabolism all lead to the production of cytotoxic DNA strand breaks. Akin to splintered wood, DNA breaks are not "clean." Rather, DNA breaks typically lack DNA 5'-phosphate and 3'-hydroxyl moieties required for DNA synthesis and DNA ligation. Failure to resolve damage at DNA ends can lead to abnormal DNA replication and repair, and is associated with genomic instability, mutagenesis, neurological disease, ageing and carcinogenesis. An array of chemically heterogeneous DNA termini arises from spontaneously generated DNA single-strand and double-strand breaks (SSBs and DSBs), and also from normal and/or inappropriate DNA metabolism by DNA polymerases, DNA ligases and topoisomerases. As a front line of defense to these genotoxic insults, eukaryotic cells have accrued an arsenal of enzymatic first responders that bind and protect damaged DNA termini, and enzymatically tailor DNA ends for DNA repair synthesis and ligation. These nucleic acid transactions employ direct damage reversal enzymes including Aprataxin (APTX), Polynucleotide kinase phosphatase (PNK), the tyrosyl DNA phosphodiesterases (TDP1 and TDP2), the Ku70/80 complex and DNA polymerase β (POLβ). Nucleolytic processing enzymes such as the MRE11/RAD50/NBS1/CtIP complex, Flap endonuclease (FEN1) and the apurinic endonucleases (APE1 and APE2) also act in the chemical "cleansing" of DNA breaks to prevent genomic instability and disease, and promote progression of DNA- and RNA-DNA damage response (DDR and RDDR) pathways. Here, we provide an overview of cellular first responders dedicated to the detection and repair of abnormal DNA termini. PMID:25111769

  19. Review of selective accumudation of photosensitizers with different chemical structure in tumor tissue

    Directory of Open Access Journals (Sweden)

    E. A. Machinskaya

    2013-01-01

    Full Text Available The review of available theories explaining mechanisms of photosensitizer selective accumulation in tumor tissue is represented in the article. Variants associated with both targeted delivery of compounds with different chemical structure to tumor and low elimination rate of photosensitizers in the tumor are described. Details of tumor cell up-take of photosensitizer bounded with lipoproteins due to increased expression of low solidity lipoproteins receptors comparing with normal cells; mechanisms of photosensitizer accumulation in tumor tissue due to phagocytosis by macrophages localized in this area; mechanisms of binding of porphyrin-based photosensitizer by collagen fibers, production of which is increased in tumor cells, and other mechanisms are reviewed. Perspectives of practical application of knowledge about mechanisms of selective accumulation for induced increase in selectiveness of photosensitizer accumulation in tumor through targeted delivery of agent to pathological tissues are shown. Analysis of world trends in the search of transport systems for photosensitizers is performed. 

  20. Combinations of protein-chemical complex structures reveal new targets for established drugs.

    OpenAIRE

    Kalinina, Olga V.; Oliver Wichmann; Gordana Apic; Russell, Robert B.

    2011-01-01

    Biological networks are powerful tools for predicting undocumented relationships between molecules. The underlying principle is that existing interactions between molecules can be used to predict new interactions. Here we use this principle to suggest new protein-chemical interactions via the network derived from three-dimensional structures. For pairs of proteins sharing a common ligand, we use protein and chemical superimpositions combined with fast structural compatibility screens to predi...

  1. The structure and local chemical properties of boron-terminated tetravacancies in hexagonal boron-nitride

    OpenAIRE

    Cretu, Ovidiu; Lin, Yung-Chang; Koshino, Masanori; Tizei, Luiz H. G.; Liu, Zheng; Suenaga, Kazutomo

    2014-01-01

    Imaging and spectroscopy performed in a low-voltage scanning transmission electron microscope (LV-STEM) are used to characterize the structure and chemical properties of boron-terminated tetravacancies in hexagonal boron nitride (h-BN). We confirm earlier theoretical predictions about the structure of these defects and identify new features in the electron energy-loss spectra (EELS) of B atoms using high resolution chemical maps, highlighting differences between these areas and pristine sampl...

  2. Microbiological and chemical analysis of land snails commercialised in Sicily

    Directory of Open Access Journals (Sweden)

    Antonello Cicero

    2015-05-01

    Full Text Available In this study 160 samples of snails belonging to the species Helix aspersa maxima and Helix aspersa muller were examined for chemical and microbiological analysis. Samples came from Greece and Poland. Results showed mean concentration of cadmium (0.35±0.036 mg/kg and lead (0.05±0.013 mg/kg much higher than the limit of detection. Mercury levels in both species were not detected. Microbiological analysis revealed the absence of Salmonella spp. and Clostridium spp. in both examined species. E. coli and K. oxytoca were observed in Helix aspersa maxima and Helix aspersa muller. Furthermore, one case of fungi positivity in samples of Helix aspersa muller was found. The reported investigations highlight the need to create and adopt a reference legislation to protect the health of consumers.

  3. Statistical sampling and chemical analysis of complex weapon components

    International Nuclear Information System (INIS)

    One of the waste streams generated by nuclear weapon dismantlement programs will be component ''hardware'', including complex electronic assemblies such as: radars, arming/fusing/firing systems, power sources, and use-control and safety systems. Sandia National Laboratories (SNL) has been the design and development laboratory for many of these components and will be responsible for their ultimate disposition. This disposition, whether it be reuse, material recycle, or disposal, will require some level of material characterization and analysis. Previous efforts at developing a process for segregation and characterization of hazardous materials in weapon components have been documented. This paper describes the results of recent activities undertaken in support of the Weapon Hardware Inventory Reduction Effort (WHIRE) at Sandia National Laboratories. These activities have been directed principally towards: The development of a statistically sound sampling plan for chemical analysis of weapon component materials; the development of a non-destructive analytical screening method for determining the Toxicity Characteristic of excess weapon hardware

  4. Theoretical study of the electronic structure of f-element complexes by quantum chemical methods

    International Nuclear Information System (INIS)

    This thesis is related to comparative studies of the chemical properties of molecular complexes containing lanthanide or actinide trivalent cations, in the context of the nuclear waste disposal. More precisely, our aim was a quantum chemical analysis of the metal-ligand bonding in such species. Various theoretical approaches were compared, for the inclusion of correlation (density functional theory, multiconfigurational methods) and of relativistic effects (relativistic scalar and 2-component Hamiltonians, relativistic pseudopotentials). The performance of these methods were checked by comparing computed structural properties to published experimental data, on small model systems: lanthanide and actinide tri-halides and on X3M-L species (X=F, Cl; M=La, Nd, U; L = NH3, acetonitrile, CO). We have thus shown the good performance of density functionals combined with a quasi-relativistic method, as well as of gradient-corrected functionals associated with relativistic pseudopotentials. In contrast, functionals including some part of exact exchange are less reliable to reproduce experimental trends, and we have given a possible explanation for this result . Then, a detailed analysis of the bonding has allowed us to interpret the discrepancies observed in the structural properties of uranium and lanthanides complexes, based on a covalent contribution to the bonding, in the case of uranium(III), which does not exist in the lanthanide(III) homologues. Finally, we have examined more sizeable systems, closer to experimental species, to analyse the influence of the coordination number, of the counter-ions and of the oxidation state of uranium, on the metal-ligand bonding. (author)

  5. Structural Analysis of the Upper Internal Structure in PGSFR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. H.; Koo, G. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The upper internal structure (UIS) is a package of hardware suspended from the rotating plug to about 20 cm above the core assemblies. The functions of the UIS are to support shroud tubes containing the primary and secondary control rod drivelines and preserve critical alignments between these drivelines and the core lattice, under normal and off-normal conditions. In addition, the UIS produces sufficient coolant mixing to mitigate thermal transients to downstream components and provides an opening for the In-Vessel transfer machine to access inner core positions without interfacing with the control rod drive lines and the upper core instrumentation package. The radial position of the shroud tube is fixed by three horizontal guide plates and the lower guide plate is close to the core assemblies and is perforated to permit most of the core effluent to reach the region between guide plates. In this study, the primary stress analysis for dead weight was carried out and the thermal stress analysis considering the coolant temperature around the UIS was performed. In addition, the mode characteristics of the structure by the natural frequency analysis were evaluated. The structural analysis model is developed to evaluate the structural integrity of the UIS. The primary stress analysis, the thermal stress analysis and the natural frequency analysis for the UIS are performed, and the maximum stresses and displacements are evaluated. From the analysis results, it is confirmed that the large local stresses don't occur near the holes and through the wall thicknesses of the structure. In addition, the maximum temperature of the UIS is calculated as 545 .deg. C from the thermal analysis and the structure should be evaluated by the ASME design rules at a high temperature. In the future, the more detailed design will be performed by the high temperature evaluation procedure according to the ASME SEC. III, Div.5.

  6. Probabilistic structural analysis by extremum methods

    Science.gov (United States)

    Nafday, Avinash M.

    1990-01-01

    The objective is to demonstrate discrete extremum methods of structural analysis as a tool for structural system reliability evaluation. Specifically, linear and multiobjective linear programming models for analysis of rigid plastic frames under proportional and multiparametric loadings, respectively, are considered. Kinematic and static approaches for analysis form a primal-dual pair in each of these models and have a polyhedral format. Duality relations link extreme points and hyperplanes of these polyhedra and lead naturally to dual methods for system reliability evaluation.

  7. Chemical Analysis of Wastewater from Unconventional Drilling Operations

    Directory of Open Access Journals (Sweden)

    Jonathan B. Thacker

    2015-04-01

    Full Text Available Trillions of liters of wastewater from oil and gas extraction are generated annually in the US. The contribution from unconventional drilling operations (UDO, such as hydraulic fracturing, to this volume will likely continue to increase in the foreseeable future. The chemical content of wastewater from UDO varies with region, operator, and elapsed time after production begins. Detailed chemical analyses may be used to determine its content, select appropriate treatment options, and identify its source in cases of environmental contamination. In this study, one wastewater sample each from direct effluent, a disposal well, and a waste pit, all in West Texas, were analyzed by gas chromatography-mass spectrometry, inductively coupled plasma-optical emission spectroscopy, high performance liquid chromatography-high resolution mass spectrometry, high performance ion chromatography, total organic carbon/total nitrogen analysis, and pH and conductivity analysis. Several compounds known to compose hydraulic fracturing fluid were detected among two of the wastewater samples including 2-butoxyethanol, alkyl amines, and cocamide diethanolamines, toluene, and o-xylene. Due both to its quantity and quality, proper management of wastewater from UDO will be essential.

  8. Cosmetics chemical composition characterization by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Brazil is in the third position in the world's cosmetics market. It is an expanding and growing market where new products and manufacturing processes are in a constant and steady expansion. Therefore, it is mandatory that the composition of the products is well known in order to guarantee safety and quality of daily used cosmetics. The Brazilian National Health Surveillance Agency (ANVISA) has issued a resolution, RDC No. 48, March 16, 2006, which defines a 'List of Substances which can not be used in personal hygiene products, cosmetics and perfumes'. In this work, samples of locally manufactured and imported cosmetics (lipsticks, eye shadows, etc.) were analyzed using the Instrumental Neutron Activation Analysis technique. The samples were irradiated in the TRIGA IPR-R1 reactor of the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN), on a 100kW thermal power, with a thermal neutron fluence rate about 8x1011ncm-2s-1. The analysis has detected the chemical elements Br, Ba, Ga, Na, K, Sc, Fe, Cr, Zn, Sm, W, La, Rb, Cs, Ta, Ge, Co, U, Ti, V, Cl, Al, Mn and Cu. The concentrations of these elements are on a range from 5 to 3000μg.g-1. Some chemical elements observed in samples (Cl, Br, Cr, U) are included at ANVISA prohibitive list. (author)

  9. X-ray photoelectron spectra structure and chemical bonding in AmO2

    Directory of Open Access Journals (Sweden)

    Teterin Yury A.

    2015-01-01

    Full Text Available Quantitative analysis was done of the X-ray photoelectron spectra structure in the binding energy range of 0 eV to ~35 eV for americium dioxide (AmO2 valence electrons. The binding energies and structure of the core electronic shells (~35 eV-1250 eV, as well as the relativistic discrete variation calculation results for the Am63O216 and AmO8 (D4h cluster reflecting Am close environment in AmO2 were taken into account. The experimental data show that the many-body effects and the multiplet splitting contribute to the spectral structure much less than the effects of formation of the outer (0-~15 eV binding energy and the inner (~15 eV-~35 eV binding energy valence molecular orbitals. The filled Am 5f electronic states were shown to form in the AmO2 valence band. The Am 6p electrons participate in formation of both the inner and the outer valence molecular orbitals (bands. The filled Am 6p3/2 and the O 2s electronic shells were found to make the largest contributions to the formation of the inner valence molecular orbitals. Contributions of electrons from different molecular orbitals to the chemical bond in the AmO8 cluster were evaluated. Composition and sequence order of molecular orbitals in the binding energy range 0-~35 eV in AmO2 were established. The experimental and theoretical data allowed a quantitative scheme of molecular orbitals for AmO2, which is fundamental for both understanding the chemical bond nature in americium dioxide and the interpretation of other X-ray spectra of AmO2.

  10. A broad chemical and structural characterization of the damaged region of carbon implanted alumina

    International Nuclear Information System (INIS)

    As candidate materials for future thermonuclear fusion reactors, isolating ceramics will be submitted to high energy gamma and neutron radiation fluxes together with an intense particle flux. Amorphization cannot be tolerated in ceramics for fusion applications, due to the associated volume change and the deterioration of mechanical properties. Therefore, a comprehensive study was carried out to examine the effects of carbon beam irradiation on polycrystalline aluminium oxide (Al2O3), a ceramic component of some diagnostic and plasma heating systems. Complementary techniques have allowed a complete chemical and structural surface analysis of the implanted alumina. Implantation with 75 keV, mono-energetic carbon ions at doses of 1 x 1017 and 5 x 1017 ions/cm2 was performed on polished and thermally treated ceramic discs. The alumina targets were kept below 120 deg. C. The structural modifications induced during ion irradiation were studied by the GXRD and TEM techniques. Under these conditions, alumina is readily amorphized by carbon ions, the thickness of the ion-beam induced disordered area increasing with the ion dose. Matrix elements and ion implanted profiles were followed as a function of depth by using ToF-SIMS, indicating the maximum concentration of implanted ions to be in the deeper half of the amorphous region. Ion distribution and chemical modifications caused in the Al2O3 substrate by carbon irradiation were corroborated with XPS. The amount of oxygen in the vicinity of the implanted alumina surface was reduced, suggesting that this element was selectively sputtered during carbon irradiation. The intensity of those peaks referring to Al-O bonds diminishes, while contributions of reduced aluminium and metal carbides are found at the maximum of the carbon distribution. TEM observations on low temperature thermally annealed specimens indicate partial recovery of the initial crystalline structure.

  11. A broad chemical and structural characterization of the damaged region of carbon implanted alumina

    Science.gov (United States)

    González, M.; Román, R.; Maffiotte, C.; González-Casablanca, J.; Perez, R.; Hole, D.

    2009-05-01

    As candidate materials for future thermonuclear fusion reactors, isolating ceramics will be submitted to high energy gamma and neutron radiation fluxes together with an intense particle flux. Amorphization cannot be tolerated in ceramics for fusion applications, due to the associated volume change and the deterioration of mechanical properties. Therefore, a comprehensive study was carried out to examine the effects of carbon beam irradiation on polycrystalline aluminium oxide (Al2O3), a ceramic component of some diagnostic and plasma heating systems. Complementary techniques have allowed a complete chemical and structural surface analysis of the implanted alumina. Implantation with 75 keV, mono-energetic carbon ions at doses of 1 × 1017 and 5 × 1017 ions/cm2 was performed on polished and thermally treated ceramic discs. The alumina targets were kept below 120 °C. The structural modifications induced during ion irradiation were studied by the GXRD and TEM techniques. Under these conditions, alumina is readily amorphized by carbon ions, the thickness of the ion-beam induced disordered area increasing with the ion dose. Matrix elements and ion implanted profiles were followed as a function of depth by using ToF-SIMS, indicating the maximum concentration of implanted ions to be in the deeper half of the amorphous region. Ion distribution and chemical modifications caused in the Al2O3 substrate by carbon irradiation were corroborated with XPS. The amount of oxygen in the vicinity of the implanted alumina surface was reduced, suggesting that this element was selectively sputtered during carbon irradiation. The intensity of those peaks referring to Al-O bonds diminishes, while contributions of reduced aluminium and metal carbides are found at the maximum of the carbon distribution. TEM observations on low temperature thermally annealed specimens indicate partial recovery of the initial crystalline structure.

  12. Boron carbide: Consistency of components, lattice parameters, fine structure and chemical composition makes the complex structure reasonable

    Science.gov (United States)

    Werheit, Helmut

    2016-10-01

    The complex, highly distorted structure of boron carbide is composed of B12 and B11C icosahedra and CBC, CBB and B□B linear elements, whose concentration depends on the chemical composition each. These concentrations are shown to be consistent with lattice parameters, fine structure data and chemical composition. The respective impacts on lattice parameters are estimated and discussed. Considering the contributions of the different structural components to the energy of the overall structure makes the structure and its variation within the homogeneity range reasonable; in particular that of B4.3C representing the carbon-rich limit of the homogeneity range. Replacing in B4.3C virtually the B□B components by CBC yields the hypothetical moderately distorted B4.0C (structure formula (B11C)CBC). The reduction of lattice parameters related is compatible with recently reported uncommonly prepared single crystals, whose compositions deviate from B4.3C.

  13. FINITE ELEMENT ANALYSIS OF STRUCTURES

    Directory of Open Access Journals (Sweden)

    PECINGINA OLIMPIA-MIOARA

    2015-05-01

    Full Text Available The application of finite element method is analytical when solutions can not be applied for deeper study analyzes static, dynamic or other types of requirements in different points of the structures .In practice it is necessary to know the behavior of the structure or certain parts components of the machine under the influence of certain factors static and dynamic . The application of finite element in the optimization of components leads to economic growth , to increase reliability and durability organs studied, thus the machine itself.

  14. STATIC ANALYSIS OF CABLE STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    HUANG Yan; LAN Wei-ren

    2006-01-01

    Based on the nonlinear geometric relation between strain and displacement for flexible cable, the equilibrium equation under self-weight and influence of temperature was established and an analytical solution of displacement and tension distribution defined in Eulerian coordinate system was accurately obtained. The nonlinear algebraic equations caused by cable structure were solved directly using the modified Powell hybrid algorithm with high precision routine DNEQNE of Fortran. For example, a cable structure consisting of three cables jointly supported by a vertical spring and all the other ends fixed was calculated and compared with various methods by other scholars.

  15. Surface chemical structure of titania-silica nanocomposite powder

    Institute of Scientific and Technical Information of China (English)

    WANG LuYan; SUN YanPing; XU BingShe

    2008-01-01

    Titania-silica (TS) nanocomposite powder with three different composite structures, containing 10-30 mol% SiO2 in each structure, have been prepared by sol-gel processes. The surface characteristics of these titania-silica samples have been investigated by X-ray photo-emission spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM). The study for all TS oxides annealed at 773 and 1173 K showed: an abnormal surface enrichment in Si increased with increasing annealing tem-perature; the Ti3+, Ti2+, Si3+ and Si2+ oxides coexisted with Ti4+ and Si4+ oxides, and the contents of these TilSi suboxides increased with increasing SiO2 content and annealing temperature; there was a layer rich in O on the topmost surface and the excess O could be attributed to the chem-adsorption of H2O; different composite structures could lead to different contents of Ti/Si suboxides. These results indi-cated that the surface of TS oxide powder derived by sol-gel process was a double layer with enriched O first and then SiOx/TiOy(x, y<2). Ti/Si suboxides could result from the thermal diffusion of Ti4+ and Si4+, which might be induced by the strong interaction between Ti4+ and Si4+.

  16. Shallow nitrogen ion implantation: Evolution of chemical state and defect structure in titanium

    Science.gov (United States)

    Manojkumar, P. A.; Chirayath, V. A.; Balamurugan, A. K.; Krishna, Nanda Gopala; Ilango, S.; Kamruddin, M.; Amarendra, G.; Tyagi, A. K.; Raj, Baldev

    2016-09-01

    Evolution of chemical states and defect structure in titanium during low energy nitrogen ion implantation by Plasma Immersion Ion Implantation (PIII) process is studied. The underlying process of chemical state evolution is investigated using secondary ion mass spectrometry and X-ray photoelectron spectroscopy. The implantation induced defect structure evolution as a function of dose is elucidated using variable energy positron annihilation Doppler broadening spectroscopy (PAS) and the results were corroborated with chemical state. Formation of 3 layers of defect state was modeled to fit PAS results.

  17. Temperature effects on chemical structure and motion in coal. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Maciel, G.E.

    1996-09-30

    The objective of this project was to apply recently developed, state-of-the-art nuclear magnetic resonance (NMR) techniques to examine in situ changes in the chemical structure and molecular/macromolecular motion in coal as the temperature is increased above room temperature. Although alterations in the chemical structure of coal have been studied previously by {sup 13}C NMR, using quenched samples, the goal of this project was to examine these chemical structural changes, and changes in molecular/macromolecular mobility that may precede or accompany the chemical changes, at elevated temperatures, using modern {sup 13}C and {sup 1}H NMR techniques, especially {sup 1}H dipolar-dephasing techniques and related experiments pioneered in the laboratory for examining pyridine-saturated coals. This project consisted of the following four primary segments and related efforts on matters relevant to the first four tasks. (1) {sup 1}H NMR characterization of coal structure and mobility as a function of temperature variation over a temperature range (30--240 C) for which substantial chemical transformations were not anticipated. (2) {sup 1}H NMR characterization of coal structure, mobility and conversion as a function of temperature variation over a temperature range (240--500 C) for which chemical transformations of coal are known to occur. (3) {sup 13}C NMR investigation of coal structure/mobility as a function of temperature over a temperature range (30--240 C) for which substantial chemical transformations were not anticipated. (4) {sup 13}C NMR investigation of coal structure, dynamics and conversion as a function of temperature variation over a range (240--500 C) for which chemical transformations of coal are known to occur. (5) Related matters relevant to the first four tasks: (a) {sup 1}H CRAMPS NMR characterization of oil shales and their kerogen concentrates; and (b) improved quantitation in {sup 13}C MAS characterization of coals.

  18. Brazilian kefir: structure, microbial communities and chemical composition

    Directory of Open Access Journals (Sweden)

    Karina Teixeira Magalhães

    2011-06-01

    Full Text Available Microbial ecology and chemical composition of Brazilian kefir beverage was performed. The microorganisms associated with Brazilian kefir were investigated using a combination of phenotypic and genotypic methods. A total of 359 microbial isolates were identified. Lactic acid bacteria (60.5% were the major isolated group identified, followed by yeasts (30.6% and acetic acid bacteria (8.9%. Lactobacillus paracasei (89 isolates, Lactobacillus parabuchneri (41 isolates, Lactobacillus casei (32 isolates, Lactobacillus kefiri (31 isolates, Lactococcus lactis (24 isolates, Acetobacter lovaniensis (32 isolates, Kluyveromyces lactis (31 isolates, Kazachstania aerobia (23 isolates, Saccharomyces cerevisiae (41 isolates and Lachancea meyersii (15 isolates were the microbial species isolated. Scanning electron microscopy showed that the microbiota was dominated by bacilli (short and curved long cells growing in close association with lemon-shaped yeasts cells. During the 24 h of fermentation, the protein content increased, while lactose and fat content decreased. The concentration of lactic acid ranged from 1.4 to 17.4 mg/ml, and that of acetic acid increased from 2.1 to 2.73 mg/ml. The production of ethanol was limited, reaching a final mean value of 0.5 mg/ml.

  19. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  20. Analysis of composite structural elements

    Directory of Open Access Journals (Sweden)

    A. Baier

    2010-12-01

    Full Text Available Purpose: The themes of the study are composite structural components. For this purpose have been designed and built several research positions.Design/methodology/approach: Using different structural materials to build new device components requires multiple tests of the components. Research posts were designed in the advanced graphical program CAx Siemens NX 7.5. Analysed samples were made from the glass fibre, aramid and carbon of various weights. Due to the specific use of composite materials it focuses on the elements in the form of plates and flat bars. For the examination of experimental strain gauge technique was used bead, the force sensor and displacement sensor. The experimental methods were compared with computer simulation using the FEM.Findings: The aim of this study was to determine the basic material constants and a comparison of the experimental method and the method of computer simulation.Research limitations/implications: Change the number of layers and how to connect the laminate with the steel plate changes mechanical properties of the structural component.Practical implications: The ultimate result will be knowledge on the different forms of laminates, such as material properties, the stresses in all layers, strain and comparing the results obtained by two methods.Originality/value: The expected outcome of the study will be the composition and method of joining composite laminate with a steel plate to the possible application in the repair and construction of structural elements of freight wagons.

  1. An ab initio quantum chemical investigation of the structure and stability of ozone-water complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pradeep [Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Sathyamurthy, N., E-mail: nsath@iitk.ac.in [Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli 140306 (India)

    2013-03-29

    Highlights: ► Eclipse geometry most stable for the 1:1 ozone-water complex. ► Cyclic structure most stable for the 1:2 complex. ► Shift in the vertical electronic excitation energy of ozone due to hydration. - Abstract: Ab initio quantum chemical calculations have been carried out to investigate the structure and stability of 1:1 and 1:2 ozone-water complexes. All the geometries have been optimized at the CCSD level of theory using aug-cc-pVDZ and aug-cc-pVTZ basis sets. The importance of correlation-consistent basis sets in deciding the nature of critical points on these complexes is emphasized. An analysis based on the dipole moment of the complexes and the charge distribution on atoms follows. The effect of ozone molecule on the structure and properties of water dimer is also investigated. Values of the vertical electronic excitation energy and the corresponding transition dipole moment have been calculated for the ozone-water complexes using the multi-reference-configuration-interaction method and the aug-cc-pVTZ basis set. The calculated shift in vibrational frequencies due to complex formation is compared with the earlier reported experimental and theoretical values.

  2. Effect of chemical fertilization and green manure on the abundance and community structure of ammonia oxidizers in a paddy soil

    Directory of Open Access Journals (Sweden)

    Yu Fang

    2015-12-01

    Full Text Available Ammonia oxidization is a critical step in the soil N cycle and can be affected by the fertilization regimes. Chinese milk-vetch (Astragalus sinicus L., MV is a major green manure of rice (Oryza sativa L. fields in southern China, which is recommended as an important agronomic practice to improve soil fertility. Soil chemical properties, abundance and community structures of ammonia-oxidizing bacteria (AOB and ammonia-oxidizing archaea (AOA in a MV-rice rotation field under different fertilization regimes were investigated. The field experiment included six treatments: control, without MV and chemical fertilizer (CK; 100% chemical fertilizer (NPK; 18 000 kg MV ha-1 plus 100% chemical fertilizer (NPKM1; 18 000 kg MV ha-1 plus 40% chemical fertilizer (NPKM2; 18 000 kg MV ha-1 alone (MV; and 18 000 kg MV ha-1 plus 40% chemical fertilizer plus straw (NPKMS. Results showed that NPKMS treatment could improve the soil fertility greatly although the application of 60% chemical fertilizer. The abundance of AOB only in the MV treatment had significant difference with the control; AOA were more abundant than AOB in all corresponding treatments. The NPKMS treatment had the highest AOA abundance (1.19 x 10(8 amoA gene copies g-1 and the lowest abundance was recorded in the CK treatment (3.21 x 10(7 amoA gene copies g-1. The abundance of AOA was significantly positively related to total N, available N, NH4+-N, and NO3--N. The community structure of AOA exhibited little variation among different fertilization regimes, whereas the community structure of AOB was highly responsive. Phylogenetic analysis showed that all AOB sequences were affiliated with Nitrosospira or Nitrosomonas and all AOA denaturing gradient gel electrophoresis (DGGE bands belonged to the soil and sediment lineage. These findings could be fundamental to improve our understanding of AOB and AOA in the N cycle in the paddy soil.

  3. At the brink of supercoloniality: genetic, behavioral and chemical assessments of population structure of the desert ant Cataglyphis niger

    Directory of Open Access Journals (Sweden)

    Maya eSaar

    2014-05-01

    Full Text Available The nesting habits of ants play an important role in structuring ant populations. They vary from monodomy, a colony occupies a single nest, via polydomy, a colony occupies multiple adjacent nests, to supercoloniality, a colony spans over large territories comprising dozen to thousands nests without having any boundaries. The population structure of the desert ant Cataglyphis niger, previously considered to form supercolonies, was studied using genetic, chemical and behavioral tools in plots of 50x50 meters at two distinct populations. At the Palmahim site, the plot comprised 15 nests that according to the genetic analysis constituted three colonies. Likewise at the Rishon Leziyyon site 14 nests constituted 5 genetic colonies. In both sites, both chemical analysis and the behavioral (aggression tests confirmed the colony genetic architecture. The behavioral tests also revealed that aggression between colonies within a population was higher than that exhibited between colonies of different populations, suggesting the occurrence of the nasty neighbor phenomenon. In contrast to supercolony structure previously reported in another population of this species, the presently studied populations were composed of polydomous colonies. However, both the genetic and chemical data revealed that the inter-colonial differences between sites were larger than those within site, suggesting some within-site population viscosity. Thus, C. niger exhibits flexible nesting characteristics, from polydomy to supercoloniality, and can be considered at the brink of supercoloniality. We attribute the differences in population structure among sites to the intensity of intraspecific competition.

  4. Structural Change of Wood Molecules and Chemorheological Behaviors during Chemical Treatment

    Institute of Scientific and Technical Information of China (English)

    Xie Manhua; Zhao Guangjie

    2004-01-01

    It is very important to clarify the relationship of changes of molecular combinations in wood cell walls and the chemical rheological behavior during various chemical reagent treatments, for it would be helpful to develop new wood modification technologies and to enrich the theory of chemical rheology of wood. Based on previous investigations on the chemorheological properties of wood by chemical treatments and the applied methods in chemical rheology of wool fibers, this paper proposes the study of various additional reagents to wood saturated in water for long periods of time in order to investigate the chemical rheology of wood, which can provide information about the character of combinations between wood molecules and the structural changes of molecules and further put forward the idea of modifying wood in a decrystallized state.

  5. Robustness Analysis of Timber Truss Structure

    DEFF Research Database (Denmark)

    Rajčić, Vlatka; Čizmar, Dean; Kirkegaard, Poul Henning;

    2010-01-01

    The present paper discusses robustness of structures in general and the robustness requirements given in the codes. Robustness of timber structures is also an issues as this is closely related to Working group 3 (Robustness of systems) of the COST E55 project. Finally, an example of a robustness...... evaluation of a widespan timber truss structure is presented. This structure was built few years ago near Zagreb and has a span of 45m. Reliability analysis of the main members and the system is conducted and based on this a robustness analysis is preformed....

  6. Local Structures and Chemical Properties of Deprotonated Arginine

    Institute of Scientific and Technical Information of China (English)

    Hong-bao Li; Zi-jing Lin; Yi Luo

    2012-01-01

    The potential energy surface of gaseous deprotonated arginine has been systematically investigated by first principles calculations.At the B3LYP/6-31G(d) level,apart from the identification of several stable local structures,a new global minimum is located which is about 6.56 kJ/mol more stable than what has been reported.The deprotonated arginine molecule has two distinct forms with the deprotonation at the carboxylate group (COO-).These two forms are bridged by a very high energy barrier and possess very different IR spectral profiles.Our calculated proton dissociation energy and gas-phase acidity of arginine molecule are found to be in good agreement with the corresponding experimental results.The predicted geometries,dipole moments,rotational constants,vertical ionization energies and IR spectra of low energy conformers will be useful for future experimental measurements.

  7. Chemical bonding and electronic structure of fullerene-based compounds

    International Nuclear Information System (INIS)

    This talk will focus on the nature of bonding of fullerenes with other materials as demonstrated by synchrotron radiation and x-ray photoemission. Adsorption of C60 on metallic and semiconducting substrates occurs via charge transfer from the substrate to a LUMO-derived resonance, resulting in Fermi level alignment and dipole formation. Bonding of metal atoms to C60 depends on the metal work function and bulk cohesive energy. Evaporation of high cohesive energy materials onto a fullerene substrate results in metal cluster nucleation and limited C60 disruption for transition metals. Low cohesive energy metals form compounds with a degree of ionic character related to the metal work function. Photoemission results show the formation of ionic K-fulleride compounds while greater hybridization is observed for Ca-rich fullerides. Finally the electronic structure of fluorinated and hydrogenated fullerenes demonstrate changes in states derived from C60 π bonds due to reaction of dangling bonds

  8. Chemical analysis of outgassing contaminants on spacecraft surfaces

    Science.gov (United States)

    Mcnutt, R. C.

    1973-01-01

    Methods for analyzing and characterizing outgassing contaminants from such materials as RTV 501 potting compound and S 13 G paint are presented. Fractional distillation of a gross distillate from RTV 501 rubber was carried out and the distilled fractions examined as to their ultraviolet and infrared spectra by gas liquid chromatography. A sensitive technique for structural analysis and molecular identification was found to consist of a gas chromatography-mass spectroscopy system, which was determined to be economically unfeasible at present.

  9. Analysis of changes in the chemical composition of the blast furnace coke at high temperatures

    Directory of Open Access Journals (Sweden)

    A. Konstanciak

    2012-12-01

    Full Text Available Purpose: The main purpose of this paper was to analyze the behavior of coke in the blast furnace. The analysis of changes in chemical composition of coke due to impact of inert gas and air at different temperatures was made. The impact of the application of the thermoabrasion coefficient on the porosity of coke was also analyzed.Design/methodology/approach: By applying the Computer Thermochemical Database of the TERMO system (REAKTOR1 and REAKTOR3 three groups of substances can be distinguished. The chemical composition of blast furnace coke and the results of calculations of changes of chemical composition of coke heat treated under certain conditions were compared. The structural studies of these materials were presented.Findings: The results of the analysis of ash produced from one of Polish cokes was taken for consideration. This is not the average composition of Polish coke ashes, nevertheless it is representative of most commonly occurring chemical compositions.Practical implications: Thanks to the thermochemical calculations it is possible to predict ash composition after the treatment in a blast furnace. Those information was crucial and had an actual impact on determining the coke quality.Originality/value: Presentation of the analytical methods which, according to author, can be very useful to evaluate and identify the heat treatment for blast furnaces cokes. The research pursued represents part of a larger project carried out within the framework of Department Extraction and Recycling of Metals, Czestochowa University of Technology.

  10. NAPS: Network Analysis of Protein Structures.

    Science.gov (United States)

    Chakrabarty, Broto; Parekh, Nita

    2016-07-01

    Traditionally, protein structures have been analysed by the secondary structure architecture and fold arrangement. An alternative approach that has shown promise is modelling proteins as a network of non-covalent interactions between amino acid residues. The network representation of proteins provide a systems approach to topological analysis of complex three-dimensional structures irrespective of secondary structure and fold type and provide insights into structure-function relationship. We have developed a web server for network based analysis of protein structures, NAPS, that facilitates quantitative and qualitative (visual) analysis of residue-residue interactions in: single chains, protein complex, modelled protein structures and trajectories (e.g. from molecular dynamics simulations). The user can specify atom type for network construction, distance range (in Å) and minimal amino acid separation along the sequence. NAPS provides users selection of node(s) and its neighbourhood based on centrality measures, physicochemical properties of amino acids or cluster of well-connected residues (k-cliques) for further analysis. Visual analysis of interacting domains and protein chains, and shortest path lengths between pair of residues are additional features that aid in functional analysis. NAPS support various analyses and visualization views for identifying functional residues, provide insight into mechanisms of protein folding, domain-domain and protein-protein interactions for understanding communication within and between proteins. URL:http://bioinf.iiit.ac.in/NAPS/. PMID:27151201

  11. Modal structure of chemical mass size distribution in the high Arctic aerosol

    Science.gov (United States)

    Hillamo, Risto; Kerminen, Veli-Matti; Aurela, Minna; MäKelä, Timo; Maenhaut, Willy; Leek, Caroline

    2001-11-01

    Chemical mass size distributions of aerosol particles were measured in the remote marine boundary layer over the central Arctic Ocean as part of the Atmospheric Research Program on the Arctic Ocean Expedition 1996 (AOE-96). An inertial impaction method was used to classify aerosol particles into different size classes for subsequent chemical analysis. The particle chemical composition was determined by ion chromatography and by the particle-induced X-ray emission technique. Continuous particle size spectra were extracted from the raw data using a data inversion method. Clear and varying modal structures for aerosols consisting of primary sea-salt particles or of secondary particles related to dimethyl sulfide emissions were found. Concentration levels of all modes decreased rapidly when the distance from open sea increased. In the submicrometer size range the major ions found by ion chromatography were sulfate, methane sulfonate, and ammonium. They had most of the time a clear Aitken mode and one or two accumulation modes, with aerodynamic mass median diameters around 0.1 μm, 0.3 μm, and between 0.5-1.0 μm, respectively. The overall submicron size distributions of these three ions were quite similar, suggesting that they were internally mixed over most of this size range. The corresponding modal structure was consistent with the mass size distributions derived from the particle number size distributions measured with a differential mobility particle sizer. The Aitken to accumulation mode mass ratio for nss-sulfate and MSA was substantially higher during clear skies than during cloudy periods. Primary sea-salt particles formed a mode with an aerodynamic mass median diameter around 2 μm. In general, the resulting continuous mass size distributions displayed a clear modal structure consistent with our understanding of the two known major source mechanisms. One is the sea-salt aerosol emerging from seawater by bubble bursting. The other is related to

  12. Valence XPS structure and chemical bond in Cs2UO2Cl4

    Directory of Open Access Journals (Sweden)

    Teterin Yury A.

    2016-01-01

    Full Text Available Quantitative analysis was done of the valence electrons X-ray photoelectron spectra structure in the binding energy (BE range of 0 eV to ~35 eV for crystalline dicaesium tetrachloro-dioxouranium (VI (Cs2UO2Cl4. This compound contains the uranyl group UO2. The BE and structure of the core electronic shells (~35 eV-1250 eV, as well as the relativistic discrete variation calculation results for the UO2Cl4(D4h cluster reflecting U close environment in Cs2UO2Cl4 were taken into account. The experimental data show that many-body effects due to the presence of cesium and chlorine contribute to the outer valence (0-~15 eV BE spectral structure much less than to the inner valence (~15 eV-~35 eV BE one. The filled U5f electronic states were theoretically calculated and experimentally confirmed to be present in the valence band of Cs2UO2Cl4. It corroborates the suggestion on the direct participation of the U5f electrons in the chemical bond. Electrons of the U6p atomic orbitals participate in formation of both the inner (IVMO and the outer (OVMO valence molecular orbitals (bands. The filled U6p and the O2s, Cl3s electronic shells were found to make the largest contributions to the IVMO formation. The molecular orbitals composition and the sequence order in the binding energy range 0 eV-~35 eV in the UO2Cl4 cluster were established. The experimental and theoretical data allowed a quantitative molecular orbitals scheme for the UO2Cl4 cluster in the BE range 0-~35 eV, which is fundamental for both understanding the chemical bond nature in Cs2UO2Cl4 and the interpretation of other X-ray spectra of Cs2UO2Cl4. The contributions to the chemical binding for the UO2Cl4 cluster were evaluated to be: the OVMO contribution - 76%, and the IVMO contribution - 24 %.

  13. ANALYSIS OF THERMAL-CHEMICAL CHARACTERISTICS OF BIOMASS ENERGY PELLETS

    Directory of Open Access Journals (Sweden)

    Zorica Gluvakov

    2014-09-01

    Full Text Available In modern life conditions, when emphasis is on environmental protection and sustainable development, fuels produced from biomass are increasingly gaining in importance, and it is necessary to consider the quality of end products obtained from biomass. Based on the existing European standards, collected literature and existing laboratory methods, this paper presents results of testing individual thermal - chemical properties of biomass energy pellets after extrusion and cooling the compressed material. Analysing samples based on standard methods, data were obtained on the basis of which individual thermal-chemical properties of pellets were estimated. Comparing the obtained results with the standards and literature sources, it can be said that moisture content, ash content and calorific values are the most important parameters for quality analysis which decide on applicability and use-value of biomass energy pellets, as biofuel. This paper also shows the impact of biofuels on the quality of environmental protection. The conclusion provides a clear statement of quality of biomass energy pellets.

  14. Filamentary structure in chemical tracer distributions near the subtropical jet following a wave breaking event

    Directory of Open Access Journals (Sweden)

    J. Ungermann

    2013-10-01

    Full Text Available This paper presents a set of observations and analyses of trace gas cross sections in the extratropical upper troposphere/lower stratosphere (UTLS. The spatially highly resolved (≈0.5 km vertically and 12.5 km horizontally cross sections of ozone (O3, nitric acid (HNO3, and peroxyacetyl nitrate (PAN, retrieved from the measurements of the CRISTA-NF infrared limb sounder flown on the Russian M55-Geophysica, revealed intricate layer structures in the region of the subtropical tropopause break. The chemical structure in this region shows an intertwined stratosphere and troposphere. The observed filaments in all discussed trace gases are of a spatial scale of less than 0.8 km vertically and about 200 km horizontally across the jet stream. Backward trajectory calculations confirm that the observed filaments are the result of a breaking Rossby wave in the preceding days. An analysis of the trace gas relationships between PAN and O3 identifies four distinct groups of air mass: polluted subtropical tropospheric air, clean tropical upper-tropospheric air, the lowermost stratospheric air, and air from the deep stratosphere. The tracer relationships further allow the identification of tropospheric, stratospheric, and the transitional air mass made of a mixture of UT and LS air. Mapping of these air mass types onto the geo-spatial location in the cross sections reveals a highly structured extratropical transition layer (ExTL. Finally, the ratio between the measured reactive nitrogen species (HNO3 + PAN + ClONO2 and O3 is analysed to estimate the influence of tropospheric pollution on the extratropical UTLS. In combination, these diagnostics provide the first example of a multi-species two-dimensional picture of the inhomogeneous distribution of chemical species within the UTLS region. Since Rossby wave breaking occurs frequently in the region of the tropopause break, these observed fine-scale filaments are likely ubiquitous in the region. The

  15. Materials ``alchemy'': Shape-preserving chemical transformation of micro-to-macroscopic 3-D structures

    Science.gov (United States)

    Sandhage, Kenneth H.

    2010-06-01

    The scalable fabrication of nano-structured materials with complex morphologies and tailorable chemistries remains a significant challenge. One strategy for such synthesis consists of the generation of a solid structure with a desired morphology (a “preform”), followed by reactive conversion of the preform into a new chemistry. Several gas/solid and liquid/solid reaction processes that are capable of such chemical conversion into new micro-to-nano-structured materials, while preserving the macroscopic-to-microscopic preform morphologies, are described in this overview. Such shape-preserving chemical transformation of one material into another could be considered a modern type of materials “alchemy.”

  16. Chemical gas analyzers for proximate analysis of mine atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Pochenkova, T.K.; Klassovskaya, N.A.; Zlenko, A.G.; Gus' kova, A.N. (Vsesoyuznyi Nauchno-Issledovatel' skii Institut Gornogo Dela, Donetsk (Ukraine))

    1992-09-01

    Describes a series of chemical gas analyzers developed by the VNIIGD institute for proximate analysis of mine atmosphere in coal mines. The new GKh-4, GKh-5, GKh-6, GKh CO-5 use detector tubes for carbon monoxide and dioxide, nitrogen oxides, sulfur dioxide, oxygen and hydrogen sulfide. These devices allow miners to determine gas concentrations in the mine atmosphere in less than 4 minutes with an accuracy of +/-25%. The series is now complemented by the GKh-M CH[sub 2]O-0.004 gas analyzer for measuring formaldehyde content in mine air during mine rescue operations conducted with the use of carbamide-formaldehyde resins. Key technical data on the gas analyzers are given.

  17. Chemical analysis of ancient relicts in the Milky Way disk

    Directory of Open Access Journals (Sweden)

    Tautvaišienė G.

    2012-02-01

    Full Text Available We present detailed analysis of two groups of F- and G- type stars originally found to have similarities in their orbital parameters. The distinct kinematic properties suggest that they might originate from ancient accretion events in the Milky Way. From high resolution spectra taken with the spectrograph FIES at the Nordic Optical Telescope, La Palma, we determined abundances of oxygen, alpha- and r-process elements. Our results indicate that the sample of investigated stars is chemically homogeneous and the abundances of oxygen, alpha and r-process elements are overabundant in comparison with Galactic disk dwarfs. This provides the additional evidence that those stellar groups had the common formation and possible origin from disrupted satellites.

  18. The relationship between chemical structure and dielectric properties of plasma-enhanced chemical vapor deposited polymer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Hao [Materials Sci and Tech Applications, LLC, 409 Maple Springs Drive, Dayton OH 45458 (United States)]. E-mail: hao.jiang@wpafb.af.mil; Hong Lianggou [Materials Sci and Tech Applications, LLC, 409 Maple Springs Drive, Dayton OH 45458 (United States); Venkatasubramanian, N. [Research Institute, University of Dayton, 300 College Park, Dayton, OH 45469-0168 (United States); Grant, John T. [Research Institute, University of Dayton, 300 College Park, Dayton, OH 45469-0168 (United States); Eyink, Kurt [Air Force Research Laboratory, Materials Directorate, 3005 Hobson Way, Wright-Patterson Air Force Base, OH 45433-7707 (United States); Wiacek, Kevin [Air Force Research Laboratory, Propulsion Directorate, 1950 Fifth Street, Wright-Patterson Air Force Base, OH 45433-7251 (United States); Fries-Carr, Sandra [Air Force Research Laboratory, Propulsion Directorate, 1950 Fifth Street, Wright-Patterson Air Force Base, OH 45433-7251 (United States); Enlow, Jesse [Air Force Research Laboratory, Materials Directorate, 3005 Hobson Way, Wright-Patterson Air Force Base, OH 45433-7707 (United States); Bunning, Timothy J. [Air Force Research Laboratory, Materials Directorate, 3005 Hobson Way, Wright-Patterson Air Force Base, OH 45433-7707 (United States)

    2007-02-26

    Polymer dielectric films fabricated by plasma enhanced chemical vapor deposition (PECVD) have unique properties due to their dense crosslinked bulk structure. These spatially uniform films exhibit good adhesion to a variety of substrates, excellent chemical inertness, high thermal resistance, and are formed from an inexpensive, solvent-free, room temperature process. In this work, we studied the dielectric properties of plasma polymerized (PP) carbon-based polymer thin films prepared from two precursors, benzene and octafluorocyclobutane. Two different monomer feed locations, directly in the plasma zone or in the downstream region (DS) and two different pressures, 80 Pa (high pressure) or 6.7 Pa (low pressure), were used. The chemical structure of the PECVD films was examined by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The dielectric constant ({epsilon} {sub r}) and dielectric loss (tan {delta}) of the films were investigated over a range of frequencies up to 1 MHz and the dielectric strength (breakdown voltage) (F {sub b}) was characterized by the current-voltage method. Spectroscopic ellipsometry was performed to determine the film thickness and refractive index. Good dielectric properties were exhibited, as PP-benzene films formed in the high pressure, DS region showed a F{sub b} of 610 V/{mu}m, an {epsilon} {sub r} of 3.07, and a tan {delta} of 7.0 x 10{sup -3} at 1 kHz. The PECVD processing pressure has a significant effect on final film structure and the film's physical density has a strong impact on dielectric breakdown strength. Also noted was that the residual oxygen content in the PP-benzene films significantly affected the frequency dependences of the dielectric constant and loss.

  19. Comparison of descriptive sensory analysis and chemical analysis for oxidative changes in milk

    DEFF Research Database (Denmark)

    Hedegaard, R V; Kristensen, D; Nielsen, Jacob Holm;

    2006-01-01

    and lipolytic changes occurring in the milk during chill storage for 4 d. Sensory analysis and chemical analysis showed high correlation between the typical descriptors for oxidation such as cardboard, metallic taste, and boiled milk and specific chemical markers for oxidation such as hexanal. Notably, primary......Oxidation in 3 types of bovine milk with different fatty acid profiles obtained through manipulation of feed was evaluated by analytical methods quantifying the content of potential antioxidants, the tendency of formation of free radicals, and the accumulation of primary and secondary oxidation...

  20. Structural and stability investigation of the anticancer drug Cyclophosphamide via quantum chemical calculations :A nanotube drug delivery

    Directory of Open Access Journals (Sweden)

    Z. Felegari

    2014-12-01

    Full Text Available Cyclophosphamide is a medicine used to interfere with the growth and spread of tumor cells and treat cancers and autoimmune disorders.This work reports the study of anticancer drugs with density functional theory (DFT and electronic structures.Its structure was optimized with B3LYP/6-311G* level in the gas phase and different solvents (SCRF calculation. NBO analysis,NMR parameter,thermodynamic properties,HOMO and LUMO,HOMO-LUMO band gap, and the electronic chemical potential (µ were calculated. The results indicated that the Cyclophosphamide in water solvent is more stable than the gas phase orother solvents.

  1. Structural Dynamics and Data Analysis

    Science.gov (United States)

    Luthman, Briana L.

    2013-01-01

    This project consists of two parts, the first will be the post-flight analysis of data from a Delta IV launch vehicle, and the second will be a Finite Element Analysis of a CubeSat. Shock and vibration data was collected on WGS-5 (Wideband Global SATCOM- 5) which was launched on a Delta IV launch vehicle. Using CAM (CAlculation with Matrices) software, the data is to be plotted into Time History, Shock Response Spectrum, and SPL (Sound Pressure Level) curves. In this format the data is to be reviewed and compared to flight instrumentation data from previous flights of the same launch vehicle. This is done to ensure the current mission environments, such as shock, random vibration, and acoustics, are not out of family with existing flight experience. In family means the peaks on the SRS curve for WGS-5 are similar to the peaks from the previous flights and there are no major outliers. The curves from the data will then be compiled into a useful format so that is can be peer reviewed then presented before an engineering review board if required. Also, the reviewed data will be uploaded to the Engineering Review Board Information System (ERBIS) to archive. The second part of this project is conducting Finite Element Analysis of a CubeSat. In 2010, Merritt Island High School partnered with NASA to design, build and launch a CubeSat. The team is now called StangSat in honor of their mascot, the mustang. Over the past few years, the StangSat team has built a satellite and has now been manifested for flight on a SpaceX Falcon 9 launch in 2014. To prepare for the final launch, a test flight was conducted in Mojave, California. StangSat was launched on a Prospector 18D, a high altitude rocket made by Garvey Spacecraft Corporation, along with their sister satellite CP9 built by California Polytechnic University. However, StangSat was damaged during an off nominal landing and this project will give beneficial insights into what loads the CubeSat experienced during the crash

  2. Dynamic analysis and design of offshore structures

    CERN Document Server

    Chandrasekaran, Srinivasan

    2015-01-01

    This book  attempts to provide readers with an overall idea of various types of offshore platform geometries. It covers the various environmental loads encountered by these structures, a detailed description of the fundamentals of structural dynamics in a class-room style, estimate of damping in offshore structures and their applications in the preliminary analysis and design. Basic concepts of structural dynamics are emphasized through simple illustrative examples and exercises. Design methodologies and guidelines, which are FORM based concepts are explained through a few applied example structures. Each chapter also has tutorials and exercises for self-learning. A dedicated chapter on stochastic dynamics will help the students to extend the basic concepts of structural dynamics to this advanced domain of research. Hydrodynamic response of offshore structures with perforated members is one of the recent research applications, which is found to be one of the effective manner of retrofitting offshore structur...

  3. Extended Functional Groups (EFG: An Efficient Set for Chemical Characterization and Structure-Activity Relationship Studies of Chemical Compounds

    Directory of Open Access Journals (Sweden)

    Elena S. Salmina

    2015-12-01

    Full Text Available The article describes a classification system termed “extended functional groups” (EFG, which are an extension of a set previously used by the CheckMol software, that covers in addition heterocyclic compound classes and periodic table groups. The functional groups are defined as SMARTS patterns and are available as part of the ToxAlerts tool (http://ochem.eu/alerts of the On-line CHEmical database and Modeling (OCHEM environment platform. The article describes the motivation and the main ideas behind this extension and demonstrates that EFG can be efficiently used to develop and interpret structure-activity relationship models.

  4. Structure of Marketing Planning: A Reflective Analysis

    OpenAIRE

    Luciano Augusto Toledo; Adriana Beatriz Madeira; Guilherme Farias Shiraishi; Marcos Garber

    2014-01-01

    This study aims to promote a reflective analysis about the action planning structure in the marketing context. The work was structured in the form of essay and presents the theoretical aspects about the Marketing Planning. The intention of the article is to provide critical insights into the needs of planning marketing activities. For this purpose the document is organized as of an introduction that contextualizes the subject, accompanied by a critical analysis. Finally, the final considerati...

  5. Analysis model of structure-HDS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Presents the model established for Structure-HDS(hydraulic damper system) analysis on the basis of the theoretical analysis model of non-compressed fluid in the round pipe will an uniform velocity used as the basic variable, and pressure losses resulting from cross section changes of fluid route taken into consideration. Which provides necessary basis for researches on earthquake responses of a structure with a spacious first story, equipped with HDS at first floor.

  6. Microarray Technology for Major Chemical Contaminants Analysis in Food: Current Status and Prospects

    Directory of Open Access Journals (Sweden)

    Xiaoxia Ding

    2012-07-01

    Full Text Available Chemical contaminants in food have caused serious health issues in both humans and animals. Microarray technology is an advanced technique suitable for the analysis of chemical contaminates. In particular, immuno-microarray approach is one of the most promising methods for chemical contaminants analysis. The use of microarrays for the analysis of chemical contaminants is the subject of this review. Fabrication strategies and detection methods for chemical contaminants are discussed in detail. Application to the analysis of mycotoxins, biotoxins, pesticide residues, and pharmaceutical residues is also described. Finally, future challenges and opportunities are discussed.

  7. Polysaccharides from Arctium lappa L.: Chemical structure and biological activity.

    Science.gov (United States)

    Carlotto, Juliane; de Souza, Lauro M; Baggio, Cristiane H; Werner, Maria Fernanda de P; Maria-Ferreira, Daniele; Sassaki, Guilherme L; Iacomini, Marcello; Cipriani, Thales R

    2016-10-01

    The plant Arctium lappa L. is popularly used to relieve symptoms of inflammatory disorders. A crude polysaccharide fraction (SAA) resulting of aqueous extraction of A. lappa leaves showed a dose dependent anti-edematogenic activity on carrageenan-induced paw edema, which persisted for up to 48h. Sequential fractionation by ultrafiltration at 50kDa and 30kDa cut-off membranes yielded three fractions, namely RF50, RF30, and EF30. All these maintained the anti-edematogenic effect, but RF30 showed a more potent action, inhibiting 57% of the paw edema at a dose of 4.9mg/kg. The polysaccharide RF30 contained galacturonic acid, galactose, arabinose, rhamnose, glucose, and mannose in a 7:4:2:1:2:1 ratio and had a Mw of 91,000g/mol. Methylation analysis and NMR spectroscopy indicated that RF30 is mainly constituted by a type I rhamnogalacturonan branched by side chains of types I and II arabinogalactans, and arabinan.

  8. Polysaccharides from Arctium lappa L.: Chemical structure and biological activity.

    Science.gov (United States)

    Carlotto, Juliane; de Souza, Lauro M; Baggio, Cristiane H; Werner, Maria Fernanda de P; Maria-Ferreira, Daniele; Sassaki, Guilherme L; Iacomini, Marcello; Cipriani, Thales R

    2016-10-01

    The plant Arctium lappa L. is popularly used to relieve symptoms of inflammatory disorders. A crude polysaccharide fraction (SAA) resulting of aqueous extraction of A. lappa leaves showed a dose dependent anti-edematogenic activity on carrageenan-induced paw edema, which persisted for up to 48h. Sequential fractionation by ultrafiltration at 50kDa and 30kDa cut-off membranes yielded three fractions, namely RF50, RF30, and EF30. All these maintained the anti-edematogenic effect, but RF30 showed a more potent action, inhibiting 57% of the paw edema at a dose of 4.9mg/kg. The polysaccharide RF30 contained galacturonic acid, galactose, arabinose, rhamnose, glucose, and mannose in a 7:4:2:1:2:1 ratio and had a Mw of 91,000g/mol. Methylation analysis and NMR spectroscopy indicated that RF30 is mainly constituted by a type I rhamnogalacturonan branched by side chains of types I and II arabinogalactans, and arabinan. PMID:27311502

  9. Structural features in TAR RNA of human and simian immunodeficiency viruses: a phylogenetic analysis.

    OpenAIRE

    Berkhout, B.

    1992-01-01

    A comparative analysis of TAR RNA structures in human and simian immunodeficiency viruses reveals the conservation of certain structural features despite the divergence in sequence. Both the TAR elements of HIV-1 and SIV-chimpanzee can be folded into relatively simple one-stem hairpin structures. Chemical and RNAase probes were used to analyze the more complex structure of HIV-2 TAR RNA, which folds into a branched hairpin structure. A surprisingly similar RNA conformation can be proposed for...

  10. Structural analysis of impeller for SMART MCP

    International Nuclear Information System (INIS)

    The structural integrity of the MCP impeller is important for the safe and reliable operation of the SMART, since the impeller is operated for long period inside the reactor under high pressure and high temperature. In this study, an analysis model to evaluate the structural integrity of axial pump impeller has been developed and the stress state in the impeller of SMART MCP has been calculated for the applied centrifugal and hydraulic forces. The structural integrity of the impeller has been demonstrated by comparing the analysis results with the allowable stresses. The modal analysis of the impeller has been also performed to investigate the possibility of the resonances of the impeller blades with the rotational frequencies. As a means to reduce the time required for the analysis, a cyclic symmetric analysis model with optimum boundary conditions is proposed by comparing the results from full model analyses

  11. Computational structural analysis and finite element methods

    CERN Document Server

    Kaveh, A

    2014-01-01

    Graph theory gained initial prominence in science and engineering through its strong links with matrix algebra and computer science. Moreover, the structure of the mathematics is well suited to that of engineering problems in analysis and design. The methods of analysis in this book employ matrix algebra, graph theory and meta-heuristic algorithms, which are ideally suited for modern computational mechanics. Efficient methods are presented that lead to highly sparse and banded structural matrices. The main features of the book include: application of graph theory for efficient analysis; extension of the force method to finite element analysis; application of meta-heuristic algorithms to ordering and decomposition (sparse matrix technology); efficient use of symmetry and regularity in the force method; and simultaneous analysis and design of structures.

  12. Entity Authentication:Analysis using Structured Intuition

    DEFF Research Database (Denmark)

    Ahmed, Naveed; Jensen, Christian D.

    2010-01-01

    In this paper, we propose a new method for the analysis that uses intuition of the analyst in a structured way. First we define entity authentication in terms of fine level authentication goals (FLAGs). Then we use some relevant structures in protocol narrations and use them to justify FLAGs for...

  13. Group theory analysis of braided geometry structures

    Institute of Scientific and Technical Information of China (English)

    FENG Wei; MA Wensuo

    2005-01-01

    The braided geometry structures are analyzed with point groups and space groups for which the continuous yarn of the braided preforms is segmented and expressed in some special symbols. All structures of braided material are described and classified with group theory, and new braiding methods are found. The group theory analysis lays the theoretical foundation for optimizing material performance.

  14. Using rhetorical structure in sentiment analysis

    NARCIS (Netherlands)

    Hogenboom, Alexander; Frasincar, Flavius; Jong, de Franciska; Kaymak, Uzay

    2015-01-01

    Automated sentiment analysis has become an active field of study with a broad applicability. One of the key open research issues lies in dealing with structural aspects of text when analyzing its conveyed sentiment. Recent work uses structural aspects of text in order to distinguish important text s

  15. Generalized Structured Component Analysis with Latent Interactions

    Science.gov (United States)

    Hwang, Heungsun; Ho, Moon-Ho Ringo; Lee, Jonathan

    2010-01-01

    Generalized structured component analysis (GSCA) is a component-based approach to structural equation modeling. In practice, researchers may often be interested in examining the interaction effects of latent variables. However, GSCA has been geared only for the specification and testing of the main effects of variables. Thus, an extension of GSCA…

  16. Protein structure validation and refinement using amide proton chemical shifts derived from quantum mechanics.

    Directory of Open Access Journals (Sweden)

    Anders S Christensen

    Full Text Available We present the ProCS method for the rapid and accurate prediction of protein backbone amide proton chemical shifts--sensitive probes of the geometry of key hydrogen bonds that determine protein structure. ProCS is parameterized against quantum mechanical (QM calculations and reproduces high level QM results obtained for a small protein with an RMSD of 0.25 ppm (r = 0.94. ProCS is interfaced with the PHAISTOS protein simulation program and is used to infer statistical protein ensembles that reflect experimentally measured amide proton chemical shift values. Such chemical shift-based structural refinements, starting from high-resolution X-ray structures of Protein G, ubiquitin, and SMN Tudor Domain, result in average chemical shifts, hydrogen bond geometries, and trans-hydrogen bond ((h3J(NC' spin-spin coupling constants that are in excellent agreement with experiment. We show that the structural sensitivity of the QM-based amide proton chemical shift predictions is needed to obtain this agreement. The ProCS method thus offers a powerful new tool for refining the structures of hydrogen bonding networks to high accuracy with many potential applications such as protein flexibility in ligand binding.

  17. Protein structure validation and refinement using amide proton chemical shifts derived from quantum mechanics

    CERN Document Server

    Christensen, Anders S; Borg, Mikael; Boomsma, Wouter; Lindorff-Larsen, Kresten; Hamelryck, Thomas; Jensen, Jan H

    2013-01-01

    We present the ProCS method for the rapid and accurate prediction of protein backbone amide proton chemical shifts - sensitive probes of the geometry of key hydrogen bonds that determine protein structure. ProCS is parameterized against quantum mechanical (QM) calculations and reproduces high level QM results obtained for a small protein with an RMSD of 0.25 ppm (r = 0.94). ProCS is interfaced with the PHAISTOS protein simulation program and is used to infer statistical protein ensembles that reflect experimentally measured amide proton chemical shift values. Such chemical shift-based structural refinements, starting from high-resolution X-ray structures of Protein G, ubiquitin, and SMN Tudor Domain, result in average chemical shifts, hydrogen bond geometries, and trans-hydrogen bond (h3JNC') spin-spin coupling constants that are in excellent agreement with experiment. We show that the structural sensitivity of the QM-based amide proton chemical shift predictions is needed to refine protein structures to this...

  18. Synthesis of Cobalt Oxides Thin Films Fractal Structures by Laser Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    P. Haniam

    2014-01-01

    Full Text Available Thin films of cobalt oxides (CoO and Co3O4 fractal structures have been synthesized by using laser chemical vapor deposition at room temperature and atmospheric pressure. Various factors which affect the density and crystallization of cobalt oxides fractal shapes have been examined. We show that the fractal structures can be described by diffusion-limited aggregation model and discuss a new possibility to control the fractal structures.

  19. Structure and properties of braided sleeve preforms for chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

    Starr, T.L.; Fiadzo, O.G.; Hablutzel, N. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Materials Science and Technology

    1998-04-01

    In all composites the properties and structure of the reinforcement strongly influence the performance of the material. For some composites, however, the reinforcement also affects the fabrication process itself exerting an additional, second order influence on performance. This is the case for the chemical vapor infiltration (CVI) process for fabrication of ceramic matrix composites. In this process the matrix forms progressively as a solid deposit, first onto the fiber surfaces, then onto the previous layer of deposit, ultimately growing to fill the inter-fiber porosity. The transport of reactants to the surfaces and the evolved morphology of the matrix depend on the initial reinforcement structure. This structure can vary greatly and is controlled by such factors as fiber size and cross-section, the number of filaments and amount of twist per tow or yarn, and the weave or braid architecture. Often the choice of reinforcement is based on mechanical performance analysis or on the cost and availability of the material or on the temperature stability of the fiber. Given this choice, the composite densification process--CVI--must be optimized to attain a successful material. Ceramic fiber in the form of cylindrical braided sleeve is an attractive choice for fabrication of tube-form ceramic matrix composites. Multiple, concentric layers of sleeve can be placed over a tubular mandrel, compressed and fixed with a binder to form a freestanding tube preform. This fiber architecture is different than that created by layup of plain weave cloth--the material used in most previous CVI development. This report presents the results of the investigation of CVI densification of braided sleeve preforms and the evolution of their structure and transport properties during processing.

  20. Structure-mechanism-based engineering of chemical regulators targeting distinct pathological factors in Alzheimer's disease

    Science.gov (United States)

    Beck, Michael W.; Derrick, Jeffrey S.; Kerr, Richard A.; Oh, Shin Bi; Cho, Woo Jong; Lee, Shin Jung C.; Ji, Yonghwan; Han, Jiyeon; Tehrani, Zahra Aliakbar; Suh, Nayoung; Kim, Sujeong; Larsen, Scott D.; Kim, Kwang S.; Lee, Joo-Yong; Ruotolo, Brandon T.; Lim, Mi Hee

    2016-10-01

    The absence of effective therapeutics against Alzheimer's disease (AD) is a result of the limited understanding of its multifaceted aetiology. Because of the lack of chemical tools to identify pathological factors, investigations into AD pathogenesis have also been insubstantial. Here we report chemical regulators that demonstrate distinct specificity towards targets linked to AD pathology, including metals, amyloid-β (Aβ), metal-Aβ, reactive oxygen species, and free organic radicals. We obtained these chemical regulators through a rational structure-mechanism-based design strategy. We performed structural variations of small molecules for fine-tuning their electronic properties, such as ionization potentials and mechanistic pathways for reactivity towards different targets. We established in vitro and/or in vivo efficacies of the regulators for modulating their targets' reactivities, ameliorating toxicity, reducing amyloid pathology, and improving cognitive deficits. Our chemical tools show promise for deciphering AD pathogenesis and discovering effective drugs.

  1. Structural and spectroscopic evidence for stable chemical bonds and the correlation with high Tc superconductivity

    International Nuclear Information System (INIS)

    It is discovered that in the high-Tc superconducting YBa2−xLaxCu3Oz system, by structural analysis and Raman spectroscopy, a stable ‘fixed triangle’ structure exists in the CuO2 planes. All chemical bonds and angles constituting the O(3)–Cu(2)–O(2) triangle are almost constant with doping. The frequencies and linewidths of the out-of-phase c-axis O(2)–O(3) buckling modes around 337 cm−1 and the in-plane Cu(2)–O(2) bond stretching modes around 534 cm−1 are both independent of the doping level, providing direct evidence for the stability of this fixed triangle. It was previously revealed that just these two phonons couple strongly with the antinodal and nodal electronic states, respectively, resulting in an anisotropic electron–phonon interaction in the cuprates. This work implies that the stability of the CuO2 subunit and phonons related to it might be quite important in inducing the d-wave high-Tc superconductivity and should be paid more attention. (paper)

  2. The effect of chemical structure of dimethyl ether (DME) on NOx formation in nonpremixed counterflow flames

    International Nuclear Information System (INIS)

    To clarify the effect of chemical structure of Dimethyl ether(DME) on NOx formation in nonpremixed counterflow flame, DME flame was investigated numerically to compare the flame structures and NOx emissions with C2H6 and Mixed-fuel. Numerically, the governing equations were solved using the Oppdif code coupled with CHEMKIN package, and DME flames were calculated by Kaiser's mechanism, while the C2H6 flames and Mixed-fuel flames were calculated by the C3 mechanism. These mechanisms were combined with the modified Miller-Bowman mechanism for the analysis of NOx. Numerical results of nonpremixed counterflow flames show that the EINO of DME nonpremixed flame is low as much as 50 % of the C2H6 nonpremixed flame. The cause of EINO reduction is attributed mainly to the characteristics of partial premixed flame due to the existence of oxygen atom in DME and partly to the O-C bond in DME, instead of C-C bond in hydrocarbon fuels

  3. Expanding the chemical space of polyketides through structure-guided mutagenesis of Vitis vinifera stilbene synthase.

    Science.gov (United States)

    Bhan, Namita; Cress, Brady F; Linhardt, Robert J; Koffas, Mattheos

    2015-08-01

    Several natural polyketides (PKs) have been associated with important pharmaceutical properties. Type III polyketide synthases (PKS) that generate aromatic PK polyketides have been studied extensively for their substrate promiscuity and product diversity. Stilbene synthase-like (STS) enzymes are unique in the type III PKS class as they possess a hydrogen bonding network, furnishing them with thioesterase-like properties, resulting in aldol condensation of the polyketide intermediates formed. Chalcone synthases (CHS) in contrast, lack this hydrogen-bonding network, resulting primarily in the Claisen condensation of the polyketide intermediates formed. We have attempted to expand the chemical space of this interesting class of compounds generated by creating structure-guided mutants of Vitis vinifera STS. Further, we have utilized a previously established workflow to quickly compare the wild-type reaction products to those generated by the mutants and identify novel PKs formed by using XCMS analysis of LC-MS and LC-MS/MS data. Based on this approach, we were able to generate 15 previously unreported PK molecules by exploring the substrate promiscuity of the wild-type enzyme and all mutants using unnatural substrates. These structures were specific to STSs and cannot be formed by their closely related CHS-like counterparts. PMID:26048582

  4. Bayesian analysis of cosmic structures

    CERN Document Server

    Kitaura, Francisco-Shu

    2011-01-01

    We revise the Bayesian inference steps required to analyse the cosmological large-scale structure. Here we make special emphasis in the complications which arise due to the non-Gaussian character of the galaxy and matter distribution. In particular we investigate the advantages and limitations of the Poisson-lognormal model and discuss how to extend this work. With the lognormal prior using the Hamiltonian sampling technique and on scales of about 4 h^{-1} Mpc we find that the over-dense regions are excellent reconstructed, however, under-dense regions (void statistics) are quantitatively poorly recovered. Contrary to the maximum a posteriori (MAP) solution which was shown to over-estimate the density in the under-dense regions we obtain lower densities than in N-body simulations. This is due to the fact that the MAP solution is conservative whereas the full posterior yields samples which are consistent with the prior statistics. The lognormal prior is not able to capture the full non-linear regime at scales ...

  5. Polarity Analysis of Texts using Discourse Structure

    NARCIS (Netherlands)

    Heerschop, Bas; Goosen, Frank; Hogenboom, Alexander; Frasincar, Flavius; Kaymak, Uzay; Jong, de Franciska

    2011-01-01

    Sentiment analysis has applications in many areas and the exploration of its potential has only just begun. We propose Pathos, a framework which performs document sentiment analysis (partly) based on a document’s discourse structure. We hypothesize that by splitting a text into important and less im

  6. Structural Analysis of a Tracked Vehicle Hull .

    Directory of Open Access Journals (Sweden)

    M. Mala

    1997-04-01

    Full Text Available The hull of a tracked military vehicle is complex in geometry and loading pattern. Analytical studies were carried out using numerically integrated elements for system analysis (NISA, a general finite element programme developed by the Engineering Mechanics Research Corporation (EMRC, USA. Structural changes in the initial design were made to bring deflection within acceptable limits. Dynamic stress levels for the hull structure, were determined from strain gauge measurements. The resultant stresses were obtained adding the static and dynamic values. Finite element analysis was found to be very useful to check the rigidity of the structure at design stage and to suggest suitable design stage and to suggest suitable modifications.

  7. Chemical hazards analysis of resilient flooring for healthcare.

    Science.gov (United States)

    Lent, Tom; Silas, Julie; Vallette, Jim

    2010-01-01

    This article addresses resilient flooring, evaluating the potential health effects of vinyl flooring and the leading alternatives-synthetic rubber, polyolefin, and linoleum-currently used in the healthcare marketplace. The study inventories chemicals incorporated as components of each of the four material types or involved in their life cycle as feedstocks, intermediary chemicals, or emissions. It then characterizes those chemicals using a chemical hazard-based framework that addresses persistence and bioaccumulation, human toxicity, and human exposures. PMID:21165873

  8. Structural Analysis Of Offshore Structures Exposed To Blast Loads

    DEFF Research Database (Denmark)

    Hansen, Hans Jakup; Thygesen, Ulf; Kristensen, Anders;

    2002-01-01

    Numerical methods for simulations of blast loads and resulting structural response are investigated and compared to results obtained from tests. The CFD code EXSIM is used for the simulation of the blast load. This code provides a load profile wich is entered in the FEM analysis model....

  9. Identification of Lilial as a fragrance sensitizer in a perfume by bioassay-guided chemical fractionation and structure-activity relationships.

    Science.gov (United States)

    Arnau, E G; Andersen, K E; Bruze, M; Frosch, P J; Johansen, J D; Menné, T; Rastogi, S C; White, I R; Lepoittevin, J P

    2000-12-01

    Fragrance materials are among the most common causes of allergic contact dermatitis. The aim of this study was to identify in a perfume fragrance allergens not included in the fragrance mix, by use of bioassay-guided chemical fractionation and chemical analysis/structure-activity relationships (SARs). The basis for the investigation was a 45-year-old woman allergic to her own perfume. She had a negative patch test to the fragrance mix and agreed to participate in the study. Chemical fractionation of the perfume concentrate was used for repeated patch testing and/or repeated open application test on the pre-sensitized patient. The chemical composition of the fractions giving a positive patch-test response and repeated open application test reactions was obtained by gas chromatography-mass spectrometry. From the compounds identified, those that contained a "structural alert" in their chemical structure, indicating an ability to modify skin proteins and thus behave as a skin sensitizer, were tested on the patient. The patient reacted positively to the synthetic fragrance p-t-butyl-alpha-methylhydrocinnamic aldehyde (Lilial), a widely used fragrance compound not present in the fragrance mix. The combination of bioassay-guided chemical fractionation and chemical analysis/structure-activity relationships seems to be a valuable tool for the investigation of contact allergy to fragrance materials.

  10. Chemical analysis of Argonne premium coal samples. Bulletin

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, C.A.

    1997-11-01

    Contents: The Chemical Analysis of Argonne Premium Coal Samples: An Introduction; Rehydration of Desiccated Argonne Premium Coal Samples; Determination of 62 Elements in 8 Argonne Premium Coal Ash Samples by Automated Semiquantitative Direct-Current Arc Atomic Emission Spectrography; Determination of 18 Elements in 5 Whole Argonne Premium Coal Samples by Quantitative Direct-Current Arc Atomic Emission Spectrography; Determination of Major and Trace Elements in Eight Argonne Premium Coal Samples (Ash and Whole Coal) by X-Ray Fluorescence Spectrometry; Determination of 29 Elements in 8 Argonne Premium Coal Samples by Instrumental Neutron Activation Analysis; Determination of Selected Elements in Coal Ash from Eight Argonne Premium Coal Samples by Atomic Absorption Spectrometry and Atomic Emission Spectrometry; Determination of 25 Elements in Coal Ash from 8 Argonne Premium Coal Samples by Inductively Coupled Argon Plasma-Atomic Emission Spectrometry; Determination of 33 Elements in Coal Ash from 8 Argonne Premium Coal Samples by Inductively Coupled Argon Plasma-Mass Spectrometry; Determination of Mercury and Selenium in Eight Argonne Premium Coal Samples by Cold-Vapor and Hydride-Generation Atomic Absorption Spectrometry; Determinaton of Carbon, Hydrogen, and Nitrogen in Eight Argonne Premium Coal Samples by Using a Gas Chromatographic Analyzer with a Thermal Conductivity Detector; and Compilation of Multitechnique Determinations of 51 Elements in 8 Argonne Premium Coal Samples.

  11. Chemical analysis and potential health risks of hookah charcoal.

    Science.gov (United States)

    Elsayed, Yehya; Dalibalta, Sarah; Abu-Farha, Nedal

    2016-11-01

    Hookah (waterpipe) smoking is a very common practice that has spread globally. There is growing evidence on the hazardous consequences of smoking hookah, with studies indicating that its harmful effects are comparable to cigarette smoking if not worse. Charcoal is commonly used as a heating source for hookah smoke. Although charcoal briquettes are thought to be one of the major contributors to toxicity, their composition and impact on the smoke generated remains largely unidentified. This study aims to analyze the elemental composition of five different raw synthetic and natural charcoals by using Carbon-Hydrogen-Nitrogen (CHN) analysis, inductively coupled plasma (ICP), and scanning electron microscopy coupled with energy dispersive X-Ray spectrometry (SEM-EDS). Elemental analysis showed that the raw charcoals contain heavy metals such as zinc, iron, cadmium, vanadium, aluminum, lead, chromium, manganese and cobalt at concentrations similar, if not higher than, cigarettes. In addition, thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) was used to analyze the chemical composition of the smoke produced from burning the charcoal samples. The smoke emitted from charcoal was found to be the source of numerous compounds which could be hazardous to health. A total of seven carcinogens, 39 central nervous system depressants and 31 respiratory irritants were identified. PMID:27343945

  12. Structural-Thermal-Optical-Performance (STOP) Analysis

    Science.gov (United States)

    Bolognese, Jeffrey; Irish, Sandra

    2015-01-01

    The presentation will be given at the 26th Annual Thermal Fluids Analysis Workshop (TFAWS 2015) hosted by the Goddard Spaceflight Center (GSFC) Thermal Engineering Branch (Code 545). A STOP analysis is a multidiscipline analysis, consisting of Structural, Thermal and Optical Performance Analyses, that is performed for all space flight instruments and satellites. This course will explain the different parts of performing this analysis. The student will learn how to effectively interact with each discipline in order to accurately obtain the system analysis results.

  13. Electronic structure and chemical bond nature in Cs2PuO2Cl4

    Directory of Open Access Journals (Sweden)

    Teterin Yury A.

    2015-01-01

    Full Text Available X-ray photoelectron spectral analysis of dicaesiumtetrachlorodioxoplutonate (Cs2PuO2Cl4 single crystal was done in the binding energy range 0-~35 eV on the basis of binding energies and structure of the core electronic shells (~35 eV-1250 eV, as well as the relativistic discrete variation calculation results for the PuO2Cl4 (D4h. This cluster reflects Pu close environment in Cs2PuO2Cl4 containing the plutonyl group PuO2. The many-body effects due to the presence of cesium and chlorine were shown to contribute to the outer valence (0-~15 eV binding energy spectral structure much less than to the inner valence (~15 eV- ~35 eV binding energy one. The filled Pu 5f electronic states were theoretically calculated and experimentally con- firmed to present in the valence band of Cs2PuO2Cl4. It corroborates the suggestion on the direct participation of the Pu 5f electrons in the chemical bond. The Pu 6p atomic orbitals were shown to participate in formation of both the inner and the outer valence molecular orbitals (bands, while the filled Pu 6p and O 2s, Cl 3s electronic shells were found to take the largest part in formation of the inner valence molecular orbitals. The composition of molecular orbitals and the sequence order in the binding energy range 0-~35 eV in Cs2PuO2Cl4 were established. The quantitative scheme of molecular orbitals for Cs2PuO2Cl4 in the binding energy range 0-~15 eV was built on the basis of the experimental and theoretical data. It is fundamental for both understanding the chemical bond nature in Cs2PuO2Cl4 and the interpretation of other X-ray spectra of Cs2PuO2Cl4. The contributions to the chemical binding for the PuO2Cl4 cluster were evaluated to be: the contribution of the outer valence molecular orbitals -66 %, the contribution of the inner valence molecular orbitals -34 %.

  14. Protein structure similarity clustering (PSSC) and natural product structure as inspiration sources for drug development and chemical genomics

    NARCIS (Netherlands)

    Dekker, Frank J; Koch, Marcus A; Waldmann, Herbert; Dekker, Frans

    2005-01-01

    Finding small molecules that modulate protein function is of primary importance in drug development and in the emerging field of chemical genomics. To facilitate the identification of such molecules, we developed a novel strategy making use of structural conservatism found in protein domain architec

  15. Safety- and Risk Analysis Activities in Chemical Industry in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Kozine, Igor; Duijm, Nijs Jan; Lauridsen Kurt [Risoe National Laboratory, Roskilde (Denmark). Systems Analysis Department

    2001-07-01

    The current paper gives an overview of the legislation and the methods used in safety and risk management in the chemical industry within Europe and in particular within the European Union. The paper is based on a report that has been written for the SOS-1 project under the Nordic nuclear safety research (NKS). Safety- and risk-related matters in the process industry, in particular, in chemical, within the EU are subject to consideration at three levels: (1) EU legislation, (2) European/intemational standardisation, and (3) socio-economic analysis. EC Directives define the 'essential requirements', e.g., protection of health and safety, that must be fulfilled when goods are placed on the market or some industry is put into operation. The European standards bodies (CEN, CENELEC and ETSI) have the task of establishing the corresponding technical specifications, meeting the essential requirements of the Directives, compliance with which will provide a presumption of conformity with the essential requirements. Such specifications are referred to as 'harmonised standards'. Compliance with harmonised standards remains voluntary, and manufacturers are free to choose any other technical solution that provides compliance with the essential requirements. This view is stated in the 'New Approach' to technical harmonisation and standardisation (details can be found on the web page: http://europe.eu.int/comm/enterprise/newapproach/standardization/index .html). Standardisation as well as the regulation of technical risks is increasingly being undertaken at European or international level. The European legislator limits its role to the affirmation of overall objectives, and leaves it to the economic players to draw up the technical procedures and standards to specify in detail the ways and means of attaining them. Many countries have introduced requirements that new legislation and/or administrative regulations be subject to socio-economic analysis

  16. Meta-Analysis of the Chemical and Non-Chemical Stressors Affecting Childhood Obesity

    Science.gov (United States)

    Worldwide, approximately 42 million children under the age of 5 years are considered overweight or obese. While much research has focused on individual behaviors impacting obesity, little research has emphasized the complex interactions of numerous chemical and non-chemical stres...

  17. The chemical structure of the ZnO/SiC heterointerface as revealed by electron spectroscopies

    International Nuclear Information System (INIS)

    ZnO layers were deposited on 6H-SiC single crystalline wafers by radio frequency magnetron sputtering. The chemical structure of the ZnO/SiC interface was studied by x-ray photoelectron and x-ray excited Auger electron spectroscopy. A complex chemical structure, involving not only silicon–carbon and zinc–oxygen bonds but also silicon–oxygen and zinc–silicon–oxygen bonds was revealed to form at the ZnO/SiC interface. Based on the comparison with the presumably inert (i.e. chemically abrupt) ZnO/Mo interface, it was concluded that a willemite-like zinc silicate (i.e. Zn2SiO4) interface species develops between ZnO and SiC. The presence of this species at the ZnO/SiC interface will affect the electronic structure of the heterojunction and thus needs to be considered for device optimization. (paper)

  18. Kinematic Analysis of a Hybrid Structure

    Directory of Open Access Journals (Sweden)

    Duan Q.J.

    2012-11-01

    Full Text Available This paper presents a kinematic analysis and simulation of a hybrid structure applied to the new design cable‐suspended feed structure (CSFS for the next generation of large spherical radio telescopes. First, considering the requirement that feeds should be tilted from 40° to 60° and that the tracking precision in steady state is 4mm, a novel design of the feed supporting structure including a cable‐cabin structure, an AB axis structure and a Stewart platform is performed. Next, kinematic analysis and the simulation of the CSFS are done. Simulations have been developed in combination with the 50m CSFS model, which demonstrate the effectiveness and feasibility of the proposed three‐level cable‐suspended feed system.

  19. Probabilistic structural analysis computer code (NESSUS)

    Science.gov (United States)

    Shiao, Michael C.

    1988-01-01

    Probabilistic structural analysis has been developed to analyze the effects of fluctuating loads, variable material properties, and uncertain analytical models especially for high performance structures such as SSME turbopump blades. The computer code NESSUS (Numerical Evaluation of Stochastic Structure Under Stress) was developed to serve as a primary computation tool for the characterization of the probabilistic structural response due to the stochastic environments by statistical description. The code consists of three major modules NESSUS/PRE, NESSUS/FEM, and NESSUS/FPI. NESSUS/PRE is a preprocessor which decomposes the spatially correlated random variables into a set of uncorrelated random variables using a modal analysis method. NESSUS/FEM is a finite element module which provides structural sensitivities to all the random variables considered. NESSUS/FPI is Fast Probability Integration method by which a cumulative distribution function or a probability density function is calculated.

  20. ACTINIDE REMOVAL PROCESS SAMPLE ANALYSIS, CHEMICAL MODELING, AND FILTRATION EVALUATION

    Energy Technology Data Exchange (ETDEWEB)

    Martino, C.; Herman, D.; Pike, J.; Peters, T.

    2014-06-05

    Filtration within the Actinide Removal Process (ARP) currently limits the throughput in interim salt processing at the Savannah River Site. In this process, batches of salt solution with Monosodium Titanate (MST) sorbent are concentrated by crossflow filtration. The filtrate is subsequently processed to remove cesium in the Modular Caustic Side Solvent Extraction Unit (MCU) followed by disposal in saltstone grout. The concentrated MST slurry is washed and sent to the Defense Waste Processing Facility (DWPF) for vitrification. During recent ARP processing, there has been a degradation of filter performance manifested as the inability to maintain high filtrate flux throughout a multi-batch cycle. The objectives of this effort were to characterize the feed streams, to determine if solids (in addition to MST) are precipitating and causing the degraded performance of the filters, and to assess the particle size and rheological data to address potential filtration impacts. Equilibrium modelling with OLI Analyzer{sup TM} and OLI ESP{sup TM} was performed to determine chemical components at risk of precipitation and to simulate the ARP process. The performance of ARP filtration was evaluated to review potential causes of the observed filter behavior. Task activities for this study included extensive physical and chemical analysis of samples from the Late Wash Pump Tank (LWPT) and the Late Wash Hold Tank (LWHT) within ARP as well as samples of the tank farm feed from Tank 49H. The samples from the LWPT and LWHT were obtained from several stages of processing of Salt Batch 6D, Cycle 6, Batch 16.

  1. Surface Nano Structures Manufacture Using Batch Chemical Processing Methods for Tooling Applications

    DEFF Research Database (Denmark)

    Tosello, Guido; Calaon, Matteo; Gavillet, J.;

    2011-01-01

    The patterning of large surface areas with nano structures by using chemical batch processes to avoid using highenergy intensive nano machining processes was investigated. The capability of different surface treatment methods of creating micro and nano structured adaptable mould inserts...... for subsequent polymer replication by injection moulding was analyzed. New tooling solutions to produce nano structured mould surfaces were investigated. Experiments based on three different chemical-based-batch techniques to establish surface nano (i.e. sub-μm) structures on large areas were performed. Three...... approaches were selected: (1) using Ø500 nm nano beads deposition for direct patterning of a 4” silicon wafer; (2) using Ø500 nm nano beads deposition as mask for 4” silicon wafer etching and subsequent nickel electroplating; (3) using the anodizing process to produce Ø500 nm structures on a 30x80 mm2...

  2. Fragment-Based Electronic Structure Approach for Computing Nuclear Magnetic Resonance Chemical Shifts in Molecular Crystals.

    Science.gov (United States)

    Hartman, Joshua D; Beran, Gregory J O

    2014-11-11

    First-principles chemical shielding tensor predictions play a critical role in studying molecular crystal structures using nuclear magnetic resonance. Fragment-based electronic structure methods have dramatically improved the ability to model molecular crystal structures and energetics using high-level electronic structure methods. Here, a many-body expansion fragment approach is applied to the calculation of chemical shielding tensors in molecular crystals. First, the impact of truncating the many-body expansion at different orders and the role of electrostatic embedding are examined on a series of molecular clusters extracted from molecular crystals. Second, the ability of these techniques to assign three polymorphic forms of the drug sulfanilamide to the corresponding experimental (13)C spectra is assessed. This challenging example requires discriminating among spectra whose (13)C chemical shifts differ by only a few parts per million (ppm) across the different polymorphs. Fragment-based PBE0/6-311+G(2d,p) level chemical shielding predictions correctly assign these three polymorphs and reproduce the sulfanilamide experimental (13)C chemical shifts with 1 ppm accuracy. The results demonstrate that fragment approaches are competitive with the widely used gauge-invariant projector augmented wave (GIPAW) periodic density functional theory calculations. PMID:26584373

  3. FEM structural analysis of ITER gravity supports

    International Nuclear Information System (INIS)

    Because of the complexity of the load cases, the gravity support of ITER endures several large forces during operation besides the dead weight of the magnet system, such as electromagnetic force on the magnets, thermal load and seismic loads (SL). In order to verify the reliability of the design, and make the gravity support operate safely under the various load cases, it is very important to analyze the applied force on the gravity support in different load cases. In this paper, finite-element-method (FEM) is used for the structural analysis. 3-D FEM models of the overall gravity support system, with 20 degree sector and 360 degree respectively, are created by ANSYS according to different load cases. The 20 degree model in the torus is used for the structural analysis of the gravity support system under the several symmetric load combinations, and the 360 degree model is used for the structural analysis under the load combinations with the asymmetric SL. The analysis results are given, such as the static structural analysis and the buckling analysis for the different load combinations, and the modal analysis for the natural frequencies. The calculation results reveal that all of the gravity support components have enough safety margins against various load combinations. (authors)

  4. Structure and local chemical properties of boron-terminated tetravacancies in hexagonal boron nitride.

    Science.gov (United States)

    Cretu, Ovidiu; Lin, Yung-Chang; Koshino, Masanori; Tizei, Luiz H G; Liu, Zheng; Suenaga, Kazutomo

    2015-02-20

    Imaging and spectroscopy performed in a low-voltage scanning transmission electron microscope are used to characterize the structure and chemical properties of boron-terminated tetravacancies in hexagonal boron nitride. We confirm earlier theoretical predictions about the structure of these defects and identify new features in the electron energy-loss spectra of B atoms using high resolution chemical maps, highlighting differences between these areas and pristine sample regions. We correlate our experimental data with calculations which help explain our observations. PMID:25763963

  5. Biosynthesis, Chemical Structure, and Structure-Activity Relationship of Orfamide Lipopeptides Produced by Pseudomonas protegens and Related Species.

    Science.gov (United States)

    Ma, Zongwang; Geudens, Niels; Kieu, Nam P; Sinnaeve, Davy; Ongena, Marc; Martins, José C; Höfte, Monica

    2016-01-01

    Orfamide-type cyclic lipopeptides (CLPs) are biosurfactants produced by Pseudomonas and involved in lysis of oomycete zoospores, biocontrol of Rhizoctonia and insecticidal activity against aphids. In this study, we compared the biosynthesis, structural diversity, in vitro and in planta activities of orfamides produced by rhizosphere-derived Pseudomonas protegens and related Pseudomonas species. Genetic characterization together with chemical identification revealed that the main orfamide compound produced by the P. protegens group is orfamide A, while the related strains Pseudomonas sp. CMR5c and CMR12a produce orfamide B. Comparison of orfamide fingerprints led to the discovery of two new orfamide homologs (orfamide F and orfamide G) in Pseudomonas sp. CMR5c. The structures of these two CLPs were determined by nuclear magnetic resonance (NMR) and mass spectrometry (MS) analysis. Mutagenesis and complementation showed that orfamides determine the swarming motility of parental Pseudomonas sp. strain CMR5c and their production was regulated by luxR type regulators. Orfamide A and orfamide B differ only in the identity of a single amino acid, while orfamide B and orfamide G share the same amino acid sequence but differ in length of the fatty acid part. The biological activities of orfamide A, orfamide B, and orfamide G were compared in further bioassays. The three compounds were equally active against Magnaporthe oryzae on rice, against Rhizoctonia solani AG 4-HGI in in vitro assays, and caused zoospore lysis of Phytophthora and Pythium. Furthermore, we could show that orfamides decrease blast severity in rice plants by blocking appressorium formation in M. oryzae. Taken all together, our study shows that orfamides produced by P. protegens and related species have potential in biological control of a broad spectrum of fungal plant pathogens. PMID:27065956

  6. Biosynthesis, chemical structure and structure-activity relationship of orfamide lipopeptides produced by Pseudomonas protegens and related species

    Directory of Open Access Journals (Sweden)

    Zongwang eMa

    2016-03-01

    Full Text Available Orfamide-type cyclic lipopeptides (CLPs are biosurfactants produced by Pseudomonas and involved in lysis of oomycete zoospores, biocontrol of Rhizoctonia and insecticidal activity against aphids. In this study we compared the biosynthesis, structural diversity, in vitro and in planta activities of orfamides produced by rhizosphere-derived Pseudomonas protegens and related Pseudomonas species. Genetic characterization together with chemical identification revealed that the main orfamide compound produced by the P. protegens group is orfamide A, while the related strains Pseudomonas sp. CMR5c and CMR12a produce orfamide B. Comparison of orfamide fingerprints led to the discovery of two new orfamide homologues (orfamide F and orfamide G in Pseudomonas sp. CMR5c. The structures of these two CLPs were determined by nuclear magnetic resonance (NMR and mass spectrometry (MS analysis. Mutagenesis and complementation showed that orfamides determine the swarming motility of parental Pseudomonas sp. strain CMR5c and their production was regulated by luxR type regulators. Orfamide A and orfamide B differ only in the identity of a single amino acid, while orfamide B and orfamide G share the same amino acid sequence but differ in length of the fatty acid part. The biological activities of orfamide A, orfamide B and orfamide G were compared in further bioassays. The three compounds were equally active against Magnaporthe oryzae on rice, against Rhizoctonia solani AG 4-HGI in in vitro assays, and caused zoospore lysis of Phytophthora and Pythium. Furthermore we could show that orfamides decrease blast severity in rice plants by blocking appressorium formation in M. oryzae. Taken all together, our study shows that orfamides produced by P. protegens and related species have potential in biological control of a broad spectrum of fungal plant pathogens.

  7. Nontarget effects of chemical pesticides and biological pesticide on rhizospheric microbial community structure and function in Vigna radiata.

    Science.gov (United States)

    Singh, Sunil; Gupta, Rashi; Kumari, Madhu; Sharma, Shilpi

    2015-08-01

    Intensive agriculture has resulted in an indiscriminate use of pesticides, which demands in-depth analysis of their impact on indigenous rhizospheric microbial community structure and function. Hence, the objective of the present work was to study the impact of two chemical pesticides (chlorpyrifos and cypermethrin) and one biological pesticide (azadirachtin) at two dosages on the microbial community structure using cultivation-dependent approach and on rhizospheric bacterial communities involved in nitrogen cycle in Vigna radiata rhizosphere through cultivation-independent technique of real-time PCR. Cultivation-dependent study highlighted the adverse effects of both chemical pesticide and biopesticide on rhizospheric bacterial and fungal communities at different plant growth stages. Also, an adverse effect on number of genes and transcripts of nifH (nitrogen fixation); amoA (nitrification); and narG, nirK, and nirS (denitrification) was observed. The results from the present study highlighted two points, firstly that nontarget effects of pesticides are significantly detrimental to soil microflora, and despite being of biological origin, azadirachtin exerted negative impact on rhizospheric microbial community of V. radiata behaving similar to chemical pesticides. Hence, such nontarget effects of chemical pesticide and biopesticide in plants' rhizosphere, which bring out the larger picture in terms of their ecotoxicological effect, demand a proper risk assessment before application of pesticides as agricultural amendments. PMID:25801369

  8. THE INFLUENCE OF THE COMPLEX CHEMICAL ADDITIVE CONTAINING THE STRUCTURED CARBON NANOMATERIAL ON PROPERTIES OF CEMENT

    Directory of Open Access Journals (Sweden)

    O. Yu. Sheyda

    2015-01-01

    Full Text Available The paper presents results of investigations on influence of domestic complex chemical additive containing structured carbon nanomaterial and characterized by a combination effect (curing acceleration and plasticizing on cement and cement stone properties. The purpose of the investigations, on the one hand, has been to confirm efficacy of УКД-1additive from the perspective for increasing the rate of gain, strength growth of cement concrete and additive influence on setting time with the purpose to preserve molding properties of concrete mixes in time, and on the other hand, that is to assess “mechanism” of the УКД-1 additive action in the cement concrete. The research results have revealed regularities in changes due to the additive of water requirements and time period of the cement setting. The reqularities are considered as a pre-requisite for relevant changes in molding properties of the concrete mixes. The paper also experimentally substantiates the possibility to decrease temperature of cement concrete heating with the УДК-1 additive. It has been done with the purpose to save energy resources under production conditions. In addition to this the paper proves the efficiency of the additive which is expressed in strength increase of cement stone up to 20–40 % in the rated age (28 days that is considered as a basis for strength growth of cement concrete. The paper confirms a hypothesis on physical nature of this phenomenon because the X-ray phase analysis method has shown that there are no changes in morphology of portland cement hydration products under the action of the additive agent containing a structured carbon nanomaterial. Results of theoretical and experimental investigations on УКД-1 additive efficiency have been proved by industrial approbation while fabricating precast concrete products and construction of monolithic structures under plant industrial conditions (Minsk, SS “Stroyprogress” JSC MAPID and on

  9. Application of chemical structure and bonding of actinide oxide materials for forensic science

    Energy Technology Data Exchange (ETDEWEB)

    Wilkerson, Marianne Perry [Los Alamos National Laboratory

    2010-01-01

    We are interested in applying our understanding of actinide chemical structure and bonding to broaden the suite of analytical tools available for nuclear forensic analyses. Uranium- and plutonium-oxide systems form under a variety of conditions, and these chemical species exhibit some of the most complex behavior of metal oxide systems known. No less intriguing is the ability of AnO{sub 2} (An: U, Pu) to form non-stoichiometric species described as AnO{sub 2+x}. Environmental studies have shown the value of utilizing the chemical signatures of these actinide oxide materials to understand transport following release into the environment. Chemical speciation of actinide-oxide samples may also provide clues as to the age, source, or process history of the material. The scientific challenge is to identify, measure and understand those aspects of speciation of actinide analytes that carry information about material origin and history most relevant to forensics. Here, we will describe our efforts in material synthesis and analytical methods development that we will use to provide the fundamental science to characterize actinide oxide molecular structures for forensic science. Structural properties and initial results to measure structural variability of uranium oxide samples using synchrotron-based X-ray Absorption Fine Structure will be discussed.

  10. Application of chemical structure and bonding of actinide oxide materials for forensic science

    International Nuclear Information System (INIS)

    We are interested in applying our understanding of actinide chemical structure and bonding to broaden the suite of analytical tools available for nuclear forensic analyses. Uranium- and plutonium-oxide systems form under a variety of conditions, and these chemical species exhibit some of the most complex behavior of metal oxide systems known. No less intriguing is the ability of AnO2 (An: U, Pu) to form non-stoichiometric species described as AnO2+x. Environmental studies have shown the value of utilizing the chemical signatures of these actinide oxide materials to understand transport following release into the environment. Chemical speciation of actinide-oxide samples may also provide clues as to the age, source, or process history of the material. The scientific challenge is to identify, measure and understand those aspects of speciation of actinide analytes that carry information about material origin and history most relevant to forensics. Here, we will describe our efforts in material synthesis and analytical methods development that we will use to provide the fundamental science to characterize actinide oxide molecular structures for forensic science. Structural properties and initial results to measure structural variability of uranium oxide samples using synchrotron-based X-ray Absorption Fine Structure will be discussed.

  11. Time-series metagenomic analysis reveals robustness of soil microbiome against chemical disturbance.

    Science.gov (United States)

    Kato, Hiromi; Mori, Hiroshi; Maruyama, Fumito; Toyoda, Atsushi; Oshima, Kenshiro; Endo, Ryo; Fuchu, Genki; Miyakoshi, Masatoshi; Dozono, Ayumi; Ohtsubo, Yoshiyuki; Nagata, Yuji; Hattori, Masahira; Fujiyama, Asao; Kurokawa, Ken; Tsuda, Masataka

    2015-12-01

    Soil microbial communities have great potential for bioremediation of recalcitrant aromatic compounds. However, it is unclear which taxa and genes in the communities, and how they contribute to the bioremediation in the polluted soils. To get clues about this fundamental question here, time-course (up to 24 weeks) metagenomic analysis of microbial community in a closed soil microcosm artificially polluted with four aromatic compounds, including phenanthrene, was conducted to investigate the changes in the community structures and gene pools. The pollution led to drastic changes in the community structures and the gene sets for pollutant degradation. Complete degradation of phenanthrene was strongly suggested to occur by the syntrophic metabolism by Mycobacterium and the most proliferating genus, Burkholderia. The community structure at Week 24 (∼12 weeks after disappearance of the pollutants) returned to the structure similar to that before pollution. Our time-course metagenomic analysis of phage genes strongly suggested the involvement of the 'kill-the-winner' phenomenon (i.e. phage predation of Burkholderia cells) for the returning of the microbial community structure. The pollution resulted in a decrease in taxonomic diversity and a drastic increase in diversity of gene pools in the communities, showing the functional redundancy and robustness of the communities against chemical disturbance.

  12. Influence of Chemical Conditions on the Nanoporous Structure of Silicate Aerogels

    Directory of Open Access Journals (Sweden)

    Katalin Sinkó

    2010-01-01

    Full Text Available Silica or various silicate aerogels can be characterized by highly porous, open cell, low density structures. The synthesis parameters influence the three-dimensional porous structures by modifying the kinetics and mechanism of hydrolysis and condensation processes. Numerous investigations have shown that the structure of porous materials can be tailored by variations in synthesis conditions (e.g., the type of precursors, catalyst, and surfactants; the ratio of water/precursor; the concentrations; the medium pH; and the solvent. The objectives of this review are to summarize and elucidate the effects of chemical conditions on the nanoporous structure of sol-gel derived silicate aerogels.

  13. Structural and XPS studies of PSi/TiO2 nanocomposites prepared by ALD and Ag-assisted chemical etching

    International Nuclear Information System (INIS)

    Highlights: • Porous silicon/TiO2 nanocomposites have been investigated. • Morphology and chemical composition of PSi/TiO2 nanocomposites were established. • Valence-band XPS maximums for PSi/TiO2 nanocomposites were found and analyzed. - Abstract: PSi/TiO2 nanocomposites fabricated by atomic layer deposition (ALD) and metal-assisted chemical etching (MACE) were investigated. The morphology and phase structure of PSi/TiO2 nanocomposites were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM) with an energy dispersive X-ray spectroscopy (EDX) and Raman spectroscopy. The mean size of TiO2 nanocrystals was determined by TEM and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical elemental composition by observing the behavior of the Ti 2p, O 1s and Si 2p lines. TEM, Raman spectroscopy and XPS binding energy analysis confirmed the formation of TiO2 anatase phase inside the PSi matrix. The XPS valence band analysis was performed in order to investigate the modification of PSi/TiO2 nanocomposites electronic structure. Surface defects states of Ti3+ at PSi/TiO2 nanocomposites were identified by analyzing of XPS valence band spectra

  14. A spectroscopic analysis of the chemically peculiar star HD207561

    CERN Document Server

    Joshi, S; Martinez, P; Sachkov, M; Joshi, Y C; Seetha, S; Chakradhari, N K; Mary, D L; Girish, V; Ashoka, B N

    2012-01-01

    In this paper we present a high-resolution spectroscopic analysis of the chemically peculiar star HD207561. During a survey programme to search for new roAp stars in the Northern hemisphere, Joshi et al. (2006) observed significant photometric variability on two consecutive nights in the year 2000. The amplitude spectra of the light curves obtained on these two nights showed oscillations with a frequency of 2.79 mHz [P~6-min]. However, subsequent follow-up observations could not confirm any rapid variability. In order to determine the spectroscopic nature of HD207561, high-resolution spectroscopic and spectro-polarimetric observations were carried out. A reasonable fit of the calculated Hbeta line profile to the observed one yields the effective temperature (Teff) and surface gravity (log g) as 7300 K and 3.7 dex, respectively. The derived projected rotational velocity (vsin i) for HD207561 is 74 km/sec indicative of a relatively fast rotator. The position of HD207561 in the H-R diagram implies that this is s...

  15. Microplasmas for chemical analysis: analytical tools or research toys?

    International Nuclear Information System (INIS)

    An overview of the activities of the research groups that have been involved in fabrication, development and characterization of microplasmas for chemical analysis over the last few years is presented. Microplasmas covered include: miniature inductively coupled plasmas (ICPs); capacitively coupled plasmas (CCPs); microwave-induced plasmas (MIPs); a dielectric barrier discharge (DBD); microhollow cathode discharge (MCHD) or microstructure electrode (MSE) discharges, other microglow discharges (such as those formed between 'liquid' electrodes); microplasmas formed in micrometer-diameter capillary tubes for gas chromatography (GC) or high-performance liquid chromatography (HPLC) applications, and a stabilized capacitive plasma (SCP) for GC applications. Sample introduction into microplasmas, in particular, into a microplasma device (MPD), battery operation of a MPD and of a mini- in-torch vaporization (ITV) microsample introduction system for MPDs, and questions of microplasma portability for use on site (e.g., in the field) are also briefly addressed using examples of current research. To emphasize the significance of sample introduction into microplasmas, some previously unpublished results from the author's laboratory have also been included. And an overall assessment of the state-of-the-art of analytical microplasma research is provided

  16. TECHNO-ECONOMIC ANALYSIS OF MODERNIZATION FOR CHEMICAL EQUIPMENT

    OpenAIRE

    Задольський, Аркадій Михайлович

    2015-01-01

    Industry of Ukraine is currently in a very difficult situation. This fully relates to the chemical industry. The real way to overcome negative developments, in the chemical industry, is improving its material base and objects of fixed assets. First of all, need improvement, machinery and equipment (chemical equipment). This important problem can be solved by upgrading existing equipment. In order to choose the most efficient option for replacement of obsolete equipment, should apply the techn...

  17. Similarity Analysis of Cable Insulations by Chemical Test

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Seog [Central Research Institute of Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2013-10-15

    As result of this experiment, it was found that FT-IR test for material composition, TGA test for aging trend are applicable for similarity analysis of cable materials. OIT is recommended as option if TGA doesn't show good trend. Qualification of new insulation by EQ report of old insulation should be based on higher activation energy of new insulation than that of old one in the consideration of conservatism. In old nuclear power plant, it is easy to find black cable which has no marking of cable information such as manufacturer, material name and voltage. If a type test is required for qualification of these cables, how could I select representative cable? How could I determine the similarity of these cables? If manufacturer has qualified a cable for nuclear power plant more than a decade ago and composition of cable material is changed with similar one, is it acceptable to use the old EQ report for recently manufactured cable? It is well known to use FT-IR method to determine the similarity of cable materials. Infrared ray is easy tool to compare compositions of each material. But, it is not proper to compare aging trend of these materials. Study for similarity analysis of cable insulation by chemical test is described herein. To study a similarity evaluation method for polymer materials, FT-IR, TGA and OIT tests were performed for two cable insulation(old and new) which were supplied from same manufacturer. FT-IR shows good result to compare material compositions while TGA and OIT show good result to compare aging character of materials.

  18. Analysis of flexible structures under lateral impact

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, D. F. [Paul C. Kizzo and Associates Inc., Seismic Structural Group, Oakland, CA 94612 (United States); Razavi, H. [AREVA Inc., Civil Seismic Group, San Jose, CA 95119 (United States)

    2012-07-01

    Three methods for analysis of flexible structures under lateral impact are presented. The first proposed method (Method A) consists of: (1) modifying an available deceleration on a rigid target with conservation principles to account for structural flexibility; and (2) transient nonlinear analysis of the structure with the corrected forcing function. The second proposed method (Method B) is similar to Method A in obtaining the forcing function but it solves the equations of motion of an idealized two-degree-of-freedom system instead of directly using conservation principles. The last method simply provides the maximum force in the structure using the conservation of energy and linear momentum. A coupled simulation is also performed in LS-DYNA and compared against the proposed methods. A case study is presented to illustrate the applicability of all three methods and the LS-DYNA simulation. (authors)

  19. Prediction algorithm for amino acid types with their secondary structure in proteins (PLATON) using chemical shifts

    Energy Technology Data Exchange (ETDEWEB)

    Labudde, D.; Leitner, D.; Krueger, M.; Oschkinat, H. [Forschungsinstitut fuer Molekulare Pharmakologie (Germany)], E-mail: oschkinat@fmp-berlin.de

    2003-01-15

    The algorithm PLATON is able to assign sets of chemical shifts derived from a single residue to amino acid types with its secondary structure (amino acid species). A subsequent ranking procedure using optionally two different penalty functions yields predictions for possible amino acid species for the given set of chemical shifts. This was demonstrated in the case of the {alpha}-spectrin SH3 domain and applied to 9 further protein data sets taken from the BioMagRes database. A database consisting of reference chemical shift patterns (reference CSPs) was generated from assigned chemical shifts of proteins with known 3D-structure. This reference CSP database is used in our approach for extracting distributions of amino acid types with their most likely secondary structure elements (namely {alpha}-helix, {beta}-sheet, and coil) for single amino acids by comparison with query CSPs. Results obtained for the 10 investigated proteins indicates that the percentage of correct amino acid species in the first three positions in the ranking list, ranges from 71.4% to 93.2% for the more favorable penalty function. Where only the top result of the ranking list for these 10 proteins is considered, 36.5% to 83.1% of the amino acid species are correctly predicted. The main advantage of our approach, over other methods that rely on average chemical shift values is the ability to increase database content by incorporating newly derived CSPs, and therefore to improve PLATON's performance over time.

  20. Prediction algorithm for amino acid types with their secondary structure in proteins (PLATON) using chemical shifts

    International Nuclear Information System (INIS)

    The algorithm PLATON is able to assign sets of chemical shifts derived from a single residue to amino acid types with its secondary structure (amino acid species). A subsequent ranking procedure using optionally two different penalty functions yields predictions for possible amino acid species for the given set of chemical shifts. This was demonstrated in the case of the α-spectrin SH3 domain and applied to 9 further protein data sets taken from the BioMagRes database. A database consisting of reference chemical shift patterns (reference CSPs) was generated from assigned chemical shifts of proteins with known 3D-structure. This reference CSP database is used in our approach for extracting distributions of amino acid types with their most likely secondary structure elements (namely α-helix, β-sheet, and coil) for single amino acids by comparison with query CSPs. Results obtained for the 10 investigated proteins indicates that the percentage of correct amino acid species in the first three positions in the ranking list, ranges from 71.4% to 93.2% for the more favorable penalty function. Where only the top result of the ranking list for these 10 proteins is considered, 36.5% to 83.1% of the amino acid species are correctly predicted. The main advantage of our approach, over other methods that rely on average chemical shift values is the ability to increase database content by incorporating newly derived CSPs, and therefore to improve PLATON's performance over time

  1. Chemical Structure and Immunomodulating Activities of an α-Glucan Purified from Lobelia chinensis Lour

    Directory of Open Access Journals (Sweden)

    Xiao-Jun Li

    2016-06-01

    Full Text Available A neutral α-glucan, named BP1, with a molecular mass of approximately 9.45 kDa, was isolated from Lobelia chinensis by hot-water extraction, a Q-Sepharose Fast Flow column and Superdex-75 column chromatography. Its chemical structure was characterized by monosaccharide analysis, methylation analysis and analysis of its FT-IR, high performance gel permeation chromatography (HPGPC and 1D/2D-NMR spectra data. The backbone of BP1 consists of →6α-d-Glcp1→6,3α-d-Glcp1→(6α-d-Glcp1x-6,3α-d-Glcp1-(6α-d-Glcp1y→. The side chains were terminal α-d-Glcp1→ and α-d-Glcp1→ (6α-d-Glcp1z→4α-d-Glcp1→3α-d-Glcp1→4α-d-Glcp1→ (x + y + z = 5, which are attached to the backbone at O-3 of 3,6α-d-Glcp1. The results of the effect of BP1 on mouse macrophage cell line RAW 264.7 indicate that BP1 enhances the cell proliferation, phagocytosis, nitric oxide production and cytokine secretion in a dose-dependent manner. Because the inhibitor of Toll-like receptor 4 blocks the BP1-induced secretion of TNF-α and IL-6, we hypothesize that α-glucan BP1 activates TLR4, which mediates the above-mentioned immunomodulating effects.

  2. Chemical Structure and Immunomodulating Activities of an α-Glucan Purified from Lobelia chinensis Lour.

    Science.gov (United States)

    Li, Xiao-Jun; Bao, Wan-Rong; Leung, Chung-Hang; Ma, Dik-Lung; Zhang, Ge; Lu, Ai-Ping; Wang, Shun-Chun; Han, Quan-Bin

    2016-01-01

    A neutral α-glucan, named BP1, with a molecular mass of approximately 9.45 kDa, was isolated from Lobelia chinensis by hot-water extraction, a Q-Sepharose Fast Flow column and Superdex-75 column chromatography. Its chemical structure was characterized by monosaccharide analysis, methylation analysis and analysis of its FT-IR, high performance gel permeation chromatography (HPGPC) and 1D/2D-NMR spectra data. The backbone of BP1 consists of →₆α-d-Glcp¹→6,3α-d-Glcp¹→(₆α-d-Glcp¹)x-6,3α-d-Glcp¹-(₆α-d-Glcp¹)y→. The side chains were terminal α-d-Glcp¹→ and α-d-Glcp¹→ (₆α-d-Glcp¹)z→₄α-d-Glcp¹→₃α-d-Glcp¹→₄α-d-Glcp¹→ (x + y + z = 5), which are attached to the backbone at O-3 of 3,6α-d-Glcp¹. The results of the effect of BP1 on mouse macrophage cell line RAW 264.7 indicate that BP1 enhances the cell proliferation, phagocytosis, nitric oxide production and cytokine secretion in a dose-dependent manner. Because the inhibitor of Toll-like receptor 4 blocks the BP1-induced secretion of TNF-α and IL-6, we hypothesize that α-glucan BP1 activates TLR4, which mediates the above-mentioned immunomodulating effects. PMID:27314319

  3. Structural, chemical and optical evaluation of Cu-doped ZnO nanoparticles synthesized by an aqueous solution method

    Energy Technology Data Exchange (ETDEWEB)

    Iribarren, A., E-mail: augusto@imre.oc.uh.cu [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, Vedado, Plaza, La Habana 10400 (Cuba); Hernández-Rodríguez, E. [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, Vedado, Plaza, La Habana 10400 (Cuba); Maqueira, L. [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, Vedado, Plaza, La Habana 10400 (Cuba); Facultad de Química, Universidad de La Habana, Zapata y G, Vedado, Plaza, La Habana 10400 (Cuba)

    2014-12-15

    Highlights: • Cu-doped ZnO nanoparticles obtained by chemical synthesis. • Substitutional or interstitial Cu into ZnO lead specific structural, chemical, and optical changes. • Incorporation efficiency of Cu atoms in ZnO as a function of the Cu concentration in the precursor dissolution. - Abstract: In this work a study of ZnO and Cu-doped ZnO nanoparticles obtained by chemical synthesis in aqueous media was carried out. Structural analysis gave the dominant presence of wurtzite ZnO phase forming a solid solution Zn{sub 1−x}Cu{sub x}O. For high Cu doping CuO phase is also present. For low Cu concentration the lattice shrinks due to Cu atoms substitute Zn atoms. For high Cu concentration the lattice enlarges due to predominance of interstitial Cu. From elemental analysis we determined and analyzed the incorporation efficiency of Cu atoms in Zn{sub 1−x}Cu{sub x}O as a function of the Cu concentration in the precursor dissolution. Combining structural and chemical results we described the Cu/Zn precursor concentrations r{sub w} in which the solid solution of Cu in ZnO is predominant. In the region located at r{sub w} ≈ 0.2–0.3 it is no longer valid. For Cu/Zn precursor concentration r{sub w} > 0.3 interstitial Cu dominates, and some amount of copper oxide appears. As the Cu concentration increases, the effective size of nanoparticles decreases. Photoluminescence (PL) measurements of the Cu-doped ZnO nanoparticles were carried out and analyzed.

  4. Structural analysis of hierarchically organized zeolites

    Science.gov (United States)

    Mitchell, Sharon; Pinar, Ana B.; Kenvin, Jeffrey; Crivelli, Paolo; Kärger, Jörg; Pérez-Ramírez, Javier

    2015-10-01

    Advances in materials synthesis bring about many opportunities for technological applications, but are often accompanied by unprecedented complexity. This is clearly illustrated by the case of hierarchically organized zeolite catalysts, a class of crystalline microporous solids that has been revolutionized by the engineering of multilevel pore architectures, which combine unique chemical functionality with efficient molecular transport. Three key attributes, the crystal, the pore and the active site structure, can be expected to dominate the design process. This review examines the adequacy of the palette of techniques applied to characterize these distinguishing features and their catalytic impact.

  5. Tunnel Probabilistic Structural Analysis Using the FORM

    OpenAIRE

    Yousef Mirzaeian; Kourosh Shahriar; Mostafa Sharifzadeh

    2015-01-01

    In this paper tunnel probabilistic structural analysis (TuPSA) was performed using the first order reliability method (FORM). In TuPSA, a tunnel performance function is defined according to the boundary between the structural stability and instability. Then the performance function is transformed from original space into the standard normal variable space to obtain the design point, reliability index, and also the probability of tunnel failure. In this method, it is possible to consider the d...

  6. Numerical analysis of shell and spatial structures

    OpenAIRE

    Samartín, Avelino

    1991-01-01

    Since the advent of the computer into the engineering field, the application of the numerical methods to the solution of engineering problems has grown very rapidly. Among the different computer methods of structural analysis the Finite Element (FEM) has been predominantly used. Shells and space structures are very attractive and have been constructed to solve a large variety of functional problems (roofs, industrial building, aqueducts, reservoirs, footings etc). In this type of structu...

  7. PPM-One: a static protein structure based chemical shift predictor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dawei; Brüschweiler, Rafael, E-mail: bruschweiler.1@osu.edu [The Ohio State University, Campus Chemical Instrument Center (United States)

    2015-07-15

    We mined the most recent editions of the BioMagResDataBank and the protein data bank to parametrize a new empirical knowledge-based chemical shift predictor of protein backbone atoms using either a linear or an artificial neural network model. The resulting chemical shift predictor PPM-One accepts a single static 3D structure as input and emulates the effect of local protein dynamics via interatomic steric contacts. Furthermore, the chemical shift prediction was extended to most side-chain protons and it is found that the prediction accuracy is at a level allowing an independent assessment of stereospecific assignments. For a previously established set of test proteins some overall improvement was achieved over current top-performing chemical shift prediction programs.

  8. Chemical structure and pharmacokinetics of novel quinolone agents represented by avarofloxacin, delafloxacin, finafloxacin, zabofloxacin and nemonoxacin

    OpenAIRE

    Kocsis, Bela; Domokos, J.; Szabo, D.

    2016-01-01

    Quinolones are potent antimicrobial agents with a basic chemical structure of bicyclic ring. Fluorine atom at position C-6 and various substitutions on the basic quinolone structure yielded fluoroquinolones, namely norfloxacin, ciprofloxacin, levofloxacin, moxifloxacin and numerous other agents. The target molecules of quinolones and fluoroquinolones are bacterial gyrase and topoisomerase IV enzymes. Broad-spectrum and excellent tissue penetration make fluoroquinolones potent agents but their...

  9. Chemical and Structural Stability of Lithium-Ion Battery Electrode Materials under Electron Beam

    OpenAIRE

    Feng Lin; Isaac M. Markus; Doeff, Marca M.; Xin, Huolin L.

    2014-01-01

    The investigation of chemical and structural dynamics in battery materials is essential to elucidation of structure-property relationships for rational design of advanced battery materials. Spatially resolved techniques, such as scanning/transmission electron microscopy (S/TEM), are widely applied to address this challenge. However, battery materials are susceptible to electron beam damage, complicating the data interpretation. In this study, we demonstrate that, under electron beam irradiati...

  10. Data structures and algorithm analysis in Java

    CERN Document Server

    Shaffer, Clifford A

    2011-01-01

    With its focus on creating efficient data structures and algorithms, this comprehensive text helps readers understand how to select or design the tools that will best solve specific problems. It uses Java as the programming language and is suitable for second-year data structure courses and computer science courses in algorithm analysis. Techniques for representing data are presented within the context of assessing costs and benefits, promoting an understanding of the principles of algorithm analysis and the effects of a chosen physical medium. The text also explores tradeoff issues, familiari

  11. Data structures and algorithm analysis in C++

    CERN Document Server

    Shaffer, Clifford A

    2011-01-01

    With its focus on creating efficient data structures and algorithms, this comprehensive text helps readers understand how to select or design the tools that will best solve specific problems. It uses Microsoft C++ as the programming language and is suitable for second-year data structure courses and computer science courses in algorithm analysis.Techniques for representing data are presented within the context of assessing costs and benefits, promoting an understanding of the principles of algorithm analysis and the effects of a chosen physical medium. The text also explores tradeoff issues, f

  12. Geographical data structures supporting regional analysis

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, R.G.; Durfee, R.C.

    1978-01-01

    In recent years the computer has become a valuable aid in solving regional environmental problems. Over a hundred different geographic information systems have been developed to digitize, store, analyze, and display spatially distributed data. One important aspect of these systems is the data structure (e.g. grids, polygons, segments) used to model the environment being studied. This paper presents eight common geographic data structures and their use in studies of coal resources, power plant siting, population distributions, LANDSAT imagery analysis, and landuse analysis.

  13. Electrical conductivity as a constraint on lower mantle thermo-chemical structure

    Science.gov (United States)

    Deschamps, Frédéric; Khan, Amir

    2016-09-01

    Electrical conductivity of the Earth's mantle depends on both temperature and compositional parameters. Radial and lateral variations in conductivity are thus potentially a powerful means to investigate its thermo-chemical structure. Here, we use available electrical conductivity data for the major lower mantle minerals, bridgmanite and ferropericlase, to calculate 3D maps of lower mantle electrical conductivity for two possible models: a purely thermal model, and a thermo-chemical model. Both models derive from probabilistic seismic tomography, and the thermo-chemical model includes, in addition to temperature anomalies, variations in volume fraction of bridgmanite and iron content. The electrical conductivity maps predicted by these two models are clearly different. Compared to the purely thermal model, the thermo-chemical model leads to higher electrical conductivity, by about a factor 2.5, and stronger lateral anomalies. In the lowermost mantle (2000-2891 km) the thermo-chemical model results in a belt of high conductivity around the equator, whose maximum value reaches ∼120% of the laterally-averaged value and is located in the low shear-wave velocity provinces imaged in tomographic models. Based on our electrical conductivity maps, we computed electromagnetic response functions (C-responses) and found, again, strong differences between the C-responses for purely thermal and thermo-chemical models. At periods of 1 year and longer, C-responses based on thermal and thermo-chemical models are easily distinguishable. Furthermore, C-responses for thermo-chemical model vary geographically. Our results therefore show that long-period (1 year and more) variations of the magnetic field may provide key insights on the nature and structure of the deep mantle.

  14. Nonradiological chemical pathway analysis and identification of chemicals of concern for environmental monitoring at the Hanford Site

    International Nuclear Information System (INIS)

    Pacific Northwest's Surface Environmental Surveillance Project (SESP) is an ongoing effort tot design, review, and conducted monitoring on and off the Hanford site. Chemicals of concern that were selected are listed. Using modeled exposure pathways, the offsite cancer incidence and hazard quotient were calculated and a retrospective pathway analysis performed to estimate what onsite concentrations would be required in the soil for each chemical of concern and other detected chemicals that would be required to obtain an estimated offsite human-health risk of 1.0E-06 cancer incidence or 1.0 hazard quotient. This analysis indicates that current nonradiological chemical contamination occurring on the site does not pose a significant offsite human-health risk; the highest cancer incidence to the offsite maximally exposed individual was from arsenic (1.76E-10); the highest hazard quotient was chromium(VI) (1.48E-04). The most sensitive pathways of exposure were surfacewater and aquatic food consumption. Combined total offsite excess cancer incidence was 2.09E-10 and estimated hazard quotient was 2.40E-04. Of the 17 identified chemicals of concern, the SESP does not currently (routinely) monitor arsenic, benzo(a)pyrene, bis(2- ethylhexyl)phthalate (BEHP), and chrysene. Only 3 of the chemicals of concern (arsenic, BEHP, chloroform) could actually occur in onsite soil at concern high enough to cause a 1.0E-06 excess cancer incidence or a 1.0 hazard index for a given offsite exposure pathway. During the retrospective analysis, 20 other chemicals were also evaluated; only vinyl chloride and thallium could reach targeted offsite risk values

  15. Protein structure similarity clustering (PSSC) and natural product structure as inspiration sources for drug development and chemical genomics.

    Science.gov (United States)

    Dekker, Frank J; Koch, Marcus A; Waldmann, Herbert

    2005-06-01

    Finding small molecules that modulate protein function is of primary importance in drug development and in the emerging field of chemical genomics. To facilitate the identification of such molecules, we developed a novel strategy making use of structural conservatism found in protein domain architecture and natural product inspired compound library design. Domains and proteins identified as being structurally similar in their ligand-sensing cores are grouped in a protein structure similarity cluster (PSSC). Natural products can be considered as evolutionary pre-validated ligands for multiple proteins and therefore natural products that are known to interact with one of the PSSC member proteins are selected as guiding structures for compound library synthesis. Application of this novel strategy for compound library design provided enhanced hit rates in small compound libraries for structurally similar proteins.

  16. Automated assignment of NMR chemical shifts based on a known structure and 4D spectra.

    Science.gov (United States)

    Trautwein, Matthias; Fredriksson, Kai; Möller, Heiko M; Exner, Thomas E

    2016-08-01

    Apart from their central role during 3D structure determination of proteins the backbone chemical shift assignment is the basis for a number of applications, like chemical shift perturbation mapping and studies on the dynamics of proteins. This assignment is not a trivial task even if a 3D protein structure is known and needs almost as much effort as the assignment for structure prediction if performed manually. We present here a new algorithm based solely on 4D [(1)H,(15)N]-HSQC-NOESY-[(1)H,(15)N]-HSQC spectra which is able to assign a large percentage of chemical shifts (73-82 %) unambiguously, demonstrated with proteins up to a size of 250 residues. For the remaining residues, a small number of possible assignments is filtered out. This is done by comparing distances in the 3D structure to restraints obtained from the peak volumes in the 4D spectrum. Using dead-end elimination, assignments are removed in which at least one of the restraints is violated. Including additional information from chemical shift predictions, a complete unambiguous assignment was obtained for Ubiquitin and 95 % of the residues were correctly assigned in the 251 residue-long N-terminal domain of enzyme I. The program including source code is available at https://github.com/thomasexner/4Dassign . PMID:27484442

  17. Protein structure validation and refinement using amide proton chemical shifts derived from quantum mechanics

    DEFF Research Database (Denmark)

    Christensen, Anders Steen; Linnet, Troels Emtekær; Borg, Mikael;

    2013-01-01

    We present the ProCS method for the rapid and accurate prediction of protein backbone amide proton chemical shifts - sensitive probes of the geometry of key hydrogen bonds that determine protein structure. ProCS is parameterized against quantum mechanical (QM) calculations and reproduces high level...

  18. Physico-Chemical and Structural Properties of DeNOx and SO2 Oxidation Catalysts

    DEFF Research Database (Denmark)

    Masters, Stephen Grenville; Oehlers, Cord; Nielsen, Kurt;

    1996-01-01

    Commercial catalysts for NOx removal and SO2 oxidation and their model systems have been investigated by spectroscopic, thermal, electrochemical and X-ray methods. Structural information on the vanadium complexes and compounds as well as physico-chemical properties for catalyst model systems have...... been obtained. The results are discussed in relation to proposed reaction mechanisms....

  19. Incorporating chemical modification constraints into a dynamic programming algorithm for prediction of RNA secondary structure

    Science.gov (United States)

    Mathews, David H.; Disney, Matthew D.; Childs, Jessica L.; Schroeder, Susan J.; Zuker, Michael; Turner, Douglas H.

    2004-01-01

    A dynamic programming algorithm for prediction of RNA secondary structure has been revised to accommodate folding constraints determined by chemical modification and to include free energy increments for coaxial stacking of helices when they are either adjacent or separated by a single mismatch. Furthermore, free energy parameters are revised to account for recent experimental results for terminal mismatches and hairpin, bulge, internal, and multibranch loops. To demonstrate the applicability of this method, in vivo modification was performed on 5S rRNA in both Escherichia coli and Candida albicans with 1-cyclohexyl-3-(2-morpholinoethyl) carbodiimide metho-p-toluene sulfonate, dimethyl sulfate, and kethoxal. The percentage of known base pairs in the predicted structure increased from 26.3% to 86.8% for the E. coli sequence by using modification constraints. For C. albicans, the accuracy remained 87.5% both with and without modification data. On average, for these sequences and a set of 14 sequences with known secondary structure and chemical modification data taken from the literature, accuracy improves from 67% to 76%. This enhancement primarily reflects improvement for three sequences that are predicted with <40% accuracy on the basis of energetics alone. For these sequences, inclusion of chemical modification constraints improves the average accuracy from 28% to 78%. For the 11 sequences with <6% pseudoknotted base pairs, structures predicted with constraints from chemical modification contain on average 84% of known canonical base pairs. PMID:15123812

  20. Using NMR chemical shifts to calculate the propensity for structural order and disorder in proteins

    NARCIS (Netherlands)

    Tamiola, Kamil; Mulder, Frans A. A.

    2012-01-01

    NMR spectroscopy offers the unique possibility to relate the structural propensities of disordered proteins and loop segments of folded peptides to biological function and aggregation behaviour. Backbone chemical shifts are ideally suited for this task, provided that appropriate reference data are a

  1. Structures and Chemical Equilibria of Some N-Heterocycles Containing Amide Linkages

    Directory of Open Access Journals (Sweden)

    N. H. Abd El Moneim

    2003-05-01

    Full Text Available Structures and chemical equilibria of 5-carboxy-2-thiouracil (1, 5,6-diphenyl-3-hydroxy-1,2,4-triazine (2, 1-phenyl-3-methyl-5-pyrazolone (3 and 2-mercapto-4,6-dimethylpyrimidine hydrochloride (4 are reported. Their electronic transitions are assigned and pK values are evaluated and discussed.

  2. RNA Secondary Structure Analysis Using RNAstructure.

    Science.gov (United States)

    Mathews, David H

    2014-06-17

    RNAstructure is a user-friendly program for the prediction and analysis of RNA secondary structure. It is available as a Web server, as a program with a graphical user interface, or as a set of command-line tools. The programs are available for Microsoft Windows, Macintosh OS X, or Linux. This unit provides protocols for RNA secondary structure prediction (using the Web server or the graphical user interface) and prediction of high-affinity oligonucleotide biding sites to a structured RNA target (using the graphical user interface).

  3. MBS Analysis Of Kinetic Structures Using ADAMS

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R.K.

    2009-01-01

    The present paper considers multibody system (MBS) analysis of kinetic structures using the software package ADAMS. Deployable, foldable, expandable and reconfigurable kinetic structures can provide a change in the geometric morphology of the envelope by contributing to making it adaptable to e......-called multibody system (MBS) formalism. The present paper considers MBS modeling of kinetic architectural structures using the software packages ADAMS. As a result, it is found that symbolic MBS simulation tools facilitate a useful evaluation environment for MBS users during a design phase of responsive kinetic...

  4. Two-dimensional dopant analysis in silicon using chemical etching and transmission electron microscopy

    Science.gov (United States)

    Neogi, Suneeta Shamanna

    The purpose of this research has been to develop a methodologoy to map two-dimensional dopant distributions in silicon and investigate the factors that influence the interpretation of the results. The analysis exploits the image contrast obtained by transmission electron microscopy (TEM) using cross-section specimens which have undergone selective chemical etching. The appearance of iso-thickness contours in a selectively etched TEM sample must represent iso-concentration contours when imaged under constant diffraction conditions. The application of this technique is two-fold: (1) to establish a physical metrology of semiconductor devices for the purpose of research and development efforts that impact on future nodes outlined in the semiconductor roadmap and (2) to provide physical data for validation of simulation tools in technology computer aided design (TCAD). The research involves an investigation into the selective removal of doped regions for both test and device structures, followed by an analysis to obtain two-dimensional (2-D) dopant profiles. The critical issues which arise in the development of a methodology to profile dopant distributions and which are addressed in this investigation are, wedge technique versus conventional dimple and ion-mill procedures for thin-film preparation, thin-film versus bulk chemical etching, data acquisition using TEM and choice of diffraction conditions, sensitivity in terms of the etch detection limit, resolution influenced by the effective extinction length of the operating reflection, digital image processing to extract profiles from thickness contours, calibration of the 2-D profiles using a one-dimensional (1-D) calibrator and role of structure/dopant interactions such as stress, interfaces and point defects in test structures and real device structures containing additional processing sequences. Selective chemical etching in combination with TEM has the sensitivity, resolution and reproducibility required to be used

  5. A comparative chemical-structural study of fossil humic acids and those extracted from urban wastes

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, C.; Hernandez, T.; Costa, F.; Ceccanti, B.; Polo, A. (Centro de Edafologia y Biologia Aplicada del Segura, Murcia (Spain))

    1992-05-01

    Chemical-structural features of commercial humic acids (HAs) from leonardite or lignite were studied and the data obtained were compared with those of humic acids extracted from composted urban wastes. The greatest differences showed by the elemental analysis between the three HAs were in N and H contents, both of which diminished with the oxidation degree of the starting materials. FTIR spectra did not show differences between HAs from evolved materials such as leonardite or lignite. However, differences were found between these HAs and those extracted from composts of urban wastes, which showed a greater aliphatic character and a more pronounced peak in the absorption band attributed to secondary amides and in that of carbohydrates. The {sup 13}C-NMR spectra were similar for both HAs from leonardite regardless of their oxidation degree. The percentage of aromaticity of these HAs was 45%. The spectra of compost HAs showed a low aromaticity degree for these HAs as a consequence of the pronounced peak appearing at 73 ppm corresponding to carbon of carbohydrates and/or polyalcohols and aminoacids. Py-GC revealed a high content of benzene and toluene in all the commercial HAs. The values of these fragments as well as those of the ratios between pyrolitic fragments, used as humification index for soils, were the highest in the HA extracted from the more oxidized leonardite. 17 refs., 1 fig., 5 tabs.

  6. Structural and chemical characterization of hardwood from tree species with applications as bioenergy feedstocks.

    Science.gov (United States)

    Cetinkol, Özgül Persil; Smith-Moritz, Andreia M; Cheng, Gang; Lao, Jeemeng; George, Anthe; Hong, Kunlun; Henry, Robert; Simmons, Blake A; Heazlewood, Joshua L; Holmes, Bradley M

    2012-01-01

    Eucalypt species are a group of flowering trees widely used in pulp production for paper manufacture. For several decades, the wood pulp industry has focused research and development efforts on improving yields, growth rates and pulp quality through breeding and the genetic improvement of key tree species. Recently, this focus has shifted from the production of high quality pulps to the investigation of the use of eucalypts as feedstocks for biofuel production. Here the structure and chemical composition of the heartwood and sapwood of Eucalyptus dunnii, E. globulus, E. pillularis, E. urophylla, an E. urophylla-E. grandis cross, Corymbia citriodora ssp. variegata, and Acacia mangium were compared using nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD) and biochemical composition analysis. Some trends relating to these compositions were also identified by Fourier transform near infrared (FT-NIR) spectroscopy. These results will serve as a foundation for a more comprehensive database of wood properties that will help develop criteria for the selection of tree species for use as biorefinery feedstocks. PMID:23300786

  7. Structural and Chemical Characterization of Hardwood from Tree Species with Applications as Bioenergy Feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Çetinkol, Özgül Persil; Smith-Moritz, Andreia M.; Cheng, Gang; Lao, Jeemeng; George, Anthe; Hong, Kunlun; Henry, Robert; Simmons, Blake A.; Heazlewood, Joshua L.; Holmes, Bradley M.; Zabotina, Olga A.

    2012-12-28

    Eucalypt species are a group of flowering trees widely used in pulp production for paper manufacture. For several decades, the wood pulp industry has focused research and development efforts on improving yields, growth rates and pulp quality through breeding and the genetic improvement of key tree species. Recently, this focus has shifted from the production of high quality pulps to the investigation of the use of eucalypts as feedstocks for biofuel production. Here the structure and chemical composition of the heartwood and sapwood of Eucalyptus dunnii, E. globulus, E. pillularis, E. urophylla, an E. urophylla-E. grandis cross, Corymbia citriodora ssp. variegata, and Acacia mangium were compared using nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD) and biochemical composition analysis. Some trends relating to these compositions were also identified by Fourier transform near infrared (FT-NIR) spectroscopy. These results will serve as a foundation for a more comprehensive database of wood properties that will help develop criteria for the selection of tree species for use as biorefinery feedstocks.

  8. Structural Integrity Analysis On Superheater Material Of Plt Surabaya

    International Nuclear Information System (INIS)

    Structural integrity analysis on superheater material of PLTU Suralaya has been carried out. Tested material was carbon steel SA 209 T1A and ferritic steel SA 213 T2 based on data specification from PLTU Suralaya. All stages in analysis include collection of operation history background and material specification, visual examination, radiography testing, chemical composition testing, hardness testing and metallography testing. From analysis and testing results, it is shown that material suffered from decarburization on outside surface (00), hardness decrease and pitting corrosion on 00 surface. Primary cause of pipe failure is decarburization due to carbon element inside material that diffuses from inside to OD surface so that microstructure is only pure ferrite

  9. Fabrication of broadband antireflective black metal surfaces with ultra-light-trapping structures by picosecond laser texturing and chemical fluorination

    Science.gov (United States)

    Zheng, Buxiang; Wang, Wenjun; Jiang, Gedong; Mei, Xuesong

    2016-06-01

    A hybrid method consisting of ultrafast laser-assisted texturing and chemical fluorination treatment was applied for efficiently enhancing the surface broadband antireflection to fabricate black titanium alloy surface with ultra-light-trapping micro-nanostructure. Based on the theoretical analysis of surface antireflective principle of micro-nanostructures and fluoride film, the ultra-light-trapping micro-nanostructures have been processed using a picosecond pulsed ultrafast laser on titanium alloy surfaces. Then fluorination treatment has been performed by using fluoroalkyl silane solution. According to X-ray diffraction phase analysis of the surface compositions and measurement of the surface reflectance using spectrophotometer, the broadband antireflective properties of titanium alloy surface with micro-nano structural characteristics were investigated before and after fluorination treatment. The results show that the surface morphology of micro-nanostructures processed by picosecond laser has significant effects on the antireflection of light waves to reduce the surface reflectance, which can be further reduced using chemical fluorination treatment. The high antireflection of over 98 % in a broad spectral range from ultraviolet to infrared on the surface of metal material has been achieved for the surface structures, and the broadband antireflective black metal surfaces with an extremely low reflectance of ultra-light-trapping structures have been obtained in the wavelength range from ultraviolet-visible to near-infrared, middle-wave infrared. The average reflectance of microgroove groups structured surface reaches as low as 2.43 % over a broad wavelength range from 200 to 2600 nm. It indicates that the hybrid method comprising of picosecond laser texturing and chemical fluorination can effectively induce the broadband antireflective black metal surface. This method has a potential application for fabricating antireflective surface used to improve the

  10. Systems Analysis of Protein Fatty Acylation in Herpes Simplex Virus-Infected Cells Using Chemical Proteomics

    Science.gov (United States)

    Serwa, Remigiusz A.; Abaitua, Fernando; Krause, Eberhard; Tate, Edward W.; O’Hare, Peter

    2015-01-01

    Summary Protein fatty acylation regulates diverse aspects of cellular function and organization and plays a key role in host immune responses to infection. Acylation also modulates the function and localization of virus-encoded proteins. Here, we employ chemical proteomics tools, bio-orthogonal probes, and capture reagents to study myristoylation and palmitoylation during infection with herpes simplex virus (HSV). Using in-gel fluorescence imaging and quantitative mass spectrometry, we demonstrate a generalized reduction in myristoylation of host proteins, whereas palmitoylation of host proteins, including regulators of interferon and tetraspanin family proteins, was selectively repressed. Furthermore, we found that a significant fraction of the viral proteome undergoes palmitoylation; we identified a number of virus membrane glycoproteins, structural proteins, and kinases. Taken together, our results provide broad oversight of protein acylation during HSV infection, a roadmap for similar analysis in other systems, and a resource with which to pursue specific analysis of systems and functions. PMID:26256475

  11. Principal component analysis within nuclear structure

    CERN Document Server

    Al-Sayed, A

    2015-01-01

    The principal component analysis (PCA) of different parameters affecting collectivity of nuclei predicted to be candidate of the interacting boson model dynamical symmetries are performed. The results show that, the use of PCA within nuclear structure can give us a simple way to identify collectivity together with the parameters simultaneously affecting it.

  12. THE GALACTIC STRUCTURE AND CHEMICAL EVOLUTION TRACED BY THE POPULATION OF PLANETARY NEBULAE

    International Nuclear Information System (INIS)

    Planetary nebulae (PNe) derive from the evolution of ∼1-8 Msun mass stars, corresponding to a wide range of progenitor ages, and thus are essential probes of the chemical evolution of galaxies, and indispensable to constrain the results from chemical models. We use an extended and homogeneous data set of Galactic PNe to study the metallicity gradients and the Galactic structure and evolution. The most up-to-date abundances, distances (calibrated with Magellanic Cloud PNe), and other parameters have been employed, together with a novel homogeneous morphological classification, to characterize the different PN populations. We confirm that morphological classes have a strong correlation with Peimbert's type PN, and also with their distribution on the Galactic landscape. We studied the α-element distribution within the Galactic disk, and found that the best selected disk population (i.e., excluding bulge and halo component), together with the most reliable PN distance scale yields to a radial oxygen gradient of Δlog(O/H)/ΔRG = -0.023 ± 0.006 dex kpc-1 for the whole disk sample, and of Δlog(O/H)/ΔRG = -0.035 ± 0.024, -0.023 ± 0.005, and -0.011 ± 0.013 dex kpc-1, respectively for Type I, II, and III PNe, i.e., for high-, intermediate-, and low-mass progenitors. Neon gradients for the same PN types confirm the trend. Accurate statistical analysis shows moderately high uncertainties in the slopes, but also confirms the trend of steeper gradient for PNe with more massive progenitors, indicating a possible steepening with time of the Galactic disk metallicity gradient for what the α-elements are concerned. We found that the metallicity gradients are almost independent on the distance scale model used, as long as these scales are equally well calibrated with the Magellanic Clouds. The PN metallicity gradients presented here are consistent with the local metallicity distribution; furthermore, oxygen gradients determined with young and intermediate age PNe show good

  13. Physico-Chemical Structural and Electrical Studies of Cu-Zn Ferrites Synthesized by Novel Chemical Route

    Science.gov (United States)

    Lohar, K. S.; Patange, S. M.; Mane, D. R.; Shirsath, Sagar E.; Shinde, N. D.; Kulkarni, Nilesh

    The physico-chemical, structural and electrical properties of zinc substituted copper ferrites having the general formula Cu1-xZnxFe2O4 (x=0.0 to x=0.8) have been studied as a function of zinc ion concentration. The sample was prepared by co-precipitation method from corresponding metal sulphates. X-ray diffraction patterns were used to confirm the structure of synthesized samples. The calculated and theoretical values of average lattice constant, tetrahedral bond, tetrahedral edge and unshared octahedral edge were found to increase, while the shared octahedral edge and octahedral bond decrease as the Zn ion concentration increases. The dielectric constant (ε‧) and dielectric loss tangent (tan δ) were measured at a constant frequency 1 kHz as a function of temperature. The dielectric constant and loss tangent were found to increase with rise in temperature. The conduction mechanism in these ferrites is discussed on the basis of electron exchange between Fe2+ and Fe3+ ions. The temperature dependent dc resistivity was carried out in the temperature range 300 to 800 K. The plots of log ρ versus 103/T are linear showing two regions, corresponding to ferrimagnetic and paramagnetic regions.

  14. Biosynthesis, Chemical Structure, and Structure-Activity Relationship of Orfamide Lipopeptides Produced by Pseudomonas protegens and Related Species

    OpenAIRE

    Ma, Zongwang; Geudens, Niels; Kieu, Nam P.; Sinnaeve, Davy; Ongena, Marc; Martins, José C.; Höfte, Monica

    2016-01-01

    Orfamide type cyclic lipopeptides (CLPs) are biosurfactants produced by Pseudomonas and involved in lysis of oomycete zoospores, biocontrol of Rhizoctonia and insecticidal activity against aphids. In this study, we compared the biosynthesis, structural diversity, in vitro and in planta activities of orfamides produced by rhizosphere-derived Pseudomonas protegens and related Pseudornonas species. Genetic characterization together with chemical identification revealed that the main orfamide com...

  15. A Dynamic Model for Energy Structure Analysis

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Energy structure is a complicated system concerning economic development, natural resources, technological innovation, ecological balance, social progress and many other elements. It is not easy to explain clearly the developmental mechanism of an energy system and the mutual relations between the energy system and its related environments by the traditional methods. It is necessary to develop a suitable dynamic model, which can reflect the dynamic characteristics and the mutual relations of the energy system and its related environments. In this paper, the historical development of China's energy structure was analyzed. A new quantitative analysis model was developed based on system dynamics principles through analysis of energy resources, and the production and consumption of energy in China and comparison with the world. Finally, this model was used to predict China's future energy structures under different conditions.

  16. Structural Analysis of Molecular Clouds: Dendrograms

    CERN Document Server

    Rosolowsky, E W; Kauffmann, J; Goodman, A A

    2008-01-01

    We demonstrate the utility of dendrograms at representing the essential features of the hierarchical structure of the isosurfaces for molecular line data cubes. The dendrogram of a data cube is an abstraction of the changing topology of the isosurfaces as a function of contour level. The ability to track hierarchical structure over a range of scales makes this analysis philosophically different from local segmentation algorithms like CLUMPFIND. Points in the dendrogram structure correspond to specific volumes in data cubes defined by their bounding isosurfaces. We further refine the technique by measuring the properties associated with each isosurface in the analysis allowing for a multiscale calculation of molecular gas properties. Using COMPLETE 13CO(1-0) data from the L1448 region in Perseus and mock observations of a simulated data cube, we identify regions that have a significant contribution by self-gravity to their energetics on a range of scales. We find evidence for self-gravitation on all spatial sc...

  17. Chemical structure and pharmacokinetics of novel quinolone agents represented by avarofloxacin, delafloxacin, finafloxacin, zabofloxacin and nemonoxacin.

    Science.gov (United States)

    Kocsis, Bela; Domokos, J; Szabo, D

    2016-01-01

    Quinolones are potent antimicrobial agents with a basic chemical structure of bicyclic ring. Fluorine atom at position C-6 and various substitutions on the basic quinolone structure yielded fluoroquinolones, namely norfloxacin, ciprofloxacin, levofloxacin, moxifloxacin and numerous other agents. The target molecules of quinolones and fluoroquinolones are bacterial gyrase and topoisomerase IV enzymes. Broad-spectrum and excellent tissue penetration make fluoroquinolones potent agents but their toxic side effects and increasing number of resistant pathogens set limits on their use. This review focuses on recent advances concerning quinolones and fluoroquinolones, we will be summarising chemical structure, mode of action, pharmacokinetic properties and toxicity. We will be describing fluoroquinolones introduced in clinical trials, namely avarofloxacin, delafloxacin, finafloxacin, zabofloxacin and non-fluorinated nemonoxacin. These agents have been proved to have enhanced antibacterial effect even against ciprofloxacin resistant pathogens, and found to be well tolerated in both oral and parenteral administrations. These features are going to make them potential antimicrobial agents in the future. PMID:27215369

  18. Nonlinear finite element analysis of concrete structures

    International Nuclear Information System (INIS)

    This report deals with nonlinear finite element analysis of concrete structures loaded in the short-term up until failure. A profound discussion of constitutive modelling on concrete is performed; a model, applicable for general stress states, is described and its predictions are compared with experimental data. This model is implemented in the AXIPLANE-program applicable for axisymmetrick and plane structures. The theoretical basis for this program is given. Using the AXIPLANE-program various concrete structures are analysed up until failure and compared with experimental evidence. These analyses include panels pressure vessel, beams failing in shear and finally a specific pull-out test, the Lok-Test, is considered. In these analyses, the influence of different failure criteria, aggregate interlock, dowel action, secondary cracking, magnitude of compressive strenght, magnitude of tensile strenght and of different post-failure behaviours of the concrete are evaluated. Moreover, it is shown that a suitable analysis of the theoretical data results in a clear insight into the physical behaviour of the considered structures. Finally, it is demonstrated that the AXISPLANE-program for widely different structures exhibiting very delicate structural aspects gives predictions that are in close agreement with experimental evidence. (author)

  19. RNA structural analysis by evolving SHAPE chemistry.

    Science.gov (United States)

    Spitale, Robert C; Flynn, Ryan A; Torre, Eduardo A; Kool, Eric T; Chang, Howard Y

    2014-01-01

    RNA is central to the flow of biological information. From transcription to splicing, RNA localization, translation, and decay, RNA is intimately involved in regulating every step of the gene expression program, and is thus essential for health and understanding disease. RNA has the unique ability to base-pair with itself and other nucleic acids to form complex structures. Hence the information content in RNA is not simply its linear sequence of bases, but is also encoded in complex folding of RNA molecules. A general chemical functionality that all RNAs have is a 2'-hydroxyl group in the ribose ring, and the reactivity of the 2'-hydroxyl in RNA is gated by local nucleotide flexibility. In other words, the 2'-hydroxyl is reactive at single-stranded and conformationally flexible positions but is unreactive at nucleotides constrained by base-pairing. Recent efforts have been focused on developing reagents that modify RNA as a function of RNA 2' hydroxyl group reactivity. Such RNA structure probing techniques can be read out by primer extension in experiments termed RNA SHAPE (selective 2'- hydroxyl acylation and primer extension). Herein, we describe the efforts devoted to the design and utilization of SHAPE probes for characterizing RNA structure. We also describe current technological advances that are being applied to utilize SHAPE chemistry with deep sequencing to probe many RNAs in parallel. The merging of chemistry with genomics is sure to open the door to genome-wide exploration of RNA structure and function.

  20. Nanostructured PLD-grown gadolinia doped ceria: Chemical and structural characterization by transmission electron microscopy techniques

    DEFF Research Database (Denmark)

    Rodrigo, Katarzyna Agnieszka; Wang, Hsiang-Jen; Heiroth, Sebastian;

    2011-01-01

    The morphology as well as the spatially resolved elemental and chemical characterization of 10 mol% gadolinia doped ceria (CGO10) structures prepared by pulsed laser deposition (PLD) technique are investigated by scanning transmission electron microscopy accompanied with electron energy loss...... spectroscopy and energy dispersive X-ray spectroscopy. A dense, columnar and structurally inhomogeneous CGO10 film, i.e. exhibiting grain size refinement across the film thickness, is obtained in the deposition process. The cerium M4,5 edges, used to monitor the local electronic structure of the grains...

  1. Molecular design chemical structure generation from the properties of pure organic compounds

    CERN Document Server

    Horvath, AL

    1992-01-01

    This book is a systematic presentation of the methods that have been developed for the interpretation of molecular modeling to the design of new chemicals. The main feature of the compilation is the co-ordination of the various scientific disciplines required for the generation of new compounds. The five chapters deal with such areas as structure and properties of organic compounds, relationships between structure and properties, and models for structure generation. The subject is covered in sufficient depth to provide readers with the necessary background to understand the modeling

  2. Shape analysis of simulated breast anatomical structures

    Science.gov (United States)

    Contijoch, Francisco; Lynch, Jennifer M.; Pokrajac, David D.; Maidment, Andrew D. A.; Bakic, Predrag R.

    2012-03-01

    Recent advances in high-resolution 3D breast imaging, namely, digital breast tomosynthesis and dedicated breast CT, have enabled detailed analysis of the shape and distribution of anatomical structures in the breast. Such analysis is critically important, since the projections of breast anatomical structures make up the parenchymal pattern in clinical images which can mask the existing abnormalities or introduce false alarms; the parenchymal pattern is also correlated with the risk of cancer. As a first step towards the shape analysis of anatomical structures in the breast, we have analyzed an anthropomorphic software breast phantom. The phantom generation is based upon the recursive splitting of the phantom volume using octrees, which produces irregularly shaped tissue compartments, qualitatively mimicking the breast anatomy. The shape analysis was performed by fitting ellipsoids to the simulated tissue compartments. The ellipsoidal semi-axes were calculated by matching the moments of inertia of each individual compartment and of an ellipsoid. The distribution of Dice coefficients, measuring volumetric overlap between the compartment and the corresponding ellipsoid, as well as the distribution of aspect ratios, measuring relative orientations of the ellipsoids, were used to characterize various classes of phantoms with qualitatively distinctive appearance. A comparison between input parameters for phantom generation and the properties of fitted ellipsoids indicated the high level of user control in the design of software breast phantoms. The proposed shape analysis could be extended to clinical breast images, and used to inform the selection of simulation parameters for improved realism.

  3. [Chemical structure and immunobiological activities of peptidoglycan isolated from Capnocytophaga species].

    Science.gov (United States)

    Hanagata, T

    1990-12-01

    The chemical structure and immunobiological activities of the cell wall peptidoglycan isolated from Capnocytophaga species was investigated. Peptidoglycan was isolated from Capnocytophaga species strain SE2-2 by boiling in 4% sodium dodecyl sulfate and by digestion with pronase, trypsin and alpha-amylase. Analysis of amino acids and amino sugars of the peptidoglycan revealed that glucosamine, muramic acid, D-glutamic acid, alanine, and diaminopimelic acid (A2pm) were the principal components. Serine and glycine were not found. Dinitrophenylation method revealed that about half of A2pm residue had a free amino group, and analysis by hydrazinolysis showed that a small part of alanine and A2pm located at the C-terminal. The above results indicate that one of the amino groups of A2pm residue at one strand of the stem peptide subunit cross-linked to the carboxyl group of alanine of the neighboring strand. It was thus revealed that the peptidoglycan of Capnocytophaga species belonged to the Al gamma type of the classification by Schleifer and Kandler. Peptidoglycan isolated from Capnocytophaga species strain SE2-2 was found to be definitely adjuvant-active in induction of delayed type hypersensitivity against ovalbumin when administered to guinea pigs as water-in-oil emulsion and in stimulation of increase serum antibody levels. Regarding mitogenicity on splenocytes of BALB/c and BALB/c nu/nu mice, peptidoglycan from Capnocytophaga species was markedly enhanced the uptake [3H] thymidine in dose of 10 micrograms/10(5) cells, however thymocytes were not reactive. Stimulation effects on peritoneal macrophages from a guinea pig to incorporation of 14C-glucosamin was exhibited by addition of 100 micrograms of this peptidoglycan. These findings indicate that peptidoglycan of Capnocytophaga species might eventually be responsible for destruction of periodontal tissue by host mediated activities.

  4. Meta-Analysis of the Chemical and Non-Chemical Stressors Affecting Childhood Obesity?

    Science.gov (United States)

    Background: Worldwide, approximately 42 million children under the age of 5 years are considered overweight or obese. While much research has focused on individual behaviors impacting obesity, little research has emphasized the complex interactions of numerous chemical and non-ch...

  5. Identification of Lilial as a fragrance sensitizer in a perfume by bioassay-guided chemical fractionation and structure-activity relationships

    DEFF Research Database (Denmark)

    Arnau, E G; Andersen, Klaus Ejner; Bruze, M;

    2000-01-01

    Fragrance materials are among the most common causes of allergic contact dermatitis. The aim of this study was to identify in a perfume fragrance allergens not included in the fragrance mix, by use of bioassay-guided chemical fractionation and chemical analysis/structure-activity relationships...... (SARs). The basis for the investigation was a 45-year-old woman allergic to her own perfume. She had a negative patch test to the fragrance mix and agreed to participate in the study. Chemical fractionation of the perfume concentrate was used for repeated patch testing and/or repeated open application...

  6. Economic Evaluation of Computerized Structural Analysis

    Science.gov (United States)

    Fortin, P. E.

    1985-01-01

    This completed effort involved a technical and economic study of the capabilities of computer programs in the area of structural analysis. The applicability of the programs to NASA projects and to other users was studied. The applications in other industries was explored including both research and development and applied areas. The costs of several alternative analysis programs were compared. A literature search covered applicable technical literature including journals, trade publications and books. In addition to the literature search, several commercial companies that have developed computerized structural analysis programs were contacted and their technical brochures reviewed. These programs include SDRC I-DEAS, MSC/NASTRAN, SCADA, SUPERSAP, NISA/DISPLAY, STAAD-III, MICAS, GTSTRUDL, and STARS. These programs were briefly reviewed as applicable to NASA projects.

  7. Numerical Limit Analysis of Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Larsen, Kasper Paaske

    For more than half a century, limit state analysis based on the extremum principles have been used to assess the load bearing capacity of reinforced concrete structures. Extensi- ve research within the field has lead to several techniques for performing such analysis manually. While these manual...... limit state analysis problems. The work focuses on determination of the load bearing capacity of reinforced concrete structures by employing the lower bound theorem and a finite element method using equilibrium elements is developed. The recent year’s development within the field of convex optimization...... is applied to solve the limit state problems. Three different element types have been developed and tested. The first is a solid tetra- hedral element with a linear stress distribution. The tri-axial stress state in the element is decomposed into concrete and reinforcement stresses, to which separate yield...

  8. Chemical structure of vanadium-based contact formation on n-AlN

    International Nuclear Information System (INIS)

    We have investigated the chemical interaction between a Au/V/Al/V layer structure and n-type AlN epilayers using soft x-ray photoemission, x-ray emission spectroscopy, and atomic force microscopy. To understand the complex processes involved in this multicomponent system, we have studied the interface before and after a rapid thermal annealing step. We find the formation of a number of chemical phases at the interface, including VN, metallic vanadium, aluminum oxide, and metallic gold. An interaction mechanism for metal contact formation on the entire n-(Al,Ga)N system is proposed.

  9. Structural changes in amorphous organic compounds and their role during chemical transformations

    International Nuclear Information System (INIS)

    Using butanediol vinylacetate and dimetacrylate as an example, it can be shown that structural changes of amorphous-liquid substance play an important part at chemical transformations of amorphous compounds and chemical reaction rate provides an function of local order. When the amorphous polymer is viewed as an system of multiple transformations, each gives birth to the definite local order, the calculation of recombination reaction of active centers accumulated during irradiation of polymer at 77 K is carried out. Concentration of recombinated centers rises steeply near each transformation Tk

  10. Chemical structures of constituents from the whole plant of Bacopa monniera.

    Science.gov (United States)

    Ohta, Tomoe; Nakamura, Seikou; Nakashima, Souichi; Oda, Yoshimi; Matsumoto, Takahiro; Fukaya, Masashi; Yano, Mamiko; Yoshikawa, Masayuki; Matsuda, Hisashi

    2016-07-01

    Two new dammarane-type triterpene oligoglycosides, bacomosaponins A and B, and three new phenylethanoid glycosides, bacomosides A, B1, and B2, were isolated from the whole plant of Bacopa monniera Wettst. The chemical structures of the new constituents were characterized on the basis of chemical and physicochemical evidence. In the present study, bacomosaponins A and B with acyl groups were obtained from the whole plant of B. monniera. This is the first report of acylated dammarane-type triterpene oligoglycosides isolated from B. monniera. In addition, dammarane-type triterpene saponins significantly inhibited the aggregation of 42-mer amyloid β-protein.

  11. Chemical structure of vanadium-based contact formation on n-AlN

    Energy Technology Data Exchange (ETDEWEB)

    Pookpanratana, S.; France, R.; Blum, M.; Bell, A.; Bar, M.; Weinhardt, L.; Zhang, Y.; Hofmann, T.; Fuchs, O.; Yang, W.; Denlinger, J. D.; Mulcahy, S.; Moustakas, T. D.; Heske, Clemens

    2010-05-17

    We have investigated the chemical interaction between a Au/V/Al/V layer structure and n-type AlN epilayers using soft x-ray photoemission, x-ray emission spectroscopy, and atomic force microscopy. To understand the complex processes involved in this multicomponent system, we have studied the interface before and after a rapid thermal annealing step. We find the formation of a number of chemical phases at the interface, including VN, metallic vanadium, aluminum oxide, and metallic gold. An interaction mechanism for metal contact formation on the entire n-(Al,Ga)N system is proposed.

  12. SOIL QUALITY ASSESSMENT BASED ON CHEMICAL, ENZYMATIC AND BACTERIOLOGICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Sofia-Paulina BALAURE

    2012-01-01

    Full Text Available This study highlights the problem of soil pollution as the result of human activities. Soil pollutans may be either chemicals or biological in nature. microbial enzymatic activities are often proposed as indicators of environmental stress. The soil samples were submitted by chemical, microbiological and enzymatic analyses. Chemical analyses were been made for determinating the heavy metals. Heavy metals from the forest soil were represented by Cu, Zn, Mn, Ni, Pb, Cd and Cr. To evaluate the concentration in heavy metals from the filtrate, we used a acetylene-nitrous oxide flame atomic absorption spectrophotometry. Potential dehydrogenase activity, the only indicator of the possible sources of pollution, excluded the presence of either chemical or biological pollution. The number of bacteria involved in the biogeochemical cycle of nitrogen in the analyzed soil indicated a high efficiency regarding the mineralization of the organic residues of plant and animal origin.

  13. Disclosure of hydraulic fracturing fluid chemical additives: analysis of regulations.

    Science.gov (United States)

    Maule, Alexis L; Makey, Colleen M; Benson, Eugene B; Burrows, Isaac J; Scammell, Madeleine K

    2013-01-01

    Hydraulic fracturing is used to extract natural gas from shale formations. The process involves injecting into the ground fracturing fluids that contain thousands of gallons of chemical additives. Companies are not mandated by federal regulations to disclose the identities or quantities of chemicals used during hydraulic fracturing operations on private or public lands. States have begun to regulate hydraulic fracturing fluids by mandating chemical disclosure. These laws have shortcomings including nondisclosure of proprietary or "trade secret" mixtures, insufficient penalties for reporting inaccurate or incomplete information, and timelines that allow for after-the-fact reporting. These limitations leave lawmakers, regulators, public safety officers, and the public uninformed and ill-prepared to anticipate and respond to possible environmental and human health hazards associated with hydraulic fracturing fluids. We explore hydraulic fracturing exemptions from federal regulations, as well as current and future efforts to mandate chemical disclosure at the federal and state level.

  14. 40 CFR 761.292 - Chemical extraction and analysis of individual samples and composite samples.

    Science.gov (United States)

    2010-07-01

    ....61(a)(6) § 761.292 Chemical extraction and analysis of individual samples and composite samples. Use... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Chemical extraction and analysis of individual samples and composite samples. 761.292 Section 761.292 Protection of Environment...

  15. CERENA: ChEmical REaction Network Analyzer--A Toolbox for the Simulation and Analysis of Stochastic Chemical Kinetics.

    Science.gov (United States)

    Kazeroonian, Atefeh; Fröhlich, Fabian; Raue, Andreas; Theis, Fabian J; Hasenauer, Jan

    2016-01-01

    Gene expression, signal transduction and many other cellular processes are subject to stochastic fluctuations. The analysis of these stochastic chemical kinetics is important for understanding cell-to-cell variability and its functional implications, but it is also challenging. A multitude of exact and approximate descriptions of stochastic chemical kinetics have been developed, however, tools to automatically generate the descriptions and compare their accuracy and computational efficiency are missing. In this manuscript we introduced CERENA, a toolbox for the analysis of stochastic chemical kinetics using Approximations of the Chemical Master Equation solution statistics. CERENA implements stochastic simulation algorithms and the finite state projection for microscopic descriptions of processes, the system size expansion and moment equations for meso- and macroscopic descriptions, as well as the novel conditional moment equations for a hybrid description. This unique collection of descriptions in a single toolbox facilitates the selection of appropriate modeling approaches. Unlike other software packages, the implementation of CERENA is completely general and allows, e.g., for time-dependent propensities and non-mass action kinetics. By providing SBML import, symbolic model generation and simulation using MEX-files, CERENA is user-friendly and computationally efficient. The availability of forward and adjoint sensitivity analyses allows for further studies such as parameter estimation and uncertainty analysis. The MATLAB code implementing CERENA is freely available from http://cerenadevelopers.github.io/CERENA/.

  16. Modeling the binding affinity of structurally diverse industrial chemicals to carbon using the artificial intelligence approaches.

    Science.gov (United States)

    Gupta, Shikha; Basant, Nikita; Rai, Premanjali; Singh, Kunwar P

    2015-11-01

    Binding affinity of chemical to carbon is an important characteristic as it finds vast industrial applications. Experimental determination of the adsorption capacity of diverse chemicals onto carbon is both time and resource intensive, and development of computational approaches has widely been advocated. In this study, artificial intelligence (AI)-based ten different qualitative and quantitative structure-property relationship (QSPR) models (MLPN, RBFN, PNN/GRNN, CCN, SVM, GEP, GMDH, SDT, DTF, DTB) were established for the prediction of the adsorption capacity of structurally diverse chemicals to activated carbon following the OECD guidelines. Structural diversity of the chemicals and nonlinear dependence in the data were evaluated using the Tanimoto similarity index and Brock-Dechert-Scheinkman statistics. The generalization and prediction abilities of the constructed models were established through rigorous internal and external validation procedures performed employing a wide series of statistical checks. In complete dataset, the qualitative models rendered classification accuracies between 97.04 and 99.93%, while the quantitative models yielded correlation (R(2)) values of 0.877-0.977 between the measured and the predicted endpoint values. The quantitative prediction accuracies for the higher molecular weight (MW) compounds (class 4) were relatively better than those for the low MW compounds. Both in the qualitative and quantitative models, the Polarizability was the most influential descriptor. Structural alerts responsible for the extreme adsorption behavior of the compounds were identified. Higher number of carbon and presence of higher halogens in a molecule rendered higher binding affinity. Proposed QSPR models performed well and outperformed the previous reports. A relatively better performance of the ensemble learning models (DTF, DTB) may be attributed to the strengths of the bagging and boosting algorithms which enhance the predictive accuracies. The

  17. Chemical Analysis of Wastewater from Unconventional Drilling Operations

    OpenAIRE

    Jonathan B. Thacker; Doug D. Carlton; Zacariah L. Hildenbrand; Kadjo, Akinde F.; Schug, Kevin A.

    2015-01-01

    Trillions of liters of wastewater from oil and gas extraction are generated annually in the US. The contribution from unconventional drilling operations (UDO), such as hydraulic fracturing, to this volume will likely continue to increase in the foreseeable future. The chemical content of wastewater from UDO varies with region, operator, and elapsed time after production begins. Detailed chemical analyses may be used to determine its content, select appropriate treatment options, and identify ...

  18. Quantitative assessment of chemical artefacts produced by propionylation of histones prior to mass spectrometry analysis.

    Science.gov (United States)

    Soldi, Monica; Cuomo, Alessandro; Bonaldi, Tiziana

    2016-07-01

    Histone PTMs play a crucial role in regulating chromatin structure and function, with impact on gene expression. MS is nowadays widely applied to study histone PTMs systematically. Because histones are rich in arginine and lysine, classical shot-gun approaches based on trypsin digestion are typically not employed for histone modifications mapping. Instead, different protocols of chemical derivatization of lysines in combination with trypsin have been implemented to obtain "Arg-C like" digestion products that are more suitable for LC-MS/MS analysis. Although widespread, these strategies have been recently described to cause various side reactions that result in chemical modifications prone to be misinterpreted as native histone marks. These artefacts can also interfere with the quantification process, causing errors in histone PTMs profiling. The work of Paternoster V. et al. is a quantitative assessment of methyl-esterification and other side reactions occurring on histones after chemical derivatization of lysines with propionic anhydride [Proteomics 2016, 16, 2059-2063]. The authors estimate the effect of different solvents, incubation times, and pH on the extent of these side reactions. The results collected indicate that the replacement of methanol with isopropanol or ACN not only blocks methyl-esterification, but also significantly reduces other undesired unspecific reactions. Carefully titrating the pH after propionic anhydride addition is another way to keep methyl-esterification under control. Overall, the authors describe a set of experimental conditions that allow reducing the generation of various artefacts during histone propionylation. PMID:27373704

  19. Comparison of the effect of wet and dry torrefaction on chemical structure and pyrolysis behavior of corncobs.

    Science.gov (United States)

    Zheng, Anqing; Zhao, Zengli; Chang, Sheng; Huang, Zhen; Zhao, Kun; Wei, Guoqiang; He, Fang; Li, Haibin

    2015-01-01

    Wet and dry torrefaction of corncobs was conducted in high-pressure reactor and tube-type reactor, respectively. Effect of wet and dry torrefaction on chemical structure and pyrolysis behavior of corncobs was compared. The results showed that hemicellulose could be effectively removed from corncobs by torrefaction. However, dry torrefaction caused severe degradation of cellulose and the cross-linking and charring of corncobs. X-ray diffraction analysis revealed that crystallinity degree of corncobs was evidently enhanced during wet torrefaction, but reduced during dry torrefaction as raising treatment temperature. In thermogravimetric analysis, wet torrefied corncobs produced less carbonaceous residues than raw corncobs, while dry torrefied corncobs gave much more residues owing to increased content of acid insoluble lignin. Pyrolysis-gas chromatography/mass spectroscopy analysis indicated that wet torrefaction significantly promoted levoglucosan yield owing to the removal of alkali metals. Therefore, wet torrefaction can be considered as a more effective pretreatment method for fast pyrolysis of biomass. PMID:25460979

  20. Comparison of the effect of wet and dry torrefaction on chemical structure and pyrolysis behavior of corncobs.

    Science.gov (United States)

    Zheng, Anqing; Zhao, Zengli; Chang, Sheng; Huang, Zhen; Zhao, Kun; Wei, Guoqiang; He, Fang; Li, Haibin

    2015-01-01

    Wet and dry torrefaction of corncobs was conducted in high-pressure reactor and tube-type reactor, respectively. Effect of wet and dry torrefaction on chemical structure and pyrolysis behavior of corncobs was compared. The results showed that hemicellulose could be effectively removed from corncobs by torrefaction. However, dry torrefaction caused severe degradation of cellulose and the cross-linking and charring of corncobs. X-ray diffraction analysis revealed that crystallinity degree of corncobs was evidently enhanced during wet torrefaction, but reduced during dry torrefaction as raising treatment temperature. In thermogravimetric analysis, wet torrefied corncobs produced less carbonaceous residues than raw corncobs, while dry torrefied corncobs gave much more residues owing to increased content of acid insoluble lignin. Pyrolysis-gas chromatography/mass spectroscopy analysis indicated that wet torrefaction significantly promoted levoglucosan yield owing to the removal of alkali metals. Therefore, wet torrefaction can be considered as a more effective pretreatment method for fast pyrolysis of biomass.

  1. China Rubber Chemicals Production and Market Situation Analysis

    Institute of Scientific and Technical Information of China (English)

    Liang Cheng

    2011-01-01

    Because the stimulus driven impact of the rapid growth of tire and other rubber products' output,in recent years,the production and marketing of domestic rubber chemicals appear to increase,and the specific production and marketing conditions are as follows: 1.Rapid Growth of Chemicals Output From 2009 to 2010,in China an upsurge of expanding or building new rubber chemicals equipment was raised.These equipment were planned to be put into production in 2010 with newly increased production capacity of about 120,000 tons,among which there were 40,000 tons antioxidant 4020,50,000tons accelerator M,and about 40,000 tons other Chemicals.In 2010,the total output was 701,000 tons,with year-on-year growth of 17.8% or so.In 2010,the total sales volume of domestic rubber chemicals were 13 billion yuan,and the export volume was about 180,000 tons,basically the same with that in 2009.See the statistics of domestic rubber chemicals output from 2009 to 2010 in Table 1.

  2. Relationship between chemical structure of soil organic matter and intra-aggregate pore structure: evidence from X-ray computed micro-tomography

    Science.gov (United States)

    Kravchenko, Alexandra; Grandy, Stuart A.

    2014-05-01

    Understanding chemical structure of soil organic matter (SOM) and factors that affect it are vital for gaining understanding of mechanisms of C sequestration by soil. Physical protection of C by adsorption to mineral particles and physical disconnection between C sources and microbial decomposers is now regarded as the key component of soil C sequestration. Both of the processes are greatly influenced by micro-scale structure and distribution of soil pores. However, because SOM chemical structure is typically studied in disturbed (ground and sieved) soil samples the experimental evidence of the relationships between soil pore structure and chemical structure of SOM are still scarce. Our study takes advantage of the X-ray computed micro-tomography (µ-CT) tools that enable non-destructive analysis of pore structure in intact soil samples. The objective of this study is to examine the relationship between SOM chemical structure and pore-characteristics in intact soil macro-aggregates from two contrasting long-term land uses. The two studied land use treatments are a conventionally tilled corn-soybean-wheat rotation treatment and a native succession vegetation treatment removed from agricultural use >20 years ago. The study is located in southwest Michigan, USA, on sandy-loam Typic Hapludalfs. For this study we used soil macro-aggregates 4-6 mm in size collected at 0-15 cm depth. The aggregate size was selected so as both to enable high resolution of µ-CT and to provide sufficient amount of soil for C measurements. X-ray µ-CT scanning was conducted at APS Argonne at a scanning resolution of 14 µm. Two scanned aggregates (1 per treatment) were used in this preliminary study. Each aggregate was cut into 7 "geo-referenced" sections. Analyses of pore characteristics in each section were conducted using 3DMA and ImageJ image analysis tools. SOM chemistry was analyzed using pyrolysis/gas chromatography-mass spectroscopy. Results demonstrated that the relationships

  3. Protein structure similarity clustering and natural product structure as guiding principles for chemical genomics.

    Science.gov (United States)

    Koch, M A; Waldmann, H

    2006-01-01

    The majority of all proteins are modularly built from a limited set of approximately 1,000 structural domains. The knowledge of a common protein fold topology in the ligand-sensing cores of protein domains can be exploited for the design of small-molecule libraries in the development of inhibitors and ligands. Thus, a novel strategy of clustering protein domain cores based exclusively on structure similarity considerations (protein structure similarity clustering, PSSC) has been successfully applied to the development of small-molecule inhibitors of acetylcholinesterase and the 11beta-hydroxysteroid dehydrogenases based on the structure of a naturally occurring Cdc25 inhibitor. The efficiency of making use of the scaffolds of natural products as biologically prevalidated starting points for the design of compound libraries is further highlighted by the development of benzopyran-based FXR ligands.

  4. Quantum chemical analysis of binary and ternary ferromagnetic alloys; Quantenchemische Untersuchungen binaerer und ternaerer ferromagnetischer Legierungen

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Yasemin Erika Charlotte

    2007-02-23

    In this work the electronic structures, densities of states, chemical bonding, magnetic exchange Parameters and Curie temperatures of binary and ternary ferromagnetic alloys are analyzed. The electronic structure of ferromagnetic MnAl has been calculated using density-functional techniques (TB-LMTO-ASA, FPLAPW) and quantum chemically analyzed by means of the crystal orbital Hamilton population analysis. The crystal structure of the ferromagnetic tetragonal MnAl may be understood to originate from the structure of nonmagnetic cubic MnAl with a CsCl motif through a two-step process. While the nonmagnetic cubic structure is stable against a structural deformation, antibonding Mn-Mn interactions at the Fermi level lead to spin polarization and the onset of magnetism, i.e., a symmetry reduction taking place solely in the electronic degrees of freedom, by that emptying antibonding Mn-Mn states. Residual antibonding Al--Al states can only be removed by a subsequent, energetically smaller structural deformation towards the tetragonal system. As a final result, homonuclear bonding is strengthened and heteronuclear bonding is weakened. Corresponding DFT calculations of the electronic structure as well as the calculation of the chemical bonding and the magnetic exchange interactions have been performed on the basis of LDA and GGA for a series of ferromagnetic full Heusler alloys of general formula Co2MnZ (Z=Ga,Si,Ge,Sn), Rh2MnZ (Z=Ge,Sn,Pb), Ni2MnZ (Z=Ga,In,Sn), Pd2MnZ (Z=Sn,Sb) and Cu2MnZ (Z=Al,In,Sn). The connection between the electronic spectra and the magnetic interactions have been studied. Correlations between the chemical bondings in Heusler alloys derived from COHP analysis and magnetic phenomena are obvious, and different mechanisms leading to spin polarization and ferromagnetism are derived. The band dependence of the exchange parameters, their dependence on volume and valence electron concentration have been thoroughly analyzed within the Green function technique

  5. Effects of chemical and biological pesticides on plant growth parameters and rhizospheric bacterial community structure in Vigna radiata

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Sunil; Gupta, Rashi; Sharma, Shilpi, E-mail: shilpi@dbeb.iitd.ac.in

    2015-06-30

    Highlights: • Non-target effects of pesticides employing qualitative and quantitative approaches. • Qualitative shifts in resident and active bacterial community structure. • Abundance of 16S rRNA gene and transcripts were reduced significantly. • Effects of biological pesticide similar to chemical pesticides on rhizospheric bacteria. - Abstract: With increasing application of pesticides in agriculture, their non-target effects on soil microbial communities are critical to soil health maintenance. The present study aimed to evaluate the effects of chemical pesticides (chlorpyrifos and cypermethrin) and a biological pesticide (azadirachtin) on growth parameters and the rhizospheric bacterial community of Vigna radiata. Qualitative and quantitative analysis by PCR-denaturing gradient gel electrophoresis (DGGE) and q-PCR, respectively, of the 16S rRNA gene and transcript were performed to study the impact of these pesticides on the resident and active rhizospheric bacterial community. While plant parameters were not affected significantly by the pesticides, a shift in the bacterial community structure was observed with an adverse effect on the abundance of 16S rRNA gene and transcripts. Chlorpyrifos showed almost complete degradation toward the end of the experiment. These non-target impacts on soil ecosystems and the fact that the effects of the biopesticide mimic those of chemical pesticides raise serious concerns regarding their application in agriculture.

  6. Effects of chemical and biological pesticides on plant growth parameters and rhizospheric bacterial community structure in Vigna radiata

    International Nuclear Information System (INIS)

    Highlights: • Non-target effects of pesticides employing qualitative and quantitative approaches. • Qualitative shifts in resident and active bacterial community structure. • Abundance of 16S rRNA gene and transcripts were reduced significantly. • Effects of biological pesticide similar to chemical pesticides on rhizospheric bacteria. - Abstract: With increasing application of pesticides in agriculture, their non-target effects on soil microbial communities are critical to soil health maintenance. The present study aimed to evaluate the effects of chemical pesticides (chlorpyrifos and cypermethrin) and a biological pesticide (azadirachtin) on growth parameters and the rhizospheric bacterial community of Vigna radiata. Qualitative and quantitative analysis by PCR-denaturing gradient gel electrophoresis (DGGE) and q-PCR, respectively, of the 16S rRNA gene and transcript were performed to study the impact of these pesticides on the resident and active rhizospheric bacterial community. While plant parameters were not affected significantly by the pesticides, a shift in the bacterial community structure was observed with an adverse effect on the abundance of 16S rRNA gene and transcripts. Chlorpyrifos showed almost complete degradation toward the end of the experiment. These non-target impacts on soil ecosystems and the fact that the effects of the biopesticide mimic those of chemical pesticides raise serious concerns regarding their application in agriculture

  7. EXPERIMENTAL MODAL ANALYSIS OF VISCO-ELASTICALLY DAMPED STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The form of the modal analysis of viscoelastically damped structures is simplified and this simplified form is similar to the form of the modal analysis of linear viscously damped structures. As a result of this simplified form, the experimental modal analysis methods of linear viscously damped structures are applied to the experimental modal analysis of viscoelastically damped structures.

  8. Guidelines for soil-structure interaction analysis

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, W.S. (International Civil Engineering Consultants, Inc., Berkeley, CA (United States)); Hadjian, A.H. (Bechtel Corp., Los Angeles, CA (United States))

    1991-10-01

    This report presents engineering application guidelines for conducting seismic soil-structure interaction (SSI) analyses of nuclear power plant structures. These guidelines are largely based on the results obtained and lessons learned from the Large-Scale Seismic Test (LSST) program involving {1/4} and 1/12 scaled containment models in Lotung, Taiwan. The development of these guidelines has taken into consideration the guidelines recommended in the ASCE Standard 4--86, Seismic Analysis of Safety-Related Nuclear Structures'', and the new revision (Revision 2) of the NRC Standard Review Plan (SRP), Section 3.7.2, Seismic System Analysis.'' The guidelines presented in this report follow an approach which reckons every necessary step for characterizing and providing an adequate solution to the total SSI problem which is broken down into a series of five SSI subproblems, namely, site response problem, foundation scattering problem, structural modelling problem, foundation impedance problem, and interaction response solution problem. The four analysis methods evaluated are the lumped-parameter (soil-spring) method, the continuum-halfspace substructing (CLASSI) method, the discretized-halfspace substructing (SASSI) method, and the finite element direct (FLUSH and ALUSH) method. The approach used herein was found to be very effective for evaluating the validities of the various SSI analysis results and findings of the LSST program. The guidelines presented herein place emphasis on the general requirements, procedures, and criteria for conducting SSI analyses in an industry environment by those involved in the seismic design or performance evaluation of nuclear power plant structures and equipment. 53 refs., 17 figs.

  9. Guidelines for soil-structure interaction analysis

    International Nuclear Information System (INIS)

    This report presents engineering application guidelines for conducting seismic soil-structure interaction (SSI) analyses of nuclear power plant structures. These guidelines are largely based on the results obtained and lessons learned from the Large-Scale Seismic Test (LSST) program involving 1/4 and 1/12 scaled containment models in Lotung, Taiwan. The development of these guidelines has taken into consideration the guidelines recommended in the ASCE Standard 4--86, ''Seismic Analysis of Safety-Related Nuclear Structures'', and the new revision (Revision 2) of the NRC Standard Review Plan (SRP), Section 3.7.2, ''Seismic System Analysis.'' The guidelines presented in this report follow an approach which reckons every necessary step for characterizing and providing an adequate solution to the total SSI problem which is broken down into a series of five SSI subproblems, namely, site response problem, foundation scattering problem, structural modelling problem, foundation impedance problem, and interaction response solution problem. The four analysis methods evaluated are the lumped-parameter (soil-spring) method, the continuum-halfspace substructing (CLASSI) method, the discretized-halfspace substructing (SASSI) method, and the finite element direct (FLUSH and ALUSH) method. The approach used herein was found to be very effective for evaluating the validities of the various SSI analysis results and findings of the LSST program. The guidelines presented herein place emphasis on the general requirements, procedures, and criteria for conducting SSI analyses in an industry environment by those involved in the seismic design or performance evaluation of nuclear power plant structures and equipment. 53 refs., 17 figs

  10. NMR crystallography of enzyme active sites: probing chemically detailed, three-dimensional structure in tryptophan synthase.

    Science.gov (United States)

    Mueller, Leonard J; Dunn, Michael F

    2013-09-17

    NMR crystallography--the synergistic combination of X-ray diffraction, solid-state NMR spectroscopy, and computational chemistry--offers unprecedented insight into three-dimensional, chemically detailed structure. Initially, researchers used NMR crystallography to refine diffraction data from organic and inorganic solids. Now we are applying this technique to explore active sites in biomolecules, where it reveals chemically rich detail concerning the interactions between enzyme site residues and the reacting substrate. Researchers cannot achieve this level of detail from X-ray, NMR,or computational methodologies in isolation. For example, typical X-ray crystal structures (1.5-2.5 Å resolution) of enzyme-bound intermediates identify possible hydrogen-bonding interactions between site residues and substrate but do not directly identify the protonation states. Solid-state NMR can provide chemical shifts for selected atoms of enzyme-substrate complexes, but without a larger structural framework in which to interpret them only empirical correlations with local chemical structure are possible. Ab initio calculations and molecular mechanics can build models for enzymatic processes, but they rely on researcher-specified chemical details. Together, however, X-ray diffraction, solid-state NMR spectroscopy, and computational chemistry can provide consistent and testable models for structure and function of enzyme active sites: X-ray crystallography provides a coarse framework upon which scientists can develop models of the active site using computational chemistry; they can then distinguish these models by comparing calculated NMR chemical shifts with the results of solid-state NMR spectroscopy experiments. Conceptually, each technique is a puzzle piece offering a generous view of the big picture. Only when correctly pieced together, however, can they reveal the big picture at the highest possible resolution. In this Account, we detail our first steps in the development of

  11. Structural Analysis of a wing box

    Directory of Open Access Journals (Sweden)

    Layston Ferroni Soares,

    2015-05-01

    Full Text Available The structural analysis is an important tool that allows the research for weight reduction, the choose of the best materials and to satisfy specifications and requirements. In an aircraft’s design, several analyzes are made to prove that this aircraft will stand the set of maneuvers that it was designed to accomplish. This work will consider the preliminar project of an aircraft seeking to check the behavior of the wing under certain loading conditions in the flight envelope.To get to this load set, it has been done all the process of specification of an aircraft, such as mission definition, calculation of weight and c.g. envelope, definition of the geometric characteristics of the aircraft, the airfoil choice, preliminary performance equations, aerodynamic coefficients and the aircraft’s balancing for the equilibrium condition, but such things will not be considered in this article. For the structural analysis of the wing will be considered an arbitrary flight condition, disregarding the effect of gusts loads. With the acquisition of the items mentioned, the main forces acting on the wing structure and their equations will be calculated. The use of finite element method will enable the application of loads obtained just as the development of a method of calculation, along with the construction of a three-dimensional model that represents a chosen condition. The results will be discussed in order to explain the influence of the applied loads in the structural behavior of the wing principal structure.

  12. Parallel processing of structural integrity analysis codes

    International Nuclear Information System (INIS)

    Structural integrity analysis forms an important role in assessing and demonstrating the safety of nuclear reactor components. This analysis is performed using analytical tools such as Finite Element Method (FEM) with the help of digital computers. The complexity of the problems involved in nuclear engineering demands high speed computation facilities to obtain solutions in reasonable amount of time. Parallel processing systems such as ANUPAM provide an efficient platform for realising the high speed computation. The development and implementation of software on parallel processing systems is an interesting and challenging task. The data and algorithm structure of the codes plays an important role in exploiting the parallel processing system capabilities. Structural analysis codes based on FEM can be divided into two categories with respect to their implementation on parallel processing systems. The first category codes such as those used for harmonic analysis, mechanistic fuel performance codes need not require the parallelisation of individual modules of the codes. The second category of codes such as conventional FEM codes require parallelisation of individual modules. In this category, parallelisation of equation solution module poses major difficulties. Different solution schemes such as domain decomposition method (DDM), parallel active column solver and substructuring method are currently used on parallel processing systems. Two codes, FAIR and TABS belonging to each of these categories have been implemented on ANUPAM. The implementation details of these codes and the performance of different equation solvers are highlighted. (author). 5 refs., 12 figs., 1 tab

  13. Effect of chemical substituents on the structure of glassy diphenyl polycarbonates.

    Science.gov (United States)

    Sulatha, M S; Natarajan, Upendra

    2011-02-24

    Polycarbonates offer a wide variety of physical property behavior that is difficult to predict due to complexities at the molecular scale. Here, the physical structure of amorphous glassy polycarbonates having aliphatic and cycloaliphatic chemical groups is explored through atomistic simulations. The influence of chemical structure on solubility parameter, torsion distributions, radial distribution function, scattering structure factor, orientation distributions of phenylene rings and carbonate groups, and free volume distributions, leading to interchain packing effects, are shown. The effect of the cyclohexyl ring at the isopropylidene carbon as compared to the effect of the methyl groups positioned on the phenylene rings results in a larger reduction in the solubility parameter (δ). The interchain distance estimated for polycarbonates in this work is in the range of 5-5.8 Å. The o-methyl groups on the phenylene rings, as compared to a cyclohexyl ring, lead to higher interchain distances. The highest interchain distance is observed with a trimethylcyclohexylidene group at the isopropylidene carbon. Atomistic simulations reveal two different types of packing arrangement of nearest-neighbor chains in the glassy state, one type of which agrees with the NMR experimental data. The fundamental insights provided here can be utilized for design of chemical structures for tailored macroscopic properties.

  14. Earle K. Plyler Prize for Molecular Spectroscopy & Dynamics Lecture: Broadband Rotational Spectroscopy for Chemical Kinetics, Molecular Structure, and Analytical Chemistry

    Science.gov (United States)

    Pate, Brooks

    2013-03-01

    Advances in high-speed digital electronics have enabled a new generation of molecular rotational spectroscopy techniques that provide instantaneous broadband spectral coverage. These techniques use a chirped excitation pulse to coherently excite the molecular sample over a spectral bandwidth of 10 GHz or larger through rapid passage. The subsequent time-domain emission is recorded using high-speed digitizers (up to 100 Gigasample/s) and the frequency domain spectrum is produced by fast Fourier transformation. The chirped-pulse Fourier transform (CP-FT) method has been implemented in the microwave frequency range (2-40 GHz) for studies of cold samples in pulsed jet sources and in the mm-wave/terahertz (THz) frequency range for studies of samples at room-temperature. The method has opened new applications for molecular rotational spectroscopy in the area of chemical kinetics where dynamic rotational spectroscopy is used to measure the rates of unimolecular isomerization reactions in highly excited molecules prepared by pulsed infrared laser excitation. In these applications, the isomerization rate is obtained from an analysis of the overall line shapes which are modified by chemical exchange leading to coalescence behavior similar to the effect in NMR spectroscopy. The sensitivity of the method and the ability to extend it to low frequency (2-8 GHz) have significantly increased the size range of molecules and molecular clusters for structure determination using isotopic substitution to build up the 3D molecular structures atom-by-atom. Application to the structure of water clusters with up to 15 water molecules will be presented. When coupled with advances in solid-state mm-wave/THz devices, this method provides a direct digital technique for analytical chemistry of room-temperature gases based on molecular rotational spectroscopy. These high-throughput methods can analyze complex sample mixtures with unmatched chemical selectivity and short analysis times. Work

  15. Development of new materials and structures based on managed physical-chemical factors of local interaction

    Science.gov (United States)

    Urakov, A. L.

    2016-04-01

    The paper states that assigning certain physical and chemical characteristics to pills and medical drugs solutions can substitute for the development of new drugs (which is essentially equivalent to the creation of new medicines). It is established that the purposeful change of physical and chemical characteristics of the standard ("old") materials (in other words, the known substances) is fundamental for the production of solid and liquid medicines, which allows us to get "new" structures and materials. The paper shows that assigning new physical and chemical properties to "old" materials and their further usage for the production of tablets and solutions from the "old" and well-known medicines can turn even very "old" medicine into very "novel" (moreover, even very fashionable) one with unprecedented (fantastic) pharmacological activity and new mechanisms of action.

  16. Morphological, physico-chemical and structural characterization of mucilage isolated from the seeds of Buchanania lanzan Spreng

    Directory of Open Access Journals (Sweden)

    Sudarshan Singh

    2014-01-01

    Full Text Available Context: Mucilage isolated from the seeds of Buchanania lanzan a wild Indian plant. This mucilage can be commercially exploited, by evaluating physico-chemical properties of this mucilage. Materials and Methods: Various physico-chemical parameter using scanning electron microscopy (SEM, molecular weight, X-ray diffraction (XRD spectrometry, zeta potential (ZP, Fourier transform infrared (FT-IR spectroscopy and 1D ( 1 H and 13 C nuclear magnetic resonance (NMR have been employed to characterize mucilage in the present study. Results: SEM analysis suggests that the mucilage has irregular particle size. Thermogravimetry analysis suggested that mucilage had good thermal stability with two stage decomposition. The weight-average molecular weight of mucilage was determined to be 4883, by gel permeation chromatography. The XRD pattern of the mucilage indicated a completely amorphous structure. The ZP was obtained 1.56 and −9.49 mV in water and 0.1 N NaCl respectively. The major functional groups identified from FT-IR spectrum include 3459/cm (-OH, 1667/cm (Alkenyl C-H and C = C stretch, 1407/cm (-COO- and 1321/cm (-CH 3 CO. Analysis of mucilage by paper chromatography and 1D NMR indicated the presence of rhamnose, arabinose and fructose. Conclusion: The spectral and chromatography analysis of mucilage indicate that the mucilage is composed of basic sugar moiety such as (arabinose, rhamnose, fructose and mannose as complex carbohydrates.

  17. Evaluating Chemical Persistence in a Multimedia Environment: ACART Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, D.H.; McKone, T.E.; Kastenberg, W.E.

    1999-02-01

    For the thousands of chemicals continuously released into the environment, it is desirable to make prospective assessments of those likely to be persistent. Persistent chemicals are difficult to remove if adverse health or ecological effects are later discovered. A tiered approach using a classification scheme and a multimedia model for determining persistence is presented. Using specific criteria for persistence, a classification tree is developed to classify a chemical as ''persistent'' or ''non-persistent'' based on the chemical properties. In this approach, the classification is derived from the results of a standardized unit world multimedia model. Thus, the classifications are more robust for multimedia pollutants than classifications using a single medium half-life. The method can be readily implemented and provides insight without requiring extensive and often unavailable data. This method can be used to classify chemicals when only a few properties are known and be used to direct further data collection. Case studies are presented to demonstrate the advantages of the approach.

  18. International Research Project on the Effects of Chemical Ageing of Polymers on Performance Properties: Chemical and Thermal Analysis

    Science.gov (United States)

    Bulluck, J. W.; Rushing, R. A.

    1996-01-01

    Work during the past six months has included significant research in several areas aimed at further clarification of the aging and chemical failure mechanism of thermoplastics (PVDF or Tefzel) pipes. Among the areas investigated were the crystallinity changes associated with both the Coflon and Tefzel after various simulated environmental exposures using X-ray diffraction analysis. We have found that significant changes in polymer crystallinity levels occur as a function of the exposures. These crystallinity changes may have important consequences on the fracture, fatigue, tensile, and chemical resistance of the materials. We have also noted small changes in the molecular weight distribution. Again these changes may result in variations in the mechanical and chemical properties in the material. We conducted numerous analytical studies with methods including X-ray Diffraction, Gel Permeation Chromatography, Fourier Transform Infrared Spectroscopy, Ultra- Violet Scanning Analysis, GC/Mass Spectrometry, Differential Scanning Calorimetry and Thermomechanical Analysis. In the ultra-violet analysis we noted the presence of an absorption band indicative of triene formation. We investigated a number of aged samples of both Tefzel and Coflon that were forwarded from MERL. We also cast films at SWT and subjected these films to a refluxing methanol 1% ethylene diamine solution. An updated literature search was conducted using Dialog and DROLLS to identify any new papers that may have been published in the open literature since the start of this project. The updated literature search and abstracts are contained in the Appendix section of this report.

  19. Matlab Code for Structural Decomposition Analysis

    OpenAIRE

    Juan Tomas Sayago-Gomez

    2014-01-01

    This TechDoc describes the steps necessary to apply the Structural Decomposition Analysis (SDA) using Matlab. The code has two stages. The first stage, which comprises PrepSDA.m and RAS_SDA.m, prepares the data and the input required for SDA based on the accounting identities defined in Miller and Blair (2009) and Jackson and Schwarm (2011). The second stage (SDA.m) carries out the analysis and estimates the results based on the mathematical procedure in Yang and Lahr (2010) and Zhang and Lah...

  20. Chemical Derivatization and Ultrahigh Resolution and Accurate Mass Spectrometry Strategies for "Shotgun" Lipidome Analysis.

    Science.gov (United States)

    Ryan, Eileen; Reid, Gavin E

    2016-09-20

    Lipids play critical structural and functional roles in the regulation of cellular homeostasis, and it is increasingly recognized that the disruption of lipid metabolism or signaling or both is associated with the onset and progression of certain metabolically linked diseases. As a result, the field of lipidomics has emerged to comprehensively identify and structurally characterize the diverse range of lipid species within a sample of interest and to quantitatively monitor their abundances under different physiological or pathological conditions. Mass spectrometry (MS) has become a critical enabling platform technology for lipidomic researchers. However, the presence of isobaric (i.e., same nominal mass) and isomeric (i.e., same exact mass) lipids within complex lipid extracts means that MS-based identification and quantification of individual lipid species remains a significant analytical challenge. Ultrahigh resolution and accurate mass spectrometry (UHRAMS) offers a convenient solution to the isobaric mass overlap problem, while a range of chromatographic separation, differential extraction, intrasource separation and selective ionization methods, or tandem mass spectrometry (MS/MS) strategies may be used to address some types of isomeric mass lipid overlaps. Alternatively, chemical derivatization strategies represent a more recent approach for the separation of lipids within complex mixtures, including for isomeric lipids. In this Account, we highlight the key components of a lipidomics workflow developed in our laboratory, whereby certain lipid classes or subclasses, namely, aminophospholipids and O-alk-1'-enyl (i.e., plasmalogen) ether-containing lipids, are shifted in mass following sequential functional group selective chemical derivatization reactions prior to "shotgun" nano-ESI-UHRAMS analysis, "targeted" MS/MS, and automated database searching. This combined derivatization and UHRAMS approach resolves both isobaric mass lipids and certain categories of

  1. Mechanical Response Analysis of Asphalt Pavement Structure

    Directory of Open Access Journals (Sweden)

    Yu Zhenqing

    2015-11-01

    Full Text Available Generally, the Chinese designed life of the high- grade asphalt concrete pavement is required 15 years, however, the designed life of the road in surface is often lower than the designed life, and even premature failure. Especially in heavy traffic conditions, the early damage of some high grade-asphalt pavement in China is serious. According to some investigations, we founded the main reason of the long-life asphalt pavement is to determine the function of each structure layer. According to the stress of pavement structure layer, so as to select the structure layer materials. Based on the viewpoint of mechanics, asphalt pavement damage mode is divided into three categories, such as top-down crack, fatigue cracking and rutting. Therefore, this paper uses ANSYS finite element software as calculation tool, the combination of road vehicle load and the primary influence on asphalt pavement structure mechanics response characteristics were analyzed. In this paper, the method of analysis is control variable: that means under different vehicle axle load, only change surface layer modulus and observe the pavement structure mechanical response trends to compare the effect. By using the same method, the response of the pavement base course parameters to the pavement mechanical structure is analyzed.

  2. Analysis of forward and inverse problems in chemical dynamics and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rabitz, H. [Princeton Univ., NJ (United States)

    1993-12-01

    The overall scope of this research concerns the development and application of forward and inverse analysis tools for problems in chemical dynamics and chemical kinetics. The chemical dynamics work is specifically associated with relating features in potential surfaces and resultant dynamical behavior. The analogous inverse research aims to provide stable algorithms for extracting potential surfaces from laboratory data. In the case of chemical kinetics, the focus is on the development of systematic means to reduce the complexity of chemical kinetic models. Recent progress in these directions is summarized below.

  3. ANALYSIS OF SOLUBLE CHEMICAL TRANSFER BY RUNOFF WATER IN FIELD

    Institute of Scientific and Technical Information of China (English)

    TONG Ju-xiu; YANG Jin-zhong

    2008-01-01

    In order to determine the main factors influencing soluble chemical transfer and corresponding techniques for reducing fertilizer loss caused by runoff in irrigated fields, a physically based two-layer model was developed with incomplete mixing theory. Different forms of incomplete mixing parameters were introduced in the model, which was successfully verified with previous published experimental data. According to comparison, the chemicals loss of fertilizer is very sensitive to the runoff-related parameter while it is not sensitive to the infiltration-related parameter. The calculated results show that the chemicals in infiltration water play an important role in the early time of rainfall even with saturated soil, and it is mainly in the runoff flow in the late rainfall. Therefore, prevention of shallow subsurface drainage in the early rainfall is an effective way to reduce fertilizer loss, and the coverage on soil surface is another effective way.

  4. Chemical-mechanical stability of the hierarchical structure of shell nacre

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The hierarchical structure and mechanical property of shell nacre are experimentally investigated from the new aspects of chemical stability and chemistry-mechanics coupling. Through chemical deproteinization or demineralization methods together with characterization techniques at micro/nano scales,it is found that the nacre of abalone,haliotis discus hannai,contains a hierarchical structure stacked with irregular aragonite platelets and interplatelet organic matrix thin layers. Yet the aragonite platelet itself is a nanocomposite consisting of nanoparticles and intraplatelet organic matrix framework. The mean diameter of the nanoparticles and the distribution of framework are quite different for different platelets. Though the interplatelet and in-traplatelet organic matrix can be both decomposed by sodium hydroxide solution,the chemical stability of individual aragonite platelets is much higher than that of the microstructure stacked with them. Further,macroscopic bending test or nanoindentation experiment is performed on the micro/nanostructure of nacre after sodium hydroxide treatment. It is found that the Young’s modulus of both the stacked microstructure and nanocomposite platelet reduced. The reduction of the microstructure is more remark than that of the platelet. Therefore the chemical-mechanical stability of the nanocomposite platelet itself is much higher than that of the stacked microstructure of nacre.

  5. Combination of structural reliability and interval analysis

    Institute of Scientific and Technical Information of China (English)

    Zhiping Qiu; Di Yang; saac Elishakoff

    2008-01-01

    In engineering applications,probabilistic reliability theory appears to be presently the most important method,however,in many cases precise probabilistic reliability theory cannot be considered as adequate and credible model of the real state of actual affairs.In this paper,we developed a hybrid of probabilistic and non-probabilistic reliability theory,which describes the structural uncertain parameters as interval variables when statistical data are found insufficient.By using the interval analysis,a new method for calculating the interval of the structural reliability as well as the reliability index is introduced in this paper,and the traditional probabilistic theory is incorporated with the interval analysis.Moreover,the new method preserves the useful part of the traditional probabilistic reliability theory,but removes the restriction of its strict requirement on data acquisition.Example is presented to demonstrate the feasibility and validity of the proposed theory.

  6. Preparedness of emergency departments in northwest England for managing chemical incidents: a structured interview survey

    Directory of Open Access Journals (Sweden)

    Walter Darren

    2007-12-01

    Full Text Available Abstract Background A number of significant chemical incidents occur in the UK each year and may require Emergency Departments (EDs to receive and manage contaminated casualties. Previously UK EDs have been found to be under-prepared for this, but since October 2005 acute hospital Trusts have had a statutory responsibility to maintain decontamination capacity. We aimed to evaluate the level of preparedness of Emergency Departments in North West England for managing chemical incidents. Methods A face-to-face semi-structured interview was carried out with the Nurse Manager or a nominated deputy in all 18 Emergency Departments in the Region. Results 16/18 departments had a written chemical incident plan but only 7 had the plan available at interview. All had a designated decontamination area but only 11 felt that they were adequately equipped. 12/18 had a current training programme for chemical incident management and 3 had no staff trained in decontamination. 13/18 could contain contaminated water from casualty decontamination and 6 could provide shelter for casualties before decontamination. Conclusion We have identified major inconsistencies in the preparedness of North West Emergency Departments for managing chemical incidents. Nationally recognized standards on incident planning, facilities, equipment and procedures need to be agreed and implemented with adequate resources. Issues of environmental safety and patient dignity and comfort should also be addressed.

  7. Structural analysis at aircraft conceptual design stage

    Science.gov (United States)

    Mansouri, Reza

    In the past 50 years, computers have helped by augmenting human efforts with tremendous pace. The aircraft industry is not an exception. Aircraft industry is more than ever dependent on computing because of a high level of complexity and the increasing need for excellence to survive a highly competitive marketplace. Designers choose computers to perform almost every analysis task. But while doing so, existing effective, accurate and easy to use classical analytical methods are often forgotten, which can be very useful especially in the early phases of the aircraft design where concept generation and evaluation demands physical visibility of design parameters to make decisions [39, 2004]. Structural analysis methods have been used by human beings since the very early civilization. Centuries before computers were invented; the pyramids were designed and constructed by Egyptians around 2000 B.C, the Parthenon was built by the Greeks, around 240 B.C, Dujiangyan was built by the Chinese. Persepolis, Hagia Sophia, Taj Mahal, Eiffel tower are only few more examples of historical buildings, bridges and monuments that were constructed before we had any advancement made in computer aided engineering. Aircraft industry is no exception either. In the first half of the 20th century, engineers used classical method and designed civil transport aircraft such as Ford Tri Motor (1926), Lockheed Vega (1927), Lockheed 9 Orion (1931), Douglas DC-3 (1935), Douglas DC-4/C-54 Skymaster (1938), Boeing 307 (1938) and Boeing 314 Clipper (1939) and managed to become airborne without difficulty. Evidencing, while advanced numerical methods such as the finite element analysis is one of the most effective structural analysis methods; classical structural analysis methods can also be as useful especially during the early phase of a fixed wing aircraft design where major decisions are made and concept generation and evaluation demands physical visibility of design parameters to make decisions

  8. Probabilistic seismic demand analysis of nonlinear structures

    Science.gov (United States)

    Shome, Nilesh

    Recent earthquakes in California have initiated improvement in current design philosophy and at present the civil engineering community is working towards development of performance-based earthquake engineering of structures. The objective of this study is to develop efficient, but accurate procedures for probabilistic analysis of nonlinear seismic behavior of structures. The proposed procedures help the near-term development of seismic-building assessments which require an estimation of seismic demand at a given intensity level. We also develop procedures to estimate the probability of exceedance of any specified nonlinear response level due to future ground motions at a specific site. This is referred as Probabilistic Seismic Demand Analysis (PSDA). The latter procedure prepares the way for the next stage development of seismic assessment that consider the uncertainties in nonlinear response and capacity. The proposed procedures require structure-specific nonlinear analyses for a relatively small set of recorded accelerograms and (site-specific or USGS-map-like) seismic hazard analyses. We have addressed some of the important issues of nonlinear seismic demand analysis, which are selection of records for structural analysis, the number of records to be used, scaling of records, etc. Initially these issues are studied through nonlinear analysis of structures for a number of magnitude-distance bins of records. Subsequently we introduce regression analysis of response results against spectral acceleration, magnitude, duration, etc., which helps to resolve these issues more systematically. We illustrate the demand-hazard calculations through two major example problems: a 5story and a 20-story SMRF building. Several simple, but quite accurate closed-form solutions have also been proposed to expedite the demand-hazard calculations. We find that vector-valued (e.g., 2-D) PSDA estimates demand hazard more accurately. This procedure, however, requires information about 2

  9. Analysis of nonlinear structures via mode synthesis

    Science.gov (United States)

    Gieseke, R. K.

    1975-01-01

    An effective procedure for NASTRAN was developed that permits any number of substructures of any size to be synthesized for the purpose of developing normal modes of vibration of the complete structural system. The technique is extended to permit modal transient analysis of the subdivided system. This latter procedure permits the use of NASTRAN's ability to include nonlinear forces in the problem. The five-phase process is accomplished using standard NASTRAN rigid formats with problem-independent alter packages and DMAP sequences.

  10. Sequence and structural analysis of antibodies

    OpenAIRE

    Raghavan, A. K.

    2009-01-01

    The work presented in this thesis focusses on the sequence and structural analysis of antibodies and has fallen into three main areas. First I developed a method to assess how typical an antibody sequence is of the expressed human antibody repertoire. My hypothesis was that the more \\humanlike" an antibody sequence is (in other words how typical it is of the expressed human repertoire), the less likely it is to elicit an immune response when used in vivo in humans. In practi...

  11. Growth control, structure, chemical state, and photoresponse of CuO-CdS core-shell heterostructure nanowires.

    Science.gov (United States)

    El Mel, A A; Buffière, M; Bouts, N; Gautron, E; Tessier, P Y; Henzler, K; Guttmann, P; Konstantinidis, S; Bittencourt, C; Snyders, R

    2013-07-01

    The growth of single-crystal CuO nanowires by thermal annealing of copper thin films in air is studied. We show that the density, length, and diameter of the nanowires can be controlled by tuning the morphology and structure of the copper thin films deposited by DC magnetron sputtering. After identifying the optimal conditions for the growth of CuO nanowires, chemical bath deposition is employed to coat the CuO nanowires with CdS in order to form p-n nanojunction arrays. As revealed by high-resolution TEM analysis, the thickness of the polycrystalline CdS shell increases when decreasing the diameter of the CuO core for a given time of CdS deposition. Near-edge x-ray absorption fine-structure spectroscopy combined with transmission x-ray microscopy allows the chemical analysis of isolated nanowires. The absence of modification in the spectra at the Cu L and O K edges after the deposition of CdS on the CuO nanowires indicates that neither Cd nor S diffuse into the CuO phase. We further demonstrate that the core-shell nanowires exhibit the I-V characteristic of a resistor instead of a diode. The electrical behavior of the device was found to be photosensitive, since increasing the incident light intensity induces an increase in the collected electrical current. PMID:23732175

  12. Growth control, structure, chemical state, and photoresponse of CuO-CdS core-shell heterostructure nanowires.

    Science.gov (United States)

    El Mel, A A; Buffière, M; Bouts, N; Gautron, E; Tessier, P Y; Henzler, K; Guttmann, P; Konstantinidis, S; Bittencourt, C; Snyders, R

    2013-07-01

    The growth of single-crystal CuO nanowires by thermal annealing of copper thin films in air is studied. We show that the density, length, and diameter of the nanowires can be controlled by tuning the morphology and structure of the copper thin films deposited by DC magnetron sputtering. After identifying the optimal conditions for the growth of CuO nanowires, chemical bath deposition is employed to coat the CuO nanowires with CdS in order to form p-n nanojunction arrays. As revealed by high-resolution TEM analysis, the thickness of the polycrystalline CdS shell increases when decreasing the diameter of the CuO core for a given time of CdS deposition. Near-edge x-ray absorption fine-structure spectroscopy combined with transmission x-ray microscopy allows the chemical analysis of isolated nanowires. The absence of modification in the spectra at the Cu L and O K edges after the deposition of CdS on the CuO nanowires indicates that neither Cd nor S diffuse into the CuO phase. We further demonstrate that the core-shell nanowires exhibit the I-V characteristic of a resistor instead of a diode. The electrical behavior of the device was found to be photosensitive, since increasing the incident light intensity induces an increase in the collected electrical current.

  13. Linking advanced fracture models to structural analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chiesa, Matteo

    2001-07-01

    Shell structures with defects occur in many situations. The defects are usually introduced during the welding process necessary for joining different parts of the structure. Higher utilization of structural materials leads to a need for accurate numerical tools for reliable prediction of structural response. The direct discretization of the cracked shell structure with solid finite elements in order to perform an integrity assessment of the structure in question leads to large size problems, and makes such analysis infeasible in structural application. In this study a link between local material models and structural analysis is outlined. An ''ad hoc'' element formulation is used in order to connect complex material models to the finite element framework used for structural analysis. An improved elasto-plastic line spring finite element formulation, used in order to take cracks into account, is linked to shell elements which are further linked to beam elements. In this way one obtain a global model of the shell structure that also accounts for local flexibilities and fractures due to defects. An important advantage with such an approach is a direct fracture mechanics assessment e.g. via computed J-integral or CTOD. A recent development in this approach is the notion of two-parameter fracture assessment. This means that the crack tip stress tri-axiality (constraint) is employed in determining the corresponding fracture toughness, giving a much more realistic capacity of cracked structures. The present thesis is organized in six research articles and an introductory chapter that reviews important background literature related to this work. Paper I and II address the performance of shell and line spring finite elements as a cost effective tool for performing the numerical calculation needed to perform a fracture assessment. In Paper II a failure assessment, based on the testing of a constraint-corrected fracture mechanics specimen under tension, is

  14. A comparative study of blue, green and yellow light emitting diode structures grown by metal organic chemical vapor deposition

    Science.gov (United States)

    Ramaiah, Kodigala Subba; Su, Y. K.; Chang, S. J.; Chen, C. H.

    2006-02-01

    The blue, green and yellow light emitting diode (LED) structures have been fabricated by metal organic chemical vapor deposition (MOCVD), and characterized by using different techniques, in order to understand the mechanism between these LEDs. Atomic force microscopy (AFM) analysis revealed that the surface roughness value and density of etch pits were different in the blue, green and yellow LEDs. The threading, misfit dislocations, interfacial dislocations, nano-pipe-like structures and quantum dot-like structures, which determine quality of the structures, were observed by transmission electron microscope (TEM) in the LED structures. The reasons for their formation in the layers are now elucidated. The indium composition, period width such as well and barrier widths were determined by simulating experimental high resolution X-ray diffraction (HRXRD) spectra. The In composition obtained by HRXRD and photoluminescence (PL) measurements for the same LED structure was not one and the same due to several reasons. In fact, the InGaN quantum well emission peaks at 2.667 and 2.544 eV of the blue and green LEDs, respectively showed S-shaped character shift, whereas the quantum well peak at 2.219 eV of yellow LEDs did not show any shift in the PL spectra with decreasing temperature. The blue, green and yellow LEDs showed different activation energies.

  15. Survey of marine natural product structure revisions: a synergy of spectroscopy and chemical synthesis.

    Science.gov (United States)

    Suyama, Takashi L; Gerwick, William H; McPhail, Kerry L

    2011-11-15

    The structural assignment of new natural product molecules supports research in a multitude of disciplines that may lead to new therapeutic agents and or new understanding of disease biology. However, reports of numerous structural revisions, even of recently elucidated natural products, inspired the present survey of techniques used in structural misassignments and subsequent revisions in the context of constitutional or configurational errors. Given the comparatively recent development of marine natural products chemistry, coincident with modern spectroscopy, it is of interest to consider the relative roles of spectroscopy and chemical synthesis in the structure elucidation and revision of those marine natural products that were initially misassigned. Thus, a tabulated review of all marine natural product structural revisions from 2005 to 2010 is organized according to structural motif revised. Misassignments of constitution are more frequent than perhaps anticipated by reliance on HMBC and other advanced NMR experiments, especially when considering the full complement of all natural products. However, these techniques also feature prominently in structural revisions, specifically of marine natural products. Nevertheless, as is the case for revision of relative and absolute configuration, total synthesis is a proven partner for marine, as well as terrestrial, natural products structure elucidation. It also becomes apparent that considerable 'detective work' remains in structure elucidation, in spite of the spectacular advances in spectroscopic techniques.

  16. Neurodevelopmental toxicity of prenatal polychlorinated biphenyls (PCBs) by chemical structure and activity: a birth cohort study

    OpenAIRE

    Park Hye-Youn; Hertz-Picciotto Irva; Sovcikova Eva; Kocan Anton; Drobna Beata; Trnovec Tomas

    2010-01-01

    Abstract Background Polychlorinated biphenyls (PCBs) are ubiquitous environmental toxins. Although there is growing evidence to support an association between PCBs and deficits of neurodevelopment, the specific mechanisms are not well understood. The potentially different roles of specific PCB groups defined by chemical structures or hormonal activities e.g., dioxin-like, non-dioxin like, or anti-estrogenic PCBs, remain unclear. Our objective was to examine the association between prenatal ex...

  17. Studies on chemical constituents of the leaves of Smallantus sonchifolius (yacon): structures of two new diterpenes.

    Science.gov (United States)

    Dou, De-Qiang; Tian, Fang; Qiu, Ying-Kun; Xiang, Zheng; Xu, Bi Xia; Kang, Ting Guo; Dong, Feng

    2010-01-01

    The extract from the leaves of Smallantus sonchifolius (yacon) was found to show potent anti-diabetic activity. Two new diterpenes, named ent-kaurane-3beta,16beta,17, 19-tetrol (1) and ent-kaurane-16beta,17,18,19-tetrol (2), were isolated from the extract, together with six known compounds. The structures of the new compounds were determined on the basis of chemical and physicochemical evidence. PMID:20013471

  18. Preparation and Characterization of Chitosan/Agar Blended Films: Part 1. Chemical Structure and Morphology

    OpenAIRE

    Esam A. El-Hefian; Mohamed Mahmoud NASEF; Yahaya, Abdul Hamid

    2012-01-01

    Chitosan/agar (CS/AG) films were prepared by blending different proportions of chitosan and agar (considering chitosan as the main component) in solution forms. The chemical structure and the morphology of the obtained blended films were investigated using Fourier transform infrared (FTIR) and field emission scanning electron microscope (FESEM). It was revealed that chitosan and agar form a highly compatible blend and their films displayed homogenous and smooth surface properties compared to ...

  19. Ultra-spatial synchrotron radiation for imaging molecular chemical structure: Applications in plant and animal studies

    OpenAIRE

    Yu, Peiqiang

    2007-01-01

    Synchrotron-based Fourier transform infrared microspectroscopy (S-FTIR) has been developed as a rapid, direct, non-destructive, bioanalytical technique. This technique takes advantage of synchrotron light brightness and small effective source size and is capable of exploring the molecular chemical features and make-up within microstructures of a biological tissue without destruction of inherent structures at ultra-spatial resolutions within cellular dimension. To date there has been very litt...

  20. Relationship between the antitrichinellous effect of seven derivates of benzimidazolecarbamates and their chemical structure.

    Science.gov (United States)

    Spaldonová, R; Corba, J

    1979-01-01

    The efficacy of seven more recently developed anthelmintics of the benzimidazolecarbamate group, i. e., parbendazole, mebendazole, fenbendazole, oxibendazole, cambendazole, oxfendazole and albendazole, has been tested in a series of experiments on white mice artifically infected with Trichinella spiralis. Our results disclosed a relationship between their anthelmintic effect and their chemical structure. This finding might be of importance in a targeted synthesis of new, effective, derivates of benzimidazole, e. g., in the therapy of trichinellosis and in the choice of the most effective drug.

  1. Physico-chemical properties and cytotoxic effects of sugar-based surfactants: Impact of structural variations.

    Science.gov (United States)

    Lu, Biao; Vayssade, Muriel; Miao, Yong; Chagnault, Vincent; Grand, Eric; Wadouachi, Anne; Postel, Denis; Drelich, Audrey; Egles, Christophe; Pezron, Isabelle

    2016-09-01

    Surfactants derived from the biorefinery process can present interesting surface-active properties, low cytotoxicity, high biocompatibility and biodegradability. They are therefore considered as potential sustainable substitutes to currently used petroleum-based surfactants. To better understand and anticipate their performances, structure-property relationships need to be carefully investigated. For this reason, we applied a multidisciplinary approach to systematically explore the effect of subtle structural variations on both physico-chemical properties and biological effects. Four sugar-based surfactants, each with an eight carbon alkyl chain bound to a glucose or maltose head group by an amide linkage, were synthesized and evaluated together along with two commercially available standard surfactants. Physico-chemical properties including solubility, Krafft point, surface-tension lowering and critical micellar concentration (CMC) in water and biological medium were explored. Cytotoxicity evaluation by measuring proliferation index and metabolic activity against dermal fibroblasts showed that all surfactants studied may induce cell death at low concentrations (below their CMC). Results revealed significant differences in both physico-chemical properties and cytotoxic effects depending on molecule structural features, such as the position of the linkage on the sugar head-group, or the orientation of the amide linkage. Furthermore, the cytotoxic response increased with the reduction of surfactant CMC. This study underscores the relevance of a methodical and multidisciplinary approach that enables the consideration of surfactant solution properties when applied to biological materials. Overall, our results will contribute to a better understanding of the concomitant impact of surfactant structure at physico-chemical and biological levels. PMID:27137806

  2. Structural Integrity Analysis of CEA Change Platform

    International Nuclear Information System (INIS)

    The Control Element Assembly Change Platform (CEA CP) is similar to a gantry crane. The CEA CP for Shin-Kori units 3 and 4 (SKN 3 and 4) consists of a bridge, which spans the reactor cavity pool and a gantry superstructure mounted on the bridge. The structure is approximately 8.8 m wide, 4.9 m long and 10.6 m high. The gantry superstructure supports one ton capacity hoist trolley and the bridge supports the In Core Instrumentation (ICI) retrieval cart which moves along the bridge. This paper presents the dynamic and structural analysis of CEA CP which is greater than that of the previous nuclear power plants to verify the structural integrity under the application of the earthquake spectrum. The analysis have been performed using the three orthogonal SSE response spectrum for SKN 3 and 4 which shows much higher acceleration value than OPR- 1000 Plants. In addition, the analyses are performed by 3-dimensional finite element analysis using ANSYS software

  3. Structure soil structure interaction effects: Seismic analysis of safety related collocated concrete structures

    International Nuclear Information System (INIS)

    The Process, Purification and Stack Buildings are collocated safety related concrete shear wall structures with plan dimensions in excess of 100 feet. An important aspect of their seismic analysis was the determination of structure soil structure interaction (SSSI) effects, if any. The SSSI analysis of the Process Building, with one other building at a time, was performed with the SASSI computer code for up to 50 frequencies. Each combined model had about 1500 interaction nodes. Results of the SSSI analysis were compared with those from soil structure interaction (SSI) analysis of the individual buildings, done with ABAQUS and SASSI codes, for three parameters: peak accelerations, seismic forces and the in-structure floor response spectra (FRS). The results may be of wider interest due to the model size and the potential applicability to other deep soil layered sites. Results obtained from the ABAQUS analysis were consistently higher, as expected, than those from the SSI and SSSI analyses using the SASSI. The SSSI effect between the Process and Purification Buildings was not significant. The Process and Stack Building results demonstrated that under certain conditions a massive structure can have an observable effect on the seismic response of a smaller and less stiff structure

  4. Structure soil structure interaction effects: Seismic analysis of safety related collocated concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, J.R.

    2000-06-20

    The Process, Purification and Stack Buildings are collocated safety related concrete shear wall structures with plan dimensions in excess of 100 feet. An important aspect of their seismic analysis was the determination of structure soil structure interaction (SSSI) effects, if any. The SSSI analysis of the Process Building, with one other building at a time, was performed with the SASSI computer code for up to 50 frequencies. Each combined model had about 1500 interaction nodes. Results of the SSSI analysis were compared with those from soil structure interaction (SSI) analysis of the individual buildings, done with ABAQUS and SASSI codes, for three parameters: peak accelerations, seismic forces and the in-structure floor response spectra (FRS). The results may be of wider interest due to the model size and the potential applicability to other deep soil layered sites. Results obtained from the ABAQUS analysis were consistently higher, as expected, than those from the SSI and SSSI analyses using the SASSI. The SSSI effect between the Process and Purification Buildings was not significant. The Process and Stack Building results demonstrated that under certain conditions a massive structure can have an observable effect on the seismic response of a smaller and less stiff structure.

  5. Damascene Array Structure of Phase Change Memory Fabricated with Chemical Mechanical Polishing Method

    Institute of Scientific and Technical Information of China (English)

    LIU Qi-Bin; SONG Zhi-Tang; ZHANG Kai-Liang; WANG Liang-Yong; FENG Song-Lin; CHEN Bomy

    2006-01-01

    @@ A damascene structure of phase change memory (PCM) is fabricated successfully with the chemical mechanical polishing (CMP) method, and the CMP of Ge2Sb2Te5 (GST) and Ti films is investigated. The polished surface of wafer is analysed by scanning electron microscopy (SEM) and an energy dispersive spectrometer (EDS). The measurements show that the damascene device structure of phase change memory is achieved by the CMP process.After the top electrode is deposited, dc sweeping test on PCM reveals that the phase change can be observed.The threshold current of array cells varies between 0.90mA and 1.15mA.

  6. Electronic structure and chemical bonding of Li4Pt3Si

    Science.gov (United States)

    Matar, S. F.; Pöttgen, R.; Al Alam, A. F.; Ouaini, N.

    2012-07-01

    The electronic structure of rhombohedral Li4Pt3Si (space group R32) is examined from ab initio with an assessment of the properties of chemical bonding relating to the presence of different Li and Pt Wyckoff sites. The structure with totally de-intercalated Li keeps the characteristics of the pristine compound with a reduction of the volume albeit with less cohesive energy. The binding energies of Li point to different bonding intensities according to their different Wyckoff sites and indicate the possibility of delithiation.

  7. Probing Structural and Catalytic Characteristics of Galactose Oxidase Confined in Nanoscale Chemical Environments

    DEFF Research Database (Denmark)

    Ikemoto, Hideki; Mossin, Susanne; Ulstrup, Jens;

    2014-01-01

    Galactose oxidase (GAOX) is a special metalloenzyme in terms of its active site structure and catalytic mechanisms. This work reports a study where the enzyme confined in a nanoscale chemical environment provided by mesoporous silicas (MPS) is probed. Two types of MPS, i.e. SBA-15 and MCF, were...... synthesized and used to accommodate GAOX. SBA-15-ROD is rod-shaped particles with periodically ordered nanopores (9.5 nm), while MCF has a mesocellular foam-like structure with randomly distributed pores (23 nm) interconnected by smaller windows (8.8 nm). GAOX is non-covalently confined in SBA-15- ROD, while...

  8. Study and structural and chemical characterization of human dental smalt by electron microscopy

    International Nuclear Information System (INIS)

    The study of human dental smalt has been subject to investigation for this methods with electron microscopy, electron diffraction, X-ray diffraction and image simulation programs have been used with the purpose to determine its chemical and structural characteristics of the organic and inorganic materials. This work has been held mainly for the characterization of hydroxyapatite (Ca)10 (PO4)6 (OH4)2, inorganic material which conforms the dental smalt in 97%, so observing its structural unity which is composed by the prisms and these by crystals and atoms. It was subsequently initiated the study of the organic material, with is precursor of itself. (Author)

  9. Mass spectrometry analysis of polychlorinated biphenyls: chemical ionization and selected ion chemical ionization using methane as a reagent gas

    OpenAIRE

    RAYMOND E. MARCH; MILA D. LAUSEVIC; TATJANA M. VASILJEVIC

    2000-01-01

    In the present paper a quadrupole ion trap mass spectrometer, coupled with a gas chromatograph, was used to compare the electron impact ionization (EI) and chemical ionization (Cl) technique, in terms of their selectivity in polychlorinated biphenyls (PCBs) quantitative analysis. The experiments were carried out with a modified Varian SATURN III quadrupole ion-storage mass spectrometer equipped with Varian waveform generator, coupled with a gas chromatograph with DB-5 capillary column. The di...

  10. Probabilistic thermo-chemical analysis of a pultruded composite rod

    NARCIS (Netherlands)

    Baran, Ismet; Tutum, Cem C.; Hattel, Jesper H.

    2012-01-01

    In the present study the deterministic thermo-chemical pultrusion simulation of a composite rod taken from the literature [7] is used as a validation case. The predicted centerline temperature and cure degree profiles of the rod match well with those in the literature [7]. Following the validation c

  11. Analysis of chemical coal cleaning processes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    Six chemical coal cleaning processes were examined. Conceptual designs and costs were prepared for these processes and coal preparation facilities, including physical cleaning and size reduction. Transportation of fine coal in agglomerated and unagglomerated forms was also discussed. Chemical cleaning processes were: Pittsburgh Energy Technology Center, Ledgemont, Ames Laboratory, Jet Propulsion Laboratory (two versions), and Guth Process (KVB). Three of the chemical cleaning processes are similar in concept: PETC, Ledgemont, and Ames. Each of these is based on the reaction of sulfur with pressurized oxygen, with the controlling factor being the partial pressure of oxygen in the reactor. All of the processes appear technically feasible. Economic feasibility is less certain. The recovery of process chemicals is vital to the JPL and Guth processes. All of the processes consume significant amounts of energy in the form of electric power and coal. Energy recovery and increased efficiency are potential areas for study in future more detailed designs. The Guth process (formally designed KVB) appears to be the simplest of the systems evaluated. All of the processes require future engineering to better determine methods for scaling laboratory designs/results to commercial-scale operations. A major area for future engineering is to resolve problems related to handling, feeding, and flow control of the fine and often hot coal.

  12. Portfolio Assessment on Chemical Reactor Analysis and Process Design Courses

    Science.gov (United States)

    Alha, Katariina

    2004-01-01

    Assessment determines what students regard as important: if a teacher wants to change students' learning, he/she should change the methods of assessment. This article describes the use of portfolio assessment on five courses dealing with chemical reactor and process design during the years 1999-2001. Although the use of portfolio was a new…

  13. Beyond terrestrial biology: charting the chemical universe of α-amino acid structures.

    Science.gov (United States)

    Meringer, Markus; Cleaves, H James; Freeland, Stephen J

    2013-11-25

    α-Amino acids are fundamental to biochemistry as the monomeric building blocks with which cells construct proteins according to genetic instructions. However, the 20 amino acids of the standard genetic code represent a tiny fraction of the number of α-amino acid chemical structures that could plausibly play such a role, both from the perspective of natural processes by which life emerged and evolved, and from the perspective of human-engineered genetically coded proteins. Until now, efforts to describe the structures comprising this broader set, or even estimate their number, have been hampered by the complex combinatorial properties of organic molecules. Here, we use computer software based on graph theory and constructive combinatorics in order to conduct an efficient and exhaustive search of the chemical structures implied by two careful and precise definitions of the α-amino acids relevant to coded biological proteins. Our results include two virtual libraries of α-amino acid structures corresponding to these different approaches, comprising 121 044 and 3 846 structures, respectively, and suggest a simple approach to exploring much larger, as yet uncomputed, libraries of interest.

  14. Magnetism, structure and chemical order in small FeRh clusters

    Energy Technology Data Exchange (ETDEWEB)

    Mokkath, Junais; Pastor, Gustavo [Institut fuer Theoretische Physik, Universitaet Kassel (Germany)

    2010-07-01

    The structural, electronic and magnetic properties of small Fe{sub m}Rh{sub n} clusters having N=m+n{<=}8 atoms are investigated in the framework of a generalized gradient approximation to density-functional theory. The optimized cluster structures are compact with a clear tendency to maximize the number of nearest-neighbor FeRh pairs. For very small sizes the low-lying isomers present a different topology than the optimal structure, while for larger clusters the lowest-energy isomerizations imply mainly changes in the chemical order. The correlation between structure, chemical order, and magnetic behavior is analyzed as a function of size and composition. For all clusters having the optimized most stable structure the magnetic order is found to be Ferromagnetic-like, Antiferromagnetic-like spin arrangements were found in some low-lying isomers. The average magnetic moment per atom anti {mu}{sub N} increases approximately linearly with Fe content. A remarkable enhancement of the local Fe moments is observed as result of Rh doping. This is a consequence of the increase in the number of Fe d holes, due to FeRh charge transfer, combined with the extremely reduced local coordination. The Rh local moments, which are important already in the pure clusters (N{<=}8) are not significantly enhanced by Fe doping. However, the overall stability of magnetism- as measured by the total energy gain upon spin polarization at T=0 increases when Rh is replaced by Fe.

  15. Study on the electronic structure of nickel hydroxide by quantum chemical DV-Xα calculation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The electronic structures of atom clusters Ni7O12H122+and Ni7O12H-9 of β-Ni(OH)2 were calculated by quantum chemical DV-Xα method.By analyzing the state densities,orbital populations,net charges and electric charge density differences of the selected clusters,it was indicated that β-Ni(OH)2 was not typical ionic crystal,and the bonds between Ni and O atoms had obvious covalent characteristics.The bonds between H atom and other atoms in the crystal structure were weaker,which ensured that H atoms can easily deintercalate and intercalate into β-Ni(OH)2-The structure of β-Ni(OH)2 was not changed by moderate de-intercalation of H atoms.However,with the excessive de-intercalation of H atoms,the structure of β-Ni(OH)2 changed and the electrochemical active properties were reduced.

  16. Optical and Structural Properties of Nanocrystalline CdS Thin Films Grown by Chemical Bath Deposition

    International Nuclear Information System (INIS)

    Nanocrystalline cadmium sulfide thin films are prepared using chemical bath deposition (CBD) technique in aqueous alkaline bath at 60 degree Celsius and their subsequent condensation on glass substrates. Effects of annealing on structural, morphological and optical properties are presented and discussed. The best annealing temperature for CBD grown CdS films is found to be 350 degree Celsius from optical properties. The optical and structural properties of CdS films are found to be sensitive to annealing temperature and are described in terms of XRD, SEM, transmission spectra and optical studies. The structural parameters such as crystallite size have been evaluated through XRD while SEM micrographs exhibit ordering of grains after annealing. The transmission spectra shift towards higher wavelength upon annealing indicating increase in crystallinity. Annealing over 350 degree Celsius is found to degrade the external structure and optical properties of the film. (author)

  17. Changes in the chemical structure of polytetrafluoroethylene induced by electron beam irradiation in the molten state

    CERN Document Server

    Lappan, U; Lunkwitz, K

    2000-01-01

    Polytetrafluoroethylene (PTFE) was exposed to electron beam radiation at elevated temperature above the melting point under nitrogen atmosphere and in vacuum for comparison. Fourier-transform infrared (FTIR) spectroscopy was used to study the changes in the chemical structure. The irradiation under nitrogen atmosphere leads to the same structures as described recently for PTFE irradiated in vacuum. Trifluoromethyl branches and double bond structures were detected. The concentrations of terminal and internal double bonds are higher after irradiation under nitrogen than in vacuum. Annealing experiments have shown that the thermal oxidative stability of the radiation-modified PTFE is reduced compared to unirradiated PTFE. The reason are the formation of unstable structures such as double bonds.

  18. Elucidating the Link between NMR Chemical Shifts and Electronic Structure in d(0) Olefin Metathesis Catalysts.

    Science.gov (United States)

    Halbert, Stéphanie; Copéret, Christophe; Raynaud, Christophe; Eisenstein, Odile

    2016-02-24

    The nucleophilic carbon of d(0) Schrock alkylidene metathesis catalysts, [M] = CHR, display surprisingly low downfield chemical shift (δ(iso)) and large chemical shift anisotropy. State-of-the-art four-component relativistic calculations of the chemical shift tensors combined with a two-component analysis in terms of localized orbitals allow a molecular-level understanding of their orientations, the magnitude of their principal components (δ11 > δ22 > δ33) and associated δ(iso). This analysis reveals the dominating influence of the paramagnetic contribution yielding a highly deshielded alkylidene carbon. The largest paramagnetic contribution, which originates from the coupling of alkylidene σ(MC) and π*(MC) orbitals under the action of the magnetic field, is analogous to that resulting from coupling σ(CC) and π*(CC) in ethylene; thus, δ11 is in the MCH plane and is perpendicular to the MC internuclear direction. The higher value of carbon-13 δ(iso) in alkylidene complexes relative to ethylene is thus due to the smaller energy gap between σ(MC) and π*(MC) vs this between σ(CC) and π*(CC) in ethylene. This effect also explains why the highest value of δ(iso) is observed for Mo and the lowest for Ta, the values for W and Re being in between. In the presence of agostic interaction, the chemical shift tensor principal components orientation (δ22 or δ33 parallel or perpendicular to π(MX)) is influenced by the MCH angle because it determines the orientation of the alkylidene CHR fragment relative to the MC internuclear axis. The orbital analysis shows how the paramagnetic terms, understood with a localized bond model, determine the chemical shift tensor and thereby δ(iso). PMID:26787258

  19. Elucidating the Link between NMR Chemical Shifts and Electronic Structure in d(0) Olefin Metathesis Catalysts.

    Science.gov (United States)

    Halbert, Stéphanie; Copéret, Christophe; Raynaud, Christophe; Eisenstein, Odile

    2016-02-24

    The nucleophilic carbon of d(0) Schrock alkylidene metathesis catalysts, [M] = CHR, display surprisingly low downfield chemical shift (δ(iso)) and large chemical shift anisotropy. State-of-the-art four-component relativistic calculations of the chemical shift tensors combined with a two-component analysis in terms of localized orbitals allow a molecular-level understanding of their orientations, the magnitude of their principal components (δ11 > δ22 > δ33) and associated δ(iso). This analysis reveals the dominating influence of the paramagnetic contribution yielding a highly deshielded alkylidene carbon. The largest paramagnetic contribution, which originates from the coupling of alkylidene σ(MC) and π*(MC) orbitals under the action of the magnetic field, is analogous to that resulting from coupling σ(CC) and π*(CC) in ethylene; thus, δ11 is in the MCH plane and is perpendicular to the MC internuclear direction. The higher value of carbon-13 δ(iso) in alkylidene complexes relative to ethylene is thus due to the smaller energy gap between σ(MC) and π*(MC) vs this between σ(CC) and π*(CC) in ethylene. This effect also explains why the highest value of δ(iso) is observed for Mo and the lowest for Ta, the values for W and Re being in between. In the presence of agostic interaction, the chemical shift tensor principal components orientation (δ22 or δ33 parallel or perpendicular to π(MX)) is influenced by the MCH angle because it determines the orientation of the alkylidene CHR fragment relative to the MC internuclear axis. The orbital analysis shows how the paramagnetic terms, understood with a localized bond model, determine the chemical shift tensor and thereby δ(iso).

  20. Analysis of waveguiding properties of VCSEL structures

    Energy Technology Data Exchange (ETDEWEB)

    Erteza, I.A. [Sandia National Labs., Albuquerque, NM (United States). Exploratory Systems Development Center

    1996-09-01

    In this paper, the authors explore the feasibility of using the distributed Bragg reflector, grown on the substrate for a VCSEL (Vertical Cavity Surface Emitting Laser), to provide waveguiding within the substrate. This waveguiding could serve as an interconnection among VCSELs in an array. Before determining the feasibility of waveguide interconnected VCSELs, two analysis methods are presented and evaluated for their applicability to this problem. The implementations in Mathematica of both these methods are included. Results of the analysis show that waveguiding in VCSEL structures is feasible. Some of the many possible uses of waveguide interconnected VCSELs are also briefly discussed. The tools and analysis presented in this report can be used to evaluate such system concepts and to do detailed design calculations.