WorldWideScience

Sample records for chemical signature study

  1. Do open clusters have distinguishable chemical signatures?

    CERN Document Server

    Blanco-Cuaresma, S; Heiter, U

    2015-01-01

    Past studies have already shown that stars in open clusters are chemically homogeneous (e.g. De Silva et al. 2006, 2007 and 2009). These results support the idea that stars born from the same giant molecular cloud should have the same chemical composition. In this context, the chemical tagging technique was proposed by Freeman et al. 2002. The principle is to recover disrupted stellar clusters by looking only to the stellar chemical composition. In order to evaluate the feasibility of this approach, it is necessary to test if we can distinguish between stars born from different molecular clouds. For this purpose, we studied the chemical composition of stars in 32 old and intermediate-age open clusters, and we applied machine learning algorithms to recover the original cluster by only considering the chemical signatures.

  2. Chemical signature study of tupiguarani ceramic tradition from Central region of the Rio Grande do Sul state, Brazil

    International Nuclear Information System (INIS)

    In this work a model based on experimental results using chemical composition data of the pottery sherds applied to Spearmann's no parametric test, principal component analysis and discriminant analysis, was applied. The samples are soils and Tupiguarani Tradition pottery sherd from the central area of the Rio Grande do Sul State. The chemical elements , Al, Ba, Ca, Cr, Fe, K Mn, Pb, Rb, S, Si, Sr, Ti, V and Zn were determined by energy dispersive X-ray fluorescence (EDXFR) while Ce, Cu, Gd, La, Nd, Pr, Sm, Th and Y by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) techniques. Relationships among the pottery characteristics, studied sites and sherd dispersion in the several sites were proposed. Indications of chemical signature of the small pottery with function to go or not to the fire were observed. The largest dispersion is of small pottery with surface treatment no corrugated. The potteries chemical fingerprints from Ijui River, Ibicui-Vacacai Mirim River and Jacui River were verified. (author)

  3. Alterations in the infrared spectral signature of avian feathers reflect potential chemical exposure: a pilot study comparing two sites in Pakistan.

    Science.gov (United States)

    Llabjani, Valon; Malik, Riffat N; Trevisan, Júlio; Hoti, Valmira; Ukpebor, Justina; Shinwari, Zabta K; Moeckel, Claudia; Jones, Kevin C; Shore, Richard F; Martin, Francis L

    2012-11-01

    Chemical contamination of ecosystems is a global issue with evidence that pollutants impact on living organisms in a harmful fashion. Developing sensor approaches that would allow the derivation of biomarkers or signatures of effect in target sentinel organisms and monitor environmental chemical contamination in a high throughput manner is of utmost importance. As biomolecules absorb infrared (IR), signature vibrational spectra related to structure and function can be derived. In light of this, we tested the notion that IR spectra of bird feathers might reflect environmental chemical contaminant exposure patterns. Feathers were collected from monospecific heronries of cattle egret based in two independent locations (Trimu vs. Mailsi) in the Punjab province of Pakistan; these sites were found to differ in their chemical contamination patterns. Feather samples were chemically analyzed for polychlorinated biphenyls, polybrominated diphenyl ethers, organochlorines and heavy metals. Attenuated total reflection Fourier-transform IR (ATR-FTIR) spectroscopy was employed to derive a spectral signature of individual feathers. Resultant IR spectra were then subjected to canonical correspondence analysis (CAA) to determine whether feather spectral signatures correlate to chemical exposure. Additionally, we explored if principal component analysis (PCA) and linear discriminant analysis (LDA) could be applied to distinguish site-specific differences; linear discriminant function (LDF) was also applied to classify sites. The sampled feathers varied in their chemical exposure patterns depending on whether they were sourced from one site associated with heavy metal exposure or the other which suggested high organic pollutant exposures. CCA of chemical and spectral data showed a correlation between spectral signatures and chemical exposure. PCA-LDA readily distinguished feathers from the two different sites. Discriminating alterations were identified and these were associated with

  4. Chemical signatures of planets: beyond solar-twins

    OpenAIRE

    Ramirez, I.; Melendez, J.; Asplund, M.

    2013-01-01

    Elemental abundance studies of solar twin stars suggest that the solar chemical composition contains signatures of the formation of terrestrial planets in the solar system, namely small but significant depletions of the refractory elements. To test this hypothesis, we study stars which, compared to solar twins, have less massive convective envelopes (therefore increasing the amplitude of the predicted effect) or are, arguably, more likely to host planets (thus increasing the frequency of sign...

  5. Study of the chemical evolution and spectral signatures of some interstellar precursor molecules of adenine, glycine alanine

    CERN Document Server

    Majumdar, Liton; Chakrabarti, Sandip K; Chakrabarti, Sonali; 10.1016/j.newast.2012.09.002

    2012-01-01

    We carry out a quantum chemical calculation to obtain the infrared and electronic absorption spectra of several complex molecules of the interstellar medium (ISM). These molecules are the precursors of adenine, glycine & alanine. They could be produced in the gas phase as well as in the ice phase. We carried out a hydro-chemical simulation to predict the abundances of these species in the gas as well as in the ice phase. Gas and grains are assumed to be interacting through the accretion of various species from the gas phase on to the grain surface and desorption (thermal evaporation and photo-evaporation) from the grain surface to the gas phase. Depending on the physical properties of the cloud, the calculated abundances varies. The influence of ice on vibrational frequencies of different pre-biotic molecules was obtained using Polarizable Continuum Model (PCM) model with the integral equation formalism variant (IEFPCM) as default SCRF method with a dielectric constant of 78.5. Time dependent density func...

  6. Signatures of Chemical Evolution in Protostellar Nebulae

    Science.gov (United States)

    Nuth, Joseph A., III; Johnson, Natasha

    2011-01-01

    A decade ago observers began to take serious notice of the presence of crystalline silicate grains in the dust flowing away from some comets. While crystallinity had been seen in such objects previously, starting with the recognitions by Campins and Ryan (1990) that the 10 micron feature of Comet Halley resembled that of the mineral forsterite, most such observations were either ignored or dismissed as no path to explain such crystalline grains was available in the literature. When it was first suggested that an outward flow must be present to carry annealed silicate grains from the innermost regions of the Solar Nebula out to the regions where comets could form (Nuth, 1999; 2001) this suggestion was also dismissed because no such transport mechanism was known at the time. Since then not only have new models of nebular dynamics demonstrated the reality of long distance outward transport (Ciesla, 2007; 2008; 2009) but examination of older models (Boss, 2004) showed that such transport had been present but had gone unrecognized for many years. The most unassailable evidence for outward nebular transport came with the return of the Stardust samples from Comet Wild2, a Kuiper-belt comet that contained micron-scale grains of high temperature minerals resembling the Calcium-Aluminum Inclusions found in primitive meteorites (Zolensky et aI., 2006) that formed at T > 1400K. Now that outward transport in protostellar nebulae has been firmly established, a re-examination of its consequences for nebular gas is in order that takes into account both the factors that regulate both the outward flow as well as those that likely control the chemical composition of the gas. Laboratory studies of surface catalyzed reactions suggest that a trend toward more highly reduced carbon and nitrogen compounds in the gas phase should be correlated with a general increase in the crystallinity of the dust (Nuth et aI., 2000), but is such a trend actually observable? Unlike the Fischer-Tropsch or

  7. Infrared signature studies of aerospace vehicles

    Science.gov (United States)

    Mahulikar, Shripad P.; Sonawane, Hemant R.; Arvind Rao, G.

    2007-10-01

    Infrared (IR) emissions from aircraft are used to detect, track, and lock-on to the target. MAN Portable Air Defence Systems (MANPADS) have emerged as a major cause of aircraft and helicopter loss. Therefore, IR signature studies are important to counter this threat for survivability enhancement, and are an important aspect of stealth technology. This paper reviews contemporary developments in this discipline, with particular emphasis on IR signature prediction from aerospace vehicles. The role of atmosphere in IR signature analysis, and relation between IR signature level and target susceptibility are illustrated. Also, IR signature suppression systems and countermeasure techniques are discussed, to highlight their effectiveness and implications in terms of penalties.

  8. Unraveling the luminescence signatures of chemical defects in polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lihua; Tran, Huan Doan; Wang, Chenchen; Ramprasad, Rampi, E-mail: rampi.ramprasad@uconn.edu [Department of Materials Science and Engineering, Institute of Materials Science, University of Connecticut, 97 North Eagleville Road, Storrs, Connecticut 06269 (United States)

    2015-09-28

    Chemical defects in polyethylene (PE) can deleteriously downgrade its electrical properties and performance. Although these defects usually leave spectroscopic signatures in terms of characteristic luminescence peaks, it is nontrivial to make unambiguous assignments of the peaks to specific defect types. In this work, we go beyond traditional density functional theory calculations to determine intra-defect state transition and charge recombination process derived emission and absorption energies in PE. By calculating the total energy differences of the neutral defect at excited and ground states, the emission energies from intra-defect state transition are obtained, reasonably explaining the photoluminescence peaks in PE. In order to study the luminescence emitted in charge recombination processes, we characterize PE defect levels in terms of thermodynamic and optical charge transition levels that involve total energy calculations of neutral and charged defects. Calculations are performed at several levels of theory including those involving (semi)local and hybrid electron exchange-correlation functionals, and many-body perturbation theory. With these critical elements, the emission energies are computed and further used to clarify and confirm the origins of the observed electroluminescence and thermoluminescence peaks.

  9. HD 80606: searching for the chemical signature of planet formation

    Science.gov (United States)

    Saffe, C.; Flores, M.; Buccino, A.

    2015-10-01

    Context. Binary systems with similar components are ideal laboratories that allow several physical processes to be tested, such as the possible chemical pattern imprinted by the planet formation process. Aims: We explore the probable chemical signature of planet formation in the remarkable binary system HD 80606-HD 80607. The star HD 80606 hosts a giant planet with ~4 MJup detected by both transit and radial velocity techniques, which is one of the most eccentric planets detected to date. We study condensation temperature Tc trends of volatile and refractory element abundances to determine whether there is a depletion of refractories, which could be related to the terrestrial planet formation. Methods: We carried out a high-precision abundance determination in both components of the binary system via a line-by-line, strictly differential approach. First, we used the Sun as a reference and then we used HD 80606. The stellar parameters Teff, log g, [Fe/H] and vturb were determined by imposing differential ionization and excitation equilibrium of Fe I and Fe II lines, with an updated version of the program FUNDPAR, together with plane-parallel local thermodynamic equilibrium (LTE) ATLAS9 model atmospheres and the MOOG code. Then, we derived detailed abundances of 24 different species with equivalent widths and spectral synthesis with the program MOOG. The chemical patterns were compared with the solar-twins Tc trends of Meléndez et al. (2009, AJ, 704, L66) and with a sample of solar-analogue stars with [Fe/H] ~ +0.2 dex from Neves et al. (2009, A&A, 497, 563). The Tc trends were also compared mutually between both stars of the binary system. Results: From the study of Tc trends, we concluded that the stars HD 80606 and HD 80607 do not seem to be depleted in refractory elements, which is different for the case of the Sun. Then, following the interpretation of Meléndez et al. (2009), the terrestrial planet formation would have been less efficient in the components of

  10. Millimeter-wave imaging of thermal and chemical signatures

    International Nuclear Information System (INIS)

    Development of a passive millimeter-wave (mm-wave) system is described for remotely mapping thermal and chemical signatures of process effluents with application to arms control and nonproliferation. Because a large amount of heat is usually dissipated in the air or waterway as a by-product of most weapons of mass destruction facilities, remote thermal mapping may be used to detect concealed or open facilities of weapons of mass destruction. We have developed a focal-plane mm-wave imaging system to investigate the potential of thermal mapping. Results of mm-wave images obtained with a 160-GHz radiometer system are presented for different target scenes simulated in the laboratory. Chemical and nuclear facilities may be identified by remotely measuring molecular signatures of airborne molecules emitted from these facilities. We have developed a filterbank radiometer to investigate the potential of passive spectral measurements. Proof of principle is presented by measuring the HDO spectral line at 80.6 GHz with a 4-channel 77-83 GHz radiometer

  11. Chemical signature study of tupiguarani ceramic tradition from Central region of the Rio Grande do Sul state, Brazil; Estudo de assinaturas quimicas em ceramica da tradicao tupiguarani da regiao central do estado do Rio Grande do Sul, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Bona, Irene Akemy Tomiyoshi

    2006-07-01

    In this work a model based on experimental results using chemical composition data of the pottery sherds applied to Spearmann's no parametric test, principal component analysis and discriminant analysis, was applied. The samples are soils and Tupiguarani Tradition pottery sherd from the central area of the Rio Grande do Sul State. The chemical elements , Al, Ba, Ca, Cr, Fe, K Mn, Pb, Rb, S, Si, Sr, Ti, V and Zn were determined by energy dispersive X-ray fluorescence (EDXFR) while Ce, Cu, Gd, La, Nd, Pr, Sm, Th and Y by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) techniques. Relationships among the pottery characteristics, studied sites and sherd dispersion in the several sites were proposed. Indications of chemical signature of the small pottery with function to go or not to the fire were observed. The largest dispersion is of small pottery with surface treatment no corrugated. The potteries chemical fingerprints from Ijui River, Ibicui-Vacacai Mirim River and Jacui River were verified. (author)

  12. Identification of chemical signatures of gunshot residues in different fabrics

    International Nuclear Information System (INIS)

    The modern forensic science goes hand in hand with scientific research. The forensic scientists are faced every day with many cases requiring the analysis of residues from firing gun (gunshot residues). This works describes the development of a methodology to determine chemical signatures of shots from a firearm, by measuring the concentrations of Pb, Ba e Sb in the residues from these shots deposited near the entrance hole of bullets, based on the technique with high resolution inductively coupled plasma mass spectrometry (HRICP-MS). Shots were performed on five types of target-fabrics and collected testimonies from regions close to the entrance hole of projectiles. The results showed that the method enabled us to identify and distinguish the residues of the .38 caliber revolver and pistols .40 and 9mm caliber. The use of ternary graphs as a tool for data analysis helped to identify specific patterns of distribution of blank samples and gunshot residues deposited after firing revolvers and pistols. The methodology enabled the assignment of the origin of the shot through the confirmation of the residues collected also from the hands of shooters. As a result the methodology in police procedures and aims to add a valuable contribution to forensic investigations. (author)

  13. Effect of Weather on the Predicted PMN Landmine Chemical Signature for Kabul, Afghanistan

    Energy Technology Data Exchange (ETDEWEB)

    WEBB, STEPHEN W.; PHELAN, JAMES M.

    2002-11-01

    Buried landmines are often detected through the chemical signature in the air above the soil surface by mine detection dogs. Environmental processes play a significant role in the chemical signature available for detection. Due to the shallow burial depth of landmines, the weather influences the release of chemicals from the landmine, transport through the soil to the surface, and degradation processes in the soil. The effect of weather on the landmine chemical signature from a PMN landmine was evaluated with the T2TNT code for Kabul, Afghanistan. Results for TNT and DNT gas-phase and soil solid-phase concentrations are presented as a function of time of the day and time of the year.

  14. A systematic method for the targeted discovery of chemical attribution signatures: application to isopropyl bicyclophosphate production.

    Science.gov (United States)

    Mazzitelli, Carolyn L; Re, Michael A; Reaves, Melissa A; Acevedo, Carlos A; Straight, Stephen D; Chipuk, Joseph E

    2012-08-01

    Potential attribution signatures for the synthesis of a highly toxic bicyclophosphate, 4-isopropyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxide (Isopropyl Bicyclophosphate or IPBCP) were discovered using a trilateral synthetic, analytical, and statistical approach. Initially, five synthetic routes were confirmed to successfully produce IPBCP using a range of reaction solvents, reactant ratios, and reaction temperatures. Experimental design principles were subsequently used to guide a formal study specifically aimed at discovering attribution signatures that could be used to differentiate forensic samples. A comparison of three-dimensional scatter plots comprised of the detected ions, their relative retention times (RRTs) and intensities (from LC-MS analyses) identified: (1) signatures that were unique to a synthetic route; (2) signatures associated with a combination of synthetic route and reaction solvent; (3) signatures related to reaction solvent, and (4) signatures associated with reagent source. Top level analysis revealed that the majority of the signatures are related to the synthetic route or a combination of the synthetic route and reaction solvent. Deeper analysis utilizing high resolution mass spectrometry (HRMS) and MS(n) revealed that most of the signatures stem from impurities in the reagents or byproducts formed from incomplete reactions between the reagents used in a given synthetic route. Finally, a subsequent validation study was performed to assess the presence and absence of the key route dependent signatures. PMID:22725731

  15. Chemical Industry Bandwidth Study

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2006-12-01

    The Chemical Bandwidth Study provides a snapshot of potentially recoverable energy losses during chemical manufacturing. The advantage of this study is the use of "exergy" analysis as a tool for pinpointing inefficiencies.

  16. Preserving chemical signatures of primordial star formation in the first low-mass stars

    CERN Document Server

    Ji, Alexander P; Bromm, Volker

    2015-01-01

    We model early star forming regions and their chemical enrichment by Population III (Pop III) supernovae with nucleosynthetic yields featuring high [C/Fe] ratios and pair-instability supernova (PISN) signatures. We aim to test how well these chemical abundance signatures are preserved in the gas prior to forming the first long-lived low-mass stars (or second-generation stars). Our results show that second-generation stars can retain the nucleosynthetic signature of their Pop III progenitors, even in the presence of nucleosynthetically normal Pop III core-collapse supernovae. We find that carbon-enhanced metal-poor stars are likely second-generation stars that form in minihaloes. Furthermore, it is likely that the majority of Pop III supernovae produce high [C/Fe] yields. In contrast, metals ejected by a PISN are not concentrated in the first star forming haloes, which may explain the absence of observed PISN signatures in metal-poor stars. We also find that unique Pop III abundance signatures in the gas are q...

  17. Active sampling technique to enhance chemical signature of buried explosives

    Science.gov (United States)

    Lovell, John S.; French, Patrick D.

    2004-09-01

    Deminers and dismounted countermine engineers commonly use metal detectors, ground penetrating radar and probes to locate mines. Many modern landmines have a very low metal content, which severely limits the effectiveness of metal detectors. Canines have also been used for landmine detection for decades. Experiments have shown that canines smell the explosives which are known to leak from most types of landmines. The fact that dogs can detect landmines indicates that vapor sensing is a viable approach to landmine detection. Several groups are currently developing systems to detect landmines by "sniffing" for the ultra-trace explosive vapors above the soil. The amount of material that is available to passive vapor sensing systems is limited to no more than the vapor in equilibrium with the explosive related chemicals (ERCs) distributed in the surface soils over and near the landmine. The low equilibrium vapor pressure of TNT in the soil/atmosphere boundary layer and the limited volume of the boundary layer air imply that passive chemical vapor sensing systems require sensitivities in the picogram range, or lower. ADA is working to overcome many of the limitations of passive sampling methods, by the use of an active sampling method that employs a high-powered (1,200+ joules) strobe lamp to create a highly amplified plume of vapor and/or ERC-bearing fine particulates. Initial investigations have demonstrated that this approach can amplify the detectability of TNT by two or three orders of magnitude. This new active sampling technique could be used with any suitable explosive sensor.

  18. Chemical Signatures of and Precursors to Fractures Using Fluid Inclusion Stratigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Lorie M. Dilley

    2011-03-30

    Enhanced Geothermal Systems (EGS) are designed to recover heat from the subsurface by mechanically creating fractures in subsurface rocks. Open or recently closed fractures would be more susceptible to enhancing the permeability of the system. Identifying dense fracture areas as well as large open fractures from small fracture systems will assist in fracture stimulation site selection. Geothermal systems are constantly generating fractures (Moore, Morrow et al. 1987), and fluids and gases passing through rocks in these systems leave small fluid and gas samples trapped in healed microfractures. These fluid inclusions are faithful records of pore fluid chemistry. Fluid inclusions trapped in minerals as the fractures heal are characteristic of the fluids that formed them, and this signature can be seen in fluid inclusion gas analysis. This report presents the results of the project to determine fracture locations by the chemical signatures from gas analysis of fluid inclusions. With this project we hope to test our assumptions that gas chemistry can distinguish if the fractures are open and bearing production fluids or represent prior active fractures and whether there are chemical signs of open fracture systems in the wall rock above the fracture. Fluid Inclusion Stratigraphy (FIS) is a method developed for the geothermal industry which applies the mass quantification of fluid inclusion gas data from drill cuttings and applying known gas ratios and compositions to determine depth profiles of fluid barriers in a modern geothermal system (Dilley, 2009; Dilley et al., 2005; Norman et al., 2005). Identifying key gas signatures associated with fractures for isolating geothermal fluid production is the latest advancement in the application of FIS to geothermal systems (Dilley and Norman, 2005; Dilley and Norman, 2007). Our hypothesis is that peaks in FIS data are related to location of fractures. Previous work (DOE Grant DE-FG36-06GO16057) has indicated differences in the

  19. Dissolved black carbon in Antarctic lakes: Chemical signatures of past and present sources

    Science.gov (United States)

    Khan, Alia L.; Jaffé, Rudolf; Ding, Yan; McKnight, Diane M.

    2016-06-01

    The perennially ice-covered, closed-basin lakes in the McMurdo Dry Valleys, Antarctica, serve as sentinels for understanding the fate of dissolved black carbon from glacial sources in aquatic ecosystems. Here we show that dissolved black carbon can persist in freshwater and saline surface waters for thousands of years, while preserving the chemical signature of the original source materials. The ancient brines of the lake bottom waters have retained dissolved black carbon with a woody chemical signature, representing long-range transport of black carbon from wildfires. In contrast, the surface waters are enriched in contemporary black carbon from fossil fuel combustion. Comparison of samples collected 25 years apart from the same lake suggests that the enrichment in anthropogenic black carbon is recent. Differences in the chemical composition of dissolved black carbon among the lakes are likely due to biogeochemical processing such as photochemical degradation and sorption on metal oxides.

  20. HD 41641: A classical δ Sct-type pulsator with chemical signatures of an Ap star

    Science.gov (United States)

    Escorza, A.; Zwintz, K.; Tkachenko, A.; Van Reeth, T.; Ryabchikova, T.; Neiner, C.; Poretti, E.; Rainer, M.; Michel, E.; Baglin, A.; Aerts, C.

    2016-04-01

    Context. Among the known groups of pulsating stars, δ Sct stars are one of the least understood. Theoretical models do not predict the oscillation frequencies that observations reveal. Complete asteroseismic studies are necessary to improve these models and better understand the internal structure of these targets. Aims: We study the δ Sct star HD 41641 with the ultimate goal of understanding its oscillation pattern. Methods: The target was simultaneously observed by the CoRoT space telescope and the HARPS high-resolution spectrograph. The photometric data set was analyzed with the software package PERIOD04, while FAMIAS was used to analyze the line profile variations. The method of spectrum synthesis was used for spectroscopically determining the fundamental atmospheric parameters and individual chemical abundances. Results: A total of 90 different frequencies was identified and analyzed. An unambiguous identification of the azimuthal order of the surface geometry could only be provided for the dominant p-mode, which was found to be a nonradial prograde mode with m = +1. Using Teff and log g, we estimated the mass, radius, and evolutionary stage of HD 41641. We find HD 41641 to be a moderately rotating, slightly evolved δ Sct star with subsolar overall atmospheric metal content and unexpected chemical peculiarities. Conclusions: HD 41641 is a pure δ Sct pulsator with p-mode frequencies in the range from 10 d-1 to 20 d-1. This pulsating star presents chemical signatures of an Ap star and rotational modulation due to surface inhomogeneities, which we consider indirect evidence of the presence of a magnetic field. The CoRoT space mission was developed and operated by the French space agency CNES, with participation of ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany, and Spain.This work uses ground-based spectroscopic observations made with the HARPS instrument at the 3.6 m-ESO telescope (La Silla, Chile) under the Large Program 185.D-0056.

  1. 3D numerical simulation of the transport of chemical signature compounds from buried landmines

    Science.gov (United States)

    Irrazabal, Maik; Borrero, Ernesto; Briano, Julio G.; Castro, Miguel; Hernandez, Samuel P.

    2005-06-01

    The transport of the chemical signature compounds from buried landmines in a three-dimensional (3D) array has been numerically modeled using the finite-volume technique. Compounds such as trinitrotoluene, dinitrotoluene, and their degradation products, are semi volatile and somewhat soluble in water. Furthermore, they can strongly adsorb to the soil and undergo chemical and biological degradation. Consequently, the spatial and temporal concentration distributions of such chemicals depend on the mobility of the water and gaseous phases, their molecular and mechanical diffusion, adsorption characteristics, soil water content, compaction, and environmental factors. A 3D framework is required since two-dimensional (2D) symmetry may easily fade due to terrain topography: non-flat surfaces, soil heterogeneity, or underground fractures. The spatial and temporal distribution of the chemical-signature-compounds, in an inclined grid has been obtained. The fact that the chemicals may migrate horizontally, giving higher surface concentrations at positions not directly on top of the objects, emphasizes the need for understanding the transport mechanism when a chemical detector is used. Deformation in the concentration contours after rainfall is observed in the inclined surface and is attributed to both: the advective flux, and to the water flux at the surface caused by the slope. The analysis of the displacements in the position of the maximum concentrations at the surface, respect to the actual location of the mine, in an inclined system, is presented.

  2. Detection of Landmine Signature using SAW-based Polymer-coated Chemical Sensor

    Directory of Open Access Journals (Sweden)

    O. K. Kannan

    2004-07-01

    Full Text Available The explosive charge within a landmine is the source for a mixture of chemical vapours that form a distinctive chemical signature indicative of a landmine. The concentrations of these compounds in the air over landmines is extremely low (parts-per-trillion or lower, well below the minimum detection limits of most field-portable chemical sensors. This paper describes a portable  surface acoustic wave-based polymer-coated sensor for the detection of hidden explosives. The sensitivity and selectivity of polymer-based sensors depend on several factors including the chemo-selective coating used, the physical properties of the vapour(s of interest, the selected transducers, and the operating conditions. The polymer-based sensor was calibrated in the  laboratory using the explosive vapour generator. The preliminary results indicated that the carbowax 1000 could be a very good chemical interface to sense low levels of chemical signature of explosive material. Response for 50 ppb of TNT vapours was observed to be 400 Hz for an exposure of 2 min.

  3. Environmental fate and transport of chemical signatures from buried landmines -- Screening model formulation and initial simulations

    Energy Technology Data Exchange (ETDEWEB)

    Phelan, J.M.; Webb, S.W.

    1997-06-01

    The fate and transport of chemical signature molecules that emanate from buried landmines is strongly influenced by physical chemical properties and by environmental conditions of the specific chemical compounds. Published data have been evaluated as the input parameters that are used in the simulation of the fate and transport processes. A one-dimensional model developed for screening agricultural pesticides was modified and used to simulate the appearance of a surface flux above a buried landmine, estimate the subsurface total concentration, and show the phase specific concentrations at the ground surface. The physical chemical properties of TNT cause a majority of the mass released to the soil system to be bound to the solid phase soil particles. The majority of the transport occurs in the liquid phase with diffusion and evaporation driven advection of soil water as the primary mechanisms for the flux to the ground surface. The simulations provided herein should only be used for initial conceptual designs of chemical pre-concentration subsystems or complete detection systems. The physical processes modeled required necessary simplifying assumptions to allow for analytical solutions. Emerging numerical simulation tools will soon be available that should provide more realistic estimates that can be used to predict the success of landmine chemical detection surveys based on knowledge of the chemical and soil properties, and environmental conditions where the mines are buried. Additional measurements of the chemical properties in soils are also needed before a fully predictive approach can be confidently applied.

  4. Simulation of the environmental fate and transport of chemical signatures from buried landmines

    Energy Technology Data Exchange (ETDEWEB)

    Phelan, J.M.; Webb, S.W.

    1998-03-01

    The fate and transport of chemical signature molecules that emanate from buried landmines is strongly influenced by physical chemical properties and by environmental conditions of the specific chemical compounds. Published data have been evaluated as the input parameters that are used in the simulation of the fate and transport processes. A one-dimensional model developed for screening agricultural pesticides was modified and used to simulate the appearance of a surface flux above a buried landmine and estimate the subsurface total concentration. The physical chemical properties of TNT cause a majority of the mass released to the soil system to be bound to the solid phase soil particles. The majority of the transport occurs in the liquid phase with diffusion and evaporation driven advection of soil water as the primary mechanisms for the flux to the ground surface. The simulations provided herein should only be used for initial conceptual designs of chemical pre-concentration subsystems or complete detection systems. The physical processes modeled required necessary simplifying assumptions to allow for analytical solutions. Emerging numerical simulation tools will soon be available that should provide more realistic estimates that can be used to predict the success of landmine chemical detection surveys based on knowledge of the chemical and soil properties, and environmental conditions where the mines are buried. Additional measurements of the chemical properties in soils are also needed before a fully predictive approach can be confidently applied.

  5. Nature's chemical signatures in human olfaction: a foodborne perspective for future biotechnology.

    Science.gov (United States)

    Dunkel, Andreas; Steinhaus, Martin; Kotthoff, Matthias; Nowak, Bettina; Krautwurst, Dietmar; Schieberle, Peter; Hofmann, Thomas

    2014-07-01

    The biocatalytic production of flavor naturals that determine chemosensory percepts of foods and beverages is an ever challenging target for academic and industrial research. Advances in chemical trace analysis and post-genomic progress at the chemistry-biology interface revealed odor qualities of nature's chemosensory entities to be defined by odorant-induced olfactory receptor activity patterns. Beyond traditional views, this review and meta-analysis now shows characteristic ratios of only about 3 to 40 genuine key odorants for each food, from a group of about 230 out of circa 10 000 food volatiles. This suggests the foodborn stimulus space has co-evolved with, and roughly match our circa 400 olfactory receptors as best natural agonists. This perspective gives insight into nature's chemical signatures of smell, provides the chemical odor codes of more than 220 food samples, and beyond addresses industrial implications for producing recombinants that fully reconstruct the natural odor signatures for use in flavors and fragrances, fully immersive interactive virtual environments, or humanoid bioelectronic noses. PMID:24939725

  6. Digital "Testimonio" as a Signature Pedagogy for Latin@ Studies

    Science.gov (United States)

    Benmayor, Rina

    2012-01-01

    This article proposes the curricular integration of digital "testimonio" as a "signature" pedagogy in Latin@ Studies. The "testimonio" tradition of urgent narratives and the creative multimedia languages of digital storytelling--text, voice, image, and sound--invite historically marginalized subjects, especially younger generations, to author and…

  7. CHEMICAL SIGNATURES OF THE FIRST GALAXIES: CRITERIA FOR ONE-SHOT ENRICHMENT

    International Nuclear Information System (INIS)

    We utilize metal-poor stars in the local, ultra-faint dwarf galaxies (UFDs; L tot ≤ 105 L ☉) to empirically constrain the formation process of the first galaxies. Since UFDs have much simpler star formation histories than the halo of the Milky Way, their stellar populations should preserve the fossil record of the first supernova (SN) explosions in their long-lived, low-mass stars. Guided by recent hydrodynamical simulations of first galaxy formation, we develop a set of stellar abundance signatures that characterize the nucleosynthetic history of such an early system if it was observed in the present-day universe. Specifically, we argue that the first galaxies are the product of chemical 'one-shot' events, where only one (long-lived) stellar generation forms after the first, Population III, SN explosions. Our abundance criteria thus constrain the strength of negative feedback effects inside the first galaxies. We compare the stellar content of UFDs with these one-shot criteria. Several systems (Ursa Major II, and also Coma Berenices, Bootes I, Leo IV, Segue 1) largely fulfill the requirements, indicating that their high-redshift predecessors did experience strong feedback effects that shut off star formation. We term the study of the entire stellar population of a dwarf galaxy for the purpose of inferring details about the nature and origin of the first galaxies 'dwarf galaxy archaeology'. This will provide clues to the connection of the first galaxies, the surviving, metal-poor dwarf galaxies, and the building blocks of the Milky Way.

  8. A SIGNATURE OF CHEMICAL SEPARATION IN THE COOLING LIGHT CURVES OF TRANSIENTLY ACCRETING NEUTRON STARS

    Energy Technology Data Exchange (ETDEWEB)

    Medin, Zach [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Cumming, Andrew, E-mail: zmedin@lanl.gov, E-mail: cumming@physics.mcgill.ca [Department of Physics, McGill University, 3600 rue University, Montreal, QC H3A 2T8 (Canada)

    2014-03-01

    We show that convection driven by chemical separation can significantly affect the cooling light curves of accreting neutron stars after they go into quiescence. We calculate the thermal relaxation of the neutron star ocean and crust including the thermal and compositional fluxes due to convection. After the inward propagating cooling wave reaches the base of the neutron star ocean, the ocean begins to freeze, driving chemical separation. The resulting convection transports heat inward, giving much faster cooling of the surface layers than found assuming the ocean cools passively. The light curves including convection show a rapid drop in temperature weeks after outburst. Identifying this signature in observed cooling curves would constrain the temperature and composition of the ocean as well as offer a real time probe of the freezing of a classical multicomponent plasma.

  9. A SIGNATURE OF CHEMICAL SEPARATION IN THE COOLING LIGHT CURVES OF TRANSIENTLY ACCRETING NEUTRON STARS

    International Nuclear Information System (INIS)

    We show that convection driven by chemical separation can significantly affect the cooling light curves of accreting neutron stars after they go into quiescence. We calculate the thermal relaxation of the neutron star ocean and crust including the thermal and compositional fluxes due to convection. After the inward propagating cooling wave reaches the base of the neutron star ocean, the ocean begins to freeze, driving chemical separation. The resulting convection transports heat inward, giving much faster cooling of the surface layers than found assuming the ocean cools passively. The light curves including convection show a rapid drop in temperature weeks after outburst. Identifying this signature in observed cooling curves would constrain the temperature and composition of the ocean as well as offer a real time probe of the freezing of a classical multicomponent plasma

  10. A signature of chemical separation in the cooling curves of transiently accreting neutron stars

    CERN Document Server

    Medin, Zach

    2013-01-01

    We show that convection driven by chemical separation can significantly affect the cooling curves of accreting neutron stars after they go into quiescence. We calculate the thermal relaxation of the neutron star ocean and crust including the thermal and compositional fluxes due to convection. After the inward propagating cooling wave reaches the base of the neutron star ocean, the ocean begins to freeze, driving chemical separation. The resulting convection transports heat inward, giving much faster cooling of the surface layers than found assuming the ocean cools passively. The light curves including convection show a rapid drop in temperature weeks after outburst. Identifying this signature in observed cooling curves would constrain the temperature and composition of the ocean as well as offer a real time probe of the freezing of a classical multicomponent plasma.

  11. Organic Chemical Attribution Signatures for the Sourcing of a Mustard Agent and Its Starting Materials.

    Science.gov (United States)

    Fraga, Carlos G; Bronk, Krys; Dockendorff, Brian P; Heredia-Langner, Alejandro

    2016-05-17

    Chemical attribution signatures (CAS) are being investigated for the sourcing of chemical warfare (CW) agents and their starting materials that may be implicated in chemical attacks or CW proliferation. The work reported here demonstrates for the first time trace impurities from the synthesis of tris(2-chloroethyl)amine (HN3) that point to the reagent and the specific reagent stocks used in the synthesis of this CW agent. Thirty batches of HN3 were synthesized using different combinations of commercial stocks of triethanolamine (TEA), thionyl chloride, chloroform, and acetone. The HN3 batches and reagent stocks were then analyzed for impurities by gas chromatography/mass spectrometry. All the reagent stocks had impurity profiles that differentiated them from one another. This was demonstrated by building classification models with partial least-squares discriminant analysis (PLSDA) and obtaining average stock classification errors of 2.4, 2.8, 2.8, and 11% by cross-validation for chloroform (7 stocks), thionyl chloride (3 stocks), acetone (7 stocks), and TEA (3 stocks), respectively, and 0% for a validation set of chloroform samples. In addition, some reagent impurities indicative of reagent type were found in the HN3 batches that were originally present in the reagent stocks and presumably not altered during synthesis. More intriguing, impurities in HN3 batches that were apparently produced by side reactions of impurities unique to specific TEA and chloroform stocks, and thus indicative of their use, were observed. PMID:27116337

  12. Organic Chemical Attribution Signatures for the Sourcing of a Mustard Agent and Its Starting Materials

    Energy Technology Data Exchange (ETDEWEB)

    Fraga, Carlos G.; Bronk, Krys; Dockendorff, Brian P.; Heredia-Langner, Alejandro

    2016-05-17

    Chemical attribution signatures (CAS) are being investigated for the sourcing of chemical warfare (CW) agents and their starting materials that may be implicated in chemical attacks or CW proliferation. The work reported here demonstrates for the first time trace impurities produced during the synthesis of tris(2-chloroethyl)amine (HN3) that point to specific reagent stocks used in the synthesis of this CW agent. Thirty batches of HN3 were synthesized using different combinations of commercial stocks of triethanolamine (TEA), thionyl chloride, chloroform, and acetone. The HN3 batches and reagent stocks were then analyzed for impurities by gas chromatography/mass spectrometry. Reaction-produced impurities indicative of specific TEA and chloroform stocks were exclusively discovered in HN3 batches made with those reagent stocks. In addition, some reagent impurities were found in the HN3 batches that were presumably not altered during synthesis and believed to be indicative of reagent type regardless of stock. Supervised classification using partial least squares discriminant analysis (PLSDA) on the impurity profiles of chloroform samples from seven stocks resulted in an average classification error by cross-validation of 2.4%. A classification error of zero was obtained using the seven-stock PLSDA model on a validation set of samples from an arbitrarily selected chloroform stock. In a separate analysis, all samples from two of seven chloroform stocks that were purposely not modeled had their samples matched to a chloroform stock rather than assigned a “no class” classification.

  13. Solvent Extraction of Chemical Attribution Signature Compounds from Painted Wall Board: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, Jon H.; Colburn, Heather A.

    2009-10-29

    This report summarizes work that developed a robust solvent extraction procedure for recovery of chemical attribution signature (CAS) compound dimethyl methyl phosphonate (DMMP) (as well as diethyl methyl phosphonate (DEMP), diethyl methyl phosphonothioate (DEMPT), and diisopropyl methyl phosphonate (DIMP)) from painted wall board (PWB), which was selected previously as the exposed media by the chemical attribution scientific working group (CASWG). An accelerated solvent extraction approach was examined to determine the most effective method of extraction from PWB. Three different solvent systems were examined, which varied in solvent strength and polarity (i.e., 1:1 dichloromethane : acetone,100% methanol, and 1% isopropanol in pentane) with a 1:1 methylene chloride : acetone mixture having the most robust and consistent extraction for four original target organophosphorus compounds. The optimum extraction solvent was determined based on the extraction efficiency of the target analytes from spiked painted wallboard as determined by gas chromatography x gas chromatography mass spectrometry (GCxGC-MS) analysis of the extract. An average extraction efficiency of approximately 60% was obtained for these four compounds. The extraction approach was further demonstrated by extracting and detecting the chemical impurities present in neat DMMP that was vapor-deposited onto painted wallboard tickets.

  14. Contribution of species-specific chemical signatures to soil organic matter in Kohala, HI.

    Science.gov (United States)

    Stewart, C. E.; Amatangelo, K.; Neff, J. C.

    2008-12-01

    Soil organic matter (SOM) inherits much of its chemical structure from the dominant vegetation, including phenolic (lignin-derived), aromatic, and aliphatic (cutin and wax-derived) compounds. The Hawaiian fern species Dicranopteris decomposes more slowly than the angiosperm, Cheirodendron due to high concentrations of recalcitrant C compounds. These aliphatic fern leaf waxes are well-preserved and may comprise a large portion of the recalcitrant organic matter in these soils. Our objective was to determine the chemical signature of fern and angiosperm vegetation types and trace the preservation or loss of those compounds into the soil. We collected live tissue, litter, roots, and soil (tannin-derivatives. There was a general decrease of lignin-derived phenolic compounds from live to litter to soils and an increase in more recalcitrant, aromatic and aliphatic C. Recalcitrant fern-derived cutin and leaf waxes (alkene and alkanes structures) were evident in the soils, but clear species differences were not observed. Although ferns contain distinct lipid and wax-derived compounds, soils developed under fern do not appear to accumulate these compounds in SOM.

  15. Implementation of algorithms to discriminate chemical/biological airbursts from high explosive airbursts utilizing acoustic signatures

    Science.gov (United States)

    Hohil, Myron E.; Desai, Sachi; Morcos, Amir

    2006-05-01

    The Army is currently developing acoustic sensor systems that will provide extended range surveillance, detection, and identification for force protection and tactical security. A network of such sensors remotely deployed in conjunction with a central processing node (or gateway) will provide early warning and assessment of enemy threats, near real-time situational awareness to commanders, and may reduce potential hazards to the soldier. In contrast, the current detection of chemical/biological (CB) agents expelled into a battlefield environment is limited to the response of chemical sensors that must be located within close proximity to the CB agent. Since chemical sensors detect hazardous agents through contact, the sensor range to an airburst is the key-limiting factor in identifying a potential CB weapon attack. The associated sensor reporting latencies must be minimized to give sufficient preparation time to field commanders, who must assess if an attack is about to occur, has occurred, or if occurred, the type of agent that soldiers might be exposed to. The long-range propagation of acoustic blast waves from heavy artillery blasts, which are typical in a battlefield environment, introduces a feature for using acoustics and other sensor suite technologies for the early detection and identification of CB threats. Employing disparate sensor technologies implies that warning of a potential CB attack can be provided to the solider more rapidly and from a safer distance when compared to current conventional methods. Distinct characteristics arise within the different airburst signatures because High Explosive (HE) warheads emphasize concussive and shrapnel effects, while chemical/biological warheads are designed to disperse their contents over immense areas, therefore utilizing a slower burning, less intensive explosion to mix and distribute their contents. Highly reliable discrimination (100%) has been demonstrated at the Portable Area Warning Surveillance System

  16. Microbiota-based Signature of Gingivitis Treatments: A Randomized Study.

    Science.gov (United States)

    Huang, Shi; Li, Zhen; He, Tao; Bo, Cunpei; Chang, Jinlan; Li, Lin; He, Yanyan; Liu, Jiquan; Charbonneau, Duane; Li, Rui; Xu, Jian

    2016-01-01

    Plaque-induced gingivitis can be alleviated by various treatment regimens. To probe the impacts of various anti-gingivitis treatments on plaque microflora, here a double blinded, randomized controlled trial of 91 adults with moderate gingivitis was designed with two anti-gingivitis regimens: the brush-alone treatment and the brush-plus-rinse treatment. In the later group, more reduction in both Plaque Index (TMQHI) and Gingival Index (mean MGI) at Day 3, Day 11 and Day 27 was evident, and more dramatic changes were found between baseline and other time points for both supragingival plaque microbiota structure and salivary metabonomic profiles. A comparison of plaque microbiota changes was also performed between these two treatments and a third dataset where 50 subjects received regimen of dental scaling. Only Actinobaculum, TM7 and Leptotrichia were consistently reduced by all the three treatments, whereas the different microbial signatures of the three treatments during gingivitis relieve indicate distinct mechanisms of action. Our study suggests that microbiota based signatures can serve as a valuable approach for understanding and potentially comparing the modes of action for clinical treatments and oral-care products in the future. PMID:27094556

  17. An Approach for Assessing the Signature Quality of Various Chemical Assays when Predicting the Culture Media Used to Grow Microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, Aimee E.; Sego, Landon H.; Webb-Robertson, Bobbie-Jo M.; Kreuzer, Helen W.; Anderson, Richard M.; Unwin, Stephen D.; Weimar, Mark R.; Tardiff, Mark F.; Corley, Courtney D.

    2013-02-01

    We demonstrate an approach for assessing the quality of a signature system designed to predict the culture medium used to grow a microorganism. The system was comprised of four chemical assays designed to identify various ingredients that could be used to produce the culture medium. The analytical measurements resulting from any combination of these four assays can be used in a Bayesian network to predict the probabilities that the microorganism was grown using one of eleven culture media. We evaluated combinations of the signature system by removing one or more of the assays from the Bayes network. We measured and compared the quality of the various Bayes nets in terms of fidelity, cost, risk, and utility, a method we refer to as Signature Quality Metrics

  18. Dissecting the chemical interactions and substrate structural signatures governing RNA polymerase II trigger loop closure by synthetic nucleic acid analogues

    DEFF Research Database (Denmark)

    Xu, Liang; Butler, Kyle Vincent; Chong, Jenny; Wengel, Jesper; Kool, Eric T; Wang, Dong

    2014-01-01

    The trigger loop (TL) of RNA polymerase II (Pol II) is a conserved structural motif that is crucial for Pol II catalytic activity and transcriptional fidelity. The TL remains in an inactive open conformation when the mismatched substrate is bound. In contrast, TL switches from an inactive open...... remains elusive. Here we employed synthetic nucleotide analogues as 'chemical mutation' tools coupling with α-amanitin transcription inhibition assay to systematically dissect the key chemical interactions and structural signatures governing the substrate-coupled TL closure in Saccharomyces cerevisiae Pol...

  19. An orthologous transcriptional signature differentiates responses towards closely related chemicals in Arabidopsis thaliana and brassica napus

    Science.gov (United States)

    Herbicides are structurally diverse chemicals that inhibit plant-specific targets, however their off-target and potentially differentiating side-effects are less well defined. In this study, genome-wide expression profiling based on Affymetrix AtH1 arrays was used to identify dis...

  20. Searching for Chemical Signatures of Multiple Stellar Populations in the Old, Massive Open Cluster NGC 6791

    CERN Document Server

    Bragaglia, A; Carretta, E; Gratton, R G; Lucatello, S; Bernath, P F; Brooke, J S A; Ram, R S

    2014-01-01

    Galactic open and globular clusters (OCs, GCs) appear to inhabit separate regions of the age-mass plane. However, the transition between them is not easily defined because there is some overlap between high-mass, old OCs and low-mass, young GCs. We are exploring the possibility of a clear-cut separation between OCs and GCs using an abundance feature that has been found so far only in GCs: (anti)correlations between light elements. Among the coupled abundance trends, the Na-O anticorrelation is the most widely studied. These anticorrelations are the signature of self-enrichment, i.e., of a formation mechanism that implies multiple generations of stars. Here we concentrate on the old, massive, metal-rich OC NGC 6791. We analyzed archival Keck/HIRES spectra of 15 NGC 6791 main sequence turn-off and evolved stars, concentrating on the derivation of C, N, O, and Na abundances. We also used WIYN/Hydra spectra of 21 evolved stars (one is in common). Given the spectral complexity of the very metal-rich NGC 6791 stars...

  1. Infrared signatures of Bacillus bacteria: Clear IR distinctions between sporulated and vegetative cells with chemical assignments

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Timothy J.; Williams, Stephen D.; Valentine, Nancy B.; Su, Yin-Fong; Kreuzer-Martin, Helen W.; Wahl, Karen L.; Forrester, Joel B.

    2009-05-08

    This paper highlights the distinctions between the infrared (IR) absorption spectra of vegetative versus sporulated Bacillus bacteria. It is observed that there are unique signatures clearly associated with either the sporulated or the vegetative state, and that vegetative cells (and associated debris) can contribute to the spore spectra. A distinct feature at ~1739 cm-1 appears to be unique to vegetative cell spectra, and can also be used as an indicator of vegetative cells or cell debris in the spore spectra. The data indicate the band is caused by a phospholipid carbonyl bond and are consistent with, but do not prove it to be, either phosphatidyl ethanolamine (PE) or phosphatidyl glycerol (PG), the two major classes of phospholipids found in vegetative cells of Bacillus species. The endospore spectra show characteristic peaks at 1441, 1277, and 1015 cm-1 along with a distinct quartet of peaks at 766, 725, 701, and 659 cm-1. These are clearly associated with calcium dipicolinate trihydrate, CaDP•3H2O. We emphasize that the spore peaks, especially the quartet, arise from the calcium dipicolinate trihydrate and not from dipicolinic acid or other dipicolinate hydrate salts. The CaDP•3H2O vibrational peaks and the effects of hydration were studied using quantum chemistry in the PQS software package. The quartet is associated with many motions including contributions from the Ca2+ counterion and hydration waters including Ca-O-H bends, H2O-Ca-O torsions and O-C-O bends. The 1441 and 1015 cm-1 modes are planar pyridine modes with the 1441 mode primarily a ring C-N stretch and the 1015 mode primarily a ring C-C stretch.

  2. Infrared Signatures of Bacillus Bacteria: Clear IR Distinctions Between Sporulated and Vegetative Cells with Chemical Assighments

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Timothy J.; Williams, Stephen D.; Valentine, Nancy B.; Su, Yin-Fong; Kreuzer-Martin, Helen W.; Wahl, Karen L.; Forrester, Joel B.

    2009-05-04

    This paper highlights the distinctions between the infrared (IR) absorption spectra of vegetative versus sporulated Bacillus bacteria. It is observed that there are unique signatures clearly associated with either the sporulated or the vegetative state, and that vegetative cells (and associated debris) can contribute to the spore spectra. A distinct feature at ~1739 cm-1 appears to be unique to vegetative cell spectra, and can also be used as an indicator of vegetative cells or cell debris in the spore spectra. The data indicate the band is caused by a phospholipid carbonyl bond and are consistent with, but do not prove it to be, either phosphatidyl ethanolamine (PE) or phosphatidyl glycerol (PG), the two major classes of phospholipids found in vegetative cells of Bacillus species. The endospore spectra show characteristic peaks at 1441, 1277, and 1015 cm-1 along with a distinct quartet of peaks at 766, 725, 701, and 659 cm-1. These are clearly associated with calcium dipicolinate trihydrate, CaDP•3H2O. We emphasize that the spore peaks, especially the quartet, arise from the calcium dipicolinate trihydrate and not from dipicolinic acid or other dipicolinate hydrate salts. The CaDP•3H2O vibrational peaks and the effects of hydration were studied using quantum chemistry in the PQS software package. The quartet is associated with many motions including contributions from the Ca2+ counterion and hydration waters including Ca-O-H bends, H2O-Ca-O torsions and O-C-O bends. The 1441 and 1015 cm-1 modes are planar pyridine modes with the 1441 mode primarily a ring C-N stretch and the 1015 mode primarily a ring C-C stretch.

  3. Planet signatures and effect of the chemical evolution of the Galactic thin-disk stars

    CERN Document Server

    Spina, Lorenzo; Ramírez, Ivan

    2016-01-01

    Context: Studies based on high-precision abundance determinations revealed that chemical patterns of solar twins are characterised by the correlation between the differential abundances relative to the Sun and the condensation temperatures (Tc) of the elements. It has been suggested that the origin of this relation is related to the chemical evolution of the Galactic disk, but other processes, associated with the presence of planets around stars, might also be involved. Aims: We analyse HIRES spectra of 14 solar twins and the Sun to provide new insights on the mechanisms that can determine the relation between [X/H] and Tc. Methods: Our spectroscopic analysis produced stellar parameters (Teff, log g, [Fe/H], and $\\xi$), ages, masses, and abundances of 22 elements (C, O, Na, Mg, Al, Si, S, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, and Ba). We used these determinations to place new constraints on the chemical evolution of the Galactic disk and to verify whether this process alone can explain the diff...

  4. Studying the variability in the Raman signature of writing pen inks.

    Science.gov (United States)

    Braz, André; López-López, María; García-Ruiz, Carmen

    2014-10-14

    This manuscript aims to study the inter and intra brand, model and batch variability in the Raman spectral signature among modern pen inks that will help forensic document examiners during the interpretation process. Results showed that most oil-based samples have similar Raman signatures that are characteristic of the Crystal Violet dye, independently of the brand. Exception was the Pilot samples that use Victoria Pure Blue BO instead. This small inter-brand variability makes oil-based pens difficult to discriminate by brand. On the contrary, gel and liquid-based samples use different colorants such as Rhodamine B, Copper Phthalocyanine, Ethyl Violet and Victoria Blue B. No particular pattern was observed regarding the colorants used by each brand, except the Pilot samples that were the only brand using the Victoria Blue B dye, which is a clear distinct feature. Additionally, the intra-brand variability was also large among gel-based Pilot samples. The small spectral differences observed among several batches of Bic Crystal Medium samples demonstrated that changes were introduced in their chemical formula over the years. The intra-batch variability was small and no spectral differences were observed within batches. This manuscript demonstrates the potential of Raman spectroscopy for discriminating pens inks from different brands and models and even, batches. Additionally, the main colorants used in modern pens were also identified. PMID:25447172

  5. Identification of volatile chemical signatures from plastic explosives by SPME-GC/MS and detection by ion mobility spectrometry.

    Science.gov (United States)

    Lai, Hanh; Leung, Alfred; Magee, Matthew; Almirall, José R

    2010-04-01

    This study demonstrates the use of solid-phase microextraction (SPME) to extract and pre-concentrate volatile signatures from static air above plastic explosive samples followed by detection using ion mobility spectrometry (IMS) optimized to detect the volatile, non-energetic components rather than the energetic materials. Currently, sample collection for detection by commercial IMS analyzers is conducted through swiping of suspected surfaces for explosive particles and vapor sampling. The first method is not suitable for sampling inside large volume areas, and the latter method is not effective because the low vapor pressure of some explosives such as RDX and PETN make them not readily available in the air for headspace sampling under ambient conditions. For the first time, headspace sampling and detection of Detasheet, Semtex H, and C-4 is reported using SPME-IMS operating under one universal setting with limits of detection ranging from 1.5 to 2.5 ng for the target volatile signatures. The target signature compounds n-butyl acetate and the taggant DMNB are associated with untagged and tagged Detasheet explosives, respectively. Cyclohexanone and DMNB are associated with tagged C-4 explosives. DMNB is associated with tagged Semtex H explosives. Within 10 to 60 s of sampling, the headspace inside a glass vial containing 1 g of explosive, more than 20 ng of the target signatures can be extracted by the SPME fiber followed by IMS detection. PMID:20229010

  6. HD 41641: a classical $\\delta$ Sct-type pulsator with chemical signatures of an Ap star

    CERN Document Server

    Escorza, A; Tkachenko, A; Van Reeth, T; Ryabchikova, T; Neiner, C; Poretti, E; Rainer, M; Michel, E; Baglin, A; Aerts, C

    2016-01-01

    Among the known groups of pulsating stars, $\\delta$ Sct stars are one of the least understood. The theoretical models do not predict the oscillation frequencies that observations reveal. Complete asteroseismic studies are necessary to improve these models and better understand the internal structure of these targets. In this paper, we study the $\\delta$ Sct star HD 41641 with the ultimate goal of understanding its oscillation pattern. The target has been simultaneously observed by the CoRoT space telescope and the HARPS high-resolution spectrograph. The photometric data set was analyzed with the software package PERIOD04, while FAMIAS was used to analyze the line profile variations. The method of spectrum synthesis was used for spectroscopically determining the fundamental atmospheric parameters and the individual chemical abundances. A total of 90 different frequencies was identified and analyzed. An unambiguous identification of the azimuthal order of the surface geometry could be provided for the dominant ...

  7. Crustal processes cause adakitic chemical signatures in syn-collision magmatism from SE Iran

    Science.gov (United States)

    Allen, Mark; Kheirkhah, Monireh; Neill, Iain

    2015-04-01

    We report new elemental and Nd-Sr isotopic analyses for Late Cenozoic intrusive and extrusive rocks emplaced in SE Iran as part of the wider syn-collision magmatic province within the Turkish-Iranian Plateau. The sample sites are near the town of Dehaj in Kerman Province. Most of the rocks are from stocks and batholiths, interpreted as the roots of central volcanoes. Age controls are not precise, but the rocks are likely to be Late Miocene-Quaternary in age. Basaltic to andesitic lavas crop out nearby; their relationships to the intrusive rocks are uncertain. Geochemically, the entire range of rocks from basalt lavas through to rhyolitic intrusives ranges from 51-71 wt.% silica and isotopic signatures are similar to Bulk Earth, without any clear evidence for large-scale crustal contamination. The basaltic to andesitic lavas appear to have variable and often high La/Yb and Sr/Y such that they range from calc-alkaline arc-like rocks to adakitic compositions depending on the degree of fractionation. The intrusive rocks seem to form a separate suite, with clear indications of increasing Sr/Y and Dy/Yb with fractionation. Previous interpretations relate adakitic magmatism to Tethyan oceanic slab break-off and slab melting beneath the collision zone. However, as the 'adakitic signature' is increasingly apparent in more evolved magmas, at least in the intrusives, adakite generation is more likely to have occurred during melt evolution from an initial low Sr/Y and low La/Yb parent. This parental melt may have been similar in starting composition to proposed non-adakitic basaltic melts from elsewhere in the collision zone. The high Sr/Yb and La/Yb signatures are best explained by the suppression of plagioclase fractionation by high magmatic water contents, promoting incompatible behaviour of Sr. Conversely, Y and Yb are compatible during amphibole and garnet fractionation at crustal or uppermost mantle levels. Rather than a localised slab break-off or melting effect, the

  8. A novel data mining method to identify assay-specific signatures in functional genomic studies

    Directory of Open Access Journals (Sweden)

    Guidarelli Jack W

    2006-08-01

    Full Text Available Abstract Background: The highly dimensional data produced by functional genomic (FG studies makes it difficult to visualize relationships between gene products and experimental conditions (i.e., assays. Although dimensionality reduction methods such as principal component analysis (PCA have been very useful, their application to identify assay-specific signatures has been limited by the lack of appropriate methodologies. This article proposes a new and powerful PCA-based method for the identification of assay-specific gene signatures in FG studies. Results: The proposed method (PM is unique for several reasons. First, it is the only one, to our knowledge, that uses gene contribution, a product of the loading and expression level, to obtain assay signatures. The PM develops and exploits two types of assay-specific contribution plots, which are new to the application of PCA in the FG area. The first type plots the assay-specific gene contribution against the given order of the genes and reveals variations in distribution between assay-specific gene signatures as well as outliers within assay groups indicating the degree of importance of the most dominant genes. The second type plots the contribution of each gene in ascending or descending order against a constantly increasing index. This type of plots reveals assay-specific gene signatures defined by the inflection points in the curve. In addition, sharp regions within the signature define the genes that contribute the most to the signature. We proposed and used the curvature as an appropriate metric to characterize these sharp regions, thus identifying the subset of genes contributing the most to the signature. Finally, the PM uses the full dataset to determine the final gene signature, thus eliminating the chance of gene exclusion by poor screening in earlier steps. The strengths of the PM are demonstrated using a simulation study, and two studies of real DNA microarray data – a study of

  9. Chemical signature of two Permian volcanic ash deposits within a bentonite bed from Melo, Uruguay.

    Science.gov (United States)

    Calarge, Liane M; Meunier, Alain; Lanson, Bruno; Formoso, Milton L L

    2006-09-01

    A Permian bentonite deposit at Melo, Uruguay is composed of a calcite-cemented sandstone containing clay pseudomorphs of glass shards (0-0.50 m) overlying a pink massive clay deposit (0.50-2.10 m). The massive bed is composed of two layers containing quartz and smectite or pure smectite respectively. The smectite is remarkably homogeneous throughout the profile: it is a complex mixed layer composed of three layer types whose expandability with ethylene glycol (2EG 1EG or 0EG sheets in the interlayer zone which correspond to low-, medium- and high-charge layers respectively) varies with the cation saturating the interlayer zone. The smectite homogeneity through the profile is the signature of an early alteration process in a lagoonal water which was over saturated with respect to calcite. Compaction during burial has made the bentonite bed a K-depleted closed system in which diagenetic illitization was inhibited. Variations in major, REE and minor element abundances throughout the massive clay deposit suggest that it originated from two successive ash falls. The incompatible element abundances are consistent with that of a volcanic glass fractionated from a rhyolite magma formed in a subduction/collision geological context. PMID:16936941

  10. Chemical Signatures of Interstellar Dusts Preserved in Primitive Chondrites and Inner Planets of the Solar System

    Science.gov (United States)

    Yin, Qing-Zhu

    2002-01-01

    We show that the inheritance of interstellar materials by the solar system is not only documented by the presence of presolar grains, various isotopic anomalies, but also expressed in the chemical element distribution in the inner solar system. Additional information is contained in the original extended abstract.

  11. Country-specific chemical signatures of persistent environmental compounds in breast milk

    DEFF Research Database (Denmark)

    Krysiak-Baltyn, Konrad; Toppari, J.; Skakkebaek, N.E.;

    2010-01-01

    , exhibits much lower incidences of these disorders. The reasons behind the observed trends are unexplained, but environmental endocrine disrupting chemicals (EDCs) that affect foetal testis development are probably involved. Levels of persistent chemicals in breast milk can be considered a proxy......Recent reports have confirmed a worldwide increasing trend of testicular cancer incidence, and a conspicuously high prevalence of this disease and other male reproductive disorders, including cryptorchidism and hypospadias, in Denmark. In contrast, Finland, a similarly industrialized Nordic country...... in testicular cancer or in adversely affecting development of the foetal testis in humans and animals, our findings reinforce the view that environmental exposure to EDCs may explain some of the temporal and between-country differences in incidence of male reproductive disorders....

  12. Exclusion of cosmic rays in protoplanetary disks. II. Chemical gradients and observational signatures

    Energy Technology Data Exchange (ETDEWEB)

    Cleeves, L. Ilsedore; Bergin, Edwin A.; Adams, Fred C. [Department of Astronomy, University of Michigan, 1085 South University Avenue, Ann Arbor, MI 48109 (United States)

    2014-10-20

    The chemical properties of protoplanetary disks are especially sensitive to their ionization environment. Sources of molecular gas ionization include cosmic rays (CRs), stellar X-rays, and short-lived radionuclides, each of which varies with location in the disk. This behavior leads to a significant amount of chemical structure, especially in molecular ion abundances, which is imprinted in their submillimeter rotational line emission. Using an observationally motivated disk model, we make predictions for the dependence of chemical abundances on the assumed properties of the ionizing field. We calculate the emergent line intensity for abundant molecular ions and simulate sensitive observations with the Atacama Large Millimeter/Sub-millimeter Array (ALMA) for a disk at D = 100 pc. The models readily distinguish between high ionization rates (ζ ≳ 10{sup –17} s{sup –1} per H{sub 2}) and below, but it becomes difficult to distinguish between low ionization models when ζ ≲ 10{sup –19} s{sup –1}. We find that H{sub 2}D{sup +} emission is not detectable for sub-interstellar CR rates with ALMA (6h integration), and that N{sub 2}D{sup +} emission may be a more sensitive tracer of midplane ionization. HCO{sup +} traces X-rays and high CR rates (ζ{sub CR} ≳ 10{sup –17} s{sup –1}), and provides a handle on the warm molecular ionization properties where CO is present in the gas. Furthermore, species like HCO{sup +}, which emits from a wide radial region and samples a large gradient in temperature, can exhibit ring-like emission as a consequence of low-lying rotational level de-excitation near the star. This finding highlights a scenario where rings are not necessarily structural or chemical in nature, but simply a result of the underlying line excitation properties.

  13. Exclusion of cosmic rays in protoplanetary disks. II. Chemical gradients and observational signatures

    International Nuclear Information System (INIS)

    The chemical properties of protoplanetary disks are especially sensitive to their ionization environment. Sources of molecular gas ionization include cosmic rays (CRs), stellar X-rays, and short-lived radionuclides, each of which varies with location in the disk. This behavior leads to a significant amount of chemical structure, especially in molecular ion abundances, which is imprinted in their submillimeter rotational line emission. Using an observationally motivated disk model, we make predictions for the dependence of chemical abundances on the assumed properties of the ionizing field. We calculate the emergent line intensity for abundant molecular ions and simulate sensitive observations with the Atacama Large Millimeter/Sub-millimeter Array (ALMA) for a disk at D = 100 pc. The models readily distinguish between high ionization rates (ζ ≳ 10–17 s–1 per H2) and below, but it becomes difficult to distinguish between low ionization models when ζ ≲ 10–19 s–1. We find that H2D+ emission is not detectable for sub-interstellar CR rates with ALMA (6h integration), and that N2D+ emission may be a more sensitive tracer of midplane ionization. HCO+ traces X-rays and high CR rates (ζCR ≳ 10–17 s–1), and provides a handle on the warm molecular ionization properties where CO is present in the gas. Furthermore, species like HCO+, which emits from a wide radial region and samples a large gradient in temperature, can exhibit ring-like emission as a consequence of low-lying rotational level de-excitation near the star. This finding highlights a scenario where rings are not necessarily structural or chemical in nature, but simply a result of the underlying line excitation properties.

  14. Chemical signatures of rocky accretion in a young solar-type star

    Science.gov (United States)

    Spina, Lorenzo

    2015-12-01

    It is well known that newly formed planetary systems undergo processes of orbital reconfiguration and planetary migration. As a result, planets or proto-planetary objects may accrete onto the central star, being fused and mixed into its external layers. If the accreted mass is sufficiently large and the star has a sufficiently thin convective envelope, such events may result in a modification of the chemical composition of the stellar photosphere in an observable way, enhancing it with elements that were abundant in the accreted mass. Recently, the Gaia-ESO Survey observations of the 10-20 Myr old Gamma Velorum cluster have enabled the identification of a star significantly enriched in iron with respect to other cluster members. In this seminar I will present a further investigation of the abundance pattern of this star, showing that its chemical anomaly is not limited to iron, but is also present in all the refractory elements whose abundances are correlated with the condensation temperature. This finding strongly supports the hypothesis of a recent accretion of rocky material.

  15. CHEMICAL SIGNATURE OF A MAJOR MERGER IN THE EARLY FORMATION OF THE SMALL MAGELLANIC CLOUD

    International Nuclear Information System (INIS)

    The formation history of the Small Magellanic Cloud (SMC) is unraveled based on the results of our new chemical evolution models constructed for the SMC, highlighting the observed anomaly in the age-metallicity relation for star clusters in the SMC. We first propose that evidence of a major merger is imprinted in the age-metallicity relation as a dip in [Fe/H]. Our models predict that the major merger with a mass ratio of 1:1 to 1:4 occurred at ∼7.5 Gyr ago, with a good reproduction of the abundance distribution function of field stars in the SMC. Furthermore, our models predict a relatively large scatter in [Mg/Fe] for -1.4 ≤ [Fe/H] ≤ -1.1 as a reflection of a looping feature resulting from the temporally inverse progress of chemical enrichment, which can be tested against future observational results. Given that the observed velocity dispersion (∼30 km s-1) of the SMC is much smaller than that (∼160 km s-1) of the Galactic halo, our finding strongly implies that the predicted merger event happened in a small group environment that was far from the Galaxy and contained a number of small gas-rich dwarfs comparable to the SMC. This theoretical view is extensively discussed in the framework that considers a connection with the formation history of the Large Magellanic Cloud.

  16. The Application of Spatial Signature Analysis to Electrical Test Data: Validation Study

    Energy Technology Data Exchange (ETDEWEB)

    Gleason, S.S.; Karnowski, T.P.; Lakhani, F.; Tobin, K.W.

    1999-03-15

    This paper presents the results of the Spatial Signature Analysis (SSA) Electrical-test (e-test) validation study that was conducted between February and June, 1998. SSA is an automated procedure developed by researchers at the Oak Ridge National Laboratory to address the issue of intelligent data reduction while providing feedback on current manufacturing processes. SSA was initially developed to automate the analysis of optical defect data. Optical defects can form groups, or clusters, which may have a distinct shape. These patterns can reveal information about the manufacturing process. Optical defect SSA uses image processing algorithms and a classifier system to interpret and identify these patterns, or signatures. SSA has been extended to analyze and interpret electrical test data. The algorithms used for optical defect SSA have been adapted and applied to e-test binmaps. An image of the binmap is created, and features such as geometric and invariant moments are extracted and presented to a pair-wise, fuzzy, k-NN classifier. The classifier itself was prepared by manually training, which consists of storing example signatures of interest in a library, then executing an automated process which treats the examples as prototype signatures. The training process includes a procedure for automatically determining which features are most relevant to each class. The evaluation was performed by installing the SSA software as a batch process at three SEMATECH member company sites. Feedback from member company representatives was incorporated and classifiers were built to automatically assign labels to the binmap signatures. The three sites produced memory devices (DRAM) and microprocessors in a mature process fabrication environment. For all of these products, 5,620 signatures that encompassed approximately 552 wafers were human-classified and analyzed. The performance of the SSA E-test system indicates that the approach was successful in reliably classifying binmap

  17. Multi-study integration of brain cancer transcriptomes reveals organ-level molecular signatures.

    Directory of Open Access Journals (Sweden)

    Jaeyun Sung

    Full Text Available We utilized abundant transcriptomic data for the primary classes of brain cancers to study the feasibility of separating all of these diseases simultaneously based on molecular data alone. These signatures were based on a new method reported herein--Identification of Structured Signatures and Classifiers (ISSAC--that resulted in a brain cancer marker panel of 44 unique genes. Many of these genes have established relevance to the brain cancers examined herein, with others having known roles in cancer biology. Analyses on large-scale data from multiple sources must deal with significant challenges associated with heterogeneity between different published studies, for it was observed that the variation among individual studies often had a larger effect on the transcriptome than did phenotype differences, as is typical. For this reason, we restricted ourselves to studying only cases where we had at least two independent studies performed for each phenotype, and also reprocessed all the raw data from the studies using a unified pre-processing pipeline. We found that learning signatures across multiple datasets greatly enhanced reproducibility and accuracy in predictive performance on truly independent validation sets, even when keeping the size of the training set the same. This was most likely due to the meta-signature encompassing more of the heterogeneity across different sources and conditions, while amplifying signal from the repeated global characteristics of the phenotype. When molecular signatures of brain cancers were constructed from all currently available microarray data, 90% phenotype prediction accuracy, or the accuracy of identifying a particular brain cancer from the background of all phenotypes, was found. Looking forward, we discuss our approach in the context of the eventual development of organ-specific molecular signatures from peripheral fluids such as the blood.

  18. Chemical signature of two Permian volcanic ash deposits within a bentonite bed from Melo, Uruguay

    Directory of Open Access Journals (Sweden)

    Liane M. Calarge

    2006-09-01

    Full Text Available A Permian bentonite deposit at Melo, Uruguay is composed of a calcite-cemented sandstone containing clay pseudomorphs of glass shards (0-0.50 m overlying a pink massive clay deposit (0.50-2.10m. The massive bed is composed of two layers containing quartz and smectite or pure smectite respectively. The smectite is remarkably homogeneous throughout the profile: it is a complex mixed layer composed of three layer types whose expandability with ethylene glycol (2EG 1EG or 0EG sheets in the interlayer zone which correspond to low-, medium- and high-charge layers respectively varies with the cation saturating the interlayer zone. The smectite homogeneity through the profile is the signature of an early alteration process in a lagoonal water which was over saturated with respect to calcite. Compaction during burial has made the bentonite bed a K-depleted closed system in which diagenetic illitization was inhibited. Variations in major, REE and minor element abundances throughout the massive clay deposit suggest that it originated from two successive ash falls. The incompatible element abundances are consistent with that of a volcanic glass fractionated from a rhyolite magma formed in a subduction/collision geological context.Um depósito Permiano de bentonita em Melo, Uruguai,é composto por um arenito com cimento calcítico contendo pseudomorfos de argila sobre detritos vítreos(0-0.50 m superpostos a um deposito maciço de argila rosado (0.50-2.10 m. A camada maciça é composta por dois níveis contendo quartzo e esmectita ou esmectita pura, respectivamente. A homogeneidade de esmectita ao longo do perfil é notável: trata-se de um interestratificado composto de três tipos de camadas, cuja expansibilidade com etileno-glicol (folhas 2EG, 1EG ou 0EG na zona interfoliar correspondentes a camadas com baixa, média e alta carga, respectivamente variam com o tipo de cátion que satura a zona interfoliar. A homogeneidade da esmectita ao longo do perfil

  19. Chemical signatures of life in modern stromatolites from Lake Alchichica, Mexico. Applications for the search of life on Mars

    Science.gov (United States)

    Navarro, Karina F.; Navarro-Gonzalez, Rafael; Alcocer, Javier; Escobar, Elva; Morales, Pedro; Cienfuegos, Edith; Coll, Patrice; Raulin, Francois; Stalport, Fabien; Cabane, Michel; Person, Alain; McKay, Chris

    ,5-dimethylfuran, 4-methylpyridine, ethylbenzene, dimethylbenzene, styrene, methylbenze-neamine, 2,4-hexadienal, phenol, 3-methyl-2-cyclopenten-1-one, benzonitrile, cyclopropyliden-emethylbenzene, 2,3-dihydro-1-H-indene, 1-methylethenylbenzene, 3-methylphenol, and 1-propenyl-benzene. The carbon isotopic composition of the organic fraction of the stromatolites is deter-mined by a δ 13 C=-24.28 whereas the inorganic fraction, hydromagnesite, is determined by a δ 13 C=5.86. Our data shows two interesting chemical signatures that can used to detect extant life in Martian carbonates: (1) organics are not oxidized by mineral matrix during TV-MS and TV-GC-MS analysis; and (2) distinctive carbon isotopic fractionation occurs in the or-ganic and inorganic fraction of stromatolites. Future work should center on studying fossilized stromatolites to determine if these chemical signatures are lost with time. References: Ehlmann, B.L., Mustard, J.F., Murchie, S.L. Poulet, F., Bishop, J.L., Brown, A.J., Calvin, W.M., Clark, R.N., Des Marais, D.J., Milliken, R.E., Roach, L.H., Roush, T.L., Swayze, G.A., and Wray, J.J.: 2008, Orbital identification of carbonate-bearing rocks on Mars. Science 322, 1828-1832. Escobar-Briones, E., Alcocer, J., Cienfuegos, E., and Morales P.: 1998, Carbon stable isotopes ratios of pelagic and litoral communities in Alchichica crater-lake, Mexico, Internat J Salt Lake Res 7, 345-355. Falcón, L.I., Escobar-Briones, E., and Romero, D.: 2002, Nitrogen fixation patterns displayed by cyanobacterial consortia in Alchichica crater-lake, Mexico, Hydrobiol 467, 71-78. Navarro-González, R., Navarro, K.F., de la Rosa, J., Molina, P., Iñiguez, E., Miranda, L.D., a n Morales, P., Cienfuegos, E., Coll, P., Raulin, F., Amils, R. and McKay, C.P.: 2006. The limitations on organic detection in Mars-like soils by thermal volatilization-gas chromatography-MS and their implications for the Viking results. Proc Natl Acad Sci USA 103, 16089-16094. Navarro-González, R., Iñiguez, E., de

  20. Pilot study of automated bullet signature identification based on topography measurements and correlations.

    Science.gov (United States)

    Chu, Wei; Song, John; Vorburger, Theodore; Yen, James; Ballou, Susan; Bachrach, Benjamin

    2010-03-01

    A procedure for automated bullet signature identification is described based on topography measurements using confocal microscopy and correlation calculation. Automated search and retrieval systems are widely used for comparison of firearms evidence. In this study, 48 bullets fired from six different barrel manufacturers are classified into different groups based on the width class characteristic for each land engraved area of the bullets. Then the cross-correlation function is applied both for automatic selection of the effective correlation area, and for the extraction of a 2D bullet profile signature. Based on the cross-correlation maximum values, a list of top ranking candidates against a ballistics signature database of bullets fired from the same model firearm is developed. The correlation results show a 9.3% higher accuracy rate compared with a currently used commercial system based on optical reflection. This suggests that correlation results can be improved using the sequence of methods described here. PMID:20102451

  1. Outer Belt Radial Transport Signatures in Drift Phase Structure - Case Studies

    Science.gov (United States)

    O'Brien, Paul; Green, Janet; Fennell, Joseph; Claudepierre, Seth; Roeder, James; Kwan, Betty; Mulligan Skov, Tamitha

    2016-07-01

    During geomagnetic storms, the Earth's outer radiation belt experiences enhanced radial transport. Different modes of radial transport have different temporal signatures in the particle phase-space density on timescales shorter than a drift period. We use such drift phase structure in time series particle flux observations to identify transport signatures of impulsive and oscillatory drift resonant transport. We perform multiple case studies of geomagnetic storms using particle flux taken near geostationary orbit. We estimate the radial diffusion coefficients from the drift phase structures. We show how these radial diffusion coefficients derived from particle data compare to transport coefficients deduced from wave observations.

  2. Mantle amphibole control on arc and within-plate chemical signatures: Quaternary lavas from Kurdistan Province, Iran

    Science.gov (United States)

    Kheirkhah, M.; Allen, M. B.; Neill, I.; Emami, M. H.; McLeod, C.

    2012-04-01

    New analyses of Quaternary lavas from Kurdistan Province in west Iran shed light on the nature of collision zone magmatism. The rocks are from the Turkish-Iranian plateau within the Arabia-Eurasia collision. Compositions are typically basanite, hawaiite and alkali basalt. Sr-Nd isotope values are close to BSE, which is similar to Quaternary alkali basalts of NW Iran, but distinct from a depleted source melting under Mount Ararat. The chemical signatures suggests variable melting of two distinct sources. One inferred source produced melts with La/Nb from~3.5 to~1.2, which we model as the result of depletion of amphibole during ≤1% melting in the garnet stability field. We infer phlogopite in the source of potassic lavas from Takab. Lithosphere delamination or slab break-off mechanisms for triggering melting are problematic, as the lithosphere is~150-200km thick. It is possible that the negative dT/dP section of the amphibole peridotite solidus was crossed as a result of lithospheric thickening in the collision zone. This explanation is conditional upon the mantle source being weakly hydrated and so only containing a small proportion of amphibole, which can be exhausted during small degrees of partial melting. Our model maybe viable for other magmatic areas within orogenic plateaux, e.g. northern Tibet. Depletion of mantle amphibole may also help explain larger scale transitions from arc to within-plate chemistry in orogens, such as the Palaeogene Arabia-Eurasia system.

  3. Physical and chemical signatures of a developing anticyclonic eddy in the Leeuwin Current, eastern Indian Ocean

    OpenAIRE

    Paterson, Harriet L.; Feng, Ming; Waite, Anya M.; Gomis, Damià; Beckley, Lynnath E.; Holliday, David; Thompson, Peter A

    2008-01-01

    A multidisciplinary cruise aboard the R/V Southern Surveyor was conducted in May 2006 to sample a developing anticyclonic eddy of the Leeuwin Current off Western Australia. The eddy formed from a meander of the Leeuwin Current in mid-April 2006 and remained attached to the current until mid-August. In this study, a combination of satellite data (altimeter, sea surface temperature, and chlorophyll a) and shipboard measurements (acoustic Doppler current profiler and conductivity-temperature-dep...

  4. Multivariate analysis of laser-induced breakdown spectroscopy chemical signatures for geomaterial classification

    International Nuclear Information System (INIS)

    A large suite of natural carbonate, fluorite and silicate geological materials was studied using laser-induced breakdown spectroscopy (LIBS). Both single- and double-pulse LIBS spectra were acquired using close-contact benchtop and standoff (25 m) LIBS systems. Principal components analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were used to identify the distinguishing characteristics of the geological samples and to classify the materials. Excellent discrimination was achieved with all sample types using PLS-DA and several techniques for improving sample classification were identified. The laboratory double-pulse LIBS system did not provide any advantage for sample classification over the single-pulse LIBS system, except in the case of the soil samples. The standoff LIBS system provided comparable results to the laboratory systems. This work also demonstrates how PCA can be used to identify spectral differences between similar sample types based on minor impurities.

  5. Neural Signatures of Phonetic Learning in Adulthood: A Magnetoencephalography Study

    OpenAIRE

    Zhang, Yang; Kuhl, Patricia K.; Imada, Toshiaki; Iverson, Paul; Pruitt, John; Stevens, Erica B.; Kawakatsu, Masaki; Tohkura, Yoh'ichi; Nemoto, Iku

    2009-01-01

    The present study used magnetoencephalography (MEG) to examine perceptual learning of American English /r/ and /l/ categories by Japanese adults who had limited English exposure. A training software program was developed based on the principles of infant phonetic learning, featuring systematic acoustic exaggeration, multi-talker variability, visible articulation, and adaptive listening. The program was designed to help Japanese listeners utilize an acoustic dimension relevant for phonemic cat...

  6. Hot subluminous stars: On the Search for Chemical Signatures of their Genesis

    Science.gov (United States)

    Hirsch, Heiko Andreas

    2009-10-01

    , however, is still under debate. While the cooler sdBs can be analyzed with relatively simple LTE model atmospheres, the hot sdOs require much more sophisticated NLTE calculations. The large effort required for sdO analyses resulted in a relatively low number of paper on the subject, when compared with the numerous publications on sdB stars. Besides a few detailed studies of individuell objects, the ≈ 50 stars analyzed by Ströer et al. (2007) is the only extensive work on sdOs. They explained the helium poor sdOs as progeny of the sdB stars. But for the helium enriched sdOs, no definite statement about their evolutionary status could be found. In order to get a large sample of sdOs, this work made use of the Sloan Digital Sky Survey (SDSS), one of the most extensive photometric and spectroscopic surveys in astronomy. About 14000 spectra were classified by visual inspection by means of easily recognizable spectral features. We now have a large database with classificatons of hot stars. The majority of the spectra were classified as white dwarfs, among them a number of previously unknown magnetic white dwarfs. 1500 objects were identified as hot subluminous stars, about 200 of them are sdOs. We determined effective temperatures, surface gravities and atmospheric helium abundances for these objects. Two evolutionary scenarios remain valid options for the sdOs' origin: The merging of two helium white dwarfs and the delayed helium flash of a red giant star ("late hot flasher"). In the first scenario, two low mass white dwarfs in short period orbits lose orbital energy by radiation of gravitational waves. As their orbit shrinks, the less massive one will fill its Roche lobe and get disrupted and accreted on the companion. Unfortunately no detailed calculations of the explosive nucleosynthesis exist for this scenario. The late hot flashers are stars that do not experience the helium core flash until they leave their red giant phase and already evolve towards the white dwarfs

  7. Study of the microdoppler signature of a bicyclist for different directions of approach

    Science.gov (United States)

    Rodriguez-Hervas, Berta; Maile, Michael; Flores, Benjamin C.

    2015-05-01

    The successful implementation of autonomous driving in an urban setting depends on the ability of the environment perception system to correctly classify vulnerable road users such as pedestrians and bicyclists in dense, complex scenarios. Self-driving vehicles include sensor systems such as cameras, lidars, and radars to enable decision making. Among these systems, radars are particularly relevant due to their operational robustness under adverse weather and night light conditions. Classification of pedestrian and car in urban settings using automotive radar has been widely investigated, suggesting that micro-Doppler signatures are useful for target discrimination. Our objective is to analyze and study the micro-Doppler signature of bicyclists approaching a vehicle from different directions in order to establish the basis of a classification criterion to distinguish bicycles from other targets including clutter. The micro-Doppler signature is obtained by grouping individual reflecting points using a clustering algorithm and observing the evolution of all the points belonging to an object in the Doppler domain over time. A comparison is then made with simulated data that uses a kinematic model of bicyclists' movement. The suitability of the micro-Doppler bicyclist signature as a classification feature is determined by comparing it to those belonging to cars and pedestrians approaching the automotive radar system.

  8. Signature molecular descriptor : advanced applications.

    Energy Technology Data Exchange (ETDEWEB)

    Visco, Donald Patrick, Jr. (Tennessee Technological University, Cookeville, TN)

    2010-04-01

    In this work we report on the development of the Signature Molecular Descriptor (or Signature) for use in the solution of inverse design problems as well as in highthroughput screening applications. The ultimate goal of using Signature is to identify novel and non-intuitive chemical structures with optimal predicted properties for a given application. We demonstrate this in three studies: green solvent design, glucocorticoid receptor ligand design and the design of inhibitors for Factor XIa. In many areas of engineering, compounds are designed and/or modified in incremental ways which rely upon heuristics or institutional knowledge. Often multiple experiments are performed and the optimal compound is identified in this brute-force fashion. Perhaps a traditional chemical scaffold is identified and movement of a substituent group around a ring constitutes the whole of the design process. Also notably, a chemical being evaluated in one area might demonstrate properties very attractive in another area and serendipity was the mechanism for solution. In contrast to such approaches, computer-aided molecular design (CAMD) looks to encompass both experimental and heuristic-based knowledge into a strategy that will design a molecule on a computer to meet a given target. Depending on the algorithm employed, the molecule which is designed might be quite novel (re: no CAS registration number) and/or non-intuitive relative to what is known about the problem at hand. While CAMD is a fairly recent strategy (dating to the early 1980s), it contains a variety of bottlenecks and limitations which have prevented the technique from garnering more attention in the academic, governmental and industrial institutions. A main reason for this is how the molecules are described in the computer. This step can control how models are developed for the properties of interest on a given problem as well as how to go from an output of the algorithm to an actual chemical structure. This report

  9. The tsunami signature on a submerged promontory: the case study of the Atacames Promontory, Ecuador

    OpenAIRE

    Ioualalen, Mansour; Ratzov, Gueorgui; Collot, Jean-Yves; Sanclemente, E.

    2011-01-01

    P>Shelf promontories exhibit very specific bathymetric features with regards to tsunamis. Because of their submerged cape morphology, a potential tsunami generated seawards of the promontory will exhibit a specific mode of propagation and coastal impact. To identify this peculiar tsunami signature, the Atacames Promontory, Ecuador, was chosen as a case study (another example is the shelf of the Nile delta, Egypt). The area is tectonically very active, hosts earthquakes among the most powerful...

  10. A predictive toxicogenomics signature to classify genotoxic versus non-genotoxic chemicals in human TK6 cells

    Directory of Open Access Journals (Sweden)

    Andrew Williams

    2015-12-01

    Full Text Available Genotoxicity testing is a critical component of chemical assessment. The use of integrated approaches in genetic toxicology, including the incorporation of gene expression data to determine the DNA damage response pathways involved in response, is becoming more common. In companion papers previously published in Environmental and Molecular Mutagenesis, Li et al. (2015 [6] developed a dose optimization protocol that was based on evaluating expression changes in several well-characterized stress-response genes using quantitative real-time PCR in human lymphoblastoid TK6 cells in culture. This optimization approach was applied to the analysis of TK6 cells exposed to one of 14 genotoxic or 14 non-genotoxic agents, with sampling 4 h post-exposure. Microarray-based transcriptomic analyses were then used to develop a classifier for genotoxicity using the nearest shrunken centroids method. A panel of 65 genes was identified that could accurately classify toxicants as genotoxic or non-genotoxic. In Buick et al. (2015 [1], the utility of the biomarker for chemicals that require metabolic activation was evaluated. In this study, TK6 cells were exposed to increasing doses of four chemicals (two genotoxic that require metabolic activation and two non-genotoxic chemicals in the presence of rat liver S9 to demonstrate that S9 does not impair the ability to classify genotoxicity using this genomic biomarker in TK6cells.

  11. Does the chemical signature of TYC 8442-1036-1 originate from a rotating massive star that died in a faint explosion?

    CERN Document Server

    Cescutti, G; François, P; Chiappini, C; Depagne, E; Christlieb, N; Cortés, C

    2016-01-01

    Context. We have recently investigated the origin of chemical signatures observed in Galactic halo stars by means of a stochastic chemical evolution model. We have found that rotating massive stars are a promising way to explain several signatures observed in these fossil stars. Aims. In the present paper we discuss how the extremely metal-poor halo star TYC 8442-1036-1, for which we have now obtained detailed abundances from VLT-UVES spectra, fits into the framework of our previous work. Methods. We apply a standard 1D LTE analysis to the spectrum of this star. We measure the abundances of 14 chemical elements; for Na, Mg, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni and Zn we compute the abundances using equivalent widths; for C, Sr and Ba we obtain the abundances by means of synthetic spectra generated by MOOG. Results. We find an abundance of [Fe/H]= $-$3.5 $\\pm$0.13 dex based on our high resolution spectrum; this points to an iron content lower by a factor of three (0.5 dex) compared to the one obtained by a low resolu...

  12. A Phenomenographic Study on Chemical Bonding

    Directory of Open Access Journals (Sweden)

    Şenol Şen

    2013-12-01

    Full Text Available This study aims to reveal how students perceive and identify the concept of chemical bonding, and to identify and explain the misconceptions of students on this subject through phenomenographic research method, as well. The present study included 17 2nd grade students who enrolled to Inorganic Chemistry course in the Faculty of Education. Concept maps and lotus blossom technique were used as data collection tools in order to determine the perceptions and definitions of students about chemical bonding. Data analysis results determined the misconceptions of students about chemical bonding classified misconceptions under seven categories, which are, according to the results of the study, physical changes and bonding, ionic bond, formation of chemical bonding, the existence of chemical bonding, covalent bonds, metallic bonds and intermolecular bonding.

  13. Demonstration of spread-on peel-off consumer products for sampling surfaces contaminated with pesticides and chemical warfare agent signatures.

    Science.gov (United States)

    Behringer, Deborah L; Smith, Deborah L; Katona, Vanessa R; Lewis, Alan T; Hernon-Kenny, Laura A; Crenshaw, Michael D

    2014-08-01

    A terrorist attack using toxic chemicals is an international concern. The utility of rubber cement and latex body paint as spray-on/spread-on peel-off collection media for signatures attributable to pesticides and chemical warfare agents from interior building and public transportation surfaces two weeks post-deposition is demonstrated. The efficacy of these media to sample escalator handrail, stainless steel, vinyl upholstery fabric, and wood flooring is demonstrated for two pesticides and eight chemicals related to chemical warfare agents. The chemicals tested are nicotine, parathion, atropine, diisopropyl methylphosphonate, dimethyl methylphosphonate, dipinacolyl methylphosphonate, ethyl methylphosphonic acid, isopropyl methylphosphonic acid, methylphosphonic acid, and thiodiglycol. Amounts of each chemical found are generally greatest when latex body paint is used. Analytes with low volatility and containing an alkaline nitrogen or a sulfur atom (e.g., nicotine and parathion) usually are recovered to a greater extent than the neutral phosphonate diesters and acidic phosphonic acids (e.g., dimethyl methylphosphonate and ethyl methylphosphonic acid). PMID:24835029

  14. Coupled Numerical Study of Turbidity Currents, Internal Hydraulic Jump and Morphological Signatures

    Science.gov (United States)

    Hu, P.; Cao, Z.; He, Z.; Gareth, P.

    2013-12-01

    Abstract: The last two decades have seen intensive experimental and numerical studies of the occurrence condition of internal hydraulic jump in turbidity currents and the induced morphological signatures (Garcia and Parker 1989; Kostic and Parker 2006). Yet there are two critical issues that remain insufficiently or inappropriately addressed. First, depositional turbidity currents are imposed on steep slopes in both flume experiments and numerical cases, exclusively based on a configuration consisting of an upstream sloping portion and a downstream horizontal portion linked by a slope break. This appears physically counterintuitive as steep slope should favour self-accelerating erosional turbidity currents (Parker et al. 1986). The second issue concerns the numerical studies. There exist significant interactions among the current, sediment transport and bed topography. Due to the slope break in bed, the current may experience an internal hydraulic jump, leaving morphological signatures on the bed, which in turn affects the current evolution. Nevertheless, simplified decoupled models are exclusively employed in previous numerical investigations, in which the interactions are either partly or completely ignored without sufficient justification. The present paper aims to address the above-mentioned two issues relevant to the occurrence condition of the internal hydraulic jump and the induced morphological signatures. A recently developed well-balanced coupled numerical model for turbidity currents (Hu et al. 2012) is applied. In contrast to previous studies, erosional turbidity currents will be imposed at the upstream boundary, which is much more typical of the field. The effects of sediment size, bed slope decrease, and upstream and downstream boundary conditions are revealed in detail. In addition, the evolution of turbidity currents over a bed characterized by gradual decrease in slope is also discussed. References Garcia, M. H., and Parker, G. (1989). Experiments

  15. A Fly-Through Mission Strategy Targeting Peptide as a Signature of Chemical Evolution and Possible Life in Enceladus Plumes

    Science.gov (United States)

    Fujishima, Kosuke; Dziomba, Szymon; Takahagi, Wataru; Shibuya, Takazo; Takano, Yoshinori; Guerrouache, Mohamed; Carbonnier, Benjamin; Takai, Ken; Rothschild, Lynn J.; Yano, Hajime

    2016-01-01

    In situ detection of organic molecules in the extraterrestrial environment provides a key step towards better understanding the variety and the distribution of building blocks of life and it may ultimately lead to finding extraterrestrial life within the Solar System. Here we present combined results of two separate experiments that enable us to realize such in situ life signature detection from the deep habitats of the "Ocean World": a hydrothermal reactor experiment simulating complex organic synthesis and a simulated fly-through capture experiment of organic-bearing microparticles using silica aerogels, followed by subsequent analysis. Both experiments employ peptide as a plausible organics existing in Encleadus plume particles produced in its subsurface ocean. Recent laboratory hydrothermal experiments and a theoretical model on silica saturation indicated an on going hydrothermal reactions in subsurface Enceladus ocean. Given the porous chondritic origin of the core, it is likely that organic compounds originated by radiation chemistry such as amino acid precursors could have been provided, leached, and altered through widespread water-rock interactions. By using the same laboratory experimental setup from the latest water-rock interaction study, we performed amino acid polymerization experiments for 144 days and monitored the organic complexity changing over time. So far over 3,000 peaks up to the size of greater than 600 MW were observed through the analysis of capillary electrophoresis time-of-flight mass spectrometry (CE-TOF-MS) with an indication of amino acid derivatives and short peptides. Generally abiotic polymerization of enantiomeric amino acids results in forming stereoisomeric peptides with identical molecular weight and formula as opposed to homochiral biopolymers. Assuming Enceladus plume particles may contain a mixture of stereoisomeric peptides, we were able to distinguish 16 of the 17 stereoisomeric tripeptides as a test sample using

  16. A Phenomenographic Study on Chemical Bonding

    OpenAIRE

    Şenol Şen; Ayhan Yılmaz

    2013-01-01

    This study aims to reveal how students perceive and identify the concept of chemical bonding, and to identify and explain the misconceptions of students on this subject through phenomenographic research method, as well. The present study included 17 2nd grade students who enrolled to Inorganic Chemistry course in the Faculty of Education. Concept maps and lotus blossom technique were used as data collection tools in order to determine the perceptions and definitions of students about chemical...

  17. Numerical study on signatures of atmospheric convective cells in radar images of the ocean

    OpenAIRE

    Ufermann, S.; Romeiser, R.

    1999-01-01

    Current and wind variations at the ocean surface can give rise to a modulation of the sea surface roughness and thus become visible in radar images. The discrimination between radar signatures of oceanic and atmospheric phenomena can be quite difficult, since signatures of different origin can have very similar shapes and magnitudes and are often superimposed upon each other. In this work we employ a numerical radar imaging model for an investigation of typical properties of radar signatures ...

  18. Application of a case–control study design to investigate genotypic signatures of HIV-1 transmission

    Directory of Open Access Journals (Sweden)

    Mota Talia M

    2012-06-01

    Full Text Available Abstract Background The characterization of HIV-1 transmission strains may inform the design of an effective vaccine. Shorter variable loops with fewer predicted glycosites have been suggested as signatures enriched in envelope sequences derived during acute HIV-1 infection. Specifically, a transmission-linked lack of glycosites within the V1 and V2 loops of gp120 provides greater access to an α4β7 binding motif, which promotes the establishment of infection. Also, a histidine at position 12 in the leader sequence of Env has been described as a transmission signature that is selected against during chronic infection. The purpose of this study is to measure the association of the presence of an α4β7 binding motif, the number of N-linked glycosites, the length of the variable loops, and the prevalence of histidine at position 12 with HIV-1 transmission. A case–control study design was used to measure the prevalence of these variables between subtype B and C transmission sequences and frequency-matched randomly-selected sequences derived from chronically infected controls. Results Subtype B transmission strains had shorter V3 regions than chronic strains (p = 0.031; subtype C transmission strains had shorter V1 loops than chronic strains (p = 0.047; subtype B transmission strains had more V3 loop glycosites (p = 0.024 than chronic strains. Further investigation showed that these statistically significant results were unlikely to be biologically meaningful. Also, there was no difference observed in the prevalence of a histidine at position 12 among transmission strains and controls of either subtype. Conclusions Although a genetic bottleneck is observed after HIV-1 transmission, our results indicate that summary characteristics of Env hypothesised to be important in transmission are not divergent between transmission and chronic strains of either subtype. The success of a transmission strain to initiate infection may be a random

  19. The dissolved chemical and isotopic signature downflow the confluence of two large rivers: The case of the Parana and Paraguay rivers

    Science.gov (United States)

    Campodonico, Verena Agustina; García, María Gabriela; Pasquini, Andrea Inés

    2015-09-01

    The Paraná River basin is one of the largest hydrological systems in South America (∼2.6 × 106 km2). Downflow the confluence of tributaries, most large rivers exhibit transverse and longitudinal inhomogeneities that can be detected for tens or even hundreds of kilometers. Concordantly, a noticeable cross-sectional chemical asymmetry in the dissolved load was distinguished in the Middle Paraná River, after the confluence of its main tributaries (i.e., the Paraguay and Upper Paraná rivers). Water chemistry and isotopic signature in three cross-sections along the Middle Paraná River, as well as from main and minor tributaries, and some deep (∼105 m bs) and shallow boreholes (∼15 m bs) located near both river banks, were analyzed in order to define the extent of mixing and identify possible contributions from groundwater discharges. Downflow the confluence of the Upper Paraná and Paraguay rivers a chemical and isotopic asymmetry was observed, mainly through the values of EC, major ions (Ca2+, Na+, Mg2+, Cl- and SO42-), some trace elements (Fe, U, Th, Ba, Sr, As and REE) and stable isotopes (δ18O and δ2H). Toward its western margin, higher elemental concentrations which resembled that of the Paraguay River were measured, whereas at the eastern border, waters were more diluted and preserved the chemical signature of the Upper Paraná River. This variability remained detectable at least until ∼225 km downflow the confluence, where differences between western and eastern margins were less evident. At ∼580 km downflow the confluence, a slight inversion in the transverse chemical asymmetry was observed. This trend switch can be the result of the input of solutes from minor tributaries that reach the main channel from the East and/or may be due to higher groundwater discharges from the East bank. A mass balance model was applied, as a first approach, to estimate the groundwater inflow using the geochemical tracer 222Rn. The results indicate that groundwater

  20. Prediction of engine casing temperature of fighter aircraft for infrared signature studies

    Science.gov (United States)

    Mahulikar, Shripad P.

    1992-04-01

    Prediction of engine casing temperature of combat aircraft for various operating conditions needs modeling of convective and radiative heat flow from the jet pipe to the casing. Radiation modeling which implies modeling of multiple reflections and scattering is done here by the radiance-irradiance approach. The engine layout is approximated by three co-axial cylinders and axially discretized. The shape factors (which account for the directional dependence of radiation heat flow) for various configurations needed in radiation modeling are analytically obtained by a sequence of shape factor algebra from standard configurations. The resulting non-linear algebraic equations of combined convection and radiation heat flow are solved by an iterative technique to give the engine casing temperatures which may be used for infrared signature studies.

  1. Gene expression signatures in CD34+-progenitor-derived dendritic cells exposed to the chemical contact allergen nickel sulfate

    International Nuclear Information System (INIS)

    The detection of the sensitizing potential of chemicals is of great importance to industry. A promising in vitro alternative to the currently applied animal assays for sensitization testing makes use of dendritic cells (DCs) that have the capability to process and present antigens to naive T cells and induce their proliferation. Here, we studied changes in gene expression profiles after exposing DCs to the contact allergen nickel sulfate. CD34+-progenitor-derived DCs, initiated from 3 different donors, were exposed to 60 μM nickel sulfate, during 0.5, 1, 3, 6, 12 and 24 h. cDNA microarrays were used to assess the transcriptional activity of about 11,000 genes. Significant changes in the expression of 283 genes were observed; 178 genes were up-regulated and 93 down-regulated. These genes were involved in metabolism, cell structure, immune response, transcription, signal transduction, transport, and apoptosis. No functional information was found for 74 genes. Real-time RT-PCR was used to confirm the microarray results of 12 genes. In addition, 3 DC maturation markers not present on the microarrays (DEC205, DC LAMP and CCR7) were analyzed using real-time RT-PCR and found to be up-regulated at several time points. Our data indicate that a broad range of biological processes is influenced by nickel. Some processes are clearly linked to the immune response and DC maturation, others may indicate a toxic effect of nickel

  2. The radial metallicity gradients in the Milky Way thick disk as fossil signatures of a primordial chemical distribution

    CERN Document Server

    Curir, A; Spagna, A; Lattanzi, M G; Fiorentin, P Re; Diaferio, A

    2014-01-01

    In this letter we examine the evolution of the radial metallicity gradient induced by secular processes, in the disk of an $N$-body Milky Way-like galaxy. We assign a [Fe/H] value to each particle of the simulation according to an initial, cosmologically motivated, radial chemical distribution and let the disk dynamically evolve for 6 Gyr. This direct approach allows us to take into account only the effects of dynamical evolution and to gauge how and to what extent they affect the initial chemical conditions. The initial [Fe/H] distribution increases with R in the inner disk up to R ~ 10 kpc and decreases for larger R. We find that the initial chemical profile does not undergo major transformations after 6 Gyr of dynamical evolution. The final radial chemical gradients predicted by the model in the solar neighborhood are positive and of the same order of those recently observed in the Milky Way thick disk. We conclude that: 1) the spatial chemical imprint at the time of disk formation is not washed out by sec...

  3. Case Study of Signature Analysis on Engine Condition of Emergency Diesel Generators

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kwang Hee; Lee, Sang Guk; Lee, Byoung Oh [Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2012-05-15

    The effort has been done to effectively improve the maintenance method of emergency diesel generator (EDG) by changing from time based maintenance to condition based maintenance (CBM) in nuclear power plant. Technologies of engine signature analysis to evaluate the diesel generator condition have been applied to CBM for EDG in domestic and foreign nuclear power plants. Engine signature analysis includes both combustion analysis and vibration and ultrasonic analysis. Combustion analysis provides information on the combustion performance of the individual cylinders of the diesel engine. Vibration and ultrasonic analysis provides information on event timing and mechanical condition within the diesel engine. These signatures are collected non-intrusively during a normal loaded engine run. The primary impetus for the use of engine signature analysis has been as part of a program to replace the traditional time based open and inspection maintenance program imposed on plants by the original equipment manufacturers. Condition-based maintenance programs based largely on the use of engine signature analysis have increased the reliability and availability of diesel engine. The results of signature analysis on various cases in EDG of KHNP and overseas nuclear power plants are described in this paper

  4. THE CHEMICAL SIGNATURE OF A RELIC STAR CLUSTER IN THE SEXTANS DWARF SPHEROIDAL GALAXY—IMPLICATIONS FOR NEAR-FIELD COSMOLOGY

    International Nuclear Information System (INIS)

    We present tentative evidence for the existence of a dissolved star cluster at [Fe/H] = –2.7 in the Sextans dwarf spheroidal galaxy. We use the technique of chemical tagging to identify stars that are highly clustered in a multi-dimensional chemical abundance space (C-space). In a sample of six stars, three, possibly four, stars are identified as potential cluster stars. The initial stellar mass of the parent cluster is estimated from two independent observations to be M*,init=1.9+1.5-0.9(1.6+1.2-0.8)×105 Msun, assuming a Salpeter (Kroupa) initial mass function. If corroborated by follow-up spectroscopy, this star cluster is the most metal-poor system identified to date. Chemical signatures of remnant clusters in dwarf galaxies like Sextans provide us with a very powerful probe to the high-redshift universe. From available observational data, we argue that the average star cluster mass in the majority of the newly discovered ultra-faint dwarf galaxies was notably lower than it is in the Galaxy today and possibly lower than in the more luminous, classical dwarf spheroidal galaxies. Furthermore, the mean cumulative metallicity function of the dwarf spheroidals falls below that of the ultra-faints, which increases with increasing metallicity as predicted from our stochastic chemical evolution model. These two findings, together with a possible difference in the ([Mg/Fe]) ratio suggest that the ultra-faint dwarf galaxy population, or a significant fraction thereof, and the dwarf spheroidal population were formed in different environments and would thus be distinct in origin.

  5. THE CHEMICAL SIGNATURE OF A RELIC STAR CLUSTER IN THE SEXTANS DWARF SPHEROIDAL GALAXY-IMPLICATIONS FOR NEAR-FIELD COSMOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Torgny [Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden); Bland-Hawthorn, Joss [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Freeman, Ken C. [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston ACT 2611 (Australia); Silk, Joe, E-mail: torgny.karlsson@physics.uu.se [Physics Department, University of Oxford, Oxford OX1 3RH (United Kingdom)

    2012-11-10

    We present tentative evidence for the existence of a dissolved star cluster at [Fe/H] = -2.7 in the Sextans dwarf spheroidal galaxy. We use the technique of chemical tagging to identify stars that are highly clustered in a multi-dimensional chemical abundance space (C-space). In a sample of six stars, three, possibly four, stars are identified as potential cluster stars. The initial stellar mass of the parent cluster is estimated from two independent observations to be M{sub *,init}=1.9{sup +1.5}{sub -0.9}(1.6{sup +1.2}{sub -0.8}) Multiplication-Sign 10{sup 5} M{sub sun}, assuming a Salpeter (Kroupa) initial mass function. If corroborated by follow-up spectroscopy, this star cluster is the most metal-poor system identified to date. Chemical signatures of remnant clusters in dwarf galaxies like Sextans provide us with a very powerful probe to the high-redshift universe. From available observational data, we argue that the average star cluster mass in the majority of the newly discovered ultra-faint dwarf galaxies was notably lower than it is in the Galaxy today and possibly lower than in the more luminous, classical dwarf spheroidal galaxies. Furthermore, the mean cumulative metallicity function of the dwarf spheroidals falls below that of the ultra-faints, which increases with increasing metallicity as predicted from our stochastic chemical evolution model. These two findings, together with a possible difference in the ([Mg/Fe]) ratio suggest that the ultra-faint dwarf galaxy population, or a significant fraction thereof, and the dwarf spheroidal population were formed in different environments and would thus be distinct in origin.

  6. A Cross-Study Biomarker Signature of Human Bronchial Epithelial Cells Infected with Respiratory Syncytial Virus

    Science.gov (United States)

    Gardinassi, Luiz Gustavo

    2016-01-01

    Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infections in children, elderly, and immunocompromised individuals. Despite of advances in diagnosis and treatment, biomarkers of RSV infection are still unclear. To understand the host response and propose signatures of RSV infection, previous studies evaluated the transcriptional profile of the human bronchial epithelial cell line—BEAS-2B—infected with different strains of this virus. However, the evolution of statistical methods and functional analysis together with the large amount of expression data provide opportunities to uncover novel biomarkers of inflammation and infections. In view of those facts publicly available microarray datasets from RSV-infected BEAS-2B cells were analyzed with linear model-based statistics and the platform for functional analysis InnateDB. The results from those analyses argue for the reevaluation of previously reported transcription patterns and biological pathways in BEAS-2B cell lines infected with RSV. Importantly, this study revealed a biosignature constituted by genes such as ABCC4, ARMC8, BCLAF1, EZH1, FAM118A, FAM208B, FUS, HSPH1, KAZN, MAP3K2, N6AMT1, PRMT2, S100PBP, SERPINA1, TLK2, ZNF322, and ZNF337 which should be considered in the development of new molecular diagnosis tools.

  7. Seawater-like trace element signatures (REE + Y) of Eoarchaean chemical sedimentary rocks from southern West Greenland, and their corruption during high-grade metamorphism

    Science.gov (United States)

    Friend, C. R. L.; Nutman, A. P.; Bennett, V. C.; Norman, M. D.

    2008-02-01

    Modern chemical sediments display a distinctive rare earth element + yttrium (REE + Y) pattern involving depleted LREE, positive La/La*SN, Eu/Eu*SN, and YSN anomalies (SN = shale normalised) that is related to precipitation from circumneutral to high pH waters with solution complexation of the REEs dominated by carbonate ions. This is often interpreted as reflecting precipitation from surface waters (usually marine). The oldest broadly accepted chemical sediments are c. 3,700 Ma amphibolite facies banded iron-formation (BIF) units in the Isua supracrustal belt, Greenland. Isua BIFs, including the BIF international reference material IF-G are generally considered to be seawater precipitates, and display these REE + Y patterns (Bolhar et al. in Earth Planet Sci Lett 222:43 60, 2004). Greenland Eoarchaean BIF metamorphosed up to granulite facies from several localities in the vicinity of Akilia (island), display REE + Y patterns identical to Isua BIF, consistent with an origin by chemical sedimentation from seawater and a paucity of clastic input. Furthermore, the much-debated magnetite-bearing siliceous unit of “earliest life” rocks (sample G91/26) from Akilia has the same REE + Y pattern. This suggests that sample G91/26 is also a chemical sediment, contrary to previous assertions (Bolhar et al. in Earth Planet Sci Lett 222:43 60, 2004), and including suggestions that the Akilia unit containing G91/26 consists entirely of silica-penetrated, metasomatised, mafic rock (Fedo and Whitehouse 2002a). Integration of our trace element data with those of Bolhar et al. (Earth Planet Sci Lett 222:43 60, 2004) demonstrates that Eoarchaean siliceous rocks in Greenland, with ages from 3.6 to 3.85 Ga, have diverse trace element signatures. There are now geographically-dispersed, widespread examples with Isua BIF-like REE + Y signatures, that are interpreted as chemically unaltered, albeit metamorphosed, chemical sediments. Other samples retain remnants of LREE depletion but

  8. Studying chemical reactivity in a virtual environment.

    Science.gov (United States)

    Haag, Moritz P; Reiher, Markus

    2014-01-01

    Chemical reactivity of a set of reactants is determined by its potential (electronic) energy (hyper)surface. The high dimensionality of this surface renders it difficult to efficiently explore reactivity in a large reactive system. Exhaustive sampling techniques and search algorithms are not straightforward to employ as it is not clear which explored path will eventually produce the minimum energy path of a reaction passing through a transition structure. Here, the chemist's intuition would be of invaluable help, but it cannot be easily exploited because (1) no intuitive and direct tool for the scientist to manipulate molecular structures is currently available and because (2) quantum chemical calculations are inherently expensive in terms of computational effort. In this work, we elaborate on how the chemist can be reintroduced into the exploratory process within a virtual environment that provides immediate feedback and intuitive tools to manipulate a reactive system. We work out in detail how this immersion should take place. We provide an analysis of modern semi-empirical methods which already today are candidates for the interactive study of chemical reactivity. Implications of manual structure manipulations for their physical meaning and chemical relevance are carefully analysed in order to provide sound theoretical foundations for the interpretation of the interactive reactivity exploration. PMID:25340884

  9. Geophysical and Chemical Weathering Signatures Across the Deep Weathered-Unweathered Granite Boundary of the Calhoun Critical Zone Observatory

    Science.gov (United States)

    Richter, D., Jr.; Bacon, A. R.; Brantley, S. L.; Holbrook, W. S.

    2015-12-01

    To understand the relationship between geophysical measurements and chemical weathering at Earth's surface, we combine comprehensive chemical and physical analyses of a 70-m granite weathering profile in the Southern Piedmont in the southeastern United States. The research site is in the uplands of the Calhoun Critical Zone Observatory and is similar to many geomorphically stable, ancient, and highly-weathered Ultisol soils of the region. Surface and downhole geophysical analyses suggest significant physical changes to depths of about 40 m, where geophysical properties are consistent with competent and unweathered granite. At this depth, surface refraction velocities increase to >4.5 km/s; variations in downhole sonic velocities decrease by more than two-fold; and deviations in the downhole caliper log sharply decrease as well. Forty meters depth is also the depth of initiation of plagioclase feldspar weathering, as inferred from bulk geochemical measurement of the full 70-m deep core. Specifically, element-depth profiles, cast as mass transfer coefficient profiles using Ti and Zr as immobile elements, document inferred loss of plagioclase in the depth interval between 15 and 40-m depth. Plagioclase feldspar is the most abundant of the highly reactive minerals in the granite. Such a wide reaction front is characteristic of weathering granites. Some loss of K is observed at these depths but most K loss, as well as Mg loss, occurs at shallower depths. Nearby geophysical profiles and 3D stress models have been interpreted as showing that seismic velocities decrease at 40 m depth due to opening of fractures as rock is exhumed toward the surface. Given our interpretations of both the geochemical and geophysical data, we infer that the onset of chemical weathering of feldspar coincides with the opening of these fractures. The data highlight the ability of geochemistry and geophysics to complement each other and enrich our understanding of Earth's Critical Zone.

  10. Study of chemical and radiation induced carcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Chmura, A.

    1995-11-01

    The study of chemical and radiation induced carcinogenesis has up to now based many of its results on the detection of genetic aberrations using the fluorescent in situ hybridization (FISH) technique. FISH is time consuming and this tends to hinder its use for looking at large numbers of samples. We are currently developing new technological advances which will increase the speed, clarity and functionality of the FISH technique. These advances include multi-labeled probes, amplification techniques, and separation techniques.

  11. Theoretical studies of chemical reaction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Schatz, G.C. [Argonne National Laboratory, IL (United States)

    1993-12-01

    This collaborative program with the Theoretical Chemistry Group at Argonne involves theoretical studies of gas phase chemical reactions and related energy transfer and photodissociation processes. Many of the reactions studied are of direct relevance to combustion; others are selected they provide important examples of special dynamical processes, or are of relevance to experimental measurements. Both classical trajectory and quantum reactive scattering methods are used for these studies, and the types of information determined range from thermal rate constants to state to state differential cross sections.

  12. Kinetic studies of elementary chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Durant, J.L. Jr. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    This program concerning kinetic studies of elementary chemical reactions is presently focussed on understanding reactions of NH{sub x} species. To reach this goal, the author is pursuing experimental studies of reaction rate coefficients and product branching fractions as well as using electronic structure calculations to calculate transition state properties and reaction rate calculations to relate these properties to predicted kinetic behavior. The synergy existing between the experimental and theoretical studies allow one to gain a deeper insight into more complex elementary reactions.

  13. A spatiotemporal signature of cortical pain relief by tactile stimulation: An MEG study.

    Science.gov (United States)

    Hayamizu, Mariko; Hagiwara, Koichi; Hironaga, Naruhito; Ogata, Katsuya; Hoka, Sumio; Tobimatsu, Shozo

    2016-04-15

    Recently, the cortical mechanisms of tactile-induced analgesia have been investigated; however, spatiotemporal characteristics have not been fully elucidated. The insular-opercular region integrates multiple sensory inputs, and nociceptive modulation by other sensory inputs occurs in this area. In this study, we focused on the insular-opercular region to characterize the spatiotemporal signature of tactile-induced analgesia using magnetoencephalography in 11 healthy subjects. Aδ (intra-epidermal electrical stimulation) inputs were modified by Aβ (mechanical tactile stimulation) selective stimulation, either independently or concurrently, to the right forearm. The optimal inter-stimulus interval (ISI) for cortical level modulation was determined after comparing the 40-, 60-, and 80-ms ISI conditions, and the calculated cortical arrival time difference between Aδ and Aβ inputs. Subsequently, we adopted a 60-ms ISI for cortical modulation and a 0-ms ISI for spinal level modulation. Source localization using minimum norm estimates demonstrated that pain-related activity was located in the posterior insula, whereas tactile-related activity was estimated in the parietal operculum. We also found significant inhibition of pain-related activity in the posterior insula due to cortical modulation. In contrast, spinal modulation was observed both in the posterior insula and parietal operculum. Subjective pain, as evaluated by the visual analog scale, also showed significant reduction in both conditions. Therefore, our results demonstrated that the multisensory integration within the posterior insula plays a key role in tactile-induced analgesia. PMID:26854558

  14. CERTIFICATELESS SIGNATURE AND BLIND SIGNATURE

    Institute of Scientific and Technical Information of China (English)

    Zhang Lei; Zhang Futai

    2008-01-01

    Certificateless public key cryptography is a new paradigm introduced by AI-Riyami and Paterson. It eliminates the need of the certificates in traditional public key cryptosystems and the key escrow problem in IDentity-based Public Key Cryptography (ID-PKC). Due to the advantages of the certificateless public key cryptography,a new efficient certificateless pairing-based signature scheme is presented,which has some advantages over previous constructions in computational cost. Based on this new signature scheme,a certificateless blind signature scheme is proposed. The security of our schemes is proven based on the hardness of computational Diffie-Hellman problem.

  15. Outcome Prediction of Children with Neuroblastoma using a Multigene Expression Signature, a Retrospective SIOPEN/COG/GPOH Study

    Science.gov (United States)

    Vermeulen, Joëlle; De Preter, Katleen; Naranjo, Arlene; Vercruysse, Liesbeth; Roy, Nadine Van; Hellemans, Jan; Swerts, Katrien; Bravo, Sophie; Scaruffi, Paola; Tonini, Gian Paolo; Noguera, Rosa; Piqueras, Marta; Janoueix-Lerosey, Isabelle; Delattre, Olivier; Combaret, Valérie; Fischer, Matthias; Oberthuer, André; Ambros, Peter F.; Beiske, Klaus; Bénard, Jean; Marques, Barbara; Michon, Jean; Schleiermacher, Gudrun; Bernardi, Bruno De; Rubie, Hervé; Cañete, Adela; Castel, Victoria; Kohler, Janice; Pötschger, Ulrike; Ladenstein, Ruth; Hogarty, Michael D.; McGrady, Patrick; London, Wendy B.; Laureys, Geneviève; Speleman, Frank; Vandesompele, Jo

    2011-01-01

    BACKGROUND More accurate prognostic assessment of patients with neuroblastoma is required to improve the choice of risk-related therapy. The aim of this study is to develop and validate a gene expression signature for improved outcome prediction. METHODS Fifty-nine genes were carefully selected based on an innovative data-mining strategy and profiled in the largest neuroblastoma patient series (n=579) to date using RT-qPCR starting from only 20 ng of RNA. A multigene expression signature was built using 30 training samples, tested on 313 test samples and subsequently validated in a blind study on an independent set of 236 additional tumours. FINDINGS The signature accurately classifies patients with respect to overall and progression-free survival (p<0·0001). The signature has a performance, sensitivity, and specificity of 85·4% (95%CI: 77·7–93·2), 84·4% (95%CI: 66·5–94·1), and 86·5% (95%CI: 81·1–90·6), respectively to predict patient outcome. Multivariate analysis indicates that the signature is a significant independent predictor after controlling for currently used riskfactors. Patients with high molecular risk have a higher risk to die from disease and for relapse/progression than patients with low molecular risk (odds ratio of 19·32 (95%CI: 6·50–57·43) and 3·96 (95%CI: 1·97–7·97) for OS and PFS, respectively). Patients with increased risk for adverse outcome can also be identified within the current treatment groups demonstrating the potential of this signature for improved clinical management. These results were confirmed in the validation study in which the signature was also independently statistically significant in a model adjusted for MYCN status, age, INSS stage, ploidy, INPC grade of differentiation, and MKI. The high patient/gene ratio (579/59) underlies the observed statistical power and robustness. INTERPRETATION A 59-gene expression signature predicts outcome of neuroblastoma patients with high accuracy. The signature is

  16. The Gaia-ESO Survey: chemical signatures of rocky accretion in a young solar-type star

    CERN Document Server

    Spina, L; Randich, S; Sacco, G G; Jeffries, R; Magrini, L; Franciosini, E; Meyer, M R; Tautvaišienė, G; Gilmore, G; Alfaro, E J; Prieto, C Allende; Bensby, T; Bragaglia, A; Flaccomio, E; Koposov, S E; Lanzafame, A C; Costado, M T; Hourihane, A; Lardo, C; Lewis, J; Monaco, L; Morbidelli, L; Sousa, S G; Worley, C C; Zaggia, S

    2015-01-01

    It is well known that newly formed planetary systems undergo processes of orbital reconfiguration and planetary migration. As a result, planets or protoplanetary objects may accrete onto the central star, being fused and mixed into its external layers. If the accreted mass is sufficiently high and the star has a sufficiently thin convective envelope, such events may result in a modification of the chemical composition of the stellar photosphere in an observable way, enhancing it with elements that were abundant in the accreted mass. The recent Gaia-ESO Survey observations of the 10-20 Myr old Gamma Velorum cluster have enabled identifying a star that is significantly enriched in iron with respect to other cluster members. In this Letter we further investigate the abundance pattern of this star, showing that its abundance anomaly is not limited to iron, but is also present in the refractory elements, whose overabundances are correlated with the condensation temperature. This finding strongly supports the hypot...

  17. Marked influence of the nature of the chemical bond on CP-violating signature in molecular ions HBr+ and HI+

    International Nuclear Information System (INIS)

    Heavy polar molecules offer a great sensitivity to the electron electric dipole moment (EDM). To guide emerging searches for EDMs with molecular ions, we estimate the EDM-induced energy corrections for hydrogen halide ions HBr+ and HI+ in their respective ground X 2Π3/2 states. We find that the energy corrections due to EDM for the two ions differ by an unexpectedly large factor of 15. We demonstrate that a major part of this enhancement is due to a dissimilarity in the nature of the chemical bond for the two ions: the bond that is nearly of ionic character in HBr+ exhibits predominantly a covalent nature in HI+. We conclude that because of this enhancement the HI+ ion may be a potentially competitive candidate for the EDM search

  18. POLARIMETRIC SIGNATURES IDENTIFICATION FOR DIFFERENT FEATURES IN RADARSAT-2 POLSAR IMAGE: A CASE STUDY OF HALAYIB AREA, EGYPT

    Directory of Open Access Journals (Sweden)

    A. H. Nasr

    2016-06-01

    Full Text Available In fully polarized SAR (PolSAR data the returned signal from a target contains all polarizations. More information about this target may be inferred with respect to single-polarization. Distinct polarization separates targets due to its different backscattering responses. A Radarsat-2 PolSAR image acquired on December 2013 of part of Halayib area (Egypt was used in this study. Polarimetric signatures for various features (Wadi deposits, Tonalite, Chlorite schist, and Radar penetrated areas were derived and identified. Their Co-polarized and Cross-polarized signatures were generated, based on the calculation of the backscattered power at various ellipticity and orientation angles. Graphical 3D-representation of these features was provided and more details of their physical information are depicted according to their different polarization bases. The results illustrate that polarimetric signatures, obtained due to factors like surface roughness, dielectric constant and feature orientation, can be an effective representation for analyzing various features. The shape of the signature is significant and can also indicate the scattering mechanisms dominating the features response.

  19. Atmospheric aerosol compositions in China: spatial/temporal variability, chemical signature, regional haze distribution and comparisons with global aerosols

    Directory of Open Access Journals (Sweden)

    X. Y. Zhang

    2012-01-01

    Full Text Available From 2006 to 2007, the daily concentrations of major inorganic water-soluble constituents, mineral aerosol, organic carbon (OC and elemental carbon (EC in ambient PM10 samples were investigated from 16 urban, rural and remote sites in various regions of China, and were compared with global aerosol measurements. A large difference between urban and rural chemical species was found, normally with 1.5 to 2.5 factors higher in urban than in rural sites. Optically-scattering aerosols, such as sulfate (~16%, OC (~15%, nitrate (~7%, ammonium (~5% and mineral aerosol (~35% in most circumstance, are majorities of the total aerosols, indicating a dominant scattering feature of aerosols in China. Of the total OC, ~55%–60% can be attributed to the formation of the secondary organic carbon (SOC. The absorbing aerosol EC only accounts for ~3.5% of the total PM10. Seasonally, maximum concentrations of most aerosol species were found in winter while mineral aerosol peaks in spring. In addition to the regular seasonal maximum, secondary peaks were found for sulfate and ammonium in summer and for OC and EC in May and June. This can be considered as a typical seasonal pattern in various aerosol components in China. Aerosol acidity was normally neutral in most of urban areas, but becomes some acidic in rural areas. Based on the surface visibility observations from 681 meteorological stations in China between 1957 and 2005, four major haze areas are identified with similar visibility changes, namely, (1 Hua Bei Plain in N. China, and the Guanzhong Plain; (2 E. China with the main body in the Yangtze River Delta area; (3 S. China with most areas of Guangdong and the Pearl River Delta area; (4 The Si Chuan Basin in S.W. China. The degradation of visibility in these areas is linked with the emission changes and high PM concentrations. Such quantitative chemical characterization of aerosols is essential in assessing their role in atmospheric

  20. The Chemical Abundance Structure of the Inner Milky Way: A Signature of "Upside-Down" Disk Formation?

    CERN Document Server

    Freudenburg, Jenna K C; Hayden, Michael R; Holtzman, Jon A

    2016-01-01

    We present a model for the [alpha/Fe]-[Fe/H] distribution of stars in the inner Galaxy, R=3-5 kpc, measured as a function of vertical distance |z| from the midplane by Hayden et al. (2015, H15). Motivated by an "upside-down" scenario for thick disk formation, in which the thickness of the star-forming gas layer contracts as the stellar mass of the disk grows, we combine one-zone chemical evolution with a simple prescription in which the scale-height of the stellar distribution drops linearly from z_h=0.8 kpc to z_h=0.2 kpc over a timescale t_c, remaining constant thereafter. We assume a linear-exponential star-formation history, SFR ~ te^{-t/t_sf}. With a star-formation efficiency timescale of 2 Gyr, an outflow mass-loading factor of 1.5, t_sf=3 Gyr, and t_c=2.5 Gyr, the model reproduces the observed locus of inner disk stars in [alpha/Fe]-[Fe/H] and the metallicity distribution functions (MDFs) measured by H15 at |z|=0-0.5 kpc, 0.5-1 kpc, and 1-2 kpc. Substantial changes to model parameters lead to disagreem...

  1. The Gaia-ESO Survey: chemical signatures of rocky accretion in a young solar-type star

    Science.gov (United States)

    Spina, L.; Palla, F.; Randich, S.; Sacco, G.; Jeffries, R.; Magrini, L.; Franciosini, E.; Meyer, M. R.; Tautvaišienė, G.; Gilmore, G.; Alfaro, E. J.; Allende Prieto, C.; Bensby, T.; Bragaglia, A.; Flaccomio, E.; Koposov, S. E.; Lanzafame, A. C.; Costado, M. T.; Hourihane, A.; Lardo, C.; Lewis, J.; Monaco, L.; Morbidelli, L.; Sousa, S. G.; Worley, C. C.; Zaggia, S.

    2015-10-01

    It is well known that newly formed planetary systems undergo processes of orbital reconfiguration and planetary migration. As a result, planets or protoplanetary objects may accrete onto the central star, being fused and mixed into its external layers. If the accreted mass is sufficiently high and the star has a sufficiently thin convective envelope, such events may result in a modification of the chemical composition of the stellar photosphere in an observable way, enhancing it with elements that were abundant in the accreted mass. The recent Gaia-ESO Survey observations of the 10-20 Myr old Gamma Velorum cluster have enabled identifying a star that is significantly enriched in iron with respect to other cluster members. In this Letter we further investigate the abundance pattern of this star, showing that its abundance anomaly is not limited to iron, but is also present in the refractory elements, whose overabundances are correlated with the condensation temperature. This finding strongly supports the hypothesis of a recent accretion of rocky material. Based on observations made with the ESO/VLT, at Paranal Observatory, under program 188.B-3002 (The Gaia-ESO Public Spectroscopic Survey).

  2. Chemical and isotopic signature of groundwater after sea water encroachment in coastal aquifers of the Cornia river basin (Tuscany, Italy)

    International Nuclear Information System (INIS)

    Groundwaters in several regions within the Mediterranean basin exhibit a boron concentration which often exceeds the potability limit of 1 mg/L. The origin, fate and geochemical processes of boron in groundwater is now being investigated in Israel, Greece, Cyprus and Italy within the framework of the coordinated research project BOREMED, financially supported by the European Union. We report here the current status of the BOREMED investigations on groundwater of the Cornia Valley in Western Tuscany, Italy. Although high boron (up to 4 mg/L) is observed in inland groundwater as well, the emphasis of this presentation is on aspects related to the boron content of coastal aquifers of the Cornia Valley, which may attain 8 mg/L. This high boron concentration, although often well above that of seawater (5 mg/L), appears to be connected with sea water encroachment due to groundwater overexploitation. A geochemical explanation is proposed here, on the basis of the behaviour and contents of various chemical and isotopic tracers

  3. Identification of chemical signatures of gunshot residues in different fabrics; Identificacao de assinaturas quimicas em residuos de disparos de arma de fogo em diferentes alvos

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Joao Carlos Dias de

    2010-07-01

    The modern forensic science goes hand in hand with scientific research. The forensic scientists are faced every day with many cases requiring the analysis of residues from firing gun (gunshot residues). This works describes the development of a methodology to determine chemical signatures of shots from a firearm, by measuring the concentrations of Pb, Ba e Sb in the residues from these shots deposited near the entrance hole of bullets, based on the technique with high resolution inductively coupled plasma mass spectrometry (HRICP-MS). Shots were performed on five types of target-fabrics and collected testimonies from regions close to the entrance hole of projectiles. The results showed that the method enabled us to identify and distinguish the residues of the .38 caliber revolver and pistols .40 and 9mm caliber. The use of ternary graphs as a tool for data analysis helped to identify specific patterns of distribution of blank samples and gunshot residues deposited after firing revolvers and pistols. The methodology enabled the assignment of the origin of the shot through the confirmation of the residues collected also from the hands of shooters. As a result the methodology in police procedures and aims to add a valuable contribution to forensic investigations. (author)

  4. Brazilian oil spills chemical characterization : case studies

    International Nuclear Information System (INIS)

    The Petrobras Research Centre has been active in responding to some significant oil spills in Brazil in the past decade. The centre has characterized spilled oil, monitored the affected ecosystems and determined the fate of oil in the environment. This paper described the use of some advanced chemical analytical techniques used in Brazilian oil spill studies to determine fractions and individual petroleum hydrocarbons in water, groundwater, sediment, sand, fish and the spilled oil itself. Some of the most recent oil spill cases were discussed in terms of chemical characterization of the spilled oil and the environmental samples from different matrices of the affected ecosystems for determining the fate of the oil in the environment and to assess environmental damage. In particular, methods such as gas chromatography/flame ionization detector, P and T/GC/PID and gas chromatography/mass spectrometry have been used to examine crude and fuel oil spills in Guanabara Bay, Barigui and Iguassu Rivers, and the Sao Sebastiao Channel. The chemical analytical methods are used to determine total petroleum hydrocarbons, n-alkanes, isoprenoids, unresolved complex mixtures, volatile monoaromatic compounds such as BTEX (benzene, toluene, ethylbenzene and xylenes), as well as parent and alkylated homologues polycyclic aromatic hydrocarbons (PAH) and terpanes and steranes. Acute ecotoxicity data for water and sediment samples was also included. It was determined that with certain limitations, PAH ratios can help determine the origin of hydrocarbons as being either petrogenic or pyrolytic. However, alkylated PAH homologues and parent compounds such as dibenzothiophene and perylene give more precise interpretation of the data. 30 refs., 9 tabs., 11 figs

  5. Feasibility study on conducting overflight measurements of shaped sonic boom signatures using the Firebee BQM-34E RPV

    Science.gov (United States)

    Maglieri, Domenic J.; Sothcott, Victor E.; Keefer, Thomas N., Jr.

    1993-02-01

    A study was performed to determine the feasibility of establishing if a 'shaped' sonic boom signature, experimentally shown in wind tunnel models out to about 10 body lengths, will persist out to representative flight conditions of 200 to 300 body lengths. The study focuses on the use of a relatively large supersonic remotely-piloted and recoverable vehicle. Other simulation methods that may accomplish the objective are also addressed and include the use of nonrecoverable target drones, missiles, full-scale drones, very large wind tunnels, ballistic facilities, whirling-arm techniques, rocket sled tracks, and airplane nose probes. In addition, this report will also present a background on the origin of the feasibility study including a brief review of the equivalent body concept, a listing of the basic sonic boom signature characteristics and requirements, identification of candidate vehicles in terms of desirable features/availability, and vehicle characteristics including geometries, area distributions, and resulting sonic boom signatures. A program is developed that includes wind tunnel sonic boom and force models and tests for both a basic and modified vehicles and full-scale flight tests.

  6. A statistical study of the relative difficulty of freehand simulation of form, proportion, and line quality in Arabic signatures.

    Science.gov (United States)

    Al-Musa Alkahtani, Abdulaziz; Platt, Andrew W G

    2010-06-01

    This article compares the skill with which a large sample of Arabic writers was able to simulate different handwriting elements in two Arabic signatures. The data agree with the consensus of experts about Roman script: Form is significantly better simulated than Proportion, and Proportion is significantly better simulated than Line Quality. The fact that patterns long observed in Roman script simulation can be statistically demonstrated to exist in the simulation of Arabic signatures suggests that these may be widespread, if not universal, patterns of simulation among writing systems. This is also supported by similar results from a study of abstract characters (Leung et al. 1993), which suggests that these tendencies may even transcend linguistic writing systems. Among the Proportional elements are slant, alignment, spacing, and size. PMID:20470739

  7. Radiation signatures

    International Nuclear Information System (INIS)

    A new concept for modelling radiation risk is proposed. This concept is based on the proposal that the spectrum of molecular lesions, which we dub ''the radiation signature'', can be used to identify the quality of the causal radiation. If the proposal concerning radiation signatures can be established then, in principle, both prospective and retrospective risk determination can be assessed on an individual basis. A major goal of biophysical modelling is to relate physical events such as ionization, excitation, etc. to the production of radiation carcinogenesis. A description of the physical events is provided by track structure. The track structure is determined by radiation quality, and it can be considered to be the ''physical signature'' of the radiation. Unfortunately, the uniqueness characteristics of this signature are dissipated in biological systems in ∼10-9s. Nonetheless, it is our contention that this physical disturbance of the biological system eventuates later, at ∼100s, in molecular lesion spectra which also characterize the causal radiation. (author)

  8. Surface chemical studies of chemical vapour deposited diamond thin films

    International Nuclear Information System (INIS)

    Polycrystalime diamond grown by low pressure chemical vapour deposition (CVD) techniques has emerged in recent years as a new material with applications in such areas as optics, electronics, radiation detectors, chemical sensors and electrochemistry. A main aim of this thesis has been to advance current knowledge of the surface chemical properties of CVD diamond to underpin the development of our understanding of the properties and potential applications of this material. Cl2 is found to adsorb dissociatively on the clean, hydrogen-free diamond surface up to sub-monolayer coverage with a sticking probability of ∼1.2x10-3. Adsorption is a non-activated process, and the sticking probability and extent of coverage decreased with increasing temperature. This was shown to contrast with the behaviour found for the interaction of chlorine with the hydrogenated diamond surface where increased sticking probabilities and saturation surface coverages were observed, and where the reactivity also increased with temperature. Thermal desorption of atomic Cl occurred over a broad temperature range m both chemisorption systems, indicating the presence of more than one binding state. Atomic hydrogen was successful in efficiently etching the bound Cl from the surface. XeF2 was found to adsorb dissociatively onto the clean diamond surface to give up to monolayer coverages of F, which formed two distinct binding states. The first state, populated at low coverage, was predominantly covalent in character, while the second state, occurring at high surface coverages, had more ionic bonding character. Pre-hydrogenation of the diamond surface increased the reactive sticking probability observed, but decreased the extent of coverage by blocking reactive sites. The semi-ionic F was readily etched by atomic hydrogen, and underwent thermal desorption at temperatures as low as 300 deg C. The covalent form was more stable, being seemingly resistant to etching and persistent to high temperatures

  9. Application of a case–control study design to investigate genotypic signatures of HIV-1 transmission

    OpenAIRE

    Mota Talia M; Murray John M; Center Rob J; Purcell Damian F J; McCaw James M

    2012-01-01

    Abstract Background The characterization of HIV-1 transmission strains may inform the design of an effective vaccine. Shorter variable loops with fewer predicted glycosites have been suggested as signatures enriched in envelope sequences derived during acute HIV-1 infection. Specifically, a transmission-linked lack of glycosites within the V1 and V2 loops of gp120 provides greater access to an α4β7 binding motif, which promotes the establishment of infection. Also, a histidine at position 12 ...

  10. Chemical warfare, past and future. Study project

    Energy Technology Data Exchange (ETDEWEB)

    Tzihor, A.

    1992-05-15

    World War I was arena for the first use of chemical warfare. The enormous tactical success brought about by this first time use of chemical weapons caused the continued development of more sophisticated tactics and weapons in this category of unconventional warfare. This phenomenon has carried through to today. However, at present, because of technological developments, the global economic situation, and political factors, coupled with the inability of the western world to control the proliferation of chemical weapons, a situation weapon of mass destruction. Recent use by Iraq against Kurdish civilian indicates that chemical warfare is no longer limited to the battlefield. The western nations have a need to understand the risk. This paper conducts an analysis of past lessons and the factors which will affect the use of chemical warfare in the future. From this analysis, the paper reaches conclusions concerning the significant threat chemical weapons pose for the entire world in the not too distant future.

  11. Groundwater chemistry and isotope signatures of potential CCS sites in Korea - A baseline study for leakage detection

    Science.gov (United States)

    Choi, H.; Jeong, T.; Woo, N. C.

    2013-12-01

    This research aimed at drawing a baseline of groundwater chemistry and its stable isotope signatures of hydrogen, oxygen and carbon from the deep groundwater above the CO2 sequestration layer, in which physico-chemical conditions are conceived as temperature over 40 degree Celcius and high total dissolved solids. Samples were collected from hot springs (at surface and from seep wells) and high-carbonate springs. Based on water compositions, three groups were identified as saline, alkali-carbonate and soda spring types. Saline type hot springs at the west coastline area contain -14.5‰ δ13C of CO2. Before and after rainfall events, δ13C value of samples shows no change. Hot springs at Suanbo region, located at the center are of the Korean Peninsular, were collected from deep wells of 750 m in depth, and they show the alkali-carbonate type water having δ13C values (-11.3~-10.9‰) and ECs (364~431μS/cm). Both saline and alkali-carbonate type waters show no significant change in composition, indicating that recharge by precipitation has no effect on these groundwater. All the high-carbonate springs were collected at ground surface, and enriched with Ca, Mg and HCO3., probably caused by the dissolution of CO2, and high EC values of 1,016 μS/cm. Soda springs located in Chungcheongbuk-do region have -6.8~-6.7‰ δ13C of CO2, indicating that the source of CO2 could be the upper mantle affected by the carbonate minerals in the Quaternary sedimentary bedrock. On the contrary, carbonate waters in the Gangwon-do region have -3.9~-3.7‰ δ13C of CO2, clearly indicating the source of CO2 being the upper mantle (Gerlach and Taylor, 1990). More detailed chemical and isotopic signatures of the sampled waters will be discussed in presentation.

  12. Plant- versus microbial signature in densimetric fractions of mediterranean forest soils: a study by thermochemolysis gas chromatography mass spectrometry

    Science.gov (United States)

    Rovira, Pere; Grasset, Laurent

    2015-04-01

    Plant- versus microbial signature in densimetric fractions of mediterranean forest soils: a study by thermochemolysis gas chromatography mass spectrometry The ageing of a given organic substrate decomposing in soil is strongly dependant of its microbial utilization and transformation (reworking) by the soil microflora. How far a given substrate or soil fraction has gone in this evolution is usually measured by means of molecular signatures, ratios between organic compounds which enlighten us about the origin and/or the degree of microbial reworking of a specific group of compounds: lipids, proteins, lignin, carbohydrates, etc. Owing to the biochemical heterogeneity of decomposing substrates it is unlikely that the degree of microbial reworking can be approached with a single signature. Applying a couple of them is much better, but obtaining a wide collection of molecular signatures can be time consuming. Here, instead of applying specific methods to obtain a collection of specific signatures, we apply TMAH-thermochemolysis to obtain a panoramic view of the biochemical composition of a series of densimetric fractions of soils. From the compounds identified after TMAH-thermochemolysis, a collection of indicators was obtained: (a) ratio between short and long-chained linear alkanoic acids; (b) ratio between branched and long-chained linear alkanoic acids; (c) ratio between C16 and total alpha-omega-alkanedioic acids; (d) ratio microbial to plant-derived 1-methoxyalkanes; (e) ratio syringyl to total lignin-derived phenolic compounds; (f) vanillic acid to vanillin ratio; (g) fucose/glucose ratio; and (h) xylose/glucose ratio. From these indicators a single numerical value is distilled, allowing to order a couple of densimetric fractions of soil organic matter according to its degree of microbial reworking. This approach was applied to the comparison of a couple of densimetric fractions of soil organic matter of three organic H horizons from mediterranean forest soils

  13. Quantum chemical studies of estrogenic compounds

    Science.gov (United States)

    Quantum chemical methods are potent tools to provide information on the chemical structure and electronic properties of organic molecules. Modern computational chemistry methods have provided a great deal of insight into the binding of estrogenic compounds to estrogenic receptors (ER), an important ...

  14. Constraining chemical geothermometry with reactive transport models: An example study of the Dixie Valley geothermal area

    Science.gov (United States)

    Wanner, C.; Peiffer, L.; Spycher, N.; Sonnenthal, E. L.; Iovenitti, J. L.; Kennedy, B. M.

    2012-12-01

    In this study, 1D and 2D reactive transport simulations of the Dixie Valley geothermal area (Nevada, USA) were performed using Toughreact [1] to evaluate the fluid flow pathways and rates of equilibration of hydrothermal fluids. Modeling studies were combined with new multicomponent geothermometry, which is being used to estimate the temperature of geothermal reservoirs based on chemical analysis of geothermal springs. The concept is based on the assumption of chemical equilibrium between the thermal fluid and minerals of the reservoir rock [2]. If re-equilibration occurs between the reservoir at depth and the surface, then the 'deep' chemical signature of the fluid is lost and the obtained reservoir temperature is underestimated. The simulations were run for a vertical cross-section that has been structurally and geologically characterized. Model calibration was performed using available site information such as chemical analysis of geothermal springs, isotherms inferred from geothermal wells and results of a previous flow simulation study [3]. Model runs included the simulation of typical near-surface processes such as dilution, mixing and salt leaching occurring at the Dixie Valley geothermal area. Each reactive transport model produced 'synthetic' waters that were processed using the multicomponent chemical geothermometer code GeoT [4]. This code computes the saturation indices of reservoir minerals as a function of the temperature. Reservoir temperature is inferred when mineral saturation indices all cluster around zero. GeoT results were also compared with classical solute geothermometers (silica, Na-K-(Ca), K-Mg) [5]. Simulation results reveal that a minimum vertical fluid velocity on the order of a meter per day is needed to preserve the geochemical signature of a geothermal reservoir and to predict its temperature. The simulations also show that deep geochemical signatures are well preserved if fracture surfaces are partially coated by secondary minerals

  15. System chemical biology studies of endocrine disruptors

    DEFF Research Database (Denmark)

    Taboureau, Olivier; Oprea, Tudor I.

    Endocrine disrupting chemicals (EDCs) alter hormonal balance and other physiological systems through inappropriate developmental or adult exposure, perturbing the reproductive function of further generations. While disruption of key receptors (e.g., estrogen, androgen, and thyroid) at the ligand...

  16. Theoretical study of chemical reactions in solution

    International Nuclear Information System (INIS)

    Quantum chemical calculations in solution are becoming more and more important in chemistry. Reference interaction site model self-consistent field (RISM-SCF) is one of the powerful approaches to perform quantum chemical calculations in solution. In this work, we developed a new generation of RISM-SCF, where a robust fitting method was newly introduced. We applied the new method to tautomerization reaction of cytosine in aqueous phase. Our calculation reproduced experimentally obtained relative stabilities and relative free energies correctly

  17. Chemical feedbacks in climate sensitivity studies

    Science.gov (United States)

    Dietmüller, Simone; Ponater, Michael; Sausen, Robert

    2013-04-01

    Interactively coupled climate chemistry models extend the number of feedback mechanisms in climate change simulations by allowing a variation of several radiatively actice chemical tracers that are prescribed in conventional climate models. Different perturbation experiments including chemical feedbacks were performed using the chemistry-climate model system EMAC coupled to the mixed layer ocean model MLO. The influence of the chemical feedbacks O3, CH4 and N2O on climate response and climate sensitivity is quantified for a series of CO2-perturbation simulations: Equilibrium climate sensitivity is dampened, if chemical feedbacks are included. In case of a CO2 doubling simulation chemical feedbacks decrease climate sensitivity by -3.6% and in case of a 4*CO2 simulation by -8.1%. Analysis of the chemical feedbacks reveals, that the negative feedback of ozone, mainly the feedback of stratospheric ozone, is responsible for this dampening. The radiative feedbacks of CH4 and N2O are negligible, mainly because the model system does not allow interactive emission feedbacks at the Earth's surface for these gases. The feedback of physical parameters is significantly modified by the presence of chemical feedbacks. In case of the CO2-perturbation experiments the negative stratospheric ozone feedback is accompanied by a negative stratospheric H2O feedback change of the same order of magnitude. So the dampening effect of the direct O3 radiative feedback is enhanced. A non-linearity in the damping is found with increasing CO2 concentrations. Reasons are the nonlinear feedbacks of ozone, temperature, and stratospheric water vapor. Additional 6*CO2 simulations with and without chemical feedbacks included show, that the presence of chemic feedbacks helps to prevent a runaway greenhouse effect, as the O3 distribution can react to the upward shift of the tropopause. Also experiments driven by anthropogenic NOx- and CO-emissions were performed, where chemically active trace gases act

  18. The signature package on Witt spaces, II. Higher signatures

    CERN Document Server

    Albin, Pierre; Mazzeo, Rafe; Piazza, Paolo

    2009-01-01

    This is a sequel to the paper "The signature package on Witt spaces, I. Index classes" by the same authors. In the first part we investigated, via a parametrix construction, the regularity properties of the signature operator on a stratified Witt pseudomanifold, proving, in particular, that one can define a K-homology signature class. We also established the existence of an analytic index class for the signature operator twisted by a C^*_r\\Gamma Mischenko bundle and proved that the K-homology signature class is mapped to the signature index class by the assembly map. In this paper we continue our study, showing that the signature index class is invariant under rational Witt bordisms and stratified homotopies. We are also able to identify this analytic class with the topological analogue of the Mischenko symmetric signature recently defined by Banagl. Finally, we define Witt-Novikov higher signatures and show that our analytic results imply a purely topological theorem, namely that the Witt-Novikov higher sign...

  19. Sex hormones and gene expression signatures in peripheral blood from postmenopausal women - the NOWAC postgenome study

    Directory of Open Access Journals (Sweden)

    Rylander Charlotta

    2011-03-01

    Full Text Available Abstract Background Postmenopausal hormone therapy (HT influences endogenous hormone concentrations and increases the risk of breast cancer. Gene expression profiling may reveal the mechanisms behind this relationship. Our objective was to explore potential associations between sex hormones and gene expression in whole blood from a population-based, random sample of postmenopausal women Methods Gene expression, as measured by the Applied Biosystems microarray platform, was compared between hormone therapy (HT users and non-users and between high and low hormone plasma concentrations using both gene-wise analysis and gene set analysis. Gene sets found to be associated with HT use were further analysed for enrichment in functional clusters and network predictions. The gene expression matrix included 285 samples and 16185 probes and was adjusted for significant technical variables. Results Gene-wise analysis revealed several genes significantly associated with different types of HT use. The functional cluster analyses provided limited information on these genes. Gene set analysis revealed 22 gene sets that were enriched between high and low estradiol concentration (HT-users excluded. Among these were seven oestrogen related gene sets, including our gene list associated with systemic estradiol use, which thereby represents a novel oestrogen signature. Seven gene sets were related to immune response. Among the 15 gene sets enriched for progesterone, 11 overlapped with estradiol. No significant gene expression patterns were found for testosterone, follicle stimulating hormone (FSH or sex hormone binding globulin (SHBG. Conclusions Distinct gene expression patterns associated with sex hormones are detectable in a random group of postmenopausal women, as demonstrated by the finding of a novel oestrogen signature.

  20. A Chemical Genetic Approach To The Study Of Cellular Transport

    NARCIS (Netherlands)

    Nieland, T.J.F.

    2005-01-01

    The focus of this thesis is the use of chemical genetics to study two different aspects of membrane biology, (a) the mechanisms underlying cellular lipid transport and (b) the intersection between endocytic and exocytic traffic. The broad goals of chemical genetics are to find novel chemical tool

  1. Study of Endocrine Disrupting Chemicals in Environment

    Directory of Open Access Journals (Sweden)

    Zoltán Juvancz

    2008-06-01

    Full Text Available Endocrine disrupting chemicals (EDC cause more and more seriousenvironmental pollutions. The EDCs show only ng-μg/l concentration level in theenvironment, therefore their determinations require multistep sample preparationprocesses and highly sophisticated instrumentation. This paper discuss the EDC effects,and show examples for determination of such compounds.

  2. Experimental study of chemical concentration variation of ASP flooding

    Institute of Scientific and Technical Information of China (English)

    WANG JiaLu; YUAN ShiYi; SHI FaShun; JIA Xu

    2009-01-01

    A physical modeling system of long slim tube was established. Several pressure measuring and sampling points were laid out at different positions along the tube. Through real-time measurements of pressures and chemical concentrations at different points, the mass transfer and chemical concentration of ASP flooding in porous media are studied. The concentration of chemicals declines gradually during the fluid flow from the inlet to the outlet of the model. The concentration increases in the front edge of the slug faster than the concentration decreases in the rear edge of the slug. The concentration variation of the chemicals is an asymmetrical and offset process. The order of motion velocities of the chemicals from fast to slow is polymer, alkali and surfactant. The motion lag and comprehensive diffusion are strong in the vicinity of the inlet, the motion velocities of the chemicals are high, the difference of flow velocities among the three chemicals is significant and the chromatographic separation of the chemicals is obvious. In the area near the outlet, the comprehensive diffusion and motion lag become weak, the concentrations of the chemicals decrease, the motion velocities of the chemicals are slow,the difference among the motion velocities of the chemicals becomes small, the chromatographic separation is not obvious, the adsorption and retention of chemicals gradually increase as the chemical slug moves further along the tube, the adsorption and retention of polymer is the most serious.

  3. Experimental study of chemical concentration variation of ASP flooding

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A physical modeling system of long slim tube was established. Several pressure measuring and sampling points were laid out at different positions along the tube. Through real-time measurements of pressures and chemical concentrations at different points, the mass transfer and chemical concentration of ASP flooding in porous media are studied. The concentration of chemicals declines gradually during the fluid flow from the inlet to the outlet of the model. The concentration increases in the front edge of the slug faster than the concentration decreases in the rear edge of the slug. The concentration variation of the chemicals is an asymmetrical and offset process. The order of motion velocities of the chemicals from fast to slow is polymer, alkali and surfactant. The motion lag and comprehensive diffusion are strong in the vicinity of the inlet, the motion velocities of the chemicals are high, the difference of flow velocities among the three chemicals is significant and the chromatographic separation of the chemicals is obvious. In the area near the outlet, the comprehensive diffusion and motion lag become weak, the concentrations of the chemicals decrease, the motion velocities of the chemicals are slow, the difference among the motion velocities of the chemicals becomes small, the chromatographic separation is not obvious, the adsorption and retention of chemicals gradually increase as the chemical slug moves further along the tube, the adsorption and retention of polymer is the most serious.

  4. Chemical approaches to studying stem cell biology

    Institute of Scientific and Technical Information of China (English)

    Wenlin Li; Kai Jiang; Wanguo Wei; Yan Shi; Sheng Ding

    2013-01-01

    Stem cells,including both pluripotent stem cells and multipotent somatic stem cells,hold great potential for interrogating the mechanisms of tissue development,homeostasis and pathology,and for treating numerous devastating diseases.Establishment of in vitro platforms to faithfully maintain and precisely manipulate stem cell fates is essential to understand the basic mechanisms of stem cell biology,and to translate stem cells into regenerative medicine.Chemical approaches have recently provided a number of small molecules that can be used to control cell selfrenewal,lineage differentiation,reprogramming and regeneration.These chemical modulators have been proven to be versatile tools for probing stem cell biology and manipulating cell fates toward desired outcomes.Ultimately,this strategy is promising to be a new frontier for drug development aimed at endogenous stem cell modulation.

  5. Engineering studies on chemical uranium enrichment

    International Nuclear Information System (INIS)

    In multi-stage separation processes such as the Chemical Enrichment Process, back mixing phenomena are a matter of vital importance for understanding separation efficiency. Back mixing is composed of two parts, microscopic and macroscopic. The microscopic back mixing is known through molecular theory. The macroscopic back mixing effects are quantitatively determined using flow patterns obtained through computational calculations of the fluid dynamics, as well as experimental data. Judging from physical theory and experimental results, the sum of microscopic and the macroscopic back mixing terms is approximately 300μm in the Chemical Enrichment Process. This technology will also contribute to nuclear science in that it can be applied not only to the isotope separation of other elements and to other multi-stage separation processes, but also to the reprocessing of spent fuel. (author)

  6. Physico-chemical study on guar gum

    International Nuclear Information System (INIS)

    Guar plant is an annual summer plant and it can resist diseases, pests and drought. Guar gum is used in a lot of industries. The present study deals with some physical properties of two commercial grade samples of guar gum cyamopsis tetragonoloba which where produced in 1996 and 1997 seasons (S1 and S2 respectively). Our analytical data are compared with those of previous workers in this area and international quality. Guar gum (S2) is separated into water-insoluble components. Three fractions were obtained from the water-soluble components by fractional participation using acetone. Guar gum powder is yellowish white; the water-insoluble component is brownish white. Comparison study between gum samples (S1 and S2) and water-insoluble fraction (1) and water-soluble fractions are close to each other in their physico-properties. chemical All samples and fractions contain galactomannan polysaccharide as explained by infra-red spectra.Moisture contents for the gum samples were 5.2% and 7.8% and that for the water-insoluble fraction 4.7% while that for fraction samples were 5.2%-7.5% ash contents for the gum samples was 0.81% and 1.14% and for the water-insoluble component 0.88% while the contents in the fractions between 0.5%-0.66%. Nitrogen content determination showed that the gum samples had value of 0.678% and 0.732% and water -insoluble fraction had a value of 0.118%. The values decreased in the water-soluble fractions giving 0.049%, 0.053 and 0.056%. Water-soluble component and its fractions record the following results: pH measurements showed that the water-soluble component had pH 6.70 and 6.84 while its fractions had pH 5.90 and 7.00. Viscosity measurements showed that water-soluble fractions had intrinsic viscosity of 6.4 and 6.8 dL. g-1. The fractions derived from water-soluble fraction had intrinsic viscosity of 6.6, 7 and 7.5 dl. g-1. Using Mark-Howink equation, calculated average molecular weights for the water-soluble components were 7.01x105, and 7.62x

  7. Studies on Chemical Constituents From Artabotrys Hainanensis

    Institute of Scientific and Technical Information of China (English)

    CHEN Guangying; SONG Xiao-Ping; HAN Chang-ri

    2004-01-01

    Artabotrys Hainanensis R.E. Fries are plants of the Annonaccac family artabotrys genus,which includes an estimated 100 types of plants distributed mainly in the tropical zone and the subtropics areas. Four types of the plants are discovered in our country, two of which, A.Hongkongensis Hance and A. hexapetalus (Linn. F.) Bhandari, in Guangdong Province, and the other two, A. Pilosus and A. Hainanensis R.E. Fries, in Hainan Province. The latter are widely distributed in Hainan Island with very rich reserves. They have long been used among the ordinary people as medicinal plants with antipyretic, antidotal, antiphlogistic and analgesic effects and are often used for malaria. Scholars from home and abroad have paid much attention to the plants of the Annonaccac family for their containing anti-tumor activities, and after early or late research of the chemical constituents of the root, stem (derm), leaf and fruit of many types of plants of Artabotrys genus, more than 40 compounds including alkaloid, flavone and terpenoid have been isolated and obtained. Artabotrys Hainanensis R.E. Fries are Hainan endemic plants and there has been no report on the research of their chemical constituents and biological activities so far. In order to find new constituents of pharmacologic activity, we have researched the chemical constituents of the leaf and stem.The crude drugs were collected from Hainan Jianfeng Mountain and were identified as Artabotrys Hainanensis R.E. Fries of the Annonaccac family artabotrys genus. Its sample specimen is now kept in Chemistry Department of Hainan Normal University.After isolation and identification of constituent, six compounds were isolated from the leaf of Artabotrys Hainanensis R.E. Fries and elucidated as β -sitosterol (Ⅰ), catechin (Ⅱ), mangiferin (Ⅲ),(Ⅳ), (Ⅴ), (Ⅵ). All the compounds were obtained from this plant for the first time. Compounds Ⅱ, Ⅲ,Ⅳ, Ⅴ and Ⅵ were obtained from the genus of Artabotrys for the first time.

  8. [Studies on chemical constituents of Tinospora hainanesis].

    Science.gov (United States)

    Guo, Y; Lin, L; Shen, J

    1998-05-01

    Tinospora hainanesis is a new species of Menispermaceae plant. It is used as folk remedy for joint pain and physical injury. Five compounds were isolated from the vine stalk of Tinospora hainanesis. By spectral analysis and chemical methods, the structures of the compounds were identified as makisterone A (I), 2,3-dimethoxy-9,10-dihydroxy-N-methyltetrahydroproto-berberine quaternary salt (II), palmatine (III), beta-amyrin (IV) and docosyl ferulate (V). II is a new quaternary alkaloid named as haitinosporine. I, IV and V were isolated for the first time from the plants of Tinospora genus. PMID:12017002

  9. System chemical biology studies of endocrine disruptors

    DEFF Research Database (Denmark)

    Taboureau, Olivier; Oprea, Tudor I.

    Endocrine disrupting chemicals (EDCs) alter hormonal balance and other physiological systems through inappropriate developmental or adult exposure, perturbing the reproductive function of further generations. While disruption of key receptors (e.g., estrogen, androgen, and thyroid) at the ligand...... binding domain (LBD) has been associated with EDCs, a significant number of EDCs do not appear to influence the LBDs of these receptors. Therefore, we evaluated the potential biological effects of EDCs in humans with the aim to rationalize the etiology of certain disorders associated with the reproductive...

  10. Chemical Equilibrium in Supramolecular Systems as Studied by NMR Spectrometry

    Science.gov (United States)

    Gonzalez-Gaitano, Gustavo; Tardajos, Gloria

    2004-01-01

    Undergraduate students are required to study the chemical balance in supramolecular assemblies constituting two or more interacting species, by using proton NMR spectrometry. A good knowledge of physical chemistry, fundamentals of chemical balance, and NMR are pre-requisites for conducting this study.

  11. THE STUDY OF CHEMICAL COMPOSITION FOR ANIMAL FATS DURING STORAGE

    OpenAIRE

    Flavia Pop; Cornel Laslo

    2009-01-01

    In this article the chemical composition for 3 types of animal fats (pork fat, beef tallow and buffalo tallow), following the variation of saturated and unsaturated fatty acids proportion during freezing storage was studied. Determination of chemical composition of animal fats is important in establishing organoleptic and physico-chemical parameters, the variation of them in time, nature and proportion of fatty acids conferring specific characteristics to them. For pork fat was determined the...

  12. Physico-chemical studies of industrial pollutants

    International Nuclear Information System (INIS)

    Pollution problem industrial estates in more acute in some areas and district Haripur is one of those places. Industrial wastewater generated form various industries is drained into the natural streams / nallahs, which ultimately join river Indus through river Haro. Effluent of different industries were collected periodically and analysed for pH, conductivity, hardness, alkalinity/ acidity, chemical oxygen demand (COD), suspended and dissolved solids, ammonia and chlorine. cations like calcium, magnesium and iron, anions like phosphate, chlorides, sulphates and sulphides were also checked, using standard analytical techniques. Trace metals like arsenic cadmium, chromium cobalt copper lead manganese, nickel, tin and zinc were also detected by atomic absorption spectroscopy in the effluent samples. These results were evaluated and compared with the National Environmental Quality Standards (NEQS). Effluent of the fertilizer industries in Haripur, (both phosphatic and nitrogenous) are producing pollution and causing damage to the flora and fauna in the area. Effluent of the phosphatic fertilizer is acidic, having pH 1.5-3.0 due to acid, while effluent of nitrogenous fertilizer is alkaline having pH 9.0 -10.5 due to ammonia. Suggestion for useful remedial measures and the effective control of the pollutants are discussed. (author)

  13. Contribution to chemical-mineralogical study of carbonatites

    International Nuclear Information System (INIS)

    A preliminary chemical-mineralogical study of carbonatites from Jacupiranga (SP,Brazil) and Alto Pinheiros (SC,Brazil) enabled not only to ratify hypotheses previously described by Brazilian researchers but also made clear certain aspects related to the geochemistry of carbonatites concerning their occurrence, the probable genesis of these species and their chemical and mineralogical characteristics.(Author)

  14. Recent achievements in chemical studies of heaviest elements

    Science.gov (United States)

    Gäggeler, H. W.

    2011-09-01

    Discovery of heavy elements up to atomic number 118 at FLNR in Dubna has paved the way to also extend chemical knowledge to heavier members of the periodic table. Recent studies on the chemical properties of Cn and element 114 are summarized that have been performed at FLNR in Dubna using the fusion reactions 48Ca + 242/244Pu.

  15. Recent achievements in chemical studies of heaviest elements

    International Nuclear Information System (INIS)

    Discovery of heavy elements up to atomic number 118 at FLNR in Dubna has paved the way to also extend chemical knowledge to heavier members of the periodic table. Recent studies on the chemical properties of Cn and element 114 are summarized that have been performed at FLNR in Dubna using the fusion reactions 48Ca + 242/244Pu.

  16. Unprecedented accurate abundances: signatures of other Earths?

    CERN Document Server

    Melendez, J; Gustafsson, B; Yong, D; Ramírez, I

    2009-01-01

    For more than 140 years the chemical composition of our Sun has been considered typical of solar-type stars. Our highly differential elemental abundance analysis of unprecedented accuracy (~0.01 dex) of the Sun relative to solar twins, shows that the Sun has a peculiar chemical composition with a ~20% depletion of refractory elements relative to the volatile elements in comparison with solar twins. The abundance differences correlate strongly with the condensation temperatures of the elements. A similar study of solar analogs from planet surveys shows that this peculiarity also holds in comparisons with solar analogs known to have close-in giant planets while the majority of solar analogs without detected giant planets show the solar abundance pattern. The peculiarities in the solar chemical composition can be explained as signatures of the formation of terrestrial planets like our own Earth.

  17. Android应用程序数字签名机制研究%Studying of the Signature Authentication Mechanism in Android

    Institute of Scientific and Technical Information of China (English)

    吴文焕

    2014-01-01

    Android系统要求所有应用程序必须具有数字签名,否则将无法安装使用。Android采用签名机制来对开发者身份进行鉴别,防止应用程序被替换或篡改。本文主要研究Android应用程序数字签名的算法、实现方式,并对其安全性进行分析。%Android system requires that all applications must have a digital signature, otherwise it will not install and use. Android uses a signature mechanism to authenticate the identity of the developer to prevent the application being replaced or tampered with. This paper studies the Android application digital signature algorithms, implementations and analyze its security.

  18. Chemical - Elwha River Dam Removal Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study examines the ecosystem response of the Elwha River to the removal of the Elwha River dams. We will measure the following attributes of ecosystem...

  19. Studies on Semantic Systems Chemical Biology

    Science.gov (United States)

    Chen, Bin

    2012-01-01

    Current "one disease, one target and one drug" drug development paradigm is under question as relatively few drugs have reached the market in the last two decades. Increasingly research focus is being placed on the study of drug action against biological systems as a whole rather than against a single component (called "Systems…

  20. Enhanced scope of a Phase 2 CMS detector for the study of exotic physics signatures at the HL-LHC

    CERN Document Server

    CMS Collaboration

    2016-01-01

    The high luminosity LHC (HL-LHC) run, which is due to start in 2025, is expected to collect an integrated luminosity of approximately $3000~\\mathrm{fb}^{-1}$ at $\\sqrt{s}=14~\\mathrm{TeV}$. The discovery and study of physics beyond the standard model will remain one of the major goals of the CMS collaboration during this period. Such physics can yield exotic signatures, whose observation places unusual demands on the performance and capabilities of the detector. For a few selected exotic physics models, we present studies of what can be achieved using CMS data during the HL-LHC run. We look at how this potential is influenced by the design of the upgraded CMS detector, as documented in the $\\mathrm{phase~2}$ technical proposal. This document provides supplementary material for a deeper level of understanding of these studies. In the case of a high mass resonance decaying to leptons, we explore the hypothesis that this is discovered prior to 2025, and examine what would be learned about the resonance's properti...

  1. Common methods for fecal sample storage in field studies yield consistent signatures of individual identity in microbiome sequencing data.

    Science.gov (United States)

    Blekhman, Ran; Tang, Karen; Archie, Elizabeth A; Barreiro, Luis B; Johnson, Zachary P; Wilson, Mark E; Kohn, Jordan; Yuan, Michael L; Gesquiere, Laurence; Grieneisen, Laura E; Tung, Jenny

    2016-01-01

    Field studies of wild vertebrates are frequently associated with extensive collections of banked fecal samples-unique resources for understanding ecological, behavioral, and phylogenetic effects on the gut microbiome. However, we do not understand whether sample storage methods confound the ability to investigate interindividual variation in gut microbiome profiles. Here, we extend previous work on storage methods for gut microbiome samples by comparing immediate freezing, the gold standard of preservation, to three methods commonly used in vertebrate field studies: lyophilization, storage in ethanol, and storage in RNAlater. We found that the signature of individual identity consistently outweighed storage effects: alpha diversity and beta diversity measures were significantly correlated across methods, and while samples often clustered by donor, they never clustered by storage method. Provided that all analyzed samples are stored the same way, banked fecal samples therefore appear highly suitable for investigating variation in gut microbiota. Our results open the door to a much-expanded perspective on variation in the gut microbiome across species and ecological contexts. PMID:27528013

  2. An individual and a sex odor signature in kittiwakes? Study of the semiochemical composition of preen secretion and preen down feathers

    Science.gov (United States)

    Leclaire, Sarah; Merkling, Thomas; Raynaud, C.; Giacinti, Géraldine; Bessiere, J.-M.; Hatch, Scott A.; Danchin, Etienne

    2011-01-01

    The importance of olfaction in birds' social behavior has long been denied. Avian chemical signaling has thus been relatively unexplored. The black-legged kittiwake provides a particularly appropriate model for investigating this topic. Kittiwakes preferentially mate with genetically dissimilar individuals, but the cues used to assess genetic characteristics remain unknown. As in other vertebrates, their body odors may carry individual and sexual signatures thus potentially reliably signaling individual genetic makeup. Here, we test whether body odors in preen gland secretion and preen down feathers in kittiwakes may provide a sex and an individual signature. Using gas chromatography and mass spectrometry, we found that male and female odors differ quantitatively, suggesting that scent may be one of the multiple cues used by birds to discriminate between sexes. We further detected an individual signature in the volatile and nonvolatile fractions of preen secretion and preen down feathers. These results suggest that kittiwake body odor may function as a signal associated with mate recognition. It further suggests that preen odor might broadcast the genetic makeup of individuals, and could be used in mate choice to assess the genetic compatibility of potential mates.

  3. Discovery and validation of sub-threshold genome-wide association study loci using epigenomic signatures.

    Science.gov (United States)

    Wang, Xinchen; Tucker, Nathan R; Rizki, Gizem; Mills, Robert; Krijger, Peter Hl; de Wit, Elzo; Subramanian, Vidya; Bartell, Eric; Nguyen, Xinh-Xinh; Ye, Jiangchuan; Leyton-Mange, Jordan; Dolmatova, Elena V; van der Harst, Pim; de Laat, Wouter; Ellinor, Patrick T; Newton-Cheh, Christopher; Milan, David J; Kellis, Manolis; Boyer, Laurie A

    2016-01-01

    Genetic variants identified by genome-wide association studies explain only a modest proportion of heritability, suggesting that meaningful associations lie 'hidden' below current thresholds. Here, we integrate information from association studies with epigenomic maps to demonstrate that enhancers significantly overlap known loci associated with the cardiac QT interval and QRS duration. We apply functional criteria to identify loci associated with QT interval that do not meet genome-wide significance and are missed by existing studies. We demonstrate that these 'sub-threshold' signals represent novel loci, and that epigenomic maps are effective at discriminating true biological signals from noise. We experimentally validate the molecular, gene-regulatory, cellular and organismal phenotypes of these sub-threshold loci, demonstrating that most sub-threshold loci have regulatory consequences and that genetic perturbation of nearby genes causes cardiac phenotypes in mouse. Our work provides a general approach for improving the detection of novel loci associated with complex human traits. PMID:27162171

  4. Meta-Analysis of Microarray Studies Reveals a Novel Hematopoietic Progenitor Cell Signature and Demonstrates Feasibility of Inter-Platform Data Integration

    OpenAIRE

    Sohal, Davendra; Yeatts, Andrew; Ye, Kenny; Pellagatti, Andrea; Zhou, Li; Pahanish, Perry; Mo, Yongkai; Bhagat, Tushar; Mariadason, John; Boultwood, Jacqueline; Melnick, Ari; Greally, John; Verma, Amit

    2008-01-01

    Microarray-based studies of global gene expression (GE) have resulted in a large amount of data that can be mined for further insights into disease and physiology. Meta-analysis of these data is hampered by technical limitations due to many different platforms, gene annotations and probes used in different studies. We tested the feasibility of conducting a meta-analysis of GE studies to determine a transcriptional signature of hematopoietic progenitor and stem cells. Data from studies that us...

  5. Study on scattering properties of tissues with hyperosmotic chemical agents

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Optical properties of biological tissue are variable due to the changes of micro-structures and scattering constituents after hyperosmotic chemical agents permeates into tissue. The changes of optical properties of biological tissue are due to the refractive indices matching between the scatterers with high refractive index and the ground substances, which reduce scattering of tissue. The main reasons are that permeated semipermeable chemical agents with higher refractive index than the ground substances of tissuemakes the refractive index of ground substances of tissue higher by the enhancement of the permeated concentration. We studied on the collimated transmittance changes of light penetrating biological tissue after the hyperosmotic chemical agents administrates with different concentration.

  6. Signatures of protein thermal denaturation and local hydrophobicity in domain specific hydration behavior: a comparative molecular dynamics study.

    Science.gov (United States)

    Chatterjee, Prathit; Sengupta, Neelanjana

    2016-04-22

    We investigate, using atomistic molecular dynamics simulations, the association of surface hydration accompanying local unfolding in the mesophilic protein Yfh1 under a series of thermal conditions spanning its cold and heat denaturation temperatures. The results are benchmarked against the thermally stable protein, Ubq, and behavior at the maximum stability temperature. Local unfolding in Yfh1, predominantly in the beta sheet regions, is in qualitative agreement with recent solution NMR studies; the corresponding Ubq unfolding is not observed. Interestingly, all domains, except for the beta sheet domains of Yfh1, show increased effective surface hydrophobicity with increase in temperature, as reflected by the density fluctuations of the hydration layer. Velocity autocorrelation functions (VACF) of oxygen atoms of water within the hydration layers and the corresponding vibrational density of states (VDOS) are used to characterize alteration in dynamical behavior accompanying the temperature dependent local unfolding. Enhanced caging effects accompanying transverse oscillations of the water molecules are found to occur with the increase in temperature preferentially for the beta sheet domains of Yfh1. Helical domains of both proteins exhibit similar trends in VDOS with changes in temperature. This work demonstrates the existence of key signatures of the local onset of protein thermal denaturation in solvent dynamical behavior. PMID:26876051

  7. Using unsupervised neural networks for eddy currents signature discrimination: a prospective study

    International Nuclear Information System (INIS)

    This report describes an application of unsupervised neural networks for eddy currents Non Destructive Testing (NDT) inspection of steam generator tubes. As a matter of fact conventional neurocomputing techniques (multilayer perceptions) fail to achieve desired results because of the inherent lack of data and the slowly changing characteristics involved. This is an original neural approach to defect detection, characterized by two aspects: diagnosis is expressed in architectural terms and the potential advantages of using unsupervised neural techniques are systematically discussed. After briefly recalling the context and origin of the study, we present the framework of the Kohonen self organizing maps within the proposed diagnosis architecture. We then show how we intend to use them for sound/unsound discrimination compliant with eddy currents NDT requirements. Preliminary results are presented in the last part of the report. They seem confirm that this new approach is worth being more deeply investigated. (author). 13 figs., 17 refs., 3 annexes

  8. An extended data mining method for identifying differentially expressed assay-specific signatures in functional genomic studies

    Directory of Open Access Journals (Sweden)

    Rollins Derrick K

    2010-12-01

    Full Text Available Abstract Background Microarray data sets provide relative expression levels for thousands of genes for a small number, in comparison, of different experimental conditions called assays. Data mining techniques are used to extract specific information of genes as they relate to the assays. The multivariate statistical technique of principal component analysis (PCA has proven useful in providing effective data mining methods. This article extends the PCA approach of Rollins et al. to the development of ranking genes of microarray data sets that express most differently between two biologically different grouping of assays. This method is evaluated on real and simulated data and compared to a current approach on the basis of false discovery rate (FDR and statistical power (SP which is the ability to correctly identify important genes. Results This work developed and evaluated two new test statistics based on PCA and compared them to a popular method that is not PCA based. Both test statistics were found to be effective as evaluated in three case studies: (i exposing E. coli cells to two different ethanol levels; (ii application of myostatin to two groups of mice; and (iii a simulated data study derived from the properties of (ii. The proposed method (PM effectively identified critical genes in these studies based on comparison with the current method (CM. The simulation study supports higher identification accuracy for PM over CM for both proposed test statistics when the gene variance is constant and for one of the test statistics when the gene variance is non-constant. Conclusions PM compares quite favorably to CM in terms of lower FDR and much higher SP. Thus, PM can be quite effective in producing accurate signatures from large microarray data sets for differential expression between assays groups identified in a preliminary step of the PCA procedure and is, therefore, recommended for use in these applications.

  9. Unique proteomic signature for radiation sensitive patients; a comparative study between normo-sensitive and radiation sensitive breast cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Skiöld, Sara [Center for Radiation Protection Research, Department of Molecular Biosciences, The Wernner-Gren Institute, Stockholm University, Stockholm (Sweden); Azimzadeh, Omid [Institute of Radiation Biology, German Research Center for Environmental Health, Helmholtz Zentrum München (Germany); Merl-Pham, Juliane [Research Unit Protein Science, German Research Center for Environmental Health, Helmholtz Zentrum München, Neuherberg (Germany); Naslund, Ingemar; Wersall, Peter; Lidbrink, Elisabet [Division of Radiotherapy, Radiumhemmet, Karolinska University Hospital, Stockholm (Sweden); Tapio, Soile [Institute of Radiation Biology, German Research Center for Environmental Health, Helmholtz Zentrum München (Germany); Harms-Ringdahl, Mats [Center for Radiation Protection Research, Department of Molecular Biosciences, The Wernner-Gren Institute, Stockholm University, Stockholm (Sweden); Haghdoost, Siamak, E-mail: Siamak.Haghdoost@su.se [Center for Radiation Protection Research, Department of Molecular Biosciences, The Wernner-Gren Institute, Stockholm University, Stockholm (Sweden)

    2015-06-15

    Highlights: • The unique protein expression profiles were found that separate radiosensitive from normal sensitive breast cancer patients. • The oxidative stress response, coagulation properties and acute phase response suggested to be the hallmarks of radiation sensitivity. - Abstract: Radiation therapy is a cornerstone of modern cancer treatment. Understanding the mechanisms behind normal tissue sensitivity is essential in order to minimize adverse side effects and yet to prevent local cancer reoccurrence. The aim of this study was to identify biomarkers of radiation sensitivity to enable personalized cancer treatment. To investigate the mechanisms behind radiation sensitivity a pilot study was made where eight radiation-sensitive and nine normo-sensitive patients were selected from a cohort of 2914 breast cancer patients, based on acute tissue reactions after radiation therapy. Whole blood was sampled and irradiated in vitro with 0, 1, or 150 mGy followed by 3 h incubation at 37 °C. The leukocytes of the two groups were isolated, pooled and protein expression profiles were investigated using isotope-coded protein labeling method (ICPL). First, leukocytes from the in vitro irradiated whole blood from normo-sensitive and extremely sensitive patients were compared to the non-irradiated controls. To validate this first study a second ICPL analysis comparing only the non-irradiated samples was conducted. Both approaches showed unique proteomic signatures separating the two groups at the basal level and after doses of 1 and 150 mGy. Pathway analyses of both proteomic approaches suggest that oxidative stress response, coagulation properties and acute phase response are hallmarks of radiation sensitivity supporting our previous study on oxidative stress response. This investigation provides unique characteristics of radiation sensitivity essential for individualized radiation therapy.

  10. Unique proteomic signature for radiation sensitive patients; a comparative study between normo-sensitive and radiation sensitive breast cancer patients

    International Nuclear Information System (INIS)

    Highlights: • The unique protein expression profiles were found that separate radiosensitive from normal sensitive breast cancer patients. • The oxidative stress response, coagulation properties and acute phase response suggested to be the hallmarks of radiation sensitivity. - Abstract: Radiation therapy is a cornerstone of modern cancer treatment. Understanding the mechanisms behind normal tissue sensitivity is essential in order to minimize adverse side effects and yet to prevent local cancer reoccurrence. The aim of this study was to identify biomarkers of radiation sensitivity to enable personalized cancer treatment. To investigate the mechanisms behind radiation sensitivity a pilot study was made where eight radiation-sensitive and nine normo-sensitive patients were selected from a cohort of 2914 breast cancer patients, based on acute tissue reactions after radiation therapy. Whole blood was sampled and irradiated in vitro with 0, 1, or 150 mGy followed by 3 h incubation at 37 °C. The leukocytes of the two groups were isolated, pooled and protein expression profiles were investigated using isotope-coded protein labeling method (ICPL). First, leukocytes from the in vitro irradiated whole blood from normo-sensitive and extremely sensitive patients were compared to the non-irradiated controls. To validate this first study a second ICPL analysis comparing only the non-irradiated samples was conducted. Both approaches showed unique proteomic signatures separating the two groups at the basal level and after doses of 1 and 150 mGy. Pathway analyses of both proteomic approaches suggest that oxidative stress response, coagulation properties and acute phase response are hallmarks of radiation sensitivity supporting our previous study on oxidative stress response. This investigation provides unique characteristics of radiation sensitivity essential for individualized radiation therapy

  11. IR signature study of aircraft engine for variation in nozzle exit area

    Science.gov (United States)

    Baranwal, Nidhi; Mahulikar, Shripad P.

    2016-01-01

    In general, jet engines operate with choked nozzle during take-off, climb and cruise, whereas unchoking occurs while landing and taxiing (when engine is not running at full power). Appropriate thrust in an aircraft in all stages of the flight, i.e., take-off, climb, cruise, descent and landing is achieved through variation in the nozzle exit area. This paper describes the effect on thrust and IR radiance of a turbojet engine due to variation in the exit area of a just choked converging nozzle (Me = 1). The variations in the nozzle exit area result in either choking or unchoking of a just choked converging nozzle. Results for the change in nozzle exit area are analyzed in terms of thrust, mass flow rate and specific fuel consumption. The solid angle subtended (Ω) by the exhaust system is estimated analytically, for the variation in nozzle exit area (Ane), as it affects the visibility of the hot engine parts from the rear aspect. For constant design point thrust, IR radiance is studied from the boresight (ϕ = 0°, directly from the rear side) for various percentage changes in nozzle exit area (%ΔAne), in the 1.9-2.9 μm and 3-5 μm bands.

  12. The neural signature of the Fraser illusion: An explorative EEG study on Fraser-like displays

    Directory of Open Access Journals (Sweden)

    Xuyan Yun

    2015-07-01

    Full Text Available We studied neural correlates accompanying the Fraser spiral illusion. The Fraser spiral illusion consists of twisted cords superimposed on a patchwork background arranged in concentric circles, which is typically perceived as a spiral. We tested four displays: the Fraser spiral illusion and three variants derived from it by orthogonally combining featural properties. In our stimuli, the shape of the cords comprised either concentric circles or a single spiral. The cords themselves consisted of black and white lines in parallel to the contour of the cords (i.e. parallel cords, or oblique line elements (i.e. twisted cords. The displays with twisted cords successfully induced illusory percepts, i.e. circles looked like spirals (the Fraser spiral illusion and spirals looked like circles (i.e., a ‘reverse Fraser illusion’. We compared the event-related potentials in a Stimulus (Circle, Spiral × Percept (Circle, Spiral design. A significant main effect of Stimulus was found at the posterior scalp in an early component (P220-280 and a significant main effect of Percept was found over the anterior scalp in a later component (P350-450. Although the EEG data suggest stimulus-based processing in posterior area in an early time window and Percept based processing in the later time window, an overall clear-cut stimulus-percept segregation was not found due to additional interaction effects. Instead, the data, especially in the later time window in the anterior area, point at differential processing for the condition comprising circle shapes but spiral percepts (i.e. the Fraser illusion.

  13. DNA-based Nanoconstructs for the Detection of Ions and Biomolecules with Related Raman/SERS Signature Studies

    Science.gov (United States)

    Brenneman, Kimber L.

    The utilization of DNA aptamers and semiconductor quantum dots (QDs) for the detection of ions and biomolecules was investigated. In recent years, there have been many studies based on the use of DNA and RNA aptamers, which are single stranded oligonucleotides capable of binding to biomolecules, other molecules, and ions. In many of these cases, the conformational changes of these DNA and RNA aptamers are suitable to use fluorescence resonant energy transfer (FRET) or nanometal surface energy transfer (NSET) techniques to detect such analytes. Coupled with this growth in such uses of aptamers, there has been an expanded use of semiconductor quantum dots as brighter, longer-lasting alternatives to fluorescent dyes in labeling and detection techniques of interest in biomedicine and environmental monitoring. Thrombin binding aptamer (TBA) and a zinc aptamer were used to detect mercury, lead, zinc, and cadmium. These probes were tested in a liquid assay as well as on a filter paper coupon. Biomolecules were also studied and detected using surface-enhanced Raman spectroscopy (SERS), including DNA aptamers and C-reactive protein (CRP). Raman spectroscopy is a useful tool for sensor development, label-free detection, and has the potential for remote sensing. Raman spectra provide information on the vibrational modes or phonons, between and within molecules. Therefore, unique spectral fingerprints for single molecules can be obtained. SERS is accomplished through the use of substrates with nanometer scale geometries made of metals with many free electrons, such as silver, gold, or copper. In this research silver SERS substrates were used to study the SERS signature of biomolecules that typically produce very weak Raman signals.

  14. A chemical EOR benchmark study of different reservoir simulators

    Science.gov (United States)

    Goudarzi, Ali; Delshad, Mojdeh; Sepehrnoori, Kamy

    2016-09-01

    chemical design for field-scale studies using commercial simulators. The benchmark tests illustrate the potential of commercial simulators for chemical flooding projects and provide a comprehensive table of strengths and limitations of each simulator for a given chemical EOR process. Mechanistic simulations of chemical EOR processes will provide predictive capability and can aid in optimization of the field injection projects. The objective of this paper is not to compare the computational efficiency and solution algorithms; it only focuses on the process modeling comparison.

  15. Qualified Mobile Server Signature

    OpenAIRE

    Orthacker, Clemens; Centner, Martin; Kittl, Christian

    2010-01-01

    International audience A legal basis for the use of electronic signatures exists since the introduction of qualified electronic signatures in EU Directive 1999/ 93/EC. Although considered as key enablers for e-Government and e-Commerce, qualified electronic signatures are still not widely used. Introducing amobile component addresses most of the shortcomings of existing qualified signature approaches but poses certain difficulties in the security reasoning. The proposed server based mobile...

  16. Efficient Threshold Signature Scheme

    Directory of Open Access Journals (Sweden)

    Sattar J Aboud

    2012-01-01

    Full Text Available In this paper, we introduce a new threshold signature RSA-typed scheme. The proposed scheme has the characteristics of un-forgeable and robustness in random oracle model. Also, signature generation and verification is entirely non-interactive. In addition, the length of the entity signature participate is restricted by a steady times of the length of the RSA signature modulus. Also, the signing process of the proposed scheme is more efficient in terms of time complexity and interaction.

  17. 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

  18. Impurity Profiling of a Chemical Weapon Precursor for Possible Forensic Signatures by Comprehensive Two-Dimensional Gas Chromatography/Mass Spectrometry and Chemometrics

    Energy Technology Data Exchange (ETDEWEB)

    Hoggard, Jamin C.; Wahl, Jon H.; Synovec, Robert E.; Mong, Gary M.; Fraga, Carlos G.

    2010-01-15

    In this work we present the feasibility of using analytical chemical and chemometric methodologies to reveal and exploit the organic impurity profiles from commercial dimethyl methylphosphonate (DMMP) samples to illustrate the type of forensic information that may be obtained from chemical-attack evidence. Using DMMP as a model compound for a toxicant that may be used in a chemical attack, we used comprehensive two-dimensional gas chromatography mass spectrometric detection (GC × GC-TOFMS) to detect and identify trace organic impurities in six samples of commercially acquired DMMP. The GC x GC-TOFMS data were analyzed to produce impurity profiles for all six DMMP samples using 29 analyte impurities. The use of PARAFAC for the mathematical resolution of overlap GC x GC peaks ensured clean spectra for the identification of many of the detected analytes by spectral library matching. The use of statistical pairwise comparison revealed that there were trace impurities that were quantitatively similar and different among five of the six DMMP samples. Two of the DMMP samples were revealed to have identical impurity profiles by this approach. The use of nonnegative matrix factorization proved that there were five distinct DMMP sample types as illustrated by the clustering of the multiple DMMP analyses into 5 distinct clusters in the scores plots. The two indistinguishable DMMP samples were confirmed by their chemical supplier to be from the same bulk source. Sample information from the other chemical suppliers supported that the other five DMMP samples were likely from different bulk sources. These results demonstrate that the matching of synthesized products from the same source is possible using impurity profiling. In addition, the identified impurities common to all six DMMP samples provide strong evidence that basic route information can be obtained from impurity profiles. In addition, impurities that may be unique to the sole bulk manufacturer of DMMP were found in

  19. Weight loss predictability by plasma metabolic signatures in adults with obesity and morbid obesity of the DiOGenes study

    NARCIS (Netherlands)

    J.H.M. Stroeve; E. Saccenti; J. Bouwman; A. Dane; K. Strassburg; J. Vervoort; T. Hankemeier; A. Astrup; A.K. Smilde; B. van Ommen; W.H.M. Saris

    2016-01-01

    OBJECTIVE: Aim is to predict successful weight loss by metabolic signatures at baseline and to identify which differences in metabolic status may underlie variations in weight loss success. METHODS: In DiOGenes, a randomized, controlled trial, weight loss was induced using a low-calorie diet (800 kc

  20. Indicators and signatures

    International Nuclear Information System (INIS)

    Full text: The goal of this presentation is to give an idea of the methodology used to deal with proliferation problems. It can be useful for chemical, biological, balistical proliferation. Here, we underline nuclear proliferation scenarios. Nevertheless, the overall approach is also similar to activities related to terrorism. Everyone knows that to strengthen the NPT/IAEA safeguards and similar treaties verification protocols, the organisations in charge need to build strong capabilities to assess known situations and also to prepare themselves to unknown, or undeclared events and activities. To accomplish this, to collect, analyze, build ad hoc knowledge, organisations have to select the information, to manage the enormous amount of available data. Rather recently, the emergence of new crisis has confirmed the central and vital role that information processing plays at each levels of the international or national non-proliferation community. It is why looking for indicators and signatures is so important, to focus on pertinent information, that could mean something from a nuclear proliferation perspective. This allows people dealing with nuclear proliferation not to be overwhelmed by tons of paper or G bites of memory. A strong need for expertise. Identifying, select and following indicators or looking for signatures is not an easy task. It requires strong expertise. From the development and maintenance of its nuclear deterrence, France acquired expertise in the design, production of fissile material, manufacture and testing of nuclear weapons. There is also in France a long history of nuclear achievements, with small or large scale facilities, both in civilian and military fields; each step of the nuclear fuel cycle can be very precisely described. French nuclear technical assessment relies on Commissariat a l'Energie Atomique (CEA, i.e. Atomic Energy Commission). Since 1958, CEA laboratories are in charge of nuclear civilian and military applications. Other

  1. Oxygen isotopic signature of CO2 from combustion processes

    Directory of Open Access Journals (Sweden)

    W. A. Brand

    2011-02-01

    Full Text Available For a comprehensive understanding of the global carbon cycle precise knowledge of all processes is necessary. Stable isotope (13C and 18O abundances provide information for the qualification and the quantification of the diverse source and sink processes. This study focuses on the δ18O signature of CO2 from combustion processes, which are widely present both naturally (wild fires, and human induced (fossil fuel combustion, biomass burning in the carbon cycle. All these combustion processes use atmospheric oxygen, of which the isotopic signature is assumed to be constant with time throughout the whole atmosphere. The combustion is generally presumed to take place at high temperatures, thus minimizing isotopic fractionation. Therefore it is generally supposed that the 18O signature of the produced CO2 is equal to that of the atmospheric oxygen. This study, however, reveals that the situation is much more complicated and that important fractionation effects do occur. From laboratory studies fractionation effects on the order of up to 26%permil; became obvious in the derived CO2 from combustion of different kinds of material, a clear differentiation of about 7‰ was also found in car exhausts which were sampled directly under ambient atmospheric conditions. We investigated a wide range of materials (both different raw materials and similar materials with different inherent 18O signature, sample geometries (e.g. texture and surface-volume ratios and combustion circumstances. We found that the main factor influencing the specific isotopic signatures of the combustion-derived CO2 and of the concomitantly released oxygen-containing side products, is the case-specific rate of combustion. This points firmly into the direction of (diffusive transport of oxygen to the reaction zone as the cause of the isotope fractionation. The original total 18O signature of the material appeared to have little influence, however, a contribution of specific bio-chemical

  2. Oxygen isotopic signature of CO2 from combustion processes

    Science.gov (United States)

    Schumacher, M.; Werner, R. A.; Meijer, H. A. J.; Jansen, H. G.; Brand, W. A.; Geilmann, H.; Neubert, R. E. M.

    2011-02-01

    For a comprehensive understanding of the global carbon cycle precise knowledge of all processes is necessary. Stable isotope (13C and 18O) abundances provide information for the qualification and the quantification of the diverse source and sink processes. This study focuses on the δ18O signature of CO2 from combustion processes, which are widely present both naturally (wild fires), and human induced (fossil fuel combustion, biomass burning) in the carbon cycle. All these combustion processes use atmospheric oxygen, of which the isotopic signature is assumed to be constant with time throughout the whole atmosphere. The combustion is generally presumed to take place at high temperatures, thus minimizing isotopic fractionation. Therefore it is generally supposed that the 18O signature of the produced CO2 is equal to that of the atmospheric oxygen. This study, however, reveals that the situation is much more complicated and that important fractionation effects do occur. From laboratory studies fractionation effects on the order of up to 26%permil; became obvious in the derived CO2 from combustion of different kinds of material, a clear differentiation of about 7‰ was also found in car exhausts which were sampled directly under ambient atmospheric conditions. We investigated a wide range of materials (both different raw materials and similar materials with different inherent 18O signature), sample geometries (e.g. texture and surface-volume ratios) and combustion circumstances. We found that the main factor influencing the specific isotopic signatures of the combustion-derived CO2 and of the concomitantly released oxygen-containing side products, is the case-specific rate of combustion. This points firmly into the direction of (diffusive) transport of oxygen to the reaction zone as the cause of the isotope fractionation. The original total 18O signature of the material appeared to have little influence, however, a contribution of specific bio-chemical compounds to

  3. Quantum chemical studies of epoxide-transforming enzymes

    OpenAIRE

    Hopmann, Kathrin H.

    2007-01-01

    Density functional theory is employed to study the reaction mechanisms of different epoxide-transforming enzymes. Calculations are based on quantum chemical active site models, which are build from X-ray crystal structures. The models are used to study conversion of various epoxides into their corresponding diols or substituted alcohols. Epoxide-transforming enzymes from three different families are studied. The human soluble epoxide hydrolase (sEH) belongs to the α/β-hydrolase fold family. s...

  4. Disaster relief through composite signatures

    Science.gov (United States)

    Hawley, Chadwick T.; Hyde, Brian; Carpenter, Tom; Nichols, Steve

    2012-06-01

    A composite signature is a group of signatures that are related in such a way to more completely or further define a target or operational endeavor at a higher fidelity. This paper builds on previous work developing innovative composite signatures associated with civil disasters, including physical, chemical and pattern/behavioral. For the composite signature approach to be successful it requires effective data fusion and visualization. This plays a key role in both preparedness and the response and recovery which are critical to saving lives. Visualization tools enhance the overall understanding of the crisis by pulling together and analyzing the data, and providing a clear and complete analysis of the information to the organizations/agencies dependant on it for a successful operation. An example of this, Freedom Web, is an easy-to-use data visualization and collaboration solution for use in homeland security, emergency preparedness, situational awareness, and event management. The solution provides a nationwide common operating picture for all levels of government through a web based, map interface. The tool was designed to be utilized by non-geospatial experts and is easily tailored to the specific needs of the users. Consisting of standard COTS and open source databases and a web server, users can view, edit, share, and highlight information easily and quickly through a standard internet browser.

  5. Quantum threshold group signature

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In most situations, the signer is generally a single person. However, when the message is written on behalf of an organization, a valid message may require the approval or consent of several persons. Threshold signature is a solution to this problem. Generally speaking, as an authority which can be trusted by all members does not exist, a threshold signature scheme without a trusted party appears more attractive. Following some ideas of the classical Shamir’s threshold signature scheme, a quantum threshold group signature one is proposed. In the proposed scheme, only t or more of n persons in the group can generate the group signature and any t-1 or fewer ones cannot do that. In the verification phase, any t or more of n signature receivers can verify the message and any t-1 or fewer receivers cannot verify the validity of the signature.

  6. [Scanning electron microscope study of chemically disinfected endodontic files].

    Science.gov (United States)

    Navarro, G; Mateos, M; Navarro, J L; Canalda, C

    1991-01-01

    Forty stainless steel endodontic files were observed at scanning electron microscopy after being subjected to ten disinfection cycles of 10 minutes each one, immersed in different chemical disinfectants. Corrosion was not observed on the surface of the files in circumstances that this study was made. PMID:1659857

  7. An examination of quantitative methods for Forensic Signature Analysis and the admissibility of signature verification system as legal evidence.

    OpenAIRE

    Chatzisterkotis, Thomas

    2015-01-01

    The experiments described in this thesis deal with handwriting characteristics which are involved in the production of forged and genuine signatures and complexity of signatures. The objectives of this study were (1) to provide sufficient details on which of the signature characteristics are easier to forge, (2) to investigate the capabilities of the signature complexity formula given by Found et al. based on a different signature database provided by University of Kent. This database includes ...

  8. Topics on Galactic Chemical Evolution

    OpenAIRE

    Prantzos, Nikos

    2011-01-01

    I discuss three different topics in Galactic chemical evolution:the "puzzling" absence of any observational signature of secondary elements ; the building of the Galactic halo in the framework of hierarchical galaxy formation, as evidenced from its metallicity distribution ; and the potentially important role that radial migration may play in the evolution of galactic disks, according to recent studies.

  9. Health effects of chemical pollution: case-study in Algeria

    International Nuclear Information System (INIS)

    The analysis of some biological parameters of workers in a factory producing chemical fertilizers ASMIDAL (Algeria), and of residents a nearby city (El Bouni) who are exposed to the smell of chemical pollution, shows modifications of these parameters in terms of contamination due to nitric derivatives. The rat ingestion of infra-lethal dose of ammonium nitrate produced by ASMIDAL provokes modifications which are similar to those found in the subjects studied in this work. These modifications are of main concern to the levels of hemoglobin, methemoglobin, erythrocytes, seric and urinary nitrates. In addition, modifications in the activity of the spleen and of the liver have been observed in the rat. (author)

  10. Chemical and preclinical studies on Hedyotis diffusa with anticancer potential.

    Science.gov (United States)

    Niu, Yu; Meng, Qiu-Xia

    2013-01-01

    This paper presents the chemical and preclinical anticancer research on Hedyotis diffusa Willd. in detail, one of the most renowned herbs often prescribed in the polyherbal formulas for cancer treatment in traditional Chinese medicine. Anthraquinones, flavonoids, and terpenoids constitute the majority of the 69 compounds that have been isolated and identified from H. diffusa. The anticancer effects of the methanolic, ethanolic, and aqueous extracts in various preclinical cancer models have been described. This review also summarized the anticancer activity of constituents of the herb and the mechanisms of action. All the studies suggest that H. diffusa has enormous potential in the therapy of cancer and warrants further chemical and pharmacological investigation. PMID:23600735

  11. Chemical separation procedure proposed for studies of bohrium

    International Nuclear Information System (INIS)

    Off-line and on-line studies have been performed with radioactive tracers of various elements to develop a chemical separation procedure for bohrium (element 107). The proposed procedure is intended for use in the fast solvent extraction system SISAK. The homologs technetium and rhenium were used to model the chemical behavior of bohrium. The results show that high decontamination factors can be obtained for technetium and rhenium with respect to unwanted contaminants like trivalent actinides, polonium and the Group 5 elements. (author)

  12. Preliminary study of chemical compositional data from Amazon ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Toyota, Rosimeiri G.; Munita, Casimiro S.; Luz, Fabio A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: rosimeiritoy@yahoo.com.br; Neves, Eduardo G. [Museu de Arqueologia e Etnolgia, Sao Paulo, SP (Brazil)]. E-mail: egneves@usp.br; Oliveira, Paulo M.S. [Sao Paulo Univ., SP (Brazil). Escola Politecnica. Inst. de Matematica e Estatistica]. E-mail: poliver@usp.br

    2005-07-01

    Eighty seven ceramic samples from Acutuba, Lago Grande and Osvaldo archaeological sites located in the confluence of the rivers Negro and Solimoes were submitted to chemical analysis using instrumental neutron activation analysis to determine As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Rb, Na, Nd, Sb, Sc, Sm, Ta, Tb, Th, Yb, Zn, and U. The database were studied using the Mahalanobis distance, and discriminant analysis. The results showed that the ceramics of each site differ from each other in chemical composition and that they form three different groups. Chemical classification of the ceramics suggests that vessels were made locally, as only ceramics from the same area show homogeneity of data. (author)

  13. Preliminary study of chemical compositional data from Amazon ceramics

    International Nuclear Information System (INIS)

    Eighty seven ceramic samples from Acutuba, Lago Grande and Osvaldo archaeological sites located in the confluence of the rivers Negro and Solimoes were submitted to chemical analysis using instrumental neutron activation analysis to determine As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Rb, Na, Nd, Sb, Sc, Sm, Ta, Tb, Th, Yb, Zn, and U. The database were studied using the Mahalanobis distance, and discriminant analysis. The results showed that the ceramics of each site differ from each other in chemical composition and that they form three different groups. Chemical classification of the ceramics suggests that vessels were made locally, as only ceramics from the same area show homogeneity of data. (author)

  14. Detection of the spectroscopic signatures of explosives and their degradation products

    Science.gov (United States)

    Florian, Vivian; Cabanzo, Andrea; Baez, Bibiana; Correa, Sandra; Irrazabal, Maik; Briano, Julio G.; Castro, Miguel E.; Hernandez-Rivera, Samuel P.

    2005-06-01

    Detection and removal of antipersonnel and antitank landmines is a great challenge and a worldwide enviromental and humanitarian problem. Sensors tuned on the spectroscopic signature of the chemicals released from mines are a potential solution. Enviromental factors (temperature, relative humidity, rainfall precipitation, wind, sun irradiation, pressure, etc.) as well as soil characteristics (water content, compaction, porosity, chemical composition, particle size distribution, topography, vegetation, etc), have a direct impact on the fate and transport of the chemicals released from landmines. Chemicals such as TNT, DNT and their degradation products, are semi-volatile, and somewhat soluble in water. Also, they may adsorb strongly to soil particles, and are susceptible to degradation by microorganisms, light, or chemical agents. Here we show an experimental procedure to quantify the effect of the above variables on the spectroscopic signature. A number of soil tanks under controlled conditions are used to study the effect of temperature, water content, relative humidity and light radiation.

  15. Application of CWC analytical procedures for safeguards; Analysis of phosphorus-containing organic chemical signatures from environmental samples; Final report on task FIN A844 on the Finnish support programme to IAEA safeguards

    International Nuclear Information System (INIS)

    Solvent extraction can be used for the recovery of U and Pu from irradiated fuel. The most potential organic chemical signatures are extractants and solvents used in reprocessing plants. The PUREX process is widely used in reprocessing. It uses tri-n-butyl phosphate (TBP) as extractant in an organic solvent for U and Pu from irradiated fuel and U from its ores. TBP is a strong extractant for tetra and hexavalent actinides from nitric acid media. Stable complexes are formed between actinide nitrate and TBP which are soluble in the organic phase. Sample containing TBP and some radiolysis products can indicate that TBP is used for reprocessing nuclear fuel. The TBP will decompose in the PUREX process to mono-and dibutyl phosphates (MBP and DBP). TBP, DBP and MBP have been analysed from air, water, soil, and sediment samples according to slightly modified procedures presented in Recommended Operating Procedures for Sampling and Analysis in the Verification of Chemical Disarmament. The limits of detection for the phosphates have been determined for air, water and soil samples. (orig.) (12 refs., 8 figs., 4 tabs.)

  16. Application of CWC analytical procedures for safeguards; Analysis of phosphorus-containing organic chemical signatures from environmental samples; Final report on task FIN A844 on the Finnish support programme to IAEA safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Rautio, M.; Bjoerk, H.; Haekkinen, V.; Kostiainen, O.; Kuitunen, M.L.; Lehtonen, P.; Mesilaakso, M.; Soederstroem, M. [Finnish Inst. for Verification of the Chemical Weapons Convention, Helsinki (Finland)

    1995-03-01

    Solvent extraction can be used for the recovery of U and Pu from irradiated fuel. The most potential organic chemical signatures are extractants and solvents used in reprocessing plants. The PUREX process is widely used in reprocessing. It uses tri-n-butyl phosphate (TBP) as extractant in an organic solvent for U and Pu from irradiated fuel and U from its ores. TBP is a strong extractant for tetra and hexavalent actinides from nitric acid media. Stable complexes are formed between actinide nitrate and TBP which are soluble in the organic phase. Sample containing TBP and some radiolysis products can indicate that TBP is used for reprocessing nuclear fuel. The TBP will decompose in the PUREX process to mono-and dibutyl phosphates (MBP and DBP). TBP, DBP and MBP have been analysed from air, water, soil, and sediment samples according to slightly modified procedures presented in Recommended Operating Procedures for Sampling and Analysis in the Verification of Chemical Disarmament. The limits of detection for the phosphates have been determined for air, water and soil samples. (orig.) (12 refs., 8 figs., 4 tabs.).

  17. Study of the chemical sputtering in Tore-Supra

    International Nuclear Information System (INIS)

    The work presented in this thesis focuses on the interactions between energetic particles coming from thermonuclear plasma and the inner components of a fusion machine. This interaction induces two major problems: erosion of the wall, and tritium retention. This report treats the erosion of carbon based materials. The first part is devoted to chemical sputtering, that appears to be the principal erosion mechanism, compared to physical sputtering and radiation enhanced sublimation that both can be limited. Chemical sputtering has been studied in situ in the tokamak Tore-Supra for ohmic and lower hybrid (LH) heated discharges, by means of mass spectrometry and optical spectroscopy. We have shown that it is necessary to take into account both methane and heavier hydrocarbons (C2Dx and C3Dy) in the determination of the chemical sputtering yield. It is found that for the ohmic discharges, the sputtering yield of CD4 (YCD4) is highly flux (φ) dependent, showing a variation of the form: YCD4 ∝ φ-0.23. The experimental study also reveals that an increase of the surface temperature induces an augmentation of YCD4. The interpretation and the modelling of the experimental results have been performed with a Monte Carlo code (BBQ. In the second part of this work, we have developed and installed an infrared spectroscopy diagnostic in the 0.8-1.6, μm wavelength range dedicated to the measurement of surface temperature, and the identification of atomic and molecular lines emitted during plasma/wall interactions. In the third part, we present the feasibility study of an in situ tungsten deposition process at low temperature(<80 deg C) in order to suppress the chemical sputtering. This study shows that, with this method call Plasma Assisted Chemical Vapor Deposition (PACVD), we are able to coat the whole inner vessel of a tokamak with 1 μm of tungsten. (author)

  18. Studying chemical reactions in biological systems with MBN Explorer

    DEFF Research Database (Denmark)

    Sushko, Gennady B.; Solov'yov, Ilia A.; Verkhovtsev, Alexey V.;

    2016-01-01

    The concept of molecular mechanics force field has been widely accepted nowadays for studying various processes in biomolecular systems. In this paper, we suggest a modification for the standard CHARMM force field that permits simulations of systems with dynamically changing molecular topologies....... applied for studying processes where rupture of chemical bonds plays an essential role, e.g., in irradiation- or collision-induced damage, and also in transformation and fragmentation processes involving biomolecular systems....

  19. On reliable discovery of molecular signatures

    Directory of Open Access Journals (Sweden)

    Björkegren Johan

    2009-01-01

    Full Text Available Abstract Background Molecular signatures are sets of genes, proteins, genetic variants or other variables that can be used as markers for a particular phenotype. Reliable signature discovery methods could yield valuable insight into cell biology and mechanisms of human disease. However, it is currently not clear how to control error rates such as the false discovery rate (FDR in signature discovery. Moreover, signatures for cancer gene expression have been shown to be unstable, that is, difficult to replicate in independent studies, casting doubts on their reliability. Results We demonstrate that with modern prediction methods, signatures that yield accurate predictions may still have a high FDR. Further, we show that even signatures with low FDR may fail to replicate in independent studies due to limited statistical power. Thus, neither stability nor predictive accuracy are relevant when FDR control is the primary goal. We therefore develop a general statistical hypothesis testing framework that for the first time provides FDR control for signature discovery. Our method is demonstrated to be correct in simulation studies. When applied to five cancer data sets, the method was able to discover molecular signatures with 5% FDR in three cases, while two data sets yielded no significant findings. Conclusion Our approach enables reliable discovery of molecular signatures from genome-wide data with current sample sizes. The statistical framework developed herein is potentially applicable to a wide range of prediction problems in bioinformatics.

  20. Detailed Abundances of Planet-Hosting Wide Binaries. I. Did Planet Formation Imprint Chemical Signatures in the Atmospheres of HD 20782/81?

    CERN Document Server

    Mack, Claude E; Stassun, Keivan G; Pepper, Joshua; Norris, John

    2014-01-01

    Using high-resolution echelle spectra obtained with Magellan/MIKE, we present a chemical abundance analysis of both stars in the planet-hosting wide binary system HD20782 + HD20781. Both stars are G dwarfs, and presumably coeval, forming in the same molecular cloud. Therefore we expect that they should possess the same bulk metallicities. Furthermore, both stars also host giant planets on eccentric orbits with pericenters $\\lesssim 0.2\\,$ AU. We investigate if planets with such orbits could lead to the host stars ingesting material, which in turn may leave similar chemical imprints in their atmospheric abundances. We derived abundances of 15 elements spanning a range of condensation temperatures ($T_{C}\\approx 40-1660\\,$ K). The two stars are found to have a mean element-to-element abundance difference of $0.04\\pm0.07\\,$ dex, which is consistent with both stars having identical bulk metallicities. In addition, for both stars, the refractory elements ($T_{C} > 900\\,$ K) exhibit a positive correlation between a...

  1. Recent developments in the study of rapid human movements with the kinematic theory: Applications to handwriting and signature synthesis

    OpenAIRE

    Plamondon, Réjean; O’Reilly, Christian; Galbally, Javier; Almaksour, Abdullah; Anquetil, Éric

    2014-01-01

    International audience Human movement modeling can be of great interest for the design of pattern recognition systems relying on the understanding of the fine motor control (such as on-line handwriting recognition or signature verification) as well as for the development of intelligent systems involving in a way or another the processing of human movements. In this paper, we briefly list the different models that have been proposed in order to characterize the handwriting process and focus...

  2. Diacritical Seismic Signatures for Complex Geological Structures: Case Studies from Shushan Basin (Egypt) and Arkoma Basin (USA)

    OpenAIRE

    Abdel-Fattah, Mohamed I.; Hamed A. Alrefaee

    2014-01-01

    Seismic reflection techniques show an imperative role in imaging complex geological structures and are becoming more acceptable as data interpreting tools in 2D/3D view. These subsurface geological structures provide complex seismic signature due to their geometrical behavior. Consequently, it is extremely difficult to interpret these seismic sections in terms of subsurface configuration. The main goal of this paper is to introduce seismic attributes as a powerful tool to interpret complex ge...

  3. Uncertainty in hydrological signatures

    Science.gov (United States)

    Westerberg, I. K.; McMillan, H. K.

    2015-09-01

    Information about rainfall-runoff processes is essential for hydrological analyses, modelling and water-management applications. A hydrological, or diagnostic, signature quantifies such information from observed data as an index value. Signatures are widely used, e.g. for catchment classification, model calibration and change detection. Uncertainties in the observed data - including measurement inaccuracy and representativeness as well as errors relating to data management - propagate to the signature values and reduce their information content. Subjective choices in the calculation method are a further source of uncertainty. We review the uncertainties relevant to different signatures based on rainfall and flow data. We propose a generally applicable method to calculate these uncertainties based on Monte Carlo sampling and demonstrate it in two catchments for common signatures including rainfall-runoff thresholds, recession analysis and basic descriptive signatures of flow distribution and dynamics. Our intention is to contribute to awareness and knowledge of signature uncertainty, including typical sources, magnitude and methods for its assessment. We found that the uncertainties were often large (i.e. typical intervals of ±10-40 % relative uncertainty) and highly variable between signatures. There was greater uncertainty in signatures that use high-frequency responses, small data subsets, or subsets prone to measurement errors. There was lower uncertainty in signatures that use spatial or temporal averages. Some signatures were sensitive to particular uncertainty types such as rating-curve form. We found that signatures can be designed to be robust to some uncertainty sources. Signature uncertainties of the magnitudes we found have the potential to change the conclusions of hydrological and ecohydrological analyses, such as cross-catchment comparisons or inferences about dominant processes.

  4. Comparative quantitative study of 'signature' pathological lesions in the hippocampus and adjacent gyri of 12 neurodegenerative disorders.

    Science.gov (United States)

    Armstrong, Richard A; Cairns, Nigel J

    2015-10-01

    The hippocampus (HC) and adjacent gyri are implicated in dementia in several neurodegenerative disorders. To compare HC pathology among disorders, densities of 'signature' pathological lesions were measured at a standard location in eight brain regions of 12 disorders. Principal components analysis of the data suggested that the disorders could be divided into three groups: (1) Alzheimer's disease (AD), Down's syndrome (DS), sporadic Creutzfeldt-Jakob disease, and variant Creutzfeldt-Jakob disease in which either β-amyloid (Aβ) or prion protein deposits were distributed in all sectors of the HC and adjacent gyri, with high densities being recorded in the parahippocampal gyrus and subiculum; (2) Pick's disease, sporadic frontotemporal lobar degeneration with TDP-43 immunoreactive inclusions, and neuronal intermediate filament inclusion disease in which relatively high densities of neuronal cytoplasmic inclusions were present in the dentate gyrus (DG) granule cells; and (3) Parkinson's disease dementia, dementia with Lewy bodies, progressive supranuclear palsy, corticobasal degeneration, and multiple system atrophy in which densities of signature lesions were relatively low. Variation in density of signature lesions in DG granule cells and CA1 were the most important sources of neuropathological variation among disorders. Hence, HC and adjacent gyri are differentially affected in dementia reflecting either variation in vulnerability of hippocampal neurons to specific molecular pathologies or in the spread of pathological proteins to the HC. Information regarding the distribution of pathology could ultimately help to explain variations in different cognitive domains, such as memory, observed in various disorders. PMID:25929331

  5. Detailed abundances of planet-hosting wide binaries. I. Did planet formation imprint chemical signatures in the atmospheres of HD 20782/81?

    International Nuclear Information System (INIS)

    Using high-resolution, high signal-to-noise echelle spectra obtained with Magellan/MIKE, we present a detailed chemical abundance analysis of both stars in the planet-hosting wide binary system HD 20782 + HD 20781. Both stars are G dwarfs, and presumably coeval, forming in the same molecular cloud. Therefore we expect that they should possess the same bulk metallicities. Furthermore, both stars also host giant planets on eccentric orbits with pericenters ≲0.2 AU. Here, we investigate if planets with such orbits could lead to the host stars ingesting material, which in turn may leave similar chemical imprints in their atmospheric abundances. We derived abundances of 15 elements spanning a range of condensation temperature, T C ≈ 40-1660 K. The two stars are found to have a mean element-to-element abundance difference of 0.04 ± 0.07 dex, which is consistent with both stars having identical bulk metallicities. In addition, for both stars, the refractory elements (T C >900 K) exhibit a positive correlation between abundance (relative to solar) and T C, with similar slopes of ≈1×10–4 dex K–1. The measured positive correlations are not perfect; both stars exhibit a scatter of ≈5×10–5 dex K–1 about the mean trend, and certain elements (Na, Al, Sc) are similarly deviant in both stars. These findings are discussed in the context of models for giant planet migration that predict the accretion of H-depleted rocky material by the host star. We show that a simple simulation of a solar-type star accreting material with Earth-like composition predicts a positive—but imperfect—correlation between refractory elemental abundances and T C. Our measured slopes are consistent with what is predicted for the ingestion of 10-20 Earths by each star in the system. In addition, the specific element-by-element scatter might be used to distinguish between planetary accretion and Galactic chemical evolution scenarios.

  6. Search for new chemical elements and possibilities to synthesize transactinide isotopes for chemical studies

    International Nuclear Information System (INIS)

    Elements up to Z=112 as well as 114 and 116 are officially recognized as discovered and have been named. The current literature contains reports about the synthesis of all elements up to Z=118, meaning that more than 10% of all elements are members of the transactinide series with Z=104-118. Therefore, search experiments for the new elements with Z=119 and Z=120 have been performed. An important question for such experiments concerns the optimum choice of the nuclear reaction. While only one experiment has been conducted so far with the aim of discovering Z=119, already four experiments on the synthesis of Z=120 have been performed, all employing different reactions. Still, Z=119 and 120 are not yet announced as discovered. The situation using the TASCA experiments as an example and the perspectives for the discovery of new elements are studied. The optimum reactions leading to the relatively long-lived isotopes of the transactinides as they are frequently used in chemical studies of these elements, including elements which were not studied chemically to date are discussed

  7. A decontamination study of simulated chemical and biological agents

    International Nuclear Information System (INIS)

    A comprehensive decontamination scheme of the chemical and biological agents, including airborne agents and surface contaminating agents, is presented. When a chemical and biological attack occurs, it is critical to decontaminate facilities or equipments to an acceptable level in a very short time. The plasma flame presented here may provide a rapid and effective elimination of toxic substances in the interior air in isolated spaces. As an example, a reaction chamber, with the dimensions of a 22 cm diameter and 30 cm length, purifies air with an airflow rate of 5000 l/min contaminated with toluene, the simulated chemical agent, and soot from a diesel engine, the simulated aerosol for biological agents. Although the airborne agents in an isolated space are eliminated to an acceptable level by the plasma flame, the decontamination of the chemical and biological agents cannot be completed without cleaning surfaces of the facilities. A simulated sterilization study of micro-organisms was carried out using the electrolyzed ozone water. The electrolyzed ozone water very effectively kills endospores of Bacillus atrophaeus (ATCC 9372) within 3 min. The electrolyzed ozone water also kills the vegetative micro-organisms, fungi, and virus. The electrolyzed ozone water, after the decontamination process, disintegrates into ordinary water and oxygen without any trace of harmful materials to the environment

  8. Blind Collective Signature Protocol

    Directory of Open Access Journals (Sweden)

    Nikolay A. Moldovyan

    2011-06-01

    Full Text Available Using the digital signature (DS scheme specified by Belarusian DS standard there are designed the collective and blind collective DS protocols. Signature formation is performed simultaneously by all of the assigned signers, therefore the proposed protocols can be used also as protocols for simultaneous signing a contract. The proposed blind collective DS protocol represents a particular implementation of the blind multisignature schemes that is a novel type of the signature schemes. The proposed protocols are the first implementations of the multisignature schemes based on Belarusian signature standard.

  9. Unconditionally Secure Quantum Signatures

    Directory of Open Access Journals (Sweden)

    Ryan Amiri

    2015-08-01

    Full Text Available Signature schemes, proposed in 1976 by Diffie and Hellman, have become ubiquitous across modern communications. They allow for the exchange of messages from one sender to multiple recipients, with the guarantees that messages cannot be forged or tampered with and that messages also can be forwarded from one recipient to another without compromising their validity. Signatures are different from, but no less important than encryption, which ensures the privacy of a message. Commonly used signature protocols—signatures based on the Rivest–Adleman–Shamir (RSA algorithm, the digital signature algorithm (DSA, and the elliptic curve digital signature algorithm (ECDSA—are only computationally secure, similar to public key encryption methods. In fact, since these rely on the difficulty of finding discrete logarithms or factoring large primes, it is known that they will become completely insecure with the emergence of quantum computers. We may therefore see a shift towards signature protocols that will remain secure even in a post-quantum world. Ideally, such schemes would provide unconditional or information-theoretic security. In this paper, we aim to provide an accessible and comprehensive review of existing unconditionally securesecure signature schemes for signing classical messages, with a focus on unconditionally secure quantum signature schemes.

  10. Feasibility study of chemical stabilization of dredged marine sediment

    OpenAIRE

    FURLAN, Ana Paola; RAZAKAMANANTSOA, Andry; Liang, Yingjie; Deneele, Dimitri

    2015-01-01

    Chemical stabilization is one of techniques which can improve mechanical and hydraulic properties of dredged sediments. This paper presents an experimental study focused on different techniques of stabilization of dredged sediment from La Baule-Le Pouliguen (France). Dredged sediments are stabilized with lime, Portland cement and fly ash. Three mixes were produced and submitted to uniaxial compression strength (UCS), indirect tensile strength (ITS) and shear tests at different curing ages. In...

  11. Chemical elements in invertebrate orders for environmental quality studies

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Marcelo R.L.; Franca, Elvis J.; Paiva, Jose D.S.; Hazin, Clovis A., E-mail: marcelo_rlm@hotmail.com, E-mail: ejfranca@cnen.gov.br, E-mail: dan-paiva@hotmail.com, E-mail: chazin@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Fonseca, Felipe Y.; Fernandes, Elisabete A. de Nadai; Bacchi, Marcio A., E-mail: felipe-yamada@hotmail.com, E-mail: lis@cena.usp.br, E-mail: mabacchi@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

    2013-07-01

    Among the biomonitors of environmental quality, there is a lack of studies on using invertebrates to evaluate quantitatively chemical elements in ecosystems. This group of animals is quite numerous, widely distributed and adaptable to the most diverse environmental conditions. These features are very useful for the environmental quality assessment, as well as the several occurring insect-plant interactions performing essential functions in ecosystems. The objective of this work is to study the variability of chemical composition of invertebrate orders for using in environmental quality monitoring studies. Instrumental neutron activation analysis - INAA was applied to determine some nutrients and trace elements in invertebrate samples. Sampling by pitfall traps was carried out in riverine ecosystems from the urban area from the Piracicaba Municipality, State of Sao Paulo, Brazil. Invertebrate and reference material samples were irradiated in the nuclear research reactor IEA-R1, Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN. Fragments of a Ni-Cr alloy were irradiated for monitoring the thermal neutron flux. Hymenoptera order was considered the most representative according to the total number of sampled species (about 60%). Significant amounts of Ba, Br, Fe and Sc were found in invertebrates of the order Opiliones. Potassium, rubidium and zinc were highly accumulated in species from Blattodea order, indicating a consistent pattern of accumulation for this invertebrate order. Taking into account the abundance of Hymenoptera order, the chemical composition of its species was significant different at the 95% confidence level for Br and Na in the sampled locals. (author)

  12. Chemical elements in invertebrate orders for environmental quality studies

    International Nuclear Information System (INIS)

    Among the biomonitors of environmental quality, there is a lack of studies on using invertebrates to evaluate quantitatively chemical elements in ecosystems. This group of animals is quite numerous, widely distributed and adaptable to the most diverse environmental conditions. These features are very useful for the environmental quality assessment, as well as the several occurring insect-plant interactions performing essential functions in ecosystems. The objective of this work is to study the variability of chemical composition of invertebrate orders for using in environmental quality monitoring studies. Instrumental neutron activation analysis - INAA was applied to determine some nutrients and trace elements in invertebrate samples. Sampling by pitfall traps was carried out in riverine ecosystems from the urban area from the Piracicaba Municipality, State of Sao Paulo, Brazil. Invertebrate and reference material samples were irradiated in the nuclear research reactor IEA-R1, Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN. Fragments of a Ni-Cr alloy were irradiated for monitoring the thermal neutron flux. Hymenoptera order was considered the most representative according to the total number of sampled species (about 60%). Significant amounts of Ba, Br, Fe and Sc were found in invertebrates of the order Opiliones. Potassium, rubidium and zinc were highly accumulated in species from Blattodea order, indicating a consistent pattern of accumulation for this invertebrate order. Taking into account the abundance of Hymenoptera order, the chemical composition of its species was significant different at the 95% confidence level for Br and Na in the sampled locals. (author)

  13. Gas Metallicities in the Extended Disks of NGC 1512 and NGC 3621. Chemical Signatures of Metal Mixing or Enriched Gas Accretion?

    CERN Document Server

    Bresolin, Fabio; Ryan-Weber, Emma

    2012-01-01

    (Abridged) We have obtained spectra of 135 HII regions located in the inner and extended disks of the spiral galaxies NGC 1512 and NGC 3621, spanning the range of galactocentric distances 0.2-2 x R25 (from 2-3 kpc to 18-25 kpc). We find that the excitation properties of nebulae in the outer (R>R25) disks are similar to those of the inner disks, but on average younger HII regions tend to be selected in the bright inner disks. Reddening by dust is not negligible in the outer disks, and subject to significant large-scale spatial variations. For both galaxies the radial abundance gradient flattens to a constant value outside of the isophotal radius. The outer disk O/H abundance ratio is highly homogeneous, with a scatter of only ~0.06 dex. Based on the excitation and chemical (N/O ratio) analysis we find no compelling evidence for variations in the upper initial mass function of the ionizing clusters of extended disks. The O/H abundance in the outer disks of the target galaxies corresponds to 35% of the solar val...

  14. Science of Signatures Workshop on Secondary Ion Mass Spectrometry (SIMS) Applications July 24, 2012

    Energy Technology Data Exchange (ETDEWEB)

    Hickmott, Donald D [Los Alamos National Laboratory; Riciputi, Lee D [Los Alamos National Laboratory

    2012-07-23

    The science of signatures focus areas are: (1) Radiological and Nuclear; (2) Chemical and Materials (including explosives); (3) Biological - Signatures of Disease and Health; (4) Energy; (5) Climate; and (6) Space.

  15. Signature of a Collaboration Agreement between The Andrzej Soltan Institute for Nuclear Studies (IPJ) and CERN, by Prof. Grzegorz Wrochna, Director and CERN Director-General, concerning Collaboration in the LHC upgrade.

    CERN Multimedia

    Maximilien Brice

    2011-01-01

    Signature of a Collaboration Agreement between The Andrzej Soltan Institute for Nuclear Studies (IPJ) and CERN, by Prof. Grzegorz Wrochna, Director and CERN Director-General, concerning Collaboration in the LHC upgrade.

  16. Support to DHS Chemical Detection Field Testing and Countermeasures Studies: Report to Sponsors

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Michael; Black, Douglas; Delp, William

    2011-09-01

    This document reports on work that Lawrence Berkeley National Laboratory performed to support the Department of Homeland Security's testing of ARFCAM and LACIS systems. In the sections that follow, LBNL lists the scope of work, field analyses conducted, and preliminary results. LBNL developed a model of the Port Gaston building at the Nevada Test Site and calibrated it using data from field experiments, both blower door and tracer gas tests. Model development and comparison to data show very good agreement. The model was developed to (1) support the interpretation of data from field trials performed by Signature Science LLC, (2) support the placement of sampler equipment, and (3) predict if meteorological differences between the Wet-Run/Dry-Run and the Hot-Run might adversely affect the development of the Hot Run Test Plan. LBNL reported its findings on each task to the experiment team at scheduled planning meetings. In the end, we note that the model was used limitedly because the data from the Wet-Run/Dry Run were if such high quality. Lastly, LBNL conducted a research experiment at the end of the Wet-Run/Dry-Run to study if, and to what degree, specific TICs sorb and desorb on indoor surfaces. We found that several of the TICs either sorb onto surfaces or are lost through chemical reactions. These findings may have important implications on determining sheltering-in-place concepts of operation.

  17. NATO Advanced Study Institute on Advances in Chemical Reaction Dynamics

    CERN Document Server

    Capellos, Christos

    1986-01-01

    This book contains the formal lectures and contributed papers presented at the NATO Advanced Study Institute on. the Advances in Chemical Reaction Dynamics. The meeting convened at the city of Iraklion, Crete, Greece on 25 August 1985 and continued to 7 September 1985. The material presented describes the fundamental and recent advances in experimental and theoretical aspects of, reaction dynamics. A large section is devoted to electronically excited states, ionic species, and free radicals, relevant to chemical sys­ tems. In addition recent advances in gas phase polymerization, formation of clusters, and energy release processes in energetic materials were presented. Selected papers deal with topics such as the dynamics of electric field effects in low polar solutions, high electric field perturbations and relaxation of dipole equilibria, correlation in picosecond/laser pulse scattering, and applications to fast reaction dynamics. Picosecond transient Raman spectroscopy which has been used for the elucidati...

  18. Diacritical Seismic Signatures for Complex Geological Structures: Case Studies from Shushan Basin (Egypt and Arkoma Basin (USA

    Directory of Open Access Journals (Sweden)

    Mohamed I. Abdel-Fattah

    2014-01-01

    Full Text Available Seismic reflection techniques show an imperative role in imaging complex geological structures and are becoming more acceptable as data interpreting tools in 2D/3D view. These subsurface geological structures provide complex seismic signature due to their geometrical behavior. Consequently, it is extremely difficult to interpret these seismic sections in terms of subsurface configuration. The main goal of this paper is to introduce seismic attributes as a powerful tool to interpret complex geological structures in different geological settings. In order to image these complex geological features, multiple seismic attributes such as coherence and curvature have been applied to the seismic data generated over the Shushan Basin (Egypt and Arkoma Basin (USA. Each type of geological structure event usually generates a unique seismic “signature” that we can recognize and identify by using these seismic attributes. In Shushan Basin (Egypt, they provide a framework and constraint during the interpretation and can help prevent mistakes during a 3D structural modeling. In Arkoma Basin (USA, the seismic attributes results provide useful information for broader analyses of the complex structural relations in the region where the Ouachita orogenic belt intersects with the southern Oklahoma aulacogen. Finally, complex geological structures provide dramatically diacritical seismic signatures that can be easily interpreted by collaborating conventional seismic interpretation techniques with multiple seismic attributes.

  19. A Preliminary Study on Legal Validity of Electronic Signatures and Electronic Signatures Evidence%关于电子签名法律效力及作为证据的初步探析

    Institute of Scientific and Technical Information of China (English)

    陶阳

    2015-01-01

    Electronic signature has been widel and frequently used nowadays. However, as for the va-lidity of electronic contracts and electronic signatures in legal proceedings, together with the issue of how to use electronic signature evidence, the relative regulations are not clear. Based on the basic theo-ry of electronic signatures and the law of evidence, analyzes the effectiveness of China' s electronic sig-nature and the requirements of the form of electronic evidence. Finally, in judicial practice, through e-lectronic signature and other documents we can form a complete chain of evidence, improve the chances of adoption of the judiciary, and eventually safeguard people' s legitimate rights and interests.%21世纪,随着电子化的繁荣发展,电子签名的适用也越来越频繁,而在诉讼中如何确认电子合同及电子签名的效力,以及作为证据使用时需要注意的事项,还比较模糊. 本文力图从电子签名和证据法的基本理论入手,分析中国电子签名的效力及电子证据形式的要求. 最后在司法实践中,通过电子签名与其他文件相印证的方式使得形成一个完整的证据链,来提高司法机关采纳的几率,以便在产生纠纷时,维护好自己的合法权益.

  20. Thermogravimetric study of chemical compatibility of graphite with metal oxides

    International Nuclear Information System (INIS)

    Graphite and graphite mixtures with metal oxides are studied in conditions of nonisothermal heating to 1000 deg C using the methods of thermodynamic and gravimetric analyses. Chemical compatibility of graphite with Al2O3, CaO, SiO2, MgO, Fe2O3, TiO2, Na2O, K2O in the compositions considered is established. A decrease in the sample mass observed on the gravimetric curves in the presence of admixtures does not exceed the same value in pure graphite samples in specified conditions

  1. Studies on the Chemical Constituents and Bioactivities of Tripterygium Wilfordii

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Tripterygium wilfordii Hook (TW) is a medicinal plant distributed widely in southern china. This plant was recently found to possess anti-inflammatory, antitumor and immunosuppressive activities. Some preparation of the plant root has been used for the treatment of rheumatoid arthritis, systemic acne rosacea, nephritis and some skin diseases. Chemical studies on this plant and its preparation have shown they contain a large number of sesquiterpenoid, diterpenoids, triterpenoids and alkaloids in which some diterpene triepoxy lactones such as triptolide and triptonide etc are considered as mainly active compounds.

  2. Studies on the Chemical Constituents and Bioactivities of Tripterygium Wilfordii

    Institute of Scientific and Technical Information of China (English)

    LI; YuanChao

    2001-01-01

    Tripterygium wilfordii Hook (TW) is a medicinal plant distributed widely in southern china. This plant was recently found to possess anti-inflammatory, antitumor and immunosuppressive activities. Some preparation of the plant root has been used for the treatment of rheumatoid arthritis, systemic acne rosacea, nephritis and some skin diseases. Chemical studies on this plant and its preparation have shown they contain a large number of sesquiterpenoid, diterpenoids, triterpenoids and alkaloids in which some diterpene triepoxy lactones such as triptolide and triptonide etc are considered as mainly active compounds.  ……

  3. Phylogenomic Analyses and Comparative Studies on Genomes of the Bifidobacteriales: Identification of Molecular Signatures Specific for the Order Bifidobacteriales and Its Different Subclades

    Science.gov (United States)

    Zhang, Grace; Gao, Beile; Adeolu, Mobolaji; Khadka, Bijendra; Gupta, Radhey S.

    2016-01-01

    The order Bifidobacteriales comprises a diverse variety of species found in the gastrointestinal tract of humans and other animals, some of which are opportunistic pathogens, whereas a number of others exhibit health-promoting effects. However, currently very few biochemical or molecular characteristics are known which are specific for the order Bifidobacteriales, or specific clades within this order, which distinguish them from other bacteria. This study reports the results of detailed comparative genomic and phylogenetic studies on 62 genome-sequenced species/strains from the order Bifidobacteriales. In a robust phylogenetic tree for the Bifidobacteriales constructed based on 614 core proteins, a number of well-resolved clades were observed including a clade separating the Scarodvia-related genera (Scardovia clade) from the genera Bifidobacterium and Gardnerella, as well as a number of previously reported clusters of Bifidobacterium spp. In parallel, our comparative analyses of protein sequences from the Bifidobacteriales genomes have identified numerous molecular markers that are specific for this group of bacteria. Of these markers, 32 conserved signature indels (CSIs) in widely distributed proteins and 10 signature proteins are distinctive characteristics of all sequenced Bifidobacteriales species and provide novel and highly specific means for distinguishing these bacteria. In addition, multiple other molecular signatures are specific for the following clades of Bifidobacteriales: (i) 5 CSIs specific for a clade comprising of the Scardovia-related genera; (ii) 3 CSIs and 2 CSPs specific for a clade consisting of the Bifidobacterium and Gardnerella spp.; (iii) multiple other signatures demarcating a number of clusters of the B. asteroides-and B. longum- related species. The described molecular markers provide novel and reliable means for distinguishing the Bifidobacteriales and a number of their clades in molecular terms and for the classification of these

  4. Chemical and isotopic signature for mapping zones of sea water intrusion and residual saline pockets In coastal aquifers of the Egyptian Nile Delta

    International Nuclear Information System (INIS)

    The present study deals with the groundwater (Pleistocene aquifer) and surface water (drainage, lakes and sea water) in the northern sector of the Nile Delta (middle and east). This has been conducted to investigate the interaction between different water bodies in this important .area and to define the potential sources of salinity and pattern of variation. The stable environmental isotopes (Oxygen-18 and Deuterium) combined with .the hydrochemical. parameters have been used in the study. This leads to delineate the zones of active or retarded recharge rate and those which have been invaded by sea water due to over abstraction or affected by ancient residual saline pockets. These zones have been de marked on a map and interrelated with lithological and structural elements that characterize the area. Information have been developed on the recharge/discharge components and their contribution to water types, hydrochemical facies and salinity evolution; characterization have been made in this respect, for groundwater in middle delta and eastern delta and they are compared

  5. Matrix isolation as a tool for studying interstellar chemical reactions

    Science.gov (United States)

    Ball, David W.; Ortman, Bryan J.; Hauge, Robert H.; Margrave, John L.

    1989-01-01

    Since the identification of the OH radical as an interstellar species, over 50 molecular species were identified as interstellar denizens. While identification of new species appears straightforward, an explanation for their mechanisms of formation is not. Most astronomers concede that large bodies like interstellar dust grains are necessary for adsorption of molecules and their energies of reactions, but many of the mechanistic steps are unknown and speculative. It is proposed that data from matrix isolation experiments involving the reactions of refractory materials (especially C, Si, and Fe atoms and clusters) with small molecules (mainly H2, H2O, CO, CO2) are particularly applicable to explaining mechanistic details of likely interstellar chemical reactions. In many cases, matrix isolation techniques are the sole method of studying such reactions; also in many cases, complexations and bond rearrangements yield molecules never before observed. The study of these reactions thus provides a logical basis for the mechanisms of interstellar reactions. A list of reactions is presented that would simulate interstellar chemical reactions. These reactions were studied using FTIR-matrix isolation techniques.

  6. Modelling the X-ray polarimetric signatures of complex geometry: the case study of the "changing look" AGN NGC 1365

    CERN Document Server

    Marin, Frederic; Goosmann, Rene W; Dovciak, Michal; Muleri, Fabio; Grosso, Nicolas; Karas, Vladimir

    2013-01-01

    "Changing look" Active Galactic Nuclei (AGN) are a subset of Seyfert galaxies characterized by rapid transitions between Compton-thin and Compton-thick regimes. In their Compton-thin state, the central engine is less obscured, hence spectroscopy or timing observations can probe their innermost structures. However, it is not clear if the observed emission features and the Compton hump are associated with relativistic reflection onto the accretion disc, or complex absorption by distant, absorbing gas clouds passing by the observer's line-of-sight. Here, we investigate these two scenarios under the scope of X-ray polarimetry, providing the first polarisation predictions for an archetypal "changing look" AGN: NGC 1365. We explore the resulting polarisation emerging from lamp-post emission and scattering off an accretion disc in the immediate vicinity of a supermassive black hole. The computed polarisation signatures are compared to the results of an absorption-dominated model, where high column density gas partia...

  7. Machine Fault Signature Analysis

    Directory of Open Access Journals (Sweden)

    K. B. Mulchandani

    2008-03-01

    Full Text Available The objective of this paper is to present recent developments in the field of machine fault signature analysis with particular regard to vibration analysis. The different types of faults that can be identified from the vibration signature analysis are, for example, gear fault, rolling contact bearing fault, journal bearing fault, flexible coupling faults, and electrical machine fault. It is not the intention of the authors to attempt to provide a detailed coverage of all the faults while detailed consideration is given to the subject of the rolling element bearing fault signature analysis.

  8. Study of vacancy elimination in chemical diffusion and electromigration

    International Nuclear Information System (INIS)

    We have made an attempt to know the vacancy elimination mechanisms in diffusion phenomena where important non conservative vacancy fluxes are induced. Firstly, we have studied the validity of the phenomenological equations used to describe the diffusion and the associated Kirkendall effect in Gold-Silver System. We found a discrepancy between the results of theory and experiences, due to the presence of macroscopic cavities in the couples. We have shown that the physical description of the phenomenon remained correct under pressure but that the chemical diffusion could give rise to a 'lateral Kirkendall effect'. Secondly, we have made some Electron Microscopic observation in Au-Ag chemical diffusion zones and in pure metals were both an electric field and a temperature gradient where applied: we observed cavities and studied mainly the conditions for their formation. We measured super-saturations and found them to be very small (≅ 10-2). We conclude the observed cavities were due to a precipitation of gases instead of vacancies. When they are big enough (≅ 1000 A), these bubbles can act as nuclei for the cavities currently observed by optical microscopy. (author)

  9. Chemical reaction and dust formation studies in laboratory hydrocarbon plasmas.

    Science.gov (United States)

    Hippler, Rainer; Majumdar, Abhijit; Thejaswini, H. C.

    Plasma chemical reaction studies with relevance to, e.g., Titan's atmosphere have been per-formed in various laboratory plasmas [1,2]. Chemical reactions in a dielectric barrier discharge at medium pressure of 250-300 mbar have been studied in CH4 /N2 and CH4 /Ar gas mixtures by means of mass spectrometry. The main reaction scheme is production of H2 by fragmenta-tion of CH4 , but also production of larger hydrocarbons like Cn Hm with n up to 10 including formation of different functional CN groups is observed. [1] A. Majumdar and R. Hippler, Development of dielectric barrier discharge plasma processing apparatus for mass spectrometry and thin film deposition, Rev. Sci. Instrum. 78, 075103 (2007) [2] H.T. Do, G. Thieme, M. Frühlich, H. Kersten, and R. Hippler, Ion Molecule and Dust Particle Formation in Ar/CH4 , Ar/C2 H2 and Ar/C3 H6 Radio-frequency Plasmas, Contrib. Plasma Phys. 45, No. 5-6, 378-384 (2005)

  10. Study of commercial chemical additives for cementation of radioactive waste

    International Nuclear Information System (INIS)

    In this research it has been studied the effects of chemical additives (admixtures) in the cementation process of radioactive wastes, which are used to improve the properties of waste cementation process, both of the paste and of the solidified product. However there are a large variety of these materials that are frequently changed or taken out of the market, then it is essential to know the commercially available materials and their effects. The tests were carried out with a solution simulating the evaporator concentrate waste coming from PWR nuclear reactors. It was cemented using two formulations, A and B, incorporating higher or lower amount of waste, respectively. It was added chemical admixtures from two manufacturers (S and H), which were: accelerators, set retarders and superplasticizers. The experiments were organized by a factorial design 23. The measured parameters were the viscosity, the setting time, the paste and product density and the compressive strength. In this study we performed comparative analyzes of the results of compressive strength at age of 28 and 90 days and between the densities of the samples at the same ages. The compressive strength test at age of 28 days is considered a parameter essential issues related to security handling, transport and storage of cemented waste product. The results showed that the addition of accelerators improved the compressive strength of the cemented product, but presented lower values density products. (authors)

  11. Studying chemical vapor deposition processes with theoretical chemistry

    OpenAIRE

    Pedersen, Henrik; Elliott, Simon D.

    2014-01-01

    In a chemical vapor deposition (CVD) process, a thin film of some material is deposited onto a surface via the chemical reactions of gaseous molecules that contain the atoms needed for the film material. These chemical reactions take place on the surface and in many cases also in the gas phase. To fully understand the chemistry in the process and thereby also have the best starting point for optimizing the process, theoretical chemical modeling is an invaluable tool for providing atomic-scale...

  12. Close encounters of black holes, stars, and gas in galactic nuclei: A study of the observational signatures

    Science.gov (United States)

    Bogdanovic, Tamara

    We have investigated two different physical scenarios in which massive black holes interact with stars or gas. In the first scenario we have modeled the time-variable profiles of the H[alpha] emission line from the non-axisymmetric disk and debris tail created in the tidal disruption of a solar-type star by a 10 6 [Special characters omitted.] black hole. Two tidal disruption event simulations were carried out using a three dimensional relativistic smoothed- particle hydrodynamic (SPH) code, to describe the early evolution of the debris during the first fifty to ninety days. We have calculated the physical conditions and radiative processes in the debris using the photoionization code Cloudy . We model the emission line profiles in the period immediately after the accretion rate onto the black hole became significant. We find that the line profiles at these very early stages of the evolution of the postdisruption debris do not resemble the double peaked profiles expected from a rotating disk since the debris has not yet settled into such a stable structure. As a result of the uneven distribution of the debris and the existence of a "tidal tail" (the stream of returning debris), the line profiles depend sensitively on the orientation of the tail relative to the line of sight. Moreover, the predicted line profiles vary on fairly short time scales (of order hours to days). Given the accretion rate onto the black hole we also model the H[alpha] light curve from the debris and the evolution of the H[alpha] line profiles in time. In the second scenario we model the electromagnetic emission signatures of massive black hole binaries (MBHBs) with an associated gas component. The method comprises numerical simulations of relativistic binaries and gas coupled with calculations of the physical properties of the emitting gas. We calculate the accretion powered UV/X-ray and the H[alpha] light curves and H[alpha] emission line profiles. The binary plus gas simulations are carried

  13. Chemical dispersibility study of heavy bunker fuel oil

    Energy Technology Data Exchange (ETDEWEB)

    Fiocco, R. J. [R. J. Fiocco Associates, Summit, NJ (United States); Daling, P. S. [SINTEF, Trondheim, (Norway); DeMarco, G.; Lessard, R. R. [Exxon Research and Engineering Company, Florham Park, NJ (United States); Canevari, G. P. [G. P. Canevari and Associates, Cranford, NJ (United States)

    1999-08-01

    Chemical dispersibility of heavy bunker fuel oil, which historically has been characterized as not dispersible, was studied, using the well-known SINTEF methodology for evaluating the dispersibility of fresh and weathered oils. Several heavy fuel oils, specifically IFO-380 fuel oils, were involved in the study. Corexit 9500, which has been shown to be effective for viscous and weathered oils, was used as the dispersant. Results indicated that in many cases heavy fuel oils are dispersible, and that viscosity and dispersant dosage are particularly important factors. As a general rule, more viscous and weathered oils were found to require longer time for the dispersion process to occur. The standard SINTEF laboratory effectiveness test, particularly the 60-minute extended -time MNS tests, have been found to be very useful in characterizing heavy fuel oil dispersibility. 17 refs., 5 tabs., 1 fig.

  14. Chemical dispersibility study of heavy bunker fuel oil

    Energy Technology Data Exchange (ETDEWEB)

    Fiocco, R. J. [R. J. Fiocco Associates, Summit, NJ (United States); Daling, P. S. [SINTEF, Trondheim, (Norway); DeMarco, G.; Lessard, R. R. [Exxon Research and Engineering Company, Florham Park, NJ (United States); Canevari, G. P. [G. P. Canevari and Associates, Cranford, NJ (United States)

    1999-07-01

    Chemical dispersibility of heavy bunker fuel oil, which historically has been characterized as not dispersible, was studied, using the well-known SINTEF methodology for evaluating the dispersibility of fresh and weathered oils. Several heavy fuel oils, specifically IFO-380 fuel oils, were involved in the study. Corexit 9500, which has been shown to be effective for viscous and weathered oils, was used as the dispersant. Results indicated that in many cases heavy fuel oils are dispersible, and that viscosity and dispersant dosage are particularly important factors. As a general rule, more viscous and weathered oils were found to require longer time for the dispersion process to occur. The standard SINTEF laboratory effectiveness test, particularly the 60-minute extended -time MNS tests, have been found to be very useful in characterizing heavy fuel oil dispersibility. 17 refs., 5 tabs., 1 fig.

  15. Chemical dispersibility study of heavy bunker fuel oil

    Energy Technology Data Exchange (ETDEWEB)

    Fiocco, R. J. (R. J. Fiocco Associates, Summit, NJ (United States)); Daling, P. S. (SINTEF, Trondheim, (Norway)); DeMarco, G.; Lessard, R. R. (Exxon Research and Engineering Company, Florham Park, NJ (United States)); Canevari, G. P. (G. P. Canevari and Associates, Cranford, NJ (United States))

    1999-01-01

    Chemical dispersibility of heavy bunker fuel oil, which historically has been characterized as not dispersible, was studied, using the well-known SINTEF methodology for evaluating the dispersibility of fresh and weathered oils. Several heavy fuel oils, specifically IFO-380 fuel oils, were involved in the study. Corexit 9500, which has been shown to be effective for viscous and weathered oils, was used as the dispersant. Results indicated that in many cases heavy fuel oils are dispersible, and that viscosity and dispersant dosage are particularly important factors. As a general rule, more viscous and weathered oils were found to require longer time for the dispersion process to occur. The standard SINTEF laboratory effectiveness test, particularly the 60-minute extended -time MNS tests, have been found to be very useful in characterizing heavy fuel oil dispersibility. 17 refs., 5 tabs., 1 fig.

  16. Are there molecular signatures?

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, W.P.

    1995-10-01

    This report describes molecular signatures and mutational spectrum analysis. The mutation spectrum is defined as the type and location of DNA base change. There are currently about five well documented cases. Mutations and radon-associated tumors are discussed.

  17. Advanced Missile Signature Center

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Missile Signature Center (AMSC) is a national facility supporting the Missile Defense Agency (MDA) and other DoD programs and customers with analysis,...

  18. THE ELECTRONIC SIGNATURE

    OpenAIRE

    Voiculescu Madalina Irena; Gramada Dragu Argentina

    2009-01-01

    Article refers to significance and the digital signature in electronic commerce. Internet and electronic commerce open up many new opportunities for the consumer, yet, the security (or perceived lack of security) of exchanging personal and financial data

  19. Meteor signature interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Canavan, G.H.

    1997-01-01

    Meteor signatures contain information about the constituents of space debris and present potential false alarms to early warnings systems. Better models could both extract the maximum scientific information possible and reduce their danger. Accurate predictions can be produced by models of modest complexity, which can be inverted to predict the sizes, compositions, and trajectories of object from their signatures for most objects of interest and concern.

  20. Stateless Transitive Signature Schemes

    Institute of Scientific and Technical Information of China (English)

    MA Chun-guang; CAI Man-chun; YANG Yi-xian

    2004-01-01

    A new practical method is introduced to transform the stateful transitive signature scheme to stateless one without the loss of security. According to the approach, two concrete stateless transitive signature schemes based on Factoring and RSA are presented respectively. Under the assumption of the hardness of factoring and one-more- RSA-inversion problem, both two schemes are secure under the adaptive chosen-message attacks in random oracle model.

  1. Machine Fault Signature Analysis

    OpenAIRE

    Mulchandani, K. B.; A.K. Wadhwani; Pratesh Jayaswal

    2008-01-01

    The objective of this paper is to present recent developments in the field of machine fault signature analysis with particular regard to vibration analysis. The different types of faults that can be identified from the vibration signature analysis are, for example, gear fault, rolling contact bearing fault, journal bearing fault, flexible coupling faults, and electrical machine fault. It is not the intention of the authors to attempt to provide a detailed coverage of all the faults while deta...

  2. Ecosystem engineers and geomorphological signatures in landscapes

    Science.gov (United States)

    Jones, Clive G.

    2012-07-01

    Biogeomorphologists study the roles of biota in landscape formation and decay. Ecologists interested in ecosystem engineering study environmental change caused by biota and the consequences for the engineer, other organisms, and ecological processes. The interface is geomorphological change, an interface both are aware of but study somewhat independently and differently. Interaction and integration among the two fields is the goal of this special issue. Here I take an ecological perspective of geomorphological change caused by ecosystem engineers in patches within landscapes that I hope can help facilitate this goal. I ask the following general questions: When will an ecosystem engineering species create a geomorphological signature in a landscape? What, in qualitative terms, is such a signature? How can the signature be estimated and how long will it last? What engineer attributes and ecological factors will determine signature change? What creates complications? How do the answers inform whether or not life leaves a geomorphological signature? To attempt answers, I develop a provisional, general theory of ecosystem engineering signatures that draws on and integrates a geomorphological foundation of balance between formation and decay; landscape patch dynamics; a general framework for ecosystem engineering; and empirical studies. I treat a landscape engineering signature as the balance of rates of formation (F) and rates of decay (D) across patches whose ratio value (F/D) can be transformed (> 1), intermediate (1) or untransformed (leaves a geomorphological signature, using this to contrast my approach with biogeomorphology, and asking what a hypothetical analysis of signature patterns across many engineer species/landscape combinations might imply for the interface of ecology and biogeomorphology.

  3. Maximizing biomarker discovery by minimizing gene signatures

    Directory of Open Access Journals (Sweden)

    Chang Chang

    2011-12-01

    Full Text Available Abstract Background The use of gene signatures can potentially be of considerable value in the field of clinical diagnosis. However, gene signatures defined with different methods can be quite various even when applied the same disease and the same endpoint. Previous studies have shown that the correct selection of subsets of genes from microarray data is key for the accurate classification of disease phenotypes, and a number of methods have been proposed for the purpose. However, these methods refine the subsets by only considering each single feature, and they do not confirm the association between the genes identified in each gene signature and the phenotype of the disease. We proposed an innovative new method termed Minimize Feature's Size (MFS based on multiple level similarity analyses and association between the genes and disease for breast cancer endpoints by comparing classifier models generated from the second phase of MicroArray Quality Control (MAQC-II, trying to develop effective meta-analysis strategies to transform the MAQC-II signatures into a robust and reliable set of biomarker for clinical applications. Results We analyzed the similarity of the multiple gene signatures in an endpoint and between the two endpoints of breast cancer at probe and gene levels, the results indicate that disease-related genes can be preferably selected as the components of gene signature, and that the gene signatures for the two endpoints could be interchangeable. The minimized signatures were built at probe level by using MFS for each endpoint. By applying the approach, we generated a much smaller set of gene signature with the similar predictive power compared with those gene signatures from MAQC-II. Conclusions Our results indicate that gene signatures of both large and small sizes could perform equally well in clinical applications. Besides, consistency and biological significances can be detected among different gene signatures, reflecting the

  4. A lipidomics study reveals hepatic lipid signatures associating with deficiency of the LDL receptor in a rat model.

    Science.gov (United States)

    Wang, Hong Yu; Quan, Chao; Hu, Chunxiu; Xie, Bingxian; Du, Yinan; Chen, Liang; Yang, Wei; Yang, Liu; Chen, Qiaoli; Shen, Bin; Hu, Bian; Zheng, Zhihong; Zhu, Haibo; Huang, Xingxu; Xu, Guowang; Chen, Shuai

    2016-01-01

    The low-density lipoprotein receptor (LDLR) plays a critical role in the liver for the clearance of plasma low-density lipoprotein (LDL). Its deficiency causes hypercholesterolemia in many models. To facilitate the usage of rats as animal models for the discovery of cholesterol-lowering drugs, we took a genetic approach to delete the LDLR in rats aiming to increase plasma LDL cholesterol (LDL-C). An LDLR knockout rat was generated via zinc-finger nuclease technology, which harbors a 19-basepair deletion in the seventh exon of the ldlr gene. As expected, deletion of the LDLR elevated total cholesterol and total triglyceride in the plasma, and caused a tenfold increase of plasma LDL-C and a fourfold increase of plasma very low-density lipoprotein (VLDL-C). A lipidomics analysis revealed that deletion of the LDLR affected hepatic lipid metabolism, particularly lysophosphatidylcholines, free fatty acids and sphingolipids in the liver. Cholesterol ester (CE) 20:4 also displayed a significant increase in the LDLR knockout rats. Taken together, the LDLR knockout rat offers a new model of hypercholesterolemia, and the lipidomics analysis reveals hepatic lipid signatures associating with deficiency of the LDL receptor. PMID:27378433

  5. Study on microwave assisted process in chemical extraction

    International Nuclear Information System (INIS)

    The microwave assisted process is a revolutionary method of extraction that reduces the extraction time to as little as a few seconds, with up to a ten-fold decrease in the use of solvents. The target material is immersed in solvent that is transparent to microwaves, so only the target material is heated, and because of the microwaves tend to heat the inside of the material quickly, the target chemical are expelled in a few seconds. benefits from this process include significant reductions in the amount of energy required and substantial reductions in the cost and dispose of hazardous solvents. A thorough review has been displayed on: using the microwave in extraction, applications of microwave in industry, process flow diagram, mechanism of the process and comparison between microwave process and other extraction techniques (soxhlet, steam distillation and supercritical fluid). This review attempts to summarize the studies about microwave assisted process as a very promising technique. (Author)

  6. Study of physical chemical characteristics of a shungite

    OpenAIRE

    Maira Kazankapova; A. Bekzhanova; Sergey Efremov; Mikhail Nauryzbayev

    2012-01-01

    The physico-chemical characteristics of shungite from the field of Kazakhstan ("Bakyrchik") and Russia ("Zazhegino") was studied by elemental analysis, IR- spectroscopy and electron microscopy. The content of carbon in the schungite field "Zazhegino" is 28,0-31,0 %,  in the field "Bakyrchik" - 15,0-19,0 %, in schungite concentrate  "Bakyrchik" is 40,0 ± 2,0 %.  IR-spectroscopic analysis have been shown that carboxyl groups appear in addition to the concentrate of polycyclic hydrocarbons conta...

  7. Chemical treatment of zinc surface and its corrosion inhibition studies

    Indian Academy of Sciences (India)

    S K Rajappa; T V Venkatesha; B M Praveen

    2008-02-01

    The surface treatment of zinc and its corrosion inhibition was studied using a product (BTSC) formed in the reaction between benzaldehyde and thiosemicarbozide. The corrosion behaviour of chemically treated zinc surface was investigated in aqueous chloride–sulphate medium using galvanostatic polarization technique. Zinc samples treated in BTSC solution exhibited good corrosion resistance. The measured electrochemical data indicated a basic modification of the cathode reaction during corrosion of treated zinc. The corrosion protection may be explained on the basis of adsorption and formation of BTSC film on zinc surface. The film was binding strongly to the metal surface through nitrogen and sulphur atoms of the product. The formation of film on the zinc surface was established by surface analysis techniques such as scanning electron microscopy (SEM–EDS) and Fourier transform infrared spectroscopy (FTIR).

  8. [Study of quantum-pharmacological chemical characteristics of quercetin].

    Science.gov (United States)

    Zahorodnyĭ, M I

    2007-01-01

    It was established in the previous studies that quercetin prevented the development and caused faster regression of ulcers, petechia and anabroses in rats, which were induced by diclofenac taking. In the group of patients taking diclofenac together with quercetin, the ulcers and dyspeptic events were less found. The application of quercetin normalizes the function and metabolism of cartilage tissue of rabbits with an experimental osteoarthrosis and in patients with osteoartrosis. Quantum-chemical properties of molecule quercetin were studied using the methods of molecular mechanics MM+ and ab initio 6-31G*, and also semiempirical method. The following indices were investigated: distance between atoms (A), the distribution of electronic density of only external valency electrons, distribution of electrostatic potential; common energy of the exertion of molecule (kkal/mmol); binding energy (kkal/mmol); electron energy (kkal/mmol); energy of nucleus-nucleus interaction (kkal/mmol); formation heat (kkal/mmol); atomic charge (eB); value of the dipole moment of molecule (D); localization and energy of highest occupied orbital (HOMO) and the lowest unoccupied (LUMO) molecular orbital (eB) of quercetin miolecule; the value of absolute rigidity of chemical structure of bioflavonoid. It was shown, that bioflavonoid quercetin belongs to mild reagents, has nucleophilic properties, can react with alkaline, unsaturated and aromatic compounds,. Polar substitutes in the quercetine molecule influence on the distribution of superficial valency electrons and localization of HOMO and LUMO. The energy value of quercetin LUMO enables us to refer quercetine to the reducing agent and it is illustrated by antioxidant properties of this medicine. PMID:18663944

  9. ALTERNATIVE AND ENHANCED CHEMICAL CLEANING: CORROSION STUDIES RESULTS: FY2010

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.

    2010-09-29

    Due to the need to close High Level Waste storage tanks, chemical cleaning methods are needed for the removal of sludge heel materials remaining at the completion of mechanical tank cleaning efforts. Oxalic acid is considered the preferred cleaning reagent for heel dissolution of iron-based sludge. However, the large quantity of chemical reagents added to the tank farm from oxalic acid based cleaning has significant downstream impacts. Optimization of the oxalic acid cleaning process can potentially reduce the downstream impacts from chemical cleaning. To optimize oxalic acid usage, a detailed understanding of the chemistry of oxalic acid based sludge dissolution is required. Additionally, other acidic systems may be required for specific waste components that have low solubility in oxalic acid, and as a means to reduce oxalic acid usage in general. Electrochemical corrosion studies were conducted with 1 wt. % oxalic acid at mineral acid concentrations above and below the optimal conditions for this oxalic acid concentration. Testing environments included pure reagents, pure iron and aluminum phases, and sludge simulants. Mineral acid concentrations greater than 0.2 M and temperatures greater than 50 C result in unacceptably high corrosion rates. Results showed that manageable corrosion rates of carbon steel can be achieved at dilute mineral acid concentrations (i.e. less than 0.2 M) and low temperatures based on the contact times involved. Therefore, it is recommended that future dissolution and corrosion testing be performed with a dilute mineral acid and a less concentrated oxalic acid (e.g., 0.5 wt.%) that still promotes optimal dissolution. This recommendation requires the processing of greater water volumes than those for the baseline process during heel dissolution, but allows for minimization of oxalic acid additions. The following conclusions can be drawn from the test results: (1) In both nitric and sulfuric acid based reagents, the low temperature and

  10. Study of medical isotope production facility stack emissions and noble gas isotopic signature using automatic gamma-spectra analysis platform

    Science.gov (United States)

    Zhang, Weihua; Hoffmann, Emmy; Ungar, Kurt; Dolinar, George; Miley, Harry; Mekarski, Pawel; Schrom, Brian; Hoffman, Ian; Lawrie, Ryan; Loosz, Tom

    2013-04-01

    The nuclear industry emissions of the four CTBT (Comprehensive Nuclear-Test-Ban Treaty) relevant radioxenon isotopes are unavoidably detected by the IMS along with possible treaty violations. Another civil source of radioxenon emissions which contributes to the global background is radiopharmaceutical production companies. To better understand the source terms of these background emissions, a joint project between HC, ANSTO, PNNL and CRL was formed to install real-time detection systems to support 135Xe, 133Xe, 131mXe and 133mXe measurements at the ANSTO and CRL 99Mo production facility stacks as well as the CANDU (CANada Deuterium Uranium) primary coolant monitoring system at CRL. At each site, high resolution gamma spectra were collected every 15 minutes using a HPGe detector to continuously monitor a bypass feed from the stack or CANDU primary coolant system as it passed through a sampling cell. HC also conducted atmospheric monitoring for radioxenon at approximately 200 km distant from CRL. A program was written to transfer each spectrum into a text file format suitable for the automatic gamma-spectra analysis platform and then email the file to a server. Once the email was received by the server, it was automatically analysed with the gamma-spectrum software UniSampo/Shaman to perform radionuclide identification and activity calculation for a large number of gamma-spectra in a short period of time (less than 10 seconds per spectrum). The results of nuclide activity together with other spectrum parameters were saved into the Linssi database. This database contains a large amount of radionuclide information which is a valuable resource for the analysis of radionuclide distribution within the noble gas fission product emissions. The results could be useful to identify the specific mechanisms of the activity release. The isotopic signatures of the various radioxenon species can be determined as a function of release time. Comparison of 133mXe and 133Xe activity

  11. A feasibility study on the expected seismic AVA signatures of deep fractured geothermal reservoirs in an intrusive basement

    International Nuclear Information System (INIS)

    The deep geothermal reservoirs in the Larderello-Travale field (southern Tuscany) are found in intensively fractured portions of intrusive/metamorphic rocks. Therefore, the geothermal exploration has been in search of possible fracture signatures that could be retrieved from the analysis of geophysical data. In the present work we assess the feasibility of finding seismic markers in the pre-stack domain which may pinpoint fractured levels. Thanks to the availability of data from boreholes that ENEL GreenPower drilled in the deep intrusive basement of this geothermal field, we derived the expected amplitude versus angle (AVA) responses of the vapour reservoirs found in some intensely, but very localized, fractured volumes within the massive rocks. The information we have available limit us to build 1D elastic and isotropic models only and thus anisotropy effects related to the presence of fractures cannot be properly modelled. We analysed the velocities and the density logs pertaining to three wells which reached five deep fractured zones in the basement. The AVA response of the fractured intervals is modelled downscaling the log data to seismic scale and comparing the analytical AVA response (computed with the Aki and Richards approximation) and the AVA extracted from a synthetic common mid point (calculated making use of a reflectivity algorithm). The results show that the amplitude of the reflections from the fractured level is characterized by negative values at vertical incidence and by decreasing absolute amplitudes with the increase of the source to receiver offset. This contrasts with many observations from hydrocarbon exploration in clastic reservoirs where gas-sand reflections often exhibit negative amplitudes at short offsets but increasing absolute amplitudes for increasing source to receiver offsets. Thereby, some common AVA attributes considered in silicoclastic lithologies would lead to erroneous fracture localization. For this reason we propose a

  12. Microbiological and physico-chemical studies on irradiated dewatered sludge

    International Nuclear Information System (INIS)

    Microbiological and physico-chemical studies on irradiated dewatered sludge. Microbiological and physico-chemical dewatered have been carried out and non-irradiated dewatered sludge of Jakarta city, collected during the rainy and dry season. Total bacterial counts of non-irradiated dewatered sludge with water content of around 20%, were found to be about 7x108 per g during the rainy season and 7x106 up to 1.3x108 per g during the dry season, while coliform fecal Streptococcus and Pseudomonas were found to be 1.6x104 to 1.0x107, 3x105, and 5x103 per g, respectively. No Salmonella, Shigella and Vibrio were detected in all of the samples observed. About 10% of the total number of coliforms were found to be Escherichia coli. A dose of 6 kGy could eliminate the coliform, E. Coli, fecal Streptococcus and Pseudomonas from all of the dewatered sludge observed. The nutrient value of the sludge was sufficient, i.e. total nitrogen content ranged between 1 and 4,42%, phosphorus between 1.55 and 2.36%, and potassium between 0,1 and 0,2% of dry matter. Heavy metal contents were found a little bit high to be applied as animal feed, but it is still acceptable for soil conditioner. Combining 3 months storage at ambient environment and irradiation dose of 2.5 kGy were found to work synergistically to eliminate coliforms and E. Coli from sludge. (author). 8 figs, 17 refs

  13. Oceanographic studies using dissolved gases as chemical tracers

    International Nuclear Information System (INIS)

    This article reviews the author's hitherto progress on marine geochemical studies using the concentration, radioactivity, and stable isotope ratio of dissolved gases as chemical tracers in the ocean. Shipboard gas chromatography was developed for the simultaneous measurement of major dissolved gases (O2, N2, Ar and ΣCO2). A Carpenter-modified titration method was introduced for the improvement of the accuracy of O2 data, which played an important role in discovering and monitoring temporal variations in deep convection systems in the Japan Sea, an ideal miniature of global oceans. Radiocarbon (14C) measurements together with precise ΣCO2 and δ13C data enabled the author to clarify the timescale of the abyssal circulation of the Japan Sea, the characteristics of bottom waters in the Philippine Sea, and the invasion rate of bomb 14C from the atmosphere to the western Pacific seawater. Minor dissolved gases, 222Rn and CH4 in seawater, were also analyzed using the originally designed shipboard measurement systems. The activity of 222Rn (in excess over the 226Ra-supported portion) in bottom seawaters was applied for the estimation of CO2 flux from a submarine volcano in Kagoshima Bay, and for the mapping of vertical eddy diffusivity just above the bottom over a wide area of the northwestern Pacific Ocean, where the distribution and characteristics of benthic boundary layers were also researched. Data on CH4 in deep seawaters were accumulated at and around hydrothermally active sites or cold seepage zones associated with plate boundaries, to discover new active vents and elucidate the chemical characteristics of emanating fluids from the seafloor. (author)

  14. STUDYING THE CHEMICAL COMPOSITION OF ALCOHOLIC EXTRACT SCHROTH RAPE

    Directory of Open Access Journals (Sweden)

    Елена Эдуардовна Чигиринец

    2014-09-01

    Full Text Available As the authors found that a promising material for a volatile atmospheric corrosion inhibitor is the use of waste generated in obtaining oil from rapeseed (family Brassicaceae, namely rapeseed meal, appropriate research was qualitative and quantitative determination of its basic compounds. Also found that the inhibition efficiency is extreme character with a maximum protective capacity for 2 hours. Why was it necessary to study changes in the composition of the extract in the evaporation process, and identification of compounds that do not take part in the formation of the film, that is remaining in the non-volatile sludge. The subject of this study is to extract 2-proрanol rapeseed cake extract . The purpose of work - a study of its component composition, namely, volatile and non-volatile compounds. The volatile chemical composition of the rapeseed cake extract involves glycosides, nucleosides, ketone, aldehyde, fatty acids, sterol and alkaloids. The most important compounds in rapeseed cake are: Guanosine , Sucrose , Xanthosine, 3',5'-Dimethoxyacetophenone Benzaldehyde, 4-hydroxy-3,5-dimethoxy, Acetic, Oleic, Linoleic and Palmitic acid and Sterols.

  15. Explosives Detection: Exploitation of the Physical Signatures

    Science.gov (United States)

    Atkinson, David

    2010-10-01

    Explosives based terrorism is an ongoing threat that is evolving with respect to implementation, configuration and materials used. There are a variety of devices designed to detect explosive devices, however, each technology has limitations and operational constraints. A full understanding of the signatures available for detection coupled with the array of detection choices can be used to develop a conceptual model of an explosives screening operation. Physics based sensors provide a robust approach to explosives detection, typically through the identification of anomalies, and are currently used for screening in airports around the world. The next generation of detectors for explosives detection will need to be more sensitive and selective, as well as integrate seamlessly with devices focused on chemical signatures. An appreciation for the details of the physical signature exploitation in cluttered environments with time, space, and privacy constraints is necessary for effective explosives screening of people, luggage, cargo, and vehicles.

  16. Actions for signature change

    CERN Document Server

    Embacher, F

    1995-01-01

    This is a contribution on the controversy about junction conditions for classical signature change. The central issue in this debate is whether the extrinsic curvature on slices near the hypersurface of signature change has to be continuous ({\\it weak} signature change) or to vanish ({\\it strong} signature change). Led by a Lagrangian point of view, we write down eight candidate action functionals S_1,...S_8 as possible generalizations of general relativity and investigate to what extent each of these defines a sensible variational problem, and which junction condition is implied. Four of the actions involve an integration over the total manifold. A particular subtlety arises from the precise definition of the Einstein-Hilbert Lagrangian density |g|^{1/2} R[g]. The other four actions are constructed as sums of integrals over singe-signature domains. The result is that {\\it both} types of junction conditions occur in different models, i.e. are based on different first principles, none of which can be claimed t...

  17. 相似度算法在手写签名质谱成像鉴定中的应用研究%Studies on verification of handwritten signatures by mass spectrometry imaging with the Similarity Algorithm

    Institute of Scientific and Technical Information of China (English)

    刘亚丽; 贾滨; 丁丽英; 吴佳; 陈焕文; 章文军

    2012-01-01

    质谱成像技术无需任何样品预处理,即可获取待测样品的分了信息和分布情况.本文采用表面解吸常压化学电离质谱(SDAPCI-MS)技术对手写签名样品进行检测,通过对所得的质谱特征峰信号进行成像处理,获取书写油墨分布的强度信息.实验结果表明真实签名和伪造签名因为笔压轻重不同而油墨分布位置不同,据此能够区分签名的真伪.应用相似度算法对手写签名的特征成像数据进行分析,在样品量较少的情况下,能够客观的比较真迹之间以及真迹和伪迹之间的相似程度,进而实现对真伪签名的准确鉴定.本方法操作简便,耗时较短,对手写笔迹的鉴定具有重要的借鉴意义.%Without any sample pretreatment, mass spectrometry imaging (MSI) can provide molecular information and the molecular distribution information on the sample. Handwritten signature samples were directly detected by surface desorption atmospheric pressure chemical ionization mass spectrometry (SDAPCI-MS). The mass spectra recorded by SDAPCI-MS were subjected to data processing. It is easy to distinguish the authentic signature and the forged signature by observing the strength of the corresponding mass spectrometry imaging of the handwritten signature. Considering the relative ink concentration feature, which is extracted from the data of the handwritten signature, as a feature of the signature, we provide useful data by processing the data gained from mass spectrometry imaging. The Similarity Algorithm is applied to the handwritten signature verification, and this method gives excellent results. The results demonstrate that this method is both simple and fast, and the method is a promising technique for the verification of handwritten signatures with few samples.

  18. Sustainability Indicators for Chemical Processes: III. Biodiesel Case Study

    Science.gov (United States)

    The chemical industry is one of the most important business sectors, not only economically, but also societally; as it allows humanity to attain higher standards and quality of life. Simultaneously, chemical products and processes can be the origin of potential human health and ...

  19. Chemical grouting – laboratory study of chemical grouts and geocomposites properties

    Czech Academy of Sciences Publication Activity Database

    Souček, Kamil; Staš, Lubomír; Ščučka, Jiří; Martinec, Petr

    Bombay : Indian Institute of Technology Bombay, 2008 - (Singh, D.), s. 3567-3574 [International Conference of IACMAG /12./. Goa - Panjim (IN), 01.10.2008-06.10.2008] R&D Projects: GA ČR(CZ) GA105/07/1533 Institutional research plan: CEZ:AV0Z30860518 Keywords : chemical grouts * grouting, geocomposite properties Subject RIV: DB - Geology ; Mineralogy

  20. Organic chemical degradation by remote study of the redox conditions

    Science.gov (United States)

    Fernandez, P. M.; Revil, A.; Binley, A. M.; Bloem, E.; French, H. K.

    2014-12-01

    Monitoring the natural (and enhanced) degradation of organic contaminants is essential for managing groundwater quality in many parts of the world. Contaminated sites often have limited access, hence non-intrusive methods for studying redox processes, which drive the degradation of organic compounds, are required. One example is the degradation of de-icing chemicals (glycols and organic salts) released to the soil near airport runways during winter. This issue has been broadly studied at Oslo airport, Gardermoen, Norway using intrusive and non-intrusive methods. Here, we report on laboratory experiments that aim to study the potential of using a self-potential, DCresistivity, and time-domain induced polarization for geochemical characterization of the degradation of Propylene Glycol (PG). PG is completely miscible in water, does not adsorb to soil particles and does not contribute to the electrical conductivity of the soil water. When the contaminant is in the unsaturated zone near the water table, the oxygen is quickly consumed and the gas exchange with the surface is insufficient to ensure aerobic degradation, which is faster than anaerobic degradation. Since biodegradation of PG is highly oxygen demanding, anaerobic pockets can exist causing iron and manganese reduction. It is hypothesised that nitrate would boost the degradation rate under such conditions. In our experiment, we study PG degradation in a sand tank. We provide the system with an electron highway to bridge zones with different redox potential. This geo-battery system is characterized by self-potential, resistivity and induced polarization anomalies. An example of preliminary results with self-potential at two different times of the experiment can be seen in the illustration. These will be supplemented with more direct information on the redox chemistry: in-situ water sampling, pH, redox potential and electrical conductivity measurements. In parallel, a series of batch experiments have been

  1. Carbon-13 natural abundance signatures of long-chain fatty acids to determinate sediment origin: A case study in northeast Austria

    Science.gov (United States)

    Mabit, Lionel; Gibbs, Max; Meusburger, Katrin; Toloza, Arsenio; Resch, Christian; Klik, Andreas; Swales, Andrew; Alewell, Christine

    2016-04-01

    - Several recently published information from scientific research have highlighted that compound-specific stable isotope (CSSI) signatures of fatty acids (FAs) based on the measurement of carbon-13 natural abundance signatures showed great promises to identify sediment origin. The authors have used this innovative isotopic approach to investigate the sources of sediment in a three hectares Austrian sub-watershed (i.e. Mistelbach). Through a previous study using the Cs-137 technique, Mabit et al. (Geoderma, 2009) reported a local maximum sedimentation rate reaching 20 to 50 t/ha/yr in the lowest part of this watershed. However, this study did not identify the sources. Subsequently, the deposited sediment at its outlet (i.e. the sediment mixture) and representative soil samples from the four main agricultural fields - expected to be the source soils - of the site were investigated. The bulk delta carbon-13 of the samples and two long-chain FAs (i.e. C22:0 and C24:0) allowed the best statistical discrimination. Using two different mixing models (i.e. IsoSource and CSSIAR v1.00) and the organic carbon content of the soil sources and sediment mixture, the contribution of each source has been established. Results suggested that the grassed waterway contributed to at least 50% of the sediment deposited at the watershed outlet. This study, that will require further validation, highlights that CSSI and Cs-137 techniques are complementary as fingerprints and tracers for establishing land sediment redistribution and could provide meaningful information for optimized decision-making by land managers.

  2. Chemical studies of single-walled carbon nanotubes

    CERN Document Server

    Xu, C

    2001-01-01

    WCl sub 6 has also been introduced into arc-vapourised SWNTs. Chapter 6 gives the details for all the experimental work of the thesis. of H sub 2 have also been studied. Chapter four describes the various processes used to purify arc-vapourised SWNTs on a laboratory scale. Two potentially scalable processes have also been studied. Both acid and gas oxidants have been used to purify SWNTs grown in the CVD method. The chemical resistance of CVD SWNTs (48 h of conc. HNO sub 3 treatment) has been shown for the first time. Various assembly behaviours of purified SWNTs, including loop and spiral structures, straight long bundles or somewhat aligned structures, are also described. Chapter five presents the filling of arc-vapourised SWNTs with LnX sub n (X = Cl, Br and I, n = 2 or 3) using the capallarity method at high temperature (570-910 deg C). The first example of a polycrystalline structure within SWNTs filled with a single material (SmCl sub 3) has been provided. Fullerenes within SWNTs in the SWNT samples ext...

  3. NATO Advanced Study Institute on Chemical Transport in Melasomatic Processes

    CERN Document Server

    1987-01-01

    As indicated on the title page, this book is an outgrowth of the NATO Advanced Study Institute (ASI) on Chemical Transport in Metasomatic Processes, which was held in Greece, June 3-16, 1985. The ASI consisted of five days of invited lectures, poster sessions, and discussion at the Club Poseidon near Loutraki, Corinthia, followed by a two-day field trip in Corinthia and Attica. The second week of the ASI consisted of an excursion aboard M/S Zeus, M/Y Dimitrios II, and the M/S Irini to four of the Cycladic Islands to visit, study, and sample outstanding exposures of metasomatic activity on Syros, Siphnos, Seriphos, and Naxos. Nine­ teen invited lectures and 10 session chairmen/discussion leaders participated in the ASI, which was attended by a total of 92 professional scientists and graduate stu­ dents from 15 countries. Seventeen of the invited lectures and the Field Excursion Guide are included in this volume, together with 10 papers and six abstracts representing contributed poster sessions. Although more...

  4. Alternative Enhanced Chemical Cleaning Basic Studies Results FY09

    International Nuclear Information System (INIS)

    Due to the need to close waste storage tanks, chemical cleaning methods are needed for the effective removal of the heels. Oxalic acid is the preferred cleaning reagent for sludge heel dissolution, particularly for iron-based sludge, due to the strong complexing strength of the oxalate. However, the large quantity of oxalate added to the tank farm from oxalic acid based chemical cleaning has significant downstream impacts. Optimization of the oxalic acid cleaning process can potentially reduce the downstream impacts from chemical cleaning. To optimize oxalic acid usage, a detailed understanding of the chemistry of oxalic acid based sludge dissolution is required. Additionally, other acid systems may be required for specific waste components with low solubility in oxalic acid and as a means to reduce oxalic acid usage in general. Solubility tests were conducted using non-radioactive, pure metal phases known to be the primary phases present in High Level Waste sludge. The metal phases studied included the aluminum phases gibbsite and boehmite and the iron phases magnetite and hematite. Hematite and boehmite are expected to be the most difficult iron and aluminum phases to dissolve. These mineral phases have been identified in both SRS and Hanford High Level Waste sludge. Acids evaluated for dissolution included oxalic, nitric, and sulfuric acids. The results of the solubility tests indicate that oxalic and sulfuric acids are more effective for the dissolution of the primary sludge phases. For boehmite, elevated temperature will be required to promote effective phase dissolution in the acids studied. Literature reviews, thermodynamic modeling, and experimental results have all confirmed that pH control using a supplemental proton source (additional acid) is critical for minimization of oxalic acid usage during the dissolution of hematite. These results emphasize the importance of pH control in optimizing hematite dissolution in oxalic acid and may explain the somewhat

  5. Alternative Enhanced Chemical Cleaning Basic Studies Results FY09

    Energy Technology Data Exchange (ETDEWEB)

    Hay, M.; King, W.

    2010-05-05

    Due to the need to close waste storage tanks, chemical cleaning methods are needed for the effective removal of the heels. Oxalic acid is the preferred cleaning reagent for sludge heel dissolution, particularly for iron-based sludge, due to the strong complexing strength of the oxalate. However, the large quantity of oxalate added to the tank farm from oxalic acid based chemical cleaning has significant downstream impacts. Optimization of the oxalic acid cleaning process can potentially reduce the downstream impacts from chemical cleaning. To optimize oxalic acid usage, a detailed understanding of the chemistry of oxalic acid based sludge dissolution is required. Additionally, other acid systems may be required for specific waste components with low solubility in oxalic acid and as a means to reduce oxalic acid usage in general. Solubility tests were conducted using non-radioactive, pure metal phases known to be the primary phases present in High Level Waste sludge. The metal phases studied included the aluminum phases gibbsite and boehmite and the iron phases magnetite and hematite. Hematite and boehmite are expected to be the most difficult iron and aluminum phases to dissolve. These mineral phases have been identified in both SRS and Hanford High Level Waste sludge. Acids evaluated for dissolution included oxalic, nitric, and sulfuric acids. The results of the solubility tests indicate that oxalic and sulfuric acids are more effective for the dissolution of the primary sludge phases. For boehmite, elevated temperature will be required to promote effective phase dissolution in the acids studied. Literature reviews, thermodynamic modeling, and experimental results have all confirmed that pH control using a supplemental proton source (additional acid) is critical for minimization of oxalic acid usage during the dissolution of hematite. These results emphasize the importance of pH control in optimizing hematite dissolution in oxalic acid and may explain the somewhat

  6. Practical quantum digital signature

    Science.gov (United States)

    Yin, Hua-Lei; Fu, Yao; Chen, Zeng-Bing

    2016-03-01

    Guaranteeing nonrepudiation, unforgeability as well as transferability of a signature is one of the most vital safeguards in today's e-commerce era. Based on fundamental laws of quantum physics, quantum digital signature (QDS) aims to provide information-theoretic security for this cryptographic task. However, up to date, the previously proposed QDS protocols are impractical due to various challenging problems and most importantly, the requirement of authenticated (secure) quantum channels between participants. Here, we present the first quantum digital signature protocol that removes the assumption of authenticated quantum channels while remaining secure against the collective attacks. Besides, our QDS protocol can be practically implemented over more than 100 km under current mature technology as used in quantum key distribution.

  7. R&D studies for the development of a compact transmitter able to mimic the acoustic signature of a UHE neutrino interaction

    CERN Document Server

    Ardid, M; Bou-Cabo, M; Larosa, G; Mart\\inez-Mora, J A; Espinosa, V; Camarena, F; Ferri, M

    2011-01-01

    Calibration of acoustic neutrino telescopes with neutrino-like signals is an essential aspect to evaluate the feasibility of the technique and to know the efficiency of the detectors. However, it is not straightforward to have acoustic transmitters that, on one hand, are able to mimic the signature of a UHE neutrino interaction, that is, a bipolar acoustic pulse with the 'pancake' directivity, and, on the other hand, fulfill practical issues such as ease of deployment and operation. This is a non-trivial problem since it requires directive transducer with cylindrical symmetry for a broadband frequency range. Classical solutions using linear arrays of acoustic transducers result in long arrays with many elements, which increase the cost and the complexity for deployment and operation. In this paper we present the extension of our previous R&D studies using the parametric acoustic source technique by dealing with the cylindrical symmetry, and demonstrating that it is possible to use this technique for havin...

  8. Phosphorus effects on the mycelium and storage structures of an arbuscular mycorrhizal fungus as studied in the soil and roots by analysis of fatty acid signatures

    DEFF Research Database (Denmark)

    Olsson, P.A.; Bååth, E.; Jakobsen, I.

    1997-01-01

    The distribution of an arbuscular mycorrhizal (AM) fungus between soil and roots, and between mycelial and storage structures, was studied by use of the fatty acid signature 16:1 omega 5. Increasing the soil phosphorus level resulted in a decrease in the level of the fatty acid 16:1 omega 5 in the...... soil and roots. A similar decrease was detected by microscopic measurements of root colonization and of the length of AM fungal hyphae in the soil. The fatty acid 16:1 omega 5 was estimated from two types of lipids, phospholipids and neutral lipids, which mainly represent membrane lipids and storage...... lipids, respectively. The numbers of spores of the AM fungus formed in the soil correlated most closely, with neutral lipid fatty acid 16:1 omega 5, whereas the hyphal length in the soil correlated most closely with phospholipid fatty acid 16:1 omega 5. The fungal neutral lipid/phospholipid ratio in the...

  9. Typical signature of DNA damage in white blood cells: a pilot study on etheno adducts in Danish mother-newborn child pairs

    DEFF Research Database (Denmark)

    Arab, K; Pedersen, Marie; Nair, J;

    2009-01-01

    The impact of DNA damage commonly thought to be involved in chronic degenerative disease causation is particularly detrimental during fetal development. Within a multicenter study, we analyzed 77 white blood cell (WBC) samples from mother-newborn child pairs to see if imprinting of DNA damage in...... mother and newborn shows a similar pattern. Two adducts 1,N(6)-ethenodeoxyadenosine (epsilondA) and 3,N(4)-ethenodeoxycytidine (epsilondC) were measured by our ultrasensitive immunoaffinity (32)P-post-labeling method. These miscoding etheno-DNA adducts are generated by the reaction of lipid peroxidation...... arising from endogenous reactive aldehydes in WBC of both mother and newborn can be reliably assessed by epsilondA and epsilondC as biomarkers. The high correlation of etheno adduct levels in mother and child WBC suggests that a typical signature of DNA damage is induced similarly in fetus and mother...

  10. Phosphorus effects on the mycelium and storage structures of an arbuscular mycorrhizal fungus as studied in the soil and roots by analysis of fatty acid signatures

    DEFF Research Database (Denmark)

    Olsson, P.A.; Bååth, E.; Jakobsen, I.

    1997-01-01

    The distribution of an arbuscular mycorrhizal (AM) fungus between soil and roots, and between mycelial and storage structures, was studied by use of the fatty acid signature 16:1 omega 5. Increasing the soil phosphorus level resulted in a decrease in the level of the fatty acid 16:1 omega 5 in the...... extraradical mycelium was positively correlated with the level of root infection and thus decreased with increasing applications of P. The neutral lipid/phospholipid ratio indicated that at high P levels, less carbon was allocated to storage structures. At all levels of P applied, the major part of the AM...... fungus was found to he present outside the roots, as estimated from phospholipid fatty acid 16:1 omega 5. The ratio of extraradical biomass/intraradical biomass was not affected by the application of P, except for a decrease at the highest level of P applied....

  11. Mutations in the K+ channel signature sequence.

    OpenAIRE

    Heginbotham, L; Lu, Z; Abramson, T; MacKinnon, R

    1994-01-01

    Potassium channels share a highly conserved stretch of eight amino acids, a K+ channel signature sequence. The conserved sequence falls within the previously defined P-region of voltage-activated K+ channels. In this study we investigate the effect of mutations in the signature sequence of the Shaker channel on K+ selectivity determined under bi-ionic conditions. Nonconservative substitutions of two threonine residues and the tyrosine residue leave selectivity intact. In contrast, mutations a...

  12. Chemical-Free Cosmetics May Be Safer for Teen Girls, Study Suggests

    Science.gov (United States)

    ... nlm.nih.gov/medlineplus/news/fullstory_157640.html Chemical-Free Cosmetics May Be Safer for Teen Girls, Study Suggests Lower levels of hormone-disrupting chemicals seen in adolescents after trying products without potentially ...

  13. Rodent-repellent studies. III. Advanced studies in the evaluation of chemical repellents

    Science.gov (United States)

    Bellack, E.; DeWitt, J.B.

    1949-01-01

    In order to bridge the gap between preliminary screening of chemicals for potential rodent repellency and the application ofthese compounds to paper cartons, more advanced studies in the evaluation ofpromising materials have been carried out. These studies have resulted in: (1) a modification of the food acceptance technique which eliminates doubtful compounds and also provides a closer analogy to the ultimate goal, and (2) a method for rapidly testing chemicals incorporated in paper. When the results of these latter tests are expressed as a function of time, it can be shown that a distinct correlation exists between the deterrency exhibited by treated paper and the repellency of treated food.

  14. Studies on residue-free decontaminants for chemical warfare agents.

    Science.gov (United States)

    Wagner, George W

    2015-03-17

    Residue-free decontaminants based on hydrogen peroxide, which decomposes to water and oxygen in the environment, are examined as decontaminants for chemical warfare agents (CWA). For the apparent special case of CWA on concrete, H2O2 alone, without any additives, effectively decontaminates S-2-(diisopropylamino)ethyl O-ethyl methylphosphonothioate (VX), pinacolyl methylphosphorofluoridate (GD), and bis(2-choroethyl) sulfide (HD) in a process thought to involve H2O2 activation by surface-bound carbonates/bicarbonates (known H2O2 activators for CWA decontamination). A plethora of products are formed during the H2O2 decontamination of HD on concrete, and these are characterized by comparison to synthesized authentic compounds. As a potential residue-free decontaminant for surfaces other than concrete (or those lacking adsorbed carbonate/bicarbonate) H2O2 activation for CWA decontamination is feasible using residue-free NH3 and CO2 as demonstrated by reaction studies for VX, GD, and HD in homogeneous solution. Although H2O2/NH3/CO2 ("HPAC") decontaminants are active for CWA decontamination in solution, they require testing on actual surfaces of interest to assess their true efficacy for surface decontamination. PMID:25710477

  15. Study of physical chemical characteristics of a shungite

    Directory of Open Access Journals (Sweden)

    Maira Kazankapova

    2012-05-01

    Full Text Available The physico-chemical characteristics of shungite from the field of Kazakhstan ("Bakyrchik" and Russia ("Zazhegino" was studied by elemental analysis, IR- spectroscopy and electron microscopy. The content of carbon in the schungite field "Zazhegino" is 28,0-31,0 %,  in the field "Bakyrchik" - 15,0-19,0 %, in schungite concentrate  "Bakyrchik" is 40,0 ± 2,0 %.  IR-spectroscopic analysis have been shown that carboxyl groups appear in addition to the concentrate of polycyclic hydrocarbons containing methylene groups. Analysis of electron microscopy have been shown that as a result of enrichment by carbon, shungite can get a more developed surface structure and porosity.

  16. Quantum-chemical study of CHCl3-SO2 association

    Science.gov (United States)

    Hippler, Michael

    2005-11-01

    CHCl3-SO2 association is studied by high-level quantum-chemical calculations of stationary points of the dimer electronic potential-energy hypersurface, including correlated second-order Møller-Plesset and CCSD(T) calculations with basis sets up to 6-311++G(d,p). During geometry optimization, frequency, and energy calculations, a self-written computer code embedding the GAMESS ab initio program suite applies counterpoise correction of the basis set superposition error. A CH ⋯O hydrogen-bonded complex (ΔE0=-8.73kJ/mol) with a 2.4Å intermolecular H ⋯O distance and two very weak van der Waals complexes (ΔE0=-3.78 and -2.94kJ /mol) are located on the counterpoise-corrected potential-energy surface. The intermolecular interactions are characterized by Kitaura-Morokuma interaction energy decompositions and Mulliken electron population analyses. The unusual hydrogen bond is distinguished by a CH-bond contraction, a pronounced enhancement of the IR intensity and a shift to higher frequency ("blueshift") of the CH-stretching vibration compared to the CHCl3 monomer. Spectroscopy and association in liquid solution is also discussed; our results provide an alternative explanation for features in the CH-stretching vibration spectrum of chloroform dissolved in liquid sulfur dioxide which have been attributed previously to an intermolecular Fermi resonance.

  17. Chemical and environmental isotope study of precipitation in Syria

    International Nuclear Information System (INIS)

    The rain waters from a network covering 9 meteorological stations distributed mainly in the western part of Syria have been investigated using chemical and environmental isotope techniques during a period of 5 months from December 1989 to April 1990. The chemistry of rain waters falling over the mountainous stations shows a low solute concentration (16-55 mg/L) comparing with those falling over the coastal and anterior stations (36-150 mg/L). The study shows also that the rain water are generally characterized by a high deuterium excess (d = 19 per mille) comparing with that of the global meteoric waters (d = 10 per mille). Mean while, the estimated deuterium excess is found to be lower than that given for the eastern Mediterranean meteoric water (d = 22 per mille). The altitude effect is shown up by a depletion of heavy stable isotopes of about -0.23 per mille and -1.65 per mille per 100 meters for δoxygen-18 and δdeuterium, respectively. The spatial distribution pattern of tritium contents shows a gradual build up with the increasing distance from the Syrian coast. The weighted mean tritium content in rain waters falling over the country is estimated to be around 9.5 TU during the period of observation. (author). 22 refs, 9 figs, 2 tabs

  18. Comparative Study of Chemical Methods for Fuel Removal

    International Nuclear Information System (INIS)

    Full text: To extend the availability of ITER, tritium stored in the vessel has to be removed on a regular basis. The research on the fuel removal at Forschungszentrum Juelich has been concentrated in recent years on chemical methods including thermo-chemical erosion (TCE) also known as baking in reactive gases, glow-discharge conditioning (GDC) and ion-cyclotron wall conditioning (ICWC). The studies were conducted in the tokamak TEXTOR and in laboratory devices using pre-characterized samples with deuterated carbon layers. GDC, in contrast to TCE and ICWC, is not applicable in the presence of the nominal magnetic field. Our investigations showed that GDC can be operated at a magnetic field of up to 10 mT and is therefore compatible with the ferritic inserts foreseen in ITER. The TCE using oxygen as the removal gas can effectively be employed at elevated temperatures of at least 300°C. Plasma-based GDC and ICWC can also be applied at lower wall temperatures. TCE is equally efficient in cleaning from the wall surface as from the remote areas such as gaps of castellations. GDC is homogeneous along the wall surface except for small recessed areas like gaps. ICWC is typically inhomogeneous along the poloidal circumference. Applying the radial magnetic field, we were able to control the poloidal position of the main IC plasma production. Thus, some wall regions, e.g., the divertor, can selectively be exposed to ICWC. Owing to higher ion fluxes to the wall, ICWC activates a larger amount of neutrals than GDC, which then penetrate in gaps and clean gap walls efficiently. Removal rates with oxygen were typically by a factor of 3 - 10 higher than with hydrogen and ammonia and 10 - 30 than with nitrogen. The estimates using the highest removal rate for ICWC show that about 2 hours are needed to remove the layer deposited within one ITER pulse. The application of ammonia in TCE led to the pealing-off of layers, which is a potential dust production mechanism. However, it

  19. Potential Signatures of Semi-volatile Compounds Associated With Nuclear Processing

    Energy Technology Data Exchange (ETDEWEB)

    Probasco, Kathleen M.; Birnbaum, Jerome C.; Maughan, A. D.

    2002-06-01

    Semi-volatile chemicals associated with nuclear processes (e.g., the reprocessing of uranium to produce plutonium for nuclear weapons, or the separation of actinides from processing waste streams), can provide sticky residues or signatures that will attach to piping, ducting, soil, water, or other surface media. Volatile compounds, that are more suitable for electro-optical sensing, have been well studied. However, the semi-volatile compounds have not been well documented or studied. A majority of these semi-volatile chemicals are more robust than typical gaseous or liquid chemicals and can have lifetimes of several weeks, months, or years in the environment. However, large data gaps exist concerning these potential signature compounds and more research is needed to fill these data gaps so that important signature information is not overlooked or discarded. This report investigates key semi-volatile compounds associated with nuclear separations, identifies available chemical and physical properties, and discusses the degradation products that would result from hydrolysis, radiolysis and oxidation reactions on these compounds.

  20. USI/Chemplex/Quantum Chemical Co. Outfall Study, 1987

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Sediment samples collected in 1987 from the Quantum Chemical Corporation outfall on the Upper Mississippi River detected 14 polycyclic aromatic hydrocarbons...

  1. Probabilistic Model for Dynamic Signature Verification System

    Directory of Open Access Journals (Sweden)

    Chai Tong Yuen

    2011-11-01

    Full Text Available This study has proposed the algorithm for signature verification system using dynamic parameters of the signature: pen pressure, velocity and position. The system is proposed to read, analyze and verify the signatures from the SUSig online database. Firstly, the testing and reference samples will have to be normalized, re-sampled and smoothed through pre-processing stage. In verification stage, the difference between reference and testing signatures will be calculated based on the proposed thresholded standard deviation method. A probabilistic acceptance model has been designed to enhance the performance of the verification system. The proposed algorithm has reported False Rejection Rate (FRR of 14.8% and False Acceptance Rate (FAR of 2.64%. Meanwhile, the classification rate of the system is around 97%.

  2. A study on chemical composition and detection of chemical adulteration in tetra pack milk samples commercially available in Multan.

    Science.gov (United States)

    Awan, Adeela; Naseer, Misbah; Iqbal, Aasfa; Ali, Muhammad; Iqbal, Rehana; Iqbal, Furhan

    2014-01-01

    The aim of this study was to analyze and compare the chemical composition of 8 tetra pack milk samples, Olpers (S1), Haleeb (S2), Good milk (S3), Everyday (S4), Milk Pack (S5), Dairy Queen (S6), Dairy Umang (S7), Nurpur (S8) available in local markets and to detect the presence of various chemical adulterants in tetra pack milk samples in Southern Punjab (Pakistan). Density, pH, solid not fat, total solids, lactometer reading, specific gravity and fat contents were analyzed to determine the chemical composition of milk samples. Our results revealed that all the studied parameters had statistically non significant differences (P>0.05) except total fat in milk samples which was significantly different (P=0.03) among the 8 studied milk samples. Presence of a number of chemical adulterants, formalin, cane sugar, starch, glucose, ammonium sulphate, salt, pulverized soap, detergents, skim milk powder, benzoic acid, salicylic acid, borax, boric acid and alkalinity were also detected in milk samples following standard procedures. Results indicated that formalin, cane sugar, glucose, alkalinity and benzoic acid were present in all samples while salt test was positive only for Olper milk. All other studied adulterants were not detected in 8 milk samples under study. % fat was the only significantly different feature among the studied milk quality parameters with S8 containing lowest while S5 having the maximum % fat. PMID:24374447

  3. Aperiodic logarithmic signatures

    CERN Document Server

    Baumeister, Barbara

    2011-01-01

    In this paper we propose a method to construct logarithmic signatures which are not amalgamated transversal and further do not even have a periodic block. The latter property was crucial for the successful attack on the system MST3 by Blackburn et al. [1]. The idea for our construction is based on the theory in Szab\\'o's book about group factorizations [12].

  4. The dark energy signature

    International Nuclear Information System (INIS)

    Though the concept of a dark energy driven accelerating universe was introduced by the author in 1997, to date dark energy itself, as described below has remained a paradigm. We quickly review these and find a second cosmological signature of the 1997 model, consistent with latest observations. (author)

  5. UV missile plume signatures

    NARCIS (Netherlands)

    Neele, F.P.; Schleijpen, H.M.A.

    2002-01-01

    As a result of the deployment of UV missile warning systems, recent years have seen an increasing interest in threat assessment in the UV band. Unfortunately, due to the different nature of the physical processes that are needed to describe a missile signature in the UV, available codes for the IR c

  6. Study of chemical and physical properties of irradiated Guar Gum

    International Nuclear Information System (INIS)

    This study was carried out to evaluate the effect of different gamma radiation doses to decontamination of micro-organisms present in Guar Gum powder. As well as to study the effect of radiation on the chemical and physical properties of the carbohydrate components of the Gum's material. Two types of samples were used in this study (powder and liquid). All samples were collected from commercially available Guar Gum (G G), which were obtained from the company (Sudanese Guar Gum ltd). Samples putted in polyethylene tightly closed container, then irradiated by applying different doses (2.5, 5, 7.5, 10, 20,30,40,and 50 kGy) from Co-60 source at room temperature in air. And take zero kGy as control. Irradiated powder samples of (2.5, 5, 7.5, 10 kGy) were investigated for contamination by using growth media agar and the result showed that 2.5 kGy is appropriate dose to remove the contamination of the samples. And then analyzed using fourier transform infrared (FTTR) x-ray fluorescence (X RF) and spectroscopy. The FTIR spectroscopy results suggested that there were no major chemical functional group transformation during irradiation. No change occurs by using low dose as 2.5 kGy. Also evaluation impact of radiation on liquid Samples (Aqueous solutions prepared in tow concentration of 1% and 5% wv that is by exposing the samples to the same dose of gamma rays) the effect of irradiation on it were investigated by using ultra violet spectroscopy ( UV.Vis), results showed that low dose has steeply effect in solutions specially in low concentration, it was more pronoun than that in high concentration, high dose has made change similar to that it made in powder. Also for both concentrations of liquid samples and for solutions made of irradiated powder pH measured and viscosity which used in investigations of molecular weight of liquid and powder, comparing the results of impact in the form of powder with the results of effects in the solutions found that the effects of

  7. Crossed molecular beam studies of atmospheric chemical reaction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jingsong

    1993-04-01

    The dynamics of several elementary chemical reactions that are important in atmospheric chemistry are investigated. The reactive scattering of ground state chlorine or bromine atoms with ozone molecules and ground state chlorine atoms with nitrogen dioxide molecules is studied using a crossed molecular beams apparatus with a rotatable mass spectrometer detector. The Cl + O{sub 3} {yields} ClO + O{sub 2} reaction has been studied at four collision energies ranging from 6 kcal/mole to 32 kcal/mole. The derived product center-of-mass angular and translational energy distributions show that the reaction has a direct reaction mechanism and that there is a strong repulsion on the exit channel. The ClO product is sideways and forward scattered with respect to the Cl atom, and the translational energy release is large. The Cl atom is most likely to attack the terminal oxygen atom of the ozone molecule. The Br + O{sub 3} {yields} ClO + O{sub 2} reaction has been studied at five collision energies ranging from 5 kcal/mole to 26 kcal/mole. The derived product center-of-mass angular and translational energy distributions are quite similar to those in the Cl + O{sub 3} reaction. The Br + O{sub 3} reaction has a direct reaction mechanism similar to that of the Cl + O{sub 3} reaction. The electronic structure of the ozone molecule seems to play the central role in determining the reaction mechanism in atomic radical reactions with the ozone molecule. The Cl + NO{sub 2} {yields} ClO + NO reaction has been studied at three collision energies ranging from 10.6 kcal/mole to 22.4 kcal/mole. The center-of-mass angular distribution has some forward-backward symmetry, and the product translational energy release is quite large. The reaction proceeds through a short-lived complex whose lifetime is less than one rotational period. The experimental results seem to show that the Cl atom mainly attacks the oxygen atom instead of the nitrogen atom of the NO{sub 2} molecule.

  8. Studies of coupled chemical and catalytic coal conversion methods

    Energy Technology Data Exchange (ETDEWEB)

    Stock, L.M.

    1988-01-01

    Liquefaction of coal by depolymerization in an organic solvent has been studied for several years. The liquefied coal extract which results from such a process is far more suitable for conversion into liquid fuel by hydrogenolysis than is the untreated coal. Investigations on the chemical structure and the reactive sites of coal can help to select useful reactions for the production of liquids from coal. Sternberg et al. demonstrated that the reductive alkylation method transforms bituminous coal into an enormously soluble substance, irrespective of the mild reaction conditions. The effectiveness of newly introduced alkyl groups for the disruption of intermolecular hydrogen bonds and pi-pi interactions between the aromatic sheets in coal macromolecules has been recognized. It has been reported by Ignasiak et al. that a C-alkylabon reaction using sodium or potassium amide in liquid ammonia can be used to introduce alkyl groups at acidic carbon sites. A method has been developed recently in this laboratory for the solubilization of high rank coals. In the previous reports it was shown that n-butyl lithium and potassium t-butoxide in refluxing heptane produced coal anions which could be alkylated with different alkyl halides. Such alkylated coals were soluble up to 92% in solvents like pyridine. Though the solubilization of coal depended very much on the length of the alkyl group, it also depended very much on the nature of the base used. Strong bases like n-butyl lithium (pKa=42) can cause proton abstraction from aromatic structures, if the more acidic benzylic protons are absent. The utility of this procedure, initially developed and used by Miyake and Stock, has now been tested with the high oxygen containing, low rank Illinois No. 6 and Wyodak coals.

  9. Explosives signatures and analysis

    Science.gov (United States)

    Fountain, Augustus Way, III; Oyler, Jonathan M.; Ostazeski, Stanley A.

    2008-04-01

    The challenge of sampling explosive materials for various high threat military and civilian operational scenarios requires the community to identify and exploit other chemical compounds within the mixtures that may be available to support stand-off detection techniques. While limited surface and vapor phase characterization of IEDs exist, they are insufficient to guide the future development and evaluation of field deployable explosives detection (proximity and standoff) capabilities. ECBC has conducted a limited investigation of three artillery ammunition types to determine what chemical vapors, if any, are available for sensing; the relative composition of the vapors which includes the more volatile compounds in munitions, i.e., plastersizers and binders; and the sensitivity needed detect these vapors at stand-off. Also in partnership with MIT-Lincoln Laboratory, we performed a background measurement campaign at the National Training Center to determine the baseline ambient amounts and variability of nitrates and nitro-ester compounds as vapors, particulates, and on surfaces; as well as other chemical compounds related to non-energetic explosive additives. Environmental persistence studies in contexts relevant to counter-IED sensing operations, such as surface residues, are still necessary.

  10. A PRACTICAL PROXY SIGNATURE SCHEME

    Directory of Open Access Journals (Sweden)

    Sattar Aboud

    2012-01-01

    Full Text Available A proxy signature scheme is a variation of the ordinary digital signature scheme which enables a proxy signer to generate signatures on behalf of an original signer. In this paper, we present two efficient types of proxy signature scheme. The first one is the proxy signature for warrant partial delegation combines an advantage of two well known warrant partial delegation schemes. This proposed proxy signature scheme is based on the difficulty of solving the discrete logarithm problem. The second proposed scheme is based on threshold delegation the proxy signer power to sign the message is share. We claim that the proposed proxy signature schemes meet the security requirements and more practical than the existing proxy signature schemes.

  11. Study on New Approaches for extended chemical management and REACH

    DEFF Research Database (Denmark)

    Lee, Jihyun

    2014-01-01

    existing chemical regulations in view of protecting vulnerable populations from “excessive total risk” and to explore the possibilities for improvement. Firstly, the completeness of the REACH exposure scenario was reviewed with the finding that the current scenario does not take into account territorial...... without controlling the quality of recycled materials, increased recycling of resources in a circular economy might increase undesirable recycling of micro-pollutants. Finally, a systemic approach based on sustainable resource flows was proposed for extended chemical management and the role of REACH in a...

  12. EXPERIMENTAL STUDY OF CHEMICAL CHOLECYSTECTOMY: OBSERVATION OF PATHOLOGICAL CHANGES

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective: TO verify through animal experiment the validity of chemical cholecystectomy . Methods: The experimental objects seven healthy juvenile pigs,hardener was infused into the gallbladder,after infusion the samples were collected by pathoiogical examination , according to the different duration under anesthestize. Reslts:The mucous destructive and digestive process remained with one week, the inflammatory reacton in two weeks,the chronic inflatoy reaction compained a a great deal of granu lation tissue and scar formation occurred in 4th-8th week,10 weeks latter,the inflmmatory reaction reduced ,and scar tissue formed. Conclusion: Chemical cholecystectomy is safe and reliable in clinical.

  13. EXPERIMENTAL STUDY OF CHEMICAL CHOLECYSTECTOMY OF PATHOLOGIC OBSERVATION

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective:To verify through animal experiment the validity of chemical cholecystectomy.Mothods:The expermental objects seven healthy juvenile pigs,hardener was infused into the gallbladder,after infusion the sapmles were collected by pathological examination,according to the different duration under anesthestize.Results:The mucous destructive and digestive process remained with one week,the inflammatory reaction in two weeks,the chronic inflammatory reaction compained a great deal of granulation tissue and scar formation occurred in 4th-8th week,10 weeks latter,the inflammatory reaction reduced,and scar tissue formed.Conlusion:Chemical cholecystecomy is safe and reliable in clinic.

  14. Laser studies of chemical reaction and collision processes

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, G. [Columbia Univ., New York, NY (United States)

    1993-12-01

    This work has concentrated on several interrelated projects in the area of laser photochemistry and photophysics which impinge on a variety of questions in combustion chemistry and general chemical kinetics. Infrared diode laser probes of the quenching of molecules with {open_quotes}chemically significant{close_quotes} amounts of energy in which the energy transferred to the quencher has, for the first time, been separated into its vibrational, rotational, and translational components. Probes of quantum state distributions and velocity profiles for atomic fragments produced in photodissociation reactions have been explored for iodine chloride.

  15. Study about chemical and radiological toxicity of rare earths

    International Nuclear Information System (INIS)

    The maximum permissible concentration in workplace air for an admixture of rare earths is calculated to be 1.47 mg/m3 of air. This value takes into account the biological mean-life of those chemical elements in human body and acute toxicological data. A simplified mathematical models is done that describes the body content of this product as a time function, for cronic intoxication by air particulate inhalation. Under the radiological point of view the limit calculated for the air concentration is about 100 mg/m3, showing that the chemical toxity of these products is predominant. (Author)

  16. Chemical Risk Evaluation: A Case Study in an Automotive Air Conditioner Production Facility

    OpenAIRE

    Tengku Hanidza T.I.

    2010-01-01

    There has been limited knowledge on worker’s exposure to chemicals used in the automotive industries. The purpose of this study is to assess chemical risk and to determine the adequacy of the existing control measures to reduce chemical exposure. A cross sectional survey was conducted in a factory involving installation and servicing of automotive air conditioner units. Qualitative exposure assessment was carried out following the Malaysian Chemical Health Risk Assessment Manual (CHRA). There...

  17. Systematic quantum chemical study of DNA-base tautomers.

    Science.gov (United States)

    Piacenza, M; Grimme, S

    2004-01-15

    The relative energies of the energetically low-lying tautomers of pyridone, cytosine, uracil, thymine, guanine, and iso-cytosine are studied by a variety of different quantum chemical methods. In particular, we employ density functional theory (DFT) using the six functionals HCTH407, PBE, BP86, B-LYP, B3-LYP, and BH-LYP, and the ab initio methods Hartree-Fock (HF), standard second-order Møller-Plesset perturbation theory (MP2), an improved version of it (SCS-MP2), and quadratic configuration interaction including single and double excitations (QCISD) and perturbative triple corrections [QCISD(T)]. A detailed basis set study is performed for the formamide/formamidic acid tautomeric pair. In general, large AO basis sets of at least valence triple-zeta quality including f-functions (TZV) are employed, which are found to be necessary for an accurate energetic description of the various structures. The performance of the more approximate methods is evaluated with QCISD(T)/TZV(2df,2dp) data taken as reference. In general it is found that DFT is not an appropriate method for the problem. For the tautomers of pyridone and cytosine, most density functionals, including the popular B3-LYP hybrid, predict a wrong energetic order, and only for guanine, the correct sequence of tautomers is obtained with all functionals. Out of the density functionals tested, BH-LYP, which includes a rather large fraction of HF exchange, performs best. A consistent description of the nonaromatic versus aromatic tautomers seems to be a general problem especially for pure, nonhybrid functionals. Tentatively, this could be assigned to the exchange potentials used while the functional itself, including the correlation part, seems to be appropriate. Out of the ab initio methods tested, the new SCS-MP2 approach seems to perform best because it effectively reduces some outliers obtained with standard MP2. It outperforms the much more costly QCISD method and seems to be a very good compromise between

  18. Genetic signatures of heroin addiction

    Science.gov (United States)

    Chen, Shaw-Ji; Liao, Ding-Lieh; Shen, Tsu-Wang; Yang, Hsin-Chou; Chen, Kuang-Chi; Chen, Chia-Hsiang

    2016-01-01

    Abstract Heroin addiction is a complex psychiatric disorder with a chronic course and a high relapse rate, which results from the interaction between genetic and environmental factors. Heroin addiction has a substantial heritability in its etiology; hence, identification of individuals with a high genetic propensity to heroin addiction may help prevent the occurrence and relapse of heroin addiction and its complications. The study aimed to identify a small set of genetic signatures that may reliably predict the individuals with a high genetic propensity to heroin addiction. We first measured the transcript level of 13 genes (RASA1, PRKCB, PDK1, JUN, CEBPG, CD74, CEBPB, AUTS2, ENO2, IMPDH2, HAT1, MBD1, and RGS3) in lymphoblastoid cell lines in a sample of 124 male heroin addicts and 124 male control subjects using real-time quantitative PCR. Seven genes (PRKCB, PDK1, JUN, CEBPG, CEBPB, ENO2, and HAT1) showed significant differential expression between the 2 groups. Further analysis using 3 statistical methods including logistic regression analysis, support vector machine learning analysis, and a computer software BIASLESS revealed that a set of 4 genes (JUN, CEBPB, PRKCB, ENO2, or CEBPG) could predict the diagnosis of heroin addiction with the accuracy rate around 85% in our dataset. Our findings support the idea that it is possible to identify genetic signatures of heroin addiction using a small set of expressed genes. However, the study can only be considered as a proof-of-concept study. As the establishment of lymphoblastoid cell line is a laborious and lengthy process, it would be more practical in clinical settings to identify genetic signatures for heroin addiction directly from peripheral blood cells in the future study. PMID:27495086

  19. Two Improved Digital Signature Schemes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, two improved digital signature schemes are presented based on the design of directed signaturescheme [3]. The peculiarity of the system is that only if the scheme is specific recipient, the signature is authenticated.Since the scheme adds the screen of some information parameters, the difficulty of deciphered keys and the security ofdigital signature system are increased.

  20. Pre-earthquake signatures in atmosphere/ionosphere and their potential for short-term earthquake forecasting. Case studies for 2015

    Science.gov (United States)

    Ouzounov, Dimitar; Pulinets, Sergey; Davidenko, Dmitry; Hernández-Pajares, Manuel; García-Rigo, Alberto; Petrrov, Leonid; Hatzopoulos, Nikolaos; Kafatos, Menas

    2016-04-01

    We are conducting validation studies on temporal-spatial pattern of pre-earthquake signatures in atmosphere and ionosphere associated with M>7 earthquakes in 2015. Our approach is based on the Lithosphere Atmosphere Ionosphere Coupling (LAIC) physical concept integrated with Multi-sensor-networking analysis (MSNA) of several non-correlated observations that can potentially yield predictive information. In this study we present two type of results: 1/ prospective testing of MSNA-LAIC for M7+ in 2015 and 2:/ retrospective analysis of temporal-spatial variations in atmosphere and ionosphere several days before the two M7.8 and M7.3 in Nepal and M8.3 Chile earthquakes. During the prospective test 18 earthquakes M>7 occurred worldwide, from which 15 were alerted in advance with the time lag between 2 up to 30 days and with different level of accuracy. The retrospective analysis included different physical parameters from space: Outgoing long-wavelength radiation (OLR obtained from NPOES, NASA/AQUA) on the top of the atmosphere, Atmospheric potential (ACP obtained from NASA assimilation models) and electron density variations in the ionosphere via GPS Total Electron Content (GPS/TEC). Concerning M7.8 in Nepal of April 24, rapid increase of OLR reached the maximum on April 21-22. GPS/TEC data indicate maximum value during April 22-24 periods. Strong negative TEC anomaly was detected in the crest of EIA (Equatorial Ionospheric Anomaly) on April 21st and strong positive on April 24th, 2015. For May 12 M7.3 aftershock similar pre- earthquake patterns in OLR and GPS/TEC were observed. Concerning the M8.3 Chile of Sept 16, the OLR strongest transient feature was observed of Sept 12. GPS/TEC analysis data confirm abnormal values on Sept 14. Also on the same day the degradation of EIA and disappearance of the crests of EIA as is characteristic for pre-dawn and early morning hours (11 LT) was observed. On Sept 16 co-seismic ionospheric signatures consistent with defined circular

  1. Accelerating Wave Function Convergence in Interactive Quantum Chemical Reactivity Studies

    CERN Document Server

    Mühlbach, Adrian H; Reiher, Markus

    2015-01-01

    The inherently high computational cost of iterative self-consistent-field (SCF) methods proves to be a critical issue delaying visual and haptic feedback in real-time quantum chemistry. In this work, we introduce two schemes for SCF acceleration. They provide a guess for the initial density matrix of the SCF procedure generated by extrapolation techniques. SCF optimizations then converge in fewer iterations, which decreases the execution time of the SCF optimization procedure. To benchmark the proposed propagation schemes, we developed a test bed for performing quantum chemical calculations on sequences of molecular structures mimicking real-time quantum chemical explorations. Explorations of a set of six model reactions employing the semi-empirical methods PM6 and DFTB3 in this testing environment showed that the proposed propagation schemes achieved speedups of up to thirty percent as a consequence of a reduced number of SCF iterations.

  2. Accelerating Wave Function Convergence in Interactive Quantum Chemical Reactivity Studies.

    Science.gov (United States)

    Mühlbach, Adrian H; Vaucher, Alain C; Reiher, Markus

    2016-03-01

    The inherently high computational cost of iterative self-consistent field (SCF) methods proves to be a critical issue delaying visual and haptic feedback in real-time quantum chemistry. In this work, we introduce two schemes for SCF acceleration. They provide a guess for the initial density matrix of the SCF procedure generated by extrapolation techniques. SCF optimizations then converge in fewer iterations, which decreases the execution time of the SCF optimization procedure. To benchmark the proposed propagation schemes, we developed a test bed for performing quantum chemical calculations on sequences of molecular structures mimicking real-time quantum chemical explorations. Explorations of a set of six model reactions employing the semi-empirical methods PM6 and DFTB3 in this testing environment showed that the proposed propagation schemes achieved speedups of up to 30% as a consequence of a reduced number of SCF iterations. PMID:26788887

  3. Chemical and pharmacological studies of the plants from genus Celastrus.

    Science.gov (United States)

    Su, Xiao-Hui; Zhang, Man-Li; Zhan, Wen-Hong; Huo, Chang-Hong; Shi, Qing-Wen; Gu, Yu-Cheng; Kiyota, Hiromasa

    2009-02-01

    The plants of genus Celastrus, distributed in Asia, have been used as natural insecticides and folk medicines to treat fever, chill, joint pain, edema, rheumatoid arthritis, and bacterial infection in China for a long time. This contribution reviews the chemical constituents, isolated from the plants in genus Celastrus in the past few decades, and their biological activities. The compounds listed are sesquiterpenes (beta-agarofurans), diterpenes, triterpenes, alkaloids, and flavonoids. PMID:19235157

  4. Green strength sustainability: a case study of chemical engineering students

    OpenAIRE

    Avsec, Stanislav; Kaučič, Branko

    2015-01-01

    Green chemistry is a relatively new area of science and technology aimed at improving chemical processes and thereby avoiding negative impacts on human health, safety, and the environment (EHS). It is based on careful selection of raw materials for the production of various products, excluding the use of hazardous substances. The field of green chemistry has received much attention from the scientific and industrial communities in almost every highly industrialized nation. It i...

  5. Chemical Arsenal for the Study of O-GlcNAc

    Directory of Open Access Journals (Sweden)

    Eun J. Kim

    2011-02-01

    Full Text Available The concepts of both protein glycosylation and cellular signaling have been influenced by O-linked-β-N-acetylglucosamine (O-GlcNAc modification (O-GlcNAcylation on the hydroxyl group of serine or threonine residues. Unlike conventional protein glycosylation, O-GlcNAcylation is localized in the nucleocytoplasm and its cycling is a dynamic process that operates in a highly regulated manner in response to various cellular stimuli. These characteristics render O-GlcNAcylation similar to phosphorylation, which has long been considered a major regulatory mechanism in cellular processes. Various efficient chemical approaches and novel mass spectrometric (MS techniques have uncovered numerous O-GlcNAcylated proteins that are involved in the regulation of many important cellular events. These discoveries imply that O-GlcNAcylation is another major regulator of cellular signaling. However, in contrast to phosphorylation, which is regulated by hundreds of kinases and phosphatases, dynamic O-GlcNAc cycling is catalyzed by only two enzymes: uridine diphospho-N-acetyl-glucosamine:polypeptide β-N-acetylglucosaminyl transferase (OGT and β-D-N-acetylglucosaminidase (OGA. Many useful chemical tools have recently been used to greatly expand our understanding of the extensive crosstalk between O-GlcNAcylation and phosphorylation and hence of cellular signaling. This review article describes the various useful chemical tools that have been developed and discusses the considerable advances made in the O-GlcNAc field.

  6. Analysis and computational dissection of molecular signature multiplicity.

    Directory of Open Access Journals (Sweden)

    Alexander Statnikov

    2010-05-01

    Full Text Available Molecular signatures are computational or mathematical models created to diagnose disease and other phenotypes and to predict clinical outcomes and response to treatment. It is widely recognized that molecular signatures constitute one of the most important translational and basic science developments enabled by recent high-throughput molecular assays. A perplexing phenomenon that characterizes high-throughput data analysis is the ubiquitous multiplicity of molecular signatures. Multiplicity is a special form of data analysis instability in which different analysis methods used on the same data, or different samples from the same population lead to different but apparently maximally predictive signatures. This phenomenon has far-reaching implications for biological discovery and development of next generation patient diagnostics and personalized treatments. Currently the causes and interpretation of signature multiplicity are unknown, and several, often contradictory, conjectures have been made to explain it. We present a formal characterization of signature multiplicity and a new efficient algorithm that offers theoretical guarantees for extracting the set of maximally predictive and non-redundant signatures independent of distribution. The new algorithm identifies exactly the set of optimal signatures in controlled experiments and yields signatures with significantly better predictivity and reproducibility than previous algorithms in human microarray gene expression datasets. Our results shed light on the causes of signature multiplicity, provide computational tools for studying it empirically and introduce a framework for in silico bioequivalence of this important new class of diagnostic and personalized medicine modalities.

  7. ALTERNATIVE AND ENHANCED CHEMICAL CLEANING: BASIC STUDIES RESULTS FY2010

    Energy Technology Data Exchange (ETDEWEB)

    King, W.; Hay, M.

    2011-01-24

    In an effort to develop and optimize chemical cleaning methods for the removal of sludge heels from High Level Waste tanks, solubility tests have been conducted using nonradioactive, pure metal phases. The metal phases studied included the aluminum phase gibbsite and the iron phases hematite, maghemite, goethite, lepidocrocite, magnetite, and wustite. Many of these mineral phases have been identified in radioactive, High Level Waste sludge at the Savannah River and Hanford Sites. Acids evaluated for dissolution included oxalic, nitric, and sulfuric acids and a variety of other complexing organic acids. The results of the solubility tests indicate that mixtures of oxalic acid with either nitric or sulfuric acid are the most effective cleaning solutions for the dissolution of the primary metal phases in sludge waste. Based on the results, optimized conditions for hematite dissolution in oxalic acid were selected using nitric or sulfuric acid as a supplemental proton source. Electrochemical corrosion studies were also conducted (reported separately; Wiersma, 2010) with oxalic/mineral acid mixtures to evaluate the effects of these solutions on waste tank integrity. The following specific conclusions can be drawn from the test results: (1) Oxalic acid was shown to be superior to all of the other organic acids evaluated in promoting the dissolution of the primary sludge phases. (2) All iron phases showed similar solubility trends in oxalic acid versus pH, with hematite exhibiting the lowest solubility and the slowest dissolution. (3) Greater than 90% hematite dissolution occurred in oxalic/nitric acid mixtures within one week for two hematite sources and within three weeks for a third hematite sample with a larger average particle size. This dissolution rate appears acceptable for waste tank cleaning applications. (4) Stoichiometric dissolution of iron phases in oxalic acid (based on the oxalate concentration) and the formation of the preferred 1:1 Fe to oxalate complex

  8. Proteomic signatures of infertile men with clinical varicocele and their validation studies reveal mitochondrial dysfunction leading to infertility

    Science.gov (United States)

    Agarwal, Ashok; Sharma, Rakesh; Samanta, Luna; Durairajanayagam, Damayanthi; Sabanegh, Edmund

    2016-01-01

    To study the major differences in the distribution of spermatozoa proteins in infertile men with varicocele by comparative proteomics and validation of their level of expression. The study-specific estimates for each varicocele outcome were combined to identify the proteins involved in varicocele-associated infertility in men irrespective of stage and laterality of their clinical varicocele. Expression levels of 5 key proteins (PKAR1A, AK7, CCT6B, HSPA2, and ODF2) involved in stress response and sperm function including molecular chaperones were validated by Western blotting. Ninety-nine proteins were differentially expressed in the varicocele group. Over 87% of the DEP involved in major energy metabolism and key sperm functions were underexpressed in the varicocele group. Key protein functions affected in the varicocele group were spermatogenesis, sperm motility, and mitochondrial dysfunction, which were further validated by Western blotting, corroborating the proteomics analysis. Varicocele is essentially a state of energy deprivation, hypoxia, and hyperthermia due to impaired blood supply, which is corroborated by down-regulation of lipid metabolism, mitochondrial electron transport chain, and Krebs cycle enzymes. To corroborate the proteomic analysis, expression of the 5 identified proteins of interest was validated by Western blotting. This study contributes toward establishing a biomarker “fingerprint” to assess sperm quality on the basis of molecular parameters. PMID:26732106

  9. Bandwidth Study on Energy Use and Potential Energy Saving Opportunities in U.S. Chemical Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Sabine Brueske, Caroline Kramer, Aaron Fisher

    2015-06-01

    Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. chemical manufacturing. The study relies on multiple sources to estimate the energy used in the production of 74 individual chemicals, representing 57% of sector-wide energy consumption. Energy savings opportunities for individual chemicals and for 15 subsectors of chemicals manufacturing are based on technologies currently in use or under development; these potential savings are then extrapolated to estimate sector-wide energy savings opportunity.

  10. Weight loss predictability by plasma metabolic signatures in adults with obesity and morbid obesity of the DiOGenes study

    DEFF Research Database (Denmark)

    Stroeve, Johanna H M; Saccenti, Edoardo; Bouwman, Jildau; Dane, Adrie; Strassburg, Katrin; Vervoort, Jacques; Hankemeier, Thomas; Astrup, Arne; Smilde, Age K; van Ommen, Ben; Saris, Wim H M

    2016-01-01

    kcal) for 8 weeks. Men (N = 236) and women (N = 431) as well as groups with overweight/obesity and morbid obesity were studied separately. The relation between the metabolic status before weight loss and weight loss was assessed by stepwise regression on multiple data sets, including anthropometric...... parameters, NMR-based plasma metabolites, and LC-MS-based plasma lipid species. RESULTS: Maximally, 57% of the variation in weight loss success can be predicted by baseline parameters. The most powerful predictive models were obtained in subjects with morbid obesity. In these models, the metabolites most...

  11. R and D studies for the development of a compact transmitter able to mimic the acoustic signature of a UHE neutrino interaction

    International Nuclear Information System (INIS)

    Calibration of acoustic neutrino telescopes with neutrino-like signals is essential to evaluate the feasibility of the technique and to know the efficiency of the detectors. However, it is not straightforward to have acoustic transmitters that, on one hand, are able to mimic the signature of a UHE neutrino interaction, that is, a bipolar acoustic pulse with the ‘pancake’ directivity, and on the other hand, fulfil practical issues such as ease of deployment and operation. This is a non-trivial problem since it requires directive transducer with cylindrical symmetry for a broadband frequency range. Classical solutions using linear arrays of acoustic transducers result in long arrays with many elements, which increase the cost and the complexity for deployment and operation. In this paper we present the extension of our previous R and D studies using the parametric acoustic source technique by dealing with the cylindrical symmetry and demonstrating that it is possible to use this technique for having a compact solution that could be much more easily included in neutrino telescope infrastructures or used in specific sea campaigns for calibration.

  12. Oceanographic signatures and pressure monitoring of seafloor vertical deformation in near-coastal, shallow-water areas: a case study from Santorini Caldera.

    Science.gov (United States)

    Vilaseca, Géraud; Deplus, Christine; Escartin, Javier; Ballu, Valérie; Nomikou, Paraskevi; Mével, Catherine; Andreani, Muriel

    2016-04-01

    Bottom pressure, tilt and seawater physical-properties were monitored for a year using two instruments within the immerged Santorini caldera (Greece). Piggy-backed on the CALDERA2012 cruise, this geodetic experiment was designed to monitor evolution of the 2011-2012 Santorini unrest. Conducted during a quiescent period, it allowed us to study oceanographic and atmospheric signal in our data series. We observe periodic oceanographic signals associated with tides, and seiches that are likely linked to both the caldera and Cretan basin geometries. In winter, the caldera witnesses sudden cooling events that tilt an instrument towards the Southeast, indicating cold-water influx likely originating from the north-western passage between Thirasia and Oia. We do not obtain evidence of long-term vertical seafloor deformation from the pressure signal, although it may be masked by instrumental drift. However, tilt data suggests a local seafloor tilt event ~1 year after the end of the unrest period which could be consistent with inflation under or near Nea Kameni. In addition, we illustrate that tilt sensor can roughly record seismic induced ground motion which in our case led to a shift in sensors attitude for one seismic event. Seafloor geodetic data recorded at the bottom of the Santorini caldera illustrates that the oceanographic signature is an important part of the signal, which needs to be considered for monitoring volcanic or geological seafloor deformation in shallow-water and/or nearshore areas.

  13. An Exploratory Study of The Malaysian Chemical Industry

    OpenAIRE

    Lee, Chun Hooi

    2008-01-01

    With the force of globalization and huge product commoditization pressure in the Business-To-Business (B2B) markets, the B2B marketers have turn their attention to branding in order to tap the brand potential from their product and corporate name. The main objective of this dissertation is to explore the industrial brand value and B2B brand equity in the context of the Malaysian chemical industry. The industrial brand value is explored by using the pinwheel model proposed by Mudambi et al (19...

  14. Fundamental studies of chemical vapor deposition diamond growth processes

    International Nuclear Information System (INIS)

    We are developing laser spectroscopic techniques to foster a fundamental understanding of diamond film growth by hot filament chemical vapor deposition (CVD). Several spectroscopic techniques are under investigation to identify intermediate species present in the bulk reactor volume, the thin active volume immediately above the growing film, and the actual growing surface. Such a comprehensive examination of the overall deposition process is necessary because a combination of gas phase and surface chemistry is probably operating. Resonantly enhanced multiphoton ionization (REMPI) techniques have been emphasized. A growth rector that permits through-the-substrate gas sampling for REMPI/time-of-flight mass spectroscopy has been developed. 7 refs., 2 figs

  15. [Study on chemical constituents of Drosera peltata var. multisepala].

    Science.gov (United States)

    Li, Lin; Huang, Jin; Xu, Xianghua; Zhang, Yao; Cheng, Kejun; Yu, Peizhong

    2012-01-01

    Chemical investigatation of Drosera peltata var. multisepala led to the isolation of eleven compounds using various chromatographic techniques. The structures of these compounds were elucidated as isoshinanolone-4-O-beta-D-glucoside (1), isoshinanolone (2), epi-isoshinanolone (3), plumbagin (4), droserone (5), droserone-5-O-glucoside (6), quercetin (7), kaempferol (8) , gossypetin-8-O-glucoside (9), 3,3'-dimethoxy ellagic acid (10), and ellagic acid (11) by their physicochemical properties and spectral data analysis. Compound 1 was a new compound. Compounds 3, 8, 10, and 11 were isolated from this plant for the first time. PMID:22737855

  16. Physico-chemical studies on samarium soaps in solid state

    International Nuclear Information System (INIS)

    The physico-chemical characteristics of samarium soaps (caproate and caprate) in solid state were investigated by IR, X-ray diffraction and TGA measurements. The IR results revealed that the fatty acids exist in dimeric state through hydrogen bonding and samarium soaps possess partial ionic character. The X-ray diffraction measurements were used to calculate the long spacings and the results confirmed the double layer structure of samarium soaps. The decomposition reaction was found kinetically of zero order and the values of energy of activation for the decomposition process for caproate and caprate were found to be 8,0 and 7,8 kcal mol-1, respectively. (Authors)

  17. Collagen-curcumin interaction - A physico-chemical study

    Indian Academy of Sciences (India)

    N Nishad Fathima; R Saranya Devi; K B Rekha; Aruna Dhathathreyan

    2009-07-01

    Curcumin is a widely used therapeutic agent with a wide spectrum of biological and physiological applications like wound healing and interacts with the skin protein, collagen. This work reports the effect of curcumin on various physico-chemical properties of collagen. The results suggest that significant changes in viscosity and surface tension occur on collagen interacting with curcumin. Secondary structure analysis using circular dichroism shows that curcumin does not alter the triple helical structure of collagen. Increasing concentration of curcumin resulted in aggregation of the protein. Further, curcumin imparts high level of thermal stability to collagen with shrinkage temperature of collagen increasing from 60 to 90°C.

  18. [Studies on the chemical constitutens of Vicia amoena Fisch].

    Science.gov (United States)

    Wei, F; Yan, W M

    1997-10-01

    One new flavonoide was isolated from Vicia amoena Fisch. On the basis of spectral (UV, MS, NMR) and chemical reactions, it was elucidated to be kaempferol-3-O-beta-D-mannoside, named amoenin(A3). Moreover, five known compounds have been isolated and identified as quercetin, kaempferol, quercetin-3-O-alpha-L-rhamoside, quercetin-3-O-beta-D-glucoside, kaempferol-3, 7-O-alpha-L-dirhamoside. The total flavonoides showed significant effects on inducing hyperlipidemia and increasing micro-blood vessel elasticity. PMID:11596220

  19. A Rapid Compression Expansion Machine (RCEM) for studying chemical kinetics: Experimental principle and first applications

    CERN Document Server

    Werler, Marc; Maas, Ulrich

    2016-01-01

    A novel extension of a rapid compression machine (RCM), namely a Rapid Compression Expansion Machine (RCEM), is described and its use for studying chemical kinetics is demonstrated. Like conventional RCMs, the RCEM quickly compresses a fuel/air mixture by pushing a piston into a cylinder; the resulting high temperatures and pressures initiate chemical reactions. In addition, the machine can rapidly expand the compressed gas in a controlled way by pulling the piston outwards again. This freezes chemical activity after a pre-defined reaction duration, and therefore allows a convenient probe sampling and ex-situ gas analysis of stable species. The RCEM therefore is a promising instrument for studying chemical kinetics, including also partially reacted fuel/air mixtures. The setup of the RCEM, its experimental characteristics and its use for studying chemical reactions are outlined in detail. To allow comparisons of RCEM results with predictions of chemical reaction mechanisms, a simple numerical model of the RCE...

  20. On the study of nonlinear dynamics of complex chemical reaction systems

    Institute of Scientific and Technical Information of China (English)

    XIN; Houwen; HOU; Zhonghuai

    2006-01-01

    With ever-increasing attentions being paid to complex systems such as the life system, soft matter, and nano-systems, theoretical studies of non-equilibrium nonlinear problems involved in chemical dynamics are now of general interest. In this mini-review, we mainly give a brief introduction to some frontier topics in this field, namely, nonlinear state-state dynamics, nonlinear chemical dynamics on complex networks, and nonlinear dynamics in mesoscopic chemical reaction systems. Deep study of these topics will make great contribution to discovering new laws of chemical dynamics, to exploring new control methods of complex chemical processes, to figuring out the very roles of chemical processes in the life system, and to crosslinking the scientific study of chemistry, physics and biology.

  1. Collider Signatures of Goldstone Bosons

    CERN Document Server

    Cheung, Kingman; Yuan, Tzu-Chiang

    2014-01-01

    Recently Weinberg suggested that Goldstone bosons arising from the spontaneous breakdown of some global hidden symmetries can interact weakly in the early Universe and account for a fraction of the effective number of neutrino species N_{eff}, which has been reported persistently 2\\sigma away from its expected value of three. In this work, we study in some details a number of experimental constraints on this interesting idea based on the simplest possibility of a global U(1), as studied by Weinberg. We work out the decay branching ratios of the associated light scalar field \\sigma and suggest a possible collider signature at the Large Hadron Collider (LHC). In some corners of the parameter space, the scalar field \\sigma can decay into a pair of pions with a branching ratio of order 10% while the rest is mostly a pair of Goldstone bosons. The collider signature would be gluon fusion into the standard model Higgs boson gg -> H followed by H -> \\sigma \\sigma -> (\\pi\\pi) (\\alpha\\alpha) where \\alpha is the Goldsto...

  2. Studies on modelling of bubble driven flows in chemical reactors

    Energy Technology Data Exchange (ETDEWEB)

    Grevskott, Sverre

    1997-12-31

    Multiphase reactors are widely used in the process industry, especially in the petrochemical industry. They very often are characterized by very good thermal control and high heat transfer coefficients against heating and cooling surfaces. This thesis first reviews recent advances in bubble column modelling, focusing on the fundamental flow equations, drag forces, transversal forces and added mass forces. The mathematical equations for the bubble column reactor are developed, using an Eulerian description for the continuous and dispersed phase in tensor notation. Conservation equations for mass, momentum, energy and chemical species are given, and the k-{epsilon} and Rice-Geary models for turbulence are described. The different algebraic solvers used in the model are described, as are relaxation procedures. Simulation results are presented and compared with experimental values. Attention is focused on the modelling of void fractions and gas velocities in the column. The energy conservation equation has been included in the bubble column model in order to model temperature distributions in a heated reactor. The conservation equation of chemical species has been included to simulate absorption of CO{sub 2}. Simulated axial and radial mass fraction profiles for CO{sub 2} in the gas phase are compared with measured values. Simulations of the dynamic behaviour of the column are also presented. 189 refs., 124 figs., 1 tab.

  3. A microwave and quantum chemical study of allyltrifluorosilane

    Science.gov (United States)

    Møllendal, H.; Guirgis, G. A.

    2003-04-01

    The structural and conformational properties of allytrifluorsilane, H 2CCH-CH 2-SiF 3, have been explored by microwave (MW) spectroscopy and high-level ab initio and density functional theory quantum chemical calculations. The microwave spectrum was investigated in the 18-62 GHz spectral regions. The a-type R-branch transitions of one conformer were assigned for the ground as well as for 10 vibrationally excited states. The CC-C-Si chain of atoms in this rotamer takes an anti-clinal ('skew') conformation, with a dihedral angle calculated to be 111.6° from the syn-periplanar (0°) conformation. The question whether a CC-C-Si syn-periplanar conformer exists as a high-energy form in the gas phase remains open. In most of the quantum chemical calculations this conformation is predicted to be a transition state. However, in the most advanced calculations (B3LYP/aug-cc-pVTZ level of theory) the syn-periplanar conformer is predicted to be a stable rotamer that is calculated to be 6.5 kJ/mol higher in energy than the anti-clinal form. Since there is no indication in the MW spectrum for the presence of high-energy form(s), it is concluded that the anti-clinal conformer is at least 4 kJ/mol more stable than any other hypothetical rotamer.

  4. Quantum Chemical Study of the Thermochemical Properties of Organophosphorous Compounds.

    Science.gov (United States)

    Khalfa, A; Ferrari, M; Fournet, R; Sirjean, B; Verdier, L; Glaude, P A

    2015-10-22

    Organophosphorous compounds are involved in many toxic compounds such as fungicides, pesticides, or chemical warfare nerve agents. The understanding of the decomposition chemistry of these compounds in the environment is largely limited by the scarcity of thermochemical data. Because of the high toxicity of many of these molecules, experimental determination of their thermochemical properties is very difficult. In this work, standard gas-phase thermodynamic data, i.e., enthalpies of formation (ΔfH298°), standard entropies (S298°), and heat capacities (Cp°(T)), were determined using quantum chemical calculations and more specifically the CBS-QB3 composite method, which was found to be the best compromise between precision and calculation time among high accuracy composite methods. A large number of molecules was theoretically investigated, involving trivalent and pentavalent phosphorus atoms, and C, H, O, N, S, and F atoms. These data were used to propose 83 original groups, used in the semiempirical group contribution method proposed by Benson. Thanks to these latter group values, thermochemical properties of several nerve agents, common pesticides and herbicides have been evaluated. Bond dissociations energies (BDE), useful for the analysis the thermal stability of the compounds, were also determined in several molecules of interest. PMID:26434606

  5. Tracking and understanding the acoustic signature of fluido-fractures: a dual optical/micro-seismic study

    Science.gov (United States)

    Turkaya, Semih; Toussaint, Renaud; Kvalheim Eriksen, Fredrik; Zecevic, Megan; Daniel, Guillaume; Jørgen Måløy, Knut; Grude Flekkøy, Eirik

    2015-04-01

    The characterization and comprehension of irreversible rock deformation processes due to fluid flow is a challenging problem with numerous applications in many fields. This phenomenon has received an ever-increasing attention in Earth Science, Physics, with many applications in natural hazard understanding, mitigation or forecast (e.g. earthquakes, control the mechanical stability of rock and soil formations during the injection or extraction of fluids, landslides with hydrological control, volcanic eruptions), or in the industry, as CO2 sequestration. In this study, analogue models are developed (similar to the previous work of Johnsen[1] but in rectangular shape) to study the instabilities developing during motion of fluid in dense porous materials: fracturing, fingering, channelling… We study these complex fluid/solid mechanical systems using two imaging techniques: fast optical imaging and high frequency resolution of acoustic emissions. Additionally, we develop physical models rendering for the fluid mechanics (similar to the work of Niebling[2] but with injection of fluid) in the channels and the propagation of microseismic waves around the fracture. We then confront a numerical resolution of this physical system with the observed experimental system. The experimental setup consists in a rectangular Hele-Shaw cell with three closed boundaries and one semi-permeable boundary which enables the flow of the fluid but not the solid particles. During the experiments, the fluid is injected into the system with a constant injection pressure from the point opposite to the semi-permeable boundary. The fluid penetrates into the solid using the pore network. At the large enough injection pressures, the fluid also makes its way via creating channels, fractures to the semi-permeable boundary. During the experiments acoustic signals are recorded using different sensors then, those signals are compared and investigated further in both time and frequency domains

  6. On Constructing Certificateless Proxy Signature from Certificateless Signature

    Institute of Scientific and Technical Information of China (English)

    WAN Zhong-mei; LAI Xue-jia; WENG Jian; HONG Xuan; LONG Yu; JIA Wei-wei

    2008-01-01

    In proxy signature schemes,an original signer A delegates its signing capability to a proxy signer B,in such a way that B can sign message on behalf of A.The recipient of the final message verifies at the same time that B computes the signature and that A has delegated its signing capability to B.Recently many identity-based (ID-based) proxy signature schemes have been proposed,however,the problem of key escrow is inherent in this setting.Certificateless cryptography can overcome the key escrow problem.In this paper,we present a general security model for certificateless proxy signature scheme.Then,we give a method to construct a secure certificateless proxy scheme from a secure certificateless signature scheme,and prove that the security of the construction can be reduced to the security of the original certificateless signature scheme.

  7. Spatiotemporally dissociable neural signatures for generating and updating expectation over time in children: A High Density-ERP study.

    Science.gov (United States)

    Mento, Giovanni; Vallesi, Antonino

    2016-06-01

    Temporal orienting (TO) is the allocation of attentional resources in time based on the a priori generation of temporal expectancy of relevant stimuli as well as the a posteriori updating of this expectancy as a function of both sensory-based evidence and elapsing time. These processes rely on dissociable cognitive mechanisms and neural networks. Yet, although there is evidence that TO may be a core mechanism for cognitive functioning in childhood, the developmental spatiotemporal neural dynamics of this mechanism are little understood. In this study we employed a combined approach based on the application of distributed source reconstruction on a high spatial resolution ERP data array obtained from eighteen 8- to 12-year-old children completing a TO paradigm in which both the cue (Temporal vs. Neutral) and the SOA (Short vs. Long) were manipulated. Results show both cue (N1) and SOA (CNV, Omission Detection Potential and Anterior Anticipatory Index) ERP effects, which were associated with expectancy generation and updating, respectively. Only cue-related effects were correlated with age, as revealed by a reduction of the N1 delta effect with increasing age. Our data suggest that the neural correlates underlying TO are already established at least from 8 to 12 years of age. PMID:26946428

  8. Optical studies of SN 2009jf: A type Ib supernova with an extremely slow decline and aspherical signature

    CERN Document Server

    Sahu, D K; Anupama, G C; Nomoto, K

    2011-01-01

    Optical $UBVRI$ photometry and medium resolution spectroscopy of the type Ib supernova SN 2009jf, during the period $\\sim -15$ to +250days with respect to the $B$ maximum are reported. The light curves are broad, with an extremely slow decline. The early post-maximum decline rate in the $V$ band is similar to SN 2008D, however, the late phase decline rate is slower than other studied type Ib supernovae. With an absolute magnitude of $M_{V} = -17.96\\pm0.19$ magnitude at peak, SN 2009jf is a normally bright supernova. The peak bolometric luminosity and the energy deposition rate via $^{56}$Ni $\\rightarrow$ $^{56}$Co chain indicate that $\\sim {0.17}^{+0.03}_{-0.03}$ M$_{\\odot}$ of $^{56}$Ni was ejected during the explosion. He\\,I 5876 \\AA\\ line is clearly identified in the first spectrum of day $\\sim -15$, at a velocity of $\\sim 16000$ km sec$^{-1}$. The [O\\,I] 6300-6364 \\AA\\ line seen in the nebular spectrum has a multi-peaked and asymmetric emission profile, with the blue peak being stronger. The estimated flu...

  9. Vibrational signatures in the THz spectrum of 1,3-DNB: A first-principles and experimental study

    Science.gov (United States)

    Ahmed, Towfiq; Azad, Abul K.; Chellappa, Raja; Higginbotham-Duque, Amanda; Dattelbaum, Dana M.; Zhu, Jian-Xin; Moore, David; Graf, Matthias J.

    2016-05-01

    Understanding the fundamental processes of light-matter interaction is important for detection of explosives and other energetic materials, which are active in the infrared and terahertz (THz) region. We report a comprehensive study on electronic and vibrational lattice properties of structurally similar 1,3-dinitrobenzene (1,3-DNB) crystals through first-principles electronic structure calculations and THz spectroscopy measurements on polycrystalline samples. Starting from reported x-ray crystal structures, we use density-functional theory (DFT) with periodic boundary conditions to optimize the structures and perform linear response calculations of the vibrational properties at zero phonon momentum. The theoretically identified normal modes agree qualitatively with those obtained experimentally in a frequency range up to 2.5 THz and quantitatively at much higher frequencies. The latter frequencies are set by intra-molecular forces. Our results suggest that van der Waals dispersion forces need to be included to improve the agreement between theory and experiment in the THz region, which is dominated by intermolecular modes and sensitive to details in the DFT calculation. An improved comparison is needed to assess and distinguish between intra- and intermolecular vibrational modes characteristic of energetic materials.

  10. Cryptanalysis of the arbitrated quantum signature protocols

    CERN Document Server

    Gao, Fei; Guo, Fen-Zhuo; Wen, Qiao-Yan

    2011-01-01

    As a new model for signing quantum message, arbitrated quantum signature (AQS) has recently received a lot of attention. In this paper we study the cryptanalysis of previous AQS protocols from the aspects of forgery and disavowal. We show that in these protocols the receiver Bob can realize existential forgery of the sender's signature under known message attack. Bob can even achieve universal forgery when the protocols are used to sign a classical message. Furthermore, the sender Alice can successfully disavow any of her signatures by simple attack. The attack strategies are described in detail and some discussions about the potential improvements of the protocols are given. Finally we also present several interesting topics in future study on AQS protocols.

  11. Use of the LITEE Lorn Manufacturing Case Study in a Senior Chemical Engineering Unit Operations Laboratory

    Science.gov (United States)

    Abraham, Nithin Susan; Abulencia, James Patrick

    2011-01-01

    This study focuses on the effectiveness of incorporating the Laboratory for Innovative Technology and Engineering Education (LITEE) Lorn Manufacturing case into a senior level chemical engineering unit operations course at Manhattan College. The purpose of using the case study is to demonstrate the relevance of ethics to chemical engineering…

  12. Study on Physical Properties and Chemical Composition of Some Myanmar Gems

    International Nuclear Information System (INIS)

    Physical properties of some Myanmar gems were studied by using refractometer, dichroscope, polariscope, SG test, UV test and microscope. Then, chemical composition were investigated by XRF-technique. After that, gem identification, evaluation, colour improvement were studied according to these physical properties and chemical composition

  13. Signatures of nonthermal melting

    Directory of Open Access Journals (Sweden)

    Tobias Zier

    2015-09-01

    Full Text Available Intense ultrashort laser pulses can melt crystals in less than a picosecond but, in spite of over thirty years of active research, for many materials it is not known to what extent thermal and nonthermal microscopic processes cause this ultrafast phenomenon. Here, we perform ab-initio molecular-dynamics simulations of silicon on a laser-excited potential-energy surface, exclusively revealing nonthermal signatures of laser-induced melting. From our simulated atomic trajectories, we compute the decay of five structure factors and the time-dependent structure function. We demonstrate how these quantities provide criteria to distinguish predominantly nonthermal from thermal melting.

  14. CORRELATION STUDIES BETWEEN PHYSICO-CHEMICAL, CHEMICAL AND NUTRIENT UPTAKES OF PADDY IN PHOSPHORUS RICH VERTISOLS

    OpenAIRE

    V Siva Jyothi; T Giridhara Krishna; P.KAVITHA; Srinivasa Reddy, M.

    2014-01-01

    A field experiment was conducted in paddy having high soil available P vertisols under K.C. Canal ayacut at Regional Agricultural Research Station, Nandyal, Andhra Pradesh. The correlation studies revealed that there exist a positive strong correlation between agronomic characters at different stages with the yield. pH and EC was positively correlate with yield except pH at panicle initiation stage is non significantly correlate with yield. The available nitrogen at tillering (r= 0.446), pani...

  15. TREATMENT TANK CORROSION STUDIES FOR THE ENHANCED CHEMICAL CLEANING PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.

    2011-08-24

    Radioactive waste is stored in high level waste tanks on the Savannah River Site (SRS). Savannah River Remediation (SRR) is aggressively seeking to close the non-compliant Type I and II waste tanks. The removal of sludge (i.e., metal oxide) heels from the tank is the final stage in the waste removal process. The Enhanced Chemical Cleaning (ECC) process is being developed and investigated by SRR to aid in Savannah River Site (SRS) High-Level Waste (HLW) as an option for sludge heel removal. Corrosion rate data for carbon steel exposed to the ECC treatment tank environment was obtained to evaluate the degree of corrosion that occurs. These tests were also designed to determine the effect of various environmental variables such as temperature, agitation and sludge slurry type on the corrosion behavior of carbon steel. Coupon tests were performed to estimate the corrosion rate during the ECC process, as well as determine any susceptibility to localized corrosion. Electrochemical studies were performed to develop a better understanding of the corrosion mechanism. The tests were performed in 1 wt.% and 2.5 wt.% oxalic acid with HM and PUREX sludge simulants. The following results and conclusions were made based on this testing: (1) In 1 wt.% oxalic acid with a sludge simulant, carbon steel corroded at a rate of less than 25 mpy within the temperature and agitation levels of the test. No susceptibility to localized corrosion was observed. (2) In 2.5 wt.% oxalic acid with a sludge simulant, the carbon steel corrosion rates ranged between 15 and 88 mpy. The most severe corrosion was observed at 75 C in the HM/2.5 wt.% oxalic acid simulant. Pitting and general corrosion increased with the agitation level at this condition. No pitting and lower general corrosion rates were observed with the PUREX/2.5 wt.% oxalic acid simulant. The electrochemical and coupon tests both indicated that carbon steel is more susceptible to localized corrosion in the HM/oxalic acid environment than

  16. Adsorption study of copper (II) by chemically modified orange peel

    International Nuclear Information System (INIS)

    An adsorbent, the chemically modified orange peel, was prepared from hydrolysis of the grafted copolymer, which was synthesized by interaction of methyl acrylate with cross-linking orange peel. The presence of poly (acrylic acid) on the biomass surface was verified by infrared spectroscopy (IR), scanning electron microscopy (SEM) and thermogravimetry (TG). Total negative charge in the biomass surface and the zeta potentials were determined. The modified biomass was found to present high adsorption capacity and fast adsorption rate for Cu (II). From Langmuir isotherm, the adsorption capacity for Cu (II) was 289.0 mg g-1, which is about 6.5 times higher than that of the unmodified biomass. The kinetics for Cu (II) adsorption followed the pseudo-second-order kinetics. The adsorbent was used to remove Cu (II) from electroplating wastewater and was suitable for repeated use for more than four cycles.

  17. Exploring Signature Pedagogies in Undergraduate Leadership Education

    Science.gov (United States)

    Jenkins, Daniel M.

    2012-01-01

    This research explores the instructional strategies most frequently used by leadership educators who teach academic credit-bearing undergraduate leadership studies courses through a national survey and identifies signature pedagogies within the leadership discipline. Findings from this study suggest that class discussion--whether in the form of…

  18. Groundwater hydrology study of the Ames Chemical Disposal Site

    International Nuclear Information System (INIS)

    The Ames Laboratory Chemical Disposal Site is located in northwestern Ames, Iowa west of Squaw Creek. From 1957 to 1966, Ames Laboratory conducted research to develop processes to separate uranium and thorium from nuclear power fuel and to separate yttrium from neutron shielding sources. The wastes from these processes, which contained both hazardous and radiological components, were placed into nine burial pits. Metal drums, plywood boxes, and steel pails were used to store the wastes. Uranium was also burned on the ground surface of the site. Monitoring wells were placed around the waste burial pits. Groundwater testing in 1993 revealed elevated levels of Uranium 234, Uranium 238, beta and alpha radiation. The north side of the burial pit had elevated levels of volatile organic compounds. Samples in the East Ravine showed no volatile organics; however, they did contain elevated levels of radionuclides. These analytical results seem to indicate that the groundwater from the burial pit is flowing down hill and causing contamination in the East Ravine. Although there are many avenues for the contamination to spread, the focus of this project is to understand the hydrogeology of the East Ravine and to determine the path of groundwater flow down the East Ravine. The groundwater flow data along with other existing information will be used to assess the threat of chemical migration down the East Ravine and eventually off-site. The primary objectives of the project were as follows: define the geology of the East Ravine; conduct slug tests to determine the hydraulic conductivity of both oxidized and unoxidized till; develop a three-dimensional mathematical model using ModIME and MODFLOW to simulate groundwater flow in the East Ravine

  19. Observational signatures of binary supermassive black holes

    International Nuclear Information System (INIS)

    Observations indicate that most massive galaxies contain a supermassive black hole, and theoretical studies suggest that when such galaxies have a major merger, the central black holes will form a binary and eventually coalesce. Here we discuss two spectral signatures of such binaries that may help distinguish them from ordinary active galactic nuclei. These signatures are expected when the mass ratio between the holes is not extreme and the system is fed by a circumbinary disk. One such signature is a notch in the thermal continuum that has been predicted by other authors; we point out that it should be accompanied by a spectral revival at shorter wavelengths and also discuss its dependence on binary properties such as mass, mass ratio, and separation. In particular, we note that the wavelength λ n at which the notch occurs depends on these three parameters in such a way as to make the number of systems displaying these notches ∝λn16/3; longer wavelength searches are therefore strongly favored. A second signature, first discussed here, is hard X-ray emission with a Wien-like spectrum at a characteristic temperature ∼100 keV produced by Compton cooling of the shock generated when streams from the circumbinary disk hit the accretion disks around the individual black holes. We investigate the observability of both signatures. The hard X-ray signal may be particularly valuable as it can provide an indicator of black hole merger a few decades in advance of the event.

  20. Signature splitting in 135Pr

    International Nuclear Information System (INIS)

    In-beam spectroscopic study of 135Pr was made using 91 MeV 120Sn(19F,4n) reaction. A strong negative parity proton band based on the h/sub 11/2-/ 1/2[550] configuration with α = -1/2 was observed. Possibly α = +1/2 unfavored band is observed. Also two positive parity proton bands are observed most likely based on the g/sub 7/2+/ 5/2[413] configurations with α = +-1/2. In all cases (except for the (π,α) = (-,+1/2) band) the backbending is caused by alignment of two h/sub 11/2-/ 9/2[514] quasi-neutrons. For the strongly decoupled π(-) bands the observed signature splitting decreases with increasing rotational frequency. The signature splitting of the positive parity bands increases with rotational frequency and then inverts above the backbending. This is interpreted to be caused by the quasi-neutrons, which drive the γ-deformation to the negative values. 18 refs., 6 figs

  1. Risk management and governance of chemicals in articles. Case study textiles

    OpenAIRE

    Assmuth, Timo; HÀkkinen, Piia; Heiskanen, Jaana; Kautto, Petrus; Lindh, PÀivi; Mattila, Tuomas; Mehtonen, Jukka; Saarinen, Kristiina

    2011-01-01

    Chemicals and textiles both arouse great interest and emotions. The risks from chemicals in textiles however have been paid little attention, both from the perspective of human health and even more with regard to the environment. The present case study analyzes risks as well as benefits and other impacts from chemicals associated with consumer textiles, as well as management and governance approaches to deal with the multi-faceted problems involved, in the broader context of product and chemi...

  2. Signatures of AGN feedback

    Science.gov (United States)

    Wylezalek, D.; Zakamska, N.

    2016-06-01

    Feedback from active galactic nuclei (AGN) is widely considered to be the main driver in regulating the growth of massive galaxies. It operates by either heating or driving the gas that would otherwise be available for star formation out of the galaxy, preventing further increase in stellar mass. Observational proof for this scenario has, however, been hard to come by. We have assembled a large sample of 133 radio-quiet type-2 and red AGN at 0.1importantly, we find a negative correlation between W_{90} and sSFR in the AGN hosts with the highest star formation rates, i.e., with the highest gas content. This relationship implies that AGN with strong outflow signatures are hosted in galaxies that are more `quenched' considering their stellar mass than galaxies with weaker outflow signatures. This correlation is only seen in AGN host galaxies with SFR >100 M_{⊙} yr^{-1} where presumably the coupling of the AGN-driven wind to the gas is strongest. This observation is consistent with the AGN having a net suppression, or `negative' impact, through feedback on the galaxies' star formation history.

  3. Clustering signatures classify directed networks

    Science.gov (United States)

    Ahnert, S. E.; Fink, T. M. A.

    2008-09-01

    We use a clustering signature, based on a recently introduced generalization of the clustering coefficient to directed networks, to analyze 16 directed real-world networks of five different types: social networks, genetic transcription networks, word adjacency networks, food webs, and electric circuits. We show that these five classes of networks are cleanly separated in the space of clustering signatures due to the statistical properties of their local neighborhoods, demonstrating the usefulness of clustering signatures as a classifier of directed networks.

  4. Expressiveness considerations of XML signatures

    DEFF Research Database (Denmark)

    Jensen, Meiko; Meyer, Christopher

    2011-01-01

    more and more challenging. In this paper, we investigate this issue, describing how an attacker can still interfere with Web Services communication even in the presence of XML Signatures. Additionally, we discuss the interrelation of XML Signatures and XML Encryption, focussing on their security......XML Signatures are used to protect XML-based Web Service communication against a broad range of attacks related to man-in-the-middle scenarios. However, due to the complexity of the Web Services specification landscape, the task of applying XML Signatures in a robust and reliable manner becomes...

  5. Plasma signatures of radial field power dropouts

    International Nuclear Information System (INIS)

    A class of small scale structures, with a near-radial magnetic field and a drop in magnetic field fluctuation power, have recently been identified in the polar solar wind. An earlier study of 24 events, each lasting for 6 hours or more, identified no clear plasma signature. In an extension of that work, radial intervals lasting for 4 hours or more (89 in total), have been used to search for a statistically significant plasma signature. It was found that, despite considerable variations between intervals, there was a small but significant drop, on average, in plasma temperature, density and β during these events. copyright 1999 American Institute of Physics

  6. Plasma Signatures of Radial Field Power Dropouts

    International Nuclear Information System (INIS)

    A class of small scale structures, with a near-radial magnetic field and a drop in magnetic field fluctuation power, have recently been identified in the polar solar wind. An earlier study of 24 events, each lasting for 6 hours or more, identified no clear plasma signature. In an extension of that work, radial intervals lasting for 4 hours or more (89 in total), have been used to search for a statistically significant plasma signature. It was found that, despite considerable variations between intervals, there was a small but significant drop, on average, in plasma temperature, density and β during these events

  7. Chemical modification studies of the streptokinase-plasminogen interaction

    International Nuclear Information System (INIS)

    The streptokinase (SK) interaction with human plasminogen (Pg) was investigated by differential chemical modification. In separate experiments, available lysine residues in both free streptokinase and streptokinase in complex with Pg were trace labeled by reaction with high specific activity [3H]-acetic anhydride at a reagent-to-lysine molar ratio of 0.5%. The [3H]-acetyl-SK from the complex was reisolated. Both the free and complex forms of 3H-acetyl-SK were then each mixed with uniformly and quantitatively modified [14C]-acetyl-SK in a 3H/14C isotopic ratio of ten-to-one. Each of the SK forms was fragmented by reaction with CNBr. These CNBr fragments, which were purified by Sephadex G-75 chromatography, were further cleaved by proteases to produce peptides containing a minimum number of lysines. After the isolation of peptides by reversed-phase HPLC, the 3H/14C ratios of lysines were individually determined. By comparison of the 3H/14C ratio's in the free-SK and complex-SK it was found that the majority of lysines did not change its reactivities in free or complex forms. However, several lysines were relatively unreactive in the SK complexed with Pg as compared to that in free SK. This suggests that these residues are either in the complex binding interface or they were less reactive as a result of conformational change induced by complex formation

  8. Study of Chemical Decontamination Process for CRUD Removal

    International Nuclear Information System (INIS)

    Chalk River Unidentified Deposit (CRUD) is a technical term in nuclear engineering which is an accumulated material on external fuel rod cladding surfaces in nuclear power plants. It is a corrosion product which is composed of either dissolved ions or solid particles such as Ni, Fe and Co. It consists mainly of NiO and NiFe2O4. It can affect to reduce fuel lifetime, degrade heat transfer to the coolant, and threaten human health and environment. Therefore, decontamination process is essential for reducing occupational exposures, limiting potential releases and uptakes of radioactive materials, allowing the reuse of components, and facilitating waste management process. In this paper, we have conducted the synthesis of Cobalt ferrite as power foam to use for decontamination process. In dissolution test of Co ferrite and Ni ferrite, oxalic acid shows the most effective chemical decontamination reagent to remove the contaminants. Generally, the dissolved amount of cobalt and nickel increases at low pH condition and as the temperature goes higher, dissolved amount of cobalt and iron are much higher

  9. Study of Chemical Decontamination Process for CRUD Removal

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Seongsik; Kim, Won-Seok; Kim, Jungjin; Um, Wooyong [POSTECH, Pohang (Korea, Republic of)

    2015-05-15

    Chalk River Unidentified Deposit (CRUD) is a technical term in nuclear engineering which is an accumulated material on external fuel rod cladding surfaces in nuclear power plants. It is a corrosion product which is composed of either dissolved ions or solid particles such as Ni, Fe and Co. It consists mainly of NiO and NiFe{sub 2}O{sub 4}. It can affect to reduce fuel lifetime, degrade heat transfer to the coolant, and threaten human health and environment. Therefore, decontamination process is essential for reducing occupational exposures, limiting potential releases and uptakes of radioactive materials, allowing the reuse of components, and facilitating waste management process. In this paper, we have conducted the synthesis of Cobalt ferrite as power foam to use for decontamination process. In dissolution test of Co ferrite and Ni ferrite, oxalic acid shows the most effective chemical decontamination reagent to remove the contaminants. Generally, the dissolved amount of cobalt and nickel increases at low pH condition and as the temperature goes higher, dissolved amount of cobalt and iron are much higher.

  10. Chemical and environmental isotope study of precipitation in Syria

    International Nuclear Information System (INIS)

    Waters from a network of rainfall collection covering mine meteorological stations distributed mainly in the western part of Syria have been assayed using chemical and environmental isotope techniques for a period of 5 months from Dec. 1989 to Apr. 1990. The chemistry of rain waters falling over the mountainous stations shows a low solute concentration (20-105 mg 1-1) compared with those falling over the coastal and anterior stations (50-210 mg 1-1). The rain waters was generally characterized by a high deuterium excess (d=19%) compared with that of typical global meteoric waters (d=10%). The estimated deuterium excess is lower than that for the eastern Mediterranean meteoric waters (d=22%). The altitude effect is shown up by a depletion of heavy stable isotopes of about - 0.23% and -1.65% per 100 m elevation of δ 18O and δD, respectively. The spatial distribution pattern of tritium contents shows a gradual build up with increasing distance from the Syrian coast. The weighted mean tritium content in rain waters falling over the country is estimated to amount to 9.5 tritium units (TU) during the period of observation. (author)

  11. Evidence for excited-state intramolecular proton transfer in 4-chlorosalicylic acid from combined experimental and computational studies: Quantum chemical treatment of the intramolecular hydrogen bonding interaction

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Bijan Kumar [Department of Chemistry, University of Calcutta, 92 Acharya Prafulla Chandra Road, Calcutta 700009 (India); Guchhait, Nikhil, E-mail: nikhil.guchhait@rediffmail.com [Department of Chemistry, University of Calcutta, 92 Acharya Prafulla Chandra Road, Calcutta 700009 (India)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer Experimental and computational studies on the photophysics of 4-chlorosalicylic acid. Black-Right-Pointing-Pointer Spectroscopically established ESIPT reaction substantiated by theoretical calculation. Black-Right-Pointing-Pointer Quantum chemical treatment of IMHB unveils strength, nature and directional nature. Black-Right-Pointing-Pointer Superiority of quantum chemical treatment of H-bond over geometric criteria. Black-Right-Pointing-Pointer Role of H-bond as a modulator of aromaticity. -- Abstract: The photophysical study of a pharmaceutically important chlorine substituted derivative of salicylic acid viz., 4-chlorosalicylic acid (4ClSA) has been carried out by steady-state absorption, emission and time-resolved emission spectroscopy. A large Stokes shifted emission band with negligible solvent polarity dependence marks the spectroscopic signature of excited-state intramolecular proton transfer (ESIPT) reaction in 4ClSA. Theoretical calculation by ab initio and Density Functional Theory methods yields results consistent with experimental findings. Theoretical potential energy surfaces predict the occurrence of proton transfer in S{sub 1}-state. Geometrical and energetic criteria, Atoms-In-Molecule topological parameters, Natural Bond Orbital population analysis have been exploited to evaluate the intramolecular hydrogen bond (IMHB) interaction and to explore its directional nature. The inter-correlation between aromaticity and resonance assisted H-bond is also discussed in this context. Our results unveil that the quantum chemical treatment is a more accurate tool to assess hydrogen bonding interaction in comparison to geometrical criteria.

  12. Experimental study of chemical embolus therapy combined with radiotherapy for VX2 bone tumors

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Hiroshi; Mochizuki, Kazuo; Ishii, Yoshiaki [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine

    2000-12-01

    We conducted an experimental study, using a combination of coarse crystal cisplatin and radiotherapy for bone tumors, to evaluate the possibility of the clinical application of chemical embolus therapy in the field of orthopedic surgery. Experimental femoral bone tumors were produced, in rabbits, using VX2 carcinoma. The rabbits were allocated to five groups: untreated control, embolus, chemical embolus, irradiation alone, and chemical embolus and irradiation combination. These therapies were evaluated comparatively, in terms of local antitumor effects (including body weight, X-ray findings, angiography, and histopathology) and in terms of inhibition of pulmonary metastasis. Local antitumor effects, as evaluated by all parameters, except for body weight, were significantly greater for the chemical and irradiation combination group than for the chemical embolus, irradiation alone, untreated control, and embolus groups. There was no significant difference in the inhibition of pulmonary metastasis among the chemical embolus and irradiation combination, chemical embolus, and irradiation alone groups. These findings demonstrated the synergistic effect of the combination of chemical embolus therapy and radiotherapy. In this study, however, no significant difference was found between the chemical embolus therapy alone and the combination therapy groups in the inhibitory effect on pulmonary tumor metastasis, suggesting the need to conduct combination therapy repeatedly in the clinical setting. (author)

  13. [Advances in studies on chemical constituents and biological activities of Desmodium species].

    Science.gov (United States)

    Liu, Chao; Wu, Ying; Zhang, Qian-Jun; Kang, Wen-Yi; Zhang, Long; Zhou, Qing-Di

    2013-12-01

    The chemical constituents isolated from Desmodium species (Leguminosae) included terpenoids, flavonoids, steroids, alkaloids compounds. Modem pharmacological studies have showed that the Desmodium species have antioxidant, antibacterial, anti-inflammatory, hepatoprotective, diuretic, antipyretic, analgesic and choleretic activity. This article mainly has reviewed the research advances of chemical constituents and biological activities of Desmodium species since 2003. PMID:24791478

  14. Raman spectroscopic studies of chemical speciation in calcium chloride melts

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, Charles F.; Lavender, Curt A.

    2005-02-01

    Raman spectroscopy was applied to CaCl2 melts at 900 degrees C under both non-electrolyzed and electrolyzed conditions. The later used titania cathodes supplied by TIMET, Inc. and graphite anodes. Use of pulse-gating to collect the Raman spectra successfully eliminated any interference from black-body radiation and other stray light. The spectrum of molten CaCl2 exhibited no distinct, resolvable bands that could be correlated with a calcium chloride complex similar to MgCl42- in MgCl2 melts. Rather, the low frequency region of the spectrum was dominated by a broad “tail” arising from collective oscillations of both charge and mass in the molten salt “network.” Additions of both CaO and Ca at concentrations of a percent or two resulted in no new features in the spectra. Addition of CO2, both chemically and via electrolysis at concentrations dictated by stability and solubility at 900 degrees C and 1 bar pressure, also produced no new bands that could be correlated with either dissolved CO2 or the carbonate ion. These results indicated that Raman spectroscopy, at least under the conditions evaluated in the research, was not well suited for following the reactions and coordination chemistry of calcium ions, nor species such as dissolved metallic Ca and CO2 that are suspected to impact current efficiency in titanium electrolysis cells using molten CaCl2. Raman spectra of TIMET titania electrodes were successfully obtained as a function of temperature up to 900 degrees C, both in air and in-situ in CaCl2 melts. However, spectra of these electrodes could only be obtained when the material was in the unreduced state. When reduced, either with hydrogen or within an electrolysis cell, the resulting electrodes exhibited no measurable Raman bands under the conditions used in this work.

  15. Single-collision studies of energy transfer and chemical reaction

    Energy Technology Data Exchange (ETDEWEB)

    Valentini, J.J. [Columbia Univ., New York, NY (United States)

    1993-12-01

    The research focus in this group is state-to-state dynamics of reaction and energy transfer in collisions of free radicals such as H, OH, and CH{sub 3} with H{sub 2}, alkanes, alcohols and other hydrogen-containing molecules. The motivation for the work is the desire to provide a detailed understanding of the chemical dynamics of prototype reactions that are important in the production and utilization of energy sources, most importantly in combustion. The work is primarily experimental, but with an important and growing theoretical/computational component. The focus of this research program is now on reactions in which at least one of the reactants and one of the products is polyatomic. The objective is to determine how the high dimensionality of the reactants and products differentiates such reactions from atom + diatom reactions of the same kinematics and energetics. The experiments use highly time-resolved laser spectroscopic methods to prepare reactant states and analyze the states of the products on a single-collision time scale. The primary spectroscopic tool for product state analysis is coherent anti-Stokes Raman scattering (CARS) spectroscopy. CARS is used because of its generality and because the extraction of quantum state populations from CARS spectra is straightforward. The combination of the generality and easy analysis of CARS makes possible absolute cross section measurements (both state-to-state and total), a particularly valuable capability for characterizing reactive and inelastic collisions. Reactant free radicals are produced by laser photolysis of appropriate precursors. For reactant vibrational excitation stimulated Raman techniques are being developed and implemented.

  16. Chemical and environmental isotopes study of precipitation in Syria

    International Nuclear Information System (INIS)

    Chemical and isotopic compositions of monthly precipitation were monitored at 12 stations distributed over the entire region in Syria for a period of 4 years from December 1999 to April 2003. Amount of precipitation and mean air temperature of rain monthly were also recorded. The conductivity of rain waters varies between 35 μ/cm in the mountainous stations and 336 μ/cm at Deir Az-Zor station. Excepted Tartous station, the mean value of Cl in the rainfall in all station is 3.8 mg/l. The seasonal variations in δ18O are smaller at west stations than to the east stations due to low seasonal temperature variations. All stations are characterized by water lines with slopes significantly lower than GMWL, except Bloudan, suggesting the influence of local factors on the isotopic composition of the precipitation. d-excess values decrease from 19% in the western part to 13% in the eastern part of Syria, indicating the influence of the precipitation generated by the air masses coming from the Mediterranean Sea over Syria. A reliable altitude effect represent by depletion of heavy stable isotopes of about -0.21, and -1.47, per 100 m elevation of 18O and δ2H, respectively. Monthly tritium activity and seasonal variations pattern are low in the west stations than at the east stations. The weighted mean tritium values are between 3 to 9 TU during 2000-2003, and it is increasing with distance from the Syrian coast by 1 TU /100 Km. (author)

  17. SUSY with ATLAS Leptonic Signatures, Coannihilation Region

    CERN Document Server

    Comune, G

    2004-01-01

    In this work we present an initial study on how leptonic signatures can be used at ATLAS to constrain SUSY particle masses combinations for the first time in the so called "coannihilation region''. The analysis is carried out in the framework of mSUGRA constrained SUSY model using fast detector simulation and reconstruction exploiting an invariant mass endpoint technique.

  18. The Pedagogic Signature of Special Needs Education

    Science.gov (United States)

    Weiß, Sabine; Kollmannsberger, Markus; Lerche, Thomas; Oubaid, Viktor; Kiel, Ewald

    2014-01-01

    The goal of the following study is to identify a pedagogic signature, according to LS Shulman, for working with students who have special educational needs. Special educational needs are defined as significant limitations in personal development and learning which require particular educational measures beyond regular education. The development of…

  19. Chemical and Spectroscopic Studies of Carotenoids and Related Compounds

    OpenAIRE

    Lutnæs, Bjart Frode

    2004-01-01

    Structure elucidation of charge delocalised carotenoid mono- and dications by NMR and VIS/NIR spectroscopy. Studies of the nucleophilic reactions of these cations. Studies of the β,β-carotene-iodine complex. Isolation and anmalysis of new carotenoid glucoside esters from extremophilic bacteria.

  20. PROXY BLIND SIGNATURE BASED ON ECDLP

    Directory of Open Access Journals (Sweden)

    SATARUPA PRADHAN,

    2011-03-01

    Full Text Available Proxy blind signature combines the properties of both proxy signature and blind signature. In a proxy signature scheme, a signer delegates his signing power to a proxy, who signs a message on behalf of the original signer. In a blind signature scheme, the signer cannot link the relationship between the blind message and the signature of the chosen message. Therefore, it is very suitable for electronic commerceapplication. In this paper, a proxy blind signature scheme based on ECDLP (Elliptic Curve Discrete Logarithm Problem has been proposed, which satisfy the security properties of both the blind signature and the proxy signature. Analysis shows that our scheme is secure and efficient.

  1. Carbon, Energy and Water Footprint of threeAkzoNobel Internal Sizing Chemicals : A Cradle to Gate LCA related study

    OpenAIRE

    Triantou, Adamantia-Dimitra

    2009-01-01

    Functional chemicals are used in paper production to enhance specific characteristics in the final paper product. One functional chemicals category is internal sizing chemicals which are used to create liquid resistance hydrophobicity in the paper, at the wet end of the production process. This thesis report calculated the environmental burdens of three internal sizing chemicals produced by Eka Chemicals, a business unit of AkzoNobel. The three chemicals under study are a specific product of ...

  2. The topographic signature of anthropogenic geomorphic processes

    Science.gov (United States)

    Tarolli, P.; Sofia, G.

    2014-12-01

    Within an abiotic-dominated context, geomorphologic patterns and dynamics are single expressions of trade-offs between the physical resistance forces, and the mechanical and chemical forces related to climate and erosion. Recently, however, it has become essential for the geomorphological community to take into account also biota as a fundamental geomorphologic agent acting from local to regional scales. However, while there is a recent flourishing literature about the impacts of vegetation on geomorphic processes, the study of anthropogenic pressure on geomorphology is still at its early stages. Humans are indeed among the most prominent geomorphic agents, redistributing land surface, and causing drastic changes to the geomorphic organization of the landscape (e.g. intensive agriculture, urbanization), with direct consequences on land degradation and watershed response. The reconstruction or identification of artificial or anthropogenic topographies, therefore, provides a mechanism for quantifying anthropogenic changes to the landscape systems in the context of the Anthropocene epoch. High-resolution topographic data derived from the recent remote sensing technologies (e.g. lidar, SAR, SfM), offer now new opportunities to recognize better understand geomorphic processes from topographic signatures, especially in engineered landscapes where the direct anthropic alteration of processes is significant. It is possible indeed to better recognize human-induced geomorphic and anthropogenic features (e.g. road networks, agricultural terraces), and the connected erosion. The study presented here may allow improved understanding and targeted mitigation of the processes driving geomorphic changes during urban development and help guide future research directions for development-based watershed studies. Human society is deeply affecting the environment with consequences on the landscape. It is therefore fundamental to establish greater management control over the Earth

  3. Signatures de l'invisible

    CERN Multimedia

    CERN Press Office. Geneva

    2000-01-01

    "Signatures of the Invisible" is an unique collaboration between contemporary artists and contemporary physicists which has the potential to help redefine the relationship between science and art. "Signatures of the Invisible" is jointly organised by the London Institute - the world's largest college of art and design and CERN*, the world's leading particle physics laboratory. 12 leading visual artists:

  4. Sequential chemical extraction of heavy metals in a study of the chemical alteration of mine tailings at Ticapampa (Huaraz, Peru)

    International Nuclear Information System (INIS)

    The upper reaches of the Rio Santa (Huaraz, Peru) are highly affected by the mining activities of generally small and very small mining companies located in two specific areas, Cordillera Blanca, and Cordillera Negra, with the largest mining claims located in the districts of Recuay and Ticapampa. To assess the mobility and bioavailability of heavy metals in the abandoned tailings pond belonging to the Alianza mining company in the district of Ticapampa, and to identify the fractions to which they are associated we applied a sequential chemical extraction. The results were compared with studies into their mineralogical characterization, a quantitative chemical analysis and a determination of potential acidity and potential neutralization by the ABA (acid-base accounting) method applied to samples of tailings. The sequential extraction procedure confirmed the mode of general alteration observed in the area through mineralogical studies: a relatively easy mobility of Pb, and Cd, and considerable immobility with regard to Ag, Cr and Co, as well as an intermediate mobility of Cu, Zn, and As. Significant cadmium and lead contents found in the most mobile fractions of the tailings may represent an environmental threat, bearing in mind the toxic nature of these elements. Despite the low mobility of arsenic, the total quantities of this element are so high that the waters of the Rio Santa are being affected. (Author) 22 refs.

  5. Chemical Risk Evaluation: A Case Study in an Automotive Air Conditioner Production Facility

    Directory of Open Access Journals (Sweden)

    Tengku Hanidza T.I.

    2010-01-01

    Full Text Available There has been limited knowledge on worker’s exposure to chemicals used in the automotive industries. The purpose of this study is to assess chemical risk and to determine the adequacy of the existing control measures to reduce chemical exposure. A cross sectional survey was conducted in a factory involving installation and servicing of automotive air conditioner units. Qualitative exposure assessment was carried out following the Malaysian Chemical Health Risk Assessment Manual (CHRA. There were 180 employees, 156 workers worked in the production line, which constitutes six work units Tube fin pressed, Brazing, Welding, Final assembly, Piping and Kit II. From the chemical risk evaluation for each work unit, 26 chemical compounds were used. Most of the chemicals were irritants (eye and skin and some were asphyxiants and sensitizers. Based on the work assignment, 93 out of 180 (51.67% of the workers were exposed to chemicals. The highest numbers of workers exposed to chemicals were from the Brazing section (22.22% while the Final Assembly section was the lowest (1.67%. Health survey among the workers showed occurrence of eye irritation, skin irritation, and respiratory irritation, symptoms usually associated with chemical exposure. Using a risk rating matrix, several work process were identified as having ‘significant risk’. For these areas, the workers are at risk of adverse health effects since chemical exposure is not adequately controlled. This study recommends corrective actions be taken in order to control the level of exposure and to provide a safe work environment for workers.

  6. Synthesis and analysis in studies of chemical evolution

    Science.gov (United States)

    Ponnamperuma, C.; Hobish, M. K.; Kobayashi, K.; Hua, L. L.; Senaratne, N.

    1986-01-01

    Studies of the various processes that may have given rise to life on the Earth have demonstrated the appropriateness of an approach that makes use of analysis and synthesis. Analysis of extraterrestrial samples in the form of meteorites has demonstrated the presence of several precursors of biomolecules, most notably a full suite of nucleic acid bases and nucleotides of biological significance. These species were determined after exhaustive extraction of the sample and subsequent analysis using HPLC, GC, MS, and GC-MS. Procedural blanks indicate that these molecules are likely not the result of contamination during the extraction and analysis process. Similar species were found as products of spark discharge experiments in atmospheres thought to mimic primitive Earth conditions. These results indicate that the basic chemistry underlying these syntheses is common, and that life may not be unique to the Earth. Studies underway in the laboratory make use of proton nuclear magnetic resonance spectroscopy as a probe to assess associations between selected amino acids and any of several nucleotides comprising their genetic code and genetic anticode sequences. These studies demonstrate a clear selectivity by the anticode sequences, thus confirming the hydrophobicity studies performed by Lacey et al. These studies further support the contention that life is likely a natural result of the physics and chemistry of the universe.

  7. Conformational study of aromatic ketones: chemical shift reagents: uranium chelates

    International Nuclear Information System (INIS)

    A series of benzophenones, 2-benzoyl thiophenes and 2-benzoyl pyridines, all substituted at the benzene ring by an amino acid chain, have been synthesised with the object of examining to what extent the site of the aminoacid chain and the site and nature of the other substituents modify the electronic structure of the molecule and the orientation of each ring with respect to the plane of the carbonyl group. In the second part a study of paramagnetic cations, in particular of uranium, which is able to form stable chelates with beta-diketones was carried out to study their complexing power. The chelates studied are the (hexafluoropentanedionate)4U, the (heptafluorodimethyloctanedionate)4U and the (trifluorophenylbutanedionate)4U

  8. CHEMICAL, MICROBIOLOGICAL AND COMPARATIVE FERMENTATION STUDIES ON DASAMULARISHTA

    OpenAIRE

    Alam, Muzaffer; Dasan, K. K. S.; Rukmani, B.; Purushothaman, K. K.

    1984-01-01

    Dasamularista was prepared as per the national formulary to study the effect of container on the production of alcohol and the presence of microorganisms during the process of fermentation. Citraka (Plumbago rosea Linn.) which was one of the ingredient in the drug and subjected to “Sodhana” was also studied. The Citraka was impoverished by 50% with respect to plumbagin as a result of sodhana-purification. The drug prepared in glass vessel showed higher amount of alcohol than the earthen pot p...

  9. Spectroscopic characterization of nitroaromatic landmine signature explosives

    Science.gov (United States)

    Hernandez-Rivera, Samuel P.; Manrique-Bastidas, Cesar A.; Blanco, Alejandro; Primera, Oliva M.; Pacheco, Leonardo C.; Castillo-Chara, Jairo; Castro, Miguel E.; Mina, Nairmen

    2004-09-01

    TNT and DNT are important explosives used as base charges of landmines and other explosive devices. They are often combined with RDX in specific explosive formulations. Their detection in vapor phase as well as in soil in contact with the explosives is important in landmine detection technology. The spectroscopic signatures of nitroaromatic compounds in neat forms: crystals, droplets, and recrystallized samples were determined by Raman Microspectroscopy (RS), Fourier Transform Infrared Microscopy (FTIR) and Fiber Optics Coupled - Fourier Transform Infrared Spectroscopy (FOC-FTIR) using a grazing angle (GA) probe. TNT exhibits a series of characteristic bands: vibrational signatures, which allow its detection in soil. The spectroscopic signature of neat TNT is dominated by strong bands about 1380 and 2970 cm-1. The intensity and position of these bands were found remarkably different in soil samples spiked with TNT. The 1380 cm-1 band is split into a number of bands in that region. The 2970 cm-1 band is reduced in intensity and new bands are observed about 2880 cm-1. The results are consistent with a different chemical environment of TNT in soil as compared to neat TNT. Interactions were found to be dependent on the physical source of the explosive. In the case of DNT-sand interactions, shifts in vibrational frequencies of the explosives as well as the substrates were found.

  10. Analysis of dinucleotide signatures in HIV-1 subtype B genomes

    Indian Academy of Sciences (India)

    Aridaman Pandit; Jyothirmayi Vadlamudi; Somdatta Sinha

    2013-12-01

    Dinucleotide usage is known to vary in the genomes of organisms. The dinucleotide usage profiles or genome signatures are similar for sequence samples taken from the same genome, but are different for taxonomically distant species. This concept of genome signatures has been used to study several organisms including viruses, to elucidate the signatures of evolutionary processes at the genome level. Genome signatures assume greater importance in the case of host–pathogen interactions, where molecular interactions between the two species take place continuously, and can influence their genomic composition. In this study, analyses of whole genome sequences of the HIV-1 subtype B, a retrovirus that caused global pandemic of AIDS, have been carried out to analyse the variation in genome signatures of the virus from 1983 to 2007.We show statistically significant temporal variations in some dinucleotide patterns highlighting the selective evolution of the dinucleotide profiles of HIV-1 subtype B, possibly a consequence of host specific selection.

  11. Theoretical studies of the dynamics of chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, A.F. [Argonne National Laboratory, IL (United States)

    1993-12-01

    Recent research effort has focussed on several reactions pertinent to combustion. The formation of the formyl radical from atomic hydrogen and carbon monoxide, recombination of alkyl radicals and halo-alkyl radicals with halogen atoms, and the thermal dissociation of hydrogen cyanide and acetylene have been studied by modeling. In addition, the inelastic collisions of NCO with helium have been investigated.

  12. A Chemical and Crystallographic Study of Carbamyl-Chymotrypsin A

    NARCIS (Netherlands)

    Robillard, George T.; Powers, James C.; Wilcox, Philip E.

    1972-01-01

    The reaction of p-nitrophenyl cyanate with chymotrypsinogen A and chymotrypsin A has been studied to determine the potential of this reagent in the field of enzyme modifications. These experiments have shown that p-nitrophenyl [14C]cyanate can react at specific loci on the enzyme under mild conditio

  13. Theoretical Studies in Chemical Kinetics - Annual Report, 1970.

    Science.gov (United States)

    Karplus, Martin

    1970-10-01

    The research performed includes (a) Alkali-Halide, Alkali-Halide (MX, M’X’) Exchange Reactions; (b) Inversion Problem; (c) Quantum Mechanics of Scattering Processes, (d) Transition State Analysis of Classical Trajectories, (e) Differential Cross Sections from Classical Trajectories; and (f) Other Studies.

  14. Chemical Study of the Essential Oil of Mutisia Friesiana

    OpenAIRE

    de la Fuente, J.; C. I. Viturro

    2000-01-01

    The composition of essential oil of Mutisia friesiana (Asteracae) was studied. The oil is a complex system in which 127 compounds were identified. The major components are monoterpenes: b-phellandrene, (Z)-β-ocimene, α and β-pinene and sabinene.

  15. Spatio-Temporal Gene Expression Profiling during In Vivo Early Ovarian Folliculogenesis: Integrated Transcriptomic Study and Molecular Signature of Early Follicular Growth.

    Directory of Open Access Journals (Sweden)

    Agnes Bonnet

    Full Text Available The successful achievement of early ovarian folliculogenesis is important for fertility and reproductive life span. This complex biological process requires the appropriate expression of numerous genes at each developmental stage, in each follicular compartment. Relatively little is known at present about the molecular mechanisms that drive this process, and most gene expression studies have been performed in rodents and without considering the different follicular compartments.We used RNA-seq technology to explore the sheep transcriptome during early ovarian follicular development in the two main compartments: oocytes and granulosa cells. We documented the differential expression of 3,015 genes during this phase and described the gene expression dynamic specific to these compartments. We showed that important steps occurred during primary/secondary transition in sheep. We also described the in vivo molecular course of a number of pathways. In oocytes, these pathways documented the chronology of the acquisition of meiotic competence, migration and cellular organization, while in granulosa cells they concerned adhesion, the formation of cytoplasmic projections and steroid synthesis. This study proposes the involvement in this process of several members of the integrin and BMP families. The expression of genes such as Kruppel-like factor 9 (KLF9 and BMP binding endothelial regulator (BMPER was highlighted for the first time during early follicular development, and their proteins were also predicted to be involved in gene regulation. Finally, we selected a data set of 24 biomarkers that enabled the discrimination of early follicular stages and thus offer a molecular signature of early follicular growth. This set of biomarkers includes known genes such as SPO11 meiotic protein covalently bound to DSB (SPO11, bone morphogenetic protein 15 (BMP15 and WEE1 homolog 2 (S. pombe(WEE2 which play critical roles in follicular development but other biomarkers

  16. Study the Migration Process of Chemical Substances through the Packaging/Food Interface during Microwave Treatment

    Directory of Open Access Journals (Sweden)

    Fang Duan

    2013-01-01

    Full Text Available The diffusion of chemical substances from packaging into food endangers people’s health. The migration amount of the chemical substances increases with the time and temperature, but the diffusion process for different kinds of packaging materials differs much. Most recently, the research community showed a renewed interest on the diffusion process of chemical substances through packaging/food interface during microwave treatment. In this study, the diffusion coefficient model is suggested and then the migration process is studied based on Fick’s diffusion law. The results are finally compared with the experimental data, showing good agreement.

  17. Radiation chemical studies on the treatment of waste water

    International Nuclear Information System (INIS)

    The radiation induced reaction in aqueous solution was studied to develope the radiation treatment as a new technique for waste water and to elevate the effectiveness of radiation. The effectiveness of radiation was enhanced by combination of radiation induced reaction with conventional methods such as biological treatment and coagulation treatment. The synergistic effect of radiation and ozone was studied by using phenol and ethylene glycol. The chain reaction was observed in the radiation induced oxidation. The combination of radiation and ozone is considered to be one of the most useful method. In this report, the mechanism of each reaction and the applicability of the reaction to the treatment of waste water are discussed. (author)

  18. Chemical profile of crude oils in support of toxicity studies

    International Nuclear Information System (INIS)

    Acute and chronic exposure of fish to oil spills causes toxic effects at all life stages. Eighty per cent of the polycyclic aromatic hydrocarbons (PAHs) in oils are alkylated PAH compounds, requiring a specialized analysis for fingerprinting oil fractions. Fingerprinting provides important information for oil spill response to prevent exposure of fish to the most toxic oils. It helps determine the best control and remediation option. This study focused on characterizing the alkylphenanthrene class of PAH because it causes embryo-larval toxicity. The bioavailability of alkylphenanthrene was determined through a linear correlation between the capacity factor and LogP values in Mesa crude and ANS crude oils. The study makes it possible to predict the ecological risk of oil spills in aquatic ecosystems

  19. Physico-Chemical Studies of the Pvc K+ - Selective Membrane

    Directory of Open Access Journals (Sweden)

    Ana COROIAN

    2002-12-01

    Full Text Available A plasticized ion-selective membrane based on PVC matrix which tricrezylphosphate (TCP and containing K+ - ionophores (dibenzo-18-crown-6 and decyl-18-crown-6 was used to obtain a potentiometric potassium sensor. The potassium selective membranes were characterized in terms of their electrochemical and physical properties, surface morphology and structural parameters. The a.c. impedance, UV/VIS analysis of the membranes was also studied.

  20. Marine Sponges and Symbionts: Chemical and Biological Studies

    OpenAIRE

    Schmidt, Eric W.

    1999-01-01

    This thesis concerns two quite different types of research that are separated into distinct sections of the thesis, but which seek to answer the same question using diametrically opposite approaches. The first part (Chapters 1-8) covers research leading to novel, bioactive compounds in marine sponges, while the second (Chapters 9-10) involves molecular biological studies of symbiosis between microbes and sponges. Although these topics seem at first glance completely separate, they are in real...

  1. Study of physical, chemical and radiological characteristic of thermal water

    International Nuclear Information System (INIS)

    Hydrotherapy is an activity during which the practitioner is exposed to natural ionising radiation. Radon from deep geological layers constitutes the praincipal irradiation factor for the worker and the patient. The study of radiological impact requires specific measurements that should be compared with international commission of radiological protection (ICRP) recommendations. The objective of this study is to estimate the health risk for employees and patients in hydrotherapy spas in tunisia, by calculating the annual effective dose within the diffrent sites, to identify the sites that could present a hasard from radon and to establish a protection scheme for on workers in these spas. This study is performed inside of the tunisian thermal spas. It consists in separating 226 Ra and measuring its concentration in the thermal water of each spa and then, determining the radon concentration with solid state track detectors (SSTD) chosen for their sensitivity to alpha particles. The dose assessment results show that the estimates values were lower than the ICRP recommendations. In addition, the effective doses received by the workers are greater than those received by the patients due to the longer exposure time for the workers. (author). 79 refs 6)

  2. A Physico-Chemical Study of Some Areas of Fundamental Significance to Biophysics

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Devendra; McGlynn, S. P.

    1999-04-01

    This report covers: Radiation Signatures; Electronic Structure of Steroids, Vitamins, and others; Laser Optogalvanic Effect; Vacuum Ultraviolet Spectroscopy, including Electron Scattering, Photochemistry, and Magnetic Circular Dichroism; and Ozone.

  3. Geogenic signatures detectable in topsoils of urban and rural domains in the London region, UK, using parent material classified data

    OpenAIRE

    Appleton, J.D.; Johnson, C C; Ander, E.L.; Flight, D.M.A.

    2013-01-01

    Systematic mapping of the chemical environment of urban areas from around the world have shown varying degrees of control of element distributions by the underlying parent material (PM). The purpose of the study reported here is to assess whether geogenic signatures that dominate soil chemistry in rural domains of Eastern England and which are not strongly impacted by human activities, can also be detected in the London urban region. A PM soil chemistry mapping method is used to determine the...

  4. Study of the chemical freeze-out in nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    Heavy ion collisions at ultra-relativistic energies are studied in order to create and analyze the quark-gluon plasma, which subsequently hadronizes forming the hadrons. Hadron multiplicities and their correlations are observables which can provide information on the nature, composition and size of the medium from which they originate. The hadron yields measured in the energy range from SIS to RHIC are well described by the thermal model assuming chemical equilibrium among produced hadrons at freeze-out. To determine the parameters characterizing chemical freeze-out, we analyze particle yields in terms of temperature and baryon chemical potential. From the experimental data obtained with BRAHMS experiment, in Au-Au collisions, at 200 AGeV, we obtain the lowest value for the baryon chemical potential and a chemical freeze-out temperature of approximately 170 MeV. The net-baryon density of the central rapidity region has the lowest value, and could explain the baryon chemical potential behaviour. At the same energy, the baryon chemical potential increases from mid-rapidity to forward rapidities. This behaviour confirms that, the mid-rapidity region is almost a net-baryon free region, while in the forward rapidities region it still keeps a significant baryon content of the original colliding nuclei. The energy dependence of chemical parameters is also discussed. As the beam energy is increased, the value of chemical freeze-out temperature is higher while that of baryon chemical potential is lower. The trend of chemical potential shows less baryon stopping with increasing energy. (author)

  5. Chemical and spectroscopic studies of Cercidium praecox gum exudate.

    Science.gov (United States)

    León de Pinto, G; Martínez, M; Rivas, C

    1994-07-01

    The structure of the polysaccharide from Cercidium praecox (R&P) Harms gum exudate has been studied by Smith degradation, by sugar and methylation analyses, and by 13C NMR spectroscopy. The results showed a (1-->4)-xylan core. Some xylose residues are substituted at O-2 by alpha-D-glucuronic acid and 4-O-methyl-alpha-D-glucuronic acid residues. beta-D-Glucuronic acid is present, probably as terminal residues. The arabinose is present as alpha-L-furanose and beta-L-pyranose. PMID:8062287

  6. Study of the aqueous chemical treatment of uranium zirconium fuels

    International Nuclear Information System (INIS)

    A dry process has been studied for separating the uranium from the zirconium-either for recovering the enriched uranium from fuel element production waste, or with a view to treating this waste after irradiation. In this process the alloy is treated with hydrochloric acid at 400 deg. C in a fluidized corundum bed which causes the zirconium to volatilize as tetrachloride and the uranium to form the trichloride. This latter is then converted to the hexafluoride by attack with fluorure. After the laboratory tests, a first pilot plant with a capacity of 1 kg of alloy was tried out at the Fontenay-aux-Roses Nuclear Research Centre; this made it possible to fix the operational conditions for the process. An industrial scale plant was then built with the collaboration of the from Kuhlmann, and operated until a satisfactory process had been developed for treating the waste. This installation treats 3 kg/h of alloy with a yield for the hydrochloric acid of about 50 per cent and with a uranium loss in the zirconium tetrachloride of about 0.1 per cent. An active pilot plant capable of treating of treating a few kilos of irradiated alloy is now being studied. (authors)

  7. Comparison of metagenomic samples using sequence signatures

    Directory of Open Access Journals (Sweden)

    Jiang Bai

    2012-12-01

    Full Text Available Abstract Background Sequence signatures, as defined by the frequencies of k-tuples (or k-mers, k-grams, have been used extensively to compare genomic sequences of individual organisms, to identify cis-regulatory modules, and to study the evolution of regulatory sequences. Recently many next-generation sequencing (NGS read data sets of metagenomic samples from a variety of different environments have been generated. The assembly of these reads can be difficult and analysis methods based on mapping reads to genes or pathways are also restricted by the availability and completeness of existing databases. Sequence-signature-based methods, however, do not need the complete genomes or existing databases and thus, can potentially be very useful for the comparison of metagenomic samples using NGS read data. Still, the applications of sequence signature methods for the comparison of metagenomic samples have not been well studied. Results We studied several dissimilarity measures, including d2, d2* and d2S recently developed from our group, a measure (hereinafter noted as Hao used in CVTree developed from Hao’s group (Qi et al., 2004, measures based on relative di-, tri-, and tetra-nucleotide frequencies as in Willner et al. (2009, as well as standard lp measures between the frequency vectors, for the comparison of metagenomic samples using sequence signatures. We compared their performance using a series of extensive simulations and three real next-generation sequencing (NGS metagenomic datasets: 39 fecal samples from 33 mammalian host species, 56 marine samples across the world, and 13 fecal samples from human individuals. Results showed that the dissimilarity measure d2S can achieve superior performance when comparing metagenomic samples by clustering them into different groups as well as recovering environmental gradients affecting microbial samples. New insights into the environmental factors affecting microbial compositions in metagenomic samples

  8. A chemical study of individual green glasses and brown glasses from 15426 - Implications for their petrogenesis

    Science.gov (United States)

    Ma, M.-S.; Liu, Y.-G.; Schmitt, R. A.

    1982-01-01

    Systematic chemical analyses of individual Apollo 15 green glasses were performed in order to: (1) study chemical variations among them; (2) understand their petrogenesis and source region; and (3) study their possible relationships with mare basalts in general. Brown glasses were also analyzed in order to study their chemical variations and their petrogenetic relationships to green glasses and mare basalts. The chemical composition of green and brown glasses is shown and variation diagrams of Sc, Cr2O3, FeO, and Co abundances in green glasses are presented. Igneous fractionation, two component magma mixing, and partial melting of heterogeneous source materials are alternate scenarios to explain strong observed correlations. The composition of green glasses indicates that they were derived by partial melting of the fractionated cumulate source materials formed from a magma ocean which had experienced certain degrees of olivine and plagioclase fractional crystallization.

  9. UTSig: A Persian Offline Signature Dataset

    OpenAIRE

    Soleimani, Amir; Fouladi, Kazim; Araabi, Babak N.

    2016-01-01

    The crucial role of datasets in signature verification systems has motivated researchers to collect signature samples. However, with regard to the distinct characteristics of Persian signature, existing offline signature datasets cannot be used in Persian systems. This paper presents a new and public Persian offline signature dataset, UTSig, which consists of 8280 images from 115 classes that each class has 27 genuine, 3 opposite-hand signatures of the genuine signer, and 42 skilled forgeries...

  10. On the signature of LINCOS

    Science.gov (United States)

    Ollongren, Alexander

    2010-12-01

    Suppose the international SETI effort yields the discovery of some signal of evidently non-natural origin. Could it contain linguistic information formulated in some kind of Lingua Cosmica? One way to get insight into this matter is to consider what specific (bio) linguistic signature( s) could be attached to a cosmic language for interstellar communication—designed by humans or an alien society having reached a level of intelligence (and technology) comparable to or surpassing ours. For this purpose, we consider in the present paper the logico-linguistic system LINCOS for ( A)CETI, developed during a number of years by the author in several papers and a monograph [1]. The system has a two-fold signature, which distinguishes it significantly from natural languages. In fact abstract and concrete signatures can be distinguished. That an abstract kind occurs is due to the manner in which abstractions of reality are represented in LINCOS-texts. They can take compound forms because the system is multi-expressive—partly due to the availability of inductive (recursive) entities. On the other hand, the concrete signature of LINCOS is related to the distribution of delimiters and predefined tokens in texts. Assigning measures to concrete signatures will be discussed elsewhere. The present contribution concentrates on the abstract signature of the language. At the same time, it is realized that an alien Lingua Cosmica might, but not necessarily needs to have this kind of signatures.

  11. Physico-chemical studies for strontium sulfate radiation dosimeter

    Directory of Open Access Journals (Sweden)

    M.A.H. Rushdi

    2015-04-01

    Full Text Available Anhydrous strontium sulfate (SrSO4 has shown a promise candidate as a dosimeter for low dose applications producing unique EPR signals with γ-rays which it has a linear response relationship (r2 = 0.999 in the range of 1–100 Gy. The present study extended to evaluate the properties of strontium sulfate dosimeter in intermediate dose range of technology applications. It was observed that the intensity of the EPR signal at g = 2.01081 increases with a 3rd polynomial function in the range of 0.10–15 kGy. In addition, the radical (SO4− provides a stable signal with a good reproducibility (0.107%. Other physics characteristic including the collision of mass stopping power dependence of the system and the effect of atomic number in different energy regions were investigated. The uncertainty budget for high doses has obtained from the measurement with value of 3.57% at 2σ confidence level.

  12. Chemical Biology Studies on Molecular Diversity of Annonaceous Acetogenins

    Institute of Scientific and Technical Information of China (English)

    Yao Zhu-Jun

    2004-01-01

    Annonaceous acetogenins, isolated from the Annonaceae plants, have been attracting worldwide attention in recent years due to their biological activities, especially as growth inhibitors of certain tumor ceils [ 1 ]. They have been shown to function by blocking complex I in mitochondria [2] as well as ubiquinone-linked NADPH oxidase in the cells of specific tumor cell lines, including some multidrug-resistant ones [3]. These features make these acetogenins excellent leads for the new antitumor agents. In our previous work, the compounds 1a to 1d (Figure 1), which relies on structure simplification while maintaining all essential functionalities of the acetogenins, was in vitro tested against several human solid tumor cell lines and showed interesting cell selectivity [4]. All four analogues show remarkable activity against the HCT-8 and HT-29 cell lines, while compound 1c was found the best [4bi. In order to further investigate the effects of key structural features, a convergent parallel fragments assembly strategy was developed [4e]. In addition, the biological relevancies of typical annonaceous acetogenin mimetics were also studied [4f].

  13. Chemical study on the labeling of EDTB with 153Sm

    International Nuclear Information System (INIS)

    Objective: According to conjugation characteristic of N, N, N', N'-tetrakis (2-benzymidazolylmethyl)-1, 2-ethanediamine (EDTB) with lipiodol selectively retained within hepatic tumors, in this paper, the labeling of EDTB with therapeutic nuclide 153Sm was first systematically studied by different labeling pathways, to further develop new labeled compounds with 153Sm for the treatment of hepatocellular carcinoma. Methods: A radio-paper chromatography (RPC) was used to determine the purity of the labeled compound with the mixture of pyridine: ethanol: water (1:2:4, V/V) as developer. Using independence variable method, the effect of labeling conditions, such as reaction time, temperature and concentration of EDTB on labeling yield were investigated, and the in vitro stability of 153Sm-EDTB was also demonstrated by RPC. Results: the RPC analysis indicated that Rf value of free 153Sm or 153Sm-EDTB was 0.0-0.1 and 0.6-0.7, respectively. Using acetic acid as reaction medium, in an open nitrogen-pouring labeling system, heated in boiling water bath for not less than 30 min, the labeling yield of 153Sm-EDTB was more than 97% and could remain in 24 hours after preparing the labeled compound at room temperature. Conclusion: The optimum labeling method and conditions were achieved. The in vitro stability of 153Sm-EDTB was good; thereby this provided possibility for further preparation and biological research of potential therapeutic radiopharmaceutical labeled lipiodol with 153Sm via EDTB for liver cancer

  14. Paradigm Signature S8

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    不说不知道,Paradigm在北美市场可是占用率位居前列的品牌,而且产品在世界各地获奖连连.足以证明他的成功。但风光的背后,肯定离不开默默的耕耘。Paradigm工厂就在加拿大,全世界销售的Paradigm产品都出自这个地广人稀、资源丰富、风景优美的北美绿洲。Paradigm的产品线甚广,SignatureS8是其中的现役旗舰。和很多旗舰产品动不动就要价数十万的品牌相比,这个Paradigm的产品定位可是务实得多,

  15. Statistical clumped isotope signatures.

    Science.gov (United States)

    Röckmann, T; Popa, M E; Krol, M C; Hofmann, M E G

    2016-01-01

    High precision measurements of molecules containing more than one heavy isotope may provide novel constraints on element cycles in nature. These so-called clumped isotope signatures are reported relative to the random (stochastic) distribution of heavy isotopes over all available isotopocules of a molecule, which is the conventional reference. When multiple indistinguishable atoms of the same element are present in a molecule, this reference is calculated from the bulk (≈average) isotopic composition of the involved atoms. We show here that this referencing convention leads to apparent negative clumped isotope anomalies (anti-clumping) when the indistinguishable atoms originate from isotopically different populations. Such statistical clumped isotope anomalies must occur in any system where two or more indistinguishable atoms of the same element, but with different isotopic composition, combine in a molecule. The size of the anti-clumping signal is closely related to the difference of the initial isotope ratios of the indistinguishable atoms that have combined. Therefore, a measured statistical clumped isotope anomaly, relative to an expected (e.g. thermodynamical) clumped isotope composition, may allow assessment of the heterogeneity of the isotopic pools of atoms that are the substrate for formation of molecules. PMID:27535168

  16. Detection of signature volatiles for cariogenic microorganisms.

    Science.gov (United States)

    Hertel, M; Preissner, R; Gillissen, B; Schmidt-Westhausen, A M; Paris, S; Preissner, S

    2016-02-01

    The development of a breath test by the identification of volatile organic compounds (VOCs) emitted by cariogenic bacteria is a promising approach for caries risk assessment and early caries detection. The aim of the present study was to investigate the volatile profiles of three major cariogenic bacteria and to assess whether the obtained signatures were species-specific. Therefore, the headspaces above cultures of Streptococcus mutans, Lactobacillus salivarius and Propionibacterium acidifaciens were analysed after 24 and 48 h of cultivation using gas chromatography and mass spectrometry. A volatile database was queried for the obtained VOC profiles. Sixty-four compounds were detected within the analysed culture headspaces and were absent (36) or at least only present in minor amounts (28) in the control headspace. For S. mutans 18, for L. salivarius three and for P. acidifaciens five compounds were found to be unique signature VOCs. Database matching revealed that the identified signatures of all bacteria were unique. Furthermore, 13 of the 64 detected substances have not been previously reported to be emitted by bacteria or fungi. Specific VOC signatures were found in all the investigated bacteria cultures. The obtained results encourage further research to investigate the transferability to in vivo conditions towards the development of a breath test. PMID:26610336

  17. Nanoscale intracellular mass-density alteration as a signature of the effect of alcohol on early carcinogenesis: A transmission electron microscopy (TEM) study

    CERN Document Server

    Ghimire, Hemendra M; Sahay, Peeyush; Almabadi, Huda; Tripathi, Vibha; Skalli, Omar; Rao, R K; Pradhan, Prabhakar

    2015-01-01

    Alcohol consumption interferes with the functioning of multiple organ systems, causing changes in the chemistry, physiology and pathology of tissues and cellular organelles. Although epigenetic modifications underlie the development of cancer, exposure to carcinogenic chemicals, such as alcohol, can also contribute to disease development. However, the effects of chronic alcoholism on normal or pre-carcinogenic cells/tissues in different organelles are not well understood. Therefore, we herein study the effect of alcohol consumption on colonic nucleus using control and azoxymethane (AOM) and dextran sulfate sodium (DSS) treated carcinogenic mice. Previous studies showed that progression of carcinogenesis is associated with increase in the degree of intranuclear nanoscale structural disorder. In the present work, we quantify the degree of nanostructural disorder as a measure of carcinogenesis. To accomplish this, transmission electron microscopy (TEM) imaging of respective colonic epithelial cell nuclei are use...

  18. Secure mediated certificateless signature scheme

    Institute of Scientific and Technical Information of China (English)

    YANG Chen; MA Wen-ping; WANG Xin-mei

    2007-01-01

    Ju et al proposed a certificateless signature scheme with instantaneous revocation by introducing security mediator (SEM) mechanism. This article presents a detailed cryptoanalysis of this scheme and shows that, in their proposed scheme, once a valid signature has been produced, the signer can recover his private key information and the instantaneous revocation property will be damaged. Furthermore, an improved mediated signature scheme, which can eliminate these disadvantages, is proposed, and security proof of the improved scheme under elliptic curve factorization problem (ECFP) assumption and bilinear computational diffie-hellman problem (BCDH) assumption is also proposed.

  19. Glaciological and chemical studies on ice cores from Hans Tausen ice cap, Greenland

    DEFF Research Database (Denmark)

    Clausen, H.B.; Stampe, Mia; Hammer, C.U.;

    2001-01-01

    The paper presents studies of various chemical and isotopical parameters from ice cores drilled in the northernmost located ice cap, Hans Tausen Iskappe, Pearyland, Greenland (HT). The 346 m main core (MC95) was drilled to bedrock in 1995 as well as a 35 m shallow core (SC95). A 60 m shallow core...... selected for an analysis of dust and water soluble chemical components, including F-, CH3SO2-, Cl-, NO3-, SO42-, Na+, NH4+, K+, Mg2+ and Ca2+. Coulter counter technique was used for the dust measurements and the chemical analysis were carried out by ion chromatography....

  20. Long-term aging of elastomers: Chemical stress relaxation of fluorosilicone rubber and other studies

    Science.gov (United States)

    Kalfayan, S. H.; Mazzeo, A. A.; Silver, R. H.

    1971-01-01

    Aerospace applications of elastomers are considered, including: propellant binders, bladder materials for liquid propellant expulsion systems, and fuel tank sealants for high-speed aircraft. A comprehensive molecular theory for mechanical properties of these materials has been developed but has only been tested experimentally in cases where chemical degradation processes are excluded. Hence, a study is being conducted to ascertain the nature, extent, and rate of chemical changes that take place in some elastomers of interest. Chemical changes that may take place in the fluorosilicone elastomer, LS 420, which is regarded as a fuel and high-temperature-resistant rubber are investigated. The kinetic analysis of the chemical stress relaxation and gel permeation chromatography studies comprise the major portion of the report.

  1. Moessbauer study of the chemical state of gold in gold ores

    International Nuclear Information System (INIS)

    Information on the chemical state of gold in gold ores has been obtained by 197Au Moessbauer spectroscopy in cases where the state of this element cannot be determined by such standard methods as optical or electron microscopy. Ore concentrates consisting mainly of pyrite or arsenopyrite and roasted ore and matte samples were studied. The results yielded directly the respective amounts of metallic and chemically bound gold. Unless the gold is metallic, its chemical state in the ores turns out to be different from that in the minerals studied so far as reference materials. The chemical processes taking place during various treatments of the ores, such as roasting or leaching, can also be followed by Moessbauer spectroscopy. It is hoped that Moessbauer spectroscopy will eventually facilitate the development of more efficient methods of gold extraction

  2. Chemical ecology of the carrot fly, Psila rosae (F.): laboratory and field studies

    OpenAIRE

    Selby, Martin James

    2004-01-01

    The carrot fly (Psila rosae F.) is an important pest of the cultivated carrot (Daucus carota) and other crop species in the family Apiaceae, since the larvae burrow into and feed on the developing roots. Current P. rosae control relies heavily upon the use of chemical insecticides, but these are inadequate. The aims of this study were to investigate the chemical ecology of P. rosae, particularly with regard to long range attractant and repellent semiochemicals suitable for incorporation into ...

  3. Self-consistent Study on Color Transport in the Quark Gluon Plasma at Finite Chemical Potential

    CERN Document Server

    Defu, H; Jiarong, L; Defu, Hou; Ochs, Stefan; Jiarong, Li

    1996-01-01

    We calculate the relaxation time self-consistently to study the damping of collective color modes and the color conductivity in a QGP by deriving self-consistent equations for the damping rates of gluons and quarks to leading order QCD by TFD including a chemical potential for quarks. We show that the damping rates are not sensitive to the chemical potential whereas color conductivity is enhanced considerably.

  4. Application of Chemical Grouting as an Option of Removing Soil Moisture - a Case Study in the Reconstruction of the Church

    OpenAIRE

    Katunská Jana; Katunský Dušan

    2015-01-01

    The article provides an analysis of removing moisture from the soil masonry walls. The chemical pressure insulation may be considered as one of the alternatives. This paper describes the chemical waterproofing and points to a case study, which is a small church in the town of Košice. Renovation of the church took place in two stages, made using pressure chemical insulation for chemical grouting of envelope masonry. The appropriateness and effectiveness of the applied chemical methods can be s...

  5. Observational signatures of binary supermassive black holes

    Energy Technology Data Exchange (ETDEWEB)

    Roedig, Constanze; Krolik, Julian H. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Miller, M. Coleman [Department of Astronomy and Joint Space-Science Institute, University of Maryland, College Park, MD 20742 (United States)

    2014-04-20

    Observations indicate that most massive galaxies contain a supermassive black hole, and theoretical studies suggest that when such galaxies have a major merger, the central black holes will form a binary and eventually coalesce. Here we discuss two spectral signatures of such binaries that may help distinguish them from ordinary active galactic nuclei. These signatures are expected when the mass ratio between the holes is not extreme and the system is fed by a circumbinary disk. One such signature is a notch in the thermal continuum that has been predicted by other authors; we point out that it should be accompanied by a spectral revival at shorter wavelengths and also discuss its dependence on binary properties such as mass, mass ratio, and separation. In particular, we note that the wavelength λ {sub n} at which the notch occurs depends on these three parameters in such a way as to make the number of systems displaying these notches ∝λ{sub n}{sup 16/3}; longer wavelength searches are therefore strongly favored. A second signature, first discussed here, is hard X-ray emission with a Wien-like spectrum at a characteristic temperature ∼100 keV produced by Compton cooling of the shock generated when streams from the circumbinary disk hit the accretion disks around the individual black holes. We investigate the observability of both signatures. The hard X-ray signal may be particularly valuable as it can provide an indicator of black hole merger a few decades in advance of the event.

  6. Chemical and radiation environmental risk management at the crossroads: Case studies

    International Nuclear Information System (INIS)

    Although many of the major environmental risk management decisions we face today require the simultaneous evaluation and control of both radiological and chemical risks, the separation of radiation and chemical risk management persists along legal, regulatory, programmatic, training and professional practice levels. In June 1998, a panel of 40 chemical and radiation risk experts met at an interactive workshop entitled 'Addressing the Similarities and Differences in Chemical and Radiation Environmental Risk Management,' in Annapolis, Maryland to discuss several perspectives on harmonizing chemical and radiation risk management approaches. At the conclusion of the meeting, workshop participants recommended that case studies of clean-up sites at which radioactive materials and hazardous chemical risks were addressed, be developed to help educate participants in the harmonization dialogue about their counterpart's issues, stimulate discussion and sharpen issues in a way that they can be resolved. Several key risk management issues that were highlighted from the discussion at the Annapolis meeting are being evaluated in the case studies. They include: decision criteria, costs and public/stakeholder input. This paper presents these key issues and the approach taken in the case studies. (author)

  7. Chemical and geochemical studies off the coast of Washington. Progress report, September 1980-July 1981

    International Nuclear Information System (INIS)

    This report summarizes progress from September 1980 through July 1981 on a series of marine chemical and geochemical investigations involving both laboratory studies and field studies off the coast of Washington. Most of the field work has been on the Washington continental shelf, slope, and the submarine canyons indenting the shelf north of the Columbia River. The aim is to provide basic data required to characterize underlying chemical and physical processes and their rates which control the distributions, concentrations, and ultimate fate of some of the potentially hazardous agents associated with fossil fuel and/or nuclear power production or transportation. We are concentrating on several processes which we feel are of special importance in the sea, and developing methodologies and expertise to study them. Laboratory and field experiments and theories derived from them are being used iteratively to investigate: (1) vertical transfer of trace chemicals from surface seawaters to underlying waters and sediments; (2) processes which may transfer certain chemicals from sediments back into the overlying water column; (3) redox processes which besides changing valence states of certain chemicals may alter their precipitation/dissolution tendencies, their biological availability and/or toxicity; and (4) accumulation histories of potentially hazardous chemicals in sediments during the past 100 years

  8. Progress report on SYVAC chemical speciation modelling studies during 1983/4

    International Nuclear Information System (INIS)

    This report summarises progress made on the SYVAC (System Variability Analysis program) chemical speciation project during 1983-4. Chemical speciation is defined and its importance in the SYVAC approach to Radioactive Waste Management is discussed. Computer modelling of chemical equilibria is described and the two programs presently operational at UWIST - SOLMNQ and MINEQL - are compared and discussed in detail. In view of the shortcomings of the databases supplied with these programs, a new database of equilibrium constants has been compiled containing 483 aqueous species and 329 solid phases, including data for the radionuclides uranium, plutonium, americium, neptunium and thorium. The collaborative work with AERE, Harwell, is reported. A leaching experiment carried out at Harwell has been modelled using the chemical speciation programs. The results for uranium, plutonium, americium and neptunium, are presented. However, the experimental data provided by AERE is insufficient for accurate simulations. Chemical speciation studies relating to specific sites require accurate characterisation of the groundwater, i.e. chemical composition, Eh and pH. In the absence of such information, preliminary studies have been made using an average granite groundwater. The results of these studies are presented and include solubility and speciation plots for uranium, plutonium, thorium and neptunium. The future aims of the project are discussed. (author)

  9. Initial Semantics for Strengthened Signatures

    CERN Document Server

    Hirschowitz, André; 10.4204/EPTCS.77.5

    2012-01-01

    We give a new general definition of arity, yielding the companion notions of signature and associated syntax. This setting is modular in the sense requested by Ghani and Uustalu: merging two extensions of syntax corresponds to building an amalgamated sum. These signatures are too general in the sense that we are not able to prove the existence of an associated syntax in this general context. So we have to select arities and signatures for which there exists the desired initial monad. For this, we follow a track opened by Matthes and Uustalu: we introduce a notion of strengthened arity and prove that the corresponding signatures have initial semantics (i.e. associated syntax). Our strengthened arities admit colimits, which allows the treatment of the \\lambda-calculus with explicit substitution.

  10. Initial Semantics for Strengthened Signatures

    Directory of Open Access Journals (Sweden)

    André Hirschowitz

    2012-02-01

    Full Text Available We give a new general definition of arity, yielding the companion notions of signature and associated syntax. This setting is modular in the sense requested by Ghani and Uustalu: merging two extensions of syntax corresponds to building an amalgamated sum. These signatures are too general in the sense that we are not able to prove the existence of an associated syntax in this general context. So we have to select arities and signatures for which there exists the desired initial monad. For this, we follow a track opened by Matthes and Uustalu: we introduce a notion of strengthened arity and prove that the corresponding signatures have initial semantics (i.e. associated syntax. Our strengthened arities admit colimits, which allows the treatment of the λ-calculus with explicit substitution.

  11. Equiangular Frames and Signature Sets

    OpenAIRE

    Singh, Preeti

    2009-01-01

    We will present a relation between real equiangular frames and certain special sets in groups which we call signature sets and show that many equiangular frames arise in this manner. Then we will define quasi-signature sets and will examine equiangular frames associated to these subsets of groups. We will extend these results to complex equiangular frames where the inner product between any pair of vectors is a common multiple of a cube root of unity and exhibit equiangular frames that arise ...

  12. Object Recognition Using Spatiotemporal Signatures

    OpenAIRE

    James V Stone

    1998-01-01

    The sequence of images generated by motion between observer and object specifies a spatiotemporal signature for that object. Evidence is presented that such spatiotemporal signatures are used in object recognition. Subjects learned novel, three-dimensional, rotating objects from image sequences in a continuous recognition task. During learning, the temporal order of images of a given object was constant. During testing, the order of images in each sequence was reversed, relative to its order ...

  13. An arbitrated quantum signature scheme

    CERN Document Server

    Zeng, G; Zeng, Guihua; Keitel, Christoph H.

    2002-01-01

    The general principle for a quantum signature scheme is proposed and investigated based on ideas from classical signature schemes and quantum cryptography. The suggested algorithm is implemented by a symmetrical quantum key cryptosystem and Greenberger-Horne-Zeilinger (GHZ) triplet states and relies on the availability of an arbitrator. We can guarantee the unconditional security of the algorithm, mostly due to the correlation of the GHZ triplet states and the use of quantum one-time pads.

  14. Contract Signature Using Quantum Information

    CERN Document Server

    De Sousa, P B M; Ramos, Rubens Viana; Sousa, Paulo Benicio Melo de

    2006-01-01

    This paper describes how to perform contract signature in a fair way using quantum information. The protocol proposed permits two partners, users of a communication network, to exchange their signatures with non-repudiation. For this, we assume that there is a trustable arbitrator, responsible for the authentication of the signers and that performs a central task in a quantum teleportation protocol of the XOR function between two classical bits.

  15. Visual identification by signature tracking

    OpenAIRE

    Munich, Mario E.; Perona, Pietro

    2003-01-01

    We propose a new camera-based biometric: visual signature identification. We discuss the importance of the parameterization of the signatures in order to achieve good classification results, independently of variations in the position of the camera with respect to the writing surface. We show that affine arc-length parameterization performs better than conventional time and Euclidean arc-length ones. We find that the system verification performance is better than 4 percent error on skilled fo...

  16. Resolving Optimum Magnetic Signatures for Drill-Hole Targeting in Gold Exploration – A Case Study for Mbudzane in Gwanda, Zimbabwe

    OpenAIRE

    Dumisani John Hlatywayo; Emmanuel Sakala

    2014-01-01

    Optimum magnetic signatures for drill-hole targeting in gold exploration in Mbudzane were resolved from induced polarisation-resistivity and magnetic anomalies. Total magnetic field and a gold-in-soil map showed the area is magnetically quiet with high anomalous values along old gold workings. Induced polarisation was carried out along a grid for lines of 500m length, 50m separation and a baseline oriented at 330˚. The survey comprised a gradient array and three real sections. The magnetic su...

  17. Accuracy of self-reported intake of signature foods in a school meal intervention study: comparison between control and intervention period

    DEFF Research Database (Denmark)

    Biltoft-Jensen, Anja Pia; Damsgaard, Camilla Trab; Andersen, Rikke;

    2015-01-01

    the NND. Children, assisted by parents, self-reported their diet in a Web-based Dietary Assessment Software for Children during the intervention and control (packed lunch) periods. The reported fish intake by children was compared with their ranking according to fasting whole-blood EPA and DHA...... compared with the reporting of signature foods in both periods, and the accuracy was higher during the control period compared with the intervention period. Both Spearman's rank correlations and linear mixed models demonstrated positive associations between EPA+DHA and reported fish intake. The direct...

  18. Nuclear, chemical, and physical characterization of nuclear materials

    International Nuclear Information System (INIS)

    The goal of nuclear forensics is to establish an unambiguous link between illicitly trafficked nuclear material and its origin. The Los Alamos National Laboratory (LANL) Nuclear Materials Signatures Program has implemented a graded 'conduct of operations' type analysis flow path approach for determining the key nuclear, chemical, and physical signatures needed to identify the manufacturing process, intended use, and origin of interdicted nuclear material. This analysis flow path includes both destructive and non-destructive characterization techniques and has been exercized against different nuclear materials from LANL's special nuclear materials archive. Results obtained from the case study will be presented to highlight analytical techniques that offer the critical attribution information. (author)

  19. Medium scale test study of chemical cleaning technique for secondary side of SG in PWR

    International Nuclear Information System (INIS)

    The medium scale test study of chemical cleaning technique for removing corrosion product (Fe3O4) in secondary side of SG in PWR has been completed. The test has been carried out in a medium scale test loop. The medium scale test evaluated the effect of the chemical cleaning technique (temperature, flow rate, cleaning time, cleaning process), the state of corrosion product deposition on magnetite (Fe3O4) solubility and safety of materials of SG in cleaning process. The inhibitor component of chemical cleaning agent has been improved by electrochemical linear polarization method, the effect of inhibitor on corrosion resistance of materials have been examined in the medium scale test loop, the most components of chemical cleaning agent have been obtained, the EDTA is main component in cleaning agent. The electrochemical method for monitor corrosion of materials during cleaning process has been completed in the laboratory. The study of the medium scale test of chemical cleaning technique have had the optimum chemical cleaning technique for remove corrosion product in SG secondary side of PWR. (9 refs., 4 figs., 11 tabs.)

  20. Noise sensitivity and multiple chemical sensitivity scales: Properties in a population based epidemiological study

    Directory of Open Access Journals (Sweden)

    Marja Heinonen-Guzejev

    2012-01-01

    Full Text Available Noise sensitivity is considered to be a self-perceived indicator of vulnerability to stressors in general and not noise alone. Multiple chemical sensitivity (MCS has to some extent been accompanied by noise sensitivity, indicating a moderate correspondence between them. The aim of this study is to investigate if the Weinstein′s Noise Sensitivity Scale and Quick Environmental Exposure and Sensitivity Inventory′s (QEESI Chemical Intolerance Subscale can differentiate noise sensitivity and MCS as different entities, and if there are overlaps in the characteristics of noise sensitivity and MCS. In 2002, 327 individuals (166 men, 161 women; age range 45 - 66 years from the Finnish Twin Cohort answered a questionnaire on noise-related and MCS items. Somatic, psychological, and lifestyle factors were obtained through earlier questionnaires for the same individuals. Both confirmatory and exploratory factor analyses (CFA and EFA of the questionnaire items on the Weinstein′s Noise Sensitivity Scale and QEESI′s Chemical Intolerance Subscale indicated the presence of three factors - Noise Sensitivity, Chemical Sensitivity, and Ability to Concentrate factors - arising from the forming of two factors from the items of the Weinstein′s scale. In the regression analyses, among all subjects, the Noise Sensitivity Factor was associated with neuroticism and smoking, and the Chemical Sensitivity Factor was associated with allergies and alcohol use. The study indicates that the Weinstein′s Noise Sensitivity Scale and QEESI′s Chemical Intolerance Subscale differentiate noise sensitivity and MCS as different entities.

  1. SIGNATURE: A workbench for gene expression signature analysis

    Directory of Open Access Journals (Sweden)

    Chang Jeffrey T

    2011-11-01

    Full Text Available Abstract Background The biological phenotype of a cell, such as a characteristic visual image or behavior, reflects activities derived from the expression of collections of genes. As such, an ability to measure the expression of these genes provides an opportunity to develop more precise and varied sets of phenotypes. However, to use this approach requires computational methods that are difficult to implement and apply, and thus there is a critical need for intelligent software tools that can reduce the technical burden of the analysis. Tools for gene expression analyses are unusually difficult to implement in a user-friendly way because their application requires a combination of biological data curation, statistical computational methods, and database expertise. Results We have developed SIGNATURE, a web-based resource that simplifies gene expression signature analysis by providing software, data, and protocols to perform the analysis successfully. This resource uses Bayesian methods for processing gene expression data coupled with a curated database of gene expression signatures, all carried out within a GenePattern web interface for easy use and access. Conclusions SIGNATURE is available for public use at http://genepattern.genome.duke.edu/signature/.

  2. Quantum messages with signatures forgeable in arbitrated quantum signature schemes

    Science.gov (United States)

    Kim, Taewan; Choi, Jeong Woon; Jho, Nam-Su; Lee, Soojoon

    2015-02-01

    Even though a method to perfectly sign quantum messages has not been known, the arbitrated quantum signature scheme has been considered as one of the good candidates. However, its forgery problem has been an obstacle to the scheme becoming a successful method. In this paper, we consider one situation, which is slightly different from the forgery problem, that we use to check whether at least one quantum message with signature can be forged in a given scheme, although all the messages cannot be forged. If there are only a finite number of forgeable quantum messages in the scheme, then the scheme can be secured against the forgery attack by not sending forgeable quantum messages, and so our situation does not directly imply that we check whether the scheme is secure against the attack. However, if users run a given scheme without any consideration of forgeable quantum messages, then a sender might transmit such forgeable messages to a receiver and in such a case an attacker can forge the messages if the attacker knows them. Thus it is important and necessary to look into forgeable quantum messages. We show here that there always exists such a forgeable quantum message-signature pair for every known scheme with quantum encryption and rotation, and numerically show that there are no forgeable quantum message-signature pairs that exist in an arbitrated quantum signature scheme.

  3. Orbiting circumgalactic gas as a signature of cosmological accretion

    OpenAIRE

    Stewart, K. R.; Kaufmann, T; Bullock, J S; Barton, E. J.; Maller, A. H.; Diemand, J.; Wadsley, J.

    2011-01-01

    We use cosmological smoothed particle hydrodynamic simulations to study the kinematic signatures of cool gas accretion onto a pair of well-resolved galaxy halos. We find that cold-flow streams and gas-rich mergers produce a circumgalactic component of cool gas that generally orbits with high angular momentum about the galaxy halo before falling in to build the disk. This signature of cosmological accretion should be observable using background-object absorption-line studies as features that a...

  4. 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.

  5. Quantum Gravity signatures in the Unruh effect

    OpenAIRE

    Alkofer, Natalia; D'Odorico, Giulio; Saueressig, Frank; Versteegen, Fleur

    2016-01-01

    We study quantum gravity signatures emerging from phenomenologically motivated multiscale models, spectral actions, and Causal Set Theory within the detector approach to the Unruh effect. We show that while the Unruh temperature is unaffected, Lorentz-invariant corrections to the two-point function leave a characteristic fingerprint in the induced emission rate of the accelerated detector. Generically, quantum gravity models exhibiting dynamical dimensional reduction exhibit a suppression of ...

  6. Signatures of homoclinic motion in quantum chaos

    OpenAIRE

    Wisniacki, D. A.; Vergini, E.; Benito, R. M.; Borondo, F.

    2004-01-01

    Homoclinic motion plays a key role in the organization of classical chaos in Hamiltonian systems. In this Letter, we show that it also imprints a clear signature in the corresponding quantum spectra. By numerically studying the fluctuations of the widths of wavefunctions localized along periodic orbits we reveal the existence of an oscillatory behavior, that is explained solely in terms of the primary homoclinic motion. Furthermore, our results indicate that it survives the semiclassical limit.

  7. An Efficient ECDSA-Based Signature Scheme for Wireless Networks

    Institute of Scientific and Technical Information of China (English)

    XU Zhong; DAI Guanzhong; YANG Deming

    2006-01-01

    Wired equivalent security is difficult to provide in wireless networks due to high dynamics, wireless link vulnerability, and decentralization. The Elliptic Curve Digital Signature Algorithm(ECDSA) has been applied to wireless networks because of its low computational cost and short key size, which reduces the overheads in a wireless environment. This study improves the ECDSA scheme by reducing its time complexity. The significant advantage of the algorithm is that our new scheme needs not to calculate modular inverse operation in the phases of signature generation and signature verification. Such an improvement makes the proposed scheme more efficient and secure.

  8. Dissecting genetic and environmental mutation signatures with model organisms.

    Science.gov (United States)

    Segovia, Romulo; Tam, Annie S; Stirling, Peter C

    2015-08-01

    Deep sequencing has impacted on cancer research by enabling routine sequencing of genomes and exomes to identify genetic changes associated with carcinogenesis. Researchers can now use the frequency, type, and context of all mutations in tumor genomes to extract mutation signatures that reflect the driving mutational processes. Identifying mutation signatures, however, may not immediately suggest a mechanism. Consequently, several recent studies have employed deep sequencing of model organisms exposed to discrete genetic or environmental perturbations. These studies exploit the simpler genomes and availability of powerful genetic tools in model organisms to analyze mutation signatures under controlled conditions, forging mechanistic links between mutational processes and signatures. We discuss the power of this approach and suggest that many such studies may be on the horizon. PMID:25940384

  9. IR study on surface chemical properties of catalytic grown carbon nanotubes and nanofibers

    Institute of Scientific and Technical Information of China (English)

    Li-hua TENG; Tian-di TANG

    2008-01-01

    In this study, the surface chemical properties of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) grown by catalytic decomposition of methane on nickel and cobalt based catalysts were studied by DRIFT (Diffuse Reflectance Infrared Fourier Transform) and transmission Infrared (IR) spectroscopy. The results show that the surface exists not only carbon-hydrogen groups, but also carboxyl, ketene or quinone (carbonyl) oxygen-containing groups. These functional groups were formed in the process of the material growth, which result in large amount of chemical defect sites on the walls.

  10. Chemical compatibility study of Cooley L18KU, Herculite, and Elephant Mat with Hanford tank waste

    International Nuclear Information System (INIS)

    An independent chemical compatibility review of various wrapping and absorbent/padding materials was conducted to evaluate resistance to chemicals and constituents present in liquid waste from the Hanford underground tanks. These materials will be used to wrap long-length contaminated equipment when such equipment is removed from the tanks and prepared for transportation and subsequent disposal or storage. The materials studied were Cooley L18KU, Herculite, and Elephant Mat. The study concludes that these materials are appropriate for use in this application

  11. Using Physiologically-Based Pharmacokinetic Models to Incorporate Chemical and Non-Chemical Stressors into Cumulative Risk Assessment: A Case Study of Pesticide Exposures

    Directory of Open Access Journals (Sweden)

    Jonathan I. Levy

    2012-05-01

    Full Text Available Cumulative risk assessment has been proposed as an approach to evaluate the health risks associated with simultaneous exposure to multiple chemical and non-chemical stressors. Physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD models can allow for the inclusion and evaluation of multiple stressors, including non-chemical stressors, but studies have not leveraged PBPK/PD models to jointly consider these disparate exposures in a cumulative risk context. In this study, we focused on exposures to organophosphate (OP pesticides for children in urban low-income environments, where these children would be simultaneously exposed to other pesticides (including pyrethroids and non-chemical stressors that may modify the effects of these exposures (including diet. We developed a methodological framework to evaluate chemical and non-chemical stressor impacts on OPs, utilizing an existing PBPK/PD model for chlorpyrifos. We evaluated population-specific stressors that would influence OP doses or acetylcholinesterase (AChE inhibition, the relevant PD outcome. We incorporated the impact of simultaneous exposure to pyrethroids and dietary factors on OP dose through the compartments of metabolism and PD outcome within the PBPK model, and simulated combinations of stressors across multiple exposure ranges and potential body weights. Our analyses demonstrated that both chemical and non-chemical stressors can influence the health implications of OP exposures, with up to 5-fold variability in AChE inhibition across combinations of stressor values for a given OP dose. We demonstrate an approach for modeling OP risks in the presence of other population-specific environmental stressors, providing insight about co-exposures and variability factors that most impact OP health risks and contribute to children’s cumulative health risk from pesticides. More generally, this framework can be used to inform cumulative risk assessment for any compound impacted by

  12. TREATABILITY STUDIES USED TO TEST FOR EXOTHERMIC REACTIONS OF PLUTONIUM DECONTAMINATION CHEMICALS

    International Nuclear Information System (INIS)

    Fluor Hanford is decommissioning the Plutonium Finishing Plant (PFP) at the Hanford site in Eastern Washington. Aggressive chemicals are commonly used to remove transuranic contaminants from process equipment to allow disposal as low level waste. Chemicals being considered for decontamination of gloveboxes in PFP include cerium(IV) nitrate in a nitric acid solution, and proprietary commercial solutions that include acids, degreasers, and sequestering agents. Fluor's decontamination procedure involves application of chemical solutions as a spray on the contaminated surfaces, followed by a wipe-down with rags. This process effectively transfers the transuranic materials to the decontamination liquids, which are then absorbed by rags and packaged for disposal as TRU waste. Concerns regarding the safety of this procedure developed following a fire at Rocky Flats in 2003. The fire occurred in a glovebox that had been treated with cerium nitrate, which is one of the decontamination chemicals that Fluor Hanford has proposed to use. The investigation of the event was hampered by the copious use of chemicals and water to extinguish the fire, and was not conclusive regarding the cause. However, the reviewers noted that rags were found in the glovebox, suggesting that the combination of rags and chemicals may have contributed to the fire. With that uncertainty, Fluor began an investigation into the potential for fire when using the chemicals and materials in the decontamination process. The focus of this work has been to develop a disposal strategy that will provide a chemically stable waste form at expected Hanford waste storage temperatures. Treatability tests under CERCLA were used to assess the use of certain chemicals and wipes during the decontamination process. Chemicals being considered for decontamination of gloveboxes at PFP include cerium (IV) nitrate in a nitric acid solution, and proprietary commercial solutions as RadPro(trademark) that include acids, degreasers

  13. A physico-chemical study of some areas of fundamental significance to biophysics

    International Nuclear Information System (INIS)

    This report discusses the following topics: Radiation signatures; photoelectron spectroscopy of biologically active molecules; laser optogalvanic effect; magnetic circular dichroism; photochemistry of halogenated molecules; and density effects on high-n rydbergs

  14. A physico-chemical study of some areas of fundamental significance to biophysics

    Energy Technology Data Exchange (ETDEWEB)

    McGlynn, S.P.; Kumar, D.

    1992-04-30

    This report discusses the following topics: Radiation signatures; photoelectron spectroscopy of biologically active molecules; laser optogalvanic effect; magnetic circular dichroism; photochemistry of halogenated molecules; and density effects on high-n rydbergs.

  15. The infrared signatures of very small grains in the Universe seen by JWST

    CERN Document Server

    Pilleri, Paolo; Joblin, Christine

    2015-01-01

    The near- and mid-IR spectrum of many astronomical objects is dominated by emission bands due to UV-excited polycyclic aromatic hydrocarbons (PAH) and evaporating very small grains (eVSG). Previous studies with the ISO, Spitzer and AKARI space telescopes have shown that the spectral variations of these features are directly related to the local physical conditions that induce a photo-chemical evolution of the band carriers. Because of the limited sensitivity and spatial resolution, these studies have focused mainly on galactic star-forming regions. We discuss how the advent of JWST will allow to extend these studies to previously unresolved sources such as near-by galaxies, and how the analysis of the infrared signatures of PAHs and eVSGs can be used to determine their physical conditions and chemical composition.

  16. International coordinated research on the chemical modification of cancer treatment using AK-2123- clinical study

    International Nuclear Information System (INIS)

    The international coordinated clinical study on the AK-2123 sensitized radiotherapy demonstrated the promising results to improve the radiation response of various tumors such as oral cavity, head and neck, lung, esophagus, mammary, uterine cervical, endometrium and others. On the basis of the extensive fundamental studies on the multimodality treatment of cancer using AK-2123 and other chemical modifiers, further clinical study will achieve more higher curability in the radiotherapy of various cancers. 23 refs., tabs

  17. Graph Analytics for Signature Discovery

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, Emilie A.; Johnson, John R.; Halappanavar, Mahantesh; Lo, Chaomei

    2013-06-01

    Within large amounts of seemingly unstructured data it can be diffcult to find signatures of events. In our work we transform unstructured data into a graph representation. By doing this we expose underlying structure in the data and can take advantage of existing graph analytics capabilities, as well as develop new capabilities. Currently we focus on applications in cybersecurity and communication domains. Within cybersecurity we aim to find signatures for perpetrators using the pass-the-hash attack, and in communications we look for emails or phone calls going up or down a chain of command. In both of these areas, and in many others, the signature we look for is a path with certain temporal properties. In this paper we discuss our methodology for finding these temporal paths within large graphs.

  18. 78 FR 68461 - Guidance for Industry: Studies To Evaluate the Utility of Anti-Salmonella Chemical Food Additives...

    Science.gov (United States)

    2013-11-14

    ... Anti- Salmonella Chemical Food Additives in Feeds; Request for Comments AGENCY: Food and Drug... Chemical Food Additives in Feeds,'' and is seeking comments on this guidance before revisions are made... Guidance for Industry: Studies to Evaluate the Utility of Anti-Salmonella Chemical Food Additives in...

  19. A detailed comparative study between chemical and bioactive properties of Ganoderma lucidum from different origins

    NARCIS (Netherlands)

    Stojkovic, D.S.; Barros, L.; Calhelha, R.C.; Glamoclija, J.; Ciric, A.; Griensven, van L.J.L.D.; Sokovic, M.; Ferreira, I.C.F.R.

    2014-01-01

    A detailed comparative study on chemical and bioactive properties of wild and cultivated Ganoderma lucidum from Serbia (GS) and China (GCN) was performed. This species was chosen because of its worldwide use as medicinal mushroom. Higher amounts of sugars were found in GS, while higher amounts of or

  20. Upper Secondary French Students, Chemical Transformations and the "Register of Models": A Cross-Sectional Study

    Science.gov (United States)

    Cokelez, Aytekin; Dumon, Alain; Taber, Keith S.

    2008-01-01

    The purpose of this study is to identify how upper secondary school French students (Grade 10-12) interpret chemical transformation with regards to the changes within molecules and atoms, and in terms of intramolecular and/or intermolecular bond breaking. In order to identify and describe the students' assimilated knowledge, four questions were…

  1. The Competence of Modelling in Learning Chemical Change: A Study with Secondary School Students

    Science.gov (United States)

    Oliva, José Mª; del Mar Aragón, María; Cuesta, Josefa

    2015-01-01

    The competence of modelling as part of learning about chemical change is analysed in a sample of 35 secondary students, ages 14-15 years, during their study of a curricular unit on this topic. The teaching approach followed is model based, with frequent use of analogies and mechanical models (fruits and bowls, Lego pieces, balls of plasticine,…

  2. STUDY REGARDING SOME PHYSICAL - CHEMICAL CHARACTERISTICS OF THE YOGHURT WITH RED BEETROOT JUICE

    OpenAIRE

    Natalia Prodaniuc

    2009-01-01

    The study presents some physical - chemical characteristics of the beetroot juice yoghurt. The following determinations were carried out: the determination of the acidity by titration with sodium hydroxide ( NaOH ) N/10, the determination of the fat content by the acid-butirometric method and the determination of the dry substance using the drying oven with a 102 °C temperature.

  3. The study of metal sulphide nanomaterials obtained by chemical bath deposition and hot-injection technique

    Science.gov (United States)

    Maraeva, E. V.; Alexandrova, O. A.; Forostyanaya, N. A.; Levitskiy, V. S.; Mazing, D. S.; Maskaeva, L. N.; Markov, V. Ph; Moshnikov, V. A.; Shupta, A. A.; Spivak, Yu M.; Tulenin, S. S.

    2015-11-01

    In this study lead sulphide - cadmium sulphide based layers were obtained through chemical deposition of water solutions and cadmium sulphide quantum dots were formed through hot-injection technique. The article discusses the results of surface investigations with the use of atomic force microscopy, Raman spectroscopy and photoluminescence measurements.

  4. Lifetimes of organic photovoltaics: Combining chemical and physical characterisation techniques to study degradation mechanisms

    DEFF Research Database (Denmark)

    Norrman, K.; Larsen, N.B.; Krebs, Frederik C

    2006-01-01

    Degradation mechanisms of a photovoltaic device with an Al/C-60/C-12-PSV/PEDOT:PSS/ITO/glass geometry was studied using a combination of in-plane physical and chemical analysis techniques: TOF-SIMS, AFM, SEM, interference microscopy and fluorescence microscopy. A comparison was made between a...

  5. CO[subscript 2] Rebreathing: An Undergraduate Laboratory to Study the Chemical Control of Breathing

    Science.gov (United States)

    Domnik, N. J.; Turcotte, S. E.; Yuen, N. Y.; Iscoe, S.; Fisher, J. T.

    2013-01-01

    The Read CO[subscript]2 rebreathing method (Read DJ. "A clinical method for assessing the ventilatory response to carbon dioxide." "Australas Ann Med" 16: 20-32, 1967) provides a simple and reproducible approach for studying the chemical control of breathing. It has been widely used since the modifications made by Duffin and…

  6. Green chemicals : A Kinetic Study on the Conversion of Glucose to Levulinic Acid

    NARCIS (Netherlands)

    Girisuta, B.; Janssen, L.P.B.M.; Heeres, H.J.

    2006-01-01

    Levulinic acid has been identified as a promising green, biomass derived platform chemical. A kinetic study on one of the key steps in the conversion of biomass to levulinic acid, i.e., the acid catalysed decomposition of glucose to levulinic acid has been performed. The experiments were performed i

  7. Global duality, signature calculus and the discrete logarithm problem

    OpenAIRE

    Huang, Ming-Deh; Raskind, Wayne

    2007-01-01

    We study the discrete logarithm problem for the multiplicative group and for elliptic curves over a finite field by using a lifting of the corresponding object to an algebraic number field and global duality. We introduce the \\textit{signature} of a Dirichlet character (in the multiplicative group case) or principal homogeneous space (in the elliptic curve case), which is a measure of the ramification at certain places. We then develop \\textit{signature calculus}, which generalizes and refine...

  8. PRELIMINARY STUDY ON ENHANCED PROPERTIES AND BIOLOGICAL RESISTANCE OF CHEMICALLY MODIFIED ACACIA SPP.

    Directory of Open Access Journals (Sweden)

    H. P. S. Abdul Khalil

    2010-11-01

    Full Text Available A preliminary experimental study was carried out to examine the ability of a chemically modified Acacia spp. to resist biodegradation. The modifications of Acacia mangium and Acacia hybrid were carried out by propionic anhydride and succinic anhydride in the presence of sodium formate as a catalyst. The treated samples were found resistant to microbial attack, while the untreated ones were damaged on 12 months exposure to a soil burial. The appearance grading, mass loss, mechanical properties, and scanning electron microscopy results revealed that chemical modification enhances the resistance of Acacia mangium and Acacia hybrid wood species to biodegradation.

  9. Study on the chemical species of platinum group elements in geological samples by molecular activation analysis

    International Nuclear Information System (INIS)

    The chemical species of platinum group elements in some upper mantle-derived xenoliths from Eastern China are studied by molecular activation analysis, in which the chemical stepwise dissolution, nickel fire assay preconcentration and neutron activation analysis are jointly applied. The weighted sums of platinum group elements in 6 phases are in agreement with their total contents. The distribution patterns of platinum group elements in sulphides show that sulphide segregation is one of the important mechanisms for the fractionation of platinum group elements in upper mantle-derived material during partial melting

  10. Preliminary experimental studies on the chemical and radiation degradation of combustible plutonium contaminated material

    International Nuclear Information System (INIS)

    The chemical and radiation degradation of combustible plutonium contaminated material (PCM) in a cement matrix has been investigated. Experimental studies have been carried out to establish the influence of any water soluble chemical and radiation degradation products on the solubility of plutonium at high pHs. The influence of complexing agents (e.g. EDTA, citric acid), which may be present in wastes, on plutonium solubility has been assessed. The extent of sorption on cement in the presence of organic degradation products has been measured. (author)

  11. Gas-Phase Molecular Dynamics: Theoretical Studies In Spectroscopy and Chemical Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Yu H. G.; Muckerman, J.T.

    2012-05-29

    The main goal of this program is the development and application of computational methods for studying chemical reaction dynamics and molecular spectroscopy in the gas phase. We are interested in developing rigorous quantum dynamics algorithms for small polyatomic systems and in implementing approximate approaches for complex ones. Particular focus is on the dynamics and kinetics of chemical reactions and on the rovibrational spectra of species involved in combustion processes. This research also explores the potential energy surfaces of these systems of interest using state-of-the-art quantum chemistry methods, and extends them to understand some important properties of materials in condensed phases and interstellar medium as well as in combustion environments.

  12. Selected bibliography for the extraction of uranium from seawater: chemical process and plant design feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Binney, S.E.; Polkinghorne, S.T.; Jante, R.R.; Rodman, M.R.; Chen, A.C.T.; Gordon, L.I.

    1979-02-01

    A selected annotated bibliography of 521 references was prepared as a part of a feasibility study of the extraction of uranium from seawater. For the most part, these references are related to the chemical processes whereby the uranium is removed from the seawater. A companion docment contains a similar bibliography of 471 references related to oceanographic and uranium extraction plant siting considerations, although some of the references are in common. The bibliography was prepared by computer retrieval from Chemical Abstracts, Nuclear Science Abstracts, Energy Data Base, NTIS, and Oceanic Abstracts. References are listed by author, country of author, and selected keywords.

  13. Selected bibliography for the extraction of uranium from seawater: chemical process and plant design feasibility study

    International Nuclear Information System (INIS)

    A selected annotated bibliography of 521 references was prepared as a part of a feasibility study of the extraction of uranium from seawater. For the most part, these references are related to the chemical processes whereby the uranium is removed from the seawater. A companion docment contains a similar bibliography of 471 references related to oceanographic and uranium extraction plant siting considerations, although some of the references are in common. The bibliography was prepared by computer retrieval from Chemical Abstracts, Nuclear Science Abstracts, Energy Data Base, NTIS, and Oceanic Abstracts. References are listed by author, country of author, and selected keywords

  14. Equiangular Frames and Signature Sets

    CERN Document Server

    Singh, Preeti

    2009-01-01

    We will present a relation between real equiangular frames and certain special sets in groups which we call signature sets and show that many equiangular frames arise in this manner. Then we will define quasi-signature sets and will examine equiangular frames associated to these subsets of groups. We will extend these results to complex equiangular frames where the inner product between any pair of vectors is a common multiple of a cube root of unity and exhibit equiangular frames that arise from groups in this manner.

  15. Biodegradation reduces magnetization in oil bearing rocks: magnetization results of a combined chemical and magnetic study

    Science.gov (United States)

    Emmerton, S.; Muxworthy, A. R.; Sephton, M. A.; Williams, W.

    2012-12-01

    A relationship between hydrocarbons and their magnetic signatures has been alluded to for decades but this is the first study to combine geochemical and magnetic data. We report an extended study that identifies a definitive connection between magnetic mineralogy and biodegradation within oil-bearing rocks. Samples from Colombia, Canada Indonesia and the UK were collected and magnetically characterized. A negative linear regression in log space between magnetic susceptibility and the percentage of extractable organic matter was observed for individual reservoirs. To determine if this relationship is due to the activity of bacteria or migration of the oil, the percentage of oil components; aliphatic, aromatics, polars and resins and the biodegradation state of the samples were compared to the magnetic susceptibility and magnetic mineralogy of the samples. Geochemical biomarker data revealed that all oil samples were derived from mature type-II kerogen, which was deposited in oxygen-poor environments allowing for an investigation into biodegradation variations. Biodegradation is the decrease of oil quality through the conversion of aliphatic hydrocarbons to polar constituents mainly through the activity of bacteria. A distinct decrease in magnetic susceptibility was correlated to decreasing oil quality (loss of aliphatic hydrocarbons, more biodegraded), which cannot be rejected at 99% confidence. Further magnetic characterization revealed that the high quality, low biodegradation oils from Colombia have a higher magnetic susceptibility (10-3-10-4 m3kg-1) and are dominated by pseudo-single domain grains of magnetite. The lower quality oils i.e., the UK, Canadian and Indonesian samples, displayed decreased magnetic susceptibility (10-5-10-6 m3kg-1) and pseudo-single domain to multidomain grains of magnetite and hematite. Magnetite and pyrrhotite framboidal material were found in all but the Canadian samples. Therefore, with decreasing oil quality there is a progressive

  16. A Signature Scheme with Non-Repudiation

    Institute of Scientific and Technical Information of China (English)

    XIN Xiangjun; GUO Xiaoli; XIAO Guozhen

    2006-01-01

    Based on the Schnorr signature scheme, a new signature scheme with non-repudiation is proposed. In this scheme, only the signer and the designated receiver can verify the signature signed by the signer, and if necessary, both the signer and the designated receiver can prove and show the validity of the signature signed by the signer. The proof of the validity of the signature is noninteractive and transferable. To verify and prove the validity of the signature, the signer and the nominated receiver needn't store extra information besides the signature. At the same time, neither the signer nor the designated receiver can deny a valid signature signed. Then, there is no repudiation in this new signature scheme. According to the security analysis of this scheme, it is found the proposed scheme is secure against existential forgery on adaptive chosen message attack.

  17. Comparative study of chemical cold agglomeration between two Brazilian phosphate fines: Patos de Minas and Catalao-Go, Brazil

    International Nuclear Information System (INIS)

    The viability for using the phosphoric acid as chemical binder for agglomeration of phosphate fines from Catalao, Brazil, based on the good results obtained for pelletizing phosphate fines from Patos de Minas, is studied. The granulometric and chemical characterizations by fluorescence spectrometry and X-ray diffraction were done. The results presented different physical and chemical properties, even thus the phosphoric acid could be used with advantages for chemical agglomeration of phosphate fines from Catalao. (author)

  18. Lycopersicon assays of chemical/radiation genotoxicity for the study of environmental mutagens.

    Science.gov (United States)

    Grant, William F; Owens, Elizabeth T

    2002-07-01

    From a literature survey, 21 chemicals are tabulated that have been evaluated in 39 assays for their clastogenic effects in Lycopersicon. Nineteen of the 21 chemicals are reported as giving a positive reaction (i.e. causing chromosome aberrations). Of these, five are reported positive with a dose response. In addition, 23 assays have been recorded for six types of radiation, all of which reacted positively. The results of 102 assays with 32 chemicals and seven types of radiation tested for the induction of gene mutations are tabulated, as well as 20 chemicals and/or radiation in combined treatments. The Lycopersicon esculentum (2n=24) assay is a very good plant bioassay for assessing chromosome damage both in mitosis and meiosis and for somatic mutations induced by chemicals and radiations. The Lycopersicon bioassay has been shown to be as sensitive and as specific an assay as other plant genotoxicity assays, such as Hordeum vulgare, Vicia faba, Crepis capillaris, Pisum sativum and Allium cepa and should be considered in further studies in assessing clastogenicity. Tests using L. esculentum can be made for a spectrum of mutant phenotypes of which many are identifiable in young seedlings. PMID:12088718

  19. Experimental studies of thermal and chemical interactions between molten aluminum and water

    Energy Technology Data Exchange (ETDEWEB)

    Farahani, A.A.; Corradini, M.L. [Univ. of Wisconsin, Madison, WI (United States)

    1995-09-01

    The possibility of rapid physical and chemical aluminum/water interactions during a core melt accident in a noncommercial reactor (e.g., HFIR, ATR) has resulted in extensive research to determine the mechanism by which these interactions occur and propagate on an explosive time scale. These events have been reported in nuclear testing facilities, i.e., during SPERT 1D experiment, and also in aluminum casting industries. Although rapid chemical reactions between molten aluminum and water have been subject of many studies, very few reliable measurements of the extent of the chemical reactions have thus far been made. We have modified an existing 1-D shock tube facility to perform experiments in order to determine the extent of the explosive thermal/chemical interactions between molton aluminum and water by measuring important physical quantities such as the maximum dynamic pressure and the amount of the generated hydrogen. Experimental results show that transient pressures greater than 69 MPa with a rise time of less than 125 {mu}sec can occur as the result of the chemical reaction of 4.2 grams of molton aluminum (approximately 15% of the total mass of the fuel of 28 grams) at 980 C with room temperature water.

  20. Rapid continuous chemical methods for studies of nuclei far from stability

    CERN Document Server

    Trautmann, N; Eriksen, D; Gaggeler, H; Greulich, N; Hickmann, U; Kaffrell, N; Skarnemark, G; Stender, E; Zendel, M

    1981-01-01

    Fast continuous separation methods accomplished by combining a gas-jet recoil-transport system with a variety of chemical systems are described. Procedures for the isolation of individual elements from fission product mixtures with the multistage solvent extraction facility SISAK are presented. Thermochromatography in connection with a gas-jet has been studied as a technique for on-line separation of volatile fission halides. Based on chemical reactions in a gas-jet system itself separation procedures for tellurium, selenium and germanium from fission products have been worked out. All the continuous chemical methods can be performed within a few seconds. The application of such procedures to the investigation of nuclides far from the line of beta -stability is illustrated by a few examples. (16 refs).

  1. Shock-induced solid-state chemical reactivity studies using time-resolved radiation pyrometry

    International Nuclear Information System (INIS)

    Time-resolved radiation pyrometry has been used to study materials which undergo solid-state chemical reactions due to shock loading. Shock-induced chemical reactivity in solids is fundamentally different than that in high explosives and other energetic materials because, if no volatiles are present, the reaction products end up in the condensed, rather than the vapor, state. Bulk property changes accompanying the solid-state reactions may therefore be too small to be observable with wave profile or shock-velocity measurements. However, some solid-state reactions, such as that between metallic nickel and aluminum, are exothermic enough to give rise to a measurable increase in temperature, so pyrometry can be used to detect the reactions. Unfortunately, these measurements are complicated by the large temperature increases generated by other sources. Possible mechanisms for generation of these high temperatures, and their effect on the chemical reaction, are suggested

  2. Isotope effects on chemical shifts in the study of intramolecular hydrogen bonds

    DEFF Research Database (Denmark)

    Hansen, Poul Erik

    2015-01-01

    The paper deals with the use of isotope effects on chemical shifts in characterizing intramolecular hydrogen bonds. Both so-called resonance-assisted (RAHB) and non-RAHB systems are treated. The importance of RAHB will be discussed. Another very important issue is the borderline between “static......” and tautomeric systems. Isotope effects on chemical shifts are particularly useful in such studies. All kinds of intramolecular hydrogen bonded systems will be treated, typical hydrogen bond donors: OH, NH, SH and NH+, typical acceptors C=O, C=N, C=S C=N−. The paper will be deal with both secondary...... and primary isotope effects on chemical shifts. These two types of isotope effects monitor the same hydrogen bond, but from different angles...

  3. Isotopic and chemical studies of geothermal waters of Northern Areas in Pakistan

    International Nuclear Information System (INIS)

    Northern Areas is one of the major thermal fields of Pakistan with more than two dozen known hot springs having discharge temperature ranging from 35 deg. C to 94 deg. C. Isotopic and chemical techniques applied to study the geothermal fields show that thermal waters are of meteoric origin and can be classified as Na-HCO3, Na-SO4 and mixed type on the basis of their chemical contents. At some places cooling of thermal waters seems to be due to steam separation whereas mixing with fresh cold water is prominent at the remaining sites. The temperatures estimated by isotopic and chemical geothermometers for the two major fields i.e. Tatta Pani and Murtazabad are 83-257 deg. C and 65-296 deg. C respectively. (author). 24 refs, 11 figs, 3 tabs

  4. Constraining blazar physics with polarization signatures

    Science.gov (United States)

    Zhang, Haocheng; Boettcher, Markus; Li, Hui

    2016-01-01

    Blazars are active galactic nuclei whose jets are directed very close to our line of sight. They emit nonthermal-dominated emission from radio to gamma-rays, with the radio to optical emissions known to be polarized. Both radiation and polarization signatures can be strongly variable. Observations have shown that sometimes strong multiwavelength flares are accompanied by drastic polarization variations, indicating active participation of the magnetic field during flares. We have developed a 3D multi-zone time-dependent polarization-dependent radiation transfer code, which enables us to study the spectral and polarization signatures of blazar flares simultaneously. By combining this code with a Fokker-Planck nonthermal particle evolution scheme, we are able to derive simultaneous fits to time-dependent spectra, multiwavelength light curves, and time-dependent optical polarization signatures of a well-known multiwavelength flare with 180 degree polarization angle swing of the blazar 3C279. Our work shows that with detailed consideration of light travel time effects, the apparently symmetric time-dependent radiation and polarization signatures can be naturally explained by a straight, helically symmetric jet pervaded by a helical magnetic field, without the need of any asymmetric structures. Also our model suggests that the excess in the nonthermal particles during flares can originate from magnetic reconnection events, initiated by a shock propagating through the emission region. Additionally, the magnetic field should generally revert to its initial topology after the flare. We conclude that such shock-initiated magnetic reconnection event in an emission environment with relatively strong magnetic energy can be the driver of multiwavelength flares with polarization angle swings. Future statistics on such observations will constrain general features of such events, while magneto-hydrodynamic simulations will provide physical scenarios for the magnetic field evolution

  5. Infra-sound Signature of Lightning

    Science.gov (United States)

    Arechiga, R. O.; Badillo, E.; Johnson, J.; Edens, H. E.; Rison, W.; Thomas, R. J.

    2012-12-01

    We have analyzed thunder from over 200 lightning flashes to determine which part of thunder comes from the gas dynamic expansion of portions of the rapidly heated lightning channel and which from electrostatic field changes. Thunder signals were recorded by a ~1500 m network of 3 to 4 4-element microphone deployed in the Magdalena mountains of New Mexico in the summers of 2011 and 2012. The higher frequency infra-sound and audio-range portion of thunder is thought to come from the gas dynamic expansion, and the electrostatic mechanism gives rise to a signature infra-sound pulse peaked at a few Hz. More than 50 signature infra-sound pulses were observed in different portions of the thunder signal, with no preference towards the beginning or the end of the signal. Detection of the signature pulse occurs sometimes only for one array and sometimes for several arrays, which agrees with the theory that the pulse is highly directional (i.e., the recordings have to be in a specific position with respect to the cloud generating the pulse to be able to detect it). The detection of these pulses under quiet wind conditions by different acoustic arrays corroborates the electrostatic mechanism originally proposed by Wilson [1920], further studied by Dessler [1973] and Few [1985], observed by Bohannon [1983] and Balachandran [1979, 1983], and recently analyzed by Pasko [2009]. Pasko employed a model to explain the electrostatic-to-acoustic energy conversion and the initial compression waves in observed infrasonic pulses, which agrees with the observations we have made. We present thunder samples that exhibit signature infra-sound pulses at different times and acoustic source reconstruction to demonstrate the beaming effect.

  6. New particles and their experimental signatures

    International Nuclear Information System (INIS)

    This report summarizes work done by our theoretical working group on exotic particles before, during and since the Lausanne meeting. We discuss the motivations, rates and experimental signatures for new physics and new particles in the 1 TeV mass range. Section 2 reviews some of the motivations for expecting new physics in this range. Of particular interest is the physics of gauge symmetry breaking. In section 3 we discuss the rates and experimental signatures of new particles predicted by theoretical models of gauge symmetry breaking, notably the Higgs boson supersymmetry and technicolour. Among the signatures we discuss are multiple Wsup(+-) and/or Z0 events (for the Higgs), missing transverse energy (for supersymmetry) and multiple anti tt events (for the Higgs and technicolour). We provide many examples of final state differential distributions in rapidity and Psub(T), particularly for Higgses and for supersymmetry. We also analyse some physics backgrounds to the new particle production processes which interest us. Examples include W+W-, Z0Z0, W(anti tt) and (anti tt) production as backgrounds to Higgs production. However, we do not consider in detail non-physics backgrounds such as the jet fluctuation background to missing energy signals for supersymmetry production. Section 4 summarizes our preliminary conclusions on the observability at a high energy hadron collider of the new particles studied in this report. (orig./HSI)

  7. Equilibrium and thermodynamic studies of Cd (II) biosorption by chemically modified orange peel.

    Science.gov (United States)

    Kumar, Arbind; Kumar, Vipin

    2016-03-01

    Agricultural wastes have great potential of removing heavy metal ions from aqueous solution. Removal of Cd (II) from aqueous solutions onto chemically modified orange peel was studied at different pH, contact time, initial metal concentrations, adsorbent doses and temperature. Batch experiments were carried out under optimized conditions to evaluate the adsorption capacity of orange peel chemically modified with NaOH. The results showed that maximum adsorption capacity of modified orange peel, approximately 97.0%, was observed 3 mg 1⁻¹ of initial Cd(II) concentration pH 6 for 4 g 1⁻¹ adsorbent dosage, 200 min contact time and 298 K temperature. Adsorption efficiency of modified orange peel decreased with increase in temperature indicated exothermic nature of adsorption. A negative value of ΔG⁰(-8.59 kJ mol⁻¹) confirmed the feasibility of adsorption process and spontaneous nature of adsorption. A negative value of ΔH⁰ (-28.08 kJ mol⁻¹) indicated exothermic nature while a negative ΔS⁰ (-66.86 J K⁻¹ mol⁻¹) value suggested decrease in degree of freedom of the adsorbed species. The results showed that biosorption process of Cd(II) ions by chemically modified orange peel is feasible, spontaneous and exothermic under studied conditions. Chemically by modified orange peel investigated in the present study showed good potential for the removal of cadmium from aqueous solutions. PMID:27097438

  8. Patterns of chemical use and exposure control in the Semiconductor Health Study.

    Science.gov (United States)

    Hallock, M F; Hammond, S K; Hines, C J; Woskie, S R; Schenker, M B

    1995-12-01

    Information on chemical use and exposure control between 1986 and 1990 was collected from 14 companies participating in the Semiconductor Health Study. Questionnaires and site visits provided data used to develop exposure categories for three epidemiological studies: prospective, historical, and cross-sectional. Patterns of use of target chemicals were compiled for 82 silicon-wafer fabrication rooms (fabs), including 47 from which subjects were selected for study. Chemical use was examined by operation, year, and epidemiological component. Target agents for epidemiological analyses were present in more than 50% of fabs. Use of these agents was fairly constant from 1986 to 1990, except for a moderate increase in use of propylene glycol monomethyl ether acetate, a solvent being substituted for ethylene-based glycol ethers (EGE) in photoresists. The distribution of personal protective equipment, engineering controls, and other factors potentially affecting employee exposure was also examined. Controls designed to manage processes or high acute toxicity were present in most fabs; their prevalence remained unchanged from 1986 through 1990. Controls designed to reduce exposures to chemicals with low acute toxicity were less widely distributed; their prevalence increased moderately from 1986 to 1990. PMID:8588557

  9. Gene expression signatures for colorectal cancer microsatellite status and HNPCC

    DEFF Research Database (Denmark)

    Kruhøffer, M; Jensen, J L; Laiho, P;

    2005-01-01

    is correlated to prognosis and response to chemotherapy. Gene expression signatures as predictive markers are being developed for many cancers, and the identification of a signature for MMR deficiency would be of interest both clinically and biologically. To address this issue, we profiled the gene...... expression of 101 stage II and III colorectal cancers (34 MSI, 67 microsatellite stable (MSS)) using high-density oligonucleotide microarrays. From these data, we constructed a nine-gene signature capable of separating the mismatch repair proficient and deficient tumours. Subsequently, we demonstrated the......-deficient tumours into sporadic MSI and HNPCC cases, and validated this by a mathematical cross-validation approach. The demonstration that this two-step classification approach can identify MSI as well as HNPCC cases merits further gene expression studies to identify prognostic signatures....

  10. Gene expression profiles identify inflammatory signatures in dendritic cells.

    Directory of Open Access Journals (Sweden)

    Anna Torri

    Full Text Available Dendritic cells (DCs constitute a heterogeneous group of antigen-presenting leukocytes important in activation of both innate and adaptive immunity. We studied the gene expression patterns of DCs incubated with reagents inducing their activation or inhibition. Total RNA was isolated from DCs and gene expression profiling was performed with oligonucleotide microarrays. Using a supervised learning algorithm based on Random Forest, we generated a molecular signature of inflammation from a training set of 77 samples. We then validated this molecular signature in a testing set of 38 samples. Supervised analysis identified a set of 44 genes that distinguished very accurately between inflammatory and non inflammatory samples. The diagnostic performance of the signature genes was assessed against an independent set of samples, by qRT-PCR. Our findings suggest that the gene expression signature of DCs can provide a molecular classification for use in the selection of anti-inflammatory or adjuvant molecules with specific effects on DC activity.

  11. Chemical risk factors and childhood leukaemia: A review of recent studies

    International Nuclear Information System (INIS)

    The search for chemical risks factors as determinants of childhood leukaemia has been ongoing for over two decades. Results of epidemiological studies, published from 1998 to the present, evaluating parental smoking, outdoor sources of pollution, indoor contaminants and chemicals from drinking water are reported. Overall, results were mostly negative. This may be due to the relatively small study sizes to detect environmental effects, usually measured imprecisely. Another reason may be that such effects, which may be revealed among the genetically susceptible, have rarely accounted for genetic susceptibility. The few studies that have are also reported here. Suggestions are made for work in the immediate future, which include pooling of data and of analyses, as well as carrying out in-depth reviews of studies with the goal of understanding the reasons for discrepant results. (authors)

  12. Wild canelas from the Brazilian Northeast: botanical, chemical and pharmocological studies

    International Nuclear Information System (INIS)

    Botanical, chemical and pharmacological studies were carried out with several types of the species Croton aff. zehntneri, called 'canelas ' at the Brazilian Northeastern region. Chemical studies showed that t-anetole, estragole, and sometimes eugenole are the most common components of the essential oils of these 'canelas'. The pharmacological studies were carried out with hidroalcoholic extract, essential oil and its aqueous phase obtained during the extraction process, by means of biological assays with various laboratory animals. Results of these tests are discussed. Emphasis is given on the possibility that some of the observed effects are due to the presence of anethole and estragole in the different types of the species studied. (M.A.)

  13. In situ chemical fixation of arsenic-contaminated soils: An experimental study

    OpenAIRE

    Yang, Li; Donahoe, Rona J.; Redwine, James C.

    2007-01-01

    This paper reports the results of an experimental study testing a low-cost in situ chemical fixation method designed to reclaim arsenic-contaminated subsurface soils. Subsurface soils from several industrial sites in southeastern U.S. were contaminated with arsenic through heavy application of herbicide containing arsenic trioxide. The mean concentrations of environmentally available arsenic in soils collected from the two study sites, FW and BH, are 325 mg/kg and 900 mg/kg, respectively...

  14. Idaho Chemical Processing Plant and Plutonium-Uranium Extraction Plant phaseout/deactivation study

    International Nuclear Information System (INIS)

    The decision to cease all US Department of Energy (DOE) reprocessing of nuclear fuels was made on April 28, 1992. This study provides insight into and a comparison of the management, technical, compliance, and safety strategies for deactivating the Idaho Chemical Processing Plant (ICPP) at Westinghouse Idaho Nuclear Company (WINCO) and the Westinghouse Hanford Company (WHC) Plutonium-Uranium Extraction (PUREX) Plant. The purpose of this study is to ensure that lessons-learned and future plans are coordinated between the two facilities

  15. Galaxy interactions : The HI signature

    NARCIS (Netherlands)

    Sancisi, R; Barnes, JE; Sanders, DB

    1999-01-01

    HI observations are an excellent tool for investigating tidal interactions. Ongoing major and minor interactions which can lead to traumatic mergers or to accretion and the triggering of star formation, show distinct HI signatures. Interactions and mergers in the recent past can also be recognized i

  16. Transcriptional analysis of an E2F gene signature as a biomarker of activity of the cyclin-dependent kinase inhibitor PHA-793887 in tumor and skin biopsies from a phase I clinical study.

    Science.gov (United States)

    Locatelli, Giuseppe; Bosotti, Roberta; Ciomei, Marina; Brasca, Maria G; Calogero, Raffaele; Mercurio, Ciro; Fiorentini, Francesco; Bertolotti, Matteo; Scacheri, Emanuela; Scaburri, Angela; Galvani, Arturo; Pesenti, Enrico; De Baere, Thierry; Soria, Jean-Charles; Lazar, Vladimir; Isacchi, Antonella

    2010-05-01

    A transcriptional signature of the pan-cyclin-dependent kinase (Cdk) inhibitor PHA-793887 was evaluated as a potential pharmacodynamic and/or response biomarker in tumor and skin biopsies from patients treated in a phase I clinical study. We first analyzed the expression of a number of known E2F-dependent genes that were predicted to be modulated after Cdk2 and Cdk4 inhibition in xenograft tumor and skin samples of mice treated with the compound. This panel of 58 selected genes was then analyzed in biopsies from seven patients treated with PHA-793887 in a phase I dose escalation clinical trial in solid tumors. Quantitative real-time PCR or microarray analyses were done in paired skin and tumor biopsies obtained at baseline and at cycle 1. Analysis by quantitative real-time PCR of the signature in skin biopsies of patients treated at three different doses showed significant transcriptional downregulation with a dose-response correlation. These data show that PHA-793887 modulates genes involved in cell cycle regulation and proliferation in a clinical setting. The observed changes are consistent with its mechanism of action and correlate with target modulation in skin and with clinical benefit in tumors. PMID:20423997

  17. Phyto chemical and biological studies of certain plants with potential radioprotective activity

    International Nuclear Information System (INIS)

    One of the promising directions of radiation protection development is the search for natural radioprotective agents.The present work includes: I- Screening of certain edible and medicinal plants growing in Egypt for their radioprotective activities. II- Detailed phyto chemical and biolo-activity studies of the dried leaves of brassaia actinophylla endl. comprising: A-Phyto chemical screening and proximate analysis. B-Investigation of lipoidal matter. C- Isolation, characterization and structure elucidation of phenolic constituents. D- Isolation, characterization and structure elucidation of saponin constituents. E- Evaluation of radioprotective and antitumor activities. I- Evaluation of potential radioprotective activities of certain herbs: In vivo biological screening designed to investigate the radioprotective role of 70% ethanol extract of 11 different herbals was carried out by measuring the lipid peroxide content, as well as the activities of two antioxidant enzymes; viz glutathione, and superoxide dismutase in blood and liver tissues 1 and 7 days after radiation exposure. II : Phyto chemical and biolo-activity studies of the dried leaves of brassaia actinophylla Endl A : preliminary phyto chemical screening, determination and TLC examination of successive extractives. B : Investigation of lipoidal matter. GLC of unsaponifiable matter (USM)

  18. Studying the Permian cross-section (Volga region) using chemical and isotopic investigations

    Science.gov (United States)

    Gareev, Bulat; Georgii, Batalin; Nurgaliev, Danis; Nurgalieva, Nuriya

    2016-04-01

    This paper presents a study of international important site: the cross-section of Permian system's Urzhumian Stage in the ravine "Pechischy". Outcrop is located on the right bank of the Volga River (about 10 km West of Kazan). It has local, regional and planetary correlation features and also footprints of different geographical scale events. The main objective in the research is the deep study of sediments using chemical and isotopic investigations. XRF spectrometer was used for chemical investigations of samples. Chemistry of carbonates and clastic rocks includes the analysis of chemical elements, compounds, petrochemical (lithogeochemical) modules for the interpretation of the genesis of lithotypes. For the review of the geochemistry of stable isotopes of carbon (oxygen) we used IRMS. The main objective is the nature of the isotope fractionation issues, to addressing the issues of stratigraphy and paleogeography. The measurements have shown the variability of chemical parameters in cross-section. It gives us opportunity to see small changes in sedimentation and recognize the factors that influence to the process. The work was carried out according to the Russian Government's Program of Competitive Growth of Kazan Federal University, supported by the grant provided to the Kazan State University for performing the state program in the field of scientific research.

  19. Assessment of infant exposure to food chemicals: the French Total Diet Study design.

    Science.gov (United States)

    Hulin, M; Bemrah, N; Nougadère, A; Volatier, J L; Sirot, V; Leblanc, J C

    2014-01-01

    As part of the previous French Total Diet Studies (TDS) focusing on exposure to food chemicals in the population aged 3 years and older, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) launched a specific TDS on infants to complete its overall chemical food safety programme for the general population. More than 500 chemical substances were analysed in food products consumed by children under 3 years old, including nutrients, several endocrine disruptors resulting from human activities (polychlorinated biphenyls, dioxins and furans, brominated flame retardants, perfluoroalkyl acids, pesticide residues, etc.) or migrating from food contact materials such as bisphenol A or phthalates, but also natural substances such as mycotoxins, phytoestrogens and steroids. To obtain a representative and general view of infant food consumption, food items were selected based on results of a national consumption survey conducted specifically on this population. Moreover, a specific study on food was conducted on 429 households to determine which home-cooking practices are employed to prepare food consumed by infants. Overall, the targeted chemical substances were analysed in more than 450 food samples, representing the purchase and home-cooking practices of over 5500 food products. Foods included common foods such as vegetables, fruit or cakes as well as specific infant foods such as infant formula or jarred baby food. The sampling plan covered over 80% of the total diet. Specificities in infant food consumption and habits were therefore considered to define this first infant TDS. This study, conducted on a large scale and focusing on a particularly sensitive population, will provide accurate information on the dietary exposure of children under 3 years to food chemicals, especially endocrine disruptors, and will be particularly useful for risk assessment analysis under the remit of ANSES' expert committees. PMID:24827474

  20. UV-vis spectra of the anticancer camptothecin family drugs in aqueous solution: specific spectroscopic signatures unraveled by a combined computational and experimental study.

    Science.gov (United States)

    Sanna, Nico; Chillemi, Giovanni; Gontrani, Lorenzo; Grandi, Andrea; Mancini, Giordano; Castelli, Silvia; Zagotto, Giuseppe; Zazza, Costantino; Barone, Vincenzo; Desideri, Alessandro

    2009-04-23

    The ultraviolet-visible absorption spectrum of camptothecin (CPT) has been been recorded in aqueous solution at pH 5.3, where the equilibrium among the different CPT forms is shifted toward the lactonic one. Time-dependent density functional theory (TD-DFT) computations lead to a remarkable reproduction of the experimental spectrum only upon addition of explicit water molecules in interaction with specific moieties of the camptothecin molecule. Molecular dynamics (MD) simulations enforcing boundary periodic conditions for CPT embedded with 865 water molecules, with a force field derived from DFT computations, show that the experimental spectrum is due to the contributions of CPT molecules with different solvation patterns. A similar solvent effect is observed for several CPT derivatives, including the clinically relevant SN-38 and topotecan drugs. The quantitative agreement between TD-DFT/MD computations and experimental data allow us to identify specific spectroscopic signatures diagnostic of the drug environment and to develop procedures that can be used to monitor the drug-DNA/protein interaction. PMID:19334673

  1. Theoretical and practical aspects of chemical functionalization of carbon nanofibers (CNFs): DFT calculations and adsorption study.

    Science.gov (United States)

    Rokhina, Ekaterina V; Lahtinen, Manu; Makarova, Katerina; Jegatheesan, Veeriah; Virkutyte, Jurate

    2012-06-01

    The nitric acid-functionalized commercial carbon nanofibers (CNFs) were comprehensively studied by instrumental (XRD, BET, SEM, TGA) and theoretical (DFT calculations) methods. The detailed surface study revealed the variation in the characteristics of functionalized CNFs, such as a decreased (up to 34%) surface area and impacted structural, electronic and chemical properties. The effects of functional groups were studied by comparison with pristine nanofibers. The results showed that the C-C bond lengths of the modified CNFs varied significantly. Chemical functionalization altered the frontier orbitals of the pristine material, and therefore altered the nature of their interactions with other substances. Moreover, the pristine and modified CNFs were tested for the removal of phenol from aqueous solutions. It was observed that surface modification tuned the adsorption capacity of carbon nanofibers (up to 0.35 mmol g(-1)), whereas original fibers did not demonstrate any adsorption capacity of phenol. PMID:22209137

  2. Use of medaka as a tool in studies of radiation effects and chemical carcinogenesis

    International Nuclear Information System (INIS)

    The medaka, Oryzias latipes, a small freshwater oviparous fish, is common in Japan and found in some parts of Asia. Adult fish are 3.0-3.5 cm long and weigh 0.5-0.7 g. The small fish have been used extensively in this laboratory for analysis of radiation effects and for study of chemical carcinogenesis. These fish are relatively easy to rear and their reproductive biology is well known. Recently, inbred strains of the fish have been established by full sister-brother mating. In this report, we will review experimental results using medaka in studies of : 1) radiation effects on spermatogenesis, and 2) induction of hepatic tumors by MAM acetate, we will also review use of medaka in related studies of radiation effects and chemical carcinogenesis. (author)

  3. A study of suitability of some conventional chemical preservatives and natural antimicrobial compounds in allelopathic research

    Directory of Open Access Journals (Sweden)

    Plamen Marinov-Serafimov

    2015-12-01

    Full Text Available The impact of three conventional chemical preservatives (sodium benzoate, potassium sorbate and salicylic acid and a natural antimicrobial compound (thymol on germination, dynamics of growth and accumulation of fresh biomass (g per seedling of Lactuca sativa L., cultivar Great Lakes, was studied under laboratory conditions. The tested conventional chemical preservatives demonstrated strong inhibitory effects (GI 27.1-0.0% on germination and initial development of L. sativa, and they cannot be used in allelopathic studies in the laboratory. An addition of thymol at 0.5-1.0 ‰ concentration showed no inhibitory effect (GI varied 81.7-84.6% on germination and initial development of L. sativa. Thymol can therefore be used as a natural antimicrobial compound in allelopathic studies in the laboratory.

  4. Development of an apparatus to study chemical reactions at high temperature - a progress report

    Energy Technology Data Exchange (ETDEWEB)

    Sturzenegger, M.; Schelling, Th.; Steiner, E.; Wuillemin, D. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    TREMPER is an apparatus that was devised to study kinetic and thermodynamic aspects of high-temperature reactions under concentrated solar irradiation. The design allows investigations on solid or liquid samples under inert or reactive atmospheres. The working temperature is adjustable; the upper limit that has yet been reached is about 1900 K. TREMPER will facilitate chemical reactivity studies on a temperature level that is difficult to access by other means. First experiments were conducted to study the decomposition of manganese oxide MnO{sub 2}. Chemical analysis of exposed samples confirmed that the parent MnO{sub 2} was decomposed to mixtures of Mn O and Mn{sub 3}O{sub 4}. The amount of Mn O ranged from 60 mol-% in air to 86 mol-% under inert atmosphere. (author) 1 fig., 1 tab., 2 refs.

  5. Application of Chemical Grouting as an Option of Removing Soil Moisture - a Case Study in the Reconstruction of the Church

    Science.gov (United States)

    Katunská, Jana; Katunský, Dušan

    2015-11-01

    The article provides an analysis of removing moisture from the soil masonry walls. The chemical pressure insulation may be considered as one of the alternatives. This paper describes the chemical waterproofing and points to a case study, which is a small church in the town of Košice. Renovation of the church took place in two stages, made using pressure chemical insulation for chemical grouting of envelope masonry. The appropriateness and effectiveness of the applied chemical methods can be seen in the conclusions of this contribution.

  6. Application of Chemical Grouting as an Option of Removing Soil Moisture - a Case Study in the Reconstruction of the Church

    Directory of Open Access Journals (Sweden)

    Katunská Jana

    2015-11-01

    Full Text Available The article provides an analysis of removing moisture from the soil masonry walls. The chemical pressure insulation may be considered as one of the alternatives. This paper describes the chemical waterproofing and points to a case study, which is a small church in the town of Košice. Renovation of the church took place in two stages, made using pressure chemical insulation for chemical grouting of envelope masonry. The appropriateness and effectiveness of the applied chemical methods can be seen in the conclusions of this contribution.

  7. Chemical stimulation of gas condensate reservoirs: An experimental and simulation study

    Science.gov (United States)

    Kumar, Viren

    Well productivity in gas condensate reservoirs is reduced by condensate banking when the bottom hole flowing pressure drops below the dewpoint pressure. Several methods have been proposed to restore gas production rates after a decline due to condensate blocking. Gas injection, hydraulic fracturing, horizontal wells and methanol injection have been tried with limited success. These methods of well stimulation either offer only temporary productivity restoration or are applicable only in some situations. Wettability alteration of the rock in the near well bore region is an economic and efficient method for the enhancement of gas-well deliverability. Altering the wettability of porous media from strongly water-wet or oil-wet to intermediate-wet decreases the residual liquid saturations and results in an increase in the relative permeability to gas. Such treatments also increase the mobility and recovery of condensate from the reservoir. This study validates the above hypothesis and provides a simple and cost-efficient solution to the condensate blocking problem. Screening studies were carried out to identify the chemicals based on structure, solubility and reactivity at reservoir temperature and pressure. Experiments were performed to evaluate these chemicals to improve gas and condensate relative permeabilities. The improvement in relative permeability after chemical treatment was quantified by performing high pressure and high temperature coreflood experiments in Berea sandstone, Texas Cream limestone and reservoir cores using synthetic gas mixtures at reservoir conditions. Experiments were done at high flow rates and for long time periods to evaluate the durability of the treatment. Single well simulation studies were conducted to demonstrate the performance of the chemical treatment in the field. The experimental relative permeability data was modeled using a trapping number dependent relative permeability model and incorporated in the simulations. Effect of

  8. Elliptic Curve Blind Digital Signature Schemes

    Institute of Scientific and Technical Information of China (English)

    YOULin; YANGYixian; WENQiaoyan

    2003-01-01

    Blind signature schemes are important cryptographic protocols in guaranteeing the privacy or anonymity of the users.Three new blind signature schemes and their corresponding generalizations are pro-posed. Moreover, their securities are simply analyzed.

  9. Revisiting the use of δ15N in meso-scale studies of marine food webs by considering spatio-temporal variations in stable isotopic signatures - The case of an open ecosystem: The Bay of Biscay (North-East Atlantic)

    Science.gov (United States)

    Chouvelon, T.; Spitz, J.; Caurant, F.; Mèndez-Fernandez, P.; Chappuis, A.; Laugier, F.; Le Goff, E.; Bustamante, P.

    2012-08-01

    Most of the recent framework directives and environmental policies argue for the development and the use of indicators - notably trophodynamic indicators - that should be able to follow ecosystems' evolution in space and time, particularly under anthropogenic perturbations. In the last decades, the use of stable carbon and nitrogen isotopes ratios has increased exponentially, particularly in studies of marine ecosystems' trophic structure and functioning. This method is principally based on the assumption that the isotopic composition of a consumer directly reflects that of its food. Nevertheless, few studies have attempted to define the limits of this tool, before using it and drawing ecological conclusions from isotopic analysis. This study aimed to assess the importance of considering spatio-temporal variations in isotopic signatures of consumers when using δ13C and especially δ15N values in open ecosystems with complex food webs, using the Bay of Biscay (North-East Atlantic) as a case study. To this end, more than 140 species from this marine ecosystem were analysed for the isotopic signatures in their muscle tissue. They were sampled from coastal to oceanic and deep-sea areas and at different latitudes, to evaluate spatial variations of isotopic signatures. Selected species were also sampled over several years and in two seasons to account for inter-annual and seasonal variations. In the Bay of Biscay temperate ecosystem, which is subject to both coastal and oceanic influences - two main river inputs and upwelling areas - , δ13C and δ15N values significantly decreased from inshore to offshore species, and to a lesser extent from benthic to pelagic organisms. River discharges appeared to be the first factor influencing δ13C and δ15N values in consumers. From the important spatial variations detected in δ15N values in particular, we suggest that in such contrasted ecosystem, nitrogen isotopic ratios may also be revisited as an indicator of the feeding

  10. Multilepton Signatures for Leptoquarks

    OpenAIRE

    Eboli, O. J. P.; Funchal, R. Z.; Lungov, T. L.

    1998-01-01

    The production of third generation leptoquarks can give rise to multilepton events accompanied by jets and missing transverse energy. In this work we study the signals of these leptoquarks at the CERN Large Hadron Collider and compare them with the ones expected in supersymmetric models.

  11. Assessment of chemicals using a battery of neurobehavioral tests: a comparative study.

    Science.gov (United States)

    Pryor, G T; Uyeno, E T; Tilson, H A; Mitchell, C L

    1983-01-01

    Single-dose LD10S and LD50S were determined in male, Fischer-344 rats for acrylamide monomer, arsenic trioxide, chlordecone, lead acetate, methylmercury hydroxide, monosodium salicylate, tetraethyl tin, and triethyl lead chloride. Proportions of the single-dose LD10S were used in a subacute study to estimate the 28-day LD20S for each chemical. Proportions of the 28-day LD20S were used in a subchronic (105 days of dosing) study to determine the effectiveness of a battery of neurobehavioral tests for detecting and characterizing the neurotoxic effects of each chemical. The battery consisted of undifferentiated motor activity, forelimb and hindlimb grip strengths, rotation orientation, thermal sensitivity, startle responsiveness to acoustic and air-puff stimuli, and performance of a multisensory conditioned pole-climb avoidance response task; body weight and rectal temperature were also monitored. The battery of tests was administered on eight occasions, that is, before, at three-week intervals during dosing (PO or IP, five days each week for 15 weeks), and at three and six weeks after dosing. Normative data (controls from each experiment) indicated fair overall stability of the measures over the eight test sessions, but experiment-to-experiment variability in this regard was clearly evident. The inherent statistical sensitivity of the tests varied greatly as estimated by their coefficients of variation, which ranged from 1% (rectal temperature) to over 100% (rotation orientation). Intercorrelations among the various measures were low to moderate indicating relatively little redundancy. The various measures were differentially affected by the eight chemicals: body weight by all eight; rectal temperature by one; undifferentiated motor activity by three; forelimb grip strength by two; hindlimb grip strength by four; rotation orientation by one; thermal sensitivity by one; startle responsiveness by three; and CAR performance by five. A profile analysis using the slopes

  12. Study about the integrated treatment of chemical and radioactive effluents, introducing the zero release concept

    International Nuclear Information System (INIS)

    An Integrated System to the treatment of Chemical and Radioactive Effluents to the Centro Experimental Aramar is proposed and evaluated, introducing the Effluent Zero Release concept, where factors related to the environmental regulation in vigor in the country, as well as the availability of hydrological resources in the place where CEA have been implanted, are considered. Through a literature analysis of the main effluents treatment techniques available nowadays and after a case of study selection, take into account two industrial installations that will be implanted at CEA, it was defined an arrangement to compose the Integrated System to the Treatment of Chemicals and Radioactive Effluents, focusing the Zero Release concept consolidation. A defined arrangement uses a combination among three treatment processes, it means chemical precipitation, reverse osmosis and evaporation, that were experimentally evaluated. The proposed arrangement was evaluated using synthetic effluents, that were prepared based on data from literature and conception documents of the installation considered in this work. Three kinds of effluents were simulated, one arising from a nuclear reactor laundry, one arising from the water refrigeration system and demineralized water production to the nuclear reactor and the other one arising from a nuclear material production laboratory. Each effluent were individually submitted to the selected treatment processes, to get the best operational conditions for each treatment process. The results got during the laboratory assays show that the proposed Integrated System to the Treatment of Chemicals and Radioactive Effluents is feasible, consolidating the Effluent Zero Release concept, which is the proposition of this work. (author)

  13. Supervised extensions of chemography approaches: case studies of chemical liabilities assessment.

    Science.gov (United States)

    Ovchinnikova, Svetlana I; Bykov, Arseniy A; Tsivadze, Aslan Yu; Dyachkov, Evgeny P; Kireeva, Natalia V

    2014-01-01

    Chemical liabilities, such as adverse effects and toxicity, play a significant role in modern drug discovery process. In silico assessment of chemical liabilities is an important step aimed to reduce costs and animal testing by complementing or replacing in vitro and in vivo experiments. Herein, we propose an approach combining several classification and chemography methods to be able to predict chemical liabilities and to interpret obtained results in the context of impact of structural changes of compounds on their pharmacological profile. To our knowledge for the first time, the supervised extension of Generative Topographic Mapping is proposed as an effective new chemography method. New approach for mapping new data using supervised Isomap without re-building models from the scratch has been proposed. Two approaches for estimation of model's applicability domain are used in our study to our knowledge for the first time in chemoinformatics. The structural alerts responsible for the negative characteristics of pharmacological profile of chemical compounds has been found as a result of model interpretation. PMID:24868246

  14. Double-focusing mixing jet for XFEL study of chemical kinetics

    International Nuclear Information System (INIS)

    A novel method for time-resolved study of chemical kinetics using a windowless mixing jet at an X-ray free-electron laser (XFEL) is described and demonstrated. The short mixing time gives a time resolution of about 250 µs; the design introduces controllable delays after the initiation of a chemical reaction, allowing the possibility for detection of transient structures by an XFEL beam pulse. Applications may include time-resolved enzyme–substrate imaging or protein folding. Several liquid sample injection methods have been developed to satisfy the requirements for serial femtosecond X-ray nanocrystallography, which enables radiation-damage-free determination of molecular structure at room temperature. Time-resolved nanocrystallography would combine structure analysis with chemical kinetics by determining the structures of the transient states and chemical kinetic mechanisms simultaneously. A windowless liquid mixing jet device has been designed for this purpose. It achieves fast uniform mixing of substrates and enzymes in the jet within 250 µs, with an adjustable delay between mixing and probing by the X-ray free-electron laser beam of up to 1 s for each frame of a ‘movie’. The principle of the liquid mixing jet device is illustrated using numerical simulation, and experimental results are presented using a fluorescent dye

  15. Blind Signature Scheme Based on Chebyshev Polynomials

    Directory of Open Access Journals (Sweden)

    Maheswara Rao Valluri

    2011-12-01

    Full Text Available A blind signature scheme is a cryptographic protocol to obtain a valid signature for a message from a signer such that signer’s view of the protocol can’t be linked to the resulting message signature pair. This paper presents blind signature scheme using Chebyshev polynomials. The security of the given scheme depends upon the intractability of the integer factorization problem and discrete logarithms ofChebyshev polynomials.

  16. Enhancing the functionality of cotton fabric by physical and chemical pre-treatments: A comparative study.

    Science.gov (United States)

    Gargoubi, Sondes; Tolouei, Ranna; Chevallier, Pascale; Levesque, Lucie; Ladhari, Neji; Boudokhane, Chedly; Mantovani, Diego

    2016-08-20

    Recently, antimicrobial and decontaminating textiles, such as cotton a natural carbohydrate polymer, are generating more attention. Plant materials used for natural dyes are expected to impart biofunctional properties and high added valued functional textiles. In the current study, surface modification of cotton to maximize the dye amount on the surface has been investigated. Physical modification using nitrogen-hydrogen plasma, chemical modification using chitosan and chemical modification using dopamine as biopolymers imparting amino groups were explored. Furthermore, dye exhaustion of curcumin, as a natural functional dye has been studied. Dye stability tests were also performed after fabric washing using hospital washing protocol to predict the durability of the functionalizations. The results demonstrated that cotton surfaces treated with dopamine exhibit a high level of dye uptake (78%) and a good washing fastness. The use of non-toxic and natural additives during cotton finishing process could give the opportunity of cradle to cradle design for antimicrobial textile industries. PMID:27178905

  17. The use of sugarcane bagasse ash as an alternative local pozzolanic material: study of chemical composition

    International Nuclear Information System (INIS)

    The sugarcane bagasse ash is used as fuel in the boilers of the Kinana sugar factory in Sudan. The field observation and qualitative study of the ash revealed that it consisted of major amounts of carbon and organic materials; this is due to the incomplete combustion of bagasse fibers in boilers. Therefore, it became necessary to recondition the samples for use as pozzolana by re-ashing it. The study of chemical composition of the ash revealed that such byproducts are likely to be pozzolanic. Comparison between chemical compositions of Kinana sugarcane bagasse ash and the pulverized coal fly ashes (ASTM C 618 1999) shows that the composition of bagasse resembles that of Class F Coal Fly Ash, as the total of alumina, silica, and ferric oxide content is about 72 %. It may, behave like Class F Fly Ash, in its engineering properties. (author)

  18. Chemical compatibility study of melilite-type gallate solid electrolyte with different cathode materials

    Science.gov (United States)

    Mancini, Alessandro; Felice, Valeria; Natali Sora, Isabella; Malavasi, Lorenzo; Tealdi, Cristina

    2014-05-01

    Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La1.50Sr0.50Ga3O7.25 has been extensively investigated by X-ray powder diffraction in a wide temperature range (up to 1573 K). Perovskite-type La0.8Sr0.2MnO3-d and La0.8Sr0.2Fe0.8Cu0.2O3-d and K2NiF4-type La2NiO4+d were selected as cathode materials. The results of this study allow identifying the most suitable electrode material to be used in combination with the melilite-type gallate electrolyte and set the basis for future work on this novel system.

  19. Study of the chemical behaviour of technetium during irradiated fuels reprocessing

    International Nuclear Information System (INIS)

    This paper deals with the preparation of the lower oxidation states +III +IV and +V of technetium in nitric acid and its behaviour during the reprocessing of nuclear fuels (PUREX process). The first part of this work is a bibliographical study of this element in solution without any strong ligand. By chemical and electrochemical technics, pentavalent, tetravalent and trivalent technetium species, were prepared in nitric acid. The following chemical reactions are studied: - trivalent and tetravalent technetium oxidation by nitrate ion. - hydrazine and tetravalent uranium oxidation catalysed by technetium: in those reactions, we point out unequivocally the prominent part of trivalent and tetravalent technetium, - technetium behaviour towards hydroxylamine. Technetium should not cause any disturbance in the steps where hydroxylamine is employed to destroy nitrous acid and hydrazine replacement by hydroxylamine in uranium-plutonium partition could contribute to a best reprocessing of nuclear fuels

  20. A detailed comparative study between chemical and bioactive properties of Ganoderma lucidum from different origins.

    Science.gov (United States)

    Stojković, Dejan S; Barros, Lillian; Calhelha, Ricardo C; Glamočlija, Jasmina; Ćirić, Ana; van Griensven, Leo J L D; Soković, Marina; Ferreira, Isabel C F R

    2014-02-01

    A detailed comparative study on chemical and bioactive properties of wild and cultivated Ganoderma lucidum from Serbia (GS) and China (GCN) was performed. This species was chosen because of its worldwide use as medicinal mushroom. Higher amounts of sugars were found in GS, while higher amounts of organic acids were recorded in GCN. Unsaturated fatty acids predominated over saturated fatty acids. GCN revealed higher antioxidant activity, while GS exhibited inhibitory potential against human breast and cervical carcinoma cell lines. No cytotoxicity in non-tumour liver primary cell culture was observed for the different samples. Both samples possessed antibacterial and antifungal activities, in some cases even better than the standard antimicrobial drugs. This is the first study reporting a comparison of chemical compounds and bioactivity of G. lucidum samples from different origins. PMID:24020451

  1. CDIO Projects in DTU’s Chemical and Biochemical B.Eng. Study Program

    DEFF Research Database (Denmark)

    Clement, Karsten; Harris, Pernille; Agersø, Yvonne

    2011-01-01

    The aim of this paper is to describe how the CDIO standards [1] have influenced the cross-disciplinary projects that are part of the study plan for the Chemical and Biochemical B.Eng. program. Four projects are described: The 1st semester design-build project on cleaning of waste water from a pow...... plant, the 2nd semester laboratory project concerning antimicrobial resistant E. coli bacteria in retail meats, the 3rd semester project on unit operations in enzyme production, the 4th semester project on the fermentation and purification part of enzyme production.......The aim of this paper is to describe how the CDIO standards [1] have influenced the cross-disciplinary projects that are part of the study plan for the Chemical and Biochemical B.Eng. program. Four projects are described: The 1st semester design-build project on cleaning of waste water from a power...

  2. Molecular dynamics study of phase separation in fluids with chemical reactions

    Science.gov (United States)

    Krishnan, Raishma; Puri, Sanjay

    2015-11-01

    We present results from the first d =3 molecular dynamics (MD) study of phase-separating fluid mixtures (AB) with simple chemical reactions (A ⇌B ). We focus on the case where the rates of forward and backward reactions are equal. The chemical reactions compete with segregation, and the coarsening system settles into a steady-state mesoscale morphology. However, hydrodynamic effects destroy the lamellar morphology which characterizes the diffusive case. This has important consequences for the phase-separating structure, which we study in detail. In particular, the equilibrium length scale (ℓeq) in the steady state suggests a power-law dependence on the reaction rate ɛ :ℓeq˜ɛ-θ with θ ≃1.0 .

  3. Study physico-chemical of the sand of the western ERG (Western South Algeria)

    Energy Technology Data Exchange (ETDEWEB)

    Allam, M.; Tafraoui, A. [Faculty of sciences and technology, University of Bechar (Algeria)], email: allammessaouda@yahoo.fr

    2011-07-01

    Silica is gaining increasing importance as it is the base for the production of pure silicon, for which several applications are under development in the electronic and solar energy sectors. The aim of this study is to characterize the sand taken from the Western Erg of Algeria to determine the percentage of silicon it contains. Characterization was done through physical analysis to determine the granulometry of the sand. A chemical analysis was next performed, using diffraction of X-rays and a scanning electron microscope to determine the chemical composition of the sand. Results showed that the sand is mainly made of quartz in the form of rounded and subbarrondis grains and that silicon is prevalent, accounting for 98% of the composition. This study demonstrated that sand from the Western Erg of Algeria is rich in silicon and could be used for silicon production.

  4. Signatures of Topological Defects

    OpenAIRE

    Berezinsky, V. S.; P. Blasi(INAF Arcetri); Vilenkin, A.

    1998-01-01

    We argue that due to various restrictions cosmic strings and monopole-string networks are not likely to produce the observed flux of ultra-high energy cosmic rays (UHECR). Among the topological defects studied so far, the most promising UHECR sources are necklaces and monopolonia. Other viable sources which are similar to topological defects are relic superheavy particles. All these sources have an excess of pions (and thus photons) over nucleons at production. We demonstrate that in the case...

  5. Studies on fuel-clad chemical interaction of U-10Zr alloy with T91 cladding

    International Nuclear Information System (INIS)

    Fuel-clad chemical compatibility has been recognized as one of the major concerns about the performance of metallic fuel since it limits the life of the fuel pin due to formation of low melting eutectic. The fuel-clad compatibility between U-10Zr and T91 was studied by diffusion couple experiments at normal operating and transient conditions. The diffusion reaction between these two was strongly retarded due to formation of a Zr-rich layer at the interface. (author)

  6. Studies of chemical and enzymatic characteristics of Yacon (Smallanthus sonchifolius) and its flours

    OpenAIRE

    Juciane de Abreu Ribeiro Pereira; Maria de Fátima Píccolo Barcelos; Michel Cardoso de Angelis Pereira; Eric Batista Ferreira

    2013-01-01

    Due to the importance of studies on yacon related to health, its in natura pulp, in natura peel, pulp flour, and peel flour were chemically analyzed in terms of its centesimal composition, specific minerals, total dietary fiber and fractions, pH, total soluble solids, total titratable acidity, tannins, oxalic acid, and nitrate. The polyphenoloxidase and peroxidase enzymatic activities were evaluated for in natura pulp and peel only. Yacon pulp and peel flour presented average yield of 7.94% a...

  7. STUDY REGARDING SOME PHYSICAL - CHEMICAL CHARACTERISTICS OF THE YOGHURT WITH RED BEETROOT JUICE

    Directory of Open Access Journals (Sweden)

    Natalia Prodaniuc

    2009-12-01

    Full Text Available The study presents some physical - chemical characteristics of the beetroot juice yoghurt. The following determinations were carried out: the determination of the acidity by titration with sodium hydroxide ( NaOH N/10, the determination of the fat content by the acid-butirometric method and the determination of the dry substance using the drying oven with a 102 °C temperature.

  8. Evaluation of beetroot (Beta vulgaris L.) leaves during its developmental stages: a chemical composition study

    OpenAIRE

    Polyana Batoqui França Biondo; Joana Schuelter Boeing; Érica Oliveira Barizão; Nilson Evelazio de Souza; Makoto Matsushita; Claudio Celestino de Oliveira; Marcela Boroski; Jesuí Vergílio Visentainer

    2014-01-01

    Beetroot leaves (Beta vulgaris L.) are commonly cut off and discarded before using its bulb due to lack of knowledge of how to use them. Aiming at using these leaves, in the present study, in natura and dehydrated beetroot leaves were chemically characterized in terms of fatty acid composition, proximate composition, minerals, total phenolic compounds (TPC), and antioxidant activity by DPPH• in different stages (60, 80, and 100 days) of development. The beetroot leaves showed significant leve...

  9. Quality assessment of mized fruit squash: physico-chemical analysis, senory evaluation and storage studies

    OpenAIRE

    Jothi, J.S.; Karmoker, P.; Sarower, K.

    2014-01-01

    Fruits and vegetables belong to an essential class of foods that supply human diet with nutritive requirements including vitamins and minerals which are essential for normal body health and function. The study was carried out to determine the physico-chemical analysis and sensory qualities of mixed fruit squash. Carrot (Drocus carota), papaya (Carica papaya) and banana (Musa sapientum) juice were standardized to produce mixed squash which was stored for 9 weeks in sterilized glass bottles at ...

  10. Comparative study of trichloroacetic acid versus glycolic acid chemical peels in the treatment of melasma

    OpenAIRE

    Kumari Rashmi; Thappa Devinder

    2010-01-01

    Background: Melasma is a common cause of facial hyperpigmentation with significant cosmetic deformity. Many modalities of treatment are available, but none is satisfactory. Aim: This study was designed to compare the therapeutic response of melasma in Indian women to glycolic acid (GA 20-35%) versus trichloroacetic acid (TCA 10-20%) for chemical peeling. Methods: Forty nonpregnant female patients with a minimum melasma area and severity index (MASI) of 10 were recruited in the s...

  11. A detailed comparative study between chemical and bioactive properties of Ganoderma lucidum from different origins

    OpenAIRE

    Stojković, Dejan; Barros, Lillian; Ricardo C. Calhelha; Glamočlija, Jasmina; Ćirić, Ana; Van Griensven, Leo J. L. D.; Soković, Marina; Ferreira, Isabel C. F. R.

    2014-01-01

    A detailed comparative study on chemical and bioactive properties of wild and cultivated Ganoderma lucidum from Serbia (GS) and China (GCN) was performed. This species was chosen because of their worldwide use as medicinal mushroom. Higher amounts of sugars were found in GS, while higher amounts of organic acids were recorded in GCN. Unsaturated fatty acids predominated over saturated fatty acids. GCN revealed higher antioxidant activity, while GS exhibited inhibitory potential...

  12. Recent XAS studies into Homogeneous metal catalyst in fine chemical and pharmaceutical syntheses

    OpenAIRE

    Sherborne, GJ; Nguyen, BN

    2015-01-01

    A brief review of studies using X-ray Absorption Spectroscopy (XAS) to investigate homogeneous catalytic reactions in fine chemical and pharmaceutical context since 2010 is presented. The advantages of the techniques over traditional lab-based analytical tools, particularly when NMR spectroscopy fails to deliver mechanistic insights, are summarised using these examples. A discussion on the current limitations of the techniques and challenges in the near future is also included. Graphical abst...

  13. Studies on Physico-Chemical Properties of Rice Bran Wax and its Comparison with Carnauba Wax

    OpenAIRE

    Avish D. Maru; Rajendra K. Surawase; Prashant V. Bodhe

    2012-01-01

    Rice bran wax is a natural vegetable wax and is a value added by product of Rice bran oil refineries. It is hard nontacky wax and contains higher fatty alcohols and esters which make it comparable to Carnauba wax. In the present work, studies are carried out on Rice bran wax for various physico-chemical properties like solubility, melting point, specific gravity, moisture content, saponification value, acid value, ester value, hydroxyl value, unsaponifiable matter, Iodine number etc. The obse...

  14. Study of Physico-Chemical Characteristics of Wastewater in an Urban Agglomeration in Romania

    OpenAIRE

    Paula Popa; Mihaela Timofti; Mirela Voiculescu; Silvia Dragan; Catalin Trif; Georgescu, Lucian P.

    2012-01-01

    This study investigates the level of wastewater pollution by analyzing its chemical characteristics at five wastewater collectors. Samples are collected before they discharge into the Danube during a monitoring campaign of two weeks. Organic and inorganic compounds, heavy metals, and biogenic compounds have been analyzed using potentiometric and spectrophotometric methods. Experimental results show that the quality of wastewater varies from site to site and it greatly depends on the origin of...

  15. Study of postharvest changes in the chemical composition of persimmon by HPLC

    OpenAIRE

    BALTACIOĞLU, Hande; Nevzat ARTIK

    2013-01-01

    Chemical composition, total phenolic content, phenolic compounds, sugars, and L-ascorbic acid content of persimmon fruits of 6 different persimmon cultivars obtained from Ordu, Turkey, were evaluated in this study. Four astringent persimmon cultivars (Türkay, Hachiya, 07 TH 13, and Moralı) and 2 nonastringent persimmon cultivars (Tozlayıcı and Fuyu) were used for analysis. In order to determine total phenolic content in persimmon fruits, the Folin-Ciocalteu colorimetric method was used. High-...

  16. Experimental study of chaos synchronization in the Belousov-Zhabotinsky chemical system

    International Nuclear Information System (INIS)

    Employing self-adaptive parameter regulation scheme, chaos synchronization in the Belousov-Zhabotinsky-CSTR chemical system has been studied experimentally. By optimizing the combination of regulation parameters, the trend of chaos synchronization is observed and the prediction of chaos synchronization from numerical simulation is thus verified by the experiment. In addition, the difference of sensitivity to noise with the mass coupling scheme and the self-adaptive parameter regulation scheme in chaos synchronization has also been discussed

  17. PRELIMINARY STUDY ON ENHANCED PROPERTIES AND BIOLOGICAL RESISTANCE OF CHEMICALLY MODIFIED ACACIA SPP.

    OpenAIRE

    H. P. S. Abdul Khalil; Irshad ul Haq Bhat,; Khairul B. Awang

    2010-01-01

    A preliminary experimental study was carried out to examine the ability of a chemically modified Acacia spp. to resist biodegradation. The modifications of Acacia mangium and Acacia hybrid were carried out by propionic anhydride and succinic anhydride in the presence of sodium formate as a catalyst. The treated samples were found resistant to microbial attack, while the untreated ones were damaged on 12 months exposure to a soil burial. The appearance grading, mass loss, mechanical properties...

  18. Chemical properties of the transactinide elements studied in liquid phase with SISAK

    OpenAIRE

    Omtvedt, J.P.; Alstad, J.; Bjornstad, T.; Dullmann, Ch.E.; Gregorich, K.E.; Hoffman, D C; Nitsche, H.; Opel, K.; Polakova, D.; Samadani, F.; Schulz, F.; Skarnemark, G.; Stavsetra, L.; Sudowe, R.; Zheng, L.

    2008-01-01

    This article starts with a review of the current SISAK liquid-liquid extraction system, as used after the physical preseparator BGS at LBNL for chemical studies of transactinide elements. Emphasis will be on new additions and developments. Then the possibilities offered by the new TASCA separator at GSI and the use of actinide targets at both GSI and LBNL are discussed with respect to future SISAK transactinide experiments. Finally, current and future liquid-liquid extraction systems for...

  19. Application of isotopic and chemical methods to the study of hydrological problems in Brazilian northeastern areas

    International Nuclear Information System (INIS)

    Hydrological studies are reported with samples of ground water from several region of northern - and northeastern Brazil: Marajo Island (State of Para), State of Piaui, Ceara and Rio Grande do Norte. A description is given of the utilization of chemical and isotopic methods, in particular measurements of tritium concentration and 14C- counting techniques for the determination of the origin and residence time of water. (I.C.R.)

  20. Study of Chemical Constituents and Medicinal Uses of Indicator Species of District Bannu

    OpenAIRE

    Rehman ullah khan; Saad Ullah khan; Sultan Mehmood; Ihsan ullah; Aziz Khan

    2013-01-01

    The present study was carried out to assess record and report the chemical constituents and ethnobotanical knowledge of indicator species of District Bannu. Medicinal outlines of about 57 plants were recorded through interview local people i.e. farmers, herbalists, hakims and Medicinal plants user dealers. The present investigation comprises the indigenous uses of 57 species belonging to 36 families of Angiosperms based upon their utility. Out of this rich Medicinal germplasm, 66.15% plants a...