WorldWideScience
1

Molecular-Level Processes Governing the Interaction of Contaminants with Iron and Manganese Oxides - Final Report  

Energy Technology Data Exchange (ETDEWEB)

Many of the inorganic and organic contaminants present in sediments at DOE sites can be altered or destroyed by reduction and oxidation (redox) reactions occurring at mineral surfaces. A fundamental understanding of such redox processes provided by molecular-level studies on structurally and compositionally well-defined mineral surfaces will lead to: (i) improved models of contaminant fate and transport in geochemical systems, and (ii) optimized manipulation of these processes for remediation purposes. To contribute to this understanding, we will study, both experimentally and theoretically, redox processes involving three important contaminants - chromate ion, carbon tetrachloride, and trichloroethene TCE, on the following iron and manganese oxides - hematite, magnetite, maghemite, and pyrolusite. These oxides and their hydroxylated analogs commonly occur as coatings on minerals or as interfaces in the subsurface environment. Single-crystal surfaces of these oxides will be synthesized in carefully controlled fashion by molecular beam epitaxy. These surfaces, as well as high surface are powdered samples of these oxides, will be used in spectroscopic and kinetic experiments in both aqueous and gas phases. Our goal is to identify products and to determine the kinetics and mechanisms of surface-catalyzed redox reaction of Cr(VI) and CR(III), and the reductive dechlorination of carbon tetrachloride and TCE. The combination of theory and experiment will provide the base information needed to scale from the molecular level to the microscopic grain level minerals.

Brown Jr., G. E.; Chambers, S. A.

1999-10-31

2

Molecular-Level Processes Governing the Interaction of Contaminants with Iron and Manganese Oxides - Final Report; FINAL  

International Nuclear Information System (INIS)

Many of the inorganic and organic contaminants present in sediments at DOE sites can be altered or destroyed by reduction and oxidation (redox) reactions occurring at mineral surfaces. A fundamental understanding of such redox processes provided by molecular-level studies on structurally and compositionally well-defined mineral surfaces will lead to: (i) improved models of contaminant fate and transport in geochemical systems, and (ii) optimized manipulation of these processes for remediation purposes. To contribute to this understanding, we will study, both experimentally and theoretically, redox processes involving three important contaminants - chromate ion, carbon tetrachloride, and trichloroethene TCE, on the following iron and manganese oxides - hematite, magnetite, maghemite, and pyrolusite. These oxides and their hydroxylated analogs commonly occur as coatings on minerals or as interfaces in the subsurface environment. Single-crystal surfaces of these oxides will be synthesized in carefully controlled fashion by molecular beam epitaxy. These surfaces, as well as high surface are powdered samples of these oxides, will be used in spectroscopic and kinetic experiments in both aqueous and gas phases. Our goal is to identify products and to determine the kinetics and mechanisms of surface-catalyzed redox reaction of Cr(VI) and CR(III), and the reductive dechlorination of carbon tetrachloride and TCE. The combination of theory and experiment will provide the base inry and experiment will provide the base information needed to scale from the molecular level to the microscopic grain level minerals

3

Insights into surface–adsorbate interactions in corrosion inhibition processes at the molecular level  

International Nuclear Information System (INIS)

Graphical abstract: The interaction of 2-((3-methylpyridine-2-imino)methyl)phenol (MPIMP) with the Fe(1 1 0) surface was clarified at the molecular level using density functional theory (DFT). Highlights: •2-((3-Methylpyridine-2-imino)methyl)phenol was tested as a corrosion inhibitor. •Its interaction with the surface was characterized using density functional theory. •Three stable adsorption configurations on Fe(1 1 0) surface were identified. -- Abstract: 2-((3-Methylpyridine-2-imino)methyl)phenol (MPIMP) was investigated as a potential corrosion inhibitor for mild steel in 0.5 M HCl solution using impedance spectroscopy (IS). Changes in impedance parameters indicated that adsorption of MPIMP occurred on the mild steel surface. Three stable adsorption configurations for MPIMP on the Fe(1 1 0) surface were identified as a result of geometry optimization starting from several adsorption geometries using density functional theory (DFT). Involvement of the delocalized ?-electrons of the aromatic rings in the interaction provides extra stabilization to the flat adsorption configurations

4

Excited states structure and processes: Understanding organic light-emitting diodes at the molecular level  

International Nuclear Information System (INIS)

Photo- or electro-excited states in polyatomic molecules, aggregates, and conjugated polymers are at the center of organic light-emitting diodes (OLEDs). These can decay radiatively or non-radiatively, determining the luminescence quantum efficiency of molecular materials. According to Kasha’s rule, light-emission is dictated by the lowest-lying excited state. For conjugated polymers, the electron correlation effect can lead the lowest-lying excited state to the even-parity 2Ag state which is non-emissive. To understand the nature of the low-lying excited state structure, we developed the density matrix renormalization group (DMRG) theory and its symmetrization scheme for quantum chemistry applied to calculate the excited states structure. We found there are three types of 1Bu/2Ag crossover behaviors: with electron correlation strength U, with bond length alternation, and with conjugation length. These directly influence the light-emitting property. For the electro-excitation, carriers (electron and hole) are injected independently, forming both singlet and triplet excited bound states with statistically 25% and 75% portions, respectively. We found that the exciton formation rate can depend on spin manifold, and for conjugated polymers, the singlet exciton can have larger formation rate leading to the internal electroluminescence quantum efficiency larger than the 25% spin statistical limit. It is originated from the interchain electron correlation as well as intrachain lattice relaxation. For the dipole allowed emissive state, the radiative decay process via either spontaneous emission or stimulated emission can be computed from electronic structure plus vibronic couplings. The challenging issue lies in the non-radiative decay via non-adiabatic coupling and/or spin–orbit coupling. We developed a unified correlation function formalism for the excited state radiative and non-radiative decay rates. We emphasized the low-frequency mode mixing (Duschinsky rotation) effect on the non-radiative decay. We further combined the non-adiabatic coupling and spin–orbit coupling for the triplet state decay (phosphorescence) quantum efficiency. All the formalisms have been developed analytically, which have been applied to optical spectroscopy, aggregation-induced emission phenomena, and polymer photovoltaic property

5

Supercritical fluid processing of polymer thin films: an X-ray study of molecular-level porosity.  

Science.gov (United States)

This paper reviews our recent experimental results that address the effects of solvent density inhomogeneities in supercritical carbon dioxide (scCO(2)) on polymer thin film processing. The key phenomenon is excess sorption of CO(2) molecules into polymer thin films even when the bulk miscibility with CO(2) is very poor. We have found that the amount of the excess sorption is attributed to the large density fluctuations in scCO(2) near the critical point. Further, taking advantage of the vitrification process of polymer chains through quick evaporation of CO(2), we can preserve the "expanded" structures as they are. The resultant films have large degree of molecular-level porosity that is very useful in producing coatings with low dielectric constants, enhanced adhesion, and metallization properties. These characteristics can be achieved in an environmentally "green" manner, without organic solvents, and are not specific to any class of polymers. PMID:17239334

Koga, Tadanori; Jerome, J; Rafailovich, M H; Chu, B; Douglas, J; Satija, S

2006-12-21

6

Supercritical Fluid Processing of Polymer Thin Films: An X-ray Study of Molecular-Level Porosity  

International Nuclear Information System (INIS)

This paper reviews our recent experimental results that address the effects of solvent density inhomogeneities in supercritical carbon dioxide (scCO2) on polymer thin film processing. The key phenomenon is excess sorption of CO2 molecules into polymer thin films even when the bulk miscibility with CO2 is very poor. We have found that the amount of the excess sorption is attributed to the large density fluctuations in scCO2 near the critical point. Further, taking advantage of the vitrification process of polymer chains through quick evaporation of CO2, we can preserve the 'expanded' structures as they are. The resultant films have large degree of molecular-level porosity that is very useful in producing coatings with low dielectric constants, enhanced adhesion, and metallization properties. These characteristics can be achieved in an environmentally 'green' manner, without organic solvents, and are not specific to any class of polymers

7

Systems- and Molecular-Level Elucidation of Signaling Processes Through Chemistry  

Science.gov (United States)

Complete understanding of the molecular mechanisms of signal transduction is a major focus of research in the postgenomic era. Efforts to realize this goal have benefited from interdisciplinary approaches, specifically through the development of new technologies. Several groups have now described new chemical strategies to probe signaling with broadly different degrees of focus. The first report employs an enzymatic tagging strategy to monitor global proteolytic cleavage events that occur during apoptosis. The second study illustrates a general method to functionally characterize a specific kinase through the identification of its substrates. Finally, the third report describes a synthetic route to generate ubiquitinated proteins and demonstrates the utility of protein chemistry in understanding the detailed biochemical mechanisms of signaling. Together, these papers highlight the power of chemical tools to examine specific networks, thereby expanding our understanding of signaling pathways.

Kyle P. Chiang (The Rockefeller University; Laboratory of Synthetic Protein Chemistry REV)

2008-10-21

8

Identification of light absorbing oligomers from glyoxal and methylglyoxal aqueous processing: a comparative study at the molecular level  

Science.gov (United States)

Numerous studies point to the reactive uptake of gaseous low molecular weight carbonyls onto atmospheric waters (clouds/fog droplets and wet aerosols) as an important SOA formation route not yet included in current models. However, the evaluation of these processes is challenging because water provides a medium for a complex array of reactions to take place such as self-oligomerization, aldol condensation and Maillard-type browning reactions in the presence of ammonium salts. In addition to adding to SOA mass, aqueous chemistry products have been shown to include light absorbing, surface-active and high molecular weight oligomeric species, and can therefore affect climatically relevant aerosol properties such as light absorption and hygroscopicity. Glyoxal (GLY) and methylglyoxal (MGLY) are the gaseous carbonyls that have perhaps received the most attention to date owing to their ubiquity, abundance and reactivity in water, with the majority of studies focussing on bulk physical properties. However, very little is known at the molecular level, in particular for MGLY, and the relative potential of these species as aqueous SOA precursors in ambient air is still unclear. We have conducted experiments with both laboratory solutions and chamber-generated particles to simulate the aqueous processing of GLY and MGLY with ammonium sulphate (AS) under typical atmospheric conditions and investigated their respective aging products. Both high performance liquid chromatography coupled with UV-Vis detection and ion trap mass spectrometry (HPLC-DAD-MSn) and high resolution mass spectrometry (FTICRMS) have been used for molecular identification purposes. Comprehensive gas chromatography with nitrogen chemiluminescence detection (GCxGC-NCD) has been applied for the first time to these systems, revealing a surprisingly high number of nitrogen-containing organics (ONs), with a large extent of polarities. GCxGC-NCD proved to be a valuable tool to determine overall amount and rates of formation of the light absorbing species. Data obtained from laboratory solutions were merged with those from SOA generated in chamber experiments conducted at the European PhotoReactor (EUPHORE) from the uptake of gas-phase GLY and MGLY onto AS seeds. While in general the results confirm previous studies in ranking MGLY as more effective than GLY in brown carbon formation, the link between overall optical properties and the identified molecular species is reported here for the first time for both systems.

Finessi, Emanuela; Hamilton, Jacqueline; Rickard, Andrew; Baeza-Romero, Maria; Healy, Robert; Peppe, Salvatore; Adams, Tom; Daniels, Mark; Ball, Stephen; Goodall, Iain; Monks, Paul; Borras, Esther; Munoz, Amalia

2014-05-01

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Supercritical Fluid Processing of Polymer Thin Films: An X-ray Study of Molecular-Level Porosity  

Energy Technology Data Exchange (ETDEWEB)

This paper reviews our recent experimental results that address the effects of solvent density inhomogeneities in supercritical carbon dioxide (scCO{sub 2}) on polymer thin film processing. The key phenomenon is excess sorption of CO{sub 2} molecules into polymer thin films even when the bulk miscibility with CO{sub 2} is very poor. We have found that the amount of the excess sorption is attributed to the large density fluctuations in scCO{sub 2} near the critical point. Further, taking advantage of the vitrification process of polymer chains through quick evaporation of CO{sub 2}, we can preserve the 'expanded' structures as they are. The resultant films have large degree of molecular-level porosity that is very useful in producing coatings with low dielectric constants, enhanced adhesion, and metallization properties. These characteristics can be achieved in an environmentally 'green' manner, without organic solvents, and are not specific to any class of polymers.

Koga,T.; Rafailovich, M.; Chu, B.; Douglas, J.; Satija, S.

2006-01-01

10

Theoretical studies of molecular processes  

Science.gov (United States)

The current thesis concerns with theoretical studies of molecular processes and consists of two parts. The first part includes theoretical studies of dynamics of unimolecular and bimolecular reactions, in particular those involving non-adiabatic processes. In chapter 2 and 3, we have presented our studies of detailed mechanisms for the photodissociation of C2H2 and C2H, and the ion-molecule reactions of C2H2+ + CH4 or NH3, respectively. In chapter 4, we have presented our study that extends TST to non-adiabatic reactions, and an application of the theory of the spin-forbidden reaction of CH(2/Pi)+N2. In chapter 5, we have included our analyses on the photodissociation of triplet ketene, where an extensive seam has been found all along the reaction coordinate. Finally, in Chapter 6, we have presented our study on the photodissociation of O3/sp-, which includes qualitative electronic structure calculations and construction of global potential energy functions for coupled electronic states. The second part of the thesis deals with theoretical studies of organometallic reactions, metal clusters, and gas-surface interactions. With theoretical calculations, one can study the reactivities of transition metal compounds systematically, which allows one to understand the key parameters that control the reactivities of those compounds. In chapter 2, we have presented our implementation of analytical hessian for effective core potential, which makes normal mode analysis possible for large organometallic systems and has proven to be very useful in the study of systems containing transition metals. In chapter 3-5, we have included our studies on the detailed mechanisms of several interesting reactions including platinum/palladium(0) catalyzed diboration and thioboration reactions of acetylene and olefin, and H- H/C-H bond activation on small metal clusters Pt/Pdn(n = 1[-]3). For truly large systems such as surfaces or proteins, full quantum mechanical treatments are computationally too demanding, and methods that combine molecular orbital (MO) theories and molecular mechanics (MM), or higher level and lower level of MO theories (IMOMO) become favorable. In chapter 6, we have presented our DFT and IMOMO study on the iodine etching of the Si(100) reconstructed surface, where we have demonstrated that IMOMO method was indeed able to provide accurate description of large systems.

Cui, Qiang

1997-09-01

11

Atomic and molecular collision processes  

International Nuclear Information System (INIS)

530Accomplishments during the course of a 44-month program of code development and high precision calculations for electron collisions with atoms, atomic ions, and molecules are summarized. In electron-atom and -ion collisions, we were primarily concerned with the fundamental physics of the process that controls excitation in high temperature plasmas. In the molecular work, we pursued the development of techniques for accurate calculations of ro-vibrational excitation of polyatomic molecules, to the modeling of gas-phase laser systems. Highlights from the seven technical paper published as a result of this contract include: The resolution of a long history of unexplained anomalies and experimental/theoretical discrepancies by a demonstration that the Coulomb phase must be included in scattering amplitudes for electron-ion collisions. Definitive close-coupling calculations of cross sections for electron impact excitation of Be+, using a very elaborate expansion for the collision system and inclusion of both one- and two-body terms for the effect of core polarization. Detailed state-of-the-art calculations for electron-impact excitation of the sodium-like ion A ell 2+ that included core-polarization interactions, and which also produced new data on bound-state energy levels for the magnesium-like ion A ell + and oscillator strengths for A ell 2+. Partial cross sections for excitation of the 3p level of sodium at energies just above threshold calculated using a four-state close-coupling approach, including both total cross sections and those for excitation as a function of the change in the spin and orbital angular momentum projection quantum numbers of the target electron. Generalization of our electron-molecule scattering code to carry out full vibrational close-coupling calculations with an exact treatment of exchange and with a parameter-free representation of correlation and polarization interactions, and application to HF and H2

12

CONTROL STRATEGIES FOR LEVEL PROCESSES  

OpenAIRE

Processes with large time constants, like the level process, represent a large number of applications in industry. These systems must be treated in both steady and dynamic state and effective control solutions should be proposed. In a PI controller working under saturation, problems like windup appear. This paper presents a classical PI-controlled feedback loop, which is part of an industrial level control system. Based on the existing PI controller, antiwindup and feedback compensation schem...

Mircea Dulau; Stelian-Emilian Oltean; Adrian-Vasile Duka

2012-01-01

13

Theory of atomic and molecular collision processes  

International Nuclear Information System (INIS)

This research is primarily involved with the development of theoretical methods and models for describing atomic and molecular collision processes. Current projects include quantum mechanical reaction scattering and reaction dynamics in polyatomic molecular systems

14

Temperature- and pressure-dependent densities, self-diffusion coefficients, and phase behavior of monoacid saturated triacylglycerides: toward molecular-level insights into processing.  

Science.gov (United States)

Using molecular-dynamics (MD) simulations the densities and self-diffusion coefficients of a range of liquid monoacid triacylglycerides (TAGs) have been studied as a function of temperature and, for the first time, pressure. While offset by their ambient properties, the response of the TAGs to temperature and pressure is qualitatively similar. Application of pressure was found to significantly increase densities and reduce diffusion of the TAG molecules, suggesting that it may have as much a role in processing and crystallizing TAGs as supercooling does. A solution of glycerol tripalmitate and glycerol trihexanoate was also studied, showing that application of pressure should lead to a significant decrease in the saturation point of the solution, which is an important consideration for processing TAGs. Different solid/liquid interfaces of glycerol tripalmitate have also been investigated. Although crystal growth could not be observed, dissolution of one interface was seen in the MD simulations. The results suggest that over moderate distances the melting of TAGs may be cooperative in nature, rather than involving dissolution of individual TAG molecules. PMID:22500590

Greiner, Maximilian; Reilly, Anthony M; Briesen, Heiko

2012-05-23

15

The Accuracy of Molecular Processes  

Science.gov (United States)

Recombination is arguably one of the most fundamental mechanisms driving genetic diversity during evolution. Recombination takes place in one way or another from viruses such as HIV and polio, to bacteria, and finally to man. In both prokaryotes and eukaryotes, homologous recombination is assisted by enzymes, recombinases, that promote the exchange of strands between two segments of DNA, thereby creating new genetic combinations. In bacteria, homologous recombination takes place as a pathway for the repair of DNA lesions and also during horizontal or lateral gene transfer processes, in which cells take in exogenous pieces of DNA. This allows bacteria to evolve rapidly by acquiring large sequences of DNA, a process which would take too long by gene duplications and single mutations. I will survey recent results on the fidelity of homologous recombination as catalyzed by the bacterial recombinase RecA. These results show discrimination up to the level of single base mismatches, during the initial stages of the recombination process. A cascaded kinetic proofreading process is proposed to explain this high discrimination. Kinetic proofreading ideas are also reviewed.

Stavans, Joel

16

Dynamical processes in atomic and molecular physics  

CERN Document Server

Atomic and molecular physics underlie a basis for our knowledge of fundamental processes in nature and technology and in such applications as solid state physics, chemistry and biology. In recent years, atomic and molecular physics has undergone a revolutionary change due to great achievements in computing and experimental techniques. As a result, it has become possible to obtain information both on atomic and molecular characteristics and on dynamics of atomic and molecular processes. This e-book highlights the present state of investigations in the field of atomic and molecular physics. Rece

Ogurtsov, Gennadi

2012-01-01

17

Probing Radiation Damage at the Molecular Level  

International Nuclear Information System (INIS)

Radiation damage of DNA and other cellular components has traditionally been attributed to ionisation via direct impact of high-energy quanta or by complex radical chemistry. However recent research has shown that strand breaks in DNA may be initiated by secondary electrons and is strongly dependent upon the target DNA base identity. Such research provides the fascinating perspective that it is possible that radiation damage may be described and understood at an individual molecular level introducing new possibilites for therapy and perhaps providing an insight into the origins of life

18

Designing an university-level module on molecular imaging chemistry  

International Nuclear Information System (INIS)

Full text: Why do we need radiopharmacy, radiopharmacy, radiopharmacy training? In this post-genomic era, molecular imaging has gain tremendous interest not only amongst physicians but also from biologists, chemists, physicists, engineers, statisticians, pharmaceutical companies and even from governments. There is no doubt that nuclear medicine has been engaged in molecular medicine more than one decade ago. Positron emission tomography (PET) has reawaken interest in long forgotten radiopharmacy. Only major hospitals in the developed countries have invested in the development of dedicated radiopharmacy laboratory and training or recruitment of radiopharmacist. But PET has forced nuclear medicine to create a radiopharmacy unit and adopt radiopharmacy guidelines such as good radiopharmaceutical practice (GRPP) and good manufacturing practice (GMP). It is compounded by the fact that SPECT radiopharmaceutical chemistry has advanced significantly for both diagnostics and therapeutics, which calls for a high level of understanding on radiopharmaceutical chemistry and technical know-how. These factors eventually lead to introduction of tran ing program, courses and degree program. The most striking examples will be European Association of Nuclear Medicine (EANM) radiopharmacy courses and a series of IAEA activities on GRPP, GMP and technologist training programs. Various forms of training or education program can be formulated for various levels, starting from basic radiopharious levels, starting from basic radiopharmacy course to PhD program, depending on the following factors; (1) National interest and policies on bio/medical sector; (2) Size of the nuclear medicine community in the respective country; (3) Institution interest and policies; and (4) Existing infrastructure and programs. Current Radiopharmacy Education in Singapore: In Singapore, all of the major nuclear medicine centers are supervised by radiopharmacists with PhD degree. All of the nuclear medicine technologists in the major centers have got training in radiopharmacy both in theory and hands-on practice. Final-year radiology students in Polytechnic have to go through a series of lectures on radiopharmacy and also practicals in hospital radiopharmacy laboratory. But due to the Government's initiatives on biomedical industries and also due to a global trend, interest in bio/medical imaging is rising among scientists and students. There is a need to fulfil this demand by introducing new course or modules at the University level. Designing an university-level module on molecular imaging chemistry: In National University of Singapore, a graduate student (MSc and PhD) level 5 module on ''Medical Imaging'' has already been introduced and a new module on ''Molecular Imaging Chemistry'' will be introduced soon. A module of this kind should serve as a link between chemistry, molecular imaging and clinical application with emphasis on chemical probe design. And should introduce contemporary topics and emerging concepts in chemistry related to molecular imaging. A brief introduction on different modalities of molecular imaging and principles of biomedical imaging should be introduced including principles of medical imaging equipment. How this knowledge will direct the chemical synthesis should be highlighted (lead directed synthesis). There should be a coverage on pharmacology and drug discovery process as imaging probes could be considered as drugs. Here is an example of an outline for such module: - Introduction: - What is molecular imaging? - Why molecular imaging? - What is biomedical imaging? - Different modalities of molecular imaging; - Different types of molecular imaging; - In vitro, ex vivo, in vivo imaging; Drug discovery process; - Pharmacological basis. Molecular Imaging Chemistry: - general construct of imaging probe (molecular reporter system); - Bioimaging factors influencing chemical probe synthesis; Optical imaging probes; - Radioimaging probes; - MR contrast agents; - Probes for other modalities, X ray, ultrasound, etc. Examples of practical application

19

Atomic and molecular processes in fusion plasmas  

Energy Technology Data Exchange (ETDEWEB)

The role of atomic and molecular processes in achieving and maintaining the conditions for thermonuclear burn in a magnetically confined fusion plasma is described. Emphasis is given to the energy balance and power and particle exhaust issues. The most important atomic and molecular processes which affect the radiation losses and impurity transport in the core plasma, the neutral particle transport in the plasma edge and the radiative cooling of divertor plasmas are discussed in greater detail. (author)

Janev, R.K. [International Atomic Energy Agency, Vienna (Austria)

1997-01-01

20

Levels of Processing in Mild Disabilities.  

Science.gov (United States)

This study examined the effects of the second level (intermediate acoustical processing of rhyming words) and the third level (deep-semantic processing of words in sentences) of the "levels of processing" framework on memory performance of four types of intermediate-grade students (52 "normal" students, 50 students with learning disabilities, 25…

Al-Hilawani, Yasser A.; And Others

21

1985 bibliography of atomic and molecular processes  

Energy Technology Data Exchange (ETDEWEB)

This annotated bibliography includes papers on atomic and molecular processes published during 1985. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory.

Barnett, C.F.; Gilbody, H.B.; Gregory, D.C.; Griffin, P.M.; Havener, C.C.; Howald, A.M.; Kirkpatrick, M.I.; McDaniel, E.W.; Meyer, F.W.; Morgan, T.J. (comps.)

1986-06-01

22

1982 bibliography of atomic and molecular processes  

International Nuclear Information System (INIS)

This annotated bibliography includes papers on atomic and molecular processes published during 1982. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory

23

1982 bibliography of atomic and molecular processes  

Energy Technology Data Exchange (ETDEWEB)

This annotated bibliography includes papers on atomic and molecular processes published during 1982. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory.

Barnett, C.F.; Crandall, D.H.; Gilbody, H.B.; Gregory, D.C.; Kirkpatrick, M.I.; McDaniel, E.W.; McKnight, R.H.; Meyer, F.W.; Morgan, T.J.; Phaneuf, R.A. (comps.)

1984-05-01

24

1980 bibliography of atomic and molecular processes  

International Nuclear Information System (INIS)

This annotated bibliography lists 2866 works on atomic and molecular processes reported in publications dated 1980. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory, to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing are indexes of reactants and authors

25

1978 bibliography of atomic and molecular processes  

International Nuclear Information System (INIS)

This annotated bibliography lists 2557 works on atomic and molecular processes reported in publications dated 1978. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing are indexes of reactants and authors

26

1979 bibliography of atomic and molecular processes  

International Nuclear Information System (INIS)

This annotated bibliography lists 2146 works on atomic and molecular processes reported in publications dated 1979. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory, to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing are indexes of reactants and authors

27

1984 Bibliography of atomic and molecular processes  

International Nuclear Information System (INIS)

This annotated bibliography includes papers on atomic and molecular processes published during 1984. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory

28

1984 Bibliography of atomic and molecular processes  

Energy Technology Data Exchange (ETDEWEB)

This annotated bibliography includes papers on atomic and molecular processes published during 1984. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory.

Barnett, C.F.; Gilbody, H.B.; Gregory, D.C.; Griffin, P.M.; Havener, C.C.; Howard, A.M.; Kirkpatrick, M.I.; McDaniel, E.W.; Meyer, F.W.; Morgan, T.J. (comps.)

1985-04-01

29

Bibliography of atomic and molecular processes, 1983  

Energy Technology Data Exchange (ETDEWEB)

This annotated bibliography includes papers on atomic and molecular processes published during 1983. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory.

Barnett, C.F.; Crandall, D.H.; Gilbody, H.B.; Gregory, D.C.; Kirkpatrick, M.I.; McDaniel, E.W.; McKnight, R.H.; Meyer, F.W.; Morgan, T.J.; Phaneuf, R.A. (comps.)

1984-10-01

30

Experimental determination of enthalpies of solution of tetraphenyl porphyrin (TPP) and some metal derivatives, in chloroform: interpretation of the solvation processes at a molecular level.  

Science.gov (United States)

The enthalpies of solution, Delta(sol)H(m), for 5,10,15,20-tetraphenylporphine (CA registry number 917-23-7, TPP), 5,10,15,20-tetraphenylporphine of Co(II), Ni(II), Cu(II), and Zn(II) (to be written as CoTPP, NiTPP, CuTPP, and ZnTPP) in chloroform, were calorimetrically measured at T = 298 K in the concentration ranging from 3.5 x 10(-5) to 2.8 x 10(-4) mol.kg(-1). Through the linear extrapolation of the experimental data, corresponding values at infinite dilution were determined as: Delta(sol)H(m) (ZnTPP) = (55.5 +/- 0.2) kJ x mol(-1), Delta(sol)H(m) (CoTPP) = (36.9 +/- 0.2) kJ x mol(-1), Delta(sol)H(m) (TPP) = (25.7 +/- 0.6) kJ x mol(-1), Delta(sol)H(m) (NiTPP) = (15.6 +/- 0.1) kJ x mol(-1), and Delta(sol)H(m) (CuTPP) = (15.6 +/- 0.1) kJ x mol(-1). The enthalpies of solvation for the five compounds were also determined using the previously published values for the enthalpy of sublimation, as well as complementary data from the literature. The values obtained are as follows: Delta(solv)H(m)(TPP) = -(158.3 +/- 2.1) kJ x mol(-1), Delta(solv)H(m)(CoTPP) = -(154.1 +/- 2.0) kJ x mol(-1), Delta(solv)H(m)(CuTPP) = -(149.4 +/- 5.0) kJ x mol(-1) Delta(solv)H(m)(NiTPP) = -(141.4 +/- 4.0) kJ x mol(-1), and Delta(solv)H(m)(ZnTPP) = -(140.5 +/- 3.0) kJ x mol(-1). The results are analyzed in relation to several molecular properties such as ionic radius, electronic spectra, and Connolly surface. An explanation of the observed trends for solvation enthalpies is proposed. PMID:20000579

Gamboa, Minerva; Campos, Myriam; Torres, Luis Alfonso

2010-01-18

31

Quantum mechanics of molecular rate processes  

CERN Document Server

This survey of applications of the theory of collisions and rate processes to molecular problems explores collisions of molecules with internal structure, generalized Ehrenfest theorem, theory of reactive collisions, and role of symmetry. It also reviews partitioning technique, equivalent potentials and quasibound states, theory of direct reactions, more. 1969 edition.

Levine, Raphael D

2011-01-01

32

Features, Events, and Processes: System Level  

International Nuclear Information System (INIS)

The primary purpose of this analysis is to evaluate System Level features, events, and processes (FEPs). The System Level FEPs typically are overarching in nature, rather than being focused on a particular process or subsystem. As a result, they are best dealt with at the system level rather than addressed within supporting process-level or subsystem level analyses and models reports. The System Level FEPs also tend to be directly addressed by regulations, guidance documents, or assumptions listed in the regulations; or are addressed in background information used in development of the regulations. This evaluation determines which of the System Level FEPs are excluded from modeling used to support the total system performance assessment for license application (TSPA-LA). The evaluation is based on the information presented in analysis reports, model reports, direct input, or corroborative documents that are cited in the individual FEP discussions in Section 6.2 of this analysis report

33

Process and apparatus for determining molecular spectra  

Energy Technology Data Exchange (ETDEWEB)

A process for determining molecular spectra in unseparated mixtures, in particular unseparated isotopic mixtures, which comprises allowing said mixture to successively flow through a photoreactor which is irradiated by an adjustable-wavelength laser and then through a mass spectrometer wherein the concentration of particles of specified mass is determined by variation of the wavelength of the laser or variation of the mass setting of the mass spectrometer in such a manner that a two-dimensional spectrum results having the parameters of wavelength and mass.

Boesl, U.; Neusser, H.J.; Schlag, E.W.

1984-02-21

34

Subjective visibility depends on level of processing.  

Science.gov (United States)

Is visual awareness graded or binary? Experimental work has provided support for both possibilities, leading to two coexisting but contradictory theoretical accounts. Here we propose a promising candidate factor through which to integrate both accounts: the depth of stimulus processing required by the task. We compared color identification (a low-level task) with numerical judgements (a high-level task) performed on the very same colored number stimuli. Psychophysical curves were analyzed for both objective discrimination performance and subjective visibility ratings on a trial-by trial basis. We observed a graded relationship between stimulus duration and visibility in the low-level task, but a more non-linear relationship in the high-level task. Both patterns of results have previously been consistently associated with the graded and the dichotomous account, respectively. Follow-up experiments that manipulate the level of processing can further unify previously inconsistent results, thus integrating two major theories of visual awareness. PMID:23978782

Windey, Bert; Gevers, Wim; Cleeremans, Axel

2013-11-01

35

Capillary leveling of stepped films with inhomogeneous molecular mobility  

OpenAIRE

A homogeneous thin polymer film with a stepped height profile levels due to the presence of Laplace pressure gradients. Here we report on studies of polymeric samples with precisely controlled, spatially inhomogeneous molecular weight distributions. The viscosity of a polymer melt strongly depends on the chain length distribution; thus, we learn about thin-film hydrodynamics with viscosity gradients. These gradients are achieved by stacking two films with different molecular...

Mcgraw, Joshua D.; Salez, Thomas; Ba?umchen, Oliver; Raphae?l, Elie; Dalnoki-veress, Kari

2013-01-01

36

Features, Events, and Processes: system Level  

International Nuclear Information System (INIS)

The purpose of this analysis report is to evaluate and document the inclusion or exclusion of the system-level features, events, and processes (FEPs) with respect to modeling used to support the total system performance assessment for the license application (TSPA-LA). A screening decision, either Included or Excluded, is given for each FEP along with the technical basis for screening decisions. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.113 (d, e, and f) (DIRS 156605). The system-level FEPs addressed in this report typically are overarching in nature, rather than being focused on a particular process or subsystem. As a result, they are best dealt with at the system level rather than addressed within supporting process-level or subsystem-level analyses and models reports. The system-level FEPs also tend to be directly addressed by regulations, guidance documents, or assumptions listed in the regulations; or are addressed in background information used in development of the regulations. For included FEPs, this analysis summarizes the implementation of the FEP in the TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from the TSPA-LA (i.e., why the FEP is excluded). The initial version of this report (Revision 00) was developed to support the total system performance assessment for site recommendation (TSPA-SR). This revision addresses the license application (LA) FEP List (DIRS 170760)

37

Features, Events, and Processes: system Level  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this analysis report is to evaluate and document the inclusion or exclusion of the system-level features, events, and processes (FEPs) with respect to modeling used to support the total system performance assessment for the license application (TSPA-LA). A screening decision, either Included or Excluded, is given for each FEP along with the technical basis for screening decisions. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.113 (d, e, and f) (DIRS 156605). The system-level FEPs addressed in this report typically are overarching in nature, rather than being focused on a particular process or subsystem. As a result, they are best dealt with at the system level rather than addressed within supporting process-level or subsystem-level analyses and models reports. The system-level FEPs also tend to be directly addressed by regulations, guidance documents, or assumptions listed in the regulations; or are addressed in background information used in development of the regulations. For included FEPs, this analysis summarizes the implementation of the FEP in the TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from the TSPA-LA (i.e., why the FEP is excluded). The initial version of this report (Revision 00) was developed to support the total system performance assessment for site recommendation (TSPA-SR). This revision addresses the license application (LA) FEP List (DIRS 170760).

D. McGregor

2004-10-15

38

Towards an Upper-Level Ontology for Molecular Biology  

OpenAIRE

There is a growing need for the general-purpose description of the basic ontological entities in the life sciences domain. Up until now, upper-level models are mainly purpose-driven, such as the GENIA ontology, originally devised as a vocabulary for corpus annotation. As an alternative, we here present BioTop, a description-logic-based top-level ontology for molecular biology, as an ontologically more conscious re-design of the GENIA ontology.

Schulz, Stefan; Beisswanger, Elena; Wermter, Joachim; Hahn, Udo

2006-01-01

39

Statistical kinetics of processive molecular motors  

Science.gov (United States)

We describe new theoretical and experimental tools for studying biological motor proteins at the single molecule scale. These tools enable measurements of molecular fuel economies, thereby providing insight into the pathways for conversion of biochemical energy into mechanical work. Kinesin is an ATP-dependent motor that moves processively along microtubules in discrete steps of 8 nm. How many molecules of ATP are hydrolysed per step? To determine this coupling ratio, we develop a fluctuation analysis, which relates the variance in records of mechanical displacement to the number of rate-limiting biochemical transitions in the engine cycle. Using fluctuation analysis and optical trapping interferometry, we determine that near zero load, single molecules of kinesin hydrolyse one ATP nucleotide per 8-nm step. To study kinesin behavior under load, we use a molecular force clamp, capable of maintaining constant loads on single kinesin motors moving processively. Analysis of records of motion under variable ATP concentrations and loads reveals that kinesin is a `tightly- coupled' motor, maintaining the 1:1 coupling ratio up to loads of ~ 5 pN. Moreover, a Michaelis-Menten analysis of velocity shows that the kinesin cycle contains at least two load- dependent transitions. The rate of one of these transitions affects ATP affinity, while the other does not. Therefore, the kinesin stall force must depend on the ATP concentration, as is demonstrated experimentally. These findings rule out existing theoretical models of kinesin motility. We develop a simple theoretical formalism describing a tightly-coupled mechanism for movement. This `energy-landscape' formalism quantitatively accounts for motile properties of RNA polymerase (RNAP), the enzyme that transcribes DNA into RNA. The shapes of RNAP force-velocity curves indicate that biochemical steps limiting transcription rates at low loads do not generate movement. Modeling suggests that high loads may halt RNAP by promoting a structural change which moves all or part of the enzyme backwards along the DNA through a distance of 5-10 base pairs. Using the energy landscape formalism, we also propose a model for kinesin. The model incorporates both the ATP-dependent and the ATP-independent mechanical transitions in the motor cycle and explains experimental measurements of kinesin velocity.

Schnitzer, Mark Jacob

1999-10-01

40

A Multi-step and Multi-level approach for Computer Aided Molecular Design  

DEFF Research Database (Denmark)

A general multi-step approach for setting up, solving and solution analysis of computer aided molecular design (CAMD) problems is presented. The approach differs from previous work within the field of CAMD since it also addresses the need for a computer aided problem formulation and result analysis. The problem formulation step incorporates a knowledge base for the identification and setup of the design criteria. Candidate compounds are identified using a multi-level generate and test CAMD solution algorithm capable of designing molecules having a high level of molecular detail. A post solution step using an Integrated Computer Aided System (ICAS) for result analysis and verification is included in the methodology. Keywords: CAMD, separation processes, knowledge base, molecular design, solvent selection, substitution, group contribution, property prediction, ICAS Introduction The use of Computer Aided Molecular Design (CAMD) for the identification of compounds having specific physic...

41

Actinides and environmental interfaces: striving for molecular-level understanding  

International Nuclear Information System (INIS)

Actinides can undergo a variety of complex chemical reactions in the environment. In addition to the formation of solid precipitates, colloids and dissolved solution species common to aqueous systems, actinide ions can interact with the surrounding geo and biomedia to change oxidation states or sorb on surfaces and colloids. The rate of migration is determined by aqueous solubility, and interactions with solid surfaces such as minerals, soils, natural organic matter, and soil microorganisms Sorption of aqueous actinide species on biological and geological matrices can be quantitatively described by a surface complexation or site-binding model. The disadvantage of this model is the difficulty in the experimental determination of the model parameters and surface reaction constants. Usually, a set of surface reactions and species are proposed based on knowledge of the solution speciation of the solute, and the reaction constants are usually derived by fitting computer-calculated absorption curves to experimental data. Because this process typically involves a large number of potentially adjustable parameters, it is likely to lead to non-unique parameter fitting and does not always result in a consistent set of parameters for the same systems. A fundamental molecular-level understanding of sorption processes of actinides on environmental surfaces is required to better understand and predict their transport behavior in nature. Several different surface spectroscopic techniral different surface spectroscopic techniques have been applied to the characterization of the adsorbed species and surface reactions and a direct determination of the sorbed species and surface reactions has become possible. The non-linear optical techniques of second harmonic and sum frequency generation (SHG and SFG) are ideally suited to study surfaces and interfaces of mineral oxides, biosurfactants and biopolymers, organic adlayers adsorbed on solid/mineral surfaces and soil organic matter, including humic and fulvic acids. Resonant enhanced second harmonic generation can probe the electronic (UV-vis region) structure of metal species adsorbed at a surface or interface. Infrared-visible sum frequency generation spectroscopy probes the infrared vibrational spectrum of molecules adsorbed at the interface. SHG/SFG studies will greatly assist with understanding reactivity at interfaces of oxides and soil organic matter with heavy metals and radionuclides/actinides. Time-resolved Laser-fluorescence spectroscopy (TRLFS) is a highly sensitive tool for actinides that absorb light and de-excite by fluorescence emission, e.g., U(VI) and Cm(III), to probe changes in actinide speciation and coordination environment in solution. This method can also be used to differentiate whether adsorbed species form surface complexes or surface precipitates. Recently, it was shown that the intense synchrotron radiation can change the oxidation states of redox-sensitive actinide samples which may cause erroneous results, and low temperature measurements are now used to alleviate this shortcoming. X-ray Absorption Fine Structure (XAFS) Spectroscopy is composed of two component spectroscopies, X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) which provide element specific oxidation state and local structure information, respectively. EXAFS (Extended X-ray Absorption Fine Structure Spectroscopy) provides information on the chemical environment of particular actinide, in particular bond lengths and the number of neighboring atoms. Combining both methods, detailed knowledge of the different processes resulting from the interaction of the selected actinides with environmental interfaces can be gained. XANES and EXAFS measurements and TRLFS studies to obtain molecular-level mechanistic details of actinide interaction with common environmental solutions and interfaces will be presented together with first SHG/SFG characterization results of model systems for environmental interfaces. Areas will be outlined where integrated interdisciplin

42

Nanoparticles of Copper Stimulate Angiogenesis at Systemic and Molecular Level  

Directory of Open Access Journals (Sweden)

Full Text Available Copper is a key element affecting blood vessel growth and muscle development. However, the ions released from Cu salts are toxic. Given their specific physicochemical properties, nanoparticles of Cu (NanoCu may have different bioactivity and affect the development of blood vessel and muscles in a different manner than Cu salts. The objective of the study was to evaluate the influence of NanoCu on embryo development and angiogenesis at the systemic and molecular level, in experiments using a chick embryo model. Fertilized chicken eggs were divided into a control group, and groups injected with a placebo, CuSO4 or NanoCu. Embryo development at the whole body level and molecular indices using an embryo chorioallantoic membrane model were measured during embryogenesis. The present study indicated for the first time that NanoCu have pro-angiogenic properties at the systemic level, to a greater degree than CuSO4 salt. The properties of NanoCu were confirmed at the molecular level, demonstrating significant effects on mRNA concentration and on mRNA gene expression of all pro-angiogenic and pro-proliferative genes measured herein.

Natalia Mroczek-Sosnowska

2015-03-01

43

Nanoparticles of copper stimulate angiogenesis at systemic and molecular level.  

Science.gov (United States)

Copper is a key element affecting blood vessel growth and muscle development. However, the ions released from Cu salts are toxic. Given their specific physicochemical properties, nanoparticles of Cu (NanoCu) may have different bioactivity and affect the development of blood vessel and muscles in a different manner than Cu salts. The objective of the study was to evaluate the influence of NanoCu on embryo development and angiogenesis at the systemic and molecular level, in experiments using a chick embryo model. Fertilized chicken eggs were divided into a control group, and groups injected with a placebo, CuSO4 or NanoCu. Embryo development at the whole body level and molecular indices using an embryo chorioallantoic membrane model were measured during embryogenesis. The present study indicated for the first time that NanoCu have pro-angiogenic properties at the systemic level, to a greater degree than CuSO4 salt. The properties of NanoCu were confirmed at the molecular level, demonstrating significant effects on mRNA concentration and on mRNA gene expression of all pro-angiogenic and pro-proliferative genes measured herein. PMID:25741768

Mroczek-Sosnowska, Natalia; Sawosz, Ewa; Vadalasetty, Krishna Prasad; ?ukasiewicz, Monika; Niemiec, Jan; Wierzbicki, Mateusz; Kutwin, Marta; Jaworski, S?awomir; Chwalibog, André

2015-01-01

44

Molecular processes in plasmas collisions of charged particles with molecules  

CERN Document Server

Molecular Processes in Plasmas describes elementary collision processes in plasmas, particularly those involving molecules or molecular ions. Those collision processes (called molecular processes) maintain plasmas, produce reactive species and emissions, and play a key role in energy balance in plasmas or more specifically in determining the energy distribution of plasma particles. Many books on plasma physics mention the elementary processes, but normally rather briefly. They only touch upon the general feature or fundamental concept of the collision processes. On the other hand, there are many books on atomic and molecular physics, but most of them are too general or too detailed to be useful to people in the application fields. The present book enumerates all the possible processes in the collisions of electrons, as well as ions, with molecules. For each process, a compact but informative description of its characteristics is given together with illustrative examples. Since the author has much experience a...

Itikawa, Yukikazu

2007-01-01

45

Molecular Processing of Polymers with Cyclodextrins  

Science.gov (United States)

We summarize our recent studies employing the cyclic starch derivatives called cyclodextrins (CDs) to both nanostructure and functionalize polymers. Two important structural characteristics of CDs are taken advantage of to achieve these goals. First the ability of CDs to form noncovalent inclusion complexes (ICs) with a variety of guest molecules, including many polymers, by threading and inclusion into their relatively hydrophobic interior cavities, which are roughly cylindrical with diameters of ˜ 0.5 - 1.0 nm. ?-, ?-, and ?-CD contain six, seven, and eight ?-1,4-linked glucose units, respectively. Warm water washing of polymer-CD-ICs containing polymer guests insoluble in water or treatment with amylase enzymes serves to remove the host CDs and results in the coalescence of the guest polymers into solid samples. When guest polymers are coalesced from the CD-ICs by removing their host CDs, they are observed to solidify with structures, morphologies, and even conformations that are distinct from bulk samples made from their solutions and melts. Molecularly mixed, intimate blends of two or more polymers that are normally immiscible can be obtained from their common CD-ICs, and the phase segregation of incompatible blocks can be controlled (suppressed or increased) in CD-IC coalesced block copolymers. In addition, additives may be more effectively delivered to polymers in the form of their crystalline CD-ICs or soluble CD-rotaxanes. Secondly, the many hydroxyl groups attached to the exterior rims of CDs, in addition to conferring water solubility, provide an opportunity to covalently bond them to polymers either during their syntheses or via postpolymerization reactions. Polymers containing CDs in their backbones or attached to their side chains are observed to more readily accept and retain additives, such as dyes and fragrances. Processing with CDs can serve to both nanostructure and functionalize polymers, leading to greater understanding of their behaviors and to new properties and applications.

Tonelli, Alan E.

46

Level crossing in a molecular Cr{sub 8} ring  

Energy Technology Data Exchange (ETDEWEB)

The heat capacity of a molecular Cr{sub 8} ring was measured as a function of temperature and magnetic field in order to follow the evolution of the Schottky anomaly through the first (S=0 to |1,-1>) level crossing occurring at B{sub c1}=6.9 T. The results are interpreted within the framework of a spin Hamiltonian approach and they nicely fit the pattern of the energy levels derived by inelastic neutron spectroscopy. At B{sub c1}, the Schottky anomaly almost vanishes suggesting that a true crossing occurs in Cr{sub 8} in contrast to what was observed for ferric wheels.

Affronte, M. E-mail: affronte@unimore.it; Guidi, T.; Caciuffo, R.; Carretta, S.; Amoretti, G.; Hinderer, J.; Sheikin, I.; Smith, A.A.; Winpenny, R.E.P.; Slageren, J. van; Gatteschi, D

2004-05-01

47

Renormalized molecular levels in a Sc3N@C-80 molecular electronic device  

DEFF Research Database (Denmark)

We address several general questions about quantum transport through molecular systems by an ab initio analysis of a scandium-nitrogen doped C-80 metallofullerene device. Charge transfer from the Sc3N is found to drastically change the current-voltage characteristics: the current through the Sc3N @ C-80 device is double that through a bare C-80 device. We provide strong evidence that transport in such molecular devices is mediated by molecular electronic states which have been renormalized by the device environment, such as the electrodes and external bias V-b. The renormalized molecular levels and main transmission features shift in energy corresponding to half the applied bias voltage. This is also consistent with our finding that the voltage drops by V-b/2 at each molecule/electrode contact.

Larade, Brian; Taylor, Jeremy Philip

2001-01-01

48

Actinide geochemistry: From the molecular level to the real system  

Science.gov (United States)

Geochemical processes leading to either mobilization or retention of radionuclides in an aquifer system are significantly influenced by their interaction with rock, sediment and colloid surfaces. Therefore, a sound safety assessment of nuclear waste disposal requires the elucidation and quantification of those processes. State-of-the-art analytical techniques as e.g. laser- and X-ray spectroscopy are increasingly applied to study solid-liquid interface reactions to obtain molecular level speciation insight. We have studied the sorption of trivalent lanthanides and actinides onto aluminium oxides, hydroxides and purified clay minerals by the time-resolved laser fluorescence spectroscopy and X-ray-absorption spectroscopy. Chemical constitution and structure of surface bound actinides are proposed based on spectroscopic information. Open questions still remain with regard to the exact nature of mineral surface ligands and the mineral/water interface. Similarities of spectroscopic data obtained for M(III) sorbed onto ?-alumina, and clay minerals suggest the formation of very comparable inner-sphere surface complexes such as tbnd S-O-An(III)(OH) x(2 - x) (H 2O) 5 - x at pH > 5. Those speciation data are found consistent with those predicted by surface complexation modelling. The applicability of data obtained for pure mineral phases to actinide sorption onto heterogeneously composed natural clay rock is examined by experiments and by geochemical modelling. Good agreement of experiment and model calculations is found for U(VI) and trivalent actinide/lanthanide sorption to natural clay rock. The agreement of spectroscopy, geochemical modelling and batch experiments with natural rock samples and purified minerals increases the reliability in model predictions. The assessment of colloid borne actinide migration observed in various laboratory and field studies calls for detailed information on actinide-colloid interaction. Kinetic stabilization of colloid bound actinides can be due to inclusion into inorganic colloid matrix or by macromolecular rearrangement in case of organic, humic/fulvic like colloids. Only a combination of spectroscopy, microscopy and classical batch sorption experiments can help to elucidate the actinide-colloid interaction mechanisms and thus contribute to the assessment of colloids for radionuclide migration.

Geckeis, Horst; Rabung, Thomas

2008-12-01

49

Low level processing of diode spectrometry results  

International Nuclear Information System (INIS)

Systematic measurements in gamma spectrometry on slightly radioactive samples have led to study low levels existing in the spectra and to develop suitable processing methods. These methods and the advance that they represent in reading sensitivity are now applicable to all types of spectrum. The principles of this automatic reading are briefly summarized, leading to a description of the modifications which proved necessary to increase sensitivity. Three sample spectra are used to illustrate the arguments employed to achieve this result. The conclusions from the corresponding measurements provide a clearer understanding of the quality of the responses obtained during the initial reading. The application of these methods to systematic measurements is considered in the case of atmospheric aerosols. The owerall results obtained since 1969 are presented

50

Capillary leveling of stepped films with inhomogeneous molecular mobility  

CERN Document Server

A homogeneous thin polymer film with a stepped height profile levels due to the presence of Laplace pressure gradients. Here we report on studies of polymeric samples with precisely controlled, spatially inhomogeneous molecular weight distributions. The viscosity of a polymer melt strongly depends on the chain length distribution; thus, we learn about thin-film hydrodynamics with viscosity gradients. These gradients are achieved by stacking two films with different molecular weights atop one another. After a sufficient time these samples can be well described as having one dimensional viscosity gradients in the plane of the film, with a uniform viscosity normal to the film. We develop a hydrodynamic model that accurately predicts the shape of the experimentally observed self-similar profiles. The model allows for the extraction of a capillary velocity, the ratio of the surface tension and the viscosity, in the system. The results are in excellent agreement with capillary velocity measurements of uniform mono-...

McGraw, Joshua D; Bäumchen, Oliver; Raphaël, Elie; Dalnoki-Veress, Kari

2013-01-01

51

Key processes from tree to stand level  

International Nuclear Information System (INIS)

Changes in six factors have been identified as having potential major future impacts on the productivity and survival of forest trees and stands. These factors are atmospheric carbon dioxide concentration, tropospheric ozone concentration, mean annual air temperature and precipitation, extremes in temperature and precipitation, and levels of ultraviolet radiation. Except for precipitation, all of these factors are expected to increase with climatic change. However, the likelihood of their increase or change ranges from the given to the unknown. The way in which one or more of these factors might individually or in combination affect the productivity and survival of trees is discussed, and particularly sensitive physiological processes are identified. For example, increases in winter temperature and a doubling of CO2 will result in early budburst in many species and therefore increase the risk of frost damage. In other species or locations, warm winters may mean insufficient chilling hours and the requirements for release from bud dormancy may not be met. The interaction of these processes with current species distribution, genotype selection, and management alternatives is reviewed. 52 refs., 1 fig., 1 tab

52

Finding novel molecular connections between developmental processes and disease.  

Science.gov (United States)

Identifying molecular connections between developmental processes and disease can lead to new hypotheses about health risks at all stages of life. Here we introduce a new approach to identifying significant connections between gene sets and disease genes, and apply it to several gene sets related to human development. To overcome the limits of incomplete and imperfect information linking genes to disease, we pool genes within disease subtrees in the MeSH taxonomy, and we demonstrate that such pooling improves the power and accuracy of our approach. Significance is assessed through permutation. We created a web-based visualization tool to facilitate multi-scale exploration of this large collection of significant connections (http://gda.cs.tufts.edu/development). High-level analysis of the results reveals expected connections between tissue-specific developmental processes and diseases linked to those tissues, and widespread connections to developmental disorders and cancers. Yet interesting new hypotheses may be derived from examining the unexpected connections. We highlight and discuss the implications of three such connections, linking dementia with bone development, polycystic ovary syndrome with cardiovascular development, and retinopathy of prematurity with lung development. Our results provide additional evidence that TGFB lays a key role in the early pathogenesis of polycystic ovary syndrome. Our evidence also suggests that the VEGF pathway and downstream NFKB signaling may explain the complex relationship between bronchopulmonary dysplasia and retinopathy of prematurity, and may form a bridge between two currently-competing hypotheses about the molecular origins of bronchopulmonary dysplasia. Further data exploration and similar queries about other gene sets may generate a variety of new information about the molecular relationships between additional diseases. PMID:24874013

Park, Jisoo; Wick, Heather C; Kee, Daniel E; Noto, Keith; Maron, Jill L; Slonim, Donna K

2014-05-01

53

Improving Molecular Level Chemical Speciation of Organic Aerosols  

Science.gov (United States)

A substantial fraction of fine mode aerosols are organic with the majority formed in the atmosphere through oxidation of gas phase compounds emitted from a variety of natural and man-made sources. As a result, organic aerosols are comprised of thousands of individual organic species whose complexity increases exponentially with carbon number and degree of atmospheric oxidation. Chemical characterization of individual compounds present in this complex mixture provides information on sources and transformation processes that are critical for apportioning organic carbon from an often convoluted mixture of sources and to constrain oxidation mechanisms needed for atmospheric models. These compounds also affect the physical and optical properties of the aerosol but the vast majority remain unidentified and missing from published mass spectral libraries because of difficulties in separating and identifying them. We have developed improved methodologies for chemical identification in order to better understand complex environmental mixtures. Our approach has been to combine two-dimensional gas chromatography with high resolution time of flight mass spectrometry (GC×GC-HRTOFMS) and both traditional electron ionization (EI) and vacuum ultraviolet (VUV) photoionization. GC×GC provides improved separation of individual compounds over traditional one dimensional GC and minimizes co-elution of peaks resulting in mass spectra that are virtually free of interferences. VUV ionization is a ';soft' ionization technique that reduces fragmentation and enhances the abundance of the parent or molecular ion, which when combined with high resolution mass spectrometry can provide molecular formulas for chromatographic peaks. We demonstrate our methodology by applying it to identify more than 500 individual compounds in aerosol filter samples collected at Blodgett Forest, a rural site in the Sierra Nevada Mountains. Using the EI NIST mass spectral library and molecular formulas determined from the high resolution VUV analysis we characterized the observed peaks into those that were: (i) confidently identified by EI and confirmed by VUV (154 compounds), (ii) not matched by EI but assigned molecular formulas from VUV (230), (iii) EI matched but not confirmed by VUV (32), and (iv) not matched by EI and no molecular formula obtained from VUV (92). By combining the molecular formula information with both gas chromatography retention information and the EI mass fragmentation patterns it is possible to characterize previously unidentified compounds in chemically relevant functional group classes. Temporal patterns of all these tracers together provide a new and more complete lens through which to study SOA formation and transformation processes than has previously been possible.

Worton, D. R.; Decker, M.; Isaacman, G. A.; Chan, A.; Wilson, K. R.; Goldstein, A. H.

2013-12-01

54

Genomic Signal Processing: Predicting Basic Molecular Biological Principles  

Science.gov (United States)

Advances in high-throughput technologies enable acquisition of different types of molecular biological data, monitoring the flow of biological information as DNA is transcribed to RNA, and RNA is translated to proteins, on a genomic scale. Future discovery in biology and medicine will come from the mathematical modeling of these data, which hold the key to fundamental understanding of life on the molecular level, as well as answers to questions regarding diagnosis, treatment and drug development. Recently we described data-driven models for genome-scale molecular biological data, which use singular value decomposition (SVD) and the comparative generalized SVD (GSVD). Now we describe an integrative data-driven model, which uses pseudoinverse projection (1). We also demonstrate the predictive power of these matrix algebra models (2). The integrative pseudoinverse projection model formulates any number of genome-scale molecular biological data sets in terms of one chosen set of data samples, or of profiles extracted mathematically from data samples, designated the ``basis'' set. The mathematical variables of this integrative model, the pseudoinverse correlation patterns that are uncovered in the data, represent independent processes and corresponding cellular states (such as observed genome-wide effects of known regulators or transcription factors, the biological components of the cellular machinery that generate the genomic signals, and measured samples in which these regulators or transcription factors are over- or underactive). Reconstruction of the data in the basis simulates experimental observation of only the cellular states manifest in the data that correspond to those of the basis. Classification of the data samples according to their reconstruction in the basis, rather than their overall measured profiles, maps the cellular states of the data onto those of the basis, and gives a global picture of the correlations and possibly also causal coordination of these two sets of states. Mapping genome-scale protein binding data using pseudoinverse projection onto patterns of RNA expression data that had been extracted by SVD and GSVD, a novel correlation between DNA replication initiation and RNA transcription during the cell cycle in yeast, that might be due to a previously unknown mechanism of regulation, is predicted. (1) Alter & Golub, Proc. Natl. Acad. Sci. USA 101, 16577 (2004). (2) Alter, Golub, Brown & Botstein, Miami Nat. Biotechnol. Winter Symp. 2004 (www.med.miami.edu/mnbws/alter-.pdf)

Alter, Orly

2005-03-01

55

Photochemotherapy: Molecular And Cellular Processes Involved  

Science.gov (United States)

In photochemotherapy, as exemplified by the photodynamic therapy of tumors, a photosensitizing drug is administered to the patient; then, after a period of time to permit the most effective anatomical distribution of the drug, the diseased area is illuminated using an appropriate source of light of wavelengths absorbed by the sensitizer. In the tumor case, this results in the photochemical alteration of critical kinds of biornolecules in the diseased tissue, which interferes with the normal activities of certain cell organelles. This, in turn, leads to the injury or death of diseased cells in the treated area. This paper briefly reviews the reactive chemical species that can be formed in biological systems by illuminated sensitizers (triplet states of sensitizer molecules, free radicals of sensitizers and cellular components, singlet oxygen, superoxide, hydrogen peroxide, hydroxyl radical) and the kinds of biochemical changes they produce in essential cellular molecules (nucleic acids, proteins, unsaturated lipids, etc.). Also reviewed are the effects of these molecular changes on the structure and function of mammalian cell organelles (membranes, mitochondria, nuclear components, etc.) and the mechanisms of the resulting injury or killing of the cells.

Spikes, John D.

1989-03-01

56

Molecular epidemiology biomarkers-Sample collection and processing considerations  

International Nuclear Information System (INIS)

Biomarker studies require processing and storage of numerous biological samples with the goals of obtaining a large amount of information and minimizing future research costs. An efficient study design includes provisions for processing of the original samples, such as cryopreservation, DNA isolation, and preparation of specimens for exposure assessment. Use of standard, two-dimensional and nanobarcodes and customized electronic databases assure efficient management of large sample collections and tracking results of data analyses. Standard operating procedures and quality control plans help to protect sample quality and to assure validity of the biomarker data. Specific state, federal and international regulations are in place regarding research with human samples, governing areas including custody, safety of handling, and transport of human samples. Appropriate informed consent must be obtained from the study subjects prior to sample collection and confidentiality of results maintained. Finally, examples of three biorepositories of different scale (European Cancer Study, National Cancer Institute and School of Public Health Biorepository, University of California, Berkeley) are used to illustrate challenges faced by investigators and the ways to overcome them. New software and biorepository technologies are being developed by many companies that will help to bring biological banking to a new level required by molecular epidemiology of the 21st centurymiology of the 21st century

57

Using relaxation spectra to understand molecular processes in ring polymers  

Science.gov (United States)

Rheological characterization of polymeric systems can be used to investigate molecular processes. Some processes, such as entanglement and reptation, cannot be easily seen in the complex modulus or other conventional representations of rheological data. Instead, presenting data as relaxation spectra enhances the understanding of such processes. This will be shown on the example of ring and linear polystyrene polymers and ring/linear-blends, recently published by Kapnistos et al. (Nature Materials, 2008).

Stadler, Florian J.

2012-09-01

58

Information processing at single neuron level  

OpenAIRE

Based on numerical simulation of Hodgkin and Huxley type neuron stimulated from many synaptic inputs, an abstract concept of signal processing in individual neuron is proposed. In the concept proposed, neuron performs binding of synaptic inputs into a single output event, based on the degree of temporal coherence between the inputs. Inhibition serves as controlling factor of this type of binding.

Vidybida, A. K.

2007-01-01

59

1978 bibliography of atomic and molecular processes. [Bibliography  

Energy Technology Data Exchange (ETDEWEB)

This annotated bibliography lists 2557 works on atomic and molecular processes reported in publications dated 1978. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing are indexes of reactants and authors.

1980-03-01

60

1979 bibliography of atomic and molecular processes. [Bibliography  

Energy Technology Data Exchange (ETDEWEB)

This annotated bibliography lists 2146 works on atomic and molecular processes reported in publications dated 1979. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory, to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing are indexes of reactants and authors.

None

1980-08-01

61

Status of Safeguards and Separations Model Development at Plant and Molecular Levels  

International Nuclear Information System (INIS)

A primary goal of the Safeguards and Separations IPSC effort is the development of process modeling tools that allow dynamic simulations of separations plant operations under various configurations and conditions, and integration of relevant safeguards analyses. A requirement of the effort is to develop codes on modern, expandable architectures, with flexibility to explore and evaluate a wide range of process options. During FY09, efforts at ORNL have been focused on two priority tasks toward achieving the IPSC goal: (1) a top-down exploration of architecture - Subtask 1: Explore framework for code development and integration for plant-level simulation; and (2) a bottom-up fundamental modeling effort - Subtask 2: Development of molecular-level agent design code. Subtask 1 is important because definition and development of architecture is a key issue for the overall effort, as selection of an overall approach and code/data requirements is a necessary first step in the organization, design and development of separations and safeguards codes that will be incorporated. The agent design effort of Subtask 2 is a molecular-level modeling effort that has a direct impact on a near-term issue of the Separations and Waste Forms Campaign. A current focus of experimental efforts is the development of robust agents and processes for separation of Am/Cm. Development of enhanced agent-design codes will greatly accelerate discovery and experimental testing.ental testing.

62

Status of Safeguards and Separations Model Development at Plant and Molecular Levels  

Energy Technology Data Exchange (ETDEWEB)

A primary goal of the Safeguards and Separations IPSC effort is the development of process modeling tools that allow dynamic simulations of separations plant operations under various configurations and conditions, and integration of relevant safeguards analyses. A requirement of the effort is to develop codes on modern, expandable architectures, with flexibility to explore and evaluate a wide range of process options. During FY09, efforts at ORNL have been focused on two priority tasks toward achieving the IPSC goal: (1) a top-down exploration of architecture - Subtask 1: Explore framework for code development and integration for plant-level simulation; and (2) a bottom-up fundamental modeling effort - Subtask 2: Development of molecular-level agent design code. Subtask 1 is important because definition and development of architecture is a key issue for the overall effort, as selection of an overall approach and code/data requirements is a necessary first step in the organization, design and development of separations and safeguards codes that will be incorporated. The agent design effort of Subtask 2 is a molecular-level modeling effort that has a direct impact on a near-term issue of the Separations and Waste Forms Campaign. A current focus of experimental efforts is the development of robust agents and processes for separation of Am/Cm. Development of enhanced agent-design codes will greatly accelerate discovery and experimental testing.

de Almeida, Valmor F [ORNL; Hay, Benjamin [ORNL; DePaoli, David W [ORNL

2009-10-01

63

The requisite level of theory for the computational design of molecularly imprinted silica xerogels.  

Science.gov (United States)

The present manuscript reports the first application of molecular modelling to the design of molecularly imprinted polymers (MIPs) prepared by alkoxysilane sol-gel polymerization. The major goal was to determine the requisite level of theory for the selection of suitable alkoxysilane functional monomers. A comparative study, applied to the design of a MIP for beta-damascenone, involving different levels of theory, basis set superposition error (BSSE) correction and basis set augmentation and also semi-empirical methods, was performed. The computations results suggest that the use of the 3-21G basis set concomitantly with a method for BSSE correction represents a good compromise between theory level and computation time for the successful screening of functional monomers. Additionally, a few selected MIPs and their corresponding non-imprinted congeners (NIPs) were prepared and tested in the role of solid-phase extraction (SPE) sorbents. The confrontation of the computational results with the observed performance and morphological characteristics of the prepared MIPs suggest that besides the strength and type of interactions existing between template and functional monomers other concomitant features, related with the sol-gel process, must also be accounted for so that effective molecular imprinting is achieved in an alkoxysilane xerogel. Nevertheless, since an optimal template-functional monomer interaction is a necessary condition for successful imprinting, the choice of the best monomers is still of the greatest importance and the proposed computational method may constitute an expeditious and reliable screening tool. PMID:18396031

Azenha, Manuel; Kathirvel, Porkodi; Nogueira, Pedro; Fernando-Silva, António

2008-07-15

64

A Study of molecular cooling via Sisyphus processes  

CERN Document Server

We present a study of Sisyphus cooling of molecules: the scattering of a single-photon remove a substantial amount of the molecular kinetic energy and an optical pumping step allow to repeat the process. A review of the produced cold molecules so far indicates that the method can be implemented for most of them, making it a promising method able to produce a large sample of molecules at sub-mK temperature. Considerations of the required experimental parameters, for instance the laser power and linewidth or the trap anisotropy and dimensionality, are given. Rate equations, as well as scattering and dipolar forces, are solved using Kinetic Monte Carlo methods for several lasers and several levels. For NH molecules, such detailed simulation predicts a 1000-fold temperature reduction and an increase of the phase space density by a factor of 10^7 . Even in the case of molecules with both low Franck-Condon coefficients and a non-closed pumping scheme, 60% of trapped molecules can be cooled from 100 mK to sub-mK tem...

Comparat, Daniel

2014-01-01

65

Standardization of dosimetry in radiation processing level  

International Nuclear Information System (INIS)

First, the general state of the dosimetry for food irradiation, medical appliance sterilization and others and the development of various types of dosimeters are explained. The standardization of the dosimetry for radiation processing in Japan is behind that in Europe and USA. The radiation standards in Electrotechnical Laboratory and the research on the standardization in Japan Atomic Energy Research Institute are reported. Also the trend of the standardization in Europe and USA is shown. The primary standard for gamma ray is calorimeters and ionization chambers, and the latter has been used in Japan. With calorimeters, the absorbed dose by a specific substance can be directly measured. The standard dosimeters such as alanine dosimeter and the routine dosimeters utilizing the radiochemical reaction of plastics are explained. The 60Co gamma ray irradiation chamber in JAERI nearly satisfies the conditions for the calibration facility of ASTM. The traceability system and transfer dosimeters are described. The standardization of electron dosimetry has become a subject, and the evaluation of fuzziness in dosimetry is important for ensuring its reliability. (K.I.)

66

Unraveling the effect of the hydration level on the molecular mobility of nanolayered polymeric systems.  

Science.gov (United States)

This work investigates the influence of the hydration level on the molecular mobility and glass transition dynamics of freestanding chitosan/alginate (CHT/ALG) nanolayered systems. Nonconventional dynamic mechanical analysis identifies two relaxation processes assigned to the ?-relaxation of the two biopolymers, respectively, CHT and ALG, when immersed in water/ethanol mixtures. This phenomenon explains the shape memory properties of the multilayered systems induced by hydration, thus constituting promising smart materials that would be of paramount importance in a plethora of research fields, including in the biomedical and biotechnological fields. PMID:25639465

Borges, João; Caridade, Sofia G; Silva, Joana M; Mano, João F

2015-02-01

67

Melatonin combats molecular terrorism at the mitochondrial level.  

Science.gov (United States)

The intracellular environmental is a hostile one. Free radicals and related oxygen and nitrogen-based oxidizing agents persistently pulverize and damage molecules in the vicinity of where they are formed. The mitochondria especially are subjected to frequent and abundant oxidative abuse. The carnage that is left in the wake of these oxygen and nitrogen-related reactants is referred to as oxidative damage or oxidative stress. When mitochondrial electron transport complex inhibitors are used, e.g., rotenone, 1-methyl-1-phenyl-1,2,3,6-tetrahydropyridine, 3-nitropropionic acid or cyanide, pandemonium breaks loose within mitochondria as electron leakage leads to the generation of massive amounts of free radicals and related toxicants. The resulting oxidative stress initiates a series of events that leads to cellular apoptosis. To alleviate mitochondrial destruction and the associated cellular implosion, the cell has at its disposal a variety of free radical scavengers and antioxidants. Among these are melatonin and its metabolites. While melatonin stimulates several antioxidative enzymes it, as well as its metabolites (cyclic 3-hydroxymelatonin, N(1)-acetyl-N(2)-formyl-5-methoxykynuramine and N(1)-acetyl-5-methoxykynuramine), likewise effectively neutralize free radicals. The resulting cascade of reactions greatly magnifies melatonin's efficacy in reducing oxidative stress and apoptosis even in the presence of mitochondrial electron transport inhibitors. The actions of melatonin at the mitochondrial level are a consequence of melatonin and/or any of its metabolites. Thus, the molecular terrorism meted out by reactive oxygen and nitrogen species is held in check by melatonin and its derivatives. PMID:21218104

Reiter, Russel J; Paredes, Sergio D; Korkmaz, Ahmet; Jou, Mei-Jie; Tan, Dun-Xian

2008-09-01

68

Proceedings of the Conference on Isotopic and Molecular Processes  

International Nuclear Information System (INIS)

The proceedings of the Conference on Isotopic and Molecular Processes held on September 23 - 25, 1999 in Cluj - Napoca, Romania contains 8 plenary lectures, 12 oral presentations and 34 posters on isotopic processes (Section A) and 12 oral presentations plus 61 posters on molecular processes (Section B). The main topics treated in plenary lectures were isotope production, separation and enrichment as well as stable isotope applications. Also in this section studies on isotope effects in different fields are reported. In the section A, besides reports on isotope effects, exchange and separation, new methods of preparation and labelling compounds used particularly in nuclear medicine are presented. Also environmental studies by means of stable isotope and radon monitoring are described. In the section B several communications are treating the applications of radiation effects and different nuclear methods in medicine

69

Theoretical analysis of dynamic processes for interacting molecular motors  

Science.gov (United States)

Biological transport is supported by the collective dynamics of enzymatic molecules that are called motor proteins or molecular motors. Experiments suggest that motor proteins interact locally via short-range potentials. We investigate the fundamental role of these interactions by carrying out an analysis of a new class of totally asymmetric exclusion processes, in which interactions are accounted for in a thermodynamically consistent fashion. This allows us to explicitly connect microscopic features of motor proteins with their collective dynamic properties. A theoretical analysis that combines various mean-field calculations and computer simulations suggests that the dynamic properties of molecular motors strongly depend on the interactions, and that the correlations are stronger for interacting motor proteins. Surprisingly, it is found that there is an optimal strength of interactions (weak repulsion) that leads to a maximal particle flux. It is also argued that molecular motor transport is more sensitive to attractive interactions. Applications of these results for kinesin motor proteins are discussed.

Teimouri, Hamid; Kolomeisky, Anatoly B.; Mehrabiani, Kareem

2015-02-01

70

Atomic and molecular processes in JT-60U divertor plasmas  

Energy Technology Data Exchange (ETDEWEB)

Atomic and molecular data are indispensable for the understanding of the divertor characteristics, because behavior of particles in the divertor plasma is closely related to the atomic and molecular processes. In the divertor configuration, heat and particles escaping from the main plasma flow onto the divertor plate along the magnetic field lines. In the divertor region, helium ash must be effectively exhausted, and radiation must be enhanced for the reduction of the heat load onto the divertor plate. In order to exhaust helium ash effectively, the difference between behavior of neutral hydrogen (including deuterium and tritium) and helium in the divertor plasma should be understood. Radiation from the divertor plasma generally caused by the impurities which produced by the erosion of the divertor plate and/or injected by gas-puffing. Therefore, it is important to understand impurity behavior in the divertor plasma. The ions hitting the divertor plate recycle through the processes of neutralization, reflection, absorption and desorption at the divertor plates and molecular dissociation, charge-exchange reaction and ionization in the divertor plasma. Behavior of hydrogen, helium and impurities in the divertor plasmas can not be understood without the atomic and molecular data. In this report, recent results of the divertor study related to the atomic and molecular processes in JT-60U were summarized. Behavior of neural deuterium and helium was discussed in section 2. In section 3, the comparisons between the modelling of the carbon impurity transport and the measurements of C II and C IV were discussed. In section 4, characteristics of the radiative divertor using Ne puffing were reported. The new diagnostic method for the electron density and temperature in the divertor plasmas using the intensity ratios of He I lines was described in section 5. (author)

Takenaga, H.; Shimizu, K.; Itami, K. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment] [and others

1997-01-01

71

Chemodiversity and molecular plasticity: recognition processes as explored by property spaces.  

Science.gov (United States)

In the last few years, a need to account for molecular flexibility in drug-design methodologies has emerged, even if the dynamic behavior of molecular properties is seldom made explicit. For a flexible molecule, it is indeed possible to compute different values for a given conformation-dependent property and the ensemble of such values defines a property space that can be used to describe its molecular variability; a most representative case is the lipophilicity space. In this review, a number of applications of lipophilicity space and other property spaces are presented, showing that this concept can be fruitfully exploited: to investigate the constraints exerted by media of different levels of structural organization, to examine processes of molecular recognition and binding at an atomic level, to derive informative descriptors to be included in quantitative structure--activity relationships and to analyze protein simulations extracting the relevant information. Much molecular information is neglected in the descriptors used by medicinal chemists, while the concept of property space can fill this gap by accounting for the often-disregarded dynamic behavior of both small ligands and biomacromolecules. Property space also introduces some innovative concepts such as molecular sensitivity and plasticity, which appear best suited to explore the ability of a molecule to adapt itself to the environment variously modulating its property and conformational profiles. Globally, such concepts can enhance our understanding of biological phenomena providing fruitful descriptors in drug-design and pharmaceutical sciences. PMID:21707401

Vistoli, Giulio; Pedretti, Alessandro; Testa, Bernard

2011-06-01

72

Levels of processing: the evolution of a framework  

Scientific Electronic Library Online (English)

Full Text Available Although the levels of processing framework have evolved over its nearly 40 years of existence, the essence of the idea has not changed from the original. The original article published in 1972 suggests that in the encoding stage of a stimulus, there is a series of processing hierarchies ranging fro [...] m the shallowest level (perceptual processing-the subject initially perceives the physical and sensory characteristics of the stimulus) to the deepest level (semantic processing-related to pattern recognition and extraction of meaning). The depth processing is associated with high levels of retention and long-term memory traces. After extensive research and criticism, the authors added several concepts that aided in a better understanding of levels of processing framework and the items that subjects can recall such as transfer-appropriate processing and robust encoding. However, there are still some gaps in this framework that call for new scientific investigations, ranging from experimental paradigms with lists of words with healthy or pathological conditions subject to neuroimaging studies to confirm, refute or improve the framework. The aim of this article is to review the publications (articles and book chapters) dating from the original article to the present day to better understand the mnemonic process in terms of levels of processing and to highlight some of its contributions.

Roberta, Ekuni; Leonardo José, Vaz; Orlando Francisco Amodeo, Bueno.

2011-12-01

73

Molecular-Level Design of Heterogeneous Chiral Catalysis  

Energy Technology Data Exchange (ETDEWEB)

The following is a proposal to continue our multi-institutional research on heterogeneous chiral catalysis. Our team combines the use of surface-sensitive analytical techniques for the characterization of model systems with quantum and statistical mechanical calculations to interpret experimental data and guide the design of future research. Our investigation focuses on the interrelation among the three main mechanisms by which enantioselectivity can be bestowed to heterogeneous catalysts, namely: (1) by templating chirality via the adsorption of chiral supramolecular assemblies, (2) by using chiral modifiers capable of forming chiral complexes with the reactant and force enantioselective surface reactions, and (3) by forming naturally chiral surfaces using imprinting chiral agents. Individually, the members of our team are leaders in these various aspects of chiral catalysis, but the present program provides the vehicle to generate and exploit the synergies necessary to address the problem in a comprehensive manner. Our initial work has advanced the methodology needed for these studies, including an enantioselective titration procedure to identify surface chiral sites, infrared spectroscopy in situ at the interface between gases or liquids and solids to mimic realistic catalytic conditions, and DFT and Monte Carlo algorithms to simulate and understand chirality on surfaces. The next step, to be funded by the monies requested in this proposal, is to apply those methods to specific problems in chiral catalysis, including the identification of the requirements for the formation of supramolecular surface structures with enantioselective behavior, the search for better molecules to probe the chiral nature of the modified surfaces, the exploration of the transition from supramolecular to one-to-one chiral modification, the correlation of the adsorption characteristics of one-to-one chiral modifiers with their physical properties, in particular with their configuration, and the development of ways to imprint chiral centers on achiral solid surfaces. Chiral catalysis is not only a problem of great importance in its own right, but also the ultimate test of how to control selectivity in catalysis. The time is ripe for fundamental work in heterogeneous chiral catalysis to provide the U.S. with a leadership role in developing the next generation of catalytic processes for medicinal and agrochemical manufacturing. Our team provides the required expertise for a synergistic and comprehensive integration of physical and chemical experimentation with solid state and molecular reactivity theories to solve this problem.

Francisco Zaera

2012-03-21

74

Molecular-Level Design of Heterogeneous Chiral Catalysis  

International Nuclear Information System (INIS)

The following is a proposal to continue our multi-institutional research on heterogeneous chiral catalysis. Our team combines the use of surface-sensitive analytical techniques for the characterization of model systems with quantum and statistical mechanical calculations to interpret experimental data and guide the design of future research. Our investigation focuses on the interrelation among the three main mechanisms by which enantioselectivity can be bestowed to heterogeneous catalysts, namely: (1) by templating chirality via the adsorption of chiral supramolecular assemblies, (2) by using chiral modifiers capable of forming chiral complexes with the reactant and force enantioselective surface reactions, and (3) by forming naturally chiral surfaces using imprinting chiral agents. Individually, the members of our team are leaders in these various aspects of chiral catalysis, but the present program provides the vehicle to generate and exploit the synergies necessary to address the problem in a comprehensive manner. Our initial work has advanced the methodology needed for these studies, including an enantioselective titration procedure to identify surface chiral sites, infrared spectroscopy in situ at the interface between gases or liquids and solids to mimic realistic catalytic conditions, and DFT and Monte Carlo algorithms to simulate and understand chirality on surfaces. The next step, to be funded by the monies requested in this proposal, is to apply those methods to specific problems in chiral catalysis, including the identification of the requirements for the formation of supramolecular surface structures with enantioselective behavior, the search for better molecules to probe the chiral nature of the modified surfaces, the exploration of the transition from supramolecular to one-to-one chiral modification, the correlation of the adsorption characteristics of one-to-one chiral modifiers with their physical properties, in particular with their configuration, and the development of ways to imprint chiral centers on achiral solid surfaces. Chiral catalysis is not only a problem of great importance in its own right, but also the ultimate test of how to control selectivity in catalysis. The time is ripe for fundamental work in heterogeneous chiral catalysis to provide the U.S. with a leadership role in developing the next generation of catalytic processes for medicinal and agrochemical manufacturing. Our team provides the required expertise for a synergistic and comprehensive integration of physical and chemical experimentation with solid state and molecular reactivity theories to solve this problem.

75

Semiclassical theory of electronically nonadiabatic transitions in molecular collision processes  

Science.gov (United States)

An introductory account of the semiclassical theory of the S-matrix for molecular collision processes is presented, with special emphasis on electronically nonadiabatic transitions. This theory is based on the incorporation of classical mechanics with quantum superposition, and in practice makes use of the analytic continuation of classical mechanics into the complex space of time domain. The relevant concepts of molecular scattering theory and related dynamical models are described and the formalism is developed and illustrated with simple examples - collinear collision of the A+BC type. The theory is then extended to include the effects of laser-induced nonadiabatic transitions. Two bound continuum processes collisional ionization and collision-induced emission also amenable to the same general semiclassical treatment are discussed.

Lam, K. S.; George, T. F.

1979-01-01

76

Mesoscopic Properties of Molecular Folding and Aggregation Processes  

OpenAIRE

Protein folding, peptide aggregation and crystallization, as well as adsorption of molecules on soft or solid substrates have an essential feature in common: In all these processes, structure formation is guided by a collective, cooperative behavior of the molecular subunits lining up to build chainlike macromolecules. Proteins experience conformational transitions related to thermodynamic phase transitions. For chains of finite length, an important difference of crossovers ...

Bachmann, Michael; Janke, Wolfhard

2009-01-01

77

Simulation analysis of molecular laser isotope separation process for safeguards design  

International Nuclear Information System (INIS)

In this report, firstly an approach to a satisfactory safeguards concept is studied and proposed, among other things, as such that a process model should be developed only on a basis of published theories and data and that the safeguards should be designed using this process model. Secondly, as the first step of this approach, the photon-molecular reaction dynamics for a uranium-235-selective excitation process which is one of the infrared multi-photon dissociation processes for uranium enrichment was computer-simulated using a mathematical model as follows: through the investigation of a selective excitation probability in each energy level and of the transition probability to quasi-continuum levels from the top discrete level, a sensitivity analysis was carried out on the important parameters for process operations such as the optimum relative intensities between the laser for selective excitation and the laser for dissociation, the laser pulse widths to be required, and the asynchronous multi-laser irradiation. As a result, the conditions to be satisfied by such operational parameters in the design of photon-excited selective process were made clear. Although the dissociation process in the quasi-continuum and in the true continuum levels must be investigated in order to have a complete picture of the uranium-235 separation process, the optimization of the photon-excited selective process which was analyzed in this report is the most important theme for the molecular laser uranium enrichment and the detailed analysis of the characteristics of such excitation process not only gives fundamental data for the design of enrichment process but also is necessary for analyzing the diversion possibilities of producing higher enrichment than declared for safeguards design. (author)

78

THOREX processing and zeolite transfer for high-level waste stream processing blending  

International Nuclear Information System (INIS)

The West Valley Demonstration Project (WVDP) completed the pretreatment of the high-level radioactive waste (HLW) prior to the start of waste vitrification. The HLW originated form the two million liters of plutonium/uranium extraction (PUREX) and thorium extraction (THOREX) wastes remaining from Nuclear Fuel Services' (NFS) commercial nuclear fuel reprocessing operations at the Western New York Nuclear Service Center (WNYNSC) from 1966 to 1972. The pretreatment process removed cesium as well as other radionuclides from the liquid wastes and captured these radioactive materials onto silica-based molecular sieves (zeolites). The decontaminated salt solutions were volume-reduced and then mixed with portland cement and other admixtures. Nineteen thousand eight hundred and seventy-seven 270-liter square drums were filled with the cement-wastes produced from the pretreatment process. These drums are being stored in a shielded facility on the site until their final disposition is determined. Over 6.4 million liters of liquid HLW were processed through the pretreatment system. PUREX supernatant was processed first, followed by two PUREX sludge wash solutions. A third wash of PUREX/THOREX sludge was then processed after the neutralized THOREX waste was mixed with the PUREX waste. Approximately 6.6 million curies of radioactive cesium-137 (Cs-137) in the HLW liquid were removed and retained on 65,300 kg of zeolites. With pretreatment complete, the zeolite material has been mobilized, size-reduced (ground), and blended with the PUREX and THOREX sludges in a single feed tank that will supply the HLW slurry to the Vitrification Facility

79

Secondary ionization process in laser induced breakdown of molecular gases  

International Nuclear Information System (INIS)

We studied the separate effect of photo-ionization and collisional ionization of the molecular electronic excited states on the ionization growth rate of nitrogen irradiated with 10 ns pulse of Nd-YAG laser radiation at pressures 7.6x102, 1.79x103 and 5.34x103 Torr. It was found that photo-ionization processes play an important role in enhancing the ionization growth rate at pressures of 7.6x102 Torr. At higher pressures, where there is excess of electron density and hence excited molecule density, collisional ionization processes are dominant. (author). 6 refs, 3 figs

80

Mechanisms of molecular electronic rectification through electronic levels with strong vibrational coupling  

DEFF Research Database (Denmark)

We present a new view and an analytical formalism of electron flow through a donor-acceptor molecule inserted between a pair of metal electrodes. The donor and acceptor levels are strongly coupled to an environmental nuclear continuum. The formalism applies to molecular donor-acceptor systems both in vacuum or air, and in aqueous solution under electrochemical potential control. Multifarious patterns of rectified electron flow from the negatively to the positively biased electrode arise. The electronic interaction between the donor and acceptor fragments, mutually and with the electrodes, can be weak, corresponding to the fully diabatic limit. The rectification process then reduces to a sequence of vibrationally relaxed single-electron transfer steps. In the limits where the interactions are strong, denoted as the partially and fully adiabatic limits, the character of the rectification process is different, and electron flow proceeds coherently, without vibrational relaxation. In still another class of mechanisms the electronic level broadening of either donor or acceptor from the adjacent electrode is so strong that it is comparable to the vibrational broadening. The process then reduces to a three-level transition similar to STM of large redox molecules. Recent data for rectification in hexadecyl-quinolinium tricyanodimethanide monolayers by Metzger and co-workers [J. Am. Chem. Soc. 119, 10455 (1997); Acc. Chem. Res. 32, 950 (1999)], are discussed in terms of the reported views and formalism.

Kuznetsov, A.M.; Ulstrup, Jens

2002-01-01

81

Hierarchical Three-level Ontology for Text Processing  

OpenAIRE

The principal feature of ontology, which is developed for a text processing, is wider knowledge representation of an external world due to introduction of three-level hierarchy. It allows to improve semantic interpretation of natural language texts.

Gladun, Victor; Velychko, Vitalii; Svyatogor, Leonid

2008-01-01

82

High-Level Waste System Process Interface Description  

Energy Technology Data Exchange (ETDEWEB)

The High-Level Waste System is a set of six different processes interconnected by pipelines. These processes function as one large treatment plant that receives, stores, and treats high-level wastes from various generators at SRS and converts them into forms suitable for final disposal. The three major forms are borosilicate glass, which will be eventually disposed of in a Federal Repository, Saltstone to be buried on site, and treated water effluent that is released to the environment.

d' Entremont, P.D.

1999-01-14

83

Molecular and Supramolecular Information Processing From Molecular Switches to Unconventional Computing  

CERN Document Server

Edited by a renowned and much cited chemist, this book covers the whole span of molecular computers that are based on non-biological systems. The contributions by all the major scientists in the field provide an excellent overview of the latest developments in this rapidly expanding area. A must-have for all researchers working on this very hot topic. Perfectly complements Biomolecular Information Processing, also by Prof. Katz, and available as a two-volume set.

Katz, Evgeny

2012-01-01

84

Molecular Level Studies of the Metal/Atmosphere Interface  

OpenAIRE

The chemistry andphysics involved at the metal/atmosphereinterface is interesting both from a fundamental and an appliedperspective. Since iron is the most important of all metalsthis interface is of particular interest. The objective withthis thesis is to obtain new information on a molecular levelof the iron/atmosphere interface with a special emphasis on theinitial atmospheric corrosion. The work presented herein combines a large variety ofdifferent analytical surface science techniques. B...

Weissenrieder, Jonas

2003-01-01

85

The application of molecular genetics techniques to bioremediation processes  

Energy Technology Data Exchange (ETDEWEB)

Bioremediation is a process in which microorganisms are used to degrade toxic compounds. This technology has been used successfully to clean up a number of organic wastes including diesel fuel and creosote. Due to the increasingly stringent regulations affecting contaminated sites, a number of new technologies are being pursued that attempt to remediate wastes in situ, thus leaving the wastes undisturbed. One such pursuit has led to the proposal that molecular genetic techniques can be used to assess the genetic ecology of a contaminated waste site and that, subsequently, one can manipulate the indigenous microbial population so as to increase the biodegradation rate. Such a technology is heavily dependent on molecular genetic technique such as gene probing to determine the presence, distribution and ability of microbial genes to be expressed/amplified in the contaminated soil or water matrix. 117 refs., 14 figs., 13 tabs.

Alpert, S. (Alpert (S.), Palo Alto, CA (USA))

1989-12-01

86

High Level Waste (HLW) Feed Process Control Strategy  

Energy Technology Data Exchange (ETDEWEB)

The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system.

STAEHR, T.W.

2000-06-14

87

High-Level Waste (HLW) Feed Process Control Strategy  

International Nuclear Information System (INIS)

The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system

88

Ageing and photoageing of the skin: observations at the cellular and molecular level  

International Nuclear Information System (INIS)

It is now well established that ageing occurs at the level of individual cells in the skin and other organ systems. Changes in cell behaviour, protein production and gene expression in response to standardized stimuli are readily observed in cultured cells derived from young vs old donors and from photoaged vs sun-protected body sites. Whether these changes are best viewed as a cause or a consequence of ageing cannot be determined at present. Nevertheless, available data now provide cellular and molecular correlates for the well-known differences in clinical responsiveness between newborn, adult and photoaged skin. From this basis, it will hopefully be possible to develop a more comprehensive understanding of cutaneous ageing processes. (Author)

89

Molecular Level Investigations of Interfacial Friction of Polymer Brush Surfaces  

Science.gov (United States)

The development of synthetic polymer lubricants to mimic joint lubrication within the human body will be presented. Unlike most industrial applications involving oils and greases, lubrication of these joints is accomplished in an aqueous environment. Fundamentally, water is a poor lubricant in most settings due to the weak pressure dependence of its viscosity, yet the contacting surfaces of skeletal joints function with low friction throughout a lifetime. Motivated by the molecular structure of materials making up joint surfaces, interfacial friction between polymer brush surfaces under aqueous environments has been probed with an array of molecularly sensitive surface analytical techniques including atomic force microscopy. The brush surfaces, comprised of poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG), have been generated through the spontaneous adsorption of polymer from solution onto oxide substrates and sodium borosilicate surfaces (AFM tip). The character of the polymer films has been investigated in-situ with the quartz crystal microbalance (QCM) and atomic force microscope (AFM) and ex-situ with ellipsometry and X-ray photoelectron spectroscopy (XPS). The interfacial friction measurements have been carried out on polymer-coated substrates with bare or polymer-coated, microsphere-attached tips in over a range of solution conditions. It was found that the adsorption of polymer on oxides strikingly reduced the interfacial friction, resulting in ultra-low friction under certain conditions. By using a series of PLL-g-PEG polymers differing from each other in PEG side-chain length and grafting ratio, we observed that frictional properties of polymer-coated interfaces strongly depend on the architecture of PLL-g-PEG. Polymer-film formation and the influence of polymer architecture will be reviewed while the role of solvent and manifestation of ultra-low friction will be discussed in detail.

Perry, Scott

2005-03-01

90

0-level Vacuum Packaging RT Process for MEMS Resonators  

CERN Document Server

A new Room Temperature (RT) 0-level vacuum package is demonstrated in this work, using amorphous silicon (aSi) as sacrificial layer and SiO2 as structural layer. The process is compatible with most of MEMS resonators and Resonant Suspended-Gate MOSFET [1] fabrication processes. This paper presents a study on the influence of releasing hole dimensions on the releasing time and hole clogging. It discusses mass production compatibility in terms of packaging stress during back-end plastic injection process. The packaging is done at room temperature making it fully compatible with IC-processed wafers and avoiding any subsequent degradation of the active devices.

Abelé, N; Hibert, C; Casset, F; Ancey, P; Ionescu, A

2008-01-01

91

Coalescence process of two cooper nanoparticles: molecular dynamics simulation  

International Nuclear Information System (INIS)

Molecular Dynamics simulation, using an empirical potential EAM for the modeling of the atomic interaction, have been performed to study the coalescence process of two spherical Cu nanoparticles that contains equal number of atoms N = 736. The simulation is made with md step equal to 1.6 fs without applying periodic boundary conditions. The previously optimized nanoparticles has bounding energy -3.2805 eV/atom and melting temperature 989 K. The coalescence process with collision velocity of 400 and 800 m/s is analyzed at temperatures 300 and 600 K. The geometric and structural changes, that undergo particles during the collision process and sintering as well as the variation of number of atoms in the neck of the system are analyzed. It is observed that even at relatively low temperatures as 300 K nanoparticles are crowded together forming a single particle, but the final geometric form and the kinetic of the process is different at different temperatures and collision energies. The faceting surface of nanoparticles obeys the dynamics of the coalescence process. (author)

92

Simulation of deacidification process by molecular distillation of deodorizer distillate  

Scientific Electronic Library Online (English)

Full Text Available A computer program has been developed to simulate the deacidification of sunflower deodorizer distillate. The developed mathematical model is based on momentum, mass and energy balances. The Langmuir-Knudsen constitutive equation was used in order to represent the kinetics of evaporation and condens [...] ation. Physical and transport properties have been evaluated using correlations, which are functions of temperature and composition. The obtained partial differential equation system was solved by means of the Crank-Nicholson technique, and the calculation programs employed were developed and debugged using Matlab 7.1. The mathematical model was used to analyze the phenomena that take place during the molecular distillation process, and it also allowed studying the influence of operating variables on the performance of the process. In this investigation, we analyzed the influence of the operating temperature on purity and yield of the components. Trials at three evaporating temperatures (110 ºC, 130 ºC, and 140 ºC) were carried out in a KDL4 (UIC) molecular distillation apparatus to verify the model.

M. A., Marttinello; I., Leone; M., Pramparo.

2008-12-01

93

Effect of vacuum processing on outgassing within an orbiting molecular shield  

Science.gov (United States)

The limiting hydrogen number density in an orbiting molecular shield is highly dependent on the outgassing rates from the materials of construction for the shield, experimental apparatus, and other hardware contained within the shield. Ordinary degassing temperatures used for ultrahigh vacuum studies (less than 450 C) are not sufficient to process metals so that the contribution to the number density within the shield due to outgassing is less than the theoretically attainable level (approximately 200 per cu. cm). Pure aluminum and type 347 stainless steel were studied as candidate shield materials. Measurements of their hydrogen concentration and diffusion coefficients were made, and the effects of high temperature vacuum processing (greater than 600 C) on their resulting outgassing rates was determined. The densities in a molecular shield due to the outgassing from either metal were substantially less ( 0.003) than the density due to the ambient atomic hydrogen flux at an orbital altitude of 500 km.

Outlaw, R. A.

1982-01-01

94

Effect of Bread Making Process on Aflatoxin Level Changes  

Directory of Open Access Journals (Sweden)

Full Text Available Wheat flour is a commodity with a high risk of aflatoxins (AFs contamination. During the bread making there are many processes that can affect the AFs stability. The effect of bread making process using different yeast types on AFs levels was investigated. For this purpose, standards of AFs including B and Gwere added to flour and then bread loaves were prepared. Three types of commercially available yeast including active dry yeast, instant dry yeast and compressed yeast were used for dough preparation. AFs levels in flour, dough, and bread were analyzed by high performance liquid chromatography (HPLC with fluorescence detector. The results showed that maximum reduction in aflatoxin levels observed during first proof while the least decline was seen for the baking stage. The order of AFs reduction in bread making process was AFB1>AFB2>AFG1. Furthermore, the results indicated that the most effective yeast for AFs reduction was instant dry yeast.

Jafar Milani

2014-12-01

95

Method of processing high level radioactive liquid waste  

International Nuclear Information System (INIS)

High level radioactive liquid wastes formed from re-processing plants are cleaned being frozen in a freezing step. Frozen products of high level radioactive liquid wastes are put to a heated, pressurized and evacuated state in a sublimation step and nitric acid, water, subliming nuclides, etc. are sublimated from the frozen products. They are condensated in a condenser into liquid condensates. Then, a solution of sodium hydroxide is added to the residues and they are separated in a solid-liquid separation step into solutions such as of sodium nitrate and sodium hydroxide and residues mainly comprising nuclear fission products, actinoide elements and corrosion products in the re-processing step. Then, the residues are dried and calcined to form nitrates, drying and calcinating products, etc. of such shape and volume as easy to be stored. Accordingly, as compared with the case of directly processing high level radioactive liquid wastes, the amount of solidification products can be reduced remarkably. (I.N.)

96

Quantification of chromatin condensation level by image processing.  

Science.gov (United States)

The level of chromatin condensation is related to the silencing/activation of chromosomal territories and therefore impacts on gene expression. Chromatin condensation changes during cell cycle, progression and differentiation, and is influenced by various physicochemical and epigenetic factors. This study describes a validated experimental technique to quantify chromatin condensation. A novel image processing procedure is developed using Sobel edge detection to quantify the level of chromatin condensation from nuclei images taken by confocal microscopy. The algorithm was developed in MATLAB and used to quantify different levels of chromatin condensation in chondrocyte nuclei achieved through alteration in osmotic pressure. The resulting chromatin condensation parameter (CCP) is in good agreement with independent multi-observer qualitative visual assessment. This image processing technique thereby provides a validated unbiased parameter for rapid and highly reproducible quantification of the level of chromatin condensation. PMID:24099693

Irianto, Jerome; Lee, David A; Knight, Martin M

2014-03-01

97

Renormalization of Molecular Energy Levels in Single-Molecule Nanojunctions: An Ab-initio Approach  

Science.gov (United States)

Using first-principle calculations based on Density Functional Theory (DFT) in conjunction with the Non-Equilibrium Greens Functions (NEGF) technique, we have studied the effect of electrostatic environment in molecular energy levels of single-molecule transistors. This approach is applied to three polycyclic aromatic hydrocarbons (PAHs) anthracene, tetracene and pentacene, for calculating charging energies of molecular systems weakly coupled to an electrostatic environment. The result shows renormalization of molecular energy levels in an electrostatic environment. Further, it is observed that on increasing the number of aromatic rings, the addition energy value decreases which increases the conductivity of the system. Subsequently charge stability diagram for PAHs has been obtained.

Parashar, Sweta; Srivastava, Pankaj; Pattanaik, Manisha

2015-02-01

98

Level sets and extrema of random processes and fields  

CERN Document Server

A timely and comprehensive treatment of random field theory with applications across diverse areas of study Level Sets and Extrema of Random Processes and Fields discusses how to understand the properties of the level sets of paths as well as how to compute the probability distribution of its extremal values, which are two general classes of problems that arise in the study of random processes and fields and in related applications. This book provides a unified and accessible approach to these two topics and their relationship to classical theory and Gaussian processes and fields, and the most modern research findings are also discussed. The authors begin with an introduction to the basic concepts of stochastic processes, including a modern review of Gaussian fields and their classical inequalities. Subsequent chapters are devoted to Rice formulas, regularity properties, and recent results on the tails of the distribution of the maximum. Finally, applications of random fields to various areas of mathematics a...

Azais, Jean-Marc

2009-01-01

99

Document authentication at molecular levels using desorption atmospheric pressure chemical ionization mass spectrometry imaging.  

Science.gov (United States)

Molecular images of documents were obtained by sequentially scanning the surface of the document using desorption atmospheric pressure chemical ionization mass spectrometry (DAPCI-MS), which was operated in either a gasless, solvent-free or methanol vapor-assisted mode. The decay process of the ink used for handwriting was monitored by following the signal intensities recorded by DAPCI-MS. Handwritings made using four types of inks on four kinds of paper surfaces were tested. By studying the dynamic decay of the inks, DAPCI-MS imaging differentiated a 10-min old from two 4 h old samples. Non-destructive forensic analysis of forged signatures either handwritten or computer-assisted was achieved according to the difference of the contour in DAPCI images, which was attributed to the strength personalized by different writers. Distinction of the order of writing/stamping on documents and detection of illegal printings were accomplished with a spatial resolution of about 140 µm. A Matlab® written program was developed to facilitate the visualization of the similarity between signature images obtained by DAPCI-MS. The experimental results show that DAPCI-MS imaging provides rich information at the molecular level and thus can be used for the reliable document analysis in forensic applications. PMID:24078245

Li, Ming; Jia, Bin; Ding, Liying; Hong, Feng; Ouyang, Yongzhong; Chen, Rui; Zhou, Shumin; Chen, Huanwen; Fang, Xiang

2013-09-01

100

Regulation of leaf hydraulics: from molecular to whole plant levels  

OpenAIRE

The water status of plant leaves is dependent on both stomatal regulation and water supply from the vasculature to inner tissues. The present review addresses the multiple physiological and mechanistic facets of the latter process. Inner leaf tissues contribute to at least a third of the whole resistance to water flow within the plant. Physiological studies indicated that leaf hydraulic conductance (Kleaf) is highly dependent on the anatomy, development and age of the leaf and can vary rapidl...

Prado, Karine; Maurel, Christophe

2013-01-01

101

Molecular control of electron and hole transfer processes: Theory and applications  

Energy Technology Data Exchange (ETDEWEB)

Recent decades have seen remarkable advances in microscopic understanding of electron transfer (ET) processes in widely ranging contexts, including solid-state, liquid solution, and complex biological assemblies. The primary goal of this chapter is to report recent advances in the modeling, calculation, and analysis of electronic coupling in complex molecular aggregates, thereby allowing an assessment of current progress toward the goal of molecular-level control and design. The control of electron transfer kinetics (i.e., enhancing desired processes, while inhibiting others) involves, of course, system energetics (especially activation and reorganization energies) as well as electronic coupling, which is most directly relevant only after the system has reached the appropriate point (or region) along the reaction coordinate. Nevertheless, to focus the discussion in this chapter, the authors will consider such energetics, and the associated molecular and solvent coordinates which control then, only to the extent that they bear on the analysis of the electronic coupling. In the following sections they first discuss the formulation of basic ET models, including the definition of initial and final states, the role of orbitals and 1-particle models in a many-electron context, the utility of various effective Hamiltonians, and the role of vibronic as well as purely electronic effects. With these theoretical tools in hand, they then examine very recent applications to complex molecular systems using the techniques of computational quantum chemistry, followed by detailed analysis of the numerical results. They then conclude with some comments regarding the current ``state of the art`` and remaining challenges.

Newton, M.D. [Brookhaven National Lab., Upton, NY (United States). Dept. of Chemistry; Cave, R.J. [Harvey Mudd Coll., Claremont, CA (United States). Dept. of Chemistry

1996-02-01

102

Energy conversion processes based on molecular excited states  

Science.gov (United States)

In the past year significant progress has been made in three related areas. We have continued to develop new MLCT excited state systems. This work involves a combination of synthetic chemistry and photophysical measurements to elucidate excited state properties. In a second area, the synthetic chemistry has been developed for the attachment of metal-to-ligand charge transfer (MLCT) chromophores to a soluble 1:1 copolymer of styrene and p-chloromethylstyrene. The extent of loading of the chromophore or of electron or energy transfer quenchers can be varied systematically by controlling the preparative conditions. In a third area, our work has continued on the preparation of thin film molecular level assemblies which contain chromophore/quencher combinations, and the investigation of their properties. We have extended our earlier results on chemical binding in chlorosulfonated polystyrene films to a variety of organic or inorganic chromophores.

Meyer, Thomas J.

1989-02-01

103

High-Level waste process and product data annotated bibliography  

Energy Technology Data Exchange (ETDEWEB)

The objective of this document is to provide information on available issued documents that will assist interested parties in finding available data on high-level waste and transuranic waste feed compositions, properties, behavior in candidate processing operations, and behavior on candidate product glasses made from those wastes. This initial compilation is only a partial list of available references.

Stegen, G.E.

1996-02-13

104

Molecular and neural mechanisms of sex pheromone reception and processing in the silkmoth Bombyx mori  

Science.gov (United States)

Male moths locate their mates using species-specific sex pheromones emitted by conspecific females. One striking feature of sex pheromone recognition in males is the high degree of specificity and sensitivity at all levels, from the primary sensory processes to behavior. The silkmoth Bombyx mori is an excellent model insect in which to decipher the underlying mechanisms of sex pheromone recognition due to its simple sex pheromone communication system, where a single pheromone component, bombykol, elicits the full sexual behavior of male moths. Various technical advancements that cover all levels of analysis from molecular to behavioral also allow the systematic analysis of pheromone recognition mechanisms. Sex pheromone signals are detected by pheromone receptors expressed in olfactory receptor neurons in the pheromone-sensitive sensilla trichodea on male antennae. The signals are transmitted to the first olfactory processing center, the antennal lobe (AL), and then are processed further in the higher centers (mushroom body and lateral protocerebrum) to elicit orientation behavior toward females. In recent years, significant progress has been made elucidating the molecular mechanisms underlying the detection of sex pheromones. In addition, extensive studies of the AL and higher centers have provided insights into the neural basis of pheromone processing in the silkmoth brain. This review describes these latest advances, and discusses what these advances have revealed about the mechanisms underlying the specific and sensitive recognition of sex pheromones in the silkmoth. PMID:24744736

Sakurai, Takeshi; Namiki, Shigehiro; Kanzaki, Ryohei

2014-01-01

105

Solution processed molecular floating gate for flexible flash memories  

Science.gov (United States)

Solution processed fullerene (C60) molecular floating gate layer has been employed in low voltage nonvolatile memory device on flexible substrates. We systematically studied the charge trapping mechanism of the fullerene floating gate for both p-type pentacene and n-type copper hexadecafluorophthalocyanine (F16CuPc) semiconductor in a transistor based flash memory architecture. The devices based on pentacene as semiconductor exhibited both hole and electron trapping ability, whereas devices with F16CuPc trapped electrons alone due to abundant electron density. All the devices exhibited large memory window, long charge retention time, good endurance property and excellent flexibility. The obtained results have great potential for application in large area flexible electronic devices. PMID:24172758

Zhou, Ye; Han, Su-Ting; Yan, Yan; Huang, Long-Biao; Zhou, Li; Huang, Jing; Roy, V. A. L.

2013-01-01

106

Graphics processing units accelerated semiclassical initial value representation molecular dynamics  

Science.gov (United States)

This paper presents a Graphics Processing Units (GPUs) implementation of the Semiclassical Initial Value Representation (SC-IVR) propagator for vibrational molecular spectroscopy calculations. The time-averaging formulation of the SC-IVR for power spectrum calculations is employed. Details about the GPU implementation of the semiclassical code are provided. Four molecules with an increasing number of atoms are considered and the GPU-calculated vibrational frequencies perfectly match the benchmark values. The computational time scaling of two GPUs (NVIDIA Tesla C2075 and Kepler K20), respectively, versus two CPUs (Intel Core i5 and Intel Xeon E5-2687W) and the critical issues related to the GPU implementation are discussed. The resulting reduction in computational time and power consumption is significant and semiclassical GPU calculations are shown to be environment friendly.

Tamascelli, Dario; Dambrosio, Francesco Saverio; Conte, Riccardo; Ceotto, Michele

2014-05-01

107

Graphics processing units accelerated semiclassical initial value representation molecular dynamics  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a Graphics Processing Units (GPUs) implementation of the Semiclassical Initial Value Representation (SC-IVR) propagator for vibrational molecular spectroscopy calculations. The time-averaging formulation of the SC-IVR for power spectrum calculations is employed. Details about the GPU implementation of the semiclassical code are provided. Four molecules with an increasing number of atoms are considered and the GPU-calculated vibrational frequencies perfectly match the benchmark values. The computational time scaling of two GPUs (NVIDIA Tesla C2075 and Kepler K20), respectively, versus two CPUs (Intel Core i5 and Intel Xeon E5-2687W) and the critical issues related to the GPU implementation are discussed. The resulting reduction in computational time and power consumption is significant and semiclassical GPU calculations are shown to be environment friendly.

Tamascelli, Dario; Dambrosio, Francesco Saverio [Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); Conte, Riccardo [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States); Ceotto, Michele, E-mail: michele.ceotto@unimi.it [Dipartimento di Chimica, Università degli Studi di Milano, via Golgi 19, 20133 Milano (Italy)

2014-05-07

108

Doping-induced realignment of molecular levels at organic organic heterojunctions  

Science.gov (United States)

This article examines how the concept of alignment of charge neutrality levels (CNL) can be used to explain and predict interface dipole and molecular level offset at organic-organic (OO) heterojunctions. The application of the model of CNL alignment to interfaces between undoped materials is reviewed first. The model is then extended to explain the shift of the CNL upon electrical doping of an organic material, and the resulting change in interface dipole and molecular level alignment. This approach provides, at this point, the first comprehensive prediction of energetics at OO heterojunctions.

Kahn, Antoine; Zhao, Wei; Gao, Weiying; Vázquez, Hector; Flores, Fernando

2006-06-01

109

INTEGRATING CMMI MATURITY LEVEL-3 IN TRADITIONAL SOFTWARE DEVELOPMENT PROCESS  

Directory of Open Access Journals (Sweden)

Full Text Available CMMI defines the practices that are specially implemented by software development businesses to achievesuccess. Practices includes topics that direct about eliciting and managing requirements, decision making,measuring performance, planning work, handling risks, and more. In this paper we will discuss CapabilityMaturity Model Integration (CMMI software process improvement maturity model and the process areasat various levels of CMMI in brief. The main emphasis of the paper is to discuss about the RiskManagement (RSKM which is one of process area at CMMI level-3. The purpose of Risk Management(RSKM processes is to identify potential problems before they occur so that risk-handling activities can beplanned and invoked as needed across the life of the product or project to mitigate adverse impacts onachieving objectives. The main aim of the paper is to analyse the effect of integrating the CMMI maturitylevel-3(process area -RSKM with the traditional software development process. It represents an attempt toorganize the sources of software development risk around the principal aspects of the softwaredevelopment cycle.

Reena Dadhich

2012-02-01

110

Effect of the bread-making process on zearalenone levels.  

Science.gov (United States)

The effects of the bread-making process including fermentation with Saccharomyces cerevisiae and lactic acid bacteria (Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus acidophilus and Lactobacillus fermentum) and baking at 200°C on zearalenone (ZEA) levels were investigated. Standard solutions of ZEA were added to flour and then loaves of bread were prepared. Sourdough and three types of yeast including active dry yeast, instant dry yeast and compressed yeast were used for the fermentation of dough. ZEA levels in flour, dough and bread were determined by HPLC with fluorescence detection after extraction and clean-up on an immunoaffinity column. The highest reduction in levels of ZEA was found in the first fermentation (first proof), while the lowest reduction was observed in the baking stage. In addition, the results showed that compressed yeast had the maximum reduction potential on ZEA levels even at the baking stage. PMID:25291600

Heidari, Sara; Milani, Jafar; Nazari, Seyed Saman Seyed Jafar

2014-01-01

111

Low level radwaste management and processing in Maanshan NPP  

International Nuclear Information System (INIS)

Nuclear power plant like as the other power plant will generate technology waste. Owing to Nuclear still is a debatable topic for discussion, Nuclear radwaste including low level radwaste, high level spent fuel and nuclear operate safety become a focus point in Taiwan also in all world. Maanshan NPP is the only one PWR unit in Taiwan. In common understand, the Low Level radwaste generate from PWR unit is less than BWR. No matter what LLW generate quantity is reduced obviously, the government asks seriously restrain LLW quantity year by year. Maanshan NPP had reach a stable level in solidification waste, system spent resin, combustible and incombustible radwaste that generate from necessary maintenance. The further aim is keep waste generate under control, stable operate processing system and make a new processing technical to dispose spent resin. Maanshan NPP via technical cooperation to set HESS system with INER in one decade. Nowadays there are about 18 55 gallon drums per year in Maanshan NPP. LLW incinerator equipment designed by Maanshan and install at 7 years ago, there almost burns up all the combustible LLW that generate from commercial operation. The new equipment, wet-oxidation solidification process for treatment of spent radioactive ion-exchange resins plan will cooperate with INER and complete in 2014. It is estimated that the generation of solidified wastes of the NPS will be reduced to about 1/3 volume of that currently generated. (author)urrently generated. (author)

112

Vibrational spectroscopy for probing molecular-level interactions in organic films mimicking biointerfaces.  

Science.gov (United States)

Investigation into nanostructured organic films has served many purposes, including the design of functionalized surfaces that may be applied in biomedical devices and tissue engineering and for studying physiological processes depending on the interaction with cell membranes. Of particular relevance are Langmuir monolayers, Langmuir-Blodgett (LB) and layer-by-layer (LbL) films used to simulate biological interfaces. In this review, we shall focus on the use of vibrational spectroscopy methods to probe molecular-level interactions at biomimetic interfaces, with special emphasis on three surface-specific techniques, namely sum frequency generation (SFG), polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) and surface-enhanced Raman scattering (SERS). The two types of systems selected for exemplifying the potential of the methods are the cell membrane models and the functionalized surfaces with biomolecules. Examples will be given on how SFG and PM-IRRAS can be combined to determine the effects from biomolecules on cell membrane models, which include determination of the orientation and preservation of secondary structure. Crucial information for the action of biomolecules on model membranes has also been obtained with PM-IRRAS, as is the case of chitosan removing proteins from the membrane. SERS will be shown as promising for enabling detection limits down to the single-molecule level. The strengths and limitations of these methods will also be discussed, in addition to the prospects for the near future. PMID:24530000

Volpati, Diogo; Aoki, Pedro H B; Alessio, Priscila; Pavinatto, Felippe J; Miranda, Paulo B; Constantino, Carlos J L; Oliveira, Osvaldo N

2014-05-01

113

CELLmicrocosmos - Integrative cell modeling at the  molecular, mesoscopic and functional level  

OpenAIRE

The modeling of cells is an important application area of Systems Biology. In the context of this work, three cytological levels are defined: the mesoscopic, the molecular and the functional level. A number of related approaches which are quite diverse will be introduced during this work which can be categorized into these disciplines. But none of these approaches covers all areas. In this work, the combination of all three aforementioned cytological levels is presented, realized by the CELLm...

Sommer, Bjo?rn

2012-01-01

114

Probing charge transport of ruthenium-complex-based molecular wires at the single-molecule level.  

Science.gov (United States)

A ruthenium(II) bis(sigma-arylacetylide)-complex-based molecular wire functionalized with thiolacetyl alligator clips at both ends (OPERu) was used to fabricate gold substrate-molecular wire-conductive tip junctions. To elucidate the ruthenium-complex-enhanced charge transport, we conducted a single-molecule level investigation using the technique-combination method, where electronic decay constant, single-molecular conductance, and barrier height were obtained by scanning tunneling microscopy (STM) apparent height measurements, STM break junction measurements, and conductive probe-atomic force microscopy (CP-AFM) measurements, respectively. A quantitative comparison of OPERu with the well-studied pi-conjugated molecular wire oligo(1,4-phenylene ethynylene) (OPE) indicated that the lower electronic decay constant as well as the higher conductance of OPERu resulted from its lower band gap between the highest occupied molecular orbital (HOMO) and the gold Fermi level. The small offset of 0.25 eV was expected to be beneficial for the long-range charge transport of molecular wires. Moreover, the observed cross-platform agreement proved that this technique-combination method could serve as a benchmark for the detailed description of charge transport through molecular wires. PMID:19206398

Liu, Ke; Wang, Xianhong; Wang, Fosong

2008-11-25

115

Ab initio quantum mechanical/molecular mechanical simulation of electron transfer process: Fractional electron approach  

International Nuclear Information System (INIS)

Electron transfer (ET) reactions are one of the most important processes in chemistry and biology. Because of the quantum nature of the processes and the complicated roles of the solvent, theoretical study of ET processes is challenging. To simulate ET processes at the electronic level, we have developed an efficient density functional theory (DFT) quantum mechanical (QM)/molecular mechanical (MM) approach that uses the fractional number of electrons as the order parameter to calculate the redox free energy of ET reactions in solution. We applied this method to study the ET reactions of the aqueous metal complexes Fe(H2O)62+/3+ and Ru(H2O)62+/3+. The calculated oxidation potentials, 5.82 eV for Fe(II/III) and 5.14 eV for Ru(II/III), agree well with the experimental data, 5.50 and 4.96 eV, for iron and ruthenium, respectively. Furthermore, we have constructed the diabatic free energy surfaces from histogram analysis based on the molecular dynamics trajectories. The resulting reorganization energy and the diabatic activation energy also show good agreement with experimental data. Our calculations show that using the fractional number of electrons (FNE) as the order parameter in the thermodynamic integration process leads to efficient sampling and validate the ab initio QM/MM approach in the calculation of redox free energies

116

Synergistic erosion process of hydrocarbon films: a molecular dynamics study  

International Nuclear Information System (INIS)

Fundamental processes leading to the erosion of hydrocarbon films due to energetic argon ions and hydrogen atoms have been investigated using molecular dynamics simulations. A generic mechanism has been identified for carbon erosion due to energetic (150 eV) argon ions in the presence of sub-eV hydrogen atoms. This surface erosion process, which we call hydrogen enhanced physical sputtering (HEPS), is primarily a physical sputtering mechanism, enhanced due to the screening effect of hydrogen atoms. The energetic argon ions create open bonds within their penetration range. The hydrogen atoms passivate the open bonds created within the first few atomic layers. Subsequent ion bombardment causes the breaking of C-C bonds within and beyond the H penetration range. The steric effect of H atoms bound to the top layer of carbon atoms prevents the re-attachment of the broken bonds, and this leads to unsaturated molecule emission from the surface. The kinetic energy of the emitted molecules is above thermal energy and the emission takes place within 5 ps after the ion impact

117

Commercial low level waste processing in a competitive market  

International Nuclear Information System (INIS)

In most nations with active nuclear establishments, Low Level Radioactive Waste (LLW) is treated, packaged and disposed of by a single governmental organization or corporation that operates in a monopoly situation. In the US, LLW generated from utility and industry sources is processed at various commercial enterprises throughout the country and buried in commercially owned and operated LLW disposal facilities. These centralized waste processing or 'fixed base' companies provide their services in a competitive, free market environment. This competition has led to the development and use of effective technologies for waste volume reduction. The actual techniques used are chosen based on cost impact to company's financial performance rather than budget considerations

118

Recovery of thorium from high level raffinate from Thorex process  

International Nuclear Information System (INIS)

Solvent extraction process for the recovery of thorium from high level waste of Thorex origin is studied. Both batch and counter-current extraction studies were carried out using 38% tri-n-butyl phosphate in normal paraffin. By maintaining aqueous to organic phase ratio of 1:3, third phase formation was avoided. Quantitative extraction of thorium was achieved in six stages of extraction. The extracted thorium could be stripped using dilute nitric acid (0.001 M). (author)

119

Molecular rocket and implantation reactions: shock-induced phenomena at atomic and molecular levels  

International Nuclear Information System (INIS)

Molecular rocket reactions are unique but contain important features. This paper deals with their relation to shock-induced phenomena. Extraction of metallocene from a cavity of cyclodextrin is assisted by shock of collision and is followed by rearrangement reactions. Severeness of the rearrangement depends on energy. Collisions of implanted atoms also extract metallocene molecules from inclusion compounds to cause rearrangement reactions. This is ascribed to a shock-induced phenomenon. Collision cascade enhancement of the yield in implantation reaction is closely related to shock waves generated after the implanted atom. Forward pressure pushes the implanted atom and reactant molecules into the microcrack formed in implantation in metal ?-diketonates. In the case of metallocene implantation, however, another mechanism involving an increased number of replacement paths should be considered. (orig.)

120

Prediction of organic molecular crystal geometries from MP2-level fragment quantum mechanical/molecular mechanical calculations  

Science.gov (United States)

The fragment-based hybrid many-body interaction (HMBI) model provides a computationally affordable means of applying electronic structure wavefunction methods to molecular crystals. It combines a quantum mechanical treatment of individual molecules in the unit cell and their short-range pairwise interactions with a polarizable molecular mechanics force-field treatment of long-range and many-body interactions. Here, we report the implementation of analytic nuclear gradients for the periodic model to enable full relaxation of both the atomic positions and crystal lattice parameters. Using a set of five, chemically diverse molecular crystals, we compare the quality of the HMBI MP2/aug-cc-pVDZ-level structures with those obtained from dispersion-corrected periodic density functional theory, B3LYP-D*, and from the Amoeba polarizable force field. The MP2-level structures largely agree with the experimental lattice parameters to within 2%, and the root-mean-square deviations in the atomic coordinates are less than 0.2 Å. These MP2 structures are almost as good as those predicted from periodic B3LYP-D*/TZP and are significantly better than those obtained with B3LYP-D*/6-31G(d,p) or with the Amoeba force field.

Nanda, Kaushik D.; Beran, Gregory J. O.

2012-11-01

121

Defense Waste Processing Facility: a remote process for solidification of Savannah River Plant high level waste  

International Nuclear Information System (INIS)

The Department of Energy is proposing that a Defense Waste Processing Facility be built at the Savannah River Plant (SRP) to remotely process and immobilize high level radioactive waste produced at the site. Research, development, and design of the facility is being provided by a multidisciplined task force of personnel from the Du Pont Company which designed, built and has operated SRP since 1950. This remotely operated facility will immobilize 28 million gallons of high level waste now stored in tanks, plus the waste to be generated from continued reprocessing operations. Borosilicate glass has been selected as the reference waste form for the immobilization process

122

Some implications of partitioning processes for high level waste  

International Nuclear Information System (INIS)

The concept of partitioning and transmutation (P/T) of actinides is based on the removal of long-lived actinides from high level waste (HLW) before it is vitrified, and their incineration. The argument for P/T is that it reduces the long-term toxicity of vitrified HLW. The more significant criterion of its effect on the radiological dose to mankind resulting from releases from the repository also needs to be addressed. Considerations of the long-term radiotoxicity of the radionuclides present in HLW, and also of their radiological dose implications, lead to the conclusion that the important chemical elements that need to be removed from HLW in an effective P/T strategy are: Np, Pu, Am and Tc. Zirconium should also be considered, because of the long half-life of the isotope 93Zr. The performance of alternative processes needs to be judged against their effectiveness in removing these elements. Candidate processes for the partitioning of HLW have been analysed, in as quantitative a manner as data permit. None of them can achieve a perfect separation. The processes require plant and equipment of comparable scale to the chemical separation section of the original reprocessing plant. The actinide products are obtained in high volume aqueous streams, which would require further processing to provide targets for incineration or transmutation. Secondary waste streams containing actinides will be produced from the partitioning processes and also from the subsequent ng processes and also from the subsequent treatment of the products and the fabrication of targets. These secondary wastes may present new problems in waste management and should be considered in a comparative assessment of alternative processes. It is concluded that P/T remains a complex and expensive process that would change, but not improve, current waste management strategies. (authors)

123

In situ sensing and modeling of molecular events at the cellular level  

Science.gov (United States)

We developed the Atomic Force Microscopy (AFM) based nanorobot in combination with other nanomechanical sensors for the investigation of cell signaling pathways. The AFM nanorobotics hinge on the superior spatial resolution of AFM in imaging and extends it into the measurement of biological processes and manipulation of biological matters. A multiple input single output control system was designed and implemented to solve the issues of nanomanipulation of biological materials, feedback, response frequency and nonlinearity. The AFM nanorobotic system therefore provide the human-directed position, velocity and force control with high frequency feedback, and more importantly it can feed the operator with the real-time imaging of manipulation result from the fast-imaging based local scanning. The use of the system has taken the study of cellular process at the molecular scale into a new level. The cellular response to the physiological conditions can be significantly manifested in cellular mechanics. Dynamic mechanical property has been regarded as biomarkers, sometimes even regulators of the signaling and physiological processes, thus the name mechanobiology. We sought to characterize the relationship between the structural dynamics and the molecular dynamics and the role of them in the regulation of cell behavior. We used the AFM nanorobotics to investigate the mechanical properties in real-time of cells that are stimulated by different chemical species. These reagents could result in similar ion channel responses but distinctive mechanical behaviors. We applied these measurement results to establish a model that describes the cellular stimulation and the mechanical property change, a "two-hit" model that comprises the loss of cell adhesion and the initiation of cell apoptosis. The first hit was verified by functional experiments: depletion of Calcium and nanosurgery to disrupt the cellular adhesion. The second hit was tested by a labeling of apoptotic markers that were revealed by flow cytometry. The model would then be able to decipher qualitatively the molecular dynamics infolded in the regulation of cell behavior. To decipher the signaling pathway quantitatively, we employed a nanomechanical sensor at the bottom of the cell, quartz crystal microbalance with energy dissipation monitoring (QCM-D) to monitor the change at the basal area of the cell. This would provide the real time focal adhesion information and would be used in accordance with the AFM measurement data on the top of the cell to build a more complete mechanical profile during the antibody induced signaling process. We developed a model from a systematic control perspective that considers the signaling cascade at certain stimulation as the controller and the mechanical and structural interaction of the cell as the plant. We firstly derived the plant model based on QCM-D and AFM measurement processes. A signaling pathway model was built on a grey box approach where part of the pathway map was delineated in detail while others were condensed into a single reaction. The model parameters were obtained by extracting the mechanical response from the experiment. The model refinements were conducted by testing a series of inhibition mechanisms and comparing the simulation data with the experimental data. The model was then used to predict the existences of certain reactions that are qualitatively reported in the literature.

Yang, Ruiguo

124

Dynamics of Molecular Motors with Finite Processivity on Heterogeneous Tracks  

CERN Document Server

The dynamics of molecular motors which occasionally detach from a heterogeneous track like DNA or RNA is considered. Motivated by recent single molecule experiments, we study a simple model for a motor moving along a disordered track using chemical energy while an external force opposes its motion. The motors also have finite processivity, i.e., they can leave the track with a position dependent rate. We show that the response of the system to disorder in the hopping off rate depends on the value of the external force. For most values of the external force, strong disorder causes the motors which survive for long times on the track to be localized at preferred positions. However, near the stall force, localization occurs for any amount of disorder. Existence of localized states near the top of the band implies a stretched exponential contribution to the decay of the survival probability. To obtain these results, we study the complex eigenvalue spectrum of the time evolution operator. A similar spectral analys...

Kafri, Y; Nelson, D R; Kafri, Yariv; Lubensky, David K.; Nelson, David R.

2004-01-01

125

Molecular evolution across the Asteraceae: micro- and macroevolutionary processes.  

Science.gov (United States)

The Asteraceae (Compositae) is a large family of over 20,000 wild, weedy, and domesticated species that comprise approximately 10% of all angiosperms, including annual and perennial herbs, shrubs and trees, and species on every continent except Antarctica. As a result, the Asteraceae provide a unique opportunity to understand the evolutionary genomics of lineage radiation and diversification at numerous phylogenetic scales. Using publicly available expressed sequence tags from 22 species representing four of the major Asteraceae lineages, we assessed neutral and nonneutral evolutionary processes across this diverse plant family. We used bioinformatic tools to identify candidate genes under selection in each species. Evolution at silent and coding sites were assessed for different Gene Ontology functional categories to compare rates of evolution over both short and long evolutionary timescales. Our results indicate that patterns of molecular change across the family are surprisingly consistent on a macroevolutionary timescale and much more so more than would be predicted from the analysis of one (or many) examples of microevolution. These analyses also point to particular classes of genes that may be crucial in shaping the radiation of this diverse plant family. Similar analyses of nuclear and chloroplast genes in six other plant families confirm that many of these patterns are common features of the plant kingdom. PMID:21693439

Kane, Nolan C; Barker, Michael S; Zhan, Shing H; Rieseberg, Loren H

2011-12-01

126

Process Design Concepts for Stabilization of High Level Waste Calcine  

Energy Technology Data Exchange (ETDEWEB)

The current baseline assumption is that packaging ¡§as is¡¨ and direct disposal of high level waste (HLW) calcine in a Monitored Geologic Repository will be allowed. The fall back position is to develop a stabilized waste form for the HLW calcine, that will meet repository waste acceptance criteria currently in place, in case regulatory initiatives are unsuccessful. A decision between direct disposal or a stabilization alternative is anticipated by June 2006. The purposes of this Engineering Design File (EDF) are to provide a pre-conceptual design on three low temperature processes under development for stabilization of high level waste calcine (i.e., the grout, hydroceramic grout, and iron phosphate ceramic processes) and to support a down selection among the three candidates. The key assumptions for the pre-conceptual design assessment are that a) a waste treatment plant would operate over eight years for 200 days a year, b) a design processing rate of 3.67 m3/day or 4670 kg/day of HLW calcine would be needed, and c) the performance of waste form would remove the HLW calcine from the hazardous waste category, and d) the waste form loadings would range from about 21-25 wt% calcine. The conclusions of this EDF study are that: (a) To date, the grout formulation appears to be the best candidate stabilizer among the three being tested for HLW calcine and appears to be the easiest to mix, pour, and cure. (b) Only minor differences would exist between the process steps of the grout and hydroceramic grout stabilization processes. If temperature control of the mixer at about 80„aC is required, it would add a major level of complexity to the iron phosphate stabilization process. (c) It is too early in the development program to determine which stabilizer will produce the minimum amount of stabilized waste form for the entire HLW inventory, but the volume is assumed to be within the range of 12,250 to 14,470 m3. (d) The stacked vessel height of the hot process vessels in the hydroceramic grout process (i.e., 21 m) appears to be about the same as that estimated by the Direct Cementitious Waste Process in 1998, for which a conceptual design was developed. Some of the conceptual design efforts in the 1998 study may be applicable to the stabilizer processes addressed in this EDF. (e) The gamma radiation fields near the process vessels handling HLW calcine would vary from a range of about 300-350 R/hr at a distance of 2.5 cm from the side of the vessels to a range of about 50-170 R/hr at a distance of 100 cm from the side of the vessels. The calculations were made for combined calcine, which was defined as the total HLW calcine inventory uniformly mixed. (f) The gamma radiation fields near the stabilized waste in canisters would range from about 25-170 R/hr at 2.5 cm from the side of the canister and 5-35 R/hr at 100 cm from the side of the canister, depending on the which bin set was the source of calcine.

T. R. Thomas; A. K. Herbst

2005-06-01

127

Molecular processes affecting the macroscopic tribological behavior of surfaces  

International Nuclear Information System (INIS)

The purpose of this study was to investigate the influence of various additives on the tribological properties of a system in the macro and nanoscale, as well as clarify lubricant interactions with surfaces and materials. To accomplish that a wide range of lubricants and additives were considered. Moreover, a detail chemical analysis was carried out, in order to explain the effect on the friction coefficient, wear mechanisms and corrosion process in lubricated tribosystems. This research was mainly focused on additives for water based lubricants. Solutions of anti-corrosion and anti-foaming agents - amines, friction modifiers - glycols and amines derivatives with longer hydrocarbon chains were investigated. The results showed that the additives build chemisorbed mono-molecular films on surfaces, what was verified by AFM, AR-XPS and AES analysis, and compared with SESSA simulation. Investigated tribo-films affect the friction coefficient in nanoscale, however during tribological test in the macroscale, they showed different results depending on contact situation (rolling and/or sliding). The conclusion states that the differences in tribological behavior might be due to the orientation of amine and hydroxyl groups on the surfaces. Furthermore, lubricants for rolling bearing elements such as polar and non polar oils with zinc dialkyldithiophosphate (ZDDP) additives were studied. The results demonstrated that a reaction layer formation is strongly dependent on the molecumation is strongly dependent on the molecular polarity of the oils and additives. The evolution of the topography and mechanical properties of the ZDDP-derived tribo-layer with rubbing time showed that initially a thin and soft ZDDP reaction layer develops very quick. The second part of this work was addressed on chemical vapor deposited (CVD) diamond films and transition metal dichalcogenides (TMD) in consideration of desired properties for micro electro mechanical systems (MEMS). The main scientific goal of this part of the work was to evaluate the influence of surface morphologies on the micro- and nanomechanical properties. Keeping nanotribological application in mind, a comparative AFM analysis were carried out and the influence of carbon content on the mechanical behaviour of such a coatings was evaluated. (author)

128

Using Static and Dynamic Visuals to Represent Chemical Change at Molecular Level  

Science.gov (United States)

The study examines the effectiveness of visually enhanced instruction that emphasizes molecular representations. Instructional conditions were specified in terms of the visual elaboration level (static and dynamic) and the presentation mode (whole class and individual). Fifty-two eighth graders (age range 14-15 years) participated in one of the…

Ardac, Dilek; Akaygun, Sevil

2005-01-01

129

Tree-indexed processes: a high level crossing analysis  

OpenAIRE

Consider a branching diffusion process on R1 starting at the origin. Take a high level u>0 and count the number R(u,n) of branches reaching u by generation n. Let Fk,n(u) be the probability P(R(u,n)

Mark Kelbert; Yuri Suhov

2003-01-01

130

Coupled processes in NRC high-level waste research  

International Nuclear Information System (INIS)

The author discusses NRC research effort in support of evaluating license applications for disposal of nuclear waste and for promulgating regulations and issuing guidance documents on nuclear waste management. In order to do this they fund research activities at a number of laboratories, academic institutions, and commercial organizations. One of our research efforts is the coupled processes study. This paper discusses interest in coupled processes and describes the target areas of research efforts over the next few years. The specific research activities relate to the performance objectives of NRC's high-level waste (HLW) regulation and the U.S. Environmental Protection Agency (EPA) HLW standard. The general objective of the research program is to ensure the NRC has a sufficient independent technical base to make sound regulatory decisions

131

Decontamination of low-level process effluents by reverse osmosis  

International Nuclear Information System (INIS)

A new facility is under construction at the Savannah River Plant to decontaminate process effluents containing low levels of radionuclides and hazardous chemicals prior to discharge to a surface stream. The facility is called the F/H Effluent Treatment Facility (F/H ETF). The effluentes are composed primarily of evaporator condensates which are currently discharged to seepage basins. The new facility will allow closure of the basins in order to meet the provisions of the Resource Conservation and Recovery Act. The 50 million dollar facility will contain advanced water treatment systems representative of the best currently available technology. The paper paper describes the facility and summarizes bench and pilot scale process development work that has been used to establish the design bases for the facility

132

[Level investigation on coptidis rhizoma processing methods and product specifications].  

Science.gov (United States)

The existing processing methods, commercial specification and grades, and the marketing of Coptidis Rhizoma were systematical researched, referring to ancient, modern and contemporary medical literatures with the combination of our fieldwork on main origins of Coptidis Rhizoma and some herbs markets. Results showed that Coptidis Rhizoma processing methods mainly included sun-dried method and baked method anciently. For now, the processing methods become various, including thin paper-covering under the sun drying, direct drying, oven drying and microflame-fry drying. In the literatures, the main chemical constituent berberine was determined of its content to analyze the processing methods, finding that the sun drying and baked drying affect the berberine content, so the temperature must be controlled when drying. The thin paper-covering drying method is so cumbersome for large quantities of medicinal herbs and in wind conditions that it has been eliminated. Eventually, direct drying, oven drying and microflame-fry drying are chosen to the large-scale socialized production for their convenient and simple operation, making up the current main processing methods. Coptidis Rhizoma products have 3 specifications of Weilian, Yalian, Yunlian, of each specification there are 2 levels, but in fact the market of Weilian commodities overtakes the Yunlian, which only sold in parts of Yunnan, and the no-sale Yalian. The mainstream commercial Weilian are often sold in general way, gradeless and uniformly-priced. There are regional differences of the processing methods on Coptidis Rhizoma, which needs unified research and development of relevant standard operating procedures to ensure the quality of medicine, urgently. Coptidis Rhizoma product specifications and the intrinsic quality-grade correlation need to be further improved, which could provide a more reliable standard for quality at competitive prices, and it is recommended that "medicinal commercial specification and grade standard" content be increased into the Herbs part of Chinese Pharmacopoeia. PMID:25509292

Huang, He; Liu, Xin; Huang, Lu-Qi; Yang, Yan-Fang; Wu, He-Zhen

2014-08-01

133

Tuning molecular level alignment and work function modification through self-assembled monolayers on noble metals: theoretical perspectives  

International Nuclear Information System (INIS)

Full text: There is currently significant interest in highly-ordered, self-assembled monolayers (SAMs) on (noble) metal surfaces, inspired both by the emergence of the field of molecular electronics alongside the high potential for SAMs to improve the properties of more conventional device structures. SAMs are also used to control surface reactivity and for chemical sensing applications. In order to tune the interface properties and to endow the self-assembled systems with functionality suitable for use in either macroscopic or nanoscale devices, the use of ?-conjugated systems is highly promising and the focus of intense, multidisciplinary research. The goal of the present study is to provide an in-depth description of the electronic structure of the interface between metallic substrates and covalently bound conjugated molecules. In this way, we expect to devise strategies to tune the interaction and thus the properties of the investigated systems and eventually to gain a full understanding of the processes governing the electronics of metal/organic interfaces. Here, we describe a first step in that direction: we study conjugated SAMs consisting of molecules with widely varied molecular ionization potentials, different conjugated backbones with different polarizabilities, and monolayers with varying degrees of coverage. We consider noble metals with varying work functions such as Au, Ag, and Pt, different molecule docking groups and investigate the effects of mechanups and investigate the effects of mechanical stress on the organic system. Using DFT band-structure-type methods, the details of the interface morphology, charge transfer between the metal and the molecules, interface dipoles, molecular layer depolarization, and work function modifications as well as the alignment between metallic and molecular levels are described. Our thorough analysis provides results that are sometimes a priori unexpected, like the finding that by properly tuning the molecular structure, the level alignment between the metal and the organic monolayer can be fully decoupled from the work-function modification induced by the SAM. (author)

134

Polyelectrolytes processing at pilot scale level by electron beam irradiation  

International Nuclear Information System (INIS)

Three years of research, combined with engineering activities, have culminated in the development of a new method of electron beam processing applicable up to the pilot scale level, namely, the polyelectrolytes (acrylamide - acrylic acid copolymers) electron beam processing. This new radiation processing method has been achieved by bilateral co-operation between the National Institute for Laser, Plasma and Radiation Physics (NILPRP) and the Electrical Design and Research Institute, EDRI - Bucharest. The polyelectrolytes electron beam (EB) processing was put in operation at EDRI, where, recently, an industrial electron accelerator of 2 MeV and 20 kW, manufactured by Institute of Nuclear Physics, Novosibirsk, Russia was installed in a specially designed irradiation facility. Automatic start-up via computer control makes it compatible with industrial processing. According to the first conclusions, which resulted from our experimental research with regard to acrylamide - acrylic acid copolymers production by EB irradiation, the proper physical and chemical characteristics can be well controlled by chemical composition to be treated and by suitable adjustment of absorbed dose and absorbed dose rate. So, it was possible to obtain a very large area of characteristics and therefore a large area of applications. The conversion coefficient is very high (> 98%) and concentration of the residual monomer is under 0.05%. The tests applied to some wastewaters from the vegetable oil o some wastewaters from the vegetable oil plants demonstrated that the fatty substances, matters in suspension, chemical oxygen demand and biological oxygen demand over 5 days were much reduced, in comparison with classical treatment. Also, sedimentation time was around four times smaller and sediment volume was 60% smaller than the values obtained in case of classical treatment. The necessary EB absorbed dose for the acrylamide - acrylic acid aqueous solution polymerization, established by optimization of chemical composition and irradiation conditions, is rather small, of about 1 kGy, that makes the use of electron beam processing very economically attractive in this type of application. Thus, if all auxiliary systems are made and suitable adapted, the estimation of processing rate is 3600 kg/h. The acrylamide - acrylic acid copolymers are used in the range of 4 to 8 g per 1 m3 of wastewater. A vegetable oil plant which processes 100 000 ton/year of sunflower produces about 1 260 000 m3/year wastewater. The necessary amount of polyelectrolytes is 315-630 kg/year. This value can by ensured by our technology in a very short time, from 315 s to 630 s. (authors)

135

Kinetics of chemical degradation in monoclonal antibodies: relationship between rates at the molecular and peptide levels.  

Science.gov (United States)

This article describes a method to analyze the kinetics of monoclonal antibody degradation and to determine the quantitative relationship between the degradation rates observed at the molecular and peptide levels. The proposed model can be applied to any degradation pathway that can be well approximated by a first order reaction; if several pathways exist, the model assumes that they are independent. Three examples are presented to illustrate the benefits of this approach. For each case, the calculated fractions of species were compared to one or more data sets to demonstrate the good agreement between experimental results and model prediction. This method can serve as a valuable tool in interpreting chromatograms of degraded samples and predicting the population of species present at the molecular level when only data from degradation observed at the peptide level is available. This method further demonstrates how deviations from predictions of simple models can be used to unravel additional, unforeseen reactions. PMID:20302349

Ionescu, Roxana; Vlasak, Josef

2010-04-15

136

Identification of mycobacteria in peat moss processing plants : application of molecular biology approaches  

Energy Technology Data Exchange (ETDEWEB)

Health concerns regarding environmental mycobacteria has led to the development of exposure assessment methods for the evaluation of certain workplaces where the presence of these agents is suspected. Hypersensitivity pneumonitis (HP) has been described in peat moss workers who are regularly exposed to significant levels of bioaerosols in peat moss processing plants. Although mycobacteria have been cultured from peat moss, plant workers exposure to mycobacterial bioaerosols has never been studied. This article presented the results of a study that evaluated the presence of mycobacteria in air samples from peat moss processing plants using molecular biology approaches (cloning-sequencing and polymerase chain reaction (PCR)) and the workers exposure using immunoglobin G (IgG) complexes to mycobacteria. It also compared species detected in air samples and in peat moss. Two peat moss processing plants were chosen among 14 previously studied and a total of 49 clones were sequenced. Real-time PCR was also performed on the same air samples to evaluate the airborne concentration of mycobacteria and estimate exposure levels. The article discussed the materials and methods used in the study, the results of the study, and subsequent discussion of the results. It was concluded that peat moss processing plants workers are exposed to mycobacteria in addition to other biological agents. It was suggested that further studies are needed to confirm the specificity of the mycobacterial IgG. 34 refs., 2 tabs., 1 fig.

Cayer, M.P.; Veillette, M.; Pageau, P.; Cormier, Y.; Duchaine, C.; Meriaux, A. [Laval Univ., Quebec City, PQ (Canada). Inst. Universitaire de pneumologie et de cardiologie; Veillette, M.; Meriaux, A.; Cormier, Y. [Laval Univ., Quebec City, PQ (Canada). Dept. of Biology and Microbiology; Hamelin, R.; Bergeron, M.J. [Natural Resources Canada, Sainte-Foy, PQ (Canada). Canadian Forest Service

2007-01-15

137

Subfemtosecond pulse generation in a three-level system by molecular modulation  

International Nuclear Information System (INIS)

We show that subfemtosecond pulse train with large pulse spacing can be generated by using three correlated Raman generators between three Raman levels with strong molecular modulation to control the generation and propagation of the cascade stimulated Raman sidebands. For three Raman generators based on the fundamental rotational and vibrational Raman transitions (v=0,J=0?v=0,J=2?v=1,J=0?v=0,J=0) in molecular hydrogen, a train of subfemtosecond pulses with a pulse spacing of 379.9 fs and pulse width down to 0.26 fs can be generated

138

Empoderamiento: Proceso, Nivel y Contexto / Empowerment: Process, Level, and Context  

Scientific Electronic Library Online (English)

Full Text Available En este artículo se discute el fenómeno del empoderamiento y se analiza la distinción teórica entre proceso y resultado de empoderamiento (Zimmerman, 2000). A partir de las formulaciones de este autor y el aporte de una perspectiva interaccional (Bronfenbrenner, 1987), se sostiene que aquella difere [...] nciación es poco viable en términos objetivos y absolutos o de esencia, pero sí útil, en términos analíticos, desde la percepción de la propia comunidad involucrada, que debe ser comprendida por el colaborador externo. También se propone establecer una diferencia entre contexto y nivel de empoderamiento, y analizar el contexto del fenómeno en los niveles individual, organizacional y comunitario del agregado social, lo que aporta claridad a su definición. De esta manera adquiere centralidad la concepción del empoderamiento como proceso en sucesivos contextos que benefician no sólo a los individuos sino que a los colectivos sociales Abstract in english A critical analysis of the concept of empowerment and the theoretical distinction between empowerment process and outcome (Zimmerman, 2000) are presented. Based on Zimmerman's conceptualisation, and the interaccional perspective (Bronfenbrenner, 1987), we argue that the distinction between empowerme [...] nt process and outcome, though analytically useful (if based on the perception of the community itself from their own experience, which must be understood by professional agent) is not always viable in absolute or objective terms. In addition, we suggest to distinguish between context and level of analyses in empowerment theory, and to analyze the context of the empowerment phenomenon at the individual, organizational and community level, which clarifies the definition of each of them. In sum, empowerment is conceived as a process within successive contexts that benefits not only individuals, but also different social aggregate kinds of groups

Carmen, Silva; María Loreto, Martínez.

2004-11-01

139

Levels of feature analysis in processing visual patterns.  

Science.gov (United States)

In this paper, a revised Pandemonium-like model of visual-feature processing is formulated and a preliminary test of its feasibility is reported. The model differentiates visual-feature processing into a series of hierarchical stages organized by increasing complexity, with the output of each stage going both to the next higher stage, and directly to a more central processor. In the experiment, subjects sorted decks of cards into piles according to the presence or absence of a target stimulus which differed from nontargets in a variety of different features; detection of a feature was sufficient for detection of a target. The data generally supported the revised Pandemonium model, in that targets which differed from nontargets in features thought to be low in the hierarchy were processed faster than targets whose difference was in a high level feature. An extension of the revised model did somewhat less well in predicting the results of sorting for targets in which detection of any one of several features was sufficient for target detection. PMID:1005018

Ward, L M; Wexler, D A

1976-01-01

140

HELAC-PHEGAS: A generator for all parton level processes  

Science.gov (United States)

The updated version of the HELAC-PHEGAS event generator is presented. The matrix elements are calculated through Dyson-Schwinger recursive equations using color connection representation. Phase-space generation is based on a multichannel approach, including optimization. HELAC-PHEGAS generates parton level events with all necessary information, in the most recent Les Houches Accord format, for the study of any process within the Standard Model in hadron and lepton colliders. New version program summaryProgram title: HELAC-PHEGAS Catalogue identifier: ADMS_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADMS_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 35 986 No. of bytes in distributed program, including test data, etc.: 380 214 Distribution format: tar.gz Programming language: Fortran Computer: All Operating system: Linux Classification: 11.1, 11.2 External routines: Optionally Les Houches Accord (LHA) PDF Interface library ( http://projects.hepforge.org/lhapdf/) Catalogue identifier of previous version: ADMS_v1_0 Journal reference of previous version: Comput. Phys. Comm. 132 (2000) 306 Does the new version supersede the previous version?: Yes, partly Nature of problem: One of the most striking features of final states in current and future colliders is the large number of events with several jets. Being able to predict their features is essential. To achieve this, the calculations need to describe as accurately as possible the full matrix elements for the underlying hard processes. Even at leading order, perturbation theory based on Feynman graphs runs into computational problems, since the number of graphs contributing to the amplitude grows as n!. Solution method: Recursive algorithms based on Dyson-Schwinger equations have been developed recently in order to overcome the computational obstacles. The calculation of the amplitude, using Dyson-Schwinger recursive equations, results in a computational cost growing asymptotically as 3 n, where n is the number of particles involved in the process. Off-shell subamplitudes are introduced, for which a recursion relation has been obtained allowing to express an n-particle amplitude in terms of subamplitudes, with 1-, 2-, … up to (n-1) particles. The color connection representation is used in order to treat amplitudes involving colored particles. In the present version HELAC-PHEGAS can be used to efficiently obtain helicity amplitudes, total cross sections, parton-level event samples in LHA format, for arbitrary multiparticle processes in the Standard Model in leptonic, pp¯ and pp collisions. Reasons for new version: Substantial improvements, major functionality upgrade. Summary of revisions: Color connection representation, efficient integration over PDF via the PARNI algorithm, interface to LHAPDF, parton level events generated in the most recent LHA format, k reweighting for Parton Shower matching, numerical predictions for amplitudes for arbitrary processes for phase-space points provided by the user, new user interface and the possibility to run over computer clusters. Running time: Depending on the process studied. Usually from seconds to hours. References:A. Kanaki, C.G. Papadopoulos, Comput. Phys. Comm. 132 (2000) 306. C.G. Papadopoulos, Comput. Phys. Comm. 137 (2001) 247. URL: http://www.cern.ch/helac-phegas.

Cafarella, Alessandro; Papadopoulos, Costas G.; Worek, Malgorzata

2009-10-01

141

Molecular-Level Insights into Photocatalysis from Scanning Probe Microscopy Studies on TiO2(110)  

Energy Technology Data Exchange (ETDEWEB)

The field of heterogeneous photocatalysis has grown considerably in the decades since Fujishima and Honda's ground-breaking publications of photoelectrochemistry on TiO2. Numerous review articles continue to point to both progress made in the use of heterogeneous materials (such as TiO2) to perform photoconversion processes, and the many opportunities and challenges in heterogeneous photocatalysis research such as solar energy conversion and environmental remediation. The past decade has also seen an increase in the use of molecular-level approaches applied to model single crystal surfaces in an effort to obtain new insights into photocatalytic phenomena. In particular, scanning probe techniques (SPM) have enabled researchers to take a ‘nanoscale’ approach to photocatalysis that includes interrogation of the reactivities of specific sites and adsorbates on a model photocatalyst surface. The rutile TiO2(110) surface has become the prototypical oxide single crystal surface for fundamental studies of many interfacial phenomena. In particular, TiO2(110) has become an excellent model surface for probing photochemical and photocatalytic reactions at the molecular level. A variety of experimental approaches have emerged as being ideally suited for studying photochemical reactions on TiO2(110), including desorption-oriented approaches and electronic spectroscopies, but perhaps the most promising techniques for evaluating site-specific properties are those of SPM. In this review, we highlight the growing use of SPM techniques in providing molecular-level insights into surface photochemistry on the model photocatalyst surface of rutile TiO2(110). Our objective is to both illustrate the unique knowledge that scanning probe techniques have already provided the field of photocatalysis, and also to motivate a new generation of effort into the use of such approaches to obtain new insights into the molecular level details of photochemical events occurring at interfaces. Discussion will start with an examination of how scanning probe techniques are being used to characterize the TiO2(110) surface in ways that are relevant to photocatalysis. We will then discuss specific classes of photochemical reaction on TiO2(110) for which SPM has proven indispensible in providing unique molecular-level insights, and conclude with discussion of future areas in which SPM studies may prove valuable to photocatalysis on TiO2. This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. I.L. was partially supported by a Pacific Northwest National Laboratory (PNNL) Chemical Imaging Initiative project. PNNL is a multiprogram national laboratory operated for DOE by Battelle.

Henderson, Michael A.; Lyubinetsky, Igor

2013-06-12

142

Bias-dependent molecular-level structure of electrical double layer in ionic liquid on graphite  

Energy Technology Data Exchange (ETDEWEB)

Bias-dependent structure of electrochemical double layers at liquid-solid interfaces underpin a multitude of phenomena in virtually all areas of scientific enquiry ranging from energy storage and conversion systems, biology, to geophysics and geochemistry. Here we report the bias-evolution of the electric double layer structure of an ionic liquid on highly ordered pyrolytic graphite as a model system for carbon-based electrodes for electrochemical supercapacitors measured by atomic force microscopy. Matching the observed structures to molecular dynamics simulations allows us to resolve steric effects due to cation and anion layers. We observe reconfiguration under applied bias and the orientational transitions in the Stern layer. The synergy between molecular dynamics simulation and experiment provides a comprehensive picture of structural phenomena and long- and short range interactions. This insight will improve understanding of the mechanism of charge storage in electrochemical capacitors on a molecular level which can be used to enhance their electrochemical performance.

Black, Jennifer M [ORNL; Walters, Deron [Asylum Research, Santa Barbara, CA; Labuda, Aleksander [Asylum Research, Santa Barbara, CA; Feng, Guang [ORNL; Hillesheim, Patrick C [ORNL; Dai, Sheng [ORNL; Cummings, Peter T [ORNL; Kalinin, Sergei V [ORNL; Proksch, Roger [Asylum Research, Santa Barbara, CA; Balke, Nina [ORNL

2013-01-01

143

An algebraic approach for simultaneous solution of process and molecular design problems  

Scientific Electronic Library Online (English)

Full Text Available The property integration framework has allowed for simultaneous representation of processes and products from a properties perspective and thereby established a link between molecular and process design problems. The simultaneous approach involves solving two reverse problems. The first reverse prob [...] lem identifies the property targets corresponding to the desired process performance. The second reverse problem is the reverse of a property prediction problem, which identifies the molecular structures that match the targets identified in the first problem. Group Contribution Methods (GCM) are used to form molecular property operators that will be used to track properties. Earlier contributions in this area have worked to include higher order estimation of GCM for solving the molecular design problem. In this work, the accuracy of the property prediction is further enhanced by improving the techniques to enumerate higher order groups. Incorporation of these higher order enumeration techniques increases the efficiency of property prediction and thus the application range of the group contribution methods in molecular design problems. Successful tracking of properties is the key in applying the reverse problem formulation for integrated process and product design problems. An algebraic technique has been developed for solving process and molecular design problems simultaneously. Since both process and molecular property operators target the same optimum process performance, the set of inequality expressions can be solved simultaneously to identify the molecules that meet the desired process performance. Since this approach is based on an algebraic algorithm, any number of properties can be tracked simultaneously.

S., Bommareddy; N. G., Chemmangattuvalappil; C. C., Solvason; M. R., Eden.

2010-09-01

144

Tectonic processes modelling for high-level radioactive waste disposal  

International Nuclear Information System (INIS)

The possibility of using deep geological formations to dispose of high-level radioactive waste (HLW) is a subject raising heated debate among scientists. In Russia, the idea of constructing HLW repository in the Niznekansky granitoid massif (NKM) in Krasnoyarsk area is widely discussed. To solve this problem we are elaborating a technology associated with time – space stability prediction of the geological environment, which is subject to geodynamic processes evolutionary effects. It is based on the prediction of isolation properties stability in a structural tectonic block of the Earth’s crust for a given time. The danger is in the possibility that the selected structural block may be broken by new tectonic faults or movements on a passive fault may be activated and thus underground water may penetrate to HLW containers

145

Conceptual process for conversion of high level waste to glass  

International Nuclear Information System (INIS)

During a ten-year period highly radioactive wastes amounting to 22 million gallons of salt cake and 5 million gallons of wet sludge are to be converted to 1.2 million gallons of glass and 24 million gallons of decontaminated salt cake and placed in the new storage facilities which will provide high assurance of containment with minimal reliance on maintenance and surveillance. The glass will contain nearly all of the radioactivity in a form that is highly resistant to leaching and dispersion. The salt cake will contain a small amount of residual radioactivity. The process is shown in Figure 1 and the facilities may be arranged in seven modules to accomplish seven tasks, (1) remove wastes from tanks, (2) separate sludge and salt, (3) decontaminate salt, (4) solidify and package sludge and 137Cs, (5) solidify and package decontaminated salt, (6) store high level waste, and (7) store decontaminated salt cake

146

Molecular cytogenetics in an assessment of DNA damage and repair processes  

International Nuclear Information System (INIS)

Mutagenesis is one of the simplest and most effective methods for inducing plant variability. The mechanisms, which evoke variability, are chromosomal aberrations, arising from DNA double strand breaks (DSB). The frequency of chromosomal aberrations is correlated with the level of DNA damage and effectivity of cell repair system. Chromosomal aberrations can be detected using simple cytogenetic methods, however to assess the direct DNA damage and the effectivity of repair processes during recovery time after mutagenic treatment. in nucleus molecular methods are required. Comet assay and TUNEL test were successfully adapted and accepted for the detection of DNA fragmentation in mutagenesis. TUNEL test, based on labelling the 3'OH ends of DNA with fluorochrome - conjugated dUTP by terminal deoxynucleotidyl transferase (TdT) allows to distinguish the nuclei with DNA fragmentation. Another method - comet assay, based on the migration of damaged DNA fragments in electric field and forming an image similar to comet, is used for analysis of the level of DNA damage in single nucleus. Fluorescent in situ hybridization (FISH), provides new tools for the identification of individual chromosomes/chromosome arms participating in formation of the aberration. An advantage of FISH is possibility to understand the composition of the micronuclei thus improving an existing micronucleus test. An application of region-specific DNA probes (telomere and centromere) as well as rDNA as probes and centromere) as well as rDNA as probes enables the analysis of the break points in the chromosomes leading to micronuclei. The application of the molecular cytogenetic methods will be presented as the analysis of the level of DNA damage and effectivity of repair processes in Hordeum vulgare cells (2n=14) after mutagenic treatment with ?-rays, MH, and MNU in different postincubation times. FISH with rDNA and centromeric/telomeric DNA as probes, to evaluate chromosome aberrations in barley cells caused by these mutagens will show the differences between action of these mutagens. (author)

147

Pseudomonas viridiflava, a multi host plant pathogen with significant genetic variation at the molecular level.  

Science.gov (United States)

The pectinolytic species Pseudomonas viridiflava has a wide host range among plants, causing foliar and stem necrotic lesions and basal stem and root rots. However, little is known about the molecular evolution of this species. In this study we investigated the intraspecies genetic variation of P. viridiflava amongst local (Cretan), as well as international isolates of the pathogen. The genetic and phenotypic variability were investigated by molecular fingerprinting (rep-PCR) and partial sequencing of three housekeeping genes (gyrB, rpoD and rpoB), and by biochemical and pathogenicity profiling. The biochemical tests and pathogenicity profiling did not reveal any variability among the isolates studied. However, the molecular fingerprinting patterns and housekeeping gene sequences clearly differentiated them. In a broader phylogenetic comparison of housekeeping gene sequences deposited in GenBank, significant genetic variability at the molecular level was found between isolates of P. viridiflava originated from different host species as well as among isolates from the same host. Our results provide a basis for more comprehensive understanding of the biology, sources and shifts in genetic diversity and evolution of P. viridiflava populations and should support the development of molecular identification tools and epidemiological studies in diseases caused by this species. PMID:22558343

Sarris, Panagiotis F; Trantas, Emmanouil A; Mpalantinaki, Evaggelia; Ververidis, Filippos; Goumas, Dimitrios E

2012-01-01

148

Decontamination processes for low level radioactive waste metal objects  

International Nuclear Information System (INIS)

Disposal and safe storage of contaminated nuclear waste is a problem of international scope. Although the greatest volume of such waste is concentrated in the USA and former Soviet Union, Western Europe and Japan have contaminated nuclear waste requiring attention. Japan's radioactive nuclear waste is principally generated at nuclear power plants since it has no nuclear weapons production. However, their waste reduction, storage and disposal problems may be comparable to that of the USA on an inhabited area basis when consideration is given to population density where Japan's population, half that of the USA, lives in an area slightly smaller than that of California's. If everyone's backyard was in California, the USA might have insoluble radioactive waste reduction, storage and disposal problems. Viewing Japan's contaminated nuclear waste as a national problem requiring solutions, as well as an economic opportunity, Morikawa began research and development for decontaminating low level radioactive nuclear waste seven years ago. As engineers and manufacturers of special machinery for many years Morikawa brings special electro/mechanical/pneumatic Skills and knowledge to solving these unique problems. Genden Engineering Services and Construction Company (GESC), an affiliate of Japan Atomic Power Company, recently joined with Morikawa in this R ampersand D effort to decontaminate low level radioactive nuclear waste (LLW) and to substantially reduce the volume of such nucubstantially reduce the volume of such nuclear waste requiring long term storage. This paper will present equipment with both mechanical and chemical processes developed over these several years by Morikawa and most recently in cooperation with GESC

149

Experimental study on intermediate level radioactive waste processing  

International Nuclear Information System (INIS)

In the disposal of intermediate level radioactive wastes, multilayer package will be adopted. The multilayer package consists of cement-solidified waste and a container such as a drum - can with concrete liner or a concrete container. So, on the waste to be cement-solidified in such container, experimental study was carried out as follows. (1) Cement-solidification method. (2) Mechanical behaviour of cement-solidified waste. The mechanical behaviour of the containers was studied by the finite element method and experiment, and the function of pressure-balancing valves was also studied. The following data on processing intermediate level radioactive wastes were obtained. (1) In the case of cement-solidified waste, the data to select the suitable solidifying material and the standard mixing proportion were determined. (2) The basic data concerning the uniaxial compressive strength of cement-solidified waste, the mechanical behaviour of cement-solidified waste packed in a drum under high hydrostatic pressure, the shock response of cement-solidified waste at the time of falling and so on were obtained. (3) The pressure-balancing valves worked at about 0.5 Kg/cm2 pressure difference inside and outside a container, and the deformation of a drum cover was 10 to 13 mm. In case of the pressure difference less than 0,5 Kg/cm2, the valves shut, and water flow did occur. (auth.)

150

Predicting the residual aluminum level in water treatment process  

Directory of Open Access Journals (Sweden)

Full Text Available In water treatment processes, aluminum salts are widely used as coagulation chemical. High dose of aluminum has been proved to be at least a minor health risk and some evidence points out that aluminum could increase the risk of Alzheimer's disease thus it is important to minimize the amount of residual aluminum in drinking water and water used at food industry. In this study, the data of a water treatment plant (WTP was analyzed and the residual aluminum in drinking water was predicted using Multiple Linear Regression (MLR and Artificial Neural Network (ANN models. The purpose was to find out which variables affect the amount of residual aluminum and create simple and reliable prediction models which can be used in an early warning system (EWS. Accuracy of ANN and MLR models were compared. The new nonlinear scaling method based on generalized norms and skewness was used to scale all measurement variables to range [?2...+2] before data-analysis and modeling. The effect of data pre-processing was studied by comparing prediction results to ones achieved in an earlier study. Results showed that it is possible to predict the baseline level of residual aluminum in drinking water with a simple model. Variables that affected the most the amount of residual aluminum were among others: raw water temperature, raw water KMnO4 and PAC / KMnO4-ratio. The accuracies of MLR and ANN models were found to be almost equal. Study also showed that data pre-processing affects to the final prediction result.

J. Tomperi

2012-06-01

151

Imaging and tuning molecular levels at the surface of a gated graphene device.  

Science.gov (United States)

Gate-controlled tuning of the charge carrier density in graphene devices provides new opportunities to control the behavior of molecular adsorbates. We have used scanning tunneling microscopy (STM) and spectroscopy (STS) to show how the vibronic electronic levels of 1,3,5-tris(2,2-dicyanovinyl)benzene molecules adsorbed onto a graphene/BN/SiO2 device can be tuned via application of a backgate voltage. The molecules are observed to electronically decouple from the graphene layer, giving rise to well-resolved vibronic states in dI/dV spectroscopy at the single-molecule level. Density functional theory (DFT) and many-body spectral function calculations show that these states arise from molecular orbitals coupled strongly to carbon-hydrogen rocking modes. Application of a back-gate voltage allows switching between different electronic states of the molecules for fixed sample bias. PMID:24746016

Riss, Alexander; Wickenburg, Sebastian; Tan, Liang Z; Tsai, Hsin-Zon; Kim, Youngkyou; Lu, Jiong; Bradley, Aaron J; Ugeda, Miguel M; Meaker, Kacey L; Watanabe, Kenji; Taniguchi, Takashi; Zettl, Alex; Fischer, Felix R; Louie, Steven G; Crommie, Michael F

2014-06-24

152

Sequential Remediation Processes for a Low Level Pesticide Wastewater  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was to develop a remediation system for the treatment of a low-level pesticide wastewater that uses available onfarm organic matter as an absorption media, is capable of reducing the concentration of the pesticide to a safe level and is economically viable for implementation by farmers. The absorption capacity of chopped hay and soybean to the fungicide captan was evaluated under batch conditions and the effectiveness of the composting process in depredating captan in contaminated organic materials was evaluated. The results showed that both hay and soybean plant residues were very effective in absorbing 99.2% and 98.5% of captan form the wastewater after 4 hours, respectively. Because of its availability, hay can be used in an onfarm pesticide immobilization system that consists of shallow reinforced concrete pit (filled with hay with steel bars across the top for machinery to roll onto and be washed. The wastewater can be retained for 24 hours which is a sufficient time for hay to absorb the captan. The contaminated hay can then be composted. The addition of used cooking oil raised the temperature of the composting mixture to 63?C. Small reductions in moisture content (from 60% to 58.9 % and C:N ratio (from 30:1 to 28:1 were observed while reductions of 18.92%, 15.56% and 4.8% in the volatile solids, total carbon total Kjeldahl nitrogen were achieved after 10 d of composting, respectively. About 92.4% of the captan was degraded in the first 4 days of composting. Most of captan (92.4% was degraded during the mesophilic stage (first 3 days. The degradation rate constant for the mesophilic stage (0.724 d-1 was 2.74 times the degradation rate constant for the thermophilic stage (0.264 d-1. An onfarm windrow composting process would be very effective in degrading captan contaminated hay. The captan contaminated hay could be mixed with equal amount poultry manure or dairy manure to provide the required bioavailable carbon and nutrients for the composting process. Some used cooking oil could also be added to maintain higher temperature within the compost matrix. The windrows should be mixed on a daily basis to provide sufficient oxygen for the composting microorganisms.

Abdel E. Ghaly

2012-02-01

153

Molecular electronic level alignment at weakly coupled organic film/metal interfaces.  

Science.gov (United States)

Electronic level alignment at interfaces of molecular materials with inorganic semiconductors and metals controls many interfacial phenomena. How the intrinsic properties of the interacting systems define the electronic structure of their interface remains one of the most important problems in molecular electronics and nanotechnology that can be solved through a combination of surface science experimental techniques and theoretical modeling. In this article, we address this fundamental problem through experimental and computational studies of molecular electronic level alignment of thin films of C(6)F(6) on noble metal surfaces. The unoccupied electronic structure of C(6)F(6) is characterized with single molecule resolution using low-temperature scanning tunneling microscopy-based constant-current distance-voltage spectroscopy. The experiments are performed on several noble metal surfaces with different work functions and distinct surface-normal projected band structures. In parallel, the electronic structures of the quantum wells (QWs) formed by the lowest unoccupied molecular orbital state of the C(6)F(6) monolayer and multilayer films and their alignment with respect to the vacuum level of the metallic substrates are calculated by solving the Schrödinger equation for a semiempirical one-dimensional (1D) potential of the combined system using input from density functional theory. Our analysis shows that the level alignment for C(6)F(6) molecules bound through weak van der Waals interactions to noble metal surfaces is primarily defined by the image potential of metal, the electron affinity of the molecule, and the molecule surface distance. We expect the same factors to determine the interfacial electronic structure for a broad range of molecule/metal interfaces. PMID:25303040

Zhao, Jin; Feng, Min; Dougherty, Daniel Barker; Sun, Hao; Petek, Hrvoje

2014-10-28

154

Molecular phylogeny of extant equids and effects of ancestral polymorphism in resolving species-level phylogenies.  

Science.gov (United States)

Short divergence times and processes such as incomplete lineage sorting and species hybridization are known to hinder the inference of species-level phylogenies due to the lack of sufficient informative genetic variation or the presence of shared but incongruent polymorphism among taxa. Extant equids (horses, zebras, and asses) are an example of a recently evolved group of mammals with an unresolved phylogeny, despite a large number of molecular studies. Previous surveys have proposed trees with rather poorly supported nodes, and the bias caused by genetic introgression or ancestral polymorphism has not been assessed. Here we studied the phylogenetic relationships of all extant species of Equidae by analyzing 22 partial mitochondrial and nuclear genes using maximum likelihood and Bayesian inferences that account for heterogeneous gene histories. We also examined genetic signatures of lineage sorting and/or genetic introgression in zebras by evaluating patterns of intraspecific genetic variation. Our study improved the resolution and support of the Equus phylogeny and in particular the controversial positions of the African wild ass (E. asinus) and mountain zebra (E. zebra): the African wild ass is placed as a sister species of the Asiatic asses and the mountain zebra as the sister taxon of Grevy's and Burchell's zebras. A shared polymorphism (indel) detected among zebra species in the Estrogen receptor 1 gene was likely due to incomplete lineage sorting and not genetic introgression as also indicated by other mitochondrial (Cytochrome b) and nuclear (Y chromosome and microsatellites) markers. Ancestral polymorphism in equids might have contributed to the long-standing lack of clarity in the phylogeny of this highly threatened group of mammals. PMID:22846684

Steiner, Cynthia C; Mitelberg, Anna; Tursi, Rosanna; Ryder, Oliver A

2012-11-01

155

Atmospheric processes on ice nanoparticles in molecular beams.  

Czech Academy of Sciences Publication Activity Database

Ro?. 2, ?. 2014 (2014), s. 4. ISSN 2296-2646 R&D Projects: GA ?R GA203/09/0422; GA ?R GAP208/11/0161 Institutional support: RVO:61388955 Keywords : molecular beams * photodissociation * water clusters Subject RIV: BL - Plasma and Gas Discharge Physics

Fárník, Michal; Poterya, Viktoriya

2014-01-01

156

The Defense Waste Processing Facility: an innovative process for high-level waste immobilization  

International Nuclear Information System (INIS)

The Defense Waste Processing Facility (DWPF), under construction at the Department of Energy's Savannah River Plant (SRP), will process defense high-level radioactive waste so that it can be disposed of safely. The DWPF will immobilize the high activity fraction of the waste in borosilicate glass cast in stainless steel canisters which can be handled, stored, transported and disposed of in a geologic repository. The low-activity fraction of the waste, which represents about 90% of the high-level waste HLW volume, will be decontaminated and disposed of on the SRP site. After decontamination the canister will be welded shut by an upset resistance welding technique. In this process a slightly oversized plug is pressed into the canister opening. At the same time a large current is passed through the canister and plug. The higher resistance of the canister/plug interface causes the heat which welds the plug in place. This process provides a high quality, reliable weld by a process easily operated remotely

157

Directional solvent for membrane-free water desalination-A molecular level study  

OpenAIRE

Development of desalination technologies has been identified as vital to fulfilling future water demand. In this paper, we use molecular simulation to demonstrate that decanoic acid can dissolve water but reject salt, and itself is insoluble in water. We have recently demonstrated that the directional properties of decanoic acid together with the temperature dependence of water solubility in decanoic acid can be utilized to design a desalination process which extracts water molecules, using t...

Luo, Tengfei; Bajpayee, Anurag; Chen, Gang

2011-01-01

158

Quantifying the atomic-level mechanics of single long physisorbed molecular chains  

OpenAIRE

Mechanical properties of biopolymers such as DNA and proteins have been studied to understand the details of complex processes in living systems via systematic statistical analyses of repeated measurements. However, the mechanical behavior of a single molecular chain pulled off a surface has never been investigated with atomic-scale resolution. Herein, we present such a study on in situ polymerized fluorene chains by pulling individual chains with the tip of an atomic force microscope at 4.8 ...

Kawai, Shigeki; Koch, Matthias; Gnecco, Enrico; Sadeghi, Ali; Pawlak, Re?my; Glatzel, Thilo; Schwarz, Jutta; Goedecker, Stefan; Hecht, Stefan; Baratoff, Alexis; Grill, Leonhard; Meyer, Ernst

2014-01-01

159

The principle of coherence in multi-level brain information processing.  

Science.gov (United States)

Synchronisation has become one of the major scientific tools to explain biological order at many levels of organisation. In systems neuroscience, synchronised subthreshold and suprathreshold oscillatory neuronal activity within and between distributed neuronal assemblies is acknowledged as a fundamental mode of neuronal information processing. Coherent neuronal oscillations correlate with all basic cognitive functions, mediate local and long-range neuronal communication and affect synaptic plasticity. However, it remains unclear how the very fast and complex changes of functional neuronal connectivity necessary for cognition, as mediated by dynamic patterns of neuronal synchrony, could be explained exclusively based on the well-established synaptic mechanisms. A growing body of research indicates that the intraneuronal matrix, composed of cytoskeletal elements and their binding proteins, structurally and functionally connects the synapses within a neuron, modulates neurotransmission and memory consolidation, and is hypothesised to be involved in signal integration via electric signalling due to its charged surface. Theoretical modelling, as well as emerging experimental evidence indicate that neuronal cytoskeleton supports highly cooperative energy transport and information processing based on molecular coherence. We suggest that long-range coherent dynamics within the intra- and extracellular filamentous matrices could establish dynamic ordered states, capable of rapid modulations of functional neuronal connectivity via their interactions with neuronal membranes and synapses. Coherence may thus represent a common denominator of neurophysiological and biophysical approaches to brain information processing, operating at multiple levels of neuronal organisation, from which cognition may emerge as its cardinal manifestation. PMID:22986048

Plankar, Matej; Brežan, Simon; Jerman, Igor

2013-01-01

160

Elevated levels of high-molecular-weight adiponectin in type 1 diabetes  

DEFF Research Database (Denmark)

BACKGROUND: Several studies have shown that type 1 diabetic patients have elevated total levels of the adipocyte-derived adipocytokine adiponectin. However, adiponectin circulates in three different subforms, and the high-molecular-weight (HMW) subform is believed to be the primary biologically active form. The effects of the medium-molecular-weight (MMW) subform and the low-molecular-weight (LMW) subform are still unresolved. PURPOSE: The objective of the study was to investigate the distribution of the three molecular subforms of adiponectin in well-characterized groups of type 1 diabetics with varying degrees of nephropathy as well as in healthy control subjects. STUDY POPULATION: Two hundred seven individuals were included: 58 type 1 diabetics with normoalbuminuria, 46 with microalbuminuria, 46 with macroalbuminuria, and 57 matched controls. METHODS: The HMW, MMW, and LMW subforms were measured using a validated in-house time-resolved immunoflourometric assay after separation by fast protein liquid chromatography. RESULTS: The absolute concentrations of total adiponectin and all subforms were higher in type 1 diabetic patients than healthy controls. However, the relative HMW fraction was up-regulated in type 1 diabetes (P < 0.001), whereas the MMW (P < 0.001) and LMW fractions (P < 0.05) were down-regulated, compared with controls. Accordingly, the increase in concentration of total adiponectin was primarily caused by a major increase of the HMW subform. Levels of total adiponectin and the HMW subform (absolute and relative) were generally unaffected by nephropathy status defined by urinary albumin excretion rate. CONCLUSION: Type 1 diabetes per se is associated with higher adiponectin levels than healthy subjects. This increase is mainly explained by an elevation in the HMW subform. The elevation is unaffected by gender and diabetic kidney disease Udgivelsesdato: 2008/8

Leth, H.; Andersen, K.K.

2008-01-01

161

Hanford low-level waste process chemistry testing data package  

International Nuclear Information System (INIS)

Recently, the Tri-Party Agreement (TPA) among the State of Washington Department of Ecology, U.S. Department of Energy (DOE) and the US Environmental Protection Agency (EPA) for the cleanup of the Hanford Site was renegotiated. The revised agreement specifies vitrification as the encapsulation technology for low level waste (LLW). A demonstration, testing, and evaluation program underway at Westinghouse Hanford Company to identify the best overall melter-system technology available for vitrification of Hanford Site LLW to meet the TPA milestones. Phase I is a open-quotes proof of principleclose quotes test to demonstrate that a melter system can process a simulated highly alkaline, high nitrate/nitrite content aqueous LLW feed into a glass product of consistent quality. Seven melter vendors were selected for the Phase I evaluation: joule-heated melters from GTS Duratek, Incorporated (GDI); Envitco, Incorporated (EVI); Penberthy Electomelt, Incorporated (PEI); and Vectra Technologies, Incorporated (VTI); a gas-fired cyclone burner from Babcock ampersand Wilcox (BCW); a plasma torch-fired, cupola furnace from Westinghouse Science and Technology Center (WSTC); and an electric arc furnace with top-entering vertical carbon electrodes from the U.S. Bureau of Mines (USBM)

162

Molecular Mass Characterization of Glycosaminoglycans with Different Degrees of Sulfation in Bioengineered Heparin Process by Size Exclusion Chromatography.  

Science.gov (United States)

Different degrees of glycosaminoglycan sulfation result in their different charge densities. The charge density differences impact their migration behavior in polyacrylamide gel electrophoresis and size exclusion chromatography, two of the most common methods for determining relative molecular masses of polysaccharides. In this study, we investigated the feasibility of using commercially available heparin oligosaccharides as calibrants for measuring the relative molecular masses of intermediates in a bioengineered heparin process that have different levels of sulfation. A size exclusion chromatography method was established that eliminates this charge density effect and allows the determination of relative molecular mass using a single calibration curve with heparin oligosaccharides calibrants. This is accomplished by overcoming the electrostatic interaction between the glycosaminoglycans and size exclusion chromatography stationary phase using high ionic strength mobile phase. PMID:23258975

Wang, Zhenyu; Zhang, Fuming; Dordick, Jonathan S; Linhardt, Robert J

2012-10-01

163

Tank farm processing of high-level waste for the Defense Waste Processing Facility  

International Nuclear Information System (INIS)

The high-level radioactive waste that has accumulated at the Savannah River Plant is stored in large, underground steel tanks. Programs to remove the waste from the storage tanks and immobilize the radioactivity in borosilicate glass in the Defense Waste Processing Facility (DWPF) are currently in the construction phase. Much of the processing of the waste prior to vitrification is accomplished in the waste storage areas (tank farms). Tank farm processing includes resuspension and washing of the insoluble (sludge) waste, dissolution and decontamination of soluble (salt) waste, and waste transfer between the tanks and operations areas. The overall program for handling the waste in the tank farms, the research program that supports it, and the major concerns with implementing the program are described

164

Influence of polyvinylpyrrolidone with different molecular weight on silver nanoconfiguration in polyol process  

International Nuclear Information System (INIS)

This paper researches the influence of different molecular weight polyvinylpyrrolidone on silver nanoconfiguration in polyol process. The silver nanoparticles are characterized by scanning electron microscopy and X-ray diffraction. Their optical properties are studied by UV-Vis spectrophotometer. The results indicate that under of silver nanoparticles different morphology will be made by different molecular weight polyvinylpyrrolidone under the same experimental conditions; the yield of silver nanowires is the largest when the molecular weight of polyvinylpyrrolidone is 1.0 x 104, and silver nanowires will reduce and silver nanocubes will increase when the molecular weight of polyvinylpyrrolidone increases. (authors)

165

Effects of subchronic exposure to glyphosate in juvenile oysters (Crassostrea gigas): From molecular to individual levels.  

Science.gov (United States)

Glyphosate-based herbicides are extensively used and can be measured in aquatic ecosystems, including coastal waters. The effect of glyphosate on non-target organisms is an issue of worldwide concern. The aim of this study was to investigate the effects of subchronic exposure to glyphosate in juvenile oysters, Crassostrea gigas. Yearling oysters were exposed to three concentrations of glyphosate (0.1, 1 and 100?gL(-1)) for 56days. Various endpoints were studied, from the individual level (e.g., gametogenesis and tissue alterations) to the molecular level (mRNA quantification), including biochemical endpoints such as glutathione-S-transferase (GST) and catalase activities and malondialdehyde content. No mortality and growth occurred during the experiment, and individual biomarkers revealed only slight effects. The levels of gene expression significantly increased in oysters exposed to the highest glyphosate concentration (GST and metallothioneins) or to all concentrations (multi-xenobiotic resistance). These results suggested an activation of defence mechanisms at the molecular level. PMID:25455786

Mottier, Antoine; Séguin, Alexis; Devos, Alexandre; Pabic, Charles Le; Voiseux, Claire; Lebel, Jean Marc; Serpentini, Antoine; Fievet, Bruno; Costil, Katherine

2014-10-30

166

A probe to study the toxic interaction of tartrazine with bovine hemoglobin at the molecular level.  

Science.gov (United States)

Tartrazine is an artificial azo dye commonly used in food products, but tartrazine in the environment is potentially harmful. The toxic interaction between tartrazine and bovine hemoglobin (BHb) was investigated using fluorescence, synchronous fluorescence, UV-vis absorption, circular dichroism (CD) and molecular modeling techniques under simulated physiological conditions. The fluorescence data showed that tartrazine can bind with BHb to form a complex. The binding process was a spontaneous molecular interaction, in which van der Waals' forces and hydrogen bonds played major roles. Molecular docking results showed that the hydrogen bonds exist between the oxygen atoms at position 31 of tartrazine and the nitrogen atom NZ7 on Lys99, and also between the oxygen atoms at position 15 of tartrazine and the nitrogen atom NZ7 on Lys104, Lys105. The results of UV-vis and CD spectra revealed that tartrazine led to conformational changes in BHb, including loosening of the skeleton structure and decreasing ? helix in the secondary structure. The synchronous fluorescence experiment revealed that tartrazine binds into the hemoglobin central cavity, and this was verified using a molecular modeling study. PMID:23653408

Li, Yating; Wei, Haoran; Liu, Rutao

2014-03-01

167

Work of adhesion between mucin macromolecule and calcium-alginate gels on molecular level.  

Science.gov (United States)

The bioadhesion of biopolymers to mucus layers is of great interest for the development of drug delivery systems. Herein we use AFM force measurements to evaluate the interaction on molecular level between a mucin macromolecule attached to an AFM tip and a calcium-alginate gel layer. The total work of adhesion is measured from the AFM force curves depending on different parameters: time of contact, G/M ratio of the alginate, and crosslink ratio of the gel. The total work of adhesion is found to be in the range of 1×10(-19) to 6×10(-18)J. The results show that the work of adhesion increases with the time of contact but it is independent from the molecular mass of the alginate, the G/M ratio of the alginate and crosslink ratio of the gel. PMID:25843845

Popeski-Dimovski, Riste

2015-06-01

168

CEA Atalante: High level process shielded line and high level analysis shielded line  

International Nuclear Information System (INIS)

This is a PowerPoint presentation of Atalante, Atelier Alpha et Laboratoires pour Analyses, Transuraniens, the CEA's nuclear facility for scientific research of the nuclear fuel cycle in its downstream part. High level process and analysis shielded lines of Atalante are installed at CEA/Marcoule. Atalante facility presentation is given: - Short dated studies context with HA effluents; - Test demonstration; - Main equipment. The general characteristics of the process shielded cells are presented. Steps in highly active and long-lived radioactive waste processing are mentioned and identification of three R and D directions are given: (1) Research on solutions allowing the separation and transmutation of long-lived nuclides; (2) Study of the possibilities of reversible or irreversible disposal in deep geological formations; (3) Study of methods of packaging and of surface interim storage. CEA's role is underlined: - bring elements for evaluation (annual evaluation of researches); - studies on long-lived radionuclides separation for transmutation (or specific conditioning) in the frame of the 1991 French law concerning the reduction of the harmfulness of waste; performances to reach, namely, recovery yields of Am and Cm greater than 99.9% (lanthanides < 5 %). In progress are studies concerning the development of hydrometallurgical processes for the separation obtained in 2001. This step allowed to valid the choice of the extracting system. The reference processes are: DIAg system. The reference processes are: DIAMEX for both extraction of trivalent actinides and lanthanides, SANEX for trivalent actinides separation from lanthanides, Am / Cm separation with Diamides as extracting molecules. Technical feasibility to be demonstrated implies tests to be performed at a representative scale. Previous tests before starting the CBP are mentioned: - Tele-demonstrability; - Unit tests; - 1. global test; - Biological shielding closing and ultimate infrastructure checking. Analysis shielded cell (CBA) are described and main techniques presented: - ICP/AES Function; - FP and actinides from solutions. Principle of fuel dissolution, extraction runs, FP concentrations, hulls and fines dissolutions are described. In excitation by plasma of the atoms contained in the liquid sample, for detection of the emitted photonic radiation during the relaxation process of both excited ions and atoms the following techniques are used: - High Pressure Chromatography in liquid phase CBA; - X hybrid (K edge); - U and Pu determinations in both aqueous and organic phases; - by absorption (for uranium) and by fluorescence (X fluorescence from K rays) for U and Pu; - U determination by absorption. In case of U and Pu determination by fluorescence the photon spectra of K rays X fluorescence is monitored by a high purity germanium detector. The fluorescence peaks areas of uranium (Ka2) and plutonium (Ka1) are compared to a calibration carried out in the same operating conditions. In case of FXL function applied for both uranium and plutonium traces determination, contained in organic and aqueous solutions from spent fuels reprocessing, the principle is presented. The sample is introduced in the measurement cell. The solution to be analysed is excited by photon produced in a X tube conducting to electrons arrangement with X photon emission which energy is characteristic of the element. Photons dues to the X fluorescence (L ray) are collected by a high purity germanium detector after a graphite Bragg reflector

169

An Investigation of Bacterial Protein Interactions as a Primary Research Project in a Sophomore-Level Molecular Biology Course  

Directory of Open Access Journals (Sweden)

Full Text Available Longer term research activities that may be incorporated in undergraduate courses are a powerful tool for promoting student interest and learning, developing cognitive process skills, and allowing undergraduates to experience real research activities in which they may not otherwise have the opportunity to participate. The challenge to doing so in lower-level courses is that students may have not fully grasped the scientific concepts needed to undertake such research endeavors, and that they may be discouraged if activities are perceived to be too challenging. The paper describes how a bacterial protein:protein interaction detection system was adapted and incorporated into the laboratory component of a sophomore-level Molecular Cell Biology course. The project was designed to address multiple learning objectives connecting course content to the laboratory activities, as well as teach basic molecular biology laboratory skills and procedures in the context of a primary research activity. Pre- and posttesting and student surveys both suggest that the laboratory curriculum resulted in significant learning gains, as well as being well received and valued by the students.?

Jean A. Cardinale

2011-09-01

170

Ellipticity dependence of plateau structures in atomic and molecular processes in a strong laser field  

International Nuclear Information System (INIS)

In this paper, we present a quantum-mechanical theory in order to describe laser-induced and laser-assisted atomic and molecular processes with an emphasis on an elliptically polarized strong laser field. The features of the high-energy regions of spectra and their cutoffs are analyzed in detail for different values of ellipticity, laser intensities and various atomic and molecular species. Our theoretical study is focused on the ellipticity dependence of the plateau structures that appear in the energy spectra of atomic and molecular processes in strong laser fields. (paper)

171

Reconsolidation and extinction are dissociable and mutually exclusive processes: behavioral and molecular evidence.  

Science.gov (United States)

Memory persistence is critically influenced by retrieval. In rats, a single presentation of a conditioned fear stimulus induces memory reconsolidation and fear memory persistence, while repeated fear cue presentations result in loss of fear through extinction. These two opposite behavioral outcomes are operationally linked by the number of cue presentations at memory retrieval. However, the behavioral properties and mechanistic determinants of the transition have not yet been explored; in particular, whether reconsolidation and extinction processes coexist or are mutually exclusive, depending on the exposure to non-reinforced retrieval events. We characterized both behaviorally and molecularly the transition from reconsolidation to extinction of conditioned fear and showed that an increase in calcineurin (CaN) in the basolateral amygdala (BLA) supports the shift from fear maintenance to fear inhibition. Gradually increasing the extent of retrieval induces a gradual decrease in freezing responses to the conditioned stimulus and a gradual increase in amygdala CaN level. This newly synthesized CaN is required for the extinction, but not the reconsolidation, of conditioned fear. During the transition from reconsolidation to extinction, we have revealed an insensitive state of the fear memory where NMDA-type glutamate receptor agonist and antagonist drugs are unable either to modulate CaN levels in the BLA or alter the reconsolidation or extinction processes. Together, our data indicate both that reconsolidation and extinction are mutually exclusive processes and also reveal the presence of a transitional, or "limbo," state of the original memory between these two alternative outcomes of fear memory retrieval, when neither process is engaged. PMID:24523532

Merlo, Emiliano; Milton, Amy L; Goozée, Zara Y; Theobald, David E; Everitt, Barry J

2014-02-12

172

The defense waste processing facility: the final processing step for defense high-level waste disposal  

International Nuclear Information System (INIS)

The policy of the U.S. Department of Energy is to pursue an aggressive and credible waste management program that advocates final disposal of government generated (defense) high-level nuclear wastes in a manner consistent with environmental, health, and safety responsibilities and requirements. The Defense Waste Processing Facility (DWPF) is an essential component of the Department's program. It is the first project undertaken in the United States to immobilize government generated high-level nuclear wastes for geologic disposal. The DWPF will be built at the Department's Savannah River Plant near Aiken, South Carolina. When construction is complete in 1989, the DWPF will begin processing the high-level waste at the Savannah River Plant into a borosilicate glass form, a highly insoluble and non-dispersable product, in easily handled canisters. The immobilized waste will be stored on site followed by transportation to and disposal in a Federal repository. The focus of this paper is on the DWPF. The paper discusses issues which justify the project, summarizes its technical attributes, analyzes relevant environmental and insitutional factors, describes the management approach followed in transforming technical and other concepts into concrete and steel, and concludes with observations about the future role of the facility

173

78 FR 18481 - Project-Level Predecisional Administrative Review Process  

Science.gov (United States)

...For instance, mining, cattle grazing...administrative review process for proposed actions...also true of other automated and even hand stamping...officer to assure that automated systems used as part of the objection process are...

2013-03-27

174

High-precision frequency measurements: indispensable tools at the core of the molecular-level analysis of complex systems  

OpenAIRE

This perspective article provides an assessment of the state-of-the-art in the molecular-resolution analysis of complex organic materials. These materials can be divided into biomolecules in complex mixtures (which are amenable to successful separation into unambiguously defined molecular fractions) and complex nonrepetitive materials (which cannot be purified in the conventional sense because they are even more intricate). Molecular-level analyses of these complex systems critically depend o...

Hertkorn, N.; Ruecker, C.; Meringer, M.; Gugisch, R.; Frommberger, M.; Perdue, E. M.; Witt, M.; Schmitt-kopplin, P.

2007-01-01

175

Molecular-level methods for monitoring soil organic matter responses to global climate change.  

Science.gov (United States)

Soil organic matter (SOM) is one of the most complex natural mixtures on earth. It plays a critical role in many ecosystem functions and is directly responsible for sustaining life on our planet. However, due to its chemical heterogeneity, SOM composition at molecular-level is still not completely clear. Consequently, the response of SOM to global climate change is difficult to predict. Here we highlight applications of two complementary molecular-level methods (biomarkers and nuclear magnetic resonance (NMR)) for ascertaining SOM responses to various environmental changes. Biomarker methods that measure highly specific molecules determine the source and decomposition stage of SOM components. However, biomarkers only make up a small fraction of SOM components because much of SOM is non-extractable. By comparison, (13)C solid-state NMR allows measurement of SOM in its entirety with little or no pretreatment but suffers from poor resolution (due to overlapping of SOM components) and insensitivity, and thus subtle changes in SOM composition may not always be detected. Alternatively, (1)H solution-state NMR methods offer an added benefit of improved resolution and sensitivity but can only analyze SOM components that are fully soluble (humic type molecules) in an NMR compatible solvent. We discuss how these complementary methods have been employed to monitor SOM responses to: soil warming in a temperate forest, elevated atmospheric CO(2) and nitrogen fertilization in a temperate forest, and permafrost thawing in the Canadian High Arctic. These molecular-level methods allow some novel and important observations of soil dynamics and ecosystem function in a changing climate. PMID:21416081

Feng, Xiaojuan; Simpson, Myrna J

2011-05-01

176

Ultrafast molecular processes mapped by femtosecond x-ray diffraction  

Science.gov (United States)

X-ray diffraction with a femtosecond time resolution allows for mapping photoinduced structural dynamics on the length scale of a chemical bond and in the time domain of atomic and molecular motion. In a pump-probe approach, a femtosecond excitation pulse induces structural changes which are probed by diffracting a femtosecond hard x-ray pulse from the excited sample. The transient angular positions and intensities of diffraction peaks give insight into the momentary atomic or molecular positions and into the distribution of electronic charge density. The simultaneous measurement of changes on different diffraction peaks is essential for determining atom positions and charge density maps with high accuracy. Recent progress in the generation of ultrashort hard x-ray pulses (Cu K?, wavelength ?=0.154 nm) in laser-driven plasma sources has led to the implementation of the powder diffraction and the rotating crystal method with a time resolution of 100 fs. In this contribution, we report new results from powder diffraction studies of molecular materials. A first series of experiments gives evidence of a so far unknown concerted transfer of electrons and protons in ammonium sulfate [(NH4)2SO4], a centrosymmetric structure. Charge transfer from the sulfate groups results in the sub-100 fs generation of a confined electron channel along the c-axis of the unit cell which is stabilized by transferring protons from the adjacent ammonium groups into the channel. Time-dependent charge density maps display a periodic modulation of the channel's charge density by low-frequency lattice motions with a concerted electron and proton motion between the channel and the initial proton binding site. A second study addresses atomic rearrangements and charge dislocations in the non-centrosymmetric potassium dihydrogen phosphate [KH2PO4, KDP]. Photoexcitation generates coherent low-frequency motions along the LO and TO phonon coordinates, leaving the average atomic positions unchanged. The time-dependent maps of electron density demonstrate a concomitant oscillatory relocation of electronic charge with a spatial amplitude of the order of a chemical bond length, two orders of magnitude larger than the vibrational amplitudes. The coherent phonon motions drive the charge relocation, similar to a soft mode driven phase transition between the ferro- and paraelectric phase of KDP.

Elsaesser, Thomas

2012-02-01

177

Protein Molecular Structures, Protein SubFractions, and Protein Availability Affected by Heat Processing: A Review  

Directory of Open Access Journals (Sweden)

Full Text Available The utilization and availability of protein depended on the types of protein and their specific susceptibility to enzymatic hydrolysis (inhibitory activities in the gastrointestine and was highly associated with protein molecular structures. Studying internal protein structure and protein subfraction profiles leaded to an understanding of the components that make up a whole protein. An understanding of the molecular structure of the whole protein was often vital to understanding its digestive behavior and nutritive value in animals. In this review, recently obtained information on protein molecular structural effects of heat processing was reviewed, in relation to protein characteristics affecting digestive behavior and nutrient utilization and availability. The emphasis of this review was on (1 using the newly advanced synchrotron technology (S-FTIR as a novel approach to reveal protein molecular chemistry affected by heat processing within intact plant tissues; (2 revealing the effects of heat processing on the profile changes of protein subfractions associated with digestive behaviors and kinetics manipulated by heat processing; (3 prediction of the changes of protein availability and supply after heat processing, using the advanced DVE/OEB and NRC-2001 models, and (4 obtaining information on optimal processing conditions of protein as intestinal protein source to achieve target values for potential high net absorbable protein in the small intestine. The information described in this article may give better insight in the mechanisms involved and the intrinsic protein molecular structural changes occurring upon processing.

Peiqiang Yu

2007-01-01

178

Protein Molecular Structures, Protein SubFractions, and Protein Availability Affected by Heat Processing: A Review  

International Nuclear Information System (INIS)

The utilization and availability of protein depended on the types of protein and their specific susceptibility to enzymatic hydrolysis (inhibitory activities) in the gastrointestine and was highly associated with protein molecular structures. Studying internal protein structure and protein subfraction profiles leaded to an understanding of the components that make up a whole protein. An understanding of the molecular structure of the whole protein was often vital to understanding its digestive behavior and nutritive value in animals. In this review, recently obtained information on protein molecular structural effects of heat processing was reviewed, in relation to protein characteristics affecting digestive behavior and nutrient utilization and availability. The emphasis of this review was on (1) using the newly advanced synchrotron technology (S-FTIR) as a novel approach to reveal protein molecular chemistry affected by heat processing within intact plant tissues; (2) revealing the effects of heat processing on the profile changes of protein subfractions associated with digestive behaviors and kinetics manipulated by heat processing; (3) prediction of the changes of protein availability and supply after heat processing, using the advanced DVE/OEB and NRC-2001 models, and (4) obtaining information on optimal processing conditions of protein as intestinal protein source to achieve target values for potential high net absorbable protein in the small intestine. The infoe protein in the small intestine. The information described in this article may give better insight in the mechanisms involved and the intrinsic protein molecular structural changes occurring upon processing.

179

Molecular level studies on binding modes of labeling molecules with polyalanine peptides  

Science.gov (United States)

In this work, the binding modes of typical labeling molecules (thioflavin T (ThT), Congo red (CR) and copper(ii) phthalocyanine tetrasulfonic acid tetrasodium salt (PcCu(SO3Na)4)) on pentaalanine, which is a model peptide segment of amyloid peptides, have been resolved at the molecular level by using scanning tunneling microscopy (STM). In the STM images, ThT molecules are predominantly adsorbed parallel to the peptide strands and two binding modes could be identified. It was found that ThT molecules are preferentially binding on top of the peptide strand, and the mode of intercalated between neighboring peptides also exists. The parallel binding mode of CR molecules can be observed with pentaalanine peptides. Besides the binding modes of labeling molecules, the CR and PcCu(SO3Na)4 display different adsorption affinity with the pentaalanine peptides. The results could be beneficial for obtaining molecular level insight of the interactions between labeling molecules and peptides.In this work, the binding modes of typical labeling molecules (thioflavin T (ThT), Congo red (CR) and copper(ii) phthalocyanine tetrasulfonic acid tetrasodium salt (PcCu(SO3Na)4)) on pentaalanine, which is a model peptide segment of amyloid peptides, have been resolved at the molecular level by using scanning tunneling microscopy (STM). In the STM images, ThT molecules are predominantly adsorbed parallel to the peptide strands and two binding modes could be identified. It was found that ThT molecules are preferentially binding on top of the peptide strand, and the mode of intercalated between neighboring peptides also exists. The parallel binding mode of CR molecules can be observed with pentaalanine peptides. Besides the binding modes of labeling molecules, the CR and PcCu(SO3Na)4 display different adsorption affinity with the pentaalanine peptides. The results could be beneficial for obtaining molecular level insight of the interactions between labeling molecules and peptides. Electronic supplementary information (ESI) available. See DOI: 10.1039/c0nr00782j

Mao, Xiaobo; Wang, Chenxuan; Ma, Xiaojing; Zhang, Min; Liu, Lei; Zhang, Lan; Niu, Lin; Zeng, Qindao; Yang, Yanlian; Wang, Chen

2011-04-01

180

Identification and analysis of evolutionary selection pressures acting at the molecular level in five forkhead subfamilies  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Members of the forkhead gene family act as transcription regulators in biological processes including development and metabolism. The evolution of forkhead genes has not been widely examined and selection pressures at the molecular level influencing subfamily evolution and differentiation have not been explored. Here, in silico methods were used to examine selection pressures acting on the coding sequence of five multi-species FOX protein subfamily clusters; FoxA, FoxD, FoxI, FoxO and FoxP. Results Application of site models, which estimate overall selection pressures on individual codons throughout the phylogeny, showed that the amino acid changes observed were either neutral or under negative selection. Branch-site models, which allow estimated selection pressures along specified lineages to vary as compared to the remaining phylogeny, identified positive selection along branches leading to the FoxA3 and Protostomia clades in the FoxA cluster and the branch leading to the FoxO3 clade in the FoxO cluster. Residues that may differentiate paralogs were identified in the FoxA and FoxO clusters and residues that differentiate orthologs were identified in the FoxA cluster. Neutral amino acid changes were identified in the forkhead domain of the FoxA, FoxD and FoxP clusters while positive selection was identified in the forkhead domain of the Protostomia lineage of the FoxA cluster. A series of residues under strong negative selection adjacent to the N- and C-termini of the forkhead domain were identified in all clusters analyzed suggesting a new method for refinement of domain boundaries. Extrapolation of domains among cluster members in conjunction with selection pressure information allowed prediction of residue function in the FoxA, FoxO and FoxP clusters and exclusion of known domain function in residues of the FoxA and FoxI clusters. Conclusion Consideration of selection pressures observed in conjunction with known functional information allowed prediction of residue function and refinement of domain boundaries. Identification of residues that differentiate orthologs and paralogs provided insight into the development and functional consequences of paralogs and forkhead subfamily composition differences among species. Overall we found that after gene duplication of forkhead family members, rapid differentiation and subsequent fixation of amino acid changes through negative selection has occurred.

Rannala Bruce

2008-09-01

181

Understanding the Relative Contributions of Lower-Level Word Processes, Higher-Level Processes, and Working Memory to Reading Comprehension Performance in Proficient Adult Readers  

Science.gov (United States)

Although a considerable amount of evidence has been amassed regarding the contributions of lower-level word processes, higher-level processes, and working memory to reading comprehension, little is known about the relationships among these sources of individual differences or their relative contributions to reading comprehension performance. This…

Hannon, Brenda

2012-01-01

182

Levels of processing and language modality specificity in working memory  

OpenAIRE

Neural networks underpinning working memory demonstrate sign language specific components possibly related to differences in temporary storage mechanisms. A processing approach to memory systems suggests that the organisation of memory storage is related to type of memory processing as well. In the present study, we investigated for the first time semantic, phonological and orthographic processing in working memory for sign- and speech-based language. During fMRI we administered a picture-bas...

Rudner, Mary; Karlsson, Thomas; Gunnarsson, Johan; Ro?nnberg, Jerker

2013-01-01

183

Level structure and production cross section of ?12 Be studied with coupled-channels antisymmetrized molecular dynamics  

International Nuclear Information System (INIS)

A theoretical framework of coupled-channels antisymmetrized molecular dynamics that describes the multistrangeness system with mixing between different baryon species is developed and applied to ?12C and ?12Be. By introducing a minor modification to the YN G-matrix interaction derived from the Nijmegen model-D, the low-lying level structure and production cross section of ?12C are reasonably described. It is found that the low-lying states of ?12Be are dominated by the 11B x ?- channel and their order strongly depends on ?N effective interactions used in the calculation. The calculated peak position of the production cross section depends on the ?N effective interaction and the magnitude of spin-flip and non-spin-flip cross sections of K-p?K+?- elemental processes. We suggest that the 12C(K-,K+)?12Be reaction possibly provides us information about the ?N interaction.

184

Recent progress in atomic and molecular processes in plasma  

International Nuclear Information System (INIS)

In the recent works, atomic processes in Debye plasmas are investigated by a series of methods including the classical, semi-classical and quantum-mechanical ones. It's found that due to the plasma screening of the interactions both the binding energies and the number of bound states are reduced, while the radial extension of the wave functions become broader. Taking into account these plasma screening effects on the atomic structure and interactions, we have studied the photo processes, electron-impact processes and heavy particle collisions in a wide range of plasma screening conditions. Our work demonstrates that the screening effects are very important in Debye plasmas, which should be taken into account in the modeling and diagnostics of these plasmas. (author)

185

Rovibrational coupling in molecular nitrogen at high temperature: An atomic-level study  

Energy Technology Data Exchange (ETDEWEB)

This article contains an atomic-level numerical investigation of rovibrational relaxation in molecular nitrogen at high temperature (>4000 K), neglecting dissociation. We conduct our study with the use of pure Molecular Dynamics (MD) and Classical Trajectory Calculations (CTC) Direct Simulation Monte Carlo (DSMC), verified to produce statistically identical results at the conditions of interest here. MD and CTC DSMC solely rely on the specification of a potential energy surface: in this work, the site-site Ling-Rigby potential. Additionally, dissociation is prevented by modeling the N–N bond either as a harmonic or an anharmonic spring. The selected molecular model was shown to (i) recover the shear viscosity (obtained from equilibrium pure MD Green-Kubo calculations) of molecular nitrogen over a wide range of temperatures, up to dissociation; (ii) predict well the near-equilibrium rotational relaxation behavior of N{sub 2}; (iii) reproduce vibrational relaxation times in excellent accordance with the Millikan-White correlation and previous semi-classical trajectory calculations in the low temperature range, i.e., between 4000 K and 10?000 K. By simulating isothermal relaxations in a periodic box, we found that the traditional two-temperature model assumptions become invalid at high temperatures (>10?000 K), due to a significant coupling between rotational and vibrational modes for bound states. This led us to add a modification to both the Jeans and the Landau-Teller equations to include a coupling term, essentially described by an additional relaxation time for internal energy equilibration. The degree of anharmonicity of the N{sub 2} bond determines the strength of the rovibrational coupling. Although neglecting N{sub 2} dissociation only provides a partial description of a nitrogen system at very high temperatures, high-energy trends for bound-bound transitions are essential to understand nonequilibrium gas flows, with possible implications on rovibration/chemistry interaction at the onset of N{sub 2} dissociation.

Valentini, Paolo, E-mail: vale0142@umn.edu; Norman, Paul, E-mail: norma198@umn.edu; Zhang, Chonglin, E-mail: zhang993@umn.edu; Schwartzentruber, Thomas E., E-mail: schwart@aem.umn.edu [Department of Aerospace Engineering and Mechanics, College of Science and Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

2014-05-15

186

Rovibrational coupling in molecular nitrogen at high temperature: An atomic-level study  

International Nuclear Information System (INIS)

This article contains an atomic-level numerical investigation of rovibrational relaxation in molecular nitrogen at high temperature (>4000 K), neglecting dissociation. We conduct our study with the use of pure Molecular Dynamics (MD) and Classical Trajectory Calculations (CTC) Direct Simulation Monte Carlo (DSMC), verified to produce statistically identical results at the conditions of interest here. MD and CTC DSMC solely rely on the specification of a potential energy surface: in this work, the site-site Ling-Rigby potential. Additionally, dissociation is prevented by modeling the N–N bond either as a harmonic or an anharmonic spring. The selected molecular model was shown to (i) recover the shear viscosity (obtained from equilibrium pure MD Green-Kubo calculations) of molecular nitrogen over a wide range of temperatures, up to dissociation; (ii) predict well the near-equilibrium rotational relaxation behavior of N2; (iii) reproduce vibrational relaxation times in excellent accordance with the Millikan-White correlation and previous semi-classical trajectory calculations in the low temperature range, i.e., between 4000 K and 10?000 K. By simulating isothermal relaxations in a periodic box, we found that the traditional two-temperature model assumptions become invalid at high temperatures (>10?000 K), due to a significant coupling between rotational and vibrational modes for bound states. This led us to add a modification to both the Jeans and the Landau-Teller equations to include a coupling term, essentially described by an additional relaxation time for internal energy equilibration. The degree of anharmonicity of the N2 bond determines the strength of the rovibrational coupling. Although neglecting N2 dissociation only provides a partial description of a nitrogen system at very high temperatures, high-energy trends for bound-bound transitions are essential to understand nonequilibrium gas flows, with possible implications on rovibration/chemistry interaction at the onset of N2 dissociation

187

Rovibrational coupling in molecular nitrogen at high temperature: An atomic-level study  

Science.gov (United States)

This article contains an atomic-level numerical investigation of rovibrational relaxation in molecular nitrogen at high temperature (>4000 K), neglecting dissociation. We conduct our study with the use of pure Molecular Dynamics (MD) and Classical Trajectory Calculations (CTC) Direct Simulation Monte Carlo (DSMC), verified to produce statistically identical results at the conditions of interest here. MD and CTC DSMC solely rely on the specification of a potential energy surface: in this work, the site-site Ling-Rigby potential. Additionally, dissociation is prevented by modeling the N-N bond either as a harmonic or an anharmonic spring. The selected molecular model was shown to (i) recover the shear viscosity (obtained from equilibrium pure MD Green-Kubo calculations) of molecular nitrogen over a wide range of temperatures, up to dissociation; (ii) predict well the near-equilibrium rotational relaxation behavior of N2; (iii) reproduce vibrational relaxation times in excellent accordance with the Millikan-White correlation and previous semi-classical trajectory calculations in the low temperature range, i.e., between 4000 K and 10 000 K. By simulating isothermal relaxations in a periodic box, we found that the traditional two-temperature model assumptions become invalid at high temperatures (>10 000 K), due to a significant coupling between rotational and vibrational modes for bound states. This led us to add a modification to both the Jeans and the Landau-Teller equations to include a coupling term, essentially described by an additional relaxation time for internal energy equilibration. The degree of anharmonicity of the N2 bond determines the strength of the rovibrational coupling. Although neglecting N2 dissociation only provides a partial description of a nitrogen system at very high temperatures, high-energy trends for bound-bound transitions are essential to understand nonequilibrium gas flows, with possible implications on rovibration/chemistry interaction at the onset of N2 dissociation.

Valentini, Paolo; Norman, Paul; Zhang, Chonglin; Schwartzentruber, Thomas E.

2014-05-01

188

Sensing, physiological effects and molecular response to elevated CO2 levels in eukaryotes.  

Science.gov (United States)

Carbon dioxide (CO(2)) is an important gaseous molecule that maintains biosphere homeostasis and is an important cellular signalling molecule in all organisms. The transport of CO(2) through membranes has fundamental roles in most basic aspects of life in both plants and animals. There is a growing interest in understanding how CO(2) is transported into cells, how it is sensed by neurons and other cell types and in understanding the physiological and molecular consequences of elevated CO(2) levels (hypercapnia) at the cell and organism levels. Human pulmonary diseases and model organisms such as fungi, C. elegans, Drosophila and mice have been proven to be important in understanding of the mechanisms of CO(2) sensing and response. PMID:19863692

Sharabi, Kfir; Lecuona, Emilia; Helenius, Iiro Taneli; Beitel, Greg J; Sznajder, Jacob Iasha; Gruenbaum, Yosef

2009-01-01

189

Memory Scanning, Introversion-Extraversion, and Levels of Processing.  

Science.gov (United States)

Investigated was the hypothesis that high arousal increases processing of physical characteristics and reduces processing of semantic characteristics. While introverts and extroverts had equivalent scanning rates for physical features, introverts were significantly slower in searching for semantic features of category membership, indicating…

Eysenck, Michael W.; Eysenck, M. Christine

1979-01-01

190

The reorganization energy of electron transfer in nonpolar solvents: Molecular level treatment of the solvent  

International Nuclear Information System (INIS)

The intermolecular electron transfer in a solute pair consisting of pyrene and dimethylaniline is investigated in a nonpolar solvent, n-hexane. The earlier elaborated approach [M. Tachiya, J. Phys Chem. 97, 5911 (1993)] is used; this method provides a physically relevant background for separating inertial and inertialess polarization responses for both nonpolarizable and polarizable molecular level simulations. The molecular-dynamics technique was implemented for obtaining the equilibrium ensemble of solvent configurations. The nonpolar solvent, n-hexane, was treated in terms of OPLS-AA parametrization. Solute Lennard-Jones parameters were taken from the same parametrization. Solute charge distributions of the initial and final states were determined using ab initio level [HF/6-31G(d,p)] quantum-chemical calculations. Configuration analysis was performed explicitly taking into account the anisotropic polarizability of n-hexane. It is shown that the Gaussian law well describes calculated distribution functions of the solvent coordinate, therefore, the rate constant of the ET reaction can be characterized by the reorganization energy. Evaluated values of the reorganization energies are in a range of 0.03-0.11 eV and significant contribution (more then 40% of magnitude) comes from anisotropic polarizability. Investigation of the reorganization energy ? dependence on the solute pair separation distance d revealed unexpected behavior. The dependence has a very sharp peak or. The dependence has a very sharp peak at the distance d=7 A where solvent molecules are able to penetrate into the intermediate space between the solute pair. The reason for such behavior is clarified. This new effect has a purely molecular origin and cannot be described within conventional continuum solvent models

191

Investigating the effect of molecular doping on the energy levels using Seebeck measurements  

Energy Technology Data Exchange (ETDEWEB)

Molecular doping plays an essential role in small molecule based organic devices like solar cells or light-emitting diodes, because it allows to control the Fermi level in the doped layers with the corresponding advantages. However the exact mechanisms of molecular doping are still far from being fully understood. We investigate the influence of doping in different material combinations of dopants and host materials. Seebeck measurements are used to study the energetic distance between Fermi energy and transport level of doped charge transport materials, e.g. fullerene C{sub 60} or N,N,N',N'-Tetrakis(4-methoxyphenyl)-benzidine (MeO-TPD). For n-doping of C{sub 60} a novel airstable dopant is presented. For MeO-TPD and C60 a shift of the energetic distances from 180 meV down to 30 meV and from 120 meV down to 25 meV, respectively, is observed when increasing the doping concentration. Furthermore the influence of the temperature on conductivity and Seebeck measurements is shown. For MeO-TPD and C{sub 60} the activation energies of the conductivity are found to shift from 310 meV down to 210 meV and from 240 meV down to 60 meV, respectively, with increased doping concentration.

Menke, Torben; Leo, Karl; Riede, Moritz [Institut fuer Angewandte Photophysik (IAPP), TU Dresden, 01062 Dresden (Germany); Wei, Peng; Bao, Zhenan [Stanford University, CA 94305 (United States)

2011-07-01

192

Reconstructing the free-energy landscape associated to molecular motors processivity  

CERN Document Server

We propose a biochemical model providing the kinetic and energetic descriptions of the processivity dynamics of kinesin and dinein molecular motors. Our approach is a modified version of a well known model describing kinesin dynamics and considers the presence of a competitive inhibition reaction by ADP. We first reconstruct a continuous free-energy landscape of the cycle catalyst process that allows us to calculate the number of steps given by a single molecular motor. Then, we calculate an analytical expression associated to the translational velocity and the stopping time of the molecular motor in terms of time and ATP concentration. An energetic interpretation of motor processivity is discussed in quantitative form by using experimental data. We also predict a time duration of collective processes that agrees with experimental reports.

Alamilla, J Lopez

2012-01-01

193

77 FR 47337 - Project-Level Predecisional Administrative Review Process  

Science.gov (United States)

...review of each proposed action avoids the criticism sometimes leveled against postdecisional...Signature or other verification of authorship upon request; 3. The name of the proposed...Signature or other verification of authorship upon request (a scanned signature...

2012-08-08

194

Stochastic dynamics of small ensembles of non-processive molecular motors: the parallel cluster model  

CERN Document Server

Non-processive molecular motors have to work together in ensembles in order to generate appreciable levels of force or movement. In skeletal muscle, for example, hundreds of myosin II molecules cooperate in thick filaments. In non-muscle cells, by contrast, small groups with few tens of non-muscle myosin II motors contribute to essential cellular processes such as transport, shape changes or mechanosensing. Here we introduce a detailed and analytically tractable model for this important situation. Using a three-state crossbridge model for the myosin II motor cycle and exploiting the assumptions of fast power stroke kinetics and equal load sharing between motors in equivalent states, we reduce the stochastic reaction network to a one-step master equation for the binding and unbinding dynamics (parallel cluster model) and derive the rules for ensemble movement. We find that for constant external load, ensemble dynamics is strongly shaped by the catch bond character of myosin II, which leads to an increase of th...

Erdmann, Thorsten; Schwarz, Ulrich S

2013-01-01

195

Biodiversity at the Ecosystem Level - Patterns and Processes : Proceedings of the 2nd DanBIF conference, 26-27 April 2006, Aarhus University  

DEFF Research Database (Denmark)

This publication contains the presentations and discussions from the second DanBIF conference, entitled Biodiversity at the Ecosystem Level – Patterns and Processes. The questions asked at this conference were: What is biodiversity at the ecosystem level? How is it related to biodiversity at other levels of organization? How may GBIF (Global Biodiversity Information Facility) deal with ecosystem level data and informatics? The conference had two important goals. The first was to present an overview of contemporary research related to ecosystem level biodiversity and the second was to help GBIF formulate a strategy for dealing with biodiversity above the species and molecular levels and make data available for the end-users.

2009-01-01

196

Energy-Level Alignment at Interfaces between Gold and Poly(3-hexylthiophene) Films with two Different Molecular Structures  

International Nuclear Information System (INIS)

The electronic structures of the interfaces between Au and poly(3-hexylthiophene) (P3HT) films with two different molecular orientations and orderings were investigated using synchrotron radiation photoemission spectroscopy. We found that, depending on whether thermal treatment was used, the P3HT thin film adopts two different molecular orientations--parallel and perpendicular to the silicon substrate--which result in different values of the vacuum level shift and hole-injection barrier. Thus the molecular orientation and ordering of the P3HT material strongly affect the energy level alignment at the P3HT/Au interface

197

Genomic imprinting--the struggle of the genders at the molecular level.  

Science.gov (United States)

Genomic imprinting, the parent of origin-dependent expression of genes, has been discovered as a fascinating example of the control of gene expression by epigenetic processes in the human body. It affects about 100 genes, which are often involved in growth and development. In this Review, we discuss the mechanisms leading to the generation of gender-specific imprints in form of DNA methylation marks, their preservation during growth and development of the organism, and the processes that translate parental methylation marks into monoallelic gene expression. We discuss the gender-specific dimorphic nature of imprints from an evolutionary point of view and present the prevalent model that molecular imprinting mediates a conflict of interest between the parents that occurs in viviparous animals. Finally, we summarize the relevance of parental imprinting for human health. PMID:24346936

Jurkowska, Renata Z; Jeltsch, Albert

2013-12-16

198

Final Report, "Molecular Design of Hydrocarbon Oxidation Catalytic Processes"  

Energy Technology Data Exchange (ETDEWEB)

The main goal of this project had been to use model systems to correlate selectivities in partial oxidation catalysis with the presence of specific sites on the surface of the catalyst. Extensive work was performed this year on characterizing oxygen-treated nickel surfaces by chemical means. Specifically, the surface chemistry of ammonia coadsorbed with atomic oxygen on Ni(110) single-crystal surfaces was studied by temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). It was determined that at intermediate oxygen coverages direct ammonia adsorption on nickel sites is suppressed, but a new high-temperature reaction regime is generated at 400 K where NHx surface fragments are rehydrogenated concurrently with the production of water and molecular hydrogen. The extensive isotope scrambling and hydrogen transfer seen from nitrogen- to oxygen-containing surface intermediates, and the optimum yields seen for this 400 K state at intermediate oxygen coverages, strongly suggest the direct interaction of the adsorbed ammonia with oxygen atoms at the end of the –Ni–O- rows that form upon reconstruction of the surface. Hydrogen transfer between ammonia and oxygen appears to take place directly via hydrogen bonding, and to be reversible but biased towards water formation. An equilibrium is reached between the produced water and the reacting surface oxygen and hydrogen. The strong influence of the OH surface groups on the thermal chemistry of the adsorbed ammonia was interpreted in terms of the adsorbing geometry of the OH groups on the surface, and of hydrogen bonding between adsorbed OH and NH3 species. In terms of alcohol reactivity, the adsorption of 2-iodoethanol, a precursor for the preparation of 2-hydroxyethyl and oxametallacycle surface species, was found to lead to two configurations involving either just the iodine atom or both iodine and hydroxyl ends of the molecule. A complex chemical behavior starts around 140 K with the production of small amounts of ethylene and water, most likely via the concerted decomposition or disproportionation of the adsorbed molecular species. The bulk of the 2-iodoethanol decomposes at about 150 K via an initial carbon-iodine scission to form –O(H)CH2CH2– (~80%) and 2-hydroxyethyl (~20%) intermediates. Two competing reactions are involved with the subsequent conversion of the 2-hydroxyethyl species around 160 K, a reductive elimination with surface hydrogen to yield ethanol, and a ?-H elimination to surface vinyl alcohol. The –O(H)CH2CH2–, on the other hand, dehydrogenates to a –OCH2CH2– oxametallacycle species about the same temperature. Both 2-hydroxyethyl and oxametallacycle species tautomerize to acetaldehyde, around 210 K and above 250 K, respectively, and some of that acetaldehyde desorbs while the rest decomposes to hydrogen and carbon monoxide. We contend that a better understanding of the surface chemistry of oxygen-containing surfaces can lead to better selectivities in catalysis. This is arguably the most important issue in the field of catalysis in the near future, and one that impacts several technologies of interest to DOE such as the manufacturing of speciality chemicals and the control and removal of pollutants. Additional work was performed on the characterization of the chemistry of methyl and methylene adsorbed species on oxygen-treated nickel surfaces. Complex chemistry was observed involving not only hydrogenation and dehydrogenation steps, but also C-C couplings and methylene insertions to produce heavier hydrocarbons, and oxygen insertion reactions that yield oxygenates. Finally, a dual titration technique employing xenon and a chemically sensitive probe was developed to identify minority catalytic sites on oxide surfaces. In the case of oxygen-treated Ni(110) single crystals, it was found that both hydrogen transfer with adsorbed water or ammonia and certain hydrocarbon hydrogenation reactions take place at the end of the –Ni–O rows that form in this system. Carbon and nitrogen oxides, on the other hand, display no pre

Professor Francisco Zaera

2007-08-09

199

Studies on liposomes with Chlorophyll for monitoring the electromagnetic influence at molecular level  

International Nuclear Information System (INIS)

The liposomes with Chlorophyll are excellent model membranes and could be successfully used to study the electromagnetic influence at molecular level. The strong visible absorption and fluorescence of Chlorophyll allow its use as sensor for the interactions at molecular level and as a fluorescence marker; it reflects certain aspects of the supramolecular structure of the lipid phase: fluidity, lipid and liposomes aggregation. The objective of our work was to evidence athermal effect of low level, pulsed microwave (MW) fields on liposomes and to evidence the possible mechanism of interaction at molecular level. Unilamellar liposomes were obtained from multilamellar vesicles by the hand-shaken method and sonication for 30 minutes. The multilamellar vesicles were prepared using Chla /lipid films with specific molar ratio (lipid/Chla 1/10 and 1/100) and different lipids (Dipalmitoyl phosphatidylcholine, Dimirystoyl Phosphatidylcholine and Dioleoyl Phosphatidylcholine-Sigma). The films were dispersed in buffer solutions of different pH (6.2 - 7.6). The Chlorophyll was freshly extracted from spinach leaves and separated by the chromatographic method. Portions of liposome suspension (0.6 ml) were inserted into Teflon cuvettes. The samples were irradiated in series, for periods of 5-30 minutes. The exposure system was: MW generator + adapted load (shortened rectangular waveguide) + Teflon cuvette filled with sample liquid. The effect of MW irradiation is not observable on mulof MW irradiation is not observable on multilamellar vesicles, but only on small unilamellar vesicles. The MW effect is athermal, verified by conventional heating in the same range of temperatures and results in enlarging the size of vesicles. The enlarging effect of MW is opposed to the effect of ultrasounds exposure. It is not clear if effects due to MW are proportional with exposure duration; it seems that this mostly depends on the type of lipid in vesicles. The UV and VIS spectra were recorded to observe the oxidation state of the Chlorophyll and of the lipid. A connection between lipid and Chlorophyll oxidation in irradiated liposomes was observed. The fluorescence and polarization spectra were used in obtaining the transition temperature for different liposome solutions. The temperature of lipid phase transition, as monitored by fluorescence of Chla in liposomes, is not affected by MW exposure. All MW exposure effects observed on liposomes (either observed by monitoring Chla or lipids) seem to be mediated by water. Excitation of water (strong MW absorber) facilitates the hydration of polar head groups of lipids, providing the necessary physical change of lipids and thus explaining the effect of MW on SUV. (authors)

200

REDUCING ARSENIC LEVELS IN DRINKING WATER DURING IRON REMOVAL PROCESSES  

Science.gov (United States)

The presentation provides an overview of iron removal technology for the removal of arsenic from drinking water. The presentation is divided into several topic topics: Arsenic Chemistry, Treatment Selection, Treatment Options, Case Studies and Iron Removal Processes. Each topic i...

201

Low-level radioactive waste processing at nuclear power plants  

International Nuclear Information System (INIS)

This survey was limited to systems and materials used to process waste liquids contaminated with radionuclides. Since the chemical and radiological character of collected liquids may change dramatically, the survey describes waste and cleanup process streams encountered during normal outage or power production conditions. Influents containing specific organic compounds, salts, or solids common to local sources, and the special techniques developed to remove or concentrate these materials are not detailed in this report. The names and phone numbers of the individuals responsible for investigating and solving these problems, however, provides easy access to data which will save time and expense when facing abnormal processing, purchasing, or engineering challenges. The Liquid Radwaste Source Book contains information collected from 31 of 36 BWR's as well as contact information from all licensed commercial units. Since some sites share common radwaste processing facilities, not all units are represented by individual data sheets

202

A study on melting process of perylene using molecular dynamics simulation  

OpenAIRE

Melting process of perylene is investigated using molecular dynamics simulation. Some of thermodynamic properties such as potential energy and transition order parameter are calculated as a function of temperature in the range of 500 K-600 K. These calculations are performed by two different methods in NPT and NVT ensembles. The selected interaction potential is Re-squared and the simulations are performed by LAMMPS (a classic molecular dynamics code). The results show that NPT ensemble is mo...

Peyvasteh, M.; Setayeshi, S.; Vaez Zadeh, M.; Afzal Zadeh, R.

2014-01-01

203

Low-level radioactive waste from rare metals processing facilities  

International Nuclear Information System (INIS)

This paper reviews the situations at the existing Teledyne Wah Chang Co., Inc. located at Albany, Oregon, and the former Carborundum Corp./Amax Specialty Metals, Inc., facilities located at Parkersburg, West Virginia, and Akron, New York, in order to show the extent of the radioactivity problem at rare metals processing facilities and the need to identify for radiological review other rare metal and rare earth processing sites

204

Molecular field calculations of the magnetization process in CeBi  

Science.gov (United States)

The complicated magnetization processes of CeBi have been studied in terms of a molecular field model. A long range oscillatory exchange interaction between Ce ions along the [001]-axis is employed in a wave-like-form molecular field. Hm( i) = ? q?( q, ? q)cos(? qi+? q), and strong ferromagnetic interactions within the (001)-planes are included. The wavenumber dependent molecular field coefficient, ?( q, ? q), is a sensitive function of temperature for 12 K cos(? qi+? q), are also presented. A brief discussion is made on the simplified Hamiltonian.

Iwata, N.; Nishikawa, M.; Shigeoka, T.

1991-09-01

205

Comparing Different Approaches for Processing GRACE Level-1 Data  

Science.gov (United States)

Three different approaches for determining global gravity field solutions from GRACE satellites are presented and compared. Gravity field solutions - the so-called GRACE level-2 data - are mainly spherical harmonic expansions of the Earth's gravitational potential and are widely used by the geosciences community. Level-2 data are obtained via the functional modeling of GRACE level-1 data which are in principle the GRACE orbit, observed by GPS high-low and K-band low-low satellite-to-satellite tracking as well as on-board accelerometry. There are several approaches to connect the Earth's gravitational potential to the level-1 observations. In this research study we compare three different approaches using simulated GRACE level-1 data. The methods being considered here are the acceleration approach, the energy balance approach and the integral equation method. This work is part of the cooperation between Institut für Erdmessung (IfE) and Albert Einstein Institut (AEI) at Leibniz Universität Hannover, Deutsches Geodätisches Forschungsinstitut (DGFI) and Bayerische Kommission für die Internationale Erdmessung (BEK) in Munich and Deutsches GeoforschungsZentrum (GFZ) in Potsdam. Each institution will apply one of the above mentioned methods. Features and typical characteristics of each approach are discussed.

Naeimi, Majid

2010-05-01

206

Polarization-induced renormalization of molecular levels at metallic and semiconducting surfaces  

DEFF Research Database (Denmark)

On the basis of first-principles G0W0 calculations we systematically study how the electronic levels of a benzene molecule are renormalized by substrate polarization when physisorbed on different metallic and semiconducting surfaces. The polarization-induced reduction in the energy gap between occupied and unoccupied molecular levels is found to scale with the substrate density of states at the Fermi level (for metals) and substrate band gap (for semiconductors). These conclusions are further supported by self-consistent GW calculations on simple lattice models. By expressing the electron self-energy in terms of the substrate’s joint density of states we relate the level shift to the surface electronic structure, thus providing a microscopic explanation of the trends in the GW and G0W0 calculations. While image charge effects are not captured by semilocal and hybrid exchange-correlation functionals, we find that error cancellations lead to remarkably good agreement between the G0W0 and Kohn-Sham energies for the occupied orbitals of the adsorbed molecule.

García Lastra, Juan Maria; Rostgaard, Carsten

2009-01-01

207

Dynamical image-charge effect in molecular tunnel junctions : Beyond energy level alignment  

DEFF Research Database (Denmark)

When an electron tunnels between two metal contacts it temporarily induces an image charge (IC) in the electrodes which acts back on the tunneling electron. It is usually assumed that the IC forms instantaneously such that a static model for the image potential applies. Here we investigate how the finite IC formation time affects charge transport through a molecule suspended between two electrodes. For a single-level model, an analytical treatment shows that the conductance is suppressed by a factor Z(2), where Z is the quasiparticle renormalization factor, compared to the static IC approximation. We show that Z can be expressed either in terms of the plasma frequency of the electrode or as the overlap between electrode wave functions corresponding to an empty and filled level, respectively. First-principles GW calculations for benzene-diamine connected to gold electrodes show that the dynamical corrections can reduce the conductance by more than a factor of two when compared to static GW or density functional theory where the molecular energy levels have been shifted to match the exact quasiparticle levels.

Jin, Chengjun; Thygesen, Kristian Sommer

2014-01-01

208

Quantum simulation and quantum information processing with molecular dipolar crystals  

International Nuclear Information System (INIS)

In this thesis interactions between dipolar crystals and neutral atoms or separated molecules have been investigated. They were motivated to realize new kinds of lattice models in mixtures of atoms and polar molecules where an MDC functions as an underlying periodic lattice structure for the second species. Such models bring out the peculiar features of MDC's, that include a controllable, potentially sub-optical wavelength periodicity and strong particle phonon interactions. Only stable collisional configurations have been investigated, excluding chemical reactions between the substituents, and crystal distortions beyond the scope of perturbation theory. The system was treated in the polaron picture where particles of the second species are dressed by surrounding crystal phonons. To describe the competition between coherent and incoherent dynamics of the polarons, a master equation in the Brownian motion limit was used with phonons treated as a thermal heat bath. It was shown analytically that in a wide range of realistic parameters the corrections to the coherent time evolution are small, and that the dynamics of the dressed particles can be described by an effective extended Hubbard model with controllable system parameters. The last chapter of this thesis contains a proposal for QIP with cold polar molecules that, in contrast to previous works, uses an MDC as a quantum register. It was motivated by the unique features of dipolar molecules and to exploit the peculiapolar molecules and to exploit the peculiar physical conditions in dipolar crystals. In this proposal the molecular dipole moments were tailored by non-local fields to include a small, switchable, state-dependent dipole moment in addition to the large internal state independent moment that stabilizes the crystal. It was shown analytically that a controllable, non-trivial phonon-mediated interaction can be generated that exceeds non-trivial, direct dipole-dipole couplings. The addressability problem due to high crystal densities was overcome by the use of marker qubits that locally manipulate the phononic structure. This enabled the implementation of qubit operations in the crystal at pre-specified lattice site using otherwise global addressing only with negligible decoherence. Finally a specific two-layer setup is outlined that can be scaled to arbitrary sizes by including multi-layer structures realized under optical trapping conditions with multiple marker molecules. (author)

209

Effects of Stimulus Type and Level Repetition on Content-Level Binding in Global/Local Processing  

OpenAIRE

The processing and representation of hierarchical objects not only involves the identification of information at the different levels, but also the binding of the identified content to its respective level. Whereas identification is well understood, little is known about content-level binding. In a recent study, however, it has been shown that attentional priming of certain spatial frequencies is advantageous for this binding. Therefore, the present study investigated effects of related facto...

RonaldHübner

2011-01-01

210

Photochemical processes in laser ablation of organic solids: Molecular dynamics study  

Science.gov (United States)

In this thesis, a comprehensive study of the effect of the photochemical processes on laser ablation mechanisms has been conducted using molecular dynamics simulations. We developed a new concept for modeling photochemical processes in laser ablation of organic films using a mesoscopic coarse-grain breathing sphere model for molecular dynamics simulations. The main advantage of our model is the ability to study the dynamics of the system at the mesoscopic length scale, a regime that is not accessible either with atomistic or continuum computational methods. The photodecomposition of the excited molecules and the chemical reaction patterns in our simulations are based on the photochemistry of chlorobenzene due to ease of its fragmentation and available experimental data. Interpretation of the experimental data is the main objective of our theoretical efforts. Molecular dynamics simulations are used to investigate the effect of photochemical processes on molecular ejection mechanisms in 248-nm laser irradiation of organic solids. Photochemical reactions are found to release additional energy into the irradiated sample and decrease the average cohesive energy, therefore decreasing the value of the ablation threshold. The yield of emitted fragments becomes significant only above the ablation threshold. Below the ablation threshold, only the most volatile photoproduct, HCl, is ejected in very small amounts, whereas the remainder of photoproducts are trapped inside the sample. The presence of photochemical decomposition processes and subsequent chemical reactions changes the temporal and spatial energy deposition profile from pure photothermal ablation. The chemical reactions create an additional local pressure build up and, as a result, generate a strong and broad acoustic pressure wave propagating toward the bottom of the computational cell. The strong pressure wave in conjunction with the temperature increase in the absorbing region causes the ejection of hot massive molecular clusters. These massive clusters later disintegrate in the plume into the smaller clusters and monomers due to ongoing chemical reactions. The ejection and disintegration of big clusters result in the higher material removal rates and higher plume density. The results from our molecular dynamics simulations are in good agreement with experiment and provide microscopic perspective of photochemical processes in laser ablation to experimental investigations. The ablation of material that is onset by pure photochemical processes has been investigated by molecular dynamics simulations. The simulations reveal that ablation by purely photochemical processes is accompanied by the ejection of relatively cold massive molecular clusters from the surface of the sample. The top of the plume exhibits high temperatures whereas the residual part of the sample is cold. The removal of the damaged material through big molecular cluster ejection is consistent with experimental observations of low heat damage of material. (Abstract shortened by UMI.)

Yingling, Yaroslava G.

211

Evaluation of the degradation effect on the processability of high molecular weight polypropylene  

International Nuclear Information System (INIS)

One way to improve the processability of high molecular weight and melt strength of Polypropylene (PP) is reducing its molecular weight by chain scission with increase of flow index. Nevertheless, the more significant occurrence of chain scission in its structure, further improved its processability is at expense of physical properties. It is well known that the high energy radiation creates free radicals in the polymer chains that subsequently stabilize forming structures. These structures composed by low molecular weight chains and by grafted, branched and crosslinked chains modify the physical and chemical properties of the polymer, depending of their distribution. The low molecular weight chains become from the degradation process by high energy irradiation, which decreases the melt strength and improves its processability. So, this work has the objective to evaluate the degradation of the high molecular weight PP using different irradiation doses. Two kinds of PP samples were utilized. The first one, without additive, presented a flow index of 1.9 g/10 min, and the second, additivated with 0.2 wt % of antioxidant phenolic, Irganox 1010, with a flow index of 0.9 g/10 min. These samples were irradiated with doses of 12.5 and 20.0 kGy. The results of flow index and melt strength obtained with these two kinds of samples showed the antioxidant and the radiation action. (author)

212

Fast analysis of molecular dynamics trajectories with graphics processing units-Radial distribution function histogramming  

International Nuclear Information System (INIS)

The calculation of radial distribution functions (RDFs) from molecular dynamics trajectory data is a common and computationally expensive analysis task. The rate limiting step in the calculation of the RDF is building a histogram of the distance between atom pairs in each trajectory frame. Here we present an implementation of this histogramming scheme for multiple graphics processing units (GPUs). The algorithm features a tiling scheme to maximize the reuse of data at the fastest levels of the GPU's memory hierarchy and dynamic load balancing to allow high performance on heterogeneous configurations of GPUs. Several versions of the RDF algorithm are presented, utilizing the specific hardware features found on different generations of GPUs. We take advantage of larger shared memory and atomic memory operations available on state-of-the-art GPUs to accelerate the code significantly. The use of atomic memory operations allows the fast, limited-capacity on-chip memory to be used much more efficiently, resulting in a fivefold increase in performance compared to the version of the algorithm without atomic operations. The ultimate version of the algorithm running in parallel on four NVIDIA GeForce GTX 480 (Fermi) GPUs was found to be 92 times faster than a multithreaded implementation running on an Intel Xeon 5550 CPU. On this multi-GPU hardware, the RDF between two selections of 1,000,000 atoms each can be calculated in 26.9 s per frame. The multi-GPU RDF algorithms describrame. The multi-GPU RDF algorithms described here are implemented in VMD, a widely used and freely available software package for molecular dynamics visualization and analysis.

213

Elevated copper ion levels as potential cause of impaired kinesin-dependent transport processes.  

Science.gov (United States)

Copper is a trace element required to maintain essential life processes. In healthy organisms, copper metabolism is well balanced. If this balance is destroyed, the cellular level of free copper might increase and cause toxic effects. So far, the molecular mechanisms of copper intoxication are understood only partly. The present study revealed that the kinesin-dependent transport system is strongly affected by copper(II) ions. Both the microtubules, along which kinesin moves, and the kinesin itself were found to be the target structures of copper ions: Microtubule formation was suppressed by copper ions (IC50 26-70 µM) apparently chiefly by inhibition of binding of microtubule-associated proteins to tubulin. This inhibition could be widely compensated by the microtubule-stabilising agent paclitaxel. In addition, copper ions strongly inhibited the ATPase activity of neuron-specific kinesin KIF5A. At final KIF5A concentration of 112 nM, an IC50 of 1.3 µM was determined. Correspondingly, the motility activity of KIF5A, measured as velocity of microtubules gliding across a kinesin-covered surface, was blocked. The effects of copper ions on microtubules and on KIF5A are suggested to contribute to impaired transport processes within brain and other organs in cases of copper ion surplus. PMID:24853401

Böhm, Konrad J

2015-04-01

214

Impacts of pr-10a Overexpression at the Molecular and the Phenotypic Level  

Directory of Open Access Journals (Sweden)

Full Text Available Biotechnological approaches using genetic modifications such as homologous gene overexpression can be used to decode gene functions under well-defined circumstances. However, only the recording of the resulting phenotypes allows inferences about the impact of the modification on the organisms’ evolutionary, ecological or economic performance. We here compare a potato wild-type cell line with two genetically engineered cell cultures homologously overexpressing Pathogenesis Related Protein 10a (pr-10a. A detailed analysis of the relative gene-expression patterns of pr-10a and its regulators sebf and pti4 over time provides insights into the molecular response of heterotrophic cells to distinct osmotic and salt-stress conditions. Furthermore, this system serves as an exemplar for the tracing of respiration kinetics as a faster and more sensitive alternative to the laborious and time-consuming recording of growth curves. The utility and characteristics of the resulting data type and the requirements for its appropriate analysis are figured out. It is demonstrated how this novel type of phenotypic information together with the gene-expression-data provides valuable insights into the effect of genetic modifications on the behaviour of cells on both the molecular and the macroscopic level.

Markus Göker

2013-07-01

215

Control of molecular organization and energy level alignment by an electronically nanopatterned boron nitride template.  

Science.gov (United States)

Suitable templates to steer the formation of nanostructure arrays on surfaces are indispensable in nanoscience. Recently, atomically thin sp(2)-bonded layers such as graphene or boron nitride (BN) grown on metal supports have attracted considerable interest due to their potential geometric corrugation guiding the positioning of atoms, metallic clusters or molecules. Here, we demonstrate three specific functions of a geometrically smooth, but electronically corrugated, sp(2)/metal interface, namely, BN/Cu(111), qualifying it as a unique nanoscale template. As functional adsorbates we employed free-base porphine (2H-P), a prototype tetrapyrrole compound, and tetracyanoquinodimethane (TCNQ), a well-known electron acceptor. (i) The electronic moirons of the BN/Cu(111) interface trap both 2H-P and TCNQ, steering self-organized growth of arrays with extended molecular assemblies. (ii) We report an effective decoupling of the trapped molecules from the underlying metal support by the BN, which allows for a direct visualization of frontier orbitals by scanning tunneling microscopy (STM). (iii) The lateral molecular positioning in the superstructured surface determines the energetic level alignment; i.e., the energy of the frontier orbitals, and the electronic gap are tunable. PMID:24328081

Joshi, Sushobhan; Bischoff, Felix; Koitz, Ralph; Ecija, David; Seufert, Knud; Seitsonen, Ari Paavo; Hutter, Jürg; Diller, Katharina; Urgel, José I; Sachdev, Hermann; Barth, Johannes V; Auwärter, Willi

2014-01-28

216

A study on melting process of perylene using molecular dynamics simulation  

Directory of Open Access Journals (Sweden)

Full Text Available Melting process of perylene is investigated using molecular dynamics simulation. Some of thermodynamic properties such as potential energy and transition order parameter are calculated as a function of temperature in the range of 500 K-600 K. These calculations are performed by two different methods in NPT and NVT ensembles. The selected interaction potential is Re-squared and the simulations are performed by LAMMPS (a classic molecular dynamics code. The results show that NPT ensemble is more appropraite for the study of melting process than NVT ensemble and shows a good agreement with experimental melting temperature.

M Peyvasteh

2014-11-01

217

Bibliography of atomic and molecular processes. Volume 1, 1978-1981  

Energy Technology Data Exchange (ETDEWEB)

This annotated bibliography lists 10,676 works on atomic and molecular processes reported in publications dated 1978-1981. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the county of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory.

Barnett, C.F.; Crandall, D.H.; Farmer, B.J. (comps.)

1982-10-01

218

Bibliography of atomic and molecular processes. Volume 1, 1978-1981  

International Nuclear Information System (INIS)

This annotated bibliography lists 10,676 works on atomic and molecular processes reported in publications dated 1978-1981. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the county of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory

219

Advances in low-level color image processing  

CERN Document Server

Color perception plays an important role in object recognition and scene understanding both for humans and intelligent vision systems. Recent advances in digital color imaging and computer hardware technology have led to an explosion in the use of color images in a variety of applications including medical imaging, content-based image retrieval, biometrics, watermarking, digital inpainting, remote sensing, visual quality inspection, among many others. As a result, automated processing and analysis of color images has become an active area of research, to which the large number of publications of the past two decades bears witness. The multivariate nature of color image data presents new challenges for researchers and practitioners as the numerous methods developed for single channel images are often not directly applicable to multichannel  ones. The goal of this volume is to summarize the state-of-the-art in the early stages of the color image processing pipeline.

Smolka, Bogdan

2014-01-01

220

Fabrication of a molecular-level multilayer film on organic polymer surfaces via chemical bonding assembly.  

Science.gov (United States)

A fresh multilayer film was fabricated on a molecular level and successfully tethered to the surface of a hydroxylated organic substrate via chemical bonding assembly (CBA). Sulfate anion groups (SO4-) were preintroduced onto the surface of biaxially oriented polypropylene (BOPP) films via a reference method. Upon hydrolysis of the SO4- groups, hydroxyl groups (--OH) were formed that subsequently acted as initial reagents for a series of alternate reactions with terephthalyl chloride (TPC) and bisphenol A (BPA). A stable and well-defined multilayer film was thus fabricated via the CBA method. As a result of the nanoscale multilayer fresh film being abundant with reactive groups, it is believed that the film and its fabrication method should provide a fundamental platform for further surface functionalization and direct the design of advanced materials with desired properties. PMID:17279660

Zhao, Hongchi; Yang, Peng; Deng, Jianping; Liu, Lianying; Zhu, Jianwu; Sui, Yuan; Lu, Jiaoming; Yang, Wantai

2007-02-13

221

Level 1 remedial investigation work plan, 300 Area Process Ponds  

Energy Technology Data Exchange (ETDEWEB)

This report discusses the objectives of the site characterization for the 300 Area Process Ponds which are to identify and quantify contamination at the ponds and to estimate their potential impact on human health and the environment. The results of the site characterization will be used to identify any future actions related to contamination at the site and to identify any additional data requirements needed to support selection of a remedial action. 9 refs., 12 figs., 8 tabs.

1987-06-01

222

The fabrication of rare earth covalent luminescent hybrid materials with potential molecular bridge by in situ sol-gel process  

International Nuclear Information System (INIS)

1,2,4-Benzenetricar boxylic acid (abbreviated as TMA) was modified to achieve a functional molecular bridge (TMA-APMES) with double reactivity by the reaction with a cross-linking molecule (3-aminopropyl-methyl-diethoxylsiliane, APMES). The modified functional ligand further behaves as a bridge both coordinates to Ln3+ through oxygen atom and occurs in situ sol-gel process with matrix precursor (tetraethoxysilane, TEOS) through co-hydrolysis and co-polycondensation reaction. Then a novel molecular hybrid material (named as hybrid Ln3+) with double chemical bond (Tb-O coordination bond and Si-O covalent bond) resulted. Ultraviolet absorption, phosphorescence, and fluorescence spectra were applied to characterize the photophysical properties of the obtained hybrid material. The strong luminescence of Tb3+ substantiates optimum energy couple and effective intramolecular energy transfer between the triplet state energy of modified ligand bridge and emissive energy level of Tb3+

223

Implications of the admixture process in skin color molecular assessment.  

Science.gov (United States)

The understanding of the complex genotype-phenotype architecture of human pigmentation has clear implications for the evolutionary history of humans, as well as for medical and forensic practices. Although dozens of genes have previously been associated with human skin color, knowledge about this trait remains incomplete. In particular, studies focusing on populations outside the European-North American axis are rare, and, until now, admixed populations have seldom been considered. The present study was designed to help fill this gap. Our objective was to evaluate possible associations of 18 single nucleotide polymorphisms (SNPs), located within nine genes, and one pseudogene with the Melanin Index (MI) in two admixed Brazilian populations (Gaucho, N?=?352; Baiano, N?=?148) with different histories of geographic and ethnic colonization. Of the total sample, four markers were found to be significantly associated with skin color, but only two (SLC24A5 rs1426654, and SLC45A2 rs16891982) were consistently associated with MI in both samples (Gaucho and Baiano). Therefore, only these 2 SNPs should be preliminarily considered to have forensic significance because they consistently showed the association independently of the admixture level of the populations studied. We do not discard that the other two markers (HERC2 rs1129038 and TYR rs1126809) might be also relevant to admixed samples, but additional studies are necessary to confirm the real importance of these markers for skin pigmentation. Finally, our study shows associations of some SNPs with MI in a modern Brazilian admixed sample, with possible applications in forensic genetics. Some classical genetic markers in Euro-North American populations are not associated with MI in our sample. Our results point out the relevance of considering population differences in selecting an appropriate set of SNPs as phenotype predictors in forensic practice. PMID:24809478

Cerqueira, Caio Cesar Silva de; Hünemeier, Tábita; Gomez-Valdés, Jorge; Ramallo, Virgínia; Volasko-Krause, Carla Daiana; Barbosa, Ana Angélica Leal; Vargas-Pinilla, Pedro; Dornelles, Rodrigo Ciconet; Longo, Danaê; Rothhammer, Francisco; Bedoya, Gabriel; Canizales-Quinteros, Samuel; Acuña-Alonzo, Victor; Gallo, Carla; Poletti, Giovanni; González-José, Rolando; Salzano, Francisco Mauro; Callegari-Jacques, Sídia Maria; Schuler-Faccini, Lavínia; Ruiz-Linares, Andrés; Cátira Bortolini, Maria

2014-01-01

224

Corrosion and failure processes in high-level waste tanks  

Energy Technology Data Exchange (ETDEWEB)

A large amount of radioactive waste has been stored safely at the Savannah River and Hanford sites over the past 46 years. The aim of this report is to review the experimental corrosion studies at Savannah River and Hanford with the intention of identifying the types and rates of corrosion encountered and indicate how these data contribute to tank failure predictions. The compositions of the High-Level Wastes, mild steels used in the construction of the waste tanks and degradation-modes particularly stress corrosion cracking and pitting are discussed. Current concerns at the Hanford Site are highlighted.

Mahidhara, R.K.; Elleman, T.S.; Murty, K.L. [North Carolina State Univ., Raleigh, NC (United States)

1992-11-01

225

The role of core levels in scintillation processes  

International Nuclear Information System (INIS)

The Auger decay of a core hole results in appearance of several strongly correlated excitations. This excited region strongly polarizes the lattice and thus the defect creation is possible. In all cases the core hole causes the strong local perturbation of electronic and lattice subsystems. The creation of such excited region with mutual relaxation of correlated electrons and holes can result in the increase of the efficiency of energy transfer to activators, acceleration of the luminescence kinetics, and the appearance of radiation-induced luminescence centers. These effects have been studied using VUV and soft X-ray synchrotron radiation, when the selective excitation of different core levels is possible

226

[Implementation on the operating level of the nursing process].  

Science.gov (United States)

The development of the nursing care attention process guided through the PDCA. (plan, do, check, act), provides a continuous improvement of our actual context. The meaning of PDCA is translated as VIDA for: view, implementation, discernment, at just. For its application it takes in view the change theory of Kurt Lewin. This paper provides the results of the Implementation stage using different approaches as technical care, education, administration and research. These strategies show that people did not express their feelings, beliefs and their own expectations and autonomy in nursing care. They even do not develop their citizenship, right of living and being able to grow. PMID:10734939

Villalobos, N A

1999-01-01

227

Investigation of material removal mechanism of silicon wafer in the chemical mechanical polishing process using molecular dynamics simulation method  

Energy Technology Data Exchange (ETDEWEB)

Chemical mechanical polishing (CMP) technology, being the mainstream technique of acquiring global planarization and nanometer level surface, has already become an attractive research item. In the case of CMP process, the indentation depth lies in the range of nanometer or sub-nanometer, huge hydrostatic pressure induced in the local deformation area which makes the material removal and surface generation process different from traditional manufacturing process. In order to investigate the physical essence of CMP technique, the authors carry out molecular dynamics (MD) analysis of chemical mechanical polishing of a silicon wafer. The simulation result shows that huge hydrostatic pressure is induced in the local area and leads to the silicon atom transform from the classical diamond structure ({alpha} silicon) to metal structure ({beta} silicon). This important factor results in the ductile fracture of silicon and then in the acquisition of a super-smooth surface. (orig.)

Han, Xuesong; Yu, Siyuan [Tianjin University, Laboratory of Robot and Automobile Technology, School of Mechanical Engineering, Tianjin (China); Hu, Yuanzhong [Tsinghua University, State Key Laboratory of Tribology, Beijing (China)

2009-06-15

228

Novel in situ activity assays for the quantitative molecular analysis of neurodegenerative processes in the retina.  

Science.gov (United States)

The mechanisms of neuronal cell death are still only poorly understood, which has hindered the advancement of therapies for many currently untreatable neurodegenerative diseases. This calls for the development of new methods which reveal critical molecular mechanisms of the celldeath machinery with both high sensitivity and cellular resolution. Using animal models for hereditary neurodegeneration in the retina, we have developed or adapted different biochemical assays to determine the enzymatic activities of calpain, poly-ADP-ribose-polymerase (PARP), and histone deacetylase (HDAC) directly and in situ. Additionally, the enzymatic activity of cGMP-dependent protein kinase (PKG) was assessed indirectly using in situ immunohistological techniques to detect PKG-activity-dependent products. Combining these assays with in situ cell death markers revealed close temporospatial correlations, suggesting causal connections between the PKG, HDAC, PARP and calpain activities and neuronal cell death. Using different pharmacological and genetic manipulations, causality could indeed be demonstrated. Surprisingly, the often dramatic rises in metabolic activities didnot match by corresponding increases in expression, highlighting the importance of analyses of protein activities at the cellular level. The above mentioned studies identified a number of metabolic processes previously unknownto be involved in inherited retinal degeneration. Comparing different animal retinal degeneration models uncovered striking similarities in enzymatic activities, suggesting a generality of the destructive pathways. Taken together, these findings provided a number of novel targets for neuroprotection and as such opened up new perspectives for the therapy of hereditary neurodegeneration in the retina and possibly other parts of the central nervous system. PMID:24934347

Ekström, P A R; Ueffing, M; Zrenner, E; Paquet-Durand, F

2014-01-01

229

Accretion-Driven Turbulence as Universal Process: Galaxies, Molecular Clouds, and Protostellar Disks  

CERN Document Server

When cosmic structures form, they grow in mass via accretion from their surrounding environment. The energy associated with this transport of material provides a ubiquitous source of internal turbulence. We propose that accretion will drive turbulent motions in a wide range of astrophysical objects and study this process in the case of galaxies, molecular clouds and protoplanetary disks. We use a combination of numerical simulations and analytical arguments to predict the level of turbulence as a function of the accretion rate, the dissipation scale, and the density contrast, and compare with observational data. We find that in Milky Way type galaxies the turbulence in the non star-forming outer parts of the disk can be explained by accretion, provided that the galaxies accrete at a rate comparable to the rate at which they form stars. We note that the extended outer disk carries the bulk of the turbulent energy in the galaxy. Our approach fails for dwarf galaxies and we expect other sources to dominate. We c...

Klessen, Ralf S

2009-01-01

230

High level radioactive waste vitrification process equipment component testing  

International Nuclear Information System (INIS)

Remote operability and maintainability of vitrification equipment were assessed under shielded-cell conditions. The equipment tested will be applied to immobilize high-level and transuranic liquid waste slurries that resulted from plutonium production for defense weapons. Equipment tested included: a turntable for handling waste canisters under the melter; a removable discharge cone in the melter overflow section; a thermocouple jumper that extends into a shielded cell; remote instrument and electrical connectors; remote, mechanical, and heat transfer aspects of the melter glass overflow section; a reamer to clean out plugged nozzles in the melter top; a closed circuit camera to view the melter interior; and a device to retrieve samples of the glass product. A test was also conducted to evaluate liquid metals for use in a liquid metal sealing system

231

Consolidation of slow or fast but not moderately evolving genes at the level of pathways and processes.  

Science.gov (United States)

Conservatism versus innovation is probably the most important dichotomy of all evolving systems. In molecular evolution the distinction between conservative (negative) selection, innovative (positive) selection and unconstrained evolution (drift) is usually ambiguous at the gene level. Only rare cases with the ratio of nonsynonymous to synonymous nucleotide substitutions above unity (dN/dS>1) are thought to be due to positive selection, whereas the lower dN/dS ratio may indicate negative selection in combination with drift. The density of the dN/dS ratio for orthologous genes forms a unimodal distribution where no particular regions can be discerned. Here it is shown that at the level of overrepresented pathways and processes the picture is strikingly different. The distribution is strongly polarized with a wide completely depressed middle part. This three-phase distribution is very robust. It is observed with various substitution models and remains at very low significance of overrepresentation (up to pprocesses. The effect is demonstrated for different phylogenetic distances: from human to other primates, mammals and vertebrates. This approach suggests estimating the boundaries for conservative and innovative selection using the pathway/process level. Emphasizing the role of a critical mass of negatively or positively selected genes in a pathway/process, it can elucidate how the bridge between 'tinkering' at the gene level and 'design' at the higher levels is forming. PMID:25707747

Vinogradov, Alexander E

2015-04-25

232

Constant current charging process of MV-level Marx generator  

International Nuclear Information System (INIS)

A 4 MV pre-triggered Marx generator charged with series resistor has been designed. For better output property, higher charging efficiency and lower voltage difference between stages, the study conducted the analytic solution of its constant current charging (CCC) process. The results show that the voltage differences between different stages of capacitors are in direct proportion to charging resistance, capacitance and charging speed, but are independent of time; the charging efficiency improves with time, but is independent of charging speed. This solution is universally applicable. The simulation of CCC for the Marx generator was done with PSpice, and the results agree with the analytic solution. Compared to constant voltage charging (CVC) with 10 k? charging resistors, 400 nF capacitors and 10 kV/s charging speed, the charging efficiency of CCC is 90%, double that of CVC and the charging time is only one third. (authors)

233

Solution-phase laser processing of ?-conjugated polymers: Switching between different molecular states  

International Nuclear Information System (INIS)

Liquid-phase laser processing, where the laser-irradiated target material is immersed in water for cooling, has been reported as a promising processing technique for thermally fragile organic materials. Although nanometer-sized particles have been reported to be obtained with the liquid-phase laser processing, the physical property did not change because quantum-mechanical size effect does not exhibit itself in the zero-radius Frenkel excitons. In the present study, we step further to use solution droplets as a target material, where organic molecules are molecularly dispersed in organic solvent and, therefore, expected to easily alter the conformation and the energy state upon laser irradiation. Small volume organic solvent is quickly evaporated upon laser irradiation, letting the bare organic molecule placed in water and rapidly cooled. To prevent the chemical decomposition of the target ?-conjugated molecule, the specimen was resonantly irradiated by a ns-pulse green laser, not by a conventional UV laser. When the solid state spin-coat film made from MEH-PPV chloroform solution was used as a irradiation target immersed in water, resulting MEH-PPV particles showed similar photoluminescence (PL) like the PL of the spin-coat film and PL of the chloroform solution, including the 0?1, 0?2 vibrational transitions: this indicates that the energy levels were not modified from the spin-coat film. In comparison, when tiny droplets of MEH-PPV chloroform solution (orange MEH-PPV chloroform solution (orange color) were suspended in water, laser irradiation gave rise to yellow MEH-PPV particles which showed 550 nm and 530 nm PL (type B), blue-shifted from the spin-coat film PL 580 nm (type A), suggesting a successful phase transition of MEH-PPV polymer to type B. Further solution-phase laser processing left the type B state unchanged. The irreversible phase transition from type A to type B suggests that the type B ground state has lower energy than type A, which is consistent with the blue-shifted PL of type B, provided that the excited state energy is similar between the two states. Thermal annealing up to 200°C of type A state did not give rise to type B state, which indicates that the activation potential between the two states is higher than the thermal energy at 200°C, and that only the proposed solution-phase laser processing enables the system to cross over this potential.

234

Determination of cadmium at ultra-trace levels by CPE-molecular fluorescence combined methodology  

Energy Technology Data Exchange (ETDEWEB)

A highly sensitive micelle-mediated extraction methodology for the preconcentration and determination of trace levels of cadmium by molecular fluorescence has been developed. Metal was complexed with o-phenanthroline (o-phen) and eosin (eo) at pH 7.6 in buffer Tris medium and quantitatively extracted into a small volume of surfactant-rich phase of PONPE 7.5 after centrifugating. The chemical variables affecting cloud point extraction (CPE) were evaluated and optimized. The RSD for six replicates of cadmium determinations at 0.84 {mu}g L{sup -1} level was 1.17%. The linearity range using the preconcentration system was between 2.79 x 10{sup -3} {mu}g L{sup -1} and 2.81 {mu}g L{sup -1} with a correlation coefficient of 0.99. Under the optimal conditions, it obtained a LOD of 8.38 x 10{sup -4} {mu}g L{sup -1} and LOQ of 2.79 x 10{sup -3} {mu}g L{sup -1}. The method presented good sensitivity and selectivity and was applied to the determination of trace amounts of cadmium in commercially bottled mineral water, tap water and water well samples with satisfactory results. The proposed method is an innovative application of CPE-luminescence to metal analysis comparable in sensitivity and accuracy with atomic spectroscopies.

Talio, Maria Carolina [Instituto de Quimica de San Luis (INQUISAL-CONICET), Chacabuco y Pedernera, 5700 San Luis (Argentina); Luconi, Marta O. [Area de Quimica Analitica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Masi, Adriana N. [Area de Bromatologia- Ensayo y Valoracion de Medicamentos, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Instituto de Quimica de San Luis (INQUISAL-CONICET), Chacabuco y Pedernera, 5700 San Luis (Argentina); Fernandez, Liliana P., E-mail: lfernand@unsl.edu.ar [Area de Quimica Analitica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Instituto de Quimica de San Luis (INQUISAL-CONICET), Chacabuco y Pedernera, 5700 San Luis (Argentina)

2009-10-15

235

23 CFR 630.1008 - State-level processes and procedures.  

Science.gov (United States)

...State-level processes and procedures, data and information...zone assessment and management procedures. States should...related transportation management and traffic control...State processes and procedures. (e)...

2010-04-01

236

Ultrafilter Conditions for High Level Waste Sludge Processing  

International Nuclear Information System (INIS)

An evaluation of the optimal filtration conditions was performed based on test data obtained from filtration of a High Level Waste Sludge sample from the Hanford tank farms. This evaluation was performed using the anticipated configuration for the Waste Treatment Plant at the Hanford site. Testing was performed to identify the optimal pressure drop and cross flow velocity for filtration at both high and low solids loading. However, this analysis indicates that the actual filtration rate achieved is relatively insensitive to these conditions under anticipated operating conditions. The maximum filter flux was obtained by adjusting the system control valve pressure from 400 to 650 kPa while the filter feed concentration increased from 5 to 20 wt%. However, operating the system with a constant control valve pressure drop of 500 kPa resulted in a less than 1% reduction in the average filter flux. Also note that allowing the control valve pressure to swing as much as +/- 20% resulted in less than a 5% decrease in filter flux

237

IAEA technical meeting on 'Technical aspects of atomic and molecular data processing and exchange'. Summary report  

International Nuclear Information System (INIS)

The proceedings of the IAEA Advisory Group Meeting on 'Technical Aspects of Atomic and Molecular Data Processing and Exchange' (17th Meeting of A+M Data Centres and ALADDIN Network), held on 6-7 October, 2003 in Vienna, Austria are briefly described. The meeting conclusions and recommendations on the priorities in A+M data compilation and evaluation, and on the technical aspects of data processing, exchange, and distribution are also presented. (author)

238

Signal processing for molecular and cellular biological physics: an emerging field  

OpenAIRE

Recent advances in our ability to watch the molecular and cellular processes of life in action—such as atomic force microscopy, optical tweezers and Forster fluorescence resonance energy transfer—raise challenges for digital signal processing (DSP) of the resulting experimental data. This article explores the unique properties of such biophysical time series that set them apart from other signals, such as the prevalence of abrupt jumps and steps, multi-modal distributions and autocorrelat...

Little, Max A.; Jones, Nick S.

2013-01-01

239

Molecular Chemical Engines: Pseudo-Static Processes and the Mechanism of Energy Transduction  

OpenAIRE

We propose a simple theoretical model for a molecular chemical engine that catalyzes a chemical reaction and converts the free energy released by the reaction into mechanical work. Binding and unbinding processes of reactant and product molecules to and from the engine are explicitly taken into account. The work delivered by the engine is calculated analytically for infinitely slow (``pseudo-static'') processes, which can be reversible (quasi-static) or irreversible, control...

Sasaki, Kazuo

2005-01-01

240

The interaction of CO2 with amines as molecular control factor in catalytic processes  

OpenAIRE

The present thesis deals with the interaction of CO2 and amines as molecular control factor to influence different kinds of selectivities in various catalytic processes. The reversibility of the Lewis acid-base reaction between CO2 and amines has been applied in numerous reaction and separation processes and chapter I gives a short overview of the different areas. Up to date this interaction has not been used to steer the selectivity of a reaction and in this context, switchable solvents are ...

Wispelaere, Irene Martine

2014-01-01

241

Stochastic dynamics of small ensembles of non-processive molecular motors: The parallel cluster model  

International Nuclear Information System (INIS)

Non-processive molecular motors have to work together in ensembles in order to generate appreciable levels of force or movement. In skeletal muscle, for example, hundreds of myosin II molecules cooperate in thick filaments. In non-muscle cells, by contrast, small groups with few tens of non-muscle myosin II motors contribute to essential cellular processes such as transport, shape changes, or mechanosensing. Here we introduce a detailed and analytically tractable model for this important situation. Using a three-state crossbridge model for the myosin II motor cycle and exploiting the assumptions of fast power stroke kinetics and equal load sharing between motors in equivalent states, we reduce the stochastic reaction network to a one-step master equation for the binding and unbinding dynamics (parallel cluster model) and derive the rules for ensemble movement. We find that for constant external load, ensemble dynamics is strongly shaped by the catch bond character of myosin II, which leads to an increase of the fraction of bound motors under load and thus to firm attachment even for small ensembles. This adaptation to load results in a concave force-velocity relation described by a Hill relation. For external load provided by a linear spring, myosin II ensembles dynamically adjust themselves towards an isometric state with constant average position and load. The dynamics of the ensembles is now determined mainly by the distribution of motors over the different kinds of bound states. For increasing stiffness of the external spring, there is a sharp transition beyond which myosin II can no longer perform the power stroke. Slow unbinding from the pre-power-stroke state protects the ensembles against detachment

242

Molecular level all-optical logic with chlorophyll absorption spectrum and polarization sensitivity  

Science.gov (United States)

Chlorophyll is suggested as a suitable medium for realizing optical Boolean logic at the molecular level in view of its wavelength-selective property and polarization sensitivity in the visible region. Spectrophotometric studies are made with solutions of total chlorophyll and chromatographically isolated components, viz. chlorophyll a and b and carotenoids extracted from pumpkin leaves of different maturity stages. The absorption features of matured chlorophyll with two characteristic absorption peaks and one transmission band are molecular properties and independent of concentration. A qualitative explanation of such an absorption property is presented in terms of a ‘particle in a box’ model and the property is employed to simulate two-input optical logic operations. If both of the inputs are either red or blue, absorption is high. If either one is absent and replaced by a wavelength of the transmission band, e.g. green, absorption is low. Assigning these values as 0 s or 1 s, AND and OR operations can be performed. A NOT operation can be simulated with the transmittance instead of the absorbance. Also, the shift in absorbance values for two different polarizations of the same monochromatic light can simulate two logical states with a single wavelength. Cyclic change in absorbance is noted over a rotation of 360° for both red and blue peaks, although the difference is not very large. Red monochromatic light with polarizations apart by 90°, corresponding to maximum and minimum absorption, respectively, may be assigned as the two logical states. The fluorescence emissions for different pigment components are measured at different excitation wavelengths and the effect of fluorescence on the red absorbance is concluded to be negligible.

Raychaudhuri, B.; Bhattacharyya (Bhaumik), S.

2008-06-01

243

Molecular dynamics studies of fluid/oil interfaces for improved oil recovery processes.  

Science.gov (United States)

In our paper, we study the interface wettability, diffusivity, and molecular orientation between crude oil and different fluids for applications in improved oil recovery (IOR) processes through atomistic molecular dynamics (MD). The salt concentration, temperature, and pressure effects on the physical chemistry properties of different interfaces between IOR agents [brine (H(2)O + % NaCl), CO(2), N(2), and CH(4)] and crude oil have been determined. From the interfacial density profiles, an accumulation of aromatic molecules near the interface has been observed. In the case of brine interfaced with crude oil, our calculations indicate an increase in the interfacial tension with increasing pressure and salt concentration, which favors oil displacement. On the other hand, with the other fluids studied (CO(2), N(2), and CH(4)), the interfacial tension decreases with increasing pressure and temperature. With interfacial tension reduction, an increase in fluid diffusivity in the oil phase is observed. We also studied the molecular orientation properties of the hydrocarbon and fluids molecules in the interface region. We perceived that the molecular orientation could be affected by changes in the interfacial tension and diffusivity of the molecules in the interface region with the increased pressure and temperature: pressure (increasing) ? interfacial tension (decreasing) ? diffusion (increasing) ? molecular ordering. From a molecular point of view, the combination of low interfacial tension and high diffusion of molecules in the oil phase gives the CO(2) molecules unique properties as an IOR fluid compared with other fluids studied here. PMID:23163479

de Lara, Lucas S; Michelon, Mateus F; Miranda, Caetano R

2012-12-20

244

Application of nonlinear optical techniques for the investigation of molecular properties and collisional processes  

International Nuclear Information System (INIS)

Molecular collisional processes were studied by using two different nonlinear optical techniques utilizing CO2 lasers. The first study used the techniques of saturation spectroscopy to study the momentum transfer in one direction which occurs when CO2 collides with itself, H2, Ne, NH3, and CH3F. Average CO2 velocity changes determined from these experiments were typically 1/10 the thermal velocity or less. A theoretical model was also developed to explain the experimental observations of CO2 with foreign gas perturbers. Generally good agreement between this model and the data was obtained. The second technique utilized the high-resolution capabilities of Doppler-free two-photon absorption (DFTPA) for the study of molecular properties and collisional processes in the two molecules CH3F and NH3. The first observation of DFTPA in molecular systems using two fixed-frequency CO2 optical fields in combination with molecular Stark tuning is reported. The pressure broadening coefficient and the pressure shift of the O ? ?3 transition were measured; broadening coefficients for the foreign gas perturbers of He and CF3I were determined. A self-broadening coefficient of the O ? 2?2 transition was also measured; foreign gas broadening coefficients for the collision partners H2, D2, He, Ne, and Xe were determined. Spectroscopic information was also obtained about these two molecular systems. (62 figures, 33 tables, 182 references) (U.S.)

245

Atomic-level stress and induced growth of wurtzite zinc oxide using molecular dynamics simulation  

Science.gov (United States)

Molecular dynamics is used to simulate the film growth process of zinc oxide (ZnO) deposited on a ZnO substrate. In the work, the Buckingham-type interatomic potential is modelled to describe the interaction of Zn-O atoms. The effects of incident energy and substrate temperature on the layer coverage function, radial distribution function and residual stress are investigated. Results show that the crystal growth of the deposition film is a symmetric wurtzite lattice along the [0?0?0?1] direction due to charge transformation. Epitaxial-like growth only occurs at very low incident energies, while the intermixing process could start from an incident energy of 3 eV. The average stress of the Zn layer is a compressive stress that is close to zero. However, the average mean biaxial stress and the normal stress of the O layer are -4.49 GPa and -3.07 GPa, respectively. The simulation results are compared with experimental results available in the literature.

Hong, Zheng-Han; Fang, Te-Hua; Hwang, Shun-Fa

2011-12-01

246

On reproduction in red algae: further research needed at the molecular level.  

Science.gov (United States)

Multicellular red algae (Rhodophyta) have some of the most complex life cycles known in living organisms. Economically valuable seaweeds, such as phycocolloid producers, have a triphasic (gametophyte, carposporophyte, and tetrasporophyte) life cycle, not to mention the intricate alternation of generations in the edible "sushi-alga" nori. It is a well-known fact that reproductive processes are controlled by one or more abiotic factor(s), including day length, light quality, temperature, and nutrients. Likewise, endogenous chemical factors such as plant growth regulators have been reported to affect reproductive events in some red seaweeds. Still, in the genomic era and given the high throughput techniques at our disposal, our knowledge about the endogenous molecular machinery lags far behind that of higher plants. Any potential effective control of the reproductive process will entail revisiting most of these results and facts to answer basic biological questions as yet unresolved. Recent results have shed light on the involvement of several genes in red alga reproductive events. In addition, a working species characterized by a simple filamentous architecture, easy cultivation, and accessible genomes may also facilitate our task. PMID:25755663

García-Jiménez, Pilar; Robaina, Rafael R

2015-01-01

247

Atomic-level stress and induced growth of wurtzite zinc oxide using molecular dynamics simulation  

International Nuclear Information System (INIS)

Molecular dynamics is used to simulate the film growth process of zinc oxide (ZnO) deposited on a ZnO substrate. In the work, the Buckingham-type interatomic potential is modelled to describe the interaction of Zn-O atoms. The effects of incident energy and substrate temperature on the layer coverage function, radial distribution function and residual stress are investigated. Results show that the crystal growth of the deposition film is a symmetric wurtzite lattice along the [0?0?0?1] direction due to charge transformation. Epitaxial-like growth only occurs at very low incident energies, while the intermixing process could start from an incident energy of 3 eV. The average stress of the Zn layer is a compressive stress that is close to zero. However, the average mean biaxial stress and the normal stress of the O layer are -4.49 GPa and -3.07 GPa, respectively. The simulation results are compared with experimental results available in the literature. (paper)

248

Processing highly tritiated water desorbed from molecular sieve bed using PERMCAT  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer HTW processed with PERMCAT. Black-Right-Pointing-Pointer Processing of highly tritiated water (HTW). Black-Right-Pointing-Pointer Molecular sieve bed with HTW adsorbed. - Abstract: Tritium handling facilities use molecular sieve beds (MSB) to collect and recover tritiated water. After reaching the capacity limit of the MSB, the water is desorbed and decontaminated in a water detritiation system (WDS). In the case of highly tritiated water (HTW) absorbed into a MSB, an inherent safe option for processing is necessary due to the HTW specific properties. Ideally, HTW should be processed immediately in a continuous mode. With this in consideration, the water desorption process from a zeolite bed was developed and optimized in a dedicated non active facility. The results of this experiments were applied into the regeneration of a MSB previously loaded with HTW containing an activity of 1.9 Multiplication-Sign 10{sup 14} Bq kg{sup -1}. The water was desorbed, by step increasing the temperature bed and fed by helium carrier gas into the PERMCAT for detritiation and tritium recovery. The processed water was collected in a dry MSB downstream of the PERMCAT. These initial studies successfully demonstrate the viability of the process. The obtained results of the preliminary study and the subsequent tests with tritium, will provide useful information for the design of tritium processes relying on MSB, such as the water processing foreseen for the test blanket modules in ITER.

Parracho, A.I. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Demange, D., E-mail: david.demange@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Technical Physics, Tritium Laboratory Karlsruhe, Herrmann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Knipe, S. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Le, L.T.; Simon, K.H.; Welte, S. [Karlsruhe Institute of Technology (KIT), Institute for Technical Physics, Tritium Laboratory Karlsruhe, Herrmann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

2012-08-15

249

Processing highly tritiated water desorbed from molecular sieve bed using PERMCAT  

International Nuclear Information System (INIS)

Highlights: ? HTW processed with PERMCAT. ? Processing of highly tritiated water (HTW). ? Molecular sieve bed with HTW adsorbed. - Abstract: Tritium handling facilities use molecular sieve beds (MSB) to collect and recover tritiated water. After reaching the capacity limit of the MSB, the water is desorbed and decontaminated in a water detritiation system (WDS). In the case of highly tritiated water (HTW) absorbed into a MSB, an inherent safe option for processing is necessary due to the HTW specific properties. Ideally, HTW should be processed immediately in a continuous mode. With this in consideration, the water desorption process from a zeolite bed was developed and optimized in a dedicated non active facility. The results of this experiments were applied into the regeneration of a MSB previously loaded with HTW containing an activity of 1.9 × 1014 Bq kg?1. The water was desorbed, by step increasing the temperature bed and fed by helium carrier gas into the PERMCAT for detritiation and tritium recovery. The processed water was collected in a dry MSB downstream of the PERMCAT. These initial studies successfully demonstrate the viability of the process. The obtained results of the preliminary study and the subsequent tests with tritium, will provide useful information for the design of tritium processes relying on MSB, such as the water processing foreseen for the test blanket modules in ITER.

250

Molecular-level variation affects population growth in a butterfly metapopulation.  

Science.gov (United States)

The dynamics of natural populations are thought to be dominated by demographic and environmental processes with little influence of intraspecific genetic variation and natural selection, apart from inbreeding depression possibly reducing population growth in small populations. Here we analyse hundreds of well-characterised local populations in a large metapopulation of the Glanville fritillary butterfly (Melitaea cinxia), which persists in a balance between stochastic local extinctions and recolonisations in a network of 4,000 discrete habitat patches. We show that the allelic composition of the glycolytic enzyme phosphoglucose isomerase (Pgi) has a significant effect on the growth of local populations, consistent with previously reported effects of allelic variation on flight metabolic performance and fecundity in the Glanville fritillary and Colias butterflies. The strength and the sign of the molecular effect on population growth are sensitive to the ecological context (the area and spatial connectivity of the habitat patches), which affects genotype-specific gene flow and the influence of migration on the dynamics of local populations. The biological significance of the results for Pgi is underscored by lack of any association between population growth and allelic variation at six other loci typed in the same material. In demonstrating, to our knowledge for the first time, that molecular variation in a candidate gene affects population growth, this study challenges the perception that differential performance of individual genotypes, leading to differential fitness, is irrelevant to population dynamics. These results also demonstrate that the spatial configuration of habitat and spatial dynamics of populations contribute to maintenance of Pgi polymorphism in this species. PMID:16620151

Hanski, Ilkka; Saccheri, Ilik

2006-05-01

251

Investigating carbon dynamics in Siberian peat bogs using molecular-level analyses  

Science.gov (United States)

Total hydrolysable carbohydrates, and lignin and cutin acid compounds were analyzed in peat cores collected 56.8 N (SIB04), 58.4 N (SIB06), 63.8 N (G137) and 66.5 N (E113) in the Western Siberian Lowland to investigate vegetation, chemical compositions and the stage of decomposition. Sphagnum mosses dominated peatland vegetation in all four cores. High-resolution molecular analyses revealed rapid vegetation changes on timescales of 50-200 years in the southern cores Sib4 and Sib6. Syringyl and vanillyl (S/V) ratios and cutin acids indicated these vegetation changes were due to varying inputs of angiosperm and gymnosperm and root material. In the G137 and E113 cores lichens briefly replaced sphagnum mosses and vascular plants. Molecular decomposition indicators used in this study tracked the decomposition of different organic constituents of peat organic matter. The carbohydrate decomposition index was sensitive to the polysaccharide component of all peat-forming plants, whereas acid/aldehyde ratios of S and V phenols (Ac/AlS,V) followed the lignin component of vascular plants. Low carbohydrate decomposition indices in peat layers corresponded well with elevated (Ad/Al)S,V ratios. This suggested both classes of biochemicals were simultaneously decomposed, and decomposition processes were associated with extensive total mass loss in these ombrotrophic systems. Selective decomposition or transformation of lignin was observed in the permafrost-influenced northern cores G137 and E113. Both cores exhibited the highest (Ad/Al)S,V ratios, almost four-fold higher than measured in peat-forming plants. The extent of decomposition in the four peat cores did not uniformly increase with age, but showed episodic extensive decomposition events. Variable decomposition events independent of climatic conditions and vegetation shifts highlight the complexity of peatland dynamics.

Kaiser, K.; Benner, R. H.

2013-12-01

252

Increased retinoic acid levels through ablation of Cyp26b1 determine the processes of embryonic skin barrier formation and peridermal development  

OpenAIRE

The process by which the periderm transitions to stratified epidermis with the establishment of the skin barrier is unknown. Understanding the cellular and molecular processes involved is crucial for the treatment of human pathologies, where abnormal skin development and barrier dysfunction are associated with hypothermia and perinatal dehydration. For the first time, we demonstrate that retinoic acid (RA) levels are important for periderm desquamation, embryonic skin differentiation and barr...

Okano, Junko; Lichti, Ulrike; Mamiya, Satoru; Aronova, Maria; Zhang, Guofeng; Yuspa, Stuart H.; Hamada, Hiroshi; Sakai, Yasuo; Morasso, Maria I.

2012-01-01

253

Level of Detail and Level of Development: Commissioning processes and Information Modelling  

Directory of Open Access Journals (Sweden)

Full Text Available The essence of Information Modelling in the Construction Industry lies in the methods of evolution of the information content through the lifecycle of the commission and the work. Such progress in the levels of development of the model is profoundly different from normal progress as it is strongly affected by the goals of whoever is managing the Information Model itself. The subjects that appear to benefit most from this seem to be governments, delegated project contractors, authorities or promoters and finally and in particular, lenders.

Angelo Ciribini

2013-10-01

254

Anthropogenic and Climate Influences on Biogeochemical Dynamics and Molecular-Level Speciation of Soil Sulfur  

Energy Technology Data Exchange (ETDEWEB)

The soil environment is a primary component of the global biogeochemical sulfur (S) cycle, acting as a source and sink of various S species and mediating oxidation state changes. However, ecological significance of the various S forms and the impacts of human intervention and climate on the amount and structural composition of these compounds are still poorly understood. We investigated the long-term influences of anthropogenically mediated transitions from natural to managed ecosystems on molecular-level speciation, biogeochemical dynamics, and the apparent temperature sensitivity of S moieties in temperate, subtropical, and tropical environments with mean annual temperature (MAT) ranging from 5C to 21C, using elemental analysis and X-ray absorption near-edge structure (XANES) spectroscopy. Land-use and land-cover changes led to the depletion of total soil S in all three ecoregions over a period of up to 103 years. The largest decline occurred from tropical forest agroecosystems (67% Kakamega and 76% Nandi, Kenya), compared to losses from temperate (36% at Lethbridge, Canada, and 40% at Pendleton, USA) and subtropical (48% at South Africa) grassland agroecosystems. The total S losses correlated significantly with MAT. Anthropogenic interventions profoundly altered the molecular-level composition and resulted in an apparent shift in oxidation states of organic S from native ecosystems composed primarily of S moieties in intermediate and highly reduced oxidation states toward managed agroecosystems dominated by organic S rich in strongly oxidized functionalities. The most prominent change occurred in thiols and sulfides, the proportion of which decreased by 46% (Lethbridge) and 57% (Pendleton) in temperate agroecosystems, by 46% in subtropical agroecosystems, and by 79% (Nandi) and 81% (Kakamega) in tropical agroecosystems. The proportion of organic S directly linked to O increased by 81%, 168%, 40%, 92%, and 85%, respectively. Among the various organic S functionalities, thiols and sulfides seem to have higher apparent temperature sensitivity, and thus these organic S moieties may become prone to losses due to land-use changes, even from the cooler regions of the world if MAT of these regions rise in the future.

Solomon, D.; Lehmann, J; Kinyangi, J; Pell, A; Theis , J; Riha , S; Ngoze, S; Amelung, W; du Preez, C; et. al.

2009-01-01

255

Methods of glioma sample processing for molecular diagnosis for the glioma tissue bank project.  

Science.gov (United States)

Genome-wide sequencing in glioma samples provides comprehensive insights into oncogenesis and malignant transformation. Several distinct biomarkers have been proven to have clinical significance and are being widely applied in routine clinical practice. Standard sample processing lays the foundation for successful molecular testing. In this study, we found intraoperative neuronavigation ensured higher tumor purity during sample collection, and an automated device helped improve DNA quality and increased yields. These two technologies are beneficial for glioma tissue bank construction and provide for accurate molecular testing during routine clinical practice. PMID:25686045

Shi, Zhi-Feng; Aibaidula, Abudumijiti; Tang, Qi-Sheng; Shen, Yi-Wen; Chen, Hong; Wu, Jin-Song; Qin, Zhi-Yong; Zhu, Jian-Hong; Mao, Ying; Zhou, Liang-Fu

2015-02-01

256

Graphene hydrogenation by molecular hydrogen in the process of graphene oxide thermal reduction  

Science.gov (United States)

Thermal reduction in molecular hydrogen of the graphene oxide films has been studied by X-ray photoelectron spectroscopy using synchrotron radiation. The restoration process was revealed to be accompanied by hydrogenation due to collisionally induced interaction of molecular hydrogen with carbon atoms. One side hydrogenated graphene films consisting of 20 ?m one monolayer flakes were fabricated on SiO2/Si surface with hydrogen concentration as far as 40 at. %, at which the 0.3 eV bandgap opening was observed. It was shown that both H-coverage and bandgap width of the films can be controlled by varying the temperature of the heat treatment.

Mikoushkin, V. M.; Nikonov, S. Yu.; Dideykin, A. T.; Vul', A. Ya.; Sakseev, D. A.; Baidakova, M. V.; Vilkov, O. Yu.; Nelyubov, A. V.

2013-02-01

257

Removal of higher molecular weight organic compounds by the granular activated carbon adsorption unit process.  

Science.gov (United States)

The granular activated carbon adsorption unit process in drinking water treatment typically removes purgeable organic compounds for time periods on the order of a few weeks. Experimental evidence indicates that less volatile compounds of generally higher molecular weight than the purgeable fraction, but still detectable by gas chromatography, are efficiently removed for longer periods. Field data substantiate this. Explanatory mechanisms may include stronger adsorption affinities or biodegradation. Non-gas chromatographable, higher molecular weight materials such as humic acids, as measured by Total Organic Carbon (TOC) or trihalomethane formation potential, revert to lower removal efficiencies. Biodegradation may be responsible for a continued long term removal of a fraction of these materials. PMID:3694484

Stevens, A A; Seeger, D R; DeMarco, J; Moore, L

1987-01-01

258

Ecotoxicity of triphenyltin on the marine copepod Tigriopus japonicus at various biological organisations: from molecular to population-level effects.  

Science.gov (United States)

Triphenyltin compounds (TPTs), as effective biocides for different industrial and agricultural purposes, have been detected in coastal marine environments worldwide, in particular in Asian countries. However, little is known about their toxicity to marine organisms. This study comprehensively investigated the molecular, individual and population responses of the marine copepod, Tigriopus japonicus upon waterborne exposure to TPT chloride (TPTCl). Our results indicated that TPTCl was highly toxic to adult T. japonicus, with a 96-h LC50 concentration at 6.3 ?g/L. As shown in a chronic full life-cycle test, T. japonicus exposed to 1.0 ?g/L TPTCl exhibited a delay in development and a significant reduction of population growth, in terms of the intrinsic rate of increase (r m ). Based on the negative relationship between the r m and exposure concentration, a critical effect concentration was estimated at 1.6 ?g/L TPTCl; at or above which population extinction could occur. At 0.1 ?g/L TPTCl or above, the sex ratio of the second generation of the copepod was significantly altered and changed to a male-biased population. At molecular level, the inhibition of the transcriptional expression of glutathione S-transferase related genes might lead to dysfunction of detoxification, and the inhibition of retinoid X receptor mRNA expression implied an interruption of the growth and moulting process in T. japonicus. As the only gene that observed up-regulated in this study, the expression of heat shock protein 70 (hsp70) increased in a concentration-dependent manner, indicating its function in protecting the copepod from TPT-mediated oxidative stress. The study advances our understanding on the ecotoxicity of TPT, and provides some initial data on its toxic mechanisms in small crustaceans like copepods. PMID:24981692

Yi, Andy Xianliang; Han, Jeonghoon; Lee, Jae-Seong; Leung, Kenneth M Y

2014-09-01

259

La modificación covalente de proteínas. Un nivel cualitativamente superior de la información molecular / Covalent Modifications of Proteins. A qualitative higher level of molecular information  

Scientific Electronic Library Online (English)

Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish Introducción: La información molecular es una propiedad principal de las biomacromoléculas, especialmente proteínas y ácidos nucleicos, que permite la realización de funciones con un alto grado de especificidad. Ella deriva de la variedad en los componentes de las macromoléculas. Objetivo: Demostrar [...] que la modificación covalente de proteínas constituye un nivel nuevo y superior de información molecular. Método: Se analizaron artículos de los últimos 5 años, publicados en revistas nacionales y de circulación internacional, disponibles en las bases de datos HINARI, PubMed y Perii y localizados mediante el sitio www.infomed.sld.cu. Desarrollo: Se exponen los mecanismos y características principales del proceso y posteriormente algunos de los efectos principales de la modificación covalente sobre las funciones y propiedades de las proteínas. Conclusiones: La modificación covalente es un mecanismo que amplía el campo de acción de las proteínas permitiendo un rápido cambio en sus propiedades funcionales y, por lo tanto, constituye un nivel nuevo y cualitativamente superior de información molecular. Abstract in english Introduction: Molecular information is an essential property of biomacromolecules, especially proteins and nucleic acids. This property allows carrying out specific functions. It derives from variability of macromolecules components. Objetive: To prove that covalent modification of proteins represen [...] ts a new and higher level of molecular information. Method: Papers published during the last five years in national and international journals were analyzed. These articles are available in HINARI, PubMed, and Perii databases and were localized through www.infomed.sld.cu. Main text: First, the mechanism and features of covalent modifications of protein are presented. Next, the principal effects on protein functions and properties are analyzed. Conclusions: We conclude that covalent modification of proteins represents a new and higher level of molecular information.

Rolando A, Hernández Fernández.

2014-02-01

260

GFZ GRACE Level-2 Processing Standards Document for Level-2 Product Release 0005 : revised edition, January 2013  

OpenAIRE

This document serves as a record of the processing standards, models & parameters adopted for the generation of monthly and weekly (aligned to GPS weeks) Level-2 gravity field data products by the GRACE Science Data System component at the GFZ German Research Centre for Geosciences.

Christoph Dahle; Frank Flechtner; Christian Gruber; Daniel König; Rolf König; Grzegorz Michalak; Karl-Hans Neumayer

2013-01-01

261

A Better Insight Into IT Contribution by Process Level Structure : A Case Study in Royal Greenland  

DEFF Research Database (Denmark)

Creation of IT business value through its impact on value chain processes made the objective of this research to compare and differentiate IT role at both process and firm levels. A discussion about IT’s impact at both levels are made through previous theoretical and empirical studies. The discussion is supported by an introduction to the case of study in Royal Greenland. The contribution of this paper is the results of the discussions and the case study reaching to the point that IT supporting influences are better understood and observed at process levels rather than firm output level.

Shahim, Nazli; MØller, Charles

2013-01-01

262

Assessment of radiation-induced damage to DNA at the molecular level by mass spectrometry  

International Nuclear Information System (INIS)

Full text: Ionizing radiation-induced damage to DNA in living cells may lead to biological consequences such as mutation, carcinogenesis or cell death. Free radicals generated from water by ionising radiation, especially OH radicals produce a large number of base and sugar derived stable products in DNA as well as DNA-protein complexes. Repair of these structural modifications is essential to maintain the genomic integrity to prevent long term effects of radiation. Understanding the cellular repair of ionizing radiation-induced damage to DNA in cell obviously depends upon the knowledge of the chemical nature of DNA lesions and their quantities at the molecular level. Several types of assays are known to measure the yields of radiation-induced purine and pyrimidine products in DNA which include chromatographic, immunochemical or biochemical technologies. However, these procedures are capable of assaying only a very limited number of modified DNA products and lack sensitivity and selectivity. We have developed sensitive and specific gas chromatography-mass spectrometry methods (GC/MS) for chemical identification and estimation of modifications in DNA at physiologically relevant doses. This presentation will focus primarily on the sampling, instrumentation, applications and limitations of GC/MS procedures in assaying radiation-induced damage and repair to DNA

263

Elucidating redox-level dispersion and local dielectric effects within electroactive molecular films.  

Science.gov (United States)

The electron exchange between a redox-active molecular film and its underlying electrode can be cleanly tracked, in a frequency-resolved manner, through associated capacitive charging. If acquired data is treated with a classical (non quantum) model, mathematically equivalent to a Nernst distribution for one redox energy level, redox site coverage is both underestimated and environmentally variable. This physically unrealistic model fails to account for the energetic dispersion intrinsically related to the quantized characteristics of coupled redox and electrode states. If one maps this redox capacitive charging as a function of electrode potential one not only reproduces observations made by standard electroanalytical methods but additionally and directly resolves the spread of redox state energies the electrode is communicating with. In treating a population of surface-confined redox states as constituting a density of states, these analyses further resolve the effects of electrolyte dielectric on energetic spread in accordance with the electron-transfer models proposed by Marcus and others. These observations additionally underpin a directly (spectrally) resolved dispersion in electron-transfer kinetics. PMID:24392706

Bueno, Paulo R; Davis, Jason J

2014-02-18

264

Molecular analyses reveal high levels of eukaryotic richness associated with enigmatic deep-sea protists (Komokiacea)  

DEFF Research Database (Denmark)

Komokiaceans are testate agglutinated protists, extremely diverse and abundant in the deep sea. About 40 species are described and share the same main morpholog- ical feature: a test consisting of narrow branching tubules forming a complex system. In some species, the interstices between the tubules are filled by sediment, creating a mudball structure. Because of their unusual and sometimes featureless appearance, komokiaceans were frequently ignored or overlooked until they formal description in 1977. The most recent taxonomy places the Komokiacea within the Foraminifera based on general morphological features. To examine their taxonomic position at the molecular level, we analysed the SSU rDNA sequences of two species, Normanina conferta and Septuma ocotillo, obtained either with specific foraminiferal or universal eukaryotic primers. Many different sequences resulted from this investigation but none of them could clearly be attributed to komokiaceans. Although our study failed to confirm univocally that Komokiacea are foraminiferans, it revealed a huge eukaryotic richness associated with these organisms, comparable with the richness in the overall surrounding sediment. These observations suggest strongly that komokiaceans, and probably many other large testate protists, provide a habitat structure for a large spectrum of eukaryotes, significantly contributing to maintaining the biodiversity of micro- and meiofaunal communities in the deep sea.

Lecroq, Beatrice; Gooday, Andrew John

2009-01-01

265

Insights into the uranium(VI) speciation with Pseudomonas fluorescens on a molecular level.  

Science.gov (United States)

Microorganisms have great potential to bind and thus transport actinides in the environment. Thus microbes indigenous to designated nuclear waste disposal sites have to be investigated regarding their interaction mechanisms with soluble actinyl ions when assessing the safety of a planned repository. This paper presents results on the pH-dependent sorption of U(VI) onto Pseudomonas fluorescens isolated from the granitic rock aquifers at Äspö Hard Rock Laboratory, Sweden. To characterize the U(VI) interaction on a molecular level, potentiometric titration in combination with time-resolved laser-induced fluorescence spectroscopy (TRLFS) were applied. This paper as a result is one of the very few sources which provide stability constants of U(VI) complexed by cell surface functional groups. In addition the bacteria-mediated liberation of inorganic phosphate in dependence on [U(VI)] at different pHs was studied to judge the influence of phosphate release on U(VI) mobilization. The results demonstrate that in the acidic pH range U(VI) is bound by the cells mainly via protonated phosphoryl and carboxylic sites. The complexation by carboxylic groups can be observed over a wide pH range up to around pH 7. At neutral pH fully deprotonated phosphoryl groups are mainly responsible for U(VI) binding. U(VI) can be bound by P. fluorescens with relatively high thermodynamic stability. PMID:23007661

Lütke, Laura; Moll, Henry; Bernhard, Gert

2012-11-21

266

Long-term management of high-level defense wastes at the Idaho Chemical Processing Plant  

International Nuclear Information System (INIS)

Plans and technology for the long-term management of existing and future high-level defense wastes generated at the Idaho Chemical Processing Plant are discussed. Current high-level waste management is also reviewed to show the continuity between present and future high-level waste management. 1 ref

267

Process evaluation of an open architecture real-time molecular laboratory platform.  

Science.gov (United States)

The needs of molecular diagnostic laboratories that perform both Food and Drug Administration-cleared as well as laboratory-developed tests are usually not met on a single analytical platform. Furthermore, little information is available about the direct impact of molecular automation on labor costs and efficiency in clinical laboratories. We performed a process impact analysis from time and motion studies of a novel molecular diagnostic robotic system designed to automate sample preparation, extraction, and analysis. All 27 preanalytical tasks were quantified for the amount of time spent preparing 24 specimens for analysis. These steps were completed in 899 s (14 min, 59 s) followed by 7887 s (131 min, 27 s) of instrument operation independent of operator control (walk-away time). Postanalytical results evaluation required 1 min per specimen. The instrument automatically extracted the nucleic acid from the specimen, added the eluted DNA to the amplification reagents, and performed the analysis. Only 12% of the total instrument operations required relatively unskilled human labor. Thus, the availability of automated molecular diagnostic instruments will facilitate the expansion of molecular testing in the clinical laboratory because they reduce operator costs with respect to time and complexity of the tasks they are asked to perform. PMID:24811476

Felder, Robin A; Jackson, Keith D; Walter, Adam M

2014-10-01

268

Symmetry Breaking in NMR Spectroscopy: The Elucidation of Hidden Molecular Rearrangement Processes  

Directory of Open Access Journals (Sweden)

Full Text Available Variable-temperature NMR spectroscopy is probably the most convenient and sensitive technique to monitor changes in molecular structure in solution. Rearrangements that are rapid on the NMR time-scale exhibit simplified spectra, whereby non-equivalent nuclear environments yield time-averaged resonances. At lower temperatures, when the rate of exchange is sufficiently reduced, these degeneracies are split and the underlying “static” molecular symmetry, as seen by X-ray crystallography, becomes apparent. Frequently, however, such rearrangement processes are hidden, even when they become slow on the NMR time-scale, because the molecular point group remains unchanged. Judicious symmetry breaking, such as by substitution of a molecular fragment by a similar, but not identical moiety, or by the incorporation of potentially diastereotopic (chemically non-equivalent nuclei, allows the elucidation of the kinetics and energetics of such processes. Examples are chosen that include a wide range of rotations, migrations and other rearrangements in organic, inorganic and organometallic chemistry.

Michael J. McGlinchey

2014-08-01

269

A quantum mechanical model of the Bloch NMR flow equations for electron dynamics in fluids at the molecular level  

International Nuclear Information System (INIS)

Understanding of processes such as carrier mobility, electron transfer reactions, chemical reactions in fluids, electron solvation in fluids and electron attachment and localization in clusters relies crucially on the understanding of electron dynamics in fluids at the molecular level. Because of its very small mass, an electron is a quantum object and some of its properties such as diffusion coefficient of a solvated electron in water can be explained only by resorting to quantum mechanical formulation. In this study, we have solved the Bloch NMR flow equations to describe the evolution of the wavelike properties and find the wave functions which can be useful to solve a particular fluid flow problem quantum mechanically. Based on the uncertainty principle, a wave packet is assumed to initially describe the fluid particle (electron) under study. Then, when the particle encounters a force (so its potential energy is no longer zero), the force modifies the wave packet. Finding such propagation techniques, and applying them appropriately can provide useful techniques to find solutions to biological, medical and physical problems which otherwise could not be easily solved

270

Molecular Basis of a Million-Fold Affinity Maturation Process in a Protein-Protein Interaction  

Energy Technology Data Exchange (ETDEWEB)

Protein engineering is becoming increasingly important for pharmaceutical applications where controlling the specificity and affinity of engineered proteins is required to create targeted protein therapeutics. Affinity increases of several thousand-fold are now routine for a variety of protein engineering approaches, and the structural and energetic bases of affinity maturation have been investigated in a number of such cases. Previously, a 3-million-fold affinity maturation process was achieved in a protein-protein interaction composed of a variant T-cell receptor fragment and a bacterial superantigen. Here, we present the molecular basis of this affinity increase. Using X-ray crystallography, shotgun reversion/replacement scanning mutagenesis, and computational analysis, we describe, in molecular detail, a process by which extrainterfacial regions of a protein complex can be rationally manipulated to significantly improve protein engineering outcomes.

D Bonsor; S Postel; B Pierce; N Wang; P Zhu; R Buonpane; Z Weng; D Kranz; E Sundberg

2011-12-31

271

Atomic and molecular processes generated by linearly polarized few-cycle laser pulses  

Science.gov (United States)

S-matrix theory is used to analyze different atomic and molecular processes in a linearly polarized few-cycle laser field. The energy spectra of high-order above-threshold ionization (HATI) are presented. Electron-atom potential scattering assisted by a few-cycle laser pulse is also analyzed. It is shown that the plateau structures in the energy spectra of the electron-atom potential scattering are dependent on the carrier-envelope phase (CEP) of the laser pulse, so that the cutoff positions of the plateaus can be controlled by changing the CEP. Regarding our analysis of the molecular HATI process, the angle-resolved spectra, obtained by different theoretical approaches, are also presented.

Busuladži?, M.; ?erki?, A.; Odžak, S.; Gazibegovi?-Busuladži?, A.; Hasovi?, E.; Habibovi?, D.; Miloševi?, D. B.

2014-09-01

272

Biologia molecular do processo de infecção por Agrobacterium spp. / Molecular biology of the infection process by Agrobacterium spp.  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Agrobacterium tumefaciens é o agente causal da galha-da-coroa, doença que afeta a maioria das plantas dicotiledôneas e caracteriza-se pelo crescimento de tumores na junção entre o caule e a raiz (coroa). A formação desses tumores é o resultado de um processo natural de transferência de genes de Agro [...] bacterium spp. para o genoma da planta infetada. Esses genes estão contidos em um plasmídio de alto peso molecular (120 a 250 kb), denominado Ti ("tumor inducing"), presente em todas as linhagens patogênicas de Agrobacterium spp. Duas regiões do plasmídio Ti estão diretamente envolvidas na indução do tumor: a região-T, que corresponde ao segmento de DNA transferido para a célula vegetal, e a região de virulência (região vir), que contém genes envolvidos na síntese de proteínas responsáveis pelo processo de transferência da região-T. Esta região, uma vez transferida e integrada no genoma da célula vegetal, passa a ser denominada de T-DNA ("transferred DNA"). Os genes presentes no T-DNA codificam enzimas envolvidas na via de biossíntese de reguladores de crescimento, auxinas e citocininas. A síntese desses reguladores pelas células transformadas causa um desbalanço hormonal, levando à formação do tumor no local da infecção. Outro grupo de genes presentes no T-DNA codifica enzimas responsáveis pela síntese de opinas, que são catabolisadas especificamente pela bactéria colonizadora, como fonte de nutrientes. O conhecimento preliminar das bases moleculares envolvidas no processo de infecção de uma planta hospedeira por Agrobacterium spp., permitiu a utilização desta bactéria como vetor natural de transformação genética de plantas. Abstract in english Agrobacterium tumefaciens is the causal agent of crown gall disease that affects most dicotyledonous plants and is characterized by growth of tumors in the region between the plant stem and root (crown). The development of tumors is the result of a natural transfer process of Agrobacterium spp. gene [...] s to the genome of the infected plant. These genes are found on a high molecular weight plasmid denominated Ti (tumor inducing), present in all pathogenic Agrobacterium spp. strains. Two Ti plasmid regions are directly involved in tumor induction. The T-region, which corresponds to the segment of transferred DNA to the plant cells, and the virulence (vir) region, which contains genes involved in the synthesis of proteins required for T-region transfer. This region, when transferred and integrated to the plant cell genome, is called T-DNA (transferred DNA). The genes present in T-DNA encode enzymes involved in the biosynthesis of plant growth regulators, auxin and cytokinin. The synthesis of these regulators by transformed cells results in a hormonal inbalance, leading to the development of tumors where the infection took place. Another group of genes present in T-DNA encodes enzymes required for opine synthesis, which are specifically catabolised by the colonizing bacterium as the source of nutrients. Preliminary knowledge of the molecular basis involved in the infection process of the host plant by Agrobacterium spp. allowed the use of this bacterium as a natural vector for plant genetic transformation.

Gisele M. de, Andrade; Laudete M., Sartoretto; Ana C. M., Brasileiro.

2003-10-01

273

Biologia molecular do processo de infecção por Agrobacterium spp. Molecular biology of the infection process by Agrobacterium spp.  

Directory of Open Access Journals (Sweden)

Full Text Available Agrobacterium tumefaciens é o agente causal da galha-da-coroa, doença que afeta a maioria das plantas dicotiledôneas e caracteriza-se pelo crescimento de tumores na junção entre o caule e a raiz (coroa. A formação desses tumores é o resultado de um processo natural de transferência de genes de Agrobacterium spp. para o genoma da planta infetada. Esses genes estão contidos em um plasmídio de alto peso molecular (120 a 250 kb, denominado Ti ("tumor inducing", presente em todas as linhagens patogênicas de Agrobacterium spp. Duas regiões do plasmídio Ti estão diretamente envolvidas na indução do tumor: a região-T, que corresponde ao segmento de DNA transferido para a célula vegetal, e a região de virulência (região vir, que contém genes envolvidos na síntese de proteínas responsáveis pelo processo de transferência da região-T. Esta região, uma vez transferida e integrada no genoma da célula vegetal, passa a ser denominada de T-DNA ("transferred DNA". Os genes presentes no T-DNA codificam enzimas envolvidas na via de biossíntese de reguladores de crescimento, auxinas e citocininas. A síntese desses reguladores pelas células transformadas causa um desbalanço hormonal, levando à formação do tumor no local da infecção. Outro grupo de genes presentes no T-DNA codifica enzimas responsáveis pela síntese de opinas, que são catabolisadas especificamente pela bactéria colonizadora, como fonte de nutrientes. O conhecimento preliminar das bases moleculares envolvidas no processo de infecção de uma planta hospedeira por Agrobacterium spp., permitiu a utilização desta bactéria como vetor natural de transformação genética de plantas.Agrobacterium tumefaciens is the causal agent of crown gall disease that affects most dicotyledonous plants and is characterized by growth of tumors in the region between the plant stem and root (crown. The development of tumors is the result of a natural transfer process of Agrobacterium spp. genes to the genome of the infected plant. These genes are found on a high molecular weight plasmid denominated Ti (tumor inducing, present in all pathogenic Agrobacterium spp. strains. Two Ti plasmid regions are directly involved in tumor induction. The T-region, which corresponds to the segment of transferred DNA to the plant cells, and the virulence (vir region, which contains genes involved in the synthesis of proteins required for T-region transfer. This region, when transferred and integrated to the plant cell genome, is called T-DNA (transferred DNA. The genes present in T-DNA encode enzymes involved in the biosynthesis of plant growth regulators, auxin and cytokinin. The synthesis of these regulators by transformed cells results in a hormonal inbalance, leading to the development of tumors where the infection took place. Another group of genes present in T-DNA encodes enzymes required for opine synthesis, which are specifically catabolised by the colonizing bacterium as the source of nutrients. Preliminary knowledge of the molecular basis involved in the infection process of the host plant by Agrobacterium spp. allowed the use of this bacterium as a natural vector for plant genetic transformation.

Gisele M. de Andrade

2003-10-01

274

All-dry processible and PAG-attached molecular glasses for improved lithographic performance  

Science.gov (United States)

As the semiconductor industry moves forward, resolution limits are being pushed to the sub-30 nm regime. In order to meet these demands, radical new resist design and processes must be explored. We have developed a molecular glass system for all-dry processing conditions. Physical vapor deposition (PVD) has been used for film formation onto silicon wafers. PVD deposits a uniform film of controlled thickness free from impurities that are often introduced by casting solvents used in traditional spin coating methods. Thermal development is used as an alternative to processing in solvents in order to prevent resist swelling and pattern collapse by capillary forces. The deposited molecule is designed to crosslink upon E-beam irradiation without additives, and therefore form a homogeneous, single component film. PAG-attached molecular glasses have been synthesized in order to promote film homogeneity as well. By tethering PAG directly to the molecular glass core, issues such as PAG aggregation can be remedied. Acid migration, which increases blur and LER, can also be hindered.

Krysak, Marie; Kolb, Tristan; Neuber, Christian; Schmidt, Hans-Werner; Ober, Christopher K.

2010-04-01

275

Homology modeling, molecular dynamics and atomic level interaction study of snake venom 5' nucleotidase.  

Science.gov (United States)

5' Nucleotidase (5' NUC) is a ubiquitously distributed enzyme known to be present in snake venoms (SV) that is responsible primarily for causing dysregulation of physiological homeostasis in humans by inducing anticoagulant effects and by inhibiting platelet aggregation. It is also known to act synergistically with other toxins to exert a more pronounced anti-coagulant effect during envenomation. Its structural and functional role is not yet ascertained clearly. The 3D structure of snake venom 5' nucleotidase (SV-5' NUC) is not yet known and was predicted by us for the first time using a comparative homology modeling approach using Demansia vestigiata protein sequence. The accuracy and stability of the predicted SV-5' NUC structure were validated using several computational approaches. Key interactions of SV-5' NUC were studied using experimental studies/molecular docking analysis of the inhibitors vanillin, vanillic acid and maltol. All these inhibitors were found to dock favorably following pharmacologically relevant absorption, distribution, metabolism and excretion (ADME) profiles. Further, atomic level docking interaction studies using inhibitors of the SV-5' NUC active site revealed amino acid residues Y65 and T72 as important for inhibitor-(SV-5' NUC) interactions. Our in silico analysis is in good agreement with experimental inhibition results of SV-5' NUC with vanillin, vanillic acid and maltol. The present study should therefore play a guiding role in the experimental design of new SV-5' NUC inhibitors for snake bite management. We also identified a few pharmacophoric features essential for SV-5' NUC inhibitory activity that can be utilized further for the discovery of putative anti-venom agents of therapeutic value for snake bite management. PMID:24567162

Arafat, A Syed Yasir; Arun, A; Ilamathi, M; Asha, J; Sivashankari, P R; D'Souza, Cletus J M; Sivaramakrishnan, V; Dhananjaya, B L

2014-03-01

276

Molecular evolution of multiple-level control of heme biosynthesis pathway in animal kingdom.  

Science.gov (United States)

Adaptation of enzymes in a metabolic pathway can occur not only through changes in amino acid sequences but also through variations in transcriptional activation, mRNA splicing and mRNA translation. The heme biosynthesis pathway, a linear pathway comprised of eight consecutive enzymes in animals, provides researchers with ample information for multiple types of evolutionary analyses performed with respect to the position of each enzyme in the pathway. Through bioinformatics analysis, we found that the protein-coding sequences of all enzymes in this pathway are under strong purifying selection, from cnidarians to mammals. However, loose evolutionary constraints are observed for enzymes in which self-catalysis occurs. Through comparative genomics, we found that in animals, the first intron of the enzyme-encoding genes has been co-opted for transcriptional activation of the genes in this pathway. Organisms sense the cellular content of iron, and through iron-responsive elements in the 5' untranslated regions of mRNAs and the intron-exon boundary regions of pathway genes, translational inhibition and exon choice in enzymes may be enabled, respectively. Pathway product (heme)-mediated negative feedback control can affect the transport of pathway enzymes into the mitochondria as well as the ubiquitin-mediated stability of enzymes. Remarkably, the positions of these controls on pathway activity are not ubiquitous but are biased towards the enzymes in the upstream portion of the pathway. We revealed that multiple-level controls on the activity of the heme biosynthesis pathway depend on the linear depth of the enzymes in the pathway, indicating a new strategy for discovering the molecular constraints that shape the evolution of a metabolic pathway. PMID:24489775

Tzou, Wen-Shyong; Chu, Ying; Lin, Tzung-Yi; Hu, Chin-Hwa; Pai, Tun-Wen; Liu, Hsin-Fu; Lin, Han-Jia; Cases, Ildeofonso; Rojas, Ana; Sanchez, Mayka; You, Zong-Ye; Hsu, Ming-Wei

2014-01-01

277

Embedding Knowledge Processes to Maintain Service Levels and Efficiency in a Growing Software Service Firm:  

OpenAIRE

Software service firms are challenged to maintain high service levels and to innovate at the same time. Therefore, valuable human resources need often to be balanced between innovation and operations related activities. In this paper we describe how such as a firm deals with these issues by embedding their knowledge processes into their business processes. The advantage of embedding knowledge processes is that knowledge workers are more likely to adopt these processes in their daily support a...

Oostdam, M.; Verburg, R. M.; Lobbezoo, M.

2013-01-01

278

Method and device for solidifying high level liquid wastes from a re-processing plant  

International Nuclear Information System (INIS)

Purpose: To decrease the production of chlorides and reduce the amount of secondary liquid wastes by using low concentration nitric acid at a low radioactive level obtained from a condensator as scrubber feeding liquid. Constitution: In a solidification device for high level liquid wastes from a re-processing plant in which off-gases resulted from solidification of high level liquid wastes from a re-processing plant are cleaned with gas cleaning liquids and returned while being concentrated to a high level liquid waste solidification stage, the off gases produced in the concentration stage are condensed and the condensed liquids are fed as the gas cleaning liquids. (Aizawa, K.)

279

Molecular dynamics simulations of the relaxation processes in the condensed matter on GPUs  

Science.gov (United States)

We report on simulation technique and benchmarks for molecular dynamics simulations of the relaxation processes in solids and liquids using the graphics processing units (GPUs). The implementation of a many-body potential such as the embedded atom method (EAM) on GPU is discussed. The benchmarks obtained by LAMMPS and HOOMD packages for simple Lennard-Jones liquids and metals using EAM potentials are presented for both Intel CPUs and Nvidia GPUs. As an example the crystallization rate of the supercooled Al melt is computed.

Morozov, I. V.; Kazennov, A. M.; Bystryi, R. G.; Norman, G. E.; Pisarev, V. V.; Stegailov, V. V.

2011-09-01

280

Sustained high levels of neuroprotective, high molecular weight, phosphorylated tau in the longest-lived rodent.  

Science.gov (United States)

Tau protein is primarily expressed in neuronal axons and modulates microtubule stability. Tau phosphorylation, aggregation, and subcellular mislocalization coincide with neurodegeneration in numerous diseases, including Alzheimer's disease (AD). During AD pathogenesis, tau misprocessing accompanies Aß accumulation; however, AD animal models, despite elevated Aß, fail to develop tauopathy. To assess whether lack of tau pathology is linked to short life span common to most AD models, we examined tau processing in extraordinarily long-lived, mouse-sized naked mole-rats (NMRs; approximately 32 years), which express appreciable levels of Aß throughout life. We found that NMRs, like other mammals, display highest tau phosphorylation during brain development. Although tau phosphorylation decreases with aging, unexpectedly adult NMRs have higher levels than transgenic mice overexpressing mutant human tau. However, in sharp contrast with the somatodendritic accumulation of misprocessed tau in the transgenic mice, NMRs maintain axonal tau localization. Intriguingly, the adult NMR tau protein is 88 kDa, much larger than 45-68 kDa tau expressed in other mammals. We propose that this 88 kDa tau protein may offer exceptional microtubule stability and neuroprotection against lifelong, elevated Aß. PMID:25576082

Orr, Miranda E; Garbarino, Valentina R; Salinas, Angelica; Buffenstein, Rochelle

2015-03-01

281

The effect of molecular relaxation processes in air on the rise time of sonic booms  

Science.gov (United States)

A theory is developed to explain the effect of molecular relaxation processes on the rise time of sonic booms. To determine the rise time of sonic booms, both O2 and N2 relaxation processes must be included. The N2 relaxation process delays the shock pressure reaching the maximum pressure, and the O2 relaxation process causes a shock profile to have a gentle slope. The N2 relaxation controls the lower part of overpressure; the O2 relaxation controls the higher part. The constant rise time curves show that the rise times increase as the overpressures and humidity decrease. The present approach gives longer rise times than those acquired by Bass et al. for given shock overpressures.

Kang, Jongmin; Pierce, Allan D.

1990-01-01

282

Insights into the molecular level composition, sources, and formation mechanisms of dissolved organic matter in aerosols and precipitation  

Science.gov (United States)

Atmospheric aerosols scatter and absorb light influencing the global radiation budget and climate, and are associated with adverse effects on human health. Precipitation is an important removal mechanism for atmospheric dissolved organic matter (DOM), and a potentially important input for receiving ecosystems. However, the sources, formation, and composition of atmospheric DOM in aerosols and precipitation are not well understood. This dissertation investigates the composition and formation mechanisms of secondary organic aerosol (SOA) formed through cloud processing reactions, elucidates the composition and sources of DOM in rainwater, and provides links connecting the two. Photochemical batch aqueous-phase reactions of organics with both biogenic and anthropogenic sources (i.e., methylglyoxal, pyruvic acid) and OH radical were performed to simulate cloud processing. The composition of products formed through cloud processing experiments and rainwater collected in New Jersey, USA was investigated using a combination of electrospray ionization mass spectrometry techniques, including ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry. This dissertation has resulted in the first evidence that oligomers form through cloud processing reactions, the first detailed chemical mechanism of aqueous phase oligomerization, the first identification of oligomers, organosulfates, and nitrooxy organosulfates in precipitation, and the first molecular level chemical characterization of organic nitrogen in precipitation. The formation of oligomers in SOA helps to explain the presence of large multifunctional compounds and humic like substances (HULIS) that dominate particulate organic mass. Oligomers have low vapor pressures and remain in the particle phase after cloud evaporation, enhancing SOA. The chemical properties of the oligomers suggest that they are less hygroscopic than the monomeric reaction products (i.e., organic acids). Their elemental ratios are consistent with the hypothesis that oligomers are a large contributor to aged organic aerosol mass. The majority of the compounds identified in rainwater samples by advanced mass spectrometry appear to be products of atmospheric reactions, including known contributors to SOA formed from gas phase, aerosol phase, and in-cloud reactions in the atmosphere. The similarities between the complex organic matter in rainwater and SOA suggest that the large uncharacterized component of SOA is the main contributor to the large uncharacterized component of rainwater DOM.

Altieri, Katye Elisabeth

283

Low-level wastewater treatment facility process control operational test report  

International Nuclear Information System (INIS)

This test report documents the results obtained while conducting operational testing of a new TK 102 level controller and total outflow integrator added to the NHCON software that controls the Low-Level Wastewater Treatment Facility (LLWTF). The test was performed with WHC-SD-CP-OTP 154, PFP Low-Level Wastewater Treatment Facility Process Control Operational Test. A complete test copy is included in appendix A. The new TK 102 level controller provides a signal, hereafter referred to its cascade mode, to the treatment train flow controller which enables the water treatment process to run for long periods without continuous operator monitoring. The test successfully demonstrated the functionality of the new controller under standard and abnormal conditions expected from the LLWTF operation. In addition, a flow totalizer is now displayed on the LLWTF outlet MICON screen which tallies the process output in gallons. This feature substantially improves the ability to retrieve daily process volumes for maintaining accurate material balances

284

The Henry Ford production system: LEAN process redesign improves service in the molecular diagnostic laboratory: a paper from the 2008 William Beaumont hospital symposium on molecular pathology.  

Science.gov (United States)

Accurate and timely molecular test results play an important role in patient management; consequently, there is a customer expectation of short testing turnaround times. Baseline data analysis revealed that the greatest challenge to timely result generation occurred in the preanalytic phase of specimen collection and transport. Here, we describe our efforts to improve molecular testing turnaround times by focusing primarily on redesign of preanalytic processes using the principles of LEAN production. Our goal was to complete greater than 90% of the molecular tests in less than 3 days. The project required cooperation from different laboratory disciplines as well as individuals outside of the laboratory. The redesigned processes involved defining and standardizing the protocols and approaching blood and tissue specimens as analytes for molecular testing. The LEAN process resulted in fewer steps, approaching the ideal of a one-piece flow for specimens through collection/retrieval, transport, and different aspects of the testing process. The outcome of introducing the LEAN process has been a 44% reduction in molecular test turnaround time for tissue specimens, from an average of 2.7 to 1.5 days. In addition, extending LEAN work principles to the clinician suppliers has resulted in a markedly increased number of properly collected and shipped blood specimens (from 50 to 87%). These continuous quality improvements were accomplished by empowered workers in a blame-free environment and are now being sustained with minimal management involvement. PMID:19661386

Cankovic, Milena; Varney, Ruan C; Whiteley, Lisa; Brown, Ron; D'Angelo, Rita; Chitale, Dhananjay; Zarbo, Richard J

2009-09-01

285

Functional genomics in fish towards understanding stress and immune responses at a molecular level /  

OpenAIRE

Aquesta tesis doctoral està basada en estudiar la resposta immunològica dels peixos en models d'estrès i d'activació del sistema immune des la genòmica funcional. L'aplicació de tecnologies moleculars com el Differential Display van permetre identificar y clonar por primera vegada en orades (Sparus aurata) y en altres especies de peix, el gen enolasa. Aquest enzim glucolític s'ha plantejat per primera vegada com un bon marcador molecular per estudiar el benestar dels peixos. Per mitjà...

Ribas Cabezas, Laia

2006-01-01

286

Pseudomonas viridiflava, a Multi Host Plant Pathogen with Significant Genetic Variation at the Molecular Level  

OpenAIRE

The pectinolytic species Pseudomonas viridiflava has a wide host range among plants, causing foliar and stem necrotic lesions and basal stem and root rots. However, little is known about the molecular evolution of this species. In this study we investigated the intraspecies genetic variation of P. viridiflava amongst local (Cretan), as well as international isolates of the pathogen. The genetic and phenotypic variability were investigated by molecular fingerprinting (rep-PCR) and partial sequ...

Sarris, Panagiotis F.; Trantas, Emmanouil A.; Mpalantinaki, Evaggelia; Ververidis, Filippos; Goumas, Dimitrios E.

2012-01-01

287

Benchmarking energy use in the paper industry: a benchmarking study on process unit level  

Energy Technology Data Exchange (ETDEWEB)

There are large differences between paper mills in, e.g. feedstock use and grades produced, but typical processes are similar in all mills. The aim of this study is to benchmark the specific energy consumption (SEC) of similar processes within different paper mills in order to identify energy improvement potentials at process level. We have defined improvement potentials as measures that can be taken at mill/process level under assumed fixed inputs and outputs. We were able to use industrial data on detailed process level, and we conducted energy benchmarking comparisons in 23 Dutch paper mills. We calculated average SECs per process step for different paper grades, and we were able to identify ranges in SECs between mills producing the same grade. We found significant opportunities for energy efficiency improvement in the wire and press section as well as in the drying section. The total energy improvement potential based on identified best practices in these sections was estimated at 5.4 PJ (or 15 % of the total primary energy use in the selected mills). Energy use in the other processes was found to be too dependent on quality and product specifications to be able to quantify improvement potentials. Our results emphasise that even a benchmark on detailed process level does not lead to clear estimations of energy improvement potentials without accounting for structural effects and without having a decent understanding of the process.

Laurijssen, J. [Centre of Competence Paper and Board, IJsselburcht 3, 6825 BS Arnhem (Netherlands); Faaij, A.; Worrell, E. [Copernicus Institute, Utrecht University, Van Unnikgebouw, Heidelberglaan 2, 3584 CS Utrecht (Netherlands)

2013-02-15

288

Towards a seamless integration between process modeling descriptions at Business and Production levels - work in progress  

OpenAIRE

To fulfill increasing requirements in the manufacturing sector, companies are faced with several challenges. Three major challenges have been identified regarding time-to-market, vertical feedback loops and level of automation. Grafchart, a graphical language aimed for supervisory control applications, can be used from the process-planning phase, through the implementation phase and all the way to the phase for execution of the process control logics, on the lower levels of the Automation tri...

Gerber, Tobias; Theorin, Alfred; Johnsson, Charlotta

2012-01-01

289

Design and Development of Molecular Imaging Probes  

OpenAIRE

Molecular imaging, the visualization, characterization and measurement of biological processes at the cellular, subcellular level, or even molecular level in living subjects, has rapidly gained importance in the dawning era of personalized medicine. Molecular imaging takes advantage of the traditional diagnostic imaging techniques and introduces molecular imaging probes to determine the expression of indicative molecular markers at different stages of diseases and disorders. As a key componen...

Chen, Kai; Chen, Xiaoyuan

2010-01-01

290

Information theory and signal transduction systems: from molecular information processing to network inference.  

Science.gov (United States)

Sensing and responding to the environment are two essential functions that all biological organisms need to master for survival and successful reproduction. Developmental processes are marshalled by a diverse set of signalling and control systems, ranging from systems with simple chemical inputs and outputs to complex molecular and cellular networks with non-linear dynamics. Information theory provides a powerful and convenient framework in which such systems can be studied; but it also provides the means to reconstruct the structure and dynamics of molecular interaction networks underlying physiological and developmental processes. Here we supply a brief description of its basic concepts and introduce some useful tools for systems and developmental biologists. Along with a brief but thorough theoretical primer, we demonstrate the wide applicability and biological application-specific nuances by way of different illustrative vignettes. In particular, we focus on the characterisation of biological information processing efficiency, examining cell-fate decision making processes, gene regulatory network reconstruction, and efficient signal transduction experimental design. PMID:24953199

Mc Mahon, Siobhan S; Sim, Aaron; Filippi, Sarah; Johnson, Robert; Liepe, Juliane; Smith, Dominic; Stumpf, Michael P H

2014-11-01

291

Reading Leveled Books in Assessment-Saturated Classrooms: A Close Examination of Unmarked Processes of Assessment  

Science.gov (United States)

This article examines the reading of leveled books and the assessment of students' reading levels in a public school classroom. The purpose of the research study was to examine how these processes of assessment, which often go unnoticed, shaped the ways reading and readers were defined. The research was located in a third grade, public school…

Kontovourki, Stavroula

2012-01-01

292

Dynamics of two-photon process in three-level system  

International Nuclear Information System (INIS)

Dynamical behaviour of a two-photon process in a three-level system with a common upper level is examined. The autoecho phenomenon is described. This equantum nonlinear phenomenon consists of the revival and collapse of the fast oscillations for dynamical parameters due to the coherence of an initial pumping

293

Spectroscopic Studies of Atomic and Molecular Processes in the Edge Region of Magnetically Confined Fusion Plasmas  

International Nuclear Information System (INIS)

Edge plasma studies are of vital importance for understanding plasma-wall interactions in magnetically confined fusion devices. These interactions determine the transport of neutrals into the plasma, and the properties of the plasma discharge. This presentation deals with optical spectroscopic studies of the plasma boundary, and their role in elucidating the prevailing physical conditions. Recorded spectra are of four types: emission spectra of ions and atoms, produced by electron impact excitation and by charge-exchange recombination, atomic spectra arising from electron impact-induced molecular dissociation and ionisation, visible spectra of molecular hydrogen and its isotopic combinations, and laser-induced fluorescence (LIF) spectra. The atomic spectra are strongly influenced by the confining magnetic field (Zeeman and Paschen-Back effects), which produces characteristic features useful for species identification, temperature determination by Doppler broadening, and studies of chemical and physical sputtering. Detailed analysis of the Zeeman components in both optical and LIF spectra shows that atomic hydrogen is produced in various velocity classes, some related to the relevant molecular Franck-Condon energies. The latter reflect the dominant electron collision processes responsible for production of atoms from molecules. This assignment has been verified by gas-puffing experiments through special test limiters. The higher-energy flanks of hydrogen line profiles r-energy flanks of hydrogen line profiles probably also show the influence of charge-exchange reactions with molecular ions accelerated in the plasma sheath ('scrape-off layer') separating limiter surfaces from the edge plasma, in analogy to acceleration in the cathode-fall region of gas discharges. While electron collisions play a vital role in generating the spectra, ion collisions with excited atomic radiators act through re-distribution of population among the atomic fine-structure sublevels, and momentum transfer to the atomic nuclei via ion-induced dipole collisions with the bound electrons. The ions are thus important in randomising and equilibrating the velocity distribution of atomic products of molecular dissociation

294

Broadening the horizon – level 2.5 of the HUPO-PSI format for molecular interactions  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Molecular interaction Information is a key resource in modern biomedical research. Publicly available data have previously been provided in a broad array of diverse formats, making access to this very difficult. The publication and wide implementation of the Human Proteome Organisation Proteomics Standards Initiative Molecular Interactions (HUPO PSI-MI format in 2004 was a major step towards the establishment of a single, unified format by which molecular interactions should be presented, but focused purely on protein-protein interactions. Results The HUPO-PSI has further developed the PSI-MI XML schema to enable the description of interactions between a wider range of molecular types, for example nucleic acids, chemical entities, and molecular complexes. Extensive details about each supported molecular interaction can now be captured, including the biological role of each molecule within that interaction, detailed description of interacting domains, and the kinetic parameters of the interaction. The format is supported by data management and analysis tools and has been adopted by major interaction data providers. Additionally, a simpler, tab-delimited format MITAB2.5 has been developed for the benefit of users who require only minimal information in an easy to access configuration. Conclusion The PSI-MI XML2.5 and MITAB2.5 formats have been jointly developed by interaction data producers and providers from both the academic and commercial sector, and are already widely implemented and well supported by an active development community. PSI-MI XML2.5 enables the description of highly detailed molecular interaction data and facilitates data exchange between databases and users without loss of information. MITAB2.5 is a simpler format appropriate for fast Perl parsing or loading into Microsoft Excel.

Cusick Michael E

2007-10-01

295

Proficiency Level and the Interaction of Lexical and Morphosyntactic Information during L2 Sentence Processing  

Science.gov (United States)

Using a self-paced reading task, the present study explores how second language (L2) German speakers at different proficiency levels use case-marking information when processing subject-object ambiguities in German. Results indicate that advanced L2 German speakers rapidly integrated case-marking information during online processing, exhibiting a…

Jackson, Carrie

2008-01-01

296

West Valley demonstration project: alternative processes for solidifying the high-level wastes  

Energy Technology Data Exchange (ETDEWEB)

In 1980, the US Department of Energy (DOE) established the West Valley Solidification Project as the result of legislation passed by the US Congress. The purpose of this project was to carry out a high level nuclear waste management demonstration project at the Western New York Nuclear Service Center in West Valley, New York. The DOE authorized the Pacific Northwest Laboratory (PNL), which is operated by Battelle Memorial Institute, to assess alternative processes for treatment and solidification of the WNYNSC high-level wastes. The Process Alternatives Study is the suject of this report. Two pretreatment approaches and several waste form processes were selected for evaluation in this study. The two waste treatment approaches were the salt/sludge separation process and the combined waste process. Both terminal and interim waste form processes were studied.

Holton, L.K.; Larson, D.E.; Partain, W.L.; Treat, R.L.

1981-10-01

297

Process description and plant design for preparing ceramic high-level waste forms  

International Nuclear Information System (INIS)

The ceramics process flow diagram has been simplified and upgraded to utilize only two major processing steps - fluid-bed calcination and hot isostatic press consolidating. Full-scale fluid-bed calcination has been used at INEL to calcine high-level waste for 18 y; and a second-generation calciner, a fully remotely operated and maintained calciner that meets ALARA guidelines, started calcining high-level waste in 1982. Full-scale hot isostatic consolidation has been used by DOE and commercial enterprises to consolidate radioactive components and to encapsulate spent fuel elements for several years. With further development aimed at process integration and parametric optimization, the operating knowledge of full-scale demonstration of the key process steps should be rapidly adaptable to scale-up of the ceramic process to full plant size. Process flowsheets used to prepare ceramic and glass waste forms from defense and commercial high-level liquid waste are described. Preliminary layouts of process flow diagrams in a high-level processing canyon were prepared and used to estimate the preliminary cost of the plant to fabricate both waste forms. The estimated costs for using both options were compared for total waste management costs of SRP high-level liquid waste. Using our design, for both the ceramic and glass plant, capital and operating costs are essentially the same for both defense and commercial wastes, but total waste management costs are calculated to be significantly less for defense wastes using the ceramic option. It is concluded from this and other studies that the ceramic form may offer important advantages over glass in leach resistance, waste loading, density, and process flexibility. Preliminary economic calculations indicate that ceramics must be considered a leading candidate for the form to immobilize high-level wastes

298

Extreme values and the level-crossing problem: an application to the Feller process.  

Science.gov (United States)

We review the question of the extreme values attained by a random process. We relate it to level crossings to one boundary (first-passage problems) as well as to two boundaries (escape problems). The extremes studied are the maximum, the minimum, the maximum absolute value, and the range or span. We specialize in diffusion processes and present detailed results for the Wiener and Feller processes. PMID:24827192

Masoliver, Jaume

2014-04-01

299

Extreme values and the level-crossing problem: An application to the Feller process  

Science.gov (United States)

We review the question of the extreme values attained by a random process. We relate it to level crossings to one boundary (first-passage problems) as well as to two boundaries (escape problems). The extremes studied are the maximum, the minimum, the maximum absolute value, and the range or span. We specialize in diffusion processes and present detailed results for the Wiener and Feller processes.

Masoliver, Jaume

2014-04-01

300

Actualities on molecular pathogenesis and repairing processes of cerebral damage in perinatal hypoxic-ischemic encephalopathy  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Hypoxic-ischemic encephalopathy (HIE is the most important cause of cerebral damage and long-term neurological sequelae in the perinatal period both in term and preterm infant. Hypoxic-ischemic (H-I injuries develop in two phases: the ischemic phase, dominated by necrotic processes, and the reperfusion phase, dominated by apoptotic processes extending beyond ischemic areas. Due to selective ischemic vulnerability, cerebral damage affects gray matter in term newborns and white matter in preterm newborns with the typical neuropathological aspects of laminar cortical necrosis in the former and periventricular leukomalacia in the latter. This article summarises the principal physiopathological and biochemical processes leading to necrosis and/or apoptosis of neuronal and glial cells and reports recent insights into some endogenous and exogenous cellular and molecular mechanisms aimed at repairing H-I cerebral damage.

Praticò Andrea D

2010-09-01

301

Proposal of flexible atomic and molecular process management for Monte Carlo impurity transport code based on object oriented method  

International Nuclear Information System (INIS)

Monte Carlo simulation code on impurity transport has been developed by several groups to be utilized mainly for fusion related edge plasmas. State of impurity particle is determined by atomic and molecular processes such as ionization, charge exchange in plasma. A lot of atomic and molecular processes have been considered because the edge plasma has not only impurity atoms, but also impurity molecules mainly related to chemical erosion of carbon materials, and their cross sections have been given experimentally and theoretically. We need to reveal which process is essential in a given edge plasma condition. Monte Carlo simulation code, which takes such various atomic and molecular processes into account, is necessary to investigate the behavior of impurity particle in plasmas. Usually, the impurity transport simulation code has been intended for some specific atomic and molecular processes so that the introduction of a new process forces complicated programming work. In order to evaluate various proposed atomic and molecular processes, a flexible management of atomic and molecular reaction should be established. We have developed the impurity transport simulation code based on object-oriented method. By employing object-oriented programming, we can handle each particle as 'object', which enfolds data and procedure function itself. A user (notice, not programmer) can define property of each particle species and the related atomic and molecular processes and then each mic and molecular processes and then each 'object' is defined by analyzing this information. According to the relation among plasma particle species, objects are connected with each other and change their state by themselves. Dynamic allocation of these objects to program memory is employed to adapt for arbitrary number of species and atomic/molecular reactions. Thus we can treat arbitrary species and process starting from, for instance, methane and acetylene. Such a software procedure would be useful also for industrial application plasmas, which enfolds more complicated atomic and molecular process such as SiH4. In this paper, a detailed description and idea to take care of arbitrary particle species and atomic/molecular process are presented based on object-oriented method. We will also demonstrate that this simulation is successful in a concrete example. (orig.)

302

Pushing CT and MR Imaging to the Molecular Level for Studying the “Omics”: Current Challenges and Advancements  

OpenAIRE

During the past decade, medical imaging has made the transition from anatomical imaging to functional and even molecular imaging. Such transition provides a great opportunity to begin the integration of imaging data and various levels of biological data. In particular, the integration of imaging data and multiomics data such as genomics, metabolomics, proteomics, and pharmacogenomics may open new avenues for predictive, preventive, and personalized medicine. However, to promote imaging-omics ...

Hsuan-Ming Huang; Yi-Yu Shih

2014-01-01

303

Tank waste remediation system phase I high-level waste feed processability assessment report  

Energy Technology Data Exchange (ETDEWEB)

This report evaluates the effects of feed composition on the Phase I high-level waste immobilization process and interim storage facility requirements for the high-level waste glass.Several different Phase I staging (retrieval, blending, and pretreatment) scenarios were used to generate example feed compositions for glass formulations, testing, and glass sensitivity analysis. Glass models and data form laboratory glass studies were used to estimate achievable waste loading and corresponding glass volumes for various Phase I feeds. Key issues related to feed process ability, feed composition, uncertainty, and immobilization process technology are identified for future consideration in other tank waste disposal program activities.

Lambert, S.L.; Stegen, G.E., Westinghouse Hanford

1996-08-01

304

Virtual Atomic and Molecular Data Centre: Level 3 Service and Future Prospects  

Science.gov (United States)

The Virtual Atomic and Molecular Data Centre (VAMDC, http://www.vamdc.eu) is an international Consortium that has created an interoperable e-science infrastructure for the exchange of atomic and molecular data. The VAMDC defines standards for the exchange of atomic and molecular data, develop reference implementation of those standards, deploys registries of internet resources (yellow pages), designs user applications in order to meet the user needs, builds data access layers above databases to provide unified outputs from these databases, cares about asynchronous queries with workflows and connects its infrastructure to the grid. The paper describes the current service deployment of the VAMDC data infrastructure across our registered databases and the key features of the current infrastructure.

Dubernet, M. L.; Rixon, G.; Doronin, M.; VAMDC Collaboration

2015-03-01

305

Nonadiabatic approach for resonant molecular multiphoton absorption processes in intense infrared laser fields  

International Nuclear Information System (INIS)

A nonperturbative approach for efficient and accurate treatment of the molecular multiphoton absorption (MPA) quantum dynamics in intense infrared (IR) laser fields is presented. The approach is based on the adiabatic separation of the fast vibrational motion from the slow rotational motion, incorporating the fact that the IR laser frequency is close to the frequencies of adjacent vibrational transitions. One thus first solves the quasivibrational energy (QVE) states (or, equivalently, the dressed vibrational states) with molecular orientation fixed. This reduces the computationally often formidable (vibrational-rotational) Floquet matrix analysis to a manageable scale, and, in addition, provides useful physical insights for understanding the nonlinear MPA dynamics. The QVE levels are found to be grouped into distinct energy bands, characterized by the IR frequency, with each band providing an effective potential for molecular rotation. Whereas the interband couplings are totally negligible, the intraband nonadiabatic angular couplings are the main driving mechanisms for inducing resonant vibrational--rotational multiphoton transitions. The utility of the method is illustrated by a detailed study of the sequential MPA spectra for 12C 16O molecule, including state-to-state multiquantum transitions and transitions from initially thermally distributed states as a whole. Results are presented for the case of IR laser intensity 50 GW/cm2 anIR laser intensity 50 GW/cm2 and frequencies ranging from 2115 to 2165 cm-1. Excellent agreement of the MPA spectra obtained by the nonadiabatic approach and the exact Floquet matrix method was observed in all fine details

306

Level scheme of /sup 148/Pm and the s-process neutron density  

International Nuclear Information System (INIS)

A level scheme of /sup 148/Pm up to 800 keV is deduced from gamma-ray coincidence data and published particle transfer data. Approximately 106 gamma-ray transitions have been placed between 36 levels. We have identified three levels below 500 keV in excitation which decay to both the ground state and to the isomeric level at 137 keV. The presence of these levels guarantees that /sup 148/Pm/sup g//sup ,//sup m/ are in thermal equilibrium during the s process. The s-process neutron density inferred from the branch point at /sup 148/Pm is deduced to be 3 x 108/cm3

307

Cellular and molecular mechanism study of declined intestinal transit function in the cholesterol gallstone formation process of the guinea pig.  

Science.gov (United States)

The aim of this study was to investigate the cellular and molecular mechanisms of declined intestinal transit (IT) function in the cholesterol gallstone (CG) formation process. Forty guinea pigs were divided into an experimental group (EG) and a control group (CoG), and the reverse transcription-polymerase chain reaction (RT-PCR) was performed for the analysis of c-kit and stem cell factor (scf) mRNA expression in the small bowel. In addition, immunofluorescence staining and confocal laser microscopy were performed for the observation of the changes in the number of interstitial cells of Cajal (ICCs) in the terminal ileum of each group. RT-PCR showed that, compared with the CoG, the intestinal c-kit and scf mRNA expression levels in the EG were significantly decreased; the average positive area of ICCs in the ileum in the EG was also significantly reduced. During the diet-induced CG formation procedure, the c-kit and scf mRNA expression levels in the small intestine decreased and the number of ICCs decreased. Inhibition of the c-kit/scf pathway may be involved in the declined IT function during the CG formation process. PMID:25289052

Fan, Ying; Wu, Shuodong; Yin, Zhenhua; Fu, Bei-Bei

2014-11-01

308

Observation of the amorphous zinc oxide recrystalline process by molecular dynamics simulation  

OpenAIRE

The detailed structural variations of amorphous zinc oxide (ZnO) as well as wurtzite (B4) and zinc blende (B3) crystal structures during the temperature elevation process were observed by molecular dynamics simulation. The amorphous ZnO structure was first predicted through the simulated-annealing basin-hopping algorithm with the criterion to search for the least stable structure. The density and X-ray diffraction profiles of amorphous ZnO of the structure were in agreement with previous repo...

Lin, Ken-huang; Sun, Shih-jye; Ju, Shin-pon; Tsai, Jen-yu; Chen, Hsin-tsung; Hsieh, Jin-yuan

2013-01-01

309

Molecular and physiological basic processes in the context of radiation protection  

International Nuclear Information System (INIS)

The aim of this paper is an attempt to answer the question why accumulated knowledge on molecular basis of biological effects of ionizing radiation have not yet resulted in in sufficiently successful chemical radiation protection. In the past decade experimental results which demonstrated a direct regulatory role of some radicals in the main physiological processes such as vascular tone successfully emphasize the significance of old experimental results (the best protection can be achieved through physiological manipulations) connecting them to new data on free radical evolvement and the application of various free radical scavengers in radiation protection, which represents the most appropriate approach to the problem. (author)

310

Mathematical models of non-linear phenomena, processes and systems: from molecular scale to planetary atmosphere  

CERN Document Server

This book consists of twenty seven chapters, which can be divided into three large categories: articles with the focus on the mathematical treatment of non-linear problems, including the methodologies, algorithms and properties of analytical and numerical solutions to particular non-linear problems; theoretical and computational studies dedicated to the physics and chemistry of non-linear micro-and nano-scale systems, including molecular clusters, nano-particles and nano-composites; and, papers focused on non-linear processes in medico-biological systems, including mathematical models of ferments, amino acids, blood fluids and polynucleic chains.

2013-01-01

311

Molecular-dynamics simulations of nucleation and crystallization processes of laser crystallized poly-Si  

International Nuclear Information System (INIS)

The nucleation and crystallization processes of excimer-laser annealed Si on a SiO2 substrate for complete melting conditions have been investigated by using molecular-dynamics simulations. In the early stage of nucleation, the preferential growth of nuclei with a {111} face normal to the surface was originated from the {111} twin boundaries with a low surface energy. The partial rotation of the dimer leads to the growth of {111}-oriented nuclei along twins that have different stacking sequences. The recombination of vacancies and dimers at the solidification front is directly related to {111} growth from the twin boundaries

312

Effects of Pre-Existing Defects on Nanoimprint Process Investigated by Molecular Dynamics Simulation  

Science.gov (United States)

In current study molecular dynamics (MD) simulations are performed to reveal effects of pre-existing defects on nanoimprint of single crystal aluminum (Al) thin films. Simulation results suggest that critical force required for plastic deformation initiation decreases with the increase of vacancy volume fraction, but increases with the interstitial volume fraction. It is found that adsorption phenomenon is affected by pre-existing defects, as adsorption phenomenon weakens with the increasing interstitial volume fraction. Pre-existing defects have significant influence on the deformation mechanisms and imprint forces during the nanoimprint processes. Simulation results also show that surface deformation is strongly affected by pre-existing defects.

Yuan, Ying; Zhang, Junjie; Sun, Tao; Liu, Cong

2014-01-01

313

Simulating Picosecond X-ray Diffraction from shocked crystals by Post-processing Molecular Dynamics Calculations  

Energy Technology Data Exchange (ETDEWEB)

Calculations of the x-ray diffraction patterns from shocked crystals derived from the results of Non-Equilibrium-Molecular-Dynamics (NEMD) simulations are presented. The atomic coordinates predicted by the NEMD simulations combined with atomic form factors are used to generate a discrete distribution of electron density. A Fast-Fourier-Transform (FFT) of this distribution provides an image of the crystal in reciprocal space, which can be further processed to produce quantitative simulated data for direct comparison with experiments that employ picosecond x-ray diffraction from laser-irradiated crystalline targets.

Kimminau, G; Nagler, B; Higginbotham, A; Murphy, W; Park, N; Hawreliak, J; Kadau, K; Germann, T C; Bringa, E M; Kalantar, D; Lorenzana, H; Remington, B; Wark, J

2008-06-19

314

Adaptation and learning of molecular networks as a description of cancer development at the systems-level: Potential use in anti-cancer therapies  

CERN Document Server

There is a widening recognition that cancer cells are products of complex developmental processes. Carcinogenesis and metastasis formation are increasingly described as systems-level, network phenomena. Here we propose that malignant transformation is a two-phase process, where an initial increase of system plasticity is followed by a decrease of plasticity at late stages of carcinogenesis as a model of cellular learning. We describe the hallmarks of increased system plasticity of early, tumor initiating cells, such as increased noise, entropy, conformational and phenotypic plasticity, physical deformability, cell heterogeneity and network rearrangements. Finally, we argue that the large structural changes of molecular networks during cancer development necessitate a rather different targeting strategy in early and late phase of carcinogenesis. Plastic networks of early phase cancer development need a central hit, while rigid networks of late stage primary tumors or established metastases should be attacked b...

Gyurko, David M; Modos, Dezso; Lenti, Katalin; Korcsmaros, Tamas; Csermely, Peter

2013-01-01

315

New tools for the investigations of Neuro-AIDS at a molecular level: The potential role of data-mining  

OpenAIRE

Cognitive impairment represents the most significant and devastating neurological complication associated with HIV infection. Despite recent advances in our knowledge of the clinical features, pathogenesis, and molecular aspects of HIV-related dementia, current diagnostic strategies are associated with significant limitations. It has been suggested that the use of some biomarkers may assist researchers and clinicians in predicting the onset of the disease process and in evaluating th...

Orlando, Bruno; Giacomelli, Luca; Chiappelli, Francesco; Barkhordarian, Andre?

2013-01-01

316

MZmine 2: Modular framework for processing, visualizing, and analyzing mass spectrometry-based molecular profile data  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Mass spectrometry (MS coupled with online separation methods is commonly applied for differential and quantitative profiling of biological samples in metabolomic as well as proteomic research. Such approaches are used for systems biology, functional genomics, and biomarker discovery, among others. An ongoing challenge of these molecular profiling approaches, however, is the development of better data processing methods. Here we introduce a new generation of a popular open-source data processing toolbox, MZmine 2. Results A key concept of the MZmine 2 software design is the strict separation of core functionality and data processing modules, with emphasis on easy usability and support for high-resolution spectra processing. Data processing modules take advantage of embedded visualization tools, allowing for immediate previews of parameter settings. Newly introduced functionality includes the identification of peaks using online databases, MSn data support, improved isotope pattern support, scatter plot visualization, and a new method for peak list alignment based on the random sample consensus (RANSAC algorithm. The performance of the RANSAC alignment was evaluated using synthetic datasets as well as actual experimental data, and the results were compared to those obtained using other alignment algorithms. Conclusions MZmine 2 is freely available under a GNU GPL license and can be obtained from the project website at: http://mzmine.sourceforge.net/. The current version of MZmine 2 is suitable for processing large batches of data and has been applied to both targeted and non-targeted metabolomic analyses.

Villar-Briones Alejandro

2010-07-01

317

MOLECULAR SIEVES AS CATALYSTS FOR METHANOL DEHYDRATION IN THE LPDMEtm PROCESS  

Energy Technology Data Exchange (ETDEWEB)

Several classes of molecular sieves were investigated as methanol dehydration catalysts for the LPDME{trademark} (liquid-phase dimethyl ether) process. Molecular sieves offer a number of attractive features as potential catalysts for the conversion of methanol to DME. These include (1) a wide range of acid strengths, (2) diverse architectures and channel connectivities that provide latitude for steric control, (3) high active site density, (4) well-investigated syntheses and characterization, and (5) commercial availability in some cases. We directed our work in two areas: (1) a general exploration of the catalytic behavior of various classes of molecular sieves in the LPDME{trademark} system and (2) a focused effort to prepare and test zeolites with predominantly Lewis acidity. In our general exploration, we looked at such diverse materials as chabazites, mordenites, pentasils, SAPOs, and ALPOs. Our work with Lewis acidity sought to exploit the structural advantages of zeolites without the interfering effects of deleterious Broensted sites. We used zeolite Ultrastable Y (USY) as our base material because it possesses a high proportion of Lewis acid sites. This work was extended by modifying the USY through ion exchange to try to neutralize residual Broensted acidity.

Andrew W. Wang

2002-04-01

318

MOLECULAR SIEVES AS CATALYSTS FOR METHANOL DEHYDRATION IN THE LPDMEtm PROCESS; TOPICAL  

International Nuclear Information System (INIS)

Several classes of molecular sieves were investigated as methanol dehydration catalysts for the LPDME(trademark) (liquid-phase dimethyl ether) process. Molecular sieves offer a number of attractive features as potential catalysts for the conversion of methanol to DME. These include (1) a wide range of acid strengths, (2) diverse architectures and channel connectivities that provide latitude for steric control, (3) high active site density, (4) well-investigated syntheses and characterization, and (5) commercial availability in some cases. We directed our work in two areas: (1) a general exploration of the catalytic behavior of various classes of molecular sieves in the LPDME(trademark) system and (2) a focused effort to prepare and test zeolites with predominantly Lewis acidity. In our general exploration, we looked at such diverse materials as chabazites, mordenites, pentasils, SAPOs, and ALPOs. Our work with Lewis acidity sought to exploit the structural advantages of zeolites without the interfering effects of deleterious Broensted sites. We used zeolite Ultrastable Y (USY) as our base material because it possesses a high proportion of Lewis acid sites. This work was extended by modifying the USY through ion exchange to try to neutralize residual Broensted acidity

319

Shocks in dense clouds. IV. Effects of grain-grain processing on molecular line emission  

Science.gov (United States)

Context. Grain-grain processing has been shown to be an indispensable ingredient of shock modelling in high density environments. For densities higher than ~105 cm-3, shattering becomes a self-enhanced process that imposes severe chemical and dynamical consequences on the shock characteristics. Shattering is accompanied by the vaporization of grains, which can, in addition to sputtering, directly release SiO to the gas phase. Given that SiO rotational line radiation is used as a major tracer of shocks in dense clouds, it is crucial to understand the influence of vaporization on SiO line emission. Aims: We extend our study of the impact of grain-grain processing on C-type shocks in dense clouds. Various values of the magnetic field are explored. We study the corresponding consequences for molecular line emission and, in particular, investigate the influence of shattering and related vaporization on the rotational line emission of SiO. Methods: We have developed a recipe for implementing the effects of shattering and vaporization into a 2-fluid shock model, resulting in a reduction of computation time by a factor ~100 compared to a multi-fluid modelling approach. This implementation was combined with an LVG-based modelling of molecular line radiation transport. Using this combined model we calculated grids of shock models to explore the consequences of different dust-processing scenarios. Results: Grain-grain processing is shown to have a strong influence on C-type shocks for a broad range of magnetic fields: the shocks become hotter and thinner. The reduction in column density of shocked gas lowers the intensity of molecular lines, at the same time as higher peak temperatures increase the intensity of highly excited transitions compared to shocks without grain-grain processing. For OH the net effect is an increase in line intensities, while for CO and H2O it is the contrary. The intensity of H2 emission is decreased in low transitions and increased for highly excited lines. For all molecules, the highly excited lines become sensitive to the value of the magnetic field. Although vaporization increases the intensity of SiO rotational lines, this effect is weakened by the reduced shock width. The release of SiO early in the hot shock changes the excitation characteristics of SiO radiation, although it does not yield an increase in width for the line profiles. To significantly increase the intensity and width of SiO rotational lines, SiO needs to be present in grain mantles. Appendices are available in electronic form at http://www.aanda.org

Anderl, S.; Guillet, V.; Pineau des Forêts, G.; Flower, D. R.

2013-08-01

320

Assessing the impact of synchrotron X-ray irradiation on proteinaceous specimens at macro and molecular levels.  

Science.gov (United States)

Synchrotron radiation (SR) has become a preferred technique for the analysis of a wide range of archeological samples, artwork, and museum specimens. While SR is called a nondestructive technique, its effect on proteinaceous specimens has not been fully investigated at the molecular level. To investigate the molecular level effects of synchrotron X-ray on proteinaceous specimens, we propose a methodology where four variables are considered: (1) type of specimen: samples ranging from amino acids to proteinaceous objects such as silk, wool, parchment, and rabbit skin glue were irradiated; (2) synchrotron X-ray energy; (3) beam intensity; (4) irradiation time. Irradiated specimens were examined for both macroscopic and molecular effects. At macroscopic levels, color change, brittleness, and solubility enhancement were observed for several samples within 100 s of irradiation. At molecular levels, the method allowed one to quantify significant amino acid modifications. Aspartic acid (Asp), wool, parchment, and rabbit skin glue showed a significant increase in Asp racemization upon increasing irradiation time with rabbit skin glue showing the greatest increase in d-Asp formation. In contrast, Asp in silk, pure cystine (dimer of cysteine), and asparagine (Asn) did not show signs of racemization at the irradiation times studied; however, the latter two compounds showed significant signs of decomposition. Parchment and rabbit skin glue exhibited racemization of Asp, as well as racemization of isoleucine (Ile) and phenylalanine (Phe) after 100 s of irradiation with a focused beam. Under the experimental conditions and sample type and dimensions used here, more change was observed for focused and low energy (8 keV) beams than unfocused or higher energy (22 keV) beams. These results allow quantification of the change induced at the molecular level on proteinaceous specimens by synchrotron X-ray radiation and help to define accurate thresholds to minimize the probability of damage occurring to cultural heritage specimens. For most samples, damage was usually observed in the 1-10 s time scale, which is about an order of magnitude longer than SR studies of cultural heritage under X-ray fluorescence (XRF) mode; however, it is consistent with the duration of X-ray absorption spectroscopy (XAS) and microcomputed tomography (?CT) measurements. PMID:25186608

Moini, Mehdi; Rollman, Christopher M; Bertrand, Loïc

2014-10-01

321

Prospect on the atomic and molecular processes in plasmas. Collisional radiative model for complex ions  

International Nuclear Information System (INIS)

The collisional radiative model of multiple-charged ions of high-Z elements is described. Characteristic features of the level structure and atomic processes, and approximate methods to calculate ion abundance and level populations are presented. In the development of an atomic model, a large number of energy levels and collisional radiative rates are calculated using the atomic data codes. The usefulness of the super configuration model in constructing a simpler atomic model is explained using the results of a collisional radiative model for soft x-ray lasers. (author)

322

Thermal- and urea-induced unfolding processes of glutathione S-transferase by molecular dynamics simulation.  

Science.gov (United States)

The Schistosoma juponicum 26 kDa glutathione S-transferase (sj26GST) consists of the N-terminal domain (N-domain), containing three alpha-helices (named H1-H3) and four anti-parallel beta-strands (S1-S4), and the C-terminal domain (C-domain), comprising five alpha-helices (named H4-H8). In present work, molecular dynamics simulations and fluorescence spectroscopic were used to gain insights into the unfolding process of sj26GST. The molecular dynamics simulations on sj26GST subunit both in water and in 8 M urea were carried out at 300 K, 400 K and 500 K, respectively. Spectroscopic measurements were employed to monitor structural changes. Molecular dynamics simulations of sj26GST subunit induced by urea and temperature showed that the initial unfolding step of sj26GST both in water and urea occurred on N-domain, involving the disruption of helices H2, H3 and strands S3 and S4, whereas H6 was the last region exposed to solution and was the last helix to unfold. Moreover, simulations analyses combining with fluorescence and circular dichroism spectra indicated that N-domain could not fold independent, suggesting that correct folding of N-domain depended on its interactions with C-domain. We further proposed that the folding of GSTs could begin with the hydrophobic collapse of C-domain whose H4, H5, H6 and H7 could move close to each other and form a hydrophobic core, especially H6 wrapped in the hydrophobic center and beginning spontaneous formation of the helix. S3, S4, H3, and H2 could form in the wake of the interaction between C-domain and N-domain. The paper can offer insights into the molecular mechanism of GSTs unfolding. © 2014 Wiley Periodicals, Inc. Biopolymers 103: 247-259, 2015. PMID:25403814

Li, Jiahuang; Chen, Yuan; Yang, Jie; Hua, Zichun

2015-05-01

323

Board-invited review: Sensitivity and responses of functional groups to feed processing methods on a molecular basis  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract In complex feed structures, there exist main chemical functional groups which are associated with nutrient utilization and availability and functionality. Each functional group has unique molecular structure therefore produce unique molecular vibration spectral profile. Feed processing has been used to improve nutrient utilization for many years. However, to date, there was little study on processing-induced changes of feed intrinsic structure and functional groups on a molecular basis within intact tissue. This is because limited research technique is available to study inherent structure on a molecular basis. Recently bioanalytical techniques: such as Synchrotron Infrared Microspectroscopy as well as Diffuse Reflectance Infrared Fourier Transform molecular spectroscopy have been developed. These techniques enable to detect molecular structure change within intact tissues. These techniques can prevent destruction or alteration of the intrinsic protein structures during processing for analysis. However, these techniques have not been used in animal feed and nutrition research. The objective of this review was show that with the advanced technique, sensitivity and responses of functional groups to feed processing on a molecular basis could be detected in my research team. These functional groups are highly associated with nutrient utilization in animals.

Yu Peiqiang

2012-12-01

324

Mercury reduction and removal during high-level radioactive waste processing and vitrification  

International Nuclear Information System (INIS)

A reference process for immobilizing the high-level radioactive waste in borosilicate glass has been developed at the Savannah River Plant. This waste contains a substantial amount of mercury from separations processing. Because mercury will not remain in borosilicate glass at the processing temperature, mercury must be removed before vitrification or must be handled in the off-gas system. A process has been developed to remove mercury by reduction with formic acid prior to vitrification. Additional benefits of formic acid treatment include improved sludge handling and glass melter redox control

325

Critical assessment of methods for treating airborne effluents from high-level waste solidification processes  

International Nuclear Information System (INIS)

Off-gas treatment systems are reviewed for high-temperature processes which are being developed for the solidification of high-level liquid wastes from nuclear fuel reprocessing plants. A brief description of each of the processes is given and detailed analyses are made of the expected magnitudes of airborne effluent release rates from each system. The estimated release rates of the various processes are compared with present and anticipated regulatory limits. A number of recommendations are made for additional development studies to better understand and control certain airborne effluents from the solidification processes

326

Critical assessment of methods for treating airborne effluents from high-level waste solidification processes  

Energy Technology Data Exchange (ETDEWEB)

Off-gas treatment systems are reviewed for high-temperature processes which are being developed for the solidification of high-level liquid wastes from nuclear fuel reprocessing plants. A brief description of each of the processes is given and detailed analyses are made of the expected magnitudes of airborne effluent release rates from each system. The estimated release rates of the various processes are compared with present and anticipated regulatory limits. A number of recommendations are made for additional development studies to better understand and control certain airborne effluents from the solidification processes.

Christian, J.D.; Pence, D.T.

1977-06-01

327

Site selection and characterization processes for deep geologic disposal of high level nuclear waste  

International Nuclear Information System (INIS)

In this paper, the major elements of the site selection and characterization processes used in the U. S. high level waste program are discussed. While much of the evolution of the site selection and characterization processes have been driven by the unique nature of the U. S. program, these processes, which are well-defined and documented, could be used as an initial basis for developing site screening, selection, and characterization programs in other countries. Thus, this paper focuses more on the process elements than the specific details of the U. S. program. (author). 3 refs., 2 tabs., 5 figs

328

Site selection and characterization processes for deep geologic disposal of high level nuclear waste  

International Nuclear Information System (INIS)

In this paper, the major elements of the site selection and characterization processes used in the US high level waste program are discussed. While much of the evolution of the site selection and characterization processes have been driven by the unique nature of the US program, these processes, which are well defined and documented, could be used as an initial basis for developing site screening, selection, and characterization programs in other countries. Thus, this paper focuses more on the process elements than the specific details of the US program

329

RECENT PROCESS AND EQUIPMENT IMPROVEMENTS TO INCREASE HIGH LEVEL WASTE THROUGHPUT AT THE DEFENSE WASTE PROCESSING FACILITY  

Energy Technology Data Exchange (ETDEWEB)

The Savannah River Site's (SRS) Defense Waste Processing Facility (DWPF) began stabilizing high level waste (HLW) in a glass matrix in 1996. Over the past few years, there have been several process and equipment improvements at the DWPF to increase the rate at which the high level waste can be stabilized. These improvements have either directly increased waste processing rates or have desensitized the process to upsets, thereby minimizing downtime and increasing production. Improvements due to optimization of waste throughput with increased HLW loading of the glass resulted in a 6% waste throughput increase based upon operational efficiencies. Improvements in canister production include the pour spout heated bellows liner (5%), glass surge (siphon) protection software (2%), melter feed pump software logic change to prevent spurious interlocks of the feed pump with subsequent dilution of feed stock (2%) and optimization of the steam atomized scrubber (SAS) operation to minimize downtime (3%) for a total increase in canister production of 12%. A number of process recovery efforts have allowed continued operation. These include the off gas system pluggage and restoration, slurry mix evaporator (SME) tank repair and replacement, remote cleaning of melter top head center nozzle, remote melter internal inspection, SAS pump J-Tube recovery, inadvertent pour scenario resolutions, dome heater transformer bus bar cooling water leak repair and new Infra-red camera for determination of glass height in the canister are discussed.

Odriscoll, R; Allan Barnes, A; Jim Coleman, J; Timothy Glover, T; Robert Hopkins, R; Dan Iverson, D; Jeff Leita, J

2008-01-15

330

Glucocorticoid-like effects of antihepatocarcinogen Rotenone are mediated via enhanced serum corticosterone levels: Molecular Fitting and Receptor Activation Studies  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Recent studies suggest that rotenone alters cell signal transduction pathways in a manner similar to glucocorticoids. Histological and biochemical markers of glucocorticoid effects in vivo, evaluated in our laboratories, provide further evidence for similarities in the activity of glucocorticoids and rotenone. The purpose of this study was to investigate the mechanism by which rotenone produces glucocorticoid-like effects. Methods Male B6C3F1 mice were treated for 7 days with rotenone (600 ppm in diet, the glucocorticoid antagonist RU486 (2 mg/kg/day, ip, corticosterone (2 mg/kg/day, ip, or both rotenone and RU 486. Control mice received drug-free diet and the vehicle (corn oil, ip. Following preservation in 10% neutral buffered formalin, tissues were embedded in paraffin. Sections were stained with hematoxylin, eosin, and were examined by light microscopy. Tissue sections were processed for in situ enzymatic end labeling of 3'-hydroxy-DNA strand breaks, a measure of apoptosis. Corticosterone was quantified in sera, using a solid phase radioimmunoassay kit. Cells (cell line 1470.2 derived from C127 mouse mammary adenocarcinoma cells were transiently transfected with 5 ?g of pLTRLuc and 1 ?g of ?-Galactosidase expression vectors using a BTX square-wave pulser at 155 V, 4 pulses (40 ms each. Cells were then treated with dexamethasone, rotenone, or a mixture of both for 6 hr, harvested and assayed for luciferase and ?-Galactosidase activity. Using Root Mean Square (RMS fit analysis (Alchemy™, Tripose, Inc., St Louis, MO, we assessed possible structural similarities between rotenone and corticosterone, dehydrocorticosterone, glucocorticoid antagonists ZK 98.299, and RU 486. RMS fit was calculated by selecting three atoms in each of the molecules, followed by calculating the distance between these atoms. An RMS value of zero between two molecules indicates identical molecular characteristics. A positive value suggests diminished similarity with a value of 1 or higher excluding any such similarities. Results Although the stimulatory effect exerted by rotenone on hepatocellular apoptosis was in the opposite direction of that produced by the glucocorticoid antagonist RU 486, data suggested that rotenone does not directly activate the glucocorticoid receptor. Molecular fitting of rotenone to glucocorticoid receptor agonists and antagonists as well as examination of the transcriptional activation of a glucocorticoid-responsive reporter gene (Mouse MammaryTumorVirus in response to rotenone indicated that it is highly unlikely that rotenone interacts directly with the glucocorticoid receptor. However, feeding male B6C3F1 mice a diet containing rotenone (600 ppm for 7 days resulted in a 3-fold increase in serum levels of corticosterone relative to control animals. Corticosterone is the major glucocorticoid in rodents. Conclusion Rotenone does not interact directly with the glucocorticoid receptor. Elevation of serum corticosterone levels in response to rotenone may explain the glucocorticoid-like effects of this compound, and may play a role in its anti-hepatocarcinogenic effect.

Youssef Jihan

2003-02-01

331

Femtosecond laser processing of germanium: an ab initio molecular dynamics study  

International Nuclear Information System (INIS)

An ab initio molecular dynamics study of femtosecond laser processing of germanium is presented in this paper. The method based on the finite temperature density functional theory is adopted to probe the structural change, thermal motion of the atoms, dynamic property of the velocity autocorrelation, and the vibrational density of states. Starting from a cubic system at room temperature (300 K) containing 64 germanium atoms with an ordered arrangement of 1.132 nm in each dimension, the femtosecond laser processing is simulated by applying a Nosé–Hoover thermostat to the electronic subsystem for ?100 fs and continuing with a microcanonical ensemble simulation of ?200 fs. The simulation results show solid, liquid and gas phases of germanium under adjusted intensities of the femtosecond laser irradiation. We find that the irradiated germanium is distinguishable from the usual germanium crystal by analysing their melting and dynamic properties. (paper)

332

Molecular dynamics simulations of solid-phase epitaxy of Si: Defect formation processes  

International Nuclear Information System (INIS)

We have investigated defect formation processes during solid-phase epitaxy of Si in the [001] direction based on molecular dynamics (MD) simulations using the Tersoff potential. Two different types of defect formation processes have been successfully observed in the MD simulations. They can be characterized by the structure of Si-Si dimer bonds created at the amorphous/crystalline interface in the initial stage of the defect formation. In the first type, the Si-Si dimer bonds form coupled dimer lines and these coupled dimer lines lead to the creation of {111} stacking faults. In the second type, the Si-Si dimer bonds form a single dimer line which leads to the creation of [111] twins

333

Wavelet analysis of molecular dynamics: Efficient extraction of time-frequency information in ultrafast optical processes  

Energy Technology Data Exchange (ETDEWEB)

New experimental techniques based on nonlinear ultrafast spectroscopies have been developed over the last few years, and have been demonstrated to provide powerful probes of quantum dynamics in different types of molecular aggregates, including both natural and artificial light harvesting complexes. Fourier transform-based spectroscopies have been particularly successful, yet “complete” spectral information normally necessitates the loss of all information on the temporal sequence of events in a signal. This information though is particularly important in transient or multi-stage processes, in which the spectral decomposition of the data evolves in time. By going through several examples of ultrafast quantum dynamics, we demonstrate that the use of wavelets provide an efficient and accurate way to simultaneously acquire both temporal and frequency information about a signal, and argue that this greatly aids the elucidation and interpretation of physical process responsible for non-stationary spectroscopic features, such as those encountered in coherent excitonic energy transport.

Prior, Javier; Castro, Enrique [Departamento de Física Aplicada, Universidad Politécnica de Cartagena, Cartagena 30202 (Spain); Chin, Alex W. [Theory of Condensed Matter Group, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Almeida, Javier; Huelga, Susana F.; Plenio, Martin B. [Institut für Theoretische Physik, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm (Germany)

2013-12-14

334

Wavelet analysis of molecular dynamics: Efficient extraction of time-frequency information in ultrafast optical processes  

International Nuclear Information System (INIS)

New experimental techniques based on nonlinear ultrafast spectroscopies have been developed over the last few years, and have been demonstrated to provide powerful probes of quantum dynamics in different types of molecular aggregates, including both natural and artificial light harvesting complexes. Fourier transform-based spectroscopies have been particularly successful, yet “complete” spectral information normally necessitates the loss of all information on the temporal sequence of events in a signal. This information though is particularly important in transient or multi-stage processes, in which the spectral decomposition of the data evolves in time. By going through several examples of ultrafast quantum dynamics, we demonstrate that the use of wavelets provide an efficient and accurate way to simultaneously acquire both temporal and frequency information about a signal, and argue that this greatly aids the elucidation and interpretation of physical process responsible for non-stationary spectroscopic features, such as those encountered in coherent excitonic energy transport

335

Induction and reversion process of molecular and cytological alterations after highly irradiated food ingestion in mice  

International Nuclear Information System (INIS)

The molecular and cytological alterations induced in a mammal (Mus musculus) fed ad libitum with a balanced pellet diet irradiated with 50 KGy gamma radiation from weaning, for different periods, are analyzed. The transient chromosomal changes that recall tumor-like phenomena could be the expression of the damage and repair processes induced by changed molecules present in irradiated food. The reversible alterations of DNA structure and cytoplasmatic soluble proteins observed in mice fed with irradiated pellet diet could be interpreted as a result of the enhancement of the repair processes which could also explain the significant increase of the radioresistance of DNA found at 200 days after irradiated food ingestion. Finally, our results would suggest an induction of a pseudo-neoplasia due to a prolongated and exclusive ingestion of food irradiated with sterilizing gamma dose. Moreover, the maintenance of the irradiated diet induce the reversion of the observed phenomena by an eventual activation of the repair mechanisms. (Author)

336

High-level waste processing at the Savannah River Site: An update  

International Nuclear Information System (INIS)

The Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) in Aiken, SC mg began immobilizing high-level radioactive waste in borosilicate glass in 1996. Currently, the radioactive glass is being produced as a ''sludge-only'' composition by combining washed high-level waste sludge with glass frit. The glass is poured in stainless steel canisters which will eventually be disposed of in a permanent, geological repository. To date, DWPF has produced about 100 canisters of vitrified waste. Future processing operations will, be based on a ''coupled'' feed of washed high-level waste sludge, precipitated cesium, and glass frit. This paper provides an update of the processing activities completed to date, operational/flowsheet problems encountered, and programs underway to increase production rates

337

Impact assessment of cadmium contamination on rice (Oryza sativa L.) seedlings at molecular and population levels using multiple biomarkers  

International Nuclear Information System (INIS)

Full text: Assessment of environmental contamination on ecology (plant) at molecular and population levels is important in risk quantification and remediation study. Random amplified polymorphic DNA (RAPD) assay and related other fingerprinting techniques have been employed to detect the genotoxin-induced DNA damage and mutations. This research compared the effects occurring at molecular and population levels in rice seedlings exposed to cadmium (Cd) concentrations of 15 - 60 mg L-1 for eight days with quartz sand culture. Inhibition of root growth and increase of total soluble protein content in root tips of rice seedlings were observed with the increase of Cd concentration. For the RAPD analyzes, 12 RAPD primers of 50 - 70 % GC content were found to produce unique polymorphic band patterns and subsequently were used to produce a total of 180 bands of 179 ? 3056 bp in molecular size in the control root tips of rice seedlings. Results produced by these RAPD primers indicate that changes in RAPD profiles of root tips after Cd treatment include modifications in band intensity and gain or loss of bands by comparison with control. The effect of changes was dose-dependent. Genomic template stability compares favourably with the traditional indices such as root growth and soluble protein content. The DNA polymorphisms detected by RAPD analysis can be applied as a suitable biomarker assay for the detection of genotoxic effects of Cd contamination on plants. (autects of Cd contamination on plants. (author)

338

Molecular dynamics simulation of the melting process in Ag27Cu13 core–shell nanoalloy  

International Nuclear Information System (INIS)

Highlights: • Melting process of Ag27Cu13 nanoalloy is studied by molecular dynamics simulation. • Different criteria are used to analyze thermal behavior of nanoalloy. • Steepest descent quenching method coupled to the isothermal MD simulations. • Multiple histogram method is used to remove the non-ergodicity problem. - Abstract: Molecular dynamics simulation in NVT ensemble coupled to steepest descent quenching method for studying melting mechanism of Ag27Cu13 nanoalloy, using thermodynamical, geometrical and dynamical criteria. Heat capacity values showed a strong fluctuation at temperatures of the phase coexistence region due to non-ergodicity in the simulation. Hence, in order to remove the non-ergodicity problem, multiple histogram method has been used. Heat capacity curve shows a shoulder peak at 620 K due to pre-melting of the surface atoms. Furthermore, at T = 840 K the melting behavior intensity of the atoms reaches to its maximum value, indicating that the melting process is completed. Considering the melting of 620 K for the nanoalloy, Lindemann parameter showed solid–solid isomerization at T = 480 K. Calculating ?shell and ?core proved that the corresponding solid–solid isomerization is only due to the shell atoms rearrangement. This fact is verified by quenching the configuration of the atoms by using steepest descent quenching method as well

339

Effect of water separation layer on metal nanoforming process investigated using molecular dynamics simulations  

Science.gov (United States)

The effects of water separation layer and temperature on the nanoforming process of Al films are studied using molecular dynamics simulations. These effects are evaluated in terms of molecular/atomic trajectories, potential energy, slip vectors, and the radial distribution function. The simulation results show that Al films can automatically fill cavities via heating without requiring an external loading exerted on them. At the complete filling stage, the most compact structure is obtained for forming with no water; however, the pattern collapses during the demolding process due to strong adhesion with the mold. In nanoforming in a humid environment, water molecules between the mold and Al film act as a buffer which relieves the forming pressure on the Al film, slowing down the deformation. During demolding, the buffer effectively prevents the formation of pattern defects induced by adhesion. Water molecules gradually vaporize with increasing temperature, which causes pattern failure due to a decrease in humidity. Moderate water layers are beneficial for better order and a compact pattern structure.

Wu, Cheng-Da; Chang Chin, Po-Yuan; Chiang, Chia-Chin; Lai, Rong-Jer; Fang, Te-Hua

2013-11-01

340

Recognition processes at a functionalized lipid surface observed with molecular resolution  

DEFF Research Database (Denmark)

The specific binding of proteins to functionalized lipid monolayers on aqueous subphases was characterized by neutron reflectivity and fluorescence microscopy measurements. Due to the high affinity and high specificity of their noncovalent interaction, streptavidin (SA) and biotin (vitamin H) were chosen as a model system to investigate the structural characteristics of a recognition process on a molecular length scale. Changes in the neutron reflection from the surfaces of NaCl aqueous (H2O or D2O) protein solutions (10(-8) M SA) were used to monitor the interaction of the protein with a monolayer of a biotinylated lipid in situ. Refinement of the reflectivity data and independent fluorescence microscopic observation of the interface using FITC-labeled SA showed that the protein forms macroscopically homogeneous (and presumably crystalline) domains covering a large portion of the surface. Moreover, the neutron reflection experiments clearly showed the formation of a monomolecular protein layer with an effective thickness, d(p) = 43.7 +/- 2 angstrom. The area per protein molecule occupied in the film was A0 = 2860 +/- 200 angstrom 2 and n(w) = 260 +/- 100 water molecules were associated with each protein molecule. Quantitative binding was found to occur at biotin surface concentrations as low as 1 molecule/1,250 angstrom 2 (compared with approximately 1 molecule/40 angstrom 2 for dense packing). This study demonstrates the application of a promising new tool for the systematic investigation of molecular recognition processes in protein/lipid model systems.

Vaknin, D.; Als-Nielsen, J.

1991-01-01

341

Neitron scattering on molecular crystals with a high level of optical pumping of excitons  

International Nuclear Information System (INIS)

Scattering of neutrons in molecular crystals in the presence of a high exciton concentration is considered theoretically. Two possible channels of scattering by excitons are investigated: magnetic scattering by triplet excitons and nuclear scattering. It is demonstrated that as a result of excitation correlation a change in the nuclear configurations of the molecules in electron excitation leads to the appearance of an additional channel of nuclear inelastic scattering. Scattering of neutrons by a system of high exciton density is considered by taking into account dynamic and kinematic exciton-exciton interactions. Some characteristics of inelastic neutron scattering in the presence of a bose condensate of the molecular excitons are considered. Exciton production on inelastic scattering of neutrons caused by exciton-phonon interaction is investigated. The formulae derived are in agreement with the known results

342

Endogenous testosterone levels are associated with neural activity in men with schizophrenia during facial emotion processing.  

Science.gov (United States)

Growing evidence suggests that testosterone may play a role in the pathophysiology of schizophrenia given that testosterone has been linked to cognition and negative symptoms in schizophrenia. Here, we determine the extent to which serum testosterone levels are related to neural activity in affective processing circuitry in men with schizophrenia. Functional magnetic resonance imaging was used to measure blood-oxygen-level-dependent signal changes as 32 healthy controls and 26 people with schizophrenia performed a facial emotion identification task. Whole brain analyses were performed to determine regions of differential activity between groups during processing of angry versus non-threatening faces. A follow-up ROI analysis using a regression model in a subset of 16 healthy men and 16 men with schizophrenia was used to determine the extent to which serum testosterone levels were related to neural activity. Healthy controls displayed significantly greater activation than people with schizophrenia in the left inferior frontal gyrus (IFG). There was no significant difference in circulating testosterone levels between healthy men and men with schizophrenia. Regression analyses between activation in the IFG and circulating testosterone levels revealed a significant positive correlation in men with schizophrenia (r=.63, p=.01) and no significant relationship in healthy men. This study provides the first evidence that circulating serum testosterone levels are related to IFG activation during emotion face processing in men with schizophrenia but not in healthy men, which suggests that testosterone levels modulate neural processes relevant to facial emotion processing that may interfere with social functioning in men with schizophrenia. PMID:25796490

Ji, Ellen; Weickert, Cynthia Shannon; Lenroot, Rhoshel; Catts, Stanley V; Vercammen, Ans; White, Christopher; Gur, Raquel E; Weickert, Thomas W

2015-06-01

343

Review process of PSA level 2 of KBR - Concept and Experience  

International Nuclear Information System (INIS)

In Germany, a periodic safety review (PSR) has to be performed every ten years by the utility. In the past, a PSR only included a plant-specific probabilistic safety analysis (PSA) Level 1 study. Since a revised version of the German PSA guideline has been released in 2005, these plant-specific PSAs have to include a PSA Level 2, too. For the NPP Brokdorf (KBR) PSA Level 2 project, an agreement was reached between all parties involved that the study will be performed not as a part of the PSR process, but supplementary to it. This paper will focus on conclusions and findings from an ongoing parallel review process of the first full scope PSA Level 2 performed by the utility for KBR, a typical German PWR-1300. The responsible authority 'Ministerium fuer Soziales, Gesundheit, Familie, Jugend und Senioren des Landes Schleswig- Holstein' (MSGF) initiated this parallel review process in agreement with the utility KBR and the E.ON Kernkraft in 2006. The project will be completed soon. Such a review process allows that essential steps of the PSA will be reviewed and commented before the PSA Level 2 will be finished. So the benefit from this parallel review process is a significant enhancement of the quality and completeness of the PSA Level 2 study as the majority of the recommendations given by the review team has been taken over by the utility and the developer of the PSA, the AREVA NP company. Further, a common understanding and agreement will be reached at the end betweenreement will be reached at the end between all parties involved on the major topics of the PSA Level 2 study. The paper is followed by the slides of the presentation. (authors)

344

Vapor pressure dependence of spectral width of EIT in Lambda-level cesium molecular system  

CERN Document Server

We have studied electromagnetically induced transparency (EIT) in diatomic cesium molecules in a vapor cell by using tunable diode lasers. We have observed a sub-natural Lambda-resonance in an absorption molecular band at different cesium vapor pressures. The width of the EIT resonance shows a linear dependence on cesium vapor pressure. Narrow Lambda-resonances in molecules can be used as frequency references for femtosecond laser frequency combs.

Chen, Hui; Rostovtsev, Yuri V; Gubin, Mikhail A; Sautenkov, Vladimir A; Scully, Marlan O

2009-01-01

345

Molecular Biology at the Quantum Level: Can Modern Density Functional Theory Forge the Path?  

OpenAIRE

Recent years have seen vast improvements in the ability of rigorous quantum-mechanical methods to treat systems of interest to molecular biology. In this review article, we survey common computational methods used to study such large, weakly bound systems, starting from classical simulations and reaching to quantum chemistry and density functional theory. We sketch their underlying frameworks and investigate their strengths and weaknesses when applied to potentially large bi...

Kolb, Brian; Thonhauser, T.

2012-01-01

346

Sigma Level Performance of the Innovated Process in the Imaging Department at a Mexican Health Institute  

OpenAIRE

The National Institute of Respiratory Diseases is a third level public hospital in Mexico City, which in 2007 acquired an RIS-PACS to be implemented at its Imaging Department (ID), with the objective to enhance its service. This department attends an average of 3,500 patients per month developing different image modalities. The objective of this work was to determine the overall sigma level performance of four processes of the ID: reception, X-ray, computed tomography, and radiologist diagnos...

Garci?a-porres, Julieta; Ortiz-posadas, Martha R.

2012-01-01

347

Correlation test to assess low-level processing of high-density oligonucleotide microarray data  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background There are currently a number of competing techniques for low-level processing of oligonucleotide array data. The choice of technique has a profound effect on subsequent statistical analyses, but there is no method to assess whether a particular technique is appropriate for a specific data set, without reference to external data. Results We analyzed coregulation between genes in order to detect insufficient normalization between arrays, where coregulation is measured in terms of statistical correlation. In a large collection of genes, a random pair of genes should have on average zero correlation, hence allowing a correlation test. For all data sets that we evaluated, and the three most commonly used low-level processing procedures including MAS5, RMA and MBEI, the housekeeping-gene normalization failed the test. For a real clinical data set, RMA and MBEI showed significant correlation for absent genes. We also found that a second round of normalization on the probe set level improved normalization significantly throughout. Conclusion Previous evaluation of low-level processing in the literature has been limited to artificial spike-in and mixture data sets. In the absence of a known gold-standard, the correlation criterion allows us to assess the appropriateness of low-level processing of a specific data set and the success of normalization for subsets of genes.

Bergh Jonas

2005-03-01

348

Evaluation of high-level waste pretreatment processes with an approximate reasoning model  

International Nuclear Information System (INIS)

The development of an approximate-reasoning (AR)-based model to analyze pretreatment options for high-level waste is presented. AR methods are used to emulate the processes used by experts in arriving at a judgment. In this paper, the authors first consider two specific issues in applying AR to the analysis of pretreatment options. They examine how to combine quantitative and qualitative evidence to infer the acceptability of a process result using the example of cesium content in low-level waste. They then demonstrate the use of simple physical models to structure expert elicitation and to produce inferences consistent with a problem involving waste particle size effects

349

Evaluation of high-level waste pretreatment processes with an approximate reasoning model  

Energy Technology Data Exchange (ETDEWEB)

The development of an approximate-reasoning (AR)-based model to analyze pretreatment options for high-level waste is presented. AR methods are used to emulate the processes used by experts in arriving at a judgment. In this paper, the authors first consider two specific issues in applying AR to the analysis of pretreatment options. They examine how to combine quantitative and qualitative evidence to infer the acceptability of a process result using the example of cesium content in low-level waste. They then demonstrate the use of simple physical models to structure expert elicitation and to produce inferences consistent with a problem involving waste particle size effects.

Bott, T.F.; Eisenhawer, S.W.; Agnew, S.F.

1999-04-01

350

Process for measuring low cadmium levels in blood and other biological specimens  

Science.gov (United States)

A process for measuring low levels of cadmium in blood and other biological specimens is provided without interference from high levels of alkali metal contaminants by forming an aqueous solution and without contamination by environmental cadmium absent the proteins from the specimen, selectively removing cadmium from the aqueous solution on an anion exchange resin, thereby removing the alkali metal contaminants, resolubilizing cadmium from the resin to form a second solution and analyzing the second solution for cadmium, the process being carried out in a cadmium-free environment.

Peterson, David P. (Orland Park, IL); Huff, Edmund A. (Lemont, IL); Bhattacharyya, Maryka H. (Naperville, IL)

1994-01-01

351

Study on the toxic interaction of methanol, ethanol and propanol against the bovine hemoglobin (BHb) on molecular level  

Science.gov (United States)

The toxic interaction of methanol, ethanol and propanol with bovine hemoglobin (BHb) at protein molecular level was studied by resonance light scattering (RLS), fluorescence, ultraviolet-visible absorption (UV-vis) and circular dichroism (CD) techniques. The experimental results showed that the three alcohols all had toxic effects on BHb and the effects increased along with the increasing alcohol dose. The results of RLS and fluorescence spectroscopy showed that alcohols can denature BHb. They changed the microenvironment of amino acid residues and led to molecular aggregation. The decreasing order of the influence is propanol, ethanol and methanol. The results of UV-vis and CD spectra revealed that alcohols led to conformational changes of BHb, including the loosening of the skeleton structure and the decreasing of ?-helix in the second structure. The changes generated by propanol were much larger than those by methanol and ethanol.

Jun, Chai; Xue, Yan; Liu, Rutao; Wang, Meijie

2011-09-01

352

Dynamics of cooperative emissions in a cascade three-level molecular system driven by an ultrashort laser pulse  

International Nuclear Information System (INIS)

This paper investigates the dynamics of cooperative emissions in a cascade three-level system driven by an ultrashort laser pulse by solving numerically the full-wave Maxwell–Bloch equations. The 4, 4'-bis(dimethylamino) stilbene molecule is used as the model molecule because of its strong two-photon absorption property. The two-colour cooperative emissions are studied as functions of molecular number density and dephasing rate of the dipole coherence. The propagation effects on the evolution of the cooperative radiations are also taken into account. The cooperative radiations are enhanced for large number density of the molecule, while the fast dephasing of the dipole coherence reduces the intensity of the cooperative radiations and delays the emission times or even inhibits the formation of the emissions. The delay time of the radiation decreases with the increase of the molecular number density and the propagation distance. (classical areas of phenomenology)

353

Characterization of deep acceptor level in as-grown ZnO thin film by molecular beam epitaxy  

Science.gov (United States)

We report deep level transient spectroscopy results from ZnO layers grown on silicon by molecular beam epitaxy (MBE). The hot probe measurements reveal mixed conductivity in the as-grown ZnO layers, and the current—voltage (I—V) measurements demonstrate a good quality p-type Schottky device. A new deep acceptor level is observed in the ZnO layer having activation energy of 0.49 ±0.03 eV and capture cross-section of 8.57 × 10-18 cm2. Based on the results from Raman spectroscopy, photoluminescence, and secondary ion mass spectroscopy (SIMS) of the ZnO layer, the observed acceptor trap level is tentatively attributed to a nitrogen-zinc vacancy complex in ZnO.

Asghar, M.; K., Mahmood; A. Hasan, M.; T. Ferguson, I.; Tsu, R.; Willander, M.

2014-09-01

354

Cilnidipine regulates glucose metabolism and levels of high-molecular adiponectin in diet-induced obese mice.  

Science.gov (United States)

The aim of the present study is to examine the effects of the antihypertensive drug cilnidipine on glucose metabolism and adipocytokines, including adiponectin, in diet-induced obese (DIO) mice. The effects of cilnidipine on insulin sensitivity and the levels of adiponectin in DIO mice were examined after the mice had been treated with cilnidipine dissolved in water at a dose of 0.2?g?l(-1) for 14 days. As expected, treatment with cilnidipine decreased the systolic and diastolic blood pressures in DIO mice, compared with control mice (PCilnidipine treatment improved glucose and insulin sensitivity in DIO mice. In addition, cilnidipine treatment dramatically increased the level of adiponectin in white adipose tissue (Pcilnidipine treatment. Finally, the secretion of adiponectin from adipocytes was increased after cilnidipine treatment. Taken together, these results indicate that cilnidipine improves insulin tolerance and adiponectin levels, especially high-molecular type adiponectin, in DIO mice. PMID:23051658

Ueno, Daisuke; Masaki, Takayuki; Gotoh, Koto; Chiba, Seiichi; Kakuma, Tetsuya; Yoshimatsu, Hironobu

2013-03-01

355

Planning and organization of the learning process in art education at primary level  

OpenAIRE

Planning and organization in any learning process is difficult. It consists of accepted curriculum, organization of the school and local community. In what extent and how the teachers will implement formal directions into the classroom planning, depends on the teacher as the individual and his planning of the pedagogical process. (Uljens, 1997) Theoretical part of the thesis will present education at primary level in the Republic of Slovenia. It will present the documents in primary school...

Jakopin, Nives

2011-01-01

356

Natural Language Processing Technologies for Multi-Level Intelligent Spam Mail-Filter  

OpenAIRE

To overcome the lack of existing mail filtering system, we designed a content-based message filtering system of multi-level intelligence. Using natural language processing technology, it denotes the E-mail content including attachments. First, it pre-processes the content of E-mail, including segmentation, feature extraction. Second, combining knowledge-base and expansion of the feature, it can form the vector. Corresponding categories vector in the database, two vectors similar degree of cal...

Haiyan; Xiaojiao

2014-01-01

357

Process technology for vitrification of defense high-level waste at the Savannah River Plant  

International Nuclear Information System (INIS)

Vitrification in borosilicate glass is now the leading worldwide process for immobilizing high-level radioactive waste. Each vitrification project, however, has its unique mission and technical challenges. The Defense Waste Vitrification Facility (DWPF) now under construction at the Savannah River Plant will concentrate and vitrify a large amount of relatively low-power alkaline waste. Process research and development for the DWPF have produced significant advances in remote chemical operations, glass melting, off-gas treatment, slurry handling, decontamination, and welding

358

Product and Process Innovation and the Decision to Export: Firm-level Evidence for Belgium  

OpenAIRE

Using data from the Community Innovation Survey for Belgium in two consecutive periods, this paper explores the relationship between firm-level innovation activities and the propensity to start exporting. To measure innovation, we include indicators of both innovative effort (R&D activities) as well as innovative output (product and process innovation). Our results suggest that the combination of product and process innovation, rather than either of the two in isolation, increases a firm's pr...

Beveren, Ilke; Vandenbussche, Hylke

2009-01-01

359

Productivity effects of business process outsourcing: a firm-level investigation based on panel data  

OpenAIRE

This paper analyses the impact of business process outsourcing (BPO) on firm productivity based on a comprehensive German firm-level panel data set covering manufacturing and service industries. The growing importance of service inputs into the production process is undisputed. Firms increasingly buy all or at least parts of selected services they need from external service providers. This is especially true for services which rely to a great extent on new information and communication techno...

Ohnemus, Jo?rg

2009-01-01

360

Productivity Effects of Business Process Outsourcing - A Firm-level Investigation Based on Panel Data  

OpenAIRE

This paper analyses the impact of business process outsourcing (BPO) on firm productivity based on a comprehensive German firm-level panel data set covering manufacturing and service industries. The growing importance of service inputs into the production process is undisputed. Firms increasingly buy all or at least parts of selected services they need from external service providers. This is especially true for services which rely to a great extent on new information and communication techno...

Ohnemus, Jo?rg

2010-01-01

361

Emotional face processing in women with high and low levels of eating disorder related symptoms.  

OpenAIRE

OBJECTIVES: Emotional processing has rarely been investigated in those "at risk" of developing an eating disorder. This study investigated the processing of six basic emotions depicted on faces in an "at risk" group, compared to a control group. DESIGN: Participants were women with high (N=29) and low (N=23) levels of eating disorder symptoms who were not taking psychotropic medication. A well characterised computerised task (Facial Expression Emotion Task) was administered to all participant...

Jones, L.; Harmer, C.; Cowen, P.; Cooper, M.

2008-01-01

362

ARTICLE Molecular Dynamic Simulation on the Absorbing Process of Isolating and Coating of ?-olefin Drag Reducing Polymer  

Science.gov (United States)

The absorbing process in isolating and coating process of ?-olefin drag reducing polymer was studied by molecular dynamic simulation method, on basis of coating theory of ?-olefin drag reducing polymer particles with polyurethane as coating material. The distributions of sodium laurate, sodium dodecyl sulfate, and sodium dodecyl benzene sulfonate on the surface of ?-olefin drag reducing polymer particles were almost the same, but the bending degrees of them were obviously different. The bending degree of SLA molecules was greater than those of the other two surfactant molecules. Simulation results of absorbing and accumulating structure showed that, though hydrophobic properties of surfactant molecules were almost the same, water density around long chain sulfonate sodium was bigger than that around alkyl sulfate sodium. This property goes against useful absorbing and accumulating on the surface of ?-olefin drag reducing polymer particles; simulation results of interactions of different surfactant and multiple hydroxyl compounds on surface of particles showed that, interactions of different surfactant and one kind of multiple hydroxyl compound were similar to those of one kind of surfactant and different multiple hydroxyl compounds. These two contrast types of interactions also exhibited the differences of absorbing distribution and closing degrees to surface of particles. The sequence of closing degrees was derived from simulation; control step of addition polymerization interaction in coating process was absorbing mass transfer process, so the more closed to surface of particle the multiple hydroxyl compounds were, the easier interactions with isocyanate were. Simulation results represented the compatibility relationship between surfactant and multiple hydroxyl compounds. The isolating and coating processes of ?-olefin drag reducing polymer were further understood on molecule and atom level through above simulation research, and based on the simulation, a referenced theoretical basis was provided for practical optimal selection and experimental preparation of ?-olefin drag reducing polymer particles suspension isolation agent.

Li, Bing; Sheng, Xiang; Xing, Wen-guo; Dong, Gui-lin; Liu, Yong-jun; Zhang, Chang-qiao; Chen, Xiang-jun; Zhou, Ning-ning; Qin, Zhan-bo

2010-12-01

363

Ceramic process and plant design for high-level nuclear waste immobilization  

International Nuclear Information System (INIS)

In the last 3 years, significant advances in ceramic technology for high-level nuclear waste solidification have been made. Product quality in terms of leach-resistance, compositional uniformity, structural integrity, and thermal stability promises to be superior to borosilicate glass. This paper addresses the process effectiveness and preliminary designs for glass and ceramic immobilization plants. The reference two-step ceramic process utilizes fluid-bed calcination (FBC) and hot isostatic press (HIP) consolidation. Full-scale demonstration of these well-developed processing steps has been established at DOE and/or commercial facilities for processing radioactive materials. Based on Savannah River-type waste, our model predicts that the capital and operating cost for the solidification of high-level nuclear waste is about the same for the ceramic and glass options. However, when repository costs are included, the ceramic option potentially offers significantly better economics due to its high waste loading and volume reduction. Volume reduction impacts several figures of merit in addition to cost such as system logistics, storage, transportation, and risk. The study concludes that the ceramic product/process has many potential advantages, and rapid deployment of the technology could be realized due to full-scale demonstrations of FBC and HIP technology in radioactive environments. Based on our finding and those of others, the ceramic innovation not only offers a viable backup to the glass reference process but promises to be a viable future option for new high-level nuclear waste management opportunities

364

Sources and processes affecting levels and composition of atmospheric particulate matter in the Western Mediterranean  

OpenAIRE

This study is focused on the identification of the sources and processes affecting levels and composition of PM10 and PM2.5 from air quality monitoring networks in Eastern Spain. This is a multidisciplinary study. Time series of TSP and PM10 recorded from 1996 to 2000 are interpreted to assess the role of local, regional and distant sources in PM levels in this region. To this is end, the influence of the meteorology on PM levels recorded at nineteen rural, urban and industrial monitoring sta...

Rodri?guez Gonza?lez, Sergio

2002-01-01

365

A regional low-level waste management system: the siting process  

International Nuclear Information System (INIS)

The Rocky Mountain Low-Level Radioactive Waste Compact has been developed for the purpose of managing low-level radioactive waste generated in the region, comprised of the States of Arizona, Colorado, Nevada, New Mexico, Utah and Wyoming. The Compact calls for the region's largest generating states to host the Compact's low-level waste management facilities. In recognition of its responsibility to host such a facility, the State of Colorado has instituted a siting process for the purpose of establishing a low-level waste disposal facility to serve the region. The efficacy of this siting system is now being tested by the silting and facility development activities of a low-level waste disposal company

366

Mechanical properties and biocompatibility of melt processed, self-reinforced ultrahigh molecular weight polyethylene.  

Science.gov (United States)

The low efficiency of fabrication of ultrahigh molecular weight polyethylene (UHMWPE)-based artificial knee joint implants is a bottleneck problem because of its extremely high melt viscosity. We prepared melt processable UHMWPE (MP-UHMWPE) by addition of 9.8 wt% ultralow molecular weight polyethylene (ULMWPE) as a flow accelerator. More importantly, an intense shear flow was applied during injection molding of MP-UHMWPE, which on one hand, promoted the self-diffusion of UHMWPE chains, thus effectively reducing the structural defects; on the other hand, increased the overall crystallinity and induced the formation of self-reinforcing superstructure, i.e., interlocked shish-kebabs and oriented lamellae. Aside from the good biocompatibility, and the superior fatigue and wear resistance to the compression-molded UHMWPE, the injection-molded MP-UHMWPE exhibits a noteworthy enhancement in tensile properties and impact strength, where the yield strength increases to 46.3 ± 4.4 MPa with an increment of 128.0%, the ultimate tensile strength and Young's modulus rise remarkably up to 65.5 ± 5.0 MPa and 1248.7 ± 45.3 MPa, respectively, and the impact strength reaches 90.6 kJ/m(2). These results suggested such melt processed and self-reinforced UHMWPE parts hold a great application promise for use of knee joint implants, particularly for younger and more active patients. Our work sets up a new method to fabricate high-performance UHMWPE implants by tailoring the superstructure during thermoplastic processing. PMID:24835044

Huang, Yan-Fei; Xu, Jia-Zhuang; Li, Jian-Shu; He, Ben-Xiang; Xu, Ling; Li, Zhong-Ming

2014-08-01

367

Continuum level treatment of electronic polarization in the framework of molecular simulations of solvation effects  

International Nuclear Information System (INIS)

The hybrid molecular-continuum model for polar solvation considered in this paper combines the dielectric continuum approximation for treating fast electronic (inertialess) polarization effects and a molecular dynamics (MD) simulation for the slow (inertial) polarization component, including orientational and translational solvent modes. The inertial polarization is generated by average charge distributions of solvent particles, composed of permanent and induced (electronic) components. MD simulations are performed in a manner consistent with the choice of solvent and solute charges such that all electrostatic interactions are scaled by the factor 1/??, where ?? is the optical dielectric permittivity. This approach yields an ensemble of equilibrium solvent configurations adjusted to the electric field created by a charged or strongly polar solute. The electrostatic solvent response field is found as the solution of the Poisson equation including both solute and explicit solvent charges, with accurate account of electrostatic boundary conditions at the surfaces separating spatial regions with different dielectric permittivities. Both equilibrium and nonequilibrium solvation effects can be studied by means of this model, and their inertial and inertialess contributions are naturally separated. The methodology for computation of charge transfer reorganization energies is developed and applied to a model two-site dipolar system in the SPC watersite dipolar system in the SPC water solvent. Three types of charge transfer reactions are considered. The standard linear-response approach yields high accuracy for each particular reaction, but proves to be significantly in error when reorganization energies of different reactions were compared. This result has a purely molecular origin and is absent within a conventional continuum solvent model

368

Characterization of the breakpoints of a polymorphic inversion complex detects strict and broad breakpoint reuse at the molecular level.  

Science.gov (United States)

Inversions are an integral part of structural variation within species, and they play a leading role in genome reorganization across species. Work at both the cytological and genome sequence levels has revealed heterogeneity in the distribution of inversion breakpoints, with some regions being recurrently used. Breakpoint reuse at the molecular level has mostly been assessed for fixed inversions through genome sequence comparison, and therefore rather broadly. Here, we have identified and sequenced the breakpoints of two polymorphic inversions-E1 and E2 that share a breakpoint-in the extant Est and E1 + 2 chromosomal arrangements of Drosophila subobscura. The breakpoints are two medium-sized repeated motifs that mediated the inversions by two different mechanisms: E1 via staggered breaks and subsequent repair and E2 via repeat-mediated ectopic recombination. The fine delimitation of the shared breakpoint revealed its strict reuse at the molecular level regardless of which was the intermediate arrangement. The occurrence of other rearrangements in the most proximal and distal extended breakpoint regions reveals the broad reuse of these regions. This differential degree of fragility might be related to their sharing the presence outside the inverted region of snoRNA-encoding genes. PMID:24881049

Puerma, Eva; Orengo, Dorcas J; Salguero, David; Papaceit, Montserrat; Segarra, Carmen; Aguadé, Montserrat

2014-09-01

369

High level model predictive control for plug-and-play process control with stability guaranty  

DEFF Research Database (Denmark)

In this paper a method for designing a stabilizing high level model predictive controller for a hierarchical plug- and-play process is presented. This is achieved by abstracting the lower layers of the controller structure as low order models with uncertainty and by using a robust model predictive controller for generating the references for these. A simulation example, in which the actuators in a process control system are changed, is reported to show the potential of this approach for plug and play process control.

Michelsen, Axel Gottlieb; Stoustrup, Jakob

2010-01-01

370

High level nuclear waste treatment in the Defense Waste Processing Facility: Overview and integrated flowsheet model  

International Nuclear Information System (INIS)

Design and construction of the world's largest vitrification facility for high level nuclear waste has been nearly completed at the US Department of Energy's Savannah River Site. Equipment testing and calibration are currently being performed in preparation for the nonradioactive Chemical Runs in the late 1991. In 1993, the Defense Waste Processing Facility (DWPF) will begin producing 100 kg/hr of radioactive waste glass at 28 wt% waste oxide loading. This paper describes all phases of waste processing operations in DWPF and waste tank farms using the integrated flowsheet modeling approach. Particular emphases are given to recent developments in the DWPF processes and design

371

Geometric Phase in a Two Energy Level Jaynes-Cummings Model with Imaginary Photon Process  

Science.gov (United States)

By using the Lewis-Riesenfeld invariant theory, we have studied the dynamical and the geometric phases in a two energy level Jaynes-Cummings model with imaginary photon process. We find that the geometric phases in a cycle case have nothing to do with the frequency of the photon field, the coupling coefficient between photons and atoms, and the atom transition frequency. If we use the more accuracy device, the geometric phases in the imaginary photon process may be observed, and the geometric phases in this process have the observable physical effect.

Yu, Ge; Yu, Zhao-Xian; Jiao, Zhi-Yong; Xie, Bing-Hao; Jin, Shuo

2008-09-01

372

Nonlinear Microrheology Reveals Entanglement-Driven Molecular-Level Viscoelasticity of Concentrated DNA  

Science.gov (United States)

We optically drive a trapped microscale probe through entangled DNA at rates up to 100× the disentanglement rate (Wi ?100), then remove the trap and track subsequent probe recoil motion. We identify a unique crossover to the nonlinear regime at Wi ?20. Recoil dynamics display rate-dependent dilation and complex power-law healing of the reptation tube. The force response during strain exhibits key nonlinear features such as shear thinning and yielding with power-law rate dependence. Our results, distinctly nonclassical and in accord with recent theoretical predictions, reveal molecular dynamics governed by individual stress-dependent entanglements rather than chain stretching.

Chapman, Cole D.; Robertson-Anderson, Rae M.

2014-08-01

373

Gene Expression Profiles of the NCI-60 Human Tumor Cell Lines Define Molecular Interaction Networks Governing Cell Migration Processes  

OpenAIRE

Although there is extensive information on gene expression and molecular interactions in various cell types, integrating those data in a functionally coherent manner remains challenging. This study explores the premise that genes whose expression at the mRNA level is correlated over diverse cell lines are likely to function together in a network of molecular interactions. We previously derived expression-correlated gene clusters from the database of the NCI-60 human tumor cell lines and assoc...

Kohn, Kurt W.; Zeeberg, Barry R.; Reinhold, William C.; Sunshine, Margot; Luna, Augustin; Pommier, Yves

2012-01-01

374

Application of the activation process model to the molecules, positive molecular ions, clusters, and proteins surrounded of IR laser radiation  

Science.gov (United States)

In 1990 the activation process model was proposed [1]. Development of the activation process model [2,3] led to description of either adiabatic or non-adiabatic processes for a molecular structure transformation [4]. The model is based on two simple assumptions: 1. During the transformation process, the potential energy of a molecular particle changes discretely or in quanta: the transformation process appears to be a series of quantum subsystems occurring in sequence (these subsystems may also be defined as identical quantum oscillators); 2. In the field of IR-laser radiation, an energy exchange between IR radiation and atoms of the molecular particle results in discrete translation of these atoms which absorb oscillation energy by identical quanta up to molecular structure complete transformation. The numerical simulation carried out according to the model offered has allowed to describe such processes as: dissociation of SF6 molecule [4] and styrene ion C 8H 8 + [5]; selfdiffusion processes in Si, Ge and GaAs clusters [6]; folding and insertion for the ?-barrel outer membrane protein A (OmpA) of Escherichia coli into dioleoylphosphatidylcholine (DOPC) bilayers [7]. So, we can see this model has a significant field of application to the activation processes stimulated by IR laser radiation.

Stepanov, Anatoly V.

2007-06-01

375

Bidirectional connectivity between hemispheres occurs at multiple levels in language processing but depends on sex.  

Science.gov (United States)

Our aim was to determine the direction of interhemispheric communication in a phonological task in regions involved in different levels of processing. Effective connectivity analysis was conducted on functional magnetic resonance imaging data from 39 children (ages 9-15 years) performing rhyming judgment on spoken words. The results show interaction between hemispheres at multiple levels. First, there is unidirectional transfer of information from right to left at the sensory level of primary auditory cortex. Second, bidirectional connections between superior temporal gyri (STGs) suggest a reciprocal cooperation between hemispheres at the level of phonological and prosodic processing. Third, a direct connection from right STG to left inferior frontal gyrus suggest that information processed in the right STG is integrated into the final stages of phonological segmentation required for the rhyming decision. Intrahemispheric connectivity from primary auditory cortex to STG was stronger in the left compared to the right hemisphere. These results support a model of cooperation between hemispheres, with asymmetric interhemispheric and intrahemispheric connectivity consistent with the left hemisphere specialization for phonological processing. Finally, we found greater interhemispheric connectivity in girls compared to boys, consistent with the hypothesis of a more bilateral representation of language in females than males. However, interhemispheric communication was associated with slow performance and low verbal intelligent quotient within girls. We suggest that females may have the potential for greater interhemispheric cooperation, which may be an advantage in certain tasks. However, in other tasks too much communication between hemispheres may interfere with task performance. PMID:20810879

Bitan, Tali; Lifshitz, Adi; Breznitz, Zvia; Booth, James R

2010-09-01

376

Greater-than-class C low-level waste characterization technical review process  

International Nuclear Information System (INIS)

The objective of this paper is to present the technical review process that has been used to complete projections of commercial Greater-Than-Class C low-level waste (GTCC LLW). Accurate projections are necessary in order to support planning for management of GTCC LLW, including storage, treatment, and disposal. The projections include estimates of volumes, activities, radionuclides, waste generators, and waste types

377

The influence of deck storage and initial processing on patulin levels in apple juice.  

Science.gov (United States)

Patulin, a secondary metabolite produced by Penicillium expansum and some other fungal species, is a common contaminant of ripened apples used for the production of apple juice concentrates. The limited availability of suitable storage facilities may result in fruit being subjected to storage in the open ('deck storage') for extended periods of time, prior to processing. A study was conducted to determine the influence that deck storage and subsequent initial processing practices had on patulin levels in freshly pressed juice. Over the study period, triplicate samples were collected at four strategic processing points from individual consignments of Granny Smith apples deck-stored for 7, 15 and 33 days, respectively. Over the study period, mean patulin levels in non-processed fruit increased from 90 to 2445 ng/g, respectively, but decreased to between 75 and 695 ng/g, respectively, following a water wash step. Subsequent removal of rotten/damaged fruit decreased patulin levels further (to between 55 and 405 ng/g, respectively), although the numerical decreases between sampling points were not shown to be statistically significant (P > 0.05). However, patulin levels were significantly higher (P juice samples. The mycological analyses tended to support the chemical data, in that removal of the rotten/damaged fractions significantly reduced total fungal counts in the juice samples. PMID:9328526

Sydenham, E W; Vismer, H F; Marasas, W F; Brown, N L; Schlechter, M; Rheeder, J P

1997-07-01

378

Levels of Description in Consonant/Vowel Processing: Reply to Knobel and Caramazza  

Science.gov (United States)

Is it necessary to posit separate, explicit distinctions between representations in order to account for dissociations between consonant and vowel processing? We argue that a cognitive model of speech production based on cumulative lower-level properties is not only sufficient but more parsimonious in accounting for aphasic and dysgraphic patient…

Monaghan, Padraic; Shillcock, Richard

2007-01-01

379

Internet Access, Use and Sharing Levels among Students during the Teaching-Learning Process  

Science.gov (United States)

The purpose of this study was to determine the awareness among students and levels regarding student access, use, and knowledge sharing during the teaching-learning process. The triangulation method was utilized in this study. The population of the research universe was 21,747. The student sample population was 1,292. Two different data collection…

Tutkun, Omer F.

2011-01-01

380

Molecular reordering processes on ice (0001) surfaces from long timescale simulations  

Science.gov (United States)

We report results of long timescale adaptive kinetic Monte Carlo simulations aimed at identifying possible molecular reordering processes on both proton-disordered and ordered (Fletcher) basal plane (0001) surfaces of hexagonal ice. The simulations are based on a force field for flexible molecules and span a time interval of up to 50 ?s at a temperature of 100 K, which represents a lower bound to the temperature range of earth's atmosphere. Additional calculations using both density functional theory and an ab initio based polarizable potential function are performed to test and refine the force field predictions. Several distinct processes are found to occur readily even at this low temperature, including concerted reorientation (flipping) of neighboring surface molecules, which changes the pattern of dangling H-atoms, and the formation of interstitial defects by the downwards motion of upper-bilayer molecules. On the proton-disordered surface, one major surface roughening process is observed that significantly disrupts the crystalline structure. Despite much longer simulation time, such roughening processes are not observed on the highly ordered Fletcher surface which is energetically more stable because of smaller repulsive interaction between neighboring dangling H-atoms. However, a more localized process takes place on the Fletcher surface involving a surface molecule transiently leaving its lattice site. The flipping process provides a facile pathway of increasing proton-order and stabilizing the surface, supporting a predominantly Fletcher-like ordering of low-temperature ice surfaces. Our simulations also show that eventual proton-disordered patches on the surface may induce significant local reconstructions. Further, a subset of the molecules on the Fletcher surface are susceptible to forming interstitial defects which might provide active sites for various chemical reactions in the atmosphere.

Pedersen, Andreas; Wikfeldt, Kjartan T.; Karssemeijer, Leendertjan; Cuppen, Herma; Jónsson, Hannes

2014-12-01

381

Towards understanding the molecular recognition process in prokaryotic zinc-finger domain.  

Science.gov (United States)

Eukaryotic Cys2His2 zinc finger domain is one of the most common and important structural motifs involved in protein-DNA interaction. The recognition motif is characterized by the tetrahedral coordination of a zinc ion by conserved cysteine and histidine residues. We have characterized the prokaryotic Cys2His2 zinc finger motif, included in the DNA binding region (Ros87) of Ros protein from Agrobacterium tumefaciens, demonstrating that, although possessing a similar zinc coordination sphere, this domain presents significant differences from its eukaryotic counterpart. Furthermore, basic residues flanking the zinc binding region on either side have been demonstrated, by Electrophoretic Mobility Shift Assay (EMSA) experiments, to be essential for Ros DNA binding. In spite of this wealth of knowledge, the structural details of the mechanism through which the prokaryotic zinc fingers recognize their target genes are still unclear. Here, to gain insights into the molecular DNA recognition process of prokaryotic zinc finger domains we applied a strategy in which we performed molecular docking studies using a combination of Nuclear Magnetic Resonance (NMR) and Molecular Dynamics (MD) simulations data. The results demonstrate that the MD ensemble provides a reasonable picture of Ros87 backbone dynamics in solution. The Ros87-DNA model indicates that the interaction involves the first two residue of the first ?-helix, and several residues located in the basic regions flanking the zinc finger domain. Interestingly, the prokaryotic zinc finger domain, mainly with the C-terminal tail that is wrapped around the DNA, binds a more extended recognition site than the eukaryotic counterpart. Our analysis demonstrates that the introduction of the protein flexibility in docking studies can improve, in terms of accuracy, the quality of the obtained models and could be particularly useful for protein showing high conformational heterogeneity as well as for computational drug design applications. PMID:25240418

Russo, Luigi; Palmieri, Maddalena; Caso, Jolanda Valentina; D'Abrosca, Gianluca; Diana, Donatella; Malgieri, Gaetano; Baglivo, Ilaria; Isernia, Carla; Pedone, Paolo V; Fattorusso, Roberto

2015-02-16

382

Complete NLO QCD Corrections for Tree Level Delta F = 2 FCNC Processe  

CERN Document Server

Anticipating the important role of tree level FCNC processes in the indirect search for new physics at distance scales as short as 10^-19-10^-21 m, we present complete NLO QCD corrections to tree level Delta F=2 processes mediated by heavy colourless gauge bosons and scalars. Such contributions can be present at the fundamental level when GIM mechanism is absent as in numerous Z' models, gauged flavour models with new heavy neutral gauge bosons and Left-Right symmetric models with heavy neutral scalars. They can also be generated at one loop in models having GIM at the fundamental level and MFV of which Two-Higgs Doublet models with and without SUSY are the best known examples. In models containing vectorial heavy fermions that mix with the standard chiral quarks and models in which Z and SM neutral Higgs H mix with new heavy gauge bosons and scalars also tree-level Z and SM neutral Higgs contributions to Delta F=2 processes are possible. In all these extensions new local operators are generated having Wilson...

Buras, Andrzej J

2012-01-01

383

The disposal of intermediate-level radioactive liquid waste by hydraulic fracturing process  

International Nuclear Information System (INIS)

The hydraulic fracturing process is characterized by combination of the treatment with the disposal of ILLW (intermediate-level liquid waste). It is of cement solidification in deep geology stratum. First of all, it is necessary to select a suitable disposal site with detailed information on geology and hydrogeology. The process has such advantages as simple, low cost, large capacity of disposal, safe and reliable in technology. It is an attractive process of ILLW. Since 1980's, the research and the concept design of the hydraulic fracturing process have been initiated for disposal of ILLW. It is demonstrated by the field tests. The authors considered that the geological structure near Sichuan Nuclear Fuel Plant fits the disposal of ILLW by the hydraulic fracturing process

384

Role of intrinsic molecular dipole in energy level alignment at organic interfaces  

Science.gov (United States)

The energy level alignment in metal-organic and organic-organic junctions of the widely used materials tris-(8-hydroxyquinoline)aluminum (Alq3) and 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA) is investigated. The measured alignment schemes for single and bilayer films of Alq3 and NTCDA are interpreted with the integer charge transfer (ICT) model. Single layer films of Alq3 feature a constant vacuum level shift of ˜0.2-0.4 eV in the absence of charge transfer across the interface. This finding is attributed to the intrinsic dipole of the Alq3 molecule and (partial) ordering of the molecules at the interfaces. The vacuum level shift changes the onset of Fermi level pinning, as it changes the energy needed for equilibrium charge transfer across the interface.

Lindell, Linda; ?ak?r, Deniz; Brocks, Geert; Fahlman, Mats; Braun, Slawomir

2013-06-01

385

Energy level decay and excited state absorption processes in dysprosium-doped fluoride glass  

Science.gov (United States)

The primary excited state decay processes relating to the H613/2?H615/2˜3 ?m laser transition in singly Dy3+-doped fluoride (ZBLAN) glass have been investigated in detail using time-resolved fluorescence spectroscopy. Selective laser excitation of the F69/2, H67/2 energy levels at 1125 nm and F611/2, H69/2 energy levels at 1358 nm established that the energy levels above the H611/2 level, excluding the F49/2 level, are entirely quenched by multiphonon emission in ZBLAN glass. The H611/2 and H613/2 energy levels emit luminescence with peaks at ˜1700 and ˜2880 nm, respectively, but at low quantum (luminescence) efficiencies. The quantum efficiency of the H611/2 level and H613/2 level is ˜9×10-5 and ˜1.3×10-2, respectively, for [Dy3+]=0.5 mol % based on calculations of the radiative lifetimes using the Judd-Ofelt theory. Excited state absorption (ESA) was detected by monitoring the rise time of the 1700 nm luminescence after tuning the probe wavelength across the spectral range from 1100 to 1400 nm. As a result of nonradiative decay of the higher excited states, ESA contributes to the heating of ˜3 ?m fiber lasers based on Dy3+-doped fluoride glass. For [Dy3+] up to 4 mol %, we found no evidence of energy transfer processes between Dy3+ ions that influence the decay characteristics of the H611/2 and H613/2 energy levels.

Gomes, Laércio; Librantz, André Felipe Henriques; Jackson, Stuart D.

2010-03-01

386

Molecular Mechanisms of SERT in Platelets: Regulation of Plasma Serotonin Levels  

OpenAIRE

Long before it received fame as a neurotransmitter, 5-hydroxytryptamine was recognized as a vasoconstrictor in serum and therefore termed “serotonin.” Elevated serotonin levels in the plasma have been linked to hypertension and various cardiovascular diseases. The serotonin transporter (SERT) located in the platelet plasma membrane is the fundamental regulator of plasma serotonin concentration. Intriguingly, the expression of SERT in the platelet membrane is regulated by plasma levels of ...

Mercado, Charles P.; Kilic, Fusun

2010-01-01

387

Processing of meteoritic organic materials as a possible analog of early molecular evolution in planetary environments.  

Science.gov (United States)

The composition of the Sutter's Mill meteorite insoluble organic material was studied both in toto by solid-state NMR spectroscopy of the powders and by gas chromatography-mass spectrometry analyses of compounds released upon their hydrothermal treatment. Results were compared with those obtained for other meteorites of diverse classifications (Murray, GRA 95229, Murchison, Orgueil, and Tagish Lake) and found to be so far unique in regard to the molecular species released. These include, in addition to O-containing aromatic compounds, complex polyether- and ester-containing alkyl molecules of prebiotic appeal and never detected in meteorites before. The Sutter's Mill fragments we analyzed had likely been altered by heat, and the hydrothermal conditions of the experiments realistically mimic early Earth settings, such as near volcanic activity or impact craters. On this basis, the data suggest a far larger availability of meteoritic organic materials for planetary environments than previously assumed and that molecular evolution on the early Earth could have benefited from accretion of carbonaceous meteorites both directly with soluble compounds and, for a more protracted time, through alteration, processing, and release from their insoluble organic materials. PMID:24019471

Pizzarello, Sandra; Davidowski, Stephen K; Holland, Gregory P; Williams, Lynda B

2013-09-24

388

A sulfuric-lactic acid process for efficient purification of fungal chitosan with intact molecular weight.  

Science.gov (United States)

The most recent method of fungal chitosan purification, i.e., two steps of dilute sulfuric acid treatment, pretreatment of cell wall at room temperature for phosphate removal and extraction of chitosan from the phosphate free cell wall at high temperature, significantly reduces the chitosan molecular weight. This study was aimed at improvement of this