WorldWideScience
 
 
1

MOLECULAR-LEVEL PROCESS GOVERNING THE INTERACTION OF CONTAMINANTS WITH IRON AND MANGANESE OXIDES  

Science.gov (United States)

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 stru...

2

Direct molecular-level Monte Carlo simulation of Joule-Thomson processes  

Science.gov (United States)

We present an application of the recently developed constant enthalpy-constant pressure Monte Carlo method [Smith, W. R., and Lísal, M., 2002, Phys. Rev. E, 66, 01114] for the direct simulation of Joule-Thomson expansion processes using a molecular-level system model. For the alternative refrigerant HFC-32 (CH2F2), we perform direct simulations of the isenthalpic integral Joule-Thomson effect (temperature drop) resulting from Joule-Thomson expansion from an initial pressure to the representative final pressure of 1 bar. We consider representative expansions from single-phase states yielding final states in both single-phase and two-phase regions. We also predict the dependence of T(P,h) and of the Joule-Thomson coefficient, ?(P,h), on pressure along several representative isenthalps, as well as points on the Joule-Thomson inversion curve. HFC-32 is modelled using a five-site potential taken from the literature, with parameters derived from ab initio calculations and vapour-liquid equilibrium data. The simulated results show excellent agreement with those calculated from an international standard equation of state.

Lísal, Martin; Smith, William R.; Aim, Karel

3

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

Science.gov (United States)

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.

Shuai, Zhigang; Peng, Qian

2014-04-01

4

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

5

Photodissociation processes in molecular beams  

International Nuclear Information System (INIS)

A description is presented of a study of the photodissociation dynamics of molecules in a molecular beam. Photo-fragmentation translational spectroscopy has been utilized to observe the photodissociation dynamics of ozone. Using a supersonic molecular beam and a 10 nanosecond pulsed laser at lambda = 266 nm, the velocities of the fragment products are measured by the method of time of flight. The resolution of the time of flight spectrum of ozone is sufficiently high that the electronic and vibrational states are clearly resolved and identified. Above the threshold (lambda < 310 nm), the quantum yield for the production of O("1D) has been estimated in the past to be unity for the process O_3 ("1A_1) + h?)lambda < 300 nm) ? O_3("1B_2) ? O_2("1?/sub g/) + O("1D). However a small production of O_2 ("3?/sub g/"-) + O("3P) has been observed in this study. The O_2("1?/sub g/) product yields four vibrational states (v = 0, 1, 2, 3) which yields a vibrational temperature of 2700"0K along with narrow energy distributions of rotational levels. These energy distributions are compared with photodissociation models along with the polarization dependence of the dissociative process which was also measured. 143 references

1979-01-01

6

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 H_2

1991-01-01

7

Molecular cooling via Sisyphus processes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a study of Sisyphus cooling of molecules: The scattering of a single photon removes a substantial amount of the molecular kinetic energy and an optical pumping step allows one 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 temperatures. Considerations of the required experimental parameters, for instance the laser p...

2014-01-01

8

Understanding collective behavior at the molecular level  

Science.gov (United States)

Social amoeba transition from a collection of individual cells into a multicellular spore-complex. During this process, amoebae display several interesting phenomena including intercellular signaling, pattern formation, and cell differentiation. At the heart of these phenomena is the exchange of the signaling molecule cyclic-AMP, which has been extensively studied using a variety of indirect monitoring methods. Here we employ a sensor that uses a compound fluorescent protein whose emission spectrum changes in the presence of bound cyclic AMP to directly monitor, in real time and in vivo, intracellular cAMP concentrations. We use cells expressing this sensor in custom made microfabricated chemostats to study how individual cells communicate via cAMP in the aggregation process in a larger effort to bridge the gap between individual and collective behavior of this system. Specifically, we observe changes in aggregatory behavior and measure cAMP signals in response to time-varying extracellular cAMP functions to build a comprehensive model with readily verifiable predictions with the goal of controlling collective behaviors at the molecular level.

Mestler, Troy; Gregor, Thomas

2010-03-01

9

CONTROL STRATEGIES FOR LEVEL PROCESSES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

10

GRACE Level-1 Processing Status  

Science.gov (United States)

The beginning of the science processing for the GRACE mission, called Level-1 processing, consists of data reformatting, data compression, editing, and precise time tag alignment based on GPS precise orbit determination for the formation of the dual one way range. This task is performed at the Jet Propulsion Laboratory, California Institute of Technology (JPL) GRACE Science Data System team working in cooperation with the Physical Oceanography Data Active Archive Center (PO-DAAC). In this talk an overview will be given of the data flow from raw telemetry (Level-0) to Level-1 data which is used to estimate gravity fields by the Level-2 processing centers at the Center for Space Research, University of Texas at Austin, GeoForschungs Zentrum, Potsdam and JPL. Furthermore, a quality control assessment for the Level-1 data products will be discussed as well as experience gained by processing the GRACE data set. Finally an overview will be given of all science data products to be distributed to the science community and the method of distribution.

Kruizinga, G. L.; Bertiger, W. I.; Case, K. E.; Finch, C. J.; Flechtner, F.; Romans, L. J.; Watkins, M. M.; Wu, S. C.

2003-12-01

11

GRACE Level-1 Data Processing  

Science.gov (United States)

The beginning of the science processing for the GRACE mission, called Level-1 processing, consists of data reformatting, data compression, editing, and precise time tag alignment based on GPS precise orbit determination for the formation of the dual one way range. This task is performed at the Jet Propulsion Laboratory, California Institute of Technology (JPL) GRACE Science Data System team working in cooperation with the Physical Oceanography Data Active Archive Center (PO-DAAC). In this talk an overview will be given of the data flow from raw telemetry (Level-0) to Level-1 data which is used to estimate gravity fields by the Level-2 processing centers at the Center for Space Research, University of Texas at Austin, Geo Forschungs Zentrum, Potsdam and JPL. Furthermore, the quality control assessment for all data products will be discussed as well as experience gained by processing the GRACE data set. Finally an overview will be given of all science data products to be distributed to the science community and the method of distribution.

Kruizinga, G. L.; Bertiger, W. I.; Finch, C. J.; Romans, L. J.; Watkins, M. M.; Wu, S. C.

2002-12-01

12

Effect of molecular weight on polymer processability  

Energy Technology Data Exchange (ETDEWEB)

Differences in rheological behavior due to the polymer molecular weight and molecular weight distribution have been shown with the MPT. SBR polymers having high molecular weight fractions develop higher stress relaxation time values due to the higher degree of polymer entanglements. Tests conducted at increasing temperatures show the diminishing influence of the polymer entanglements upon stress relaxation time. EPDM polymers show stress relaxation time and head pressure behavior which correlates with mill processability. As anticipated, compounded stock of EPDM have broad molecular weight distribution has higher stress relaxation time values than EPDM compounds with narrow molecular weight distribution.

Karg, R.F.

1983-01-01

13

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

14

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 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 applications. (author)

2007-11-01

15

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

1980-01-01

16

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

17

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

1982-01-01

18

Systemic structural modular generalization of the crystallography of bound water applied to study the mechanisms of processes in biosystems at the atomic and molecular level  

Energy Technology Data Exchange (ETDEWEB)

The main reasons of the modern scientific revolution, one of the consequences of which are nanotechnologies and the development of interdisciplinary overall natural science (which can build potentially possible atomic structures and study the mechanisms of the processes occurring in them), are considered. The unifying role of crystallography in the accumulation of interdisciplinary knowledge is demonstrated. This generalization of crystallography requires the introduction of a new concept: a module which reflects the universal condition for stability of all real and potential and equilibrium and nonequilibrium structures of matter (their connectivity). A modular generalization of crystallography covers all forms of solids, including the structure of bound water (a system-forming matrix for the self-organization and morphogenesis of hierarchical biosystems which determines the metric selection of all other structural components of these systems). A dynamic model of the water surface layer, which serves as a matrix in the formation of Langmuir monolayers and plays a key role in the occurrence of life on the Earth, is developed.

Bulienkov, N. A., E-mail: lmm@phyche.ac.ru [Russian Academy of Sciences, Frumkin Institute of Physical Chemistry and Electrochemistry (Russian Federation)

2011-07-15

19

Lecture notes on molecular processes in interstellar clouds  

International Nuclear Information System (INIS)

The main topics of these lecture notes are: molecular formation processes, molecular photodestruction processes, recombination processes, gas phase formation schemes in interstellar clouds, rotational population of H2 in interstellar clouds, energy loss processes, heating mechanisms. (BJ)

1975-01-01

20

Maintenance Rehearsal and Single-Level Processing  

Science.gov (United States)

A description of a series of six experiments dealing with human memory processes. They examined the types of codes generated in maintenance rehearsal and the effects of rehearsal time at various single levels of encoding. Data confirmed earlier findings and led to conclusions regarding repetition, encoding and levels of processing. (AMH)

Rundus, Dewey

1977-01-01

 
 
 
 
21

From supramolecular electrochemistry to molecular-level devices  

International Nuclear Information System (INIS)

Supramolecular (multi-component) systems can perform complex functions which result from the cooperation of actions performed by suitably selected molecular components. Looking at supramolecular systems, from the viewpoint of the functions, shows that the concept of macroscopic device can be extended to molecular level. Nature exploits very complex molecular-level devices to substain life, and, in the last twenty years, the development of supramolecular chemistry has allowed the construction of simple molecular-level devices, that are of interest not only for basic research, but also for the growth of nanoscience and nanotechnology. Molecular-level devices operate via electronic and/or nuclear rearrangements, and like macroscopic devices, they need energy to operate and signals to communicate with the operator. Electrochemistry can provide the answer to this dual requirement, since electrons/holes, besides supplying the energy needed to make a devices work, can also be useful to 'read' the state of the system and thus to control and monitor the operation of the device. In this article, some examples of molecular-level devices investigated in our laboratory will be reviewed

2004-09-15

22

Practical ?-Ray Level for Low Molecular Weight Chitosan  

International Nuclear Information System (INIS)

The present work proposes a practical level of ?-Ray to lower the molecular weigh of chitosan irradiated in solid state and water. The molecular weight reduction is up to 80% at ?-ray amount of 50 kGy. The same level of reduction can be achieved by only 20 kGy in the presence of initiator (K2S2O8 or H2O2). The structure is significantly changed in the case of chitosan-acetic acid solution or chitosan dispersed in water with 2% aq. K2S2O8 solution

2003-06-19

23

Molecular assembly of fullerene-conjugated phthalocyanine derivative on Au(111) at single molecular level.  

Science.gov (United States)

Molecular adlayers of doubly C(60)-conjugated phthalocyanine derivatives ((C(60))(2)NiPc) were examined on bare and zinc(II) octaethylporphyrin (ZnOEP)- and coronene-modified Au(111) surfaces. Electrochemical scanning tunneling microscopy (EC-STM) has revealed the structure of the (C(60))(2)NiPc adlayer at single molecular level. The (C(60))(2)NiPc adlayer is strongly influenced by the underlying organic layers, i.e., a disordered, a packed structure of (C(60))(2)NiPc was found on a clean Au(111) surface because of the strong interaction between (C(60))(2)NiPc molecule and Au(111) substrate, whereas a single (C(60))(2)NiPc molecule was clearly distinguished both on ZnOEP and coronene adlayers at a low coverage of (C(60))(2)NiPc molecules. The obtained results in the present study suggest that the underlying organic adlayers play an important role in the formation process of the (C(60))(2)NiPc molecule adlayer. PMID:22173091

Yoshimoto, Soichiro; Masuda, Satoshi; Fukuda, Takamitsu; Kobayashi, Nagao

2012-03-01

24

Wafer level 3-D ICs process technology  

CERN Document Server

This book focuses on foundry-based process technology that enables the fabrication of 3-D ICs. The core of the book discusses the technology platform for pre-packaging wafer lever 3-D ICs. However, this book does not include a detailed discussion of 3-D ICs design and 3-D packaging. This is an edited book based on chapters contributed by various experts in the field of wafer-level 3-D ICs process technology. They are from academia, research labs and industry.

Tan, Chuan Seng; Reif, L Rafael

2009-01-01

25

Gas phase atomic and molecular processes  

Science.gov (United States)

We perform fully quantum mechanical calculations of the lithium 2 p -2 s and sodium 3 p -3 s resonance lines pressure broadened by collisions with helium atoms. Using carefully constructed potential energy surfaces and transition dipole moments, we have obtained the emission and absorption coefficients at temperatures from 200 to 3000 K at wavelengths between 500 and 1000 nm for lithium and at temperatures from 158 to 3000 K at wavelengths between 500 and 760 nm for sodium. Contributions from quasi-bound levels are included. Our results are in good agreement with experiment. These broadened line profiles are important in developing effective diagnostics on the temperatures, densities, albedos and composition of the atmospheres of brown dwarfs and extrasolar giant planets. We compute the diffusion coefficients of ground and excited-state lithium and sodium atoms in a helium gas. They are valuable in predicting the sign and magnitude of the light-induced drift for the gas mixture. We calculate the dispersion coefficients of the long range interactions of alkali-metal atoms with molecular hydrogen and helium atoms. The uncertainties in our results are less than 2%. We study the relaxation of the v = 1 vibrational level of carbon monoxide induced by collisions with helium three atoms in ultracold temperatures. We confirm the Wigner's threshold law which states that in the zero temperature limit the inelastic quenching cross sections are inversely proportional to the velocity of the incident atom. Our calculations agree well with experiment and we find enhanced rate coefficients as compared to those for 4 He-CO. We study the chemistry of hydrogen fluoride in the interstellar medium. We consider fine-structure collisions and find that most fluorine atoms reside in the ground 2 P 3/ 2 state. We calculate the rate coefficients for the reaction of F( 2 P 3/2 ) atoms in collisions with H 2 . Our results agree well with experiment. We confirm the conclusions of Neufeld et al. that in interstellar clouds HF is the major form of gas phase fluorine.

Zhu, Cheng

26

Processing EOS MLS Level-2 Data  

Science.gov (United States)

A computer program performs level-2 processing of thermal-microwave-radiance data from observations of the limb of the Earth by the Earth Observing System (EOS) Microwave Limb Sounder (MLS). The purpose of the processing is to estimate the composition and temperature of the atmosphere versus altitude from .8 to .90 km. "Level-2" as used here is a specialists f term signifying both vertical profiles of geophysical parameters along the measurement track of the instrument and processing performed by this or other software to generate such profiles. Designed to be flexible, the program is controlled via a configuration file that defines all aspects of processing, including contents of state and measurement vectors, configurations of forward models, measurement and calibration data to be read, and the manner of inverting the models to obtain the desired estimates. The program can operate in a parallel form in which one instance of the program acts a master, coordinating the work of multiple slave instances on a cluster of computers, each slave operating on a portion of the data. Optionally, the configuration file can be made to instruct the software to produce files of simulated radiances based on state vectors formed from sets of geophysical data-product files taken as input.

Snyder, W. Van; Wu, Dong; Read, William; Jiang, Jonathan; Wagner, Paul; Livesey, Nathaniel; Schwartz, Michael; Filipiak, Mark; Pumphrey, Hugh; Shippony, Zvi

2006-01-01

27

A Process Calculus for Molecular Interaction Maps  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present the MIM calculus, a modeling formalism with a strong biological basis, which provides biologically-meaningful operators for representing the interaction capabilities of molecular species. The operators of the calculus are inspired by the reaction symbols used in Molecular Interaction Maps (MIMs), a diagrammatic notation used by biologists. Models of the calculus can be easily derived from MIM diagrams, for which an unambiguous and executable interpretation is thus...

Barbuti, Roberto; Maggiolo-schettini, Andrea; Milazzo, Paolo; Pardini, Giovanni; Rama, Aureliano

2009-01-01

28

A Process Calculus for Molecular Interaction Maps  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present the MIM calculus, a modeling formalism with a strong biological basis, which provides biologically-meaningful operators for representing the interaction capabilities of molecular species. The operators of the calculus are inspired by the reaction symbols used in Molecular Interaction Maps (MIMs), a diagrammatic notation used by biologists. Models of the calculus can be easily derived from MIM diagrams, for which an unambiguous and executable interpretation is thus obtained. We give...

Roberto Barbuti; Andrea Maggiolo-Schettini; Paolo Milazzo; Giovanni Pardini; Aureliano Rama

2009-01-01

29

Alternative low-level waste processing techniques  

International Nuclear Information System (INIS)

This paper presents some new and innovative ways to use commercially available process shields to reduce utility low-level radioactive waste processing costs. With the current market demanding more and more dewatering and in-container solidification, it has become necessary to look for way to offset contractor demurrage and detention charges on casks. Through the use of inexpensive on-site storage containers (OSSCs) with specially designed lids, the cost for processing is significantly reduced. These OSSCs, with secondary ports, allow for in-container dewatering or solidification, thereby amply offsetting cask demurrage charges assessed by mobile service contractors. Several versions of these OSSCs are available to the industry. They range in capacity from 7.35 to 3000 ft "3 and each can be tailored to meet a customer's specific on-site requirements, as well as the requisite compatibility with currently licensed transport containers. Each can be equipped with special lids to accommodate various types of both in-plant and mobil processing systems. The design basis of these processing containers is based on a concrete structure with heavy steel reinforcement

1986-11-16

30

Renewal processes and fluctuation analysis of molecular motor stepping  

CERN Document Server

We model the dynamics of a processive or rotary molecular motor using a renewal processes, in line with the work initiated by Svoboda, Mitra and Block. We apply a functional technique to compute different types of multiple-time correlation functions of the renewal process, which have applications to bead-assay experiments performed both with processive molecular motors, such as myosin V and kinesin, and rotary motors, such as F1-ATPase.

Santos, J E; Parmeggiani, A; Frey, E; Santos, Jaime E.; Franosch, Thomas; Parmeggiani, Andrea; Frey, Erwin

2005-01-01

31

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...

32

Separating Mechanical and Chemical Contributions to Molecular-Level Friction  

Energy Technology Data Exchange (ETDEWEB)

The authors use force-probe microscopy to study the friction force and the adhesive interaction for molecular monolayer self-assembled on both Au probe tips and substrate surfaces. By systematically varying the chemical nature of the end groups on these monolayers the authors have, for the first time, delineated the mechanical and chemical origins of molecular-level friction. They use chemically inert {double_bond}CH{sub 3} groups on both interracial surfaces to establish the purely mechanical component of the friction and contrast the results with the findings for chemically active {double_bond}COOH end-groups. In addition, by using odd or even numbers of methylene groups in the alkyl backbones of the molecules they are able to determine the levels of inter-film and intra-film hydrogen bonding.

KIM,HYUN I.; HOUSTON,JACK E.

2000-08-14

33

Molecular simulation of non-equilibrium methane hydrate decomposition process  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: Highlights: > Decomposition of methane hydrate is studied with molecular dynamics simulations. > Simulations are performed under adiabatic conditions (no thermostats). > The effects of heat and mass transfer during the decomposition are observed. > Temperature gradients are established as the hydrate decomposes. > Intrinsic reaction kinetics picture of hydrate dissociation is revisited. - Abstract: We recently performed constant energy molecular dynamics simulations of the endothermic decomposition of methane hydrate in contact with water to study phenomenologically the role of mass and heat transfer in the decomposition rate [S. Alavi, J.A. Ripmeester, J. Chem. Phys. 132 (2010) 144703]. We observed that with the progress of the decomposition front temperature gradients are established between the remaining solid hydrate and the solution phases. In this work, we provide further quantitative macroscopic and molecular level analysis of the methane hydrate decomposition process with an emphasis on elucidating microscopic details and how they affect the predicted rate of methane hydrate decomposition in natural methane hydrate reservoirs. A quantitative criterion is used to characterize the decomposition of the hydrate phase at different times. Hydrate dissociation occurs in a stepwise fashion with rows of sI cages parallel to the interface decomposing simultaneously. The correlations between decomposition times of subsequent layers of the hydrate phase are discussed.

Bagherzadeh, S.Alireza; Englezos, Peter [Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia, V6T 1Z3 (Canada); Alavi, Saman, E-mail: saman.alavi@nrc-cnrc.gc.ca [Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Dr., Ottawa, Ontario, K1A 0R6 (Canada); Ripmeester, John A., E-mail: john.ripmeester@nrc-cnrc.gc.ca [Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Dr., Ottawa, Ontario, K1A 0R6 (Canada)

2012-01-15

34

A Process Calculus for Molecular Interaction Maps  

CERN Document Server

We present the MIM calculus, a modeling formalism with a strong biological basis, which provides biologically-meaningful operators for representing the interaction capabilities of molecular species. The operators of the calculus are inspired by the reaction symbols used in Molecular Interaction Maps (MIMs), a diagrammatic notation used by biologists. Models of the calculus can be easily derived from MIM diagrams, for which an unambiguous and executable interpretation is thus obtained. We give a formal definition of the syntax and semantics of the MIM calculus, and we study properties of the formalism. A case study is also presented to show the use of the calculus for modeling biomolecular networks.

Barbuti, Roberto; Milazzo, Paolo; Pardini, Giovanni; Rama, Aureliano; 10.4204/EPTCS.11.3

2009-01-01

35

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.

Taylor, Jeremy Philip

2001-01-01

36

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

1975-10-06

37

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

38

The beauty of knots at the molecular level.  

Science.gov (United States)

What makes a given object look beautiful to the observer, be it in the macroscopic world or at the molecular level? This very general question will be briefly addressed at the beginning of this essay, in relation to contemporary molecular chemistry and biology, leading to the general statement that, most of the time, beauty is tightly connected to function as well as to the cultural background of the observer. The main topic of the present article will be that of topologically non-trivial molecules or molecular ensembles and the fascination that such species have exerted on molecular or solid state chemists. Molecules with a graph identical to Kuratowski's K? or K?,? graphs are indeed highly attractive from an aesthetical viewpoint, but perhaps even more fascinating and beautiful are molecular knots. A general discussion will be devoted to these compounds, which are still considered as exotic species because of the very limited number of efficient synthetic strategies leading to their preparation. Particularly efficient are templated approaches based either on transition metals such as copper(I) or on organic groups able to form hydrogen bonds or acceptor-donor stacks. A particularly noteworthy property of knots, and in particular of the trefoil knot, is their topological chirality. The isolation of both enantiomers of the trefoil knot (3?) could be achieved and showed that such species have fascinating chiroptical properties. Finally, various routes to more complex and beautiful knots than the trefoil knot, which is the simplest non-trivial knot, will be discussed in line with the remarkable ability of transition metals to gather and orient in a very precise fashion several organic components in their coordination spheres, thus leading to synthetic precursors displaying geometries which are perfectly well adapted to the preparation of the desired knots or links. PMID:22025072

Sauvage, Jean-Pierre; Amabilino, David B

2012-01-01

39

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

1991-10-23

40

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

 
 
 
 
41

The SILMO laser uranium enrichment molecular process  

International Nuclear Information System (INIS)

Laser uranium enrichment is based on the different light absorption characteristics of the two uranium hexafluoride (U F6) molecules. The process principles are detailed and its application to plant-scale uranium enrichment with low temperature, high flow rate and scavenger issues is discussed. Infrared technology is now largely imposed for this process, enabling higher photodissociation performances. Laser issues are still under study

1996-03-20

42

Rovibronic energy levels for triplet electronic states of molecular deuterium  

CERN Document Server

Optimal set of 1046 rovibronic energy levels for 35 triplet electronic states of $D_2$ has been obtained by means of statistical analysis of all available values of wavenumbers of rovibronic transitions studied in emission, absorption, laser and anticrossing spectroscopic experiments of various authors. We used new method of the analysis (Lavrov, Ryazanov, JETPLett., 2005), which does not need any a priory assumptions concerning molecular structure being based only on two fundamental principles: maximum likelihood and Rydberg-Ritz. The method provides the opportunity to obtain the estimation of experimental errors of the wavenumbers independent from those reported in original papers. From 3801 published wavenumber values 207 were excluded as blunders, wavenumber values of 122 from them were measured in our experiments. The remaining set of 3716 experimental data has been divided into 14 subsets of uniformly precise data having close to normal error distribution. Unknown shift between levels of ortho- and para...

Lavrov, B P

2007-01-01

43

Optical probes of atomic and molecular decay processes.  

Energy Technology Data Exchange (ETDEWEB)

The study of molecular photoionization and photodissociation dynamics provides insight into the intramolecular mechanisms by which energy and angular momentum are exchanged and redistributed among the internal degrees of freedom of highly excited molecules and, more specifically, into the mechanisms that determine the decay pathways and resulting product-state distributions for the excited molecules. These mechanisms lie at the heart of one of the principal subjects of chemistry, that is, understanding and controlling the factors that govern the making and breaking of chemical bonds. The objective of this experimental research program is to elucidate these fundamental mechanisms and to provide useful prototypes for the development of a general qualitative understanding of their ramifications. In this program, the primary focus is on resonant processes in the ionization and dissociation continua, that is, on autoionization and predissociation. These processes are studied as a function of the electronic, vibrational, and rotational quantum numbers of the resonances, allowing a better understanding of their fundamental mechanisms. In the past three years, the primary emphasis of this experimental program has been on understanding the process of vibrational autoionization in Rydberg states of small polyatomic molecules. Vibrational autoionization corresponds to the decay of resonances above the ionization threshold into the continuum through the conversion of vibrational energy into electronic/translational energy of the highly excited/ejected electron. In polyatomic molecules, I am particularly interested in determining how this process depends on both the specific normal vibrational modes involved in the process and the electronic character of the resonances. In this program, the experimental approach relies on laser-based, double-resonance techniques to prepare the selected excited states in the molecules of interest, and on a variety of detection techniques to characterize both the photoexcitation and subsequent decay processes. These techniques include mass spectrometry, dispersive and threshold photoelectron spectroscopy, laser-induced fluorescence, fluorescence-dip spectroscopy, and laser-induced grating spectroscopy. While the instrumentation is currently available for each of these techniques, two instruments deserve special mention. First, a high-resolution magnetic-bottle electron spectrometer has been developed that is equipped with a pulsed, skimmed molecular beam source. This instrument is capable of {approx}3-4 meV resolution in the electron kinetic energy while providing a collection efficiency of {approx}50%. Second, a time-of-flight mass spectrometer has been constructed with a similar molecular beam source. This instrument is currently being adapted to allow both ion- and electron-imaging studies. A typical experimental study is performed in three steps. First, resonant one-color multiphoton ionization is used to map out the transition between the ground state of the molecule of interest and the low-lying excited state to be used as an intermediate in the double-resonance process. The lasers used in these studies are Nd:YAG-pumped dye lasers with {approx}5 ns pulse durations. In general, this pump transition corresponds to a one- or two-photon process, and the laser output is frequency doubled, tripled, or mixed to generate light in the region of interest. In molecules such as ammonia and aniline, the pump transitions of interest are well characterized, allowing the unambiguous choice of pump transitions that access levels with the rovibronic character of interest. In other cases, the spectroscopy of the pump transition must be analyzed before it can be useful for the double-resonance experiments. In the second step, the pump laser is fixed on the pump transition of interest and a second laser is used to probe transitions from the upper state of the pump transition to the autoionizing or predissociating resonances in the region of interest. The double-resonance spectrum is recorded by scanning the second l

Pratt, S. T. (Chemistry)

2008-01-01

44

Computational approaches to shed light on molecular mechanisms in biological processes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Computational approaches based on Molecular Dynamics simulations, Quantum Mechanical methods and 3D Quantitative Structure-Activity Relationships were employed by computational chemistry groups at the University of Milano-Bicocca to study biological processes at the molecular level. The paper reports the methodologies adopted and the results obtained on Aryl hydrocarbon Receptor and homologous PAS proteins mechanisms, the properties of prion protein peptides, the reaction pathway of hydrogena...

Moro, Giorgio; Bonati, Laura; Bruschi, Maurizio; Cosentino, Ugo; Gioia, Luca; Fantucci, Pier Carlo; Pandini, Alessandro; Papaleo, Elena; Pitea, Demetrio; Saracino, Gloria A. A.; Zampella, Giuseppe

2007-01-01

45

Computational approaches to shed light on molecular mechanisms in biological processes  

Science.gov (United States)

Computational approaches based on Molecular Dynamics simulations, Quantum Mechanical methods and 3D Quantitative Structure-Activity Relationships were employed by computational chemistry groups at the University of Milano-Bicocca to study biological processes at the molecular level. The paper reports the methodologies adopted and the results obtained on Aryl hydrocarbon Receptor and homologous PAS proteins mechanisms, the properties of prion protein peptides, the reaction pathway of hydrogenase and peroxidase enzymes and the defibrillogenic activity of tetracyclines.

Bonati, Laura; Bruschi, Maurizio; Cosentino, Ugo; De Gioia, Luca; Fantucci, Pier Carlo; Pandini, Alessandro; Papaleo, Elena; Pitea, Demetrio; Saracino, Gloria A.A.; Zampella, Giuseppe

2011-01-01

46

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

47

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

48

Molecular beam overrun in sampling transient combustion processes  

International Nuclear Information System (INIS)

Effects of combustion-generated source temperature variations on direct sampling in a molecular beam mass spectrometer are examined. The problem of particular concern is the influence of beam overrun on the distribution of molecules arriving at the detector. The overrun is due to the fact that the hotter, and thus faster, constituents of the molecular beam are formed later than its colder, and thus slower, portions. Photolysis of NO2 in Ar and flash-ignited mixtures of Ar/CH4/O2/NO2 using a chopped molecular beam time-of-flight technique yields time-resolved temperature measurements, while concomitant numerical analysis predicts quite accurately the observed beam overrun. Analysis of continuous sampling in representative transient combustion processes indicates that the molecular beam mass spectrometer is capable of measuring meaningful time-resolved concentration profiles

1984-09-27

49

Solidification process for high level radioactive waste  

International Nuclear Information System (INIS)

Purpose: To integrally solidify high level radioactive wastes with water-curable solidifying material thereby improve the heat- and radiation-resistance. Constitution: High level radioactive wastes are integrally solidified with water curable solidifying material comprising a mixture of alumina cements, aggregates, inorganic fluidizing materials and dispersing agent. Alumina cements are mainly composed of calcium aluminate and excellent in refractory property. Chamotte particles and baked bauxite particles are used as the aggregates, which can improve the strength of the solidification products. Fine alumina powder and fine silica powder of less than 10 ?m radius are used as the inorganic fluidizing materials and condensated phosphoric acid salt and polycarboxylic acid type polymeric surface active agent are used as the dispersing agents for improving the slidability between the particles. (Yoshino, Y.)

1986-11-10

50

Processing method of high level radioactive solution  

International Nuclear Information System (INIS)

A reagent which acts on zirconium to form precipitates is added to zirconium contained in a solution of spent nuclear fuels or a high level radioactive solution generated along with reprocessing. As the reagent, phosphoric acid, molybdic acid, telluric acid or salts thereof, namely, phosphate, molybdate and tellurate can be used. In addition, if the addition of these reagents and heat treatment are joined, formation of precipitates can be promoted. According to this method, zirconium present in the high level radioactive solution in the form of fine precipitates, colloid or in a dissolved state can be converted to easily removable precipitates without losing safety or applying significant effects on co-existent elements. (T.M.)

1996-08-27

51

Processing method of high level radioactive solution  

Energy Technology Data Exchange (ETDEWEB)

A reagent which acts on zirconium to form precipitates is added to zirconium contained in a solution of spent nuclear fuels or a high level radioactive solution generated along with reprocessing. As the reagent, phosphoric acid, molybdic acid, telluric acid or salts thereof, namely, phosphate, molybdate and tellurate can be used. In addition, if the addition of these reagents and heat treatment are joined, formation of precipitates can be promoted. According to this method, zirconium present in the high level radioactive solution in the form of fine precipitates, colloid or in a dissolved state can be converted to easily removable precipitates without losing safety or applying significant effects on co-existent elements. (T.M.)

Kubota, Masumitsu; Morita, Yasuji; Yamaguchi, Isoo; Fujiwara, Takeshi

1998-03-10

52

Molecular-beam studies of primary photochemical processes  

International Nuclear Information System (INIS)

Application of the method of molecular-beam photofragmentation translational spectroscopy to the investigation of primary photochemical processes of polyatomic molecules is described. Examples will be given to illustrate how information concerning the energetics, dynamics, and mechanism of dissociation processes can be obtained from the precise measurements of angular and velocity distributions of products in an experiment in which a well-defined beam of molecules is crossed with a laser

1983-01-10

53

High-level waste processing and disposal  

International Nuclear Information System (INIS)

Without reprocessing, spent LWR fuel itself is generally considered an acceptable waste form. With reprocessing, borosilicate glass canisters, have now gained general acceptance for waste immobilization. The current first choice for disposal is emplacement in an engineered structure in a mined cavern at a depth of 500-1000 meters. A variety of rock types are being investigated including basalt, clay, granite, salt, shale, and volcanic tuff. This paper gives specific coverage to the national high level waste disposal plans for France, the Federal Republic of Germany, Japan and the United States. The French nuclear program assumes prompt reprocessing of its spent fuels, and France has already constructed the AVM. Two larger borosilicate glass plants are planned for a new French reprocessing plant at La Hague. France plans to hold the glass canisters in near-surface storage for a forty to sixty year cooling period and then to place them into a mined repository. The FRG and Japan also plan reprocessing for their LWR fuels. Both are currently having some fuel reprocessed by France, but both are also planning reprocessing plants which will include waste vitrification facilities. West Germany is now constructing the PAMELA Plant at Mol, Belgium to vitrify high level reprocessing wastes at the shutdown Eurochemic Plant. Japan is now operating a vitrification mockup test facility and plans a pilot plant facility at the Tokai reprocessing plant by 1990. Both countries have active geologic repository programs. The United State program assumes little LWR fuel reprocessing and is thus primarily aimed at direct disposal of spent fuel into mined repositories. However, the US have two borosilicate glass plants under construction to vitrify existing reprocessing wastes

1984-11-11

54

Selective vibrational pumping of a molecular beam by a stimulated Raman process  

International Nuclear Information System (INIS)

Stimulated Raman process is used to selectively pump a highly excited vibrational state in a molecular beam. Theoretical evaluation shows that continuous lasers with power of less than 1 W can efficiently pump a single rotational-vibrational level of many simple molecules. Characteristics of the selectively pumped molecular beam and operational conditions are discussed theoretically. The experiment on a Na2 beam is found to agree with theoretical predictions. A flux of 4 x 10 to the 7th/s in the v = 31, J = 5 excited level has been obtained with use of two CW dye lasers with powers of 80 and 300 mW. 33 references

1985-01-01

55

Selective vibrational pumping of a molecular beam by a stimulated Raman process  

Energy Technology Data Exchange (ETDEWEB)

Stimulated Raman process is used to selectively pump a highly excited vibrational state in a molecular beam. Theoretical evaluation shows that continuous lasers with power of less than 1 W can efficiently pump a single rotational-vibrational level of many simple molecules. Characteristics of the selectively pumped molecular beam and operational conditions are discussed theoretically. The experiment on a Na2 beam is found to agree with theoretical predictions. A flux of 4 x 10 to the 7th/s in the v = 31, J = 5 excited level has been obtained with use of two CW dye lasers with powers of 80 and 300 mW. 33 references.

Shimizu, F.; Shimizu, K.; Takuma, H.

1985-05-01

56

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

57

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.

2009-01-01

58

Manipulating the conduction process of a molecular resonant tunneling diode  

International Nuclear Information System (INIS)

In this work we propose two methods to manipulate the conduction process in a molecular resonant tunneling diode. In the first proposal we make use of the fact that by twisting the molecule along the long axis, we can generate a nonlinear coupling between the conduction electrons and the phonons. In the second proposal, we allow a light of appropriate frequency to pump the electrons from the ground state to the first excited state. This mechanism generates an additional current across the molecular resonant tunneling diode. (author)

2006-01-01

59

Observing phthalate leaching from plasticized polymer films at the molecular level.  

Science.gov (United States)

Phthalates, the most widely used plasticizers in poly(vinyl chloride) (PVC), have been extensively studied. In this paper, a highly sensitive, easy, and effective method was developed to examine short-term phthalate leaching from PVC/phthalate films at the molecular level using sum frequency generation vibrational spectroscopy (SFG). Combining SFG and Fourier transform infrared spectroscopy (FTIR), surface and bulk molecular structures of PVC/phthalate films were also comprehensively evaluated during the phthalate leaching process under various environments. The leaching processes of two phthalates, diethyl phthalate (DEP) and dibutyl phthalate (DBP), from the PVC/phthalate films with various weight ratios were studied. Oxygen plasma was applied to treat the PVC/phthalate film surfaces to verify its efficacy on preventing/reducing phthalate leaching from PVC. Our results show that DBP is more stable than DEP in PVC/phthalate films. Even so, DBP molecules were still found to very slowly leach to the environment from PVC at 30 °C, at a rate much slower than DEP. Also, the bulk DBP content substantially influences the DBP leaching. Higher DBP bulk concentration yields less stable DBP molecules in the PVC matrix, allowing molecules to leach from the polymer film more easily. Additionally, DBP leaching is very sensitive to temperature changes; higher temperature can strongly enhance the leaching process. For most cases, the oxygen plasma treatment can effectively prevent phthalate leaching from PVC films (e.g., for samples with low bulk concentrations of DBP-5 and 30 wt %). It is also capable of reducing phthalate leaching from high DBP bulk concentration PVC samples (e.g., 70 wt % DBP in PVC/DBP mixture). This research develops a highly sensitive method to detect chemicals at the molecular level as well as provides surface and bulk molecular structural changes. The method developed here is general and can be applied to detect small amounts of chemical/biological environmental contaminants. PMID:24725143

Zhang, Xiaoxian; Chen, Zhan

2014-05-01

60

Mesoscopic Properties of Molecular Folding and Aggregation Processes  

Science.gov (United States)

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 between conformational (pseudo)phases is, however, that these transitions are typically rather smooth processes, i.e., thermodynamic activity is not necessarily signalized by strong entropic or energetic fluctuations. Nonetheless, in order to understand generic properties of molecular structure-formation processes, the analysis of mesoscopic models from a statistical physics point of view enables first insights into the nature of conformational transitions in small systems. Here, we review recent results obtained by means of sophisticated generalized-ensemble computer simulations of minimalistic coarse-grained models.

Bachmann, Michael; Janke, Wolfhard

2008-11-01

 
 
 
 
61

Cisplatin and platinum drugs at the molecular level. (Review).  

Science.gov (United States)

Over twenty years of intensive work toward improvement of cisplatin, and with hundreds of platinum drugs tested, has resulted in the introduction of the widely used carboplatin and of oxaliplatin used only for a very narrow spectrum of cancers. A number of interesting platinum compounds including the orally administered platinum drug JM216, nedaplatin, the sterically hindered platinum(II) complex ZD0473, the trinuclear platinum complex BBR3464, and the liposomal forms Lipoplatin and SPI-77 are under clinical evaluation. This review summarizes the molecular mechanisms of platinum compounds for DNA damage, DNA repair and induction of apoptosis via activation or modulation of signaling pathways and explores the basis of platinum resistance. Cisplatin, carboplatin, oxaliplatin and most other platinum compounds induce damage to tumors via induction of apoptosis; this is mediated by activation of signal transduction leading to the death receptor mechanisms as well as mitochondrial pathways. Apoptosis is responsible for the characteristic nephrotoxicity, ototoxicity and most other toxicities of the drugs. The major limitation in the clinical applications of cisplatin has been the development of cisplatin resistance by tumors. Mechanisms explaining cisplatin resistance include the reduction in cisplatin accumulation inside cancer cells because of barriers across the cell membrane, the faster repair of cisplatin adducts, the modulation of apoptotic pathways in various cells, the upregulation in transcription factors, the loss of p53 and other protein functions and a higher concentration of glutathione and metallothioneins in some type of tumors. A number of experimental strategies to overcome cisplatin resistance are at the preclinical or clinical level such as introduction of the bax gene, inhibition of the JNK pathway, introduction of a functional p53 gene, treatment of tumors with aldose reductase inhibitors and others. Particularly important are combinations of platinum drug treatments with other drugs, radiation and the emerging gene therapy regimens. PMID:14534679

Boulikas, Teni; Vougiouka, Maria

2003-01-01

62

Advances Towards Synthetic Machines at the Molecular and Nanoscale Level  

Directory of Open Access Journals (Sweden)

Full Text Available The fabrication of increasingly smaller machines to the nanometer scale can be achieved by either a “top-down” or “bottom-up” approach. While the former is reaching its limits of resolution, the latter is showing promise for the assembly of molecular components, in a comparable approach to natural systems, to produce functioning ensembles in a controlled and predetermined manner. In this review we focus on recent progress in molecular systems that act as molecular machine prototypes such as switches, motors, vehicles and logic operators.

Kristina Konstas

2010-06-01

63

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

64

Training molecularly enabled field biologists to understand organism-level gene function.  

Science.gov (United States)

A gene's influence on an organism's Darwinian fitness ultimately determines whether it will be lost, maintained or modified by natural selection, yet biologists have few gene expression systems in which to measure whole-organism gene function. In the Department of Molecular Ecology at the Max Planck Institute for Chemical Ecology we are training "molecularly enabled field biologists" to use transformed plants silenced in the expression of environmentally regulated genes and the plant's native habitats as "laboratories." Research done in these natural laboratories will, we hope, increase our understanding of the function of genes at the level of the organism. Examples of the role of threonine deaminase and RNA-directed RNA polymerases illustrate the process. PMID:18511883

Kang, Jin-Ho; Baldwin, Ian T

2008-07-31

65

Amino-nitro-azobenzene dimers as a prototype for a molecular-level machine  

International Nuclear Information System (INIS)

Low-temperature scanning tunnelling microscope measurements of an X-shaped dimer, consisting of two amino-nitro-azobenzene molecules, on a Au(111)-surface are presented. Electron-induced manipulation switches either the upper- or the lower-lying molecule. These reversible switching processes are based on the cis-trans isomerization of the azobenzene molecules. The switching of the upper molecule moves the lower-lying molecule in a controlled way. Thus mechanical work is performed. This proof-of-principle shows the ability of azobenzene molecules to act as a molecular-level machine

2007-12-12

66

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

67

Mesoscopic Properties of Molecular Folding and Aggregation Processes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

68

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.

2012-01-01

69

Fabrication process of molecular memory circuits by nanoimprint lithography  

Science.gov (United States)

We have utilized the nanoimprint lithography process described this paper to fabricate a rewritable, nonvolatile memory cell with an equivalent density of 6.4 Gbits/cm2. The architecture of the circuit was based on an 8x8 crossbar structure with an active molecular layer sandwiched between the top and bottom electrodes. A liftoff process was utilized to produce the top and bottom electrodes, made of Pt/Ti bilayers. The active molecular layer was deposited by the Languir-Blodgett technique. We proposed the use of a new class of nanoimprint resist formulated by dissolving a polymer in its monomer, such as poly(benzyl methacrylate) dissolved in benzyl methacrylate (~8%/92% wt). The new resist enabled us to achieve Pt /Ti lines of 40 nm in width and 130 nm in pitch, as described in this paper. Our overall nanofabrication process has the advantages of relatively low temperature (~70°C) and pressure (~500 psi or 4.5 MPa), both of which are critical to preserving the integrity of the molecular layer.

Jung, Gun-Young; Ganapathiappan, S.; Li, Xuema; Ohlberg, Dougleas A. A.; Olynick, Deidre L.; Chen, Yong; Wu, Wei; Wang, Shih-Yuan; Tong, William M.; Williams, R. S.

2004-05-01

70

Molecular and dust scattering processes in astrophysical environments  

Science.gov (United States)

Understanding the formation and evolution of structure in the universe requires knowledge of the stellar energy output and its processing by gas and dust, evaluating the abundances of atomic and molecular species, and constraining thermodynamic parameters. Molecules, with molecular hydrogen and carbon monoxide being the most abundant, are a major component of the interstellar medium, and play an essential role in structure formation, by participating in gas cooling. Molecular fluorescence studies aim to provide a better interpretation of far-ultraviolet observations, constraining the molecular abundances and their interaction with the radiation field. The fluorescent emission lines offer a set of diagnostics for molecules complementary to absorption line spectroscopy and to observations at infrared and radio wavelengths, but are often poorly reproduced by models. In this work, I have developed and expanded fluorescence models for molecular hydrogen and carbon monoxide, and employed them in determining the spatial distribution of CO in cometary comae, in characterizing the effects of partial frequency redistribution for emission line scattering in planetary atmospheres and reflection nebulae, and in abundance determinations from Bowen fluorescence lines of H 2 in planetary nebulae. Follow-up optical and infrared observations were used in addition to UV data to diagnose molecular excitation, temperature, and spatial distribution in planetary nebula M27. Knowledge of the spectral energy distribution of the exciting stars in the far- ultraviolet is essential in constraining both the fluorescence models and understanding the scattering properties of nebular gas and dust. Sounding rocket observations of the Trifid and Orion nebulae, performed as part of this work, provided the necessary dynamic range and spatial resolution to measure simultaneously the nebular scattered light and the spectral energy distribution of the illuminating stars. These low extinction sight lines offered a unique view of the intrinsic stellar output below 1200 Å, and an excellent proving ground for the instrument performance. The analysis of these observations using fluorescence and dust scattering models is underway.

Lupu, Roxana-Elena

2009-06-01

71

Fermi level alignment in molecular nanojunctions and its relation to charge transfer  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The alignment of the Fermi level of a metal electrode within the gap of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of a molecule is a key quantity in molecular electronics, which can vary the electron transparency of a single-molecule junction by orders of magnitude. We present a quantitative analysis of the relation between this level alignment (which can be estimated from charging free molecules) and charge transfer for bipyridine and bi...

Stadler, Robert; Jacobsen, Karsten Wedel

2007-01-01

72

Levels of processing: the evolution of a framework  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

73

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

74

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)

1989-01-01

75

A system-level, molecular evolutionary analysis of mammalian phototransduction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background Visual perception is initiated in the photoreceptor cells of the retina via the phototransduction system. This system has shown marked evolution during mammalian divergence in such complex attributes as activation time and recovery time. We have performed a molecular evolutionary analysis of proteins involved in mammalian phototransduction in order to unravel how the action of natural selection has been distributed throughout the system to evolve such traits. Results We fo...

Invergo, Brandon M.; Montanucci, Ludovica; Laayouni, Hafid; Bertranpetit, Jaume

2013-01-01

76

Explaining group-level traits requires distinguishing process from product.  

Science.gov (United States)

Smaldino is right to argue that we need a richer theory of group-level traits. He is wrong, however, in limiting group-level traits to units of cultural selection, which require explanations based on group selection. Traits are best understood when explanations focus on both process (i.e., selection) and product (i.e., adaptation). This approach can distinguish group-level traits that arise through within-group processes from those that arise through between-group processes. PMID:24970416

Panchanathan, Karthik; Mathew, Sarah; Perreault, Charles

2014-06-01

77

A Study of molecular cooling via Sisyphus processes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 an...

Comparat, Daniel

2011-01-01

78

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

79

The Algorithm Theoretical Basis Document for Level 1A Processing  

Science.gov (United States)

The first process of the Geoscience Laser Altimeter System (GLAS) Science Algorithm Software converts the Level 0 data into the Level 1A Data Products. The Level 1A Data Products are the time ordered instrument data converted from counts to engineering units. This document defines the equations that convert the raw instrument data into engineering units. Required scale factors, bias values, and coefficients are defined in this document. Additionally, required quality assurance and browse products are defined in this document.

Jester, Peggy L.; Hancock, David W., III

2012-01-01

80

Charge transfer processes: the role of optimized molecular orbitals.  

Science.gov (United States)

The influence of the molecular orbitals on charge transfer (CT) reactions is analyzed through wave function-based calculations. Characteristic CT processes in the organic radical 2,5-di-tert-butyl-6-oxophenalenoxyl linked with tetrathiafulvalene and the inorganic crystalline material LaMnO3 show that changes in the inner shells must be explicitly taken into account. Such electronic reorganization can lead to a reduction of the CT vertical transition energy up to 66%. A state-specific approach accessible through an adapted CASSCF (complete active space self-consistent field) methodology is capable of reaching good agreement with the experimental spectroscopy of CT processes. A partitioning of the relaxation energy in terms of valence- and inner-shells is offered and sheds light on their relative importance. This work paves the way to the intimate description of redox reactions using quantum chemistry methods. PMID:24781811

Meyer, Benjamin; Domingo, Alex; Krah, Tim; Robert, Vincent

2014-08-01

 
 
 
 
81

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)

2007-08-01

82

The Building Blocks of Materials: Gathering Knowledge at the Molecular Level  

Science.gov (United States)

Two start-up positions were created within SD46 to pursue developments in the rapidly expanding areas of biomineralization and nano-technology. As envisioned by Dr. Sandor Lehoczy, the new laboratories to be developed must have the capacity to investigate not only processes associated with the self-assembly of molecules but also the examination of self-assembled structures. For these purposes, laboratories capable of performing the intended function, particularly light scattering spectroscopy and atomic force microscopy were created. What follows then are recent advances arising from the development of these new laboratories. With the implementation of the Atomic Force Microscopy Facility, examples of investigations that determine a correlation between the molecular structure of materials and their macroscopic physical properties are provided. In addition, examples of investigations with particular emphasis on the physical properties of protein crystals, at the molecular level, and subsequent macroscopic characteristics are as provided. Finally, progress in fabrication of technology at the nano-scale levels at the developmental stage is also presented.

2003-01-01

83

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

84

Turning randomness into meaning at the molecular level using Muller's morphs  

Digital Repository Infrastructure Vision for European Research (DRIVER)

While evolutionary theory follows from observable facts and logical inferences (Mayr, 1985), historically, the origin of novel inheritable variations was a major obstacle to acceptance of natural selection (Bowler, 1992; Bowler, 2005). While molecular mechanisms address this issue (Jablonka and Lamb, 2005), analysis of responses to the Biological Concept Inventory (BCI) (Klymkowsky et al., 2010), revealed that molecular biology majors rarely use molecular level ideas in their discourse, imply...

Henson, Kathleen; Cooper, Melanie M.; Klymkowsky, Michael W.

2012-01-01

85

Protein adsorption on nanohydroxyapatites: spectroscopic investigations at molecular level  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Proper thermal treatments allowed to modify the number of surface Ca2+ able to coordinate water molecules on the surface of hydroxyapatite (HA) nanoparticles surrounded by an amorphous layer. Despite the consequent significant difference in the first hydration level between untreated and treated HA, the amount of adsorbed BSA, used as a model protein, remained essentially unchanged and the native structure of adsorbed protein was retained (as indicated by mid-IR ATR). Near-IR spectroscopy ev...

Bertinetti, Luca; Martra, Gianmario; Ceschino, Raffaella; Bollati, Daniele

2009-01-01

86

Tracing Nucleation and Growth on Atomic Level in Amorphous Sodium by Molecular Dynamics Simulation  

International Nuclear Information System (INIS)

Crystallization of amorphous Na is simulated by using the molecular dynamics method, and the evolutions of atomic clusters are traced by the cluster-type index method (CTIM) we proposed previously. It is demonstrated that the crystallization process exhibits three distinct stages of nucleation, subsequent growth of nuclei and coarsening of crystal grains. Both the size and the internal structure of a cluster play crucial roles in determining whether it is a nucleus. The cluster tracing analysis can identify different crystallization stages more clearly and accurately than other methods. Meanwhile, the simulation results can provide a reasonable explanation at an atomic level for the experimental phenomenon obtained previously. (condensed matter: structure, mechanical and thermal properties)

2010-03-01

87

Molecular Dynamics Simulation of Macromolecules Using Graphics Processing Unit  

CERN Document Server

Molecular dynamics (MD) simulation is a powerful computational tool to study the behavior of macromolecular systems. But many simulations of this field are limited in spatial or temporal scale by the available computational resource. In recent years, graphics processing unit (GPU) provides unprecedented computational power for scientific applications. Many MD algorithms suit with the multithread nature of GPU. In this paper, MD algorithms for macromolecular systems that run entirely on GPU are presented. Compared to the MD simulation with free software GROMACS on a single CPU core, our codes achieve about 10 times speed-up on a single GPU. For validation, we have performed MD simulations of polymer crystallization on GPU, and the results observed perfectly agree with computations on CPU. Therefore, our single GPU codes have already provided an inexpensive alternative for macromolecular simulations on traditional CPU clusters and they can also be used as a basis to develop parallel GPU programs to further spee...

Xu, Ji; Ge, Wei; Yu, Xiang; Yang, Xiaozhen; Li, Jinghai

2010-01-01

88

Molecular Surveillance of Viral Processes Using Silicon Nitride Membranes  

Directory of Open Access Journals (Sweden)

Full Text Available Here we present new applications for silicon nitride (SiN membranes to evaluate biological processes. We determined that 50-nanometer thin films of SiN produced from silicon wafers were sufficiently durable to bind active rotavirus assemblies. A direct comparison of SiN microchips with conventional carbon support films indicated that SiN performs equivalent to the traditional substrate to prepare samples for Electron Microscopy (EM imaging. Likewise, SiN films coated with Ni-NTA affinity layers concentrated rotavirus particles similarly to affinity-coated carbon films. However, affinity-coated SiN membranes outperformed glow-discharged conventional carbon films 5-fold as indicated by the number of viral particles quantified in EM images. In addition, we were able to recapitulate viral uncoating and transcription mechanisms directed onto the microchip surfaces. EM images of these processes revealed the production of RNA transcripts emerging from active rotavirus complexes. These results were confirmed by the functional incorporation of radiolabeled nucleotides into the nascent RNA transcripts. Collectively, we demonstrate new uses for SiN membranes to perform molecular surveillance on life processes in real-time.

Deborah F. Kelly

2013-03-01

89

Sequential Remediation Processes for a Low Level Pesticide Wastewater  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 co...

2012-01-01

90

Semiempirical and process-based global sea level projections  

Science.gov (United States)

review the two main approaches to estimating sea level rise over the coming century: physically plausible models of reduced complexity that exploit statistical relationships between sea level and climate forcing, and more complex physics-based models of the separate elements of the sea level budget. Previously, estimates of future sea level rise from semiempirical models were considerably larger than those from process-based models. However, we show that the most recent estimates of sea level rise by 2100 using both methods have converged, but largely through increased contributions and uncertainties in process-based model estimates of ice sheets mass loss. Hence, we focus in this paper on ice sheet flow as this has the largest potential to contribute to sea level rise. Progress has been made in ice dynamics, ice stream flow, grounding line migration, and integration of ice sheet models with high-resolution climate models. Calving physics remains an important and difficult modeling issue. Mountain glaciers, numbering hundreds of thousands, must be modeled by extensive statistical extrapolation from a much smaller calibration data set. Rugged topography creates problems in process-based mass balance simulations forced by regional climate models with resolutions 10-100 times larger than the glaciers. Semiempirical models balance increasing numbers of parameters with the choice of noise model for the observations to avoid overfitting the highly autocorrelated sea level data. All models face difficulty in separating out non-climate-driven sea level rise (e.g., groundwater extraction) and long-term disequilibria in the present-day cryosphere-sea level system.

Moore, John C.; Grinsted, Aslak; Zwinger, Thomas; Jevrejeva, Svetlana

2013-09-01

91

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

92

High-Level waste process and product data annotated bibliography  

International Nuclear Information System (INIS)

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

1996-01-01

93

Level of mechanization of production processes in injecting wells  

Energy Technology Data Exchange (ETDEWEB)

Based on the data of research of territorial scientific research vessels, active YeNV and calculations, an analysis was made of the level of mechanization of individual production processes in the sphere of well injection. Substantiated recommendations are made for by-phase mechanization of a number of operations.

Fomichev, V.S.; Ivanova, E.V.; Soshchnin, N.M.

1982-01-01

94

Regulation of leaf hydraulics: from molecular to whole plant levels  

Science.gov (United States)

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 rapidly in response to physiological or environmental factors such as leaf hydration, light, temperature, or nutrient supply. Differences in venation pattern provide a basis for variations in Kleaf during development and between species. On a short time (hour) scale, the hydraulic resistance of the vessels can be influenced by transpiration-induced cavitations, wall collapses, and changes in xylem sap composition. The extravascular compartment includes all living tissues (xylem parenchyma, bundle sheath, and mesophyll) that transport water from xylem vessels to substomatal chambers. Pharmacological inhibition and reverse genetics studies have shown that this compartment involves water channel proteins called aquaporins (AQPs) that facilitate water transport across cell membranes. In many plant species, AQPs are present in all leaf tissues with a preferential expression in the vascular bundles. The various mechanisms that allow adjustment of Kleaf to specific environmental conditions include transcriptional regulation of AQPs and changes in their abundance, trafficking, and intrinsic activity. Finally, the hydraulics of inner leaf tissues can have a strong impact on the dynamic responses of leaf water potential and stomata, and as a consequence on plant carbon economy and leaf expansion growth. The manipulation of these functions could help optimize the entire plant performance and its adaptation to extreme conditions over short and long time scales.

Prado, Karine; Maurel, Christophe

2013-01-01

95

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 towards 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.

TakeshiSakurai

2014-03-01

96

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

97

Vector-valued image processing by parallel level sets.  

Science.gov (United States)

Vector-valued images such as RGB color images or multimodal medical images show a strong interchannel correlation, which is not exploited by most image processing tools. We propose a new notion of treating vector-valued images which is based on the angle between the spatial gradients of their channels. Through minimizing a cost functional that penalizes large angles, images with parallel level sets can be obtained. After formally introducing this idea and the corresponding cost functionals, we discuss their Gâteaux derivatives that lead to a diffusion-like gradient descent scheme. We illustrate the properties of this cost functional by several examples in denoising and demosaicking of RGB color images. They show that parallel level sets are a suitable concept for color image enhancement. Demosaicking with parallel level sets gives visually perfect results for low noise levels. Furthermore, the proposed functional yields sharper images than the other approaches in comparison. PMID:23955746

Ehrhardt, Matthias Joachim; Arridge, Simon R

2014-01-01

98

Optimal degradation processes control by two-level policies  

International Nuclear Information System (INIS)

Two-level control policies are applied to various types of Markov processes describing degrading parameters of system units. To estimate the system operation cost an expectation of losses per unit time is evaluated. It is assumed that the degradation process is observable, and a monitoring system can signal about future failures. Firstly, semi-Markov processes are considered. A death process is proposed for a unit subjected to corrosion. A Markov chain are used for the problem of fatigue crack growth. The control problem is studied mainly in a steady-state regime for units of multiple use when the cost function is performed as the ratio of expectations. The cost function as the expectation of losses per unit time for single units is also studied, and the majorizing property of this cost function is shown

1999-10-01

99

Quantum information processing at the cellular level. Euclidean approach  

CERN Document Server

Application of quantum principles to living cells requires a new approximation of the full quantum mechanical description of intracellular dynamics. We discuss what principal elements any such good approximation should contain. As one such element, the notion of "Catalytic force" Cf is introduced. Cf is the effect of the molecular target of catalysis on the catalytic microenvironment that adjusts the microenvironment towards a state that facilitates the catalytic act. This phenomenon is experimentally testable and has an intriguing implication for biological organization and evolution, as it amounts to "optimization without natural selection of replicators". Unlike the statistical-mechanical approaches to self-organization, the Cf principle does not encounter the problem of "tradeoff between stability and complexity" at the level of individual cell. Physically, the Cf is considered as a harmonic-like force of reaction, which keeps the state of the cell close to the ground state, defined here as a state where ...

Ogryzko, Vasily

2009-01-01

100

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

2008-03-28

 
 
 
 
101

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

Science.gov (United States)

Here we report the bias-evolution of the electrical double layer structure of an ionic liquid on highly ordered pyrolytic graphite measured by atomic force microscopy. 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, which improves our understanding of the mechanism of charge storage on a molecular level. PMID:24215396

Black, Jennifer M; Walters, Deron; Labuda, Aleksander; Feng, Guang; Hillesheim, Patrick C; Dai, Sheng; Cummings, Peter T; Kalinin, Sergei V; Proksch, Roger; Balke, Nina

2013-12-11

102

Molecular processes from the AGB to the PN stage  

CERN Multimedia

Many complex organic molecules and inorganic solid-state compounds have been observed in the circumstellar shell of stars (both C-rich and O-rich) in the transition phase between Asymptotic Giant Branch (AGB) stars and Planetary Nebulae (PNe). This short (~100-10.000 years) phase of stellar evolution represents a wonderful laboratory for astrochemistry and provides severe constraints on any model of gas-phase and solid-state chemistry. One of the major challenges of present day astrophysics and astrochemistry is to understand the formation pathways of these complex organic molecules and inorganic solid-state compounds (e.g., polycyclic aromatic hydrocarbons, fullerenes, and graphene in the case of a C-rich chemistry and oxides and crystalline silicates in O-rich environments) in space. In this review, I present an observational review of the molecular processes in the late stages of stellar evolution with a special emphasis on the first detections of fullerenes and graphene in PNe.

Garcia-Hernandez, D A

2011-01-01

103

0-level Vacuum Packaging RT Process for MEMS Resonators  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 injecti...

Abele?, N.; Grogg, D.; Hibert, C.; Casset, F.; Ancey, P.; Ionescu, A.

2007-01-01

104

Effects of molecular structural variants on serum Krebs von den Lungen-6 levels in sarcoidosis  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Serum Krebs von den Lungen-6 (KL-6, which is classified as human mucin-1 (MUC1, is used as a marker of sarcoidosis and other interstitial lung diseases. However, there remain some limitations due to a lack of information on the factors contributing to increased levels of serum KL-6. This study was designed to investigate the factors contributing to increased levels of serum KL-6 by molecular analysis. Methods Western blot analysis using anti-KL-6 antibody was performed simultaneously on the bronchoalveolar lavage fluid (BALF and serum obtained from 128 subjects with sarcoidosis. Results KL-6/MUC1 in BALF showed three bands and five band patterns. These band patterns were associated with the MUC1 genotype and the KL-6 levels. KL-6/MUC1 band patterns in serum were dependent on molecular size class in BALF. Significantly increased levels of serum KL-6, serum/BALF KL-6 ratio and serum soluble interleukin 2 receptor were observed in the subjects with influx of high molecular size KL-6/MUC1 from the alveoli to blood circulation. The multivariate linear regression analysis involving potentially relevant variables such as age, gender, smoking status, lung parenchymal involvement based on radiographical stage and molecular size of KL-6/MUC1 in serum showed that the molecular size of KL-6/MUC1 in serum was significant independent determinant of serum KL-6 levels. Conclusions The molecular structural variants of KL-6/MUC1 and its leakage behavior affect serum levels of KL-6 in sarcoidosis. This information may assist in the interpretation of serum KL-6 levels in sarcoidosis.

Shigemura Masahiko

2012-07-01

105

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

106

Mixing Processes in High-Level Waste Tanks - Final Report  

Energy Technology Data Exchange (ETDEWEB)

The mixing processes in large, complex enclosures using one-dimensional differential equations, with transport in free and wall jets is modeled using standard integral techniques. With this goal in mind, we have constructed a simple, computationally efficient numerical tool, the Berkeley Mechanistic Mixing Model, which can be used to predict the transient evolution of fuel and oxygen concentrations in DOE high-level waste tanks following loss of ventilation, and validate the model against a series of experiments.

Peterson, P.F.

1999-05-24

107

Molecular dynamics study on Ar ion bombardment effects in amorphous SiO2 deposition processes  

International Nuclear Information System (INIS)

Argon ion bombardment effects on growing amorphous SiO2 films during reactive sputtering deposition processes were examined based on molecular dynamics (MD) and Monte Carlo (MC) simulation techniques. The system we have considered here is a film that is subject to energetic Ar bombardment while it is formed by surface reactions of Si and O atoms separately supplied at low kinetic energies. It has been found that (1) Ar injections preferentially sputter O atoms from the surface over Si and (2) also have a compressing effect on the growing film during the deposition process. In other words, our MD/MC simulations have demonstrated at the atomic level that, with higher energy Ar injections, an amorphous SiO2 film grown in a reactive sputtering deposition process is denser and more Si rich

2006-12-15

108

Fermi level alignment in molecular nanojunctions and its relation to charge transfer  

DEFF Research Database (Denmark)

The alignment of the Fermi level of a metal electrode within the gap of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of a molecule is a key quantity in molecular electronics, which can vary the electron transparency of a single-molecule junction by orders of magnitude. We present a quantitative analysis of the relation between this level alignment (which can be estimated from charging free molecules) and charge transfer for bipyridine and biphenyl dithiolate (BPDT) molecules attached to gold leads based on density functional theory calculations. For bipyridine the charge distribution is defined by a balance between electrostatic repulsion effects and the filling of the LUMO, where the molecule loses electrons to the leads. BPDT, on the other hand, gains electrons. As a direct consequence the Fermi level of the metal is found at the energetically higher end of the gap in the transmission function for bipyridine and at its lower end for BPDT.

Stadler, Robert; Jacobsen, Karsten Wedel

2006-01-01

109

Free energy calculations using dual-level Born-Oppenheimer molecular dynamics  

International Nuclear Information System (INIS)

We describe an efficient and accurate method to compute free energy changes in complex chemical systems that cannot be described through classical molecular dynamics simulations, examples of which are chemical and photochemical reactions in solution, enzymes, interfaces, etc. It is based on the use of dual-level Born-Oppenheimer molecular dynamics simulations. A low-level quantum mechanical method is employed to calculate the potential of mean force through the umbrella sampling technique. Then, a high-level quantum mechanical method is used to estimate a free energy correction on selected points of the reaction coordinate using perturbation theory. The precision of the results is comparable to that of ab initio molecular dynamics methods such as the Car-Parrinello approach but the computational cost is much lower, roughly by two to three orders of magnitude. The method is illustrated by discussing the association free energy of simple organometallic compounds, although the field of application is very broad.

2010-08-14

110

High level cognitive information processing in neural networks  

Science.gov (United States)

Two related research efforts were addressed: (1) high-level connectionist cognitive modeling; and (2) local neural circuit modeling. The goals of the first effort were to develop connectionist models of high-level cognitive processes such as problem solving or natural language understanding, and to understand the computational requirements of such models. The goals of the second effort were to develop biologically-realistic model of local neural circuits, and to understand the computational behavior of such models. In keeping with the nature of NASA's Innovative Research Program, all the work conducted under the grant was highly innovative. For instance, the following ideas, all summarized, are contributions to the study of connectionist/neural networks: (1) the temporal-winner-take-all, relative-position encoding, and pattern-similarity association techniques; (2) the importation of logical combinators into connection; (3) the use of analogy-based reasoning as a bridge across the gap between the traditional symbolic paradigm and the connectionist paradigm; and (4) the application of connectionism to the domain of belief representation/reasoning. The work on local neural circuit modeling also departs significantly from the work of related researchers. In particular, its concentration on low-level neural phenomena that could support high-level cognitive processing is unusual within the area of biological local circuit modeling, and also serves to expand the horizons of the artificial neural net field.

Barnden, John A.; Fields, Christopher A.

1992-01-01

111

FEATURES, EVENTS, AND PROCESSES: SYSTEM-LEVEL AND CRITICALITY  

Energy Technology Data Exchange (ETDEWEB)

The primary purpose of this Analysis/Model Report (AMR) is to identify and document the screening analyses for the features, events, and processes (FEPs) that do not easily fit into the existing Process Model Report (PMR) structure. These FEPs include the 3 1 FEPs designated as System-Level Primary FEPs and the 22 FEPs designated as Criticality Primary FEPs. A list of these FEPs is provided in Section 1.1. This AMR (AN-WIS-MD-000019) documents the Screening Decision and Regulatory Basis, Screening Argument, and Total System Performance Assessment (TSPA) Disposition for each of the subject Primary FEPs. This AMR provides screening information and decisions for the TSPA-SR report and provides the same information for incorporation into a project-specific FEPs database. This AMR may also assist reviewers during the licensing-review process.

D.L. McGregor

2000-12-20

112

Low level image processing techniques using the pipeline image processing engine in the flight telerobotic servicer  

Science.gov (United States)

The sensory processing system for the NASA/NBS Standard Reference Model (NASREM) for telerobotic control is described. This control system architecture was adopted by NASA of the Flight Telerobotic Servicer. The control system is hierarchically designed and consists of three parallel systems: task decomposition, world modeling, and sensory processing. The Sensory Processing System is examined, and in particular the image processing hardware and software used to extract features at low levels of sensory processing for tasks representative of those envisioned for the Space Station such as assembly and maintenance are described.

Nashman, Marilyn; Chaconas, Karen J.

1988-01-01

113

Single amino acid substitution in important hemoglobinopathies does not disturb molecular function and biological process  

Directory of Open Access Journals (Sweden)

Full Text Available Viroj WiwanitkitDepartment of Laboratory Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, ThailandAbstract: Hemoglobin is an important protein found in the red cells of many animals. In humans, the hemoglobin is mainly distributed in the red blood cell. Single amino acid substitution is the main pathogenesis of most hemoglobin disorders. Here, the author used a new gene ontology technology to predict the molecular function and biological process of four important hemoglobin disorders with single substitution. The four studied important abnormal hemoglobins (Hb with single substitution included Hb S, Hb E, Hb C, and Hb J-Baltimore. Using the GoFigure server, the molecular function and biological process in normal and abnormal hemoglobins was predicted. Compared with normal hemoglobin, all studied abnormal hemoglobins had the same function and biological process. This indicated that the overall function of oxygen transportation is not disturbed in the studied hemoglobin disorders. Clinical findings of oxygen depletion in abnormal hemoglobin should therefore be due to the other processes rather than genomics, proteomics, and expression levels.Keywords: hemoglobin, amino acid, substitution, function

Viroj Wiwanitkit

2008-06-01

114

SENTINEL-2 Level 1 Products and Image Processing Performances  

Science.gov (United States)

In partnership with the European Commission and in the frame of the Global Monitoring for Environment and Security (GMES) program, the European Space Agency (ESA) is developing the Sentinel-2 optical imaging mission devoted to the operational monitoring of land and coastal areas. The Sentinel-2 mission is based on a satellites constellation deployed in polar sun-synchronous orbit. While ensuring data continuity of former SPOT and LANDSAT multi-spectral missions, Sentinel-2 will also offer wide improvements such as a unique combination of global coverage with a wide field of view (290 km), a high revisit (5 days with two satellites), a high resolution (10 m, 20 m and 60 m) and multi-spectral imagery (13 spectral bands in visible and shortwave infra-red domains). In this context, the Centre National d'Etudes Spatiales (CNES) supports ESA to define the system image products and to prototype the relevant image processing techniques. This paper offers, first, an overview of the Sentinel-2 system and then, introduces the image products delivered by the ground processing: the Level-0 and Level-1A are system products which correspond to respectively raw compressed and uncompressed data (limited to internal calibration purposes), the Level-1B is the first public product: it comprises radiometric corrections (dark signal, pixels response non uniformity, crosstalk, defective pixels, restoration, and binning for 60 m bands); and an enhanced physical geometric model appended to the product but not applied, the Level-1C provides ortho-rectified top of atmosphere reflectance with a sub-pixel multi-spectral and multi-date registration; a cloud and land/water mask is associated to the product. Note that the cloud mask also provides an indication about cirrus. The ground sampling distance of Level-1C product will be 10 m, 20 m or 60 m according to the band. The final Level-1C product is tiled following a pre-defined grid of 100x100 km2, based on UTM/WGS84 reference frame. The stringent image quality requirements are also described, in particular the geo-location accuracy for both absolute (better than 12.5 m) and multi-temporal (better than 0.3 pixels) cases. Then, the prototyped image processing techniques (both radiometric and geometric) will be addressed. The radiometric corrections will be first introduced. They consist mainly in dark signal and detector relative sensitivity correction, crosstalk correction and MTF restoration. Then, a special focus will be done on the geometric corrections. In particular the innovative method of automatic enhancement of the geometric physical model will be detailed. This method takes advantage of a Global Reference Image database, perfectly geo-referenced, to correct the physical geometric model of each image taken. The processing is based on an automatic image matching process which provides accurate ground control points between a given band of the image to refine and a reference image, allowing to dynamically calibrate the viewing model. The generation of the Global Reference Image database made of Sentinel-2 pre-calibrated mono-spectral images will be also addressed. In order to perform independent validation of the prototyping activity, an image simulator dedicated to Sentinel-2 has been set up. Thanks to this, a set of images have been simulated from various source images and combining different acquisition conditions and landscapes (mountains, deserts, cities …). Given disturbances have been also simulated so as to estimate the end to end performance of the processing chain. Finally, the radiometric and geometric performances obtained by the prototype will be presented. In particular, the geo-location performance of the level-1C products which widely fulfils the image quality requirements will be provided.

Baillarin, S. J.; Meygret, A.; Dechoz, C.; Petrucci, B.; Lacherade, S.; Tremas, T.; Isola, C.; Martimort, P.; Spoto, F.

2012-07-01

115

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

116

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

International Nuclear Information System (INIS)

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. The terminal waste form processes considered were: borosilicate glass, low-alkali glass, marbles-in-lead matrix, and crystallinolecular potential and molecular dynamics calculations of the effect are yet to be completed. Cous oxide was also investigated. The reaction is first order in nitrite ion, second order in hydrogen ion, and between zero and first order in hydroxylamine monosulfonate, depending on the concentration

1981-01-01

117

Molecular responses during cadmium-induced stress in Daphnia magna: Integration of differential gene expression with higher-level effects  

International Nuclear Information System (INIS)

DNA microarrays offer great potential in revealing insight into mechanistic toxicity of contaminants. The aim of the present study was (i) to gain insight in concentration- and time-dependent cadmium-induced molecular responses by using a customized Daphnia magna microarray, and (ii) to compare the gene expression profiles with effects at higher levels of biological organization (e.g. total energy budget and growth). Daphnids were exposed to three cadmium concentrations (nominal value of 10, 50, 100 ?g/l) for two time intervals (48 and 96 h). In general, dynamic expression patterns were obtained with a clear increase of gene expression changes at higher concentrations and longer exposure duration. Microarray analysis revealed cadmium affected molecular pathways associated with processes such as digestion, oxygen transport, cuticula metabolism and embryo development. These effects were compared with higher-level effects (energy budgets and growth). For instance, next to reduced energy budgets due to a decline in lipid, carbohydrate and protein content, we found an up-regulated expression of genes related to digestive processes (e.g. ?-esterase, cellulase, ?-amylase). Furthermore, cadmium affected the expression of genes coding for proteins involved in molecular pathways associated with immune response, stress response, cell adhesion, visual perception and signal transduction in the present study

2007-07-20

118

Impact of Altimeter Data Processing on Sea Level Studies  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study addresses the impact of satellite altimetry data processing on sea levelstudies at regional scale, with emphasis on the influence of various geophysical correctionsand satellite orbit on the structure of the derived interannual signal and sea level trend. Thework focuses on the analysis of TOPEX data for a period of over twelve years, for threeregions in the North Atlantic: Tropical (0o≤φ≤25o), Sub-Tropical (25o≤φâ‰...

Joana Fernandes, M.; Susana Barbosa; Clara Lázaro

2006-01-01

119

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

120

Process modeling of low-level mixed waste vitrification systems  

International Nuclear Information System (INIS)

Chemical process simulators have the potential to combine, in a single calculation, thermodynamic modeling of glass melters with vitrification system material and energy balances. These commercially-available computer codes have been developed for process simulation in the chemical and petroleum industries, i.e., processes which occur primarily in the vapor and liquid phases. As such, they are not oriented towards solid-liquid transition phenomena. They are capable of tracking solids, however, and contain algorithms for complex phase and chemical equilibrium similar to those which underlie codes used in metallurgical thermodynamics. One such chemical process simulator, ASPEN+trademark, is being used to model melter thermodynamics for low-level mixed waste (LLMW) vitrification systems. Such systems are now under development by the Savannah River Technology Center (SRTC) in cooperation with the DOE/Industrial Center for Vitrification Research at Clemson University. This paper reports glass melter model calculations using ASPEN+trademark and compares this tool to STGSOL, a modeling tool which is widely used for high-temperature thermodynamic equilibrium calculations for smelters and glass melters

1994-04-25

 
 
 
 
121

Oak Ridge Y-12 Plant Emergency Action Level (EAL) Process  

Energy Technology Data Exchange (ETDEWEB)

This report establishes requirements and standard methods for the development and maintenance of the Emergency Action Level (EAL) Process used by all lead and event contractors for emergency planning and preparedness. The EAL process ensures a technically defensible approach to emergency categorization/classification in accordance with DOE Order 151.1. The instructions provided in this document include methods and requirements for the development and approval of the EAL process. EALs are developed to cover events inside and outside the Y-12 Plant and to allow the Emergency Response Organization (ERO) to classify or reclassify events promptly based on specific indicators. This report is divided into the following 11 subsections: (1) EAL Process, (2) Categorization/Classification System for Operational Emergencies, (3) Development of EALs, (4) Barrier Analysis for EALs, (5) Symptom-Based and Event-Based EALs, (6) Other Considerations, (7) Integration of EALs with Normal and Off-Normal Operations, (8) EAL Manual, (9) Testing EALs for Completeness, (10) Training and Implementation of EALs, and (11) Configuration Management.

Bailiff, E.G.; Bolling, J.D.

2000-08-01

122

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 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)

2002-09-26

123

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

124

EOS MLS Level 1B Data Processing Software. Version 3  

Science.gov (United States)

This software is an improvement on Version 2, which was described in EOS MLS Level 1B Data Processing, Version 2.2, NASA Tech Briefs, Vol. 33, No. 5 (May 2009), p. 34. It accepts the EOS MLS Level 0 science/engineering data, and the EOS Aura spacecraft ephemeris/attitude data, and produces calibrated instrument radiances and associated engineering and diagnostic data. This version makes the code more robust, improves calibration, provides more diagnostics outputs, defines the Galactic core more finely, and fixes the equator crossing. The Level 1 processing software manages several different tasks. It qualifies each data quantity using instrument configuration and checksum data, as well as data transmission quality flags. Statistical tests are applied for data quality and reasonableness. The instrument engineering data (e.g., voltages, currents, temperatures, and encoder angles) is calibrated by the software, and the filter channel space reference measurements are interpolated onto the times of each limb measurement with the interpolates being differenced from the measurements. Filter channel calibration target measurements are interpolated onto the times of each limb measurement, and are used to compute radiometric gain. The total signal power is determined and analyzed by each digital autocorrelator spectrometer (DACS) during each data integration. The software converts each DACS data integration from an autocorrelation measurement in the time domain into a spectral measurement in the frequency domain, and estimates separately the spectrally, smoothly varying and spectrally averaged components of the limb port signal arising from antenna emission and scattering effects. Limb radiances are also calibrated.

Perun, Vincent S.; Jarnot, Robert F.; Wagner, Paul A.; Cofield, Richard E., IV; Nguyen, Honghanh T.; Vuu, Christina

2011-01-01

125

Electron collision processes in atomic and molecular physics  

International Nuclear Information System (INIS)

Interaction of electro-magnetic radiation with atoms, molecules and cluster constitutes a major field of research in physical, chemical and biological sciences in recent years. Progress in atomic molecular and optical physics has made a significant impact on mankind in the 21st century. Most of the technological growth, such as electronic communications, computers etc., are due to significant developments in atomic and quantum physics. This conference provides an opportunity for students, researchers and teachers to interact with other scientists of high repute and fame and helps to abreast of the latest developments and advancements in the fields of Atomic, Molecular and Optical Physics. Papers relevant to INIS are indexed separately

2013-01-01

126

Driving Ordering Processes in Molecular-Dynamics Simulations  

Science.gov (United States)

Self-organized criticality describes the emergence of complexity in dynamical nonequilibrium systems. In this paper we introduce a unique approach whereby a driven energy conversion is utilized as a sampling bias for ordered arrangements in molecular dynamics simulations of atomic and molecular fluids. This approach gives rise to dramatically accelerated nucleation rates, by as much as 30 orders of magnitude, without the need of predefined order parameters, which commonly employed rare-event sampling methods rely on. The measured heat fluxes suggest how the approach can be generalized.

Dittmar, Harro; Kusalik, Peter G.

2014-05-01

127

Improving wafer level CD uniformity for logic applications utilizing mask level metrology and process  

Science.gov (United States)

Critical Dimension Uniformity (CDU) is one of the key parameters necessary to assure good performance and reliable functionality of any integrated circuit (IC). The extension of 193nm based lithography usage combined with design rule shrinkage makes process control, in particular the wafer level CDU control, an extremely important and challenging task in IC manufacturing. In this study the WLCD-CDC closed loop solution offered by Carl Zeiss SMS was examined. This solution aims to improve the wafer level intra-field CDU without the need to run wafer prints and extensive wafer CD metrology. It combines two stand-alone tools: The WLCD tool which measures CD based on aerial imaging technology while applying the exact scanner-used illumination conditions to the photomask and the CDC tool which utilizes an ultra-short femto-second laser to write intra-volume shading elements (Shade-In Elements™) inside the photomask bulk material. The CDC process changes the dose going through the photomask down to the wafer, hence the wafer level intra-field CDU improves. The objective of this study was to evaluate how CDC process is affecting the CD for different type of features and pattern density which are typical for logic and system on chip (SOC) devices. The main findings show that the linearity and proximity behavior is maintained by the CDC process and CDU and CDC Ratio (CDCR) show a linear behavior for the different feature types. Finally, it was demonstrated that the CDU errors of the targeted (critical) feature have been effectively eliminated. In addition, the CDU of all other features have been significantly improved as well.

Cohen, Avi; Trautzsch, Thomas; Buttgereit, Ute; Graitzer, Erez; Hanuka, Ori

2013-09-01

128

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

129

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 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)

2006-09-18

130

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

Directory of Open Access Journals (Sweden)

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 problem 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

2010-09-01

131

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

132

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 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)

2008-08-12

133

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

2011-06-20

134

EOS MLS Level 2 Data Processing Software Version 3  

Science.gov (United States)

This software accepts the EOS MLS calibrated measurements of microwave radiances products and operational meteorological data, and produces a set of estimates of atmospheric temperature and composition. This version has been designed to be as flexible as possible. The software is controlled by a Level 2 Configuration File that controls all aspects of the software: defining the contents of state and measurement vectors, defining the configurations of the various forward models available, reading appropriate a priori spectroscopic and calibration data, performing retrievals, post-processing results, computing diagnostics, and outputting results in appropriate files. In production mode, the software operates in a parallel form, with one instance of the program acting as a master, coordinating the work of multiple slave instances on a cluster of computers, each computing the results for individual chunks of data. In addition, to do conventional retrieval calculations and producing geophysical products, the Level 2 Configuration File can instruct the software to produce files of simulated radiances based on a state vector formed from a set of geophysical product files taken as input. Combining both the retrieval and simulation tasks in a single piece of software makes it far easier to ensure that identical forward model algorithms and parameters are used in both tasks. This also dramatically reduces the complexity of the code maintenance effort.

Livesey, Nathaniel J.; VanSnyder, Livesey W.; Read, William G.; Schwartz, Michael J.; Lambert, Alyn; Santee, Michelle L.; Nguyen, Honghanh T.; Froidevaux, Lucien; wang, Shuhui; Manney, Gloria L.; Wu, Dong L.; Wagner, Paul A.; Vuu, Christina; Pumphrey, Hugh C.

2011-01-01

135

Molecular Ion Dissociation Processes in a Partially Cooled Electrostatic Trap  

Science.gov (United States)

An experimental capability being developed at the Oak Ridge National Laboratory Multi-Charged Ion Research Facility (ORNL MIRF) is described that enables stored cooling and state characterization of atomic and molecular ions of essentially any mass. Ions selected from a variety of available (hot and cold) sources are injected into a 1.5 meter long electrostatic mirror trap, in which excited internal states decay by radiative cooling. Ion lifetime studies or direct measurements of 'in-trap' interactions of molecular ions with electrons or atomic targets are accomplished with either a crossed electron beam or atomic beam (with recoil ion detection) located in the field-free region of the ion-trap, coupled with product velocity imaging. Similarly, extraction of trap-cooled ions can be used 'out-of-trap' for near state-specific electron capture (EC) and dissociative charge exchange (DCE) studies employing higher resolution COLTRIMS techniques coupled with fragment imaging.

Vane, C. R.; Bannister, M. E.; Deng, S.; Fogle, M.; Thomas, R. D.

2011-07-01

136

Levels and Atypical Evolutions of the Romanian Demographic Processes  

Directory of Open Access Journals (Sweden)

Full Text Available Within the XXth century, especially in the second half thereof, the approach views of the relation between the population and economy (both of them regarded in dynamics have multiplied themselves, the points of view as regards this subject becoming not only much more diverse but also opposite. All these views are characterised by the population transformation in endogenous factor (in internal, intrinsic side of the economic development (of the economic growth, factor that, at its turn, is determined by the economic processes. The double position of the population in the demo-economical relations system - as main production factor and as virtual recipient of produced goods - is a strong argument in the favour of the demographic factor as endogenous factor of growth and economic development. The correlations between the two variables are diverse and very difficultly to be quantified. It is known that the effect of the demographic impact upon the economic factor is felt after many years from the date of the demo-economic phenomenon occurring. So, within the last decades, the research intended to identify certain essential, durable relations between the population evolution and the economic growth became more intensive. On this line there are presented atypical evolutions and levels of demographic processes in Romania.

Mirela Ionela Aceleanu

2007-01-01

137

Study on Removal of Organics of Different Molecular Weight by Coagulation-Membrane Filtration Process  

Directory of Open Access Journals (Sweden)

Full Text Available This paper compares the difference in membrane flux between direct membrane filtration and coagulation-membrane filtration, and investigates the removal of organics of different molecular weight by coagulation-membrane filtration process, in turn studies the fouling removal mechanism of coagulation process. The results indicate that for COD removal from raw water, coagulation is effective mainly on the organics of molecular weight higher than 10 kDa, and membrane filtration is effective mainly on the organics of molecular weight between 30 kDa and 100 kDa and higher than 100 kDa; as for UV254 removal, coagulation is effective mainly on the organics of high molecular weight, and membrane filtration is effective mainly on the organics of molecular weight between 1 kDa and 100 kDa. Therefore, it proves that the high molecular organics are mainly responsible for the membrane fouling.

Lin Yang

2010-02-01

138

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

139

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

140

Design and synthesis of molecular donors for solution-processed high-efficiency organic solar cells.  

Science.gov (United States)

Organic semiconductors incorporated into solar cells using a bulk heterojunction (BHJ) construction show promise as a cleaner answer to increasing energy needs throughout the world. Organic solar cells based on the BHJ architecture have steadily increased in their device performance over the past two decades, with power conversion efficiencies reaching 10%. Much of this success has come with conjugated polymer/fullerene combinations, where optimized polymer design strategies, synthetic protocols, device fabrication procedures, and characterization methods have provided significant advancements in the technology. More recently, chemists have been paying particular attention to well-defined molecular donor systems due to their ease of functionalization, amenability to standard organic purification and characterization methods, and reduced batch-to-batch variability compared to polymer counterparts. There are several critical properties for efficient small molecule donors. First, broad optical absorption needs to extend towards the near-IR region to achieve spectral overlap with the solar spectrum. Second, the low lying highest occupied molecular orbital (HOMO) energy levels need to be between -5.2 and -5.5 eV to ensure acceptable device open circuit voltages. Third, the structures need to be relatively planar to ensure close intermolecular contacts and high charge carrier mobilities. And last, the small molecule donors need to be sufficiently soluble in organic solvents (?10 mg/mL) to facilitate solution deposition of thin films of appropriate uniformity and thickness. Ideally, these molecules should be constructed from cost-effective, sustainable building blocks using established, high yielding reactions in as few steps as possible. The structures should also be easy to functionalize to maximize tunability for desired properties. In this Account, we present a chronological description of our thought process and design strategies used in the development of highly efficient molecular donors that achieve power conversion efficiencies greater than 7%. The molecules are based on a modular D(1)-A-D(2)-A-D(1) architecture, where A is an asymmetric electron deficient heterocycle, which allowed us to quickly access a library of compounds and develop structure-property-performance relationships. Modifications to the D1 and D2 units enable spectral coverage throughout the entire visible region and control of HOMO energy levels, while adjustments to the pendant alkyl substituents dictate molecular solubility, thermal transition temperatures, and solid-state organizational tendencies. Additionally, we discuss regiochemical considerations that highlight how individual atom placements can significantly influence molecular and subsequently device characteristics. Our results demonstrate the utility of this architecture for generating promising materials to be integrated into organic photovoltaic devices, call attention to areas for improvement, and provide guiding principles to sustain the steady increases necessary to move this technology forward. PMID:23984626

Coughlin, Jessica E; Henson, Zachary B; Welch, Gregory C; Bazan, Guillermo C

2014-01-21

 
 
 
 
141

Unexpected high levels of molecular chlorine observed at Barrow in spring 2009 during OASIS  

Science.gov (United States)

Very high levels of molecular chlorine (Cl2) (up to ~400 pptv) and very little bromine monochloride (BrCl) were observed at Barrow, AK during the ocean-atmosphere- sea ice-snowpack (OASIS) campaign. Diurnal profiles of Cl2 were observed with maximum levels in the early morning and late afternoon and no significant concentrations at night. BrCl was only detected when Cl2 was present. We suggest that BrCl is likely produced from heterogeneous reaction of chlorine compounds (e.g. Cl2, hypochlorous acid (HOCl) or hydrogen chloride (HCl)). The ultimate source of the molecular chlorine was not established but it was found to depend on ozone and actinic flux. The observed HCl levels were generally consistent with HCl levels predicted from the observed Cl2. HOCl concentrations derived from the observed Cl2 were much lower than the observed Cl2 levels. A time dependent model will be used to simulate the average diurnal profiles of Cl2, HOCl, ClO, HCl, and BrCl and investigate the chemical production and loss rates to sustain the diurnal profiles of Cl2 and BrCl. High levels of Cl2 have a significant impact on ozone loss and methane oxidation. Cl atom produced from Cl2 is the dominant oxidant of methane at Barrow in spring. More measurements of Cl2 are needed to investigate whether Cl2 is ubiquitous in polar regions.

Liao, J.; Huey, L. G.; Tanner, D.; Shepson, P. B.; Stephens, C. R.; Flocke, F. M.; Orlando, J. J.; Apel, E. C.; Fried, A.; Weinheimer, A. J.; Knapp, D. J.; Montzka, D.; Hall, S. R.; Ullmann, K.

2011-12-01

142

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

143

Molecular-level engineering of protein physical hydrogels for predictive sol-gel phase behavior  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Predictable tuning of bulk mechanics from the molecular level remains elusive in many physical hydrogel systems due to the reliance on non-specific and non-stoichiometric chain interactions for network formation. We describe a Mixing-Induced Two-Component Hydrogel (MITCH) system, in which network assembly is driven by specific and stoichiometric peptide-peptide binding interactions. By integrating protein science methodologies with simple polymer physics model, we manipulate the polypeptide b...

Mulyasasmita, Widya; Lee, Ji Seok; Heilshorn, Sarah C.

2011-01-01

144

Multifragmentation process in HIC simulated by modified quantum molecular dynamics  

International Nuclear Information System (INIS)

The collision dynamics and yields of the multifragmentation in intermediate energy heavy ion collisions are simulated within the frame of the modified quantum molecular dynamics (MQMD). With this new MQMD, the obvious improvements about the agreements between the experimental data and the simulating results for the fragment production by means of MDI and Pauli potential are achieved. Meanwhile the different influences of MDI and Pauli potential on the collision dynamics of intermediate energy heavy ion collisions are obtained. Finally the possible reasons for the discrepancies between the experimental data and the present simulating results and remedies of these deficiencies are discussed in detail

1995-11-01

145

Deep level spectra of ZnTe:Cr2+ layers grown by molecular beam epitaxy  

International Nuclear Information System (INIS)

ZnTe:Cr2+ epilayers grown by molecular beam epitaxy and doped both from elemental chromium and CrI3 compound source have been studied by deep level current transient spectroscopy. The center with the activation energy of (1.09 ± 0.03) eV that was brought about by a Cr2+-Cr+ transition under the excitation by electric field has been revealed. The chromium doping from CrI3 source leads to disappearance of some point defects typical for ZnTe thin films, the contamination level of grown epilayers with iodine being rather high

2002-05-01

146

Molecular Level Investigation of the Film Structure of a High Electron Mobility Copolymer via Vibrational Spectroscopy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Vibrational spectroscopy is adopted to investigate the film structure of poly{[N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} (P(NDI2OD-T2)) at the molecular level. Both Raman and IR spectra are measured for P(NDI2OD-T2) solutions and films. A good match with density functional theory (DFT) calculations at the B3LYP/6-311G** level is obtained, so that the main spectral features could be assigned. No significant spectral shifts are recorde...

2013-01-01

147

Molecular imaging with radionuclides, a powerful technique for studying biological processes in vivo  

International Nuclear Information System (INIS)

Our team is carrying on a systematic study devoted to the design of a SPECT detector with submillimeter resolution and adequate sensitivity (1 cps/kBq). Such system will be used for functional imaging of biological processes at molecular level in small animal. The system requirements have been defined by two relevant applications: study of atherosclerotic plaques characterization and stem cells diffusion and homing. In order to minimize costs and implementation time, the gamma detector will be based-as much as possible-on conventional components: scintillator crystal and position sensitive PhotoMultipliers read by individual channel electronics. A coded aperture collimator should be adapted to maximize the efficiency. The optimal selection of the detector components is investigated by systematic use of Monte-Carlo simulations (and laboratory validation tests); and finally preliminary results are presented and discussed here

2007-02-01

148

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

149

The SYNROC process for immobilizing high-level nuclear wastes  

International Nuclear Information System (INIS)

The status of the SYNROC process for immobilizing high-level wastes from reprocessed commercial nuclear power reactor fuel is described. The variant of SYNROC designed for this purpose is SYNROC-C; other variants, SYNROC-B,-D,-E and -F, are not discussed in detail. Long-term, quasi-dynamic aqueous leaching tests at 95 to 200 deg. C show that after 10 to 20 days, SYNROC-C is 500 to 10 000 times more resistant to leaching than borosilicate waste glass. The effects of radiation damage on SYNROC phases have been assessed by studying natural zirconolites and perovskites that have experienced large ?-radiation doses from contained radioactive elements over geological time; the doses are often far greater than SYNROC would receive in 1 million years. Isotopic studies show that these minerals, although metamict, have quantitatively retained U, Th and daughter products. In a parallel study, SYNROC-B, SYNROC-C and their constituent phases have been subjected to fast neutron irradiation, simulating 1 million years of SYNROC-C ageing. Volume expansions were observed but all specimens remained intact. The Australian Government is supporting a joint Australian Atomic Energy Commission/Australian National University project which will lead to the construction of a demonstration plant for the production of SYNROC containing simulated non-radioactive waste. The production rate will be about 20 kg of SYNROC per hour and the plant is scheduled to go into operation in 1985. The conceptual flowsheet involves the uniaxial hot pressing of SYNROC containing 2% of admixed fine Ti metal powder in unsupported thin-walled stainless-steel cans with a bellows configuration. The SYNROC process claims to offer several advantages over the current technologies for borosilicate waste glass manufacture. (author)

1983-05-16

150

Phase behaviour of macromolecular liquid crystalline materials. Computational studies at the molecular level  

International Nuclear Information System (INIS)

Molecular simulations provide an increasingly useful insight into the static and dynamic characteristics of materials. In this thesis molecular simulations of macro-molecular liquid crystalline materials are reported. The first liquid crystalline material that has been investigated is a side chain liquid crystal polymer (SCLCP). In this study semi-atomistic molecular dynamics simulations have been conducted at a range of temperatures and an aligning potential has been applied to mimic the effect of a magnetic field. In cooling the SCLCP from an isotropic melt, microphase separation was observed yielding a domain structure. The application of a magnetic field to this structure aligns the domains producing a stable smectic mesophase. This is the first study in which mesophases have been observed using an off-lattice model of a SCLCP. The second material that has been investigated is a dendrimer with terminal mesogenic functionalization. Here, a multi-scale approach has been taken with Monte Carlo studies of a single dendrimer molecule in the gas phase at the atomistic level, semi-atomistic molecular dynamics of a single molecule in liquid crystalline solvents and a coarse-grained molecular dynamics study of the dendrimer in the bulk. The coarse-grained model has been developed and parameterized using the results of the atomistic and semi-atomistic work. The single molecule studies showed that the liquid crystalline dendrimer was able to change its structure by conformational changes in the flexible chains that link the mesogenic groups to the core. Structural change was seen under the application of a mean field ordering potential in the gas phase, and in the presence of liquid crystalline solvents. No liquid crystalline phases were observed for the bulk phase studies of the coarse-grained model. However, when the length of the mesogenic units was increased there was some evidence for microphase separation in these systems. (author)

2003-01-01

151

Applying CLIPS to control of molecular beam epitaxy processing  

Science.gov (United States)

A key element of U.S. industrial competitiveness in the 1990's will be the exploitation of advanced technologies which involve low-volume, high-profit manufacturing. The demands of such manufacture limit participation to a few major entities in the U.S. and elsewhere, and offset the lower manufacturing costs of other countries which have, for example, captured much of the consumer electronics market. One such technology is thin-film epitaxy, a technology which encompasses several techniques such as Molecular Beam Epitaxy (MBE), Chemical Beam Epitaxy (CBE), and Vapor-Phase Epitaxy (VPE). Molecular Beam Epitaxy (MBE) is a technology for creating a variety of electronic and electro-optical materials. Compared to standard microelectronic production techniques (including gaseous diffusion, ion implantation, and chemical vapor deposition), MBE is much more exact, though much slower. Although newer than the standard technologies, MBE is the technology of choice for fabrication of ultraprecise materials for cutting-edge microelectronic devices and for research into the properties of new materials.

Rabeau, Arthur A.; Bensaoula, Abdelhak; Jamison, Keith D.; Horton, Charles; Ignatiev, Alex; Glover, John R.

1990-01-01

152

Procedure level data flow processing on dynamic structure multimicroprocessors  

Energy Technology Data Exchange (ETDEWEB)

Topstar, a highly parallel multi-microprocessor system is designed and constructed. It executes procedure level data flow processing (one data flow node is one procedure). Topstar is composed of two kinds of modules (CMS and PMS). Each module is a conventional micro computer system. The connective structure of Topstar is a locally connected bipartite graph. The control right belongs to each CM (which keeps unenabled data), and distributed control mechanism is attained. The load balancing problem is solved by the free competition rule. Five kinds of basic nodes are prepared for programming in the data flow graph language. Most Petri nets, involved in the free-choice Petri net subclass, can be realized by using these basic nodes. System software is implemented. The overflow in data buffers is avoided by introducing inhibitors (of the Petri net). Plural data buffers are attached to each node, and tokens can get ahead of others to provide more pipeline parallelism. Several program structures (such as conditional branch, loop and recursion) are available. Topstar-II consisting of 24 microprocessors is constructed and working with some applications. They are parallel mergesort, simulation of logical circuits, some arithmetic calculation, etc. Actually measured results in the case of parallel merge-sort are also reported. 9 references.

Suzuki, T.; Kurihara, K.; Tanaka, H.; Moto-oka, T.

1982-01-01

153

Hanford low-level waste process chemistry testing data package  

Energy Technology Data Exchange (ETDEWEB)

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 principle{close_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 & 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).

Smith, H.D.; Tracey, E.M.; Darab, J.G.; Smith, P.A.

1996-03-01

154

Steered molecular dynamics simulations on the "tail helix latch" hypothesis in the gelsolin activation process.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The molecular basis of the "tail helix latch" hypothesis in the gelsolin activation process has been studied by using the steered molecular dynamics simulations. In the present nanosecond scale simulations, the tail helix of gelsolin was pulled away from the S2 binding surface, and the required forces were calculated, from which the properties of binding between the tail helix and S2 domain and their dynamic unbinding processes were obtained. The force profile provides a detailed rupture mech...

Cheng, Feng; Shen, Jianhua; Luo, Xiaomin; Jiang, Hualiang; Chen, Kaixian

2002-01-01

155

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

1987-01-01

156

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

1987-03-01

157

Molecular dynamics simulation of Ga+ ion collision process  

International Nuclear Information System (INIS)

Molecular dynamics (MD) simulations of 30 keV accelerated Ga ions has been carried out, colliding with a Si surface. Using this procedure the amorphous structural region of the Si was found to expand with the progression of the interface region, that lie between the amorphous structure and the crystalline structure, as fluence increased in the depth direction. The height of the structure is increased and has a peak value around 1.6 × 1015 ion/cm2, the height becomes the negative value beyond the peak, that is, the phenomenon changes from a deformation to a remove. The tendency of distribution for height and depth is a good agreement with an experimental data

2013-07-15

158

Molecular analysis of the bacillus subtilis transformation process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Transformation of Bacillus subtilis presents an interesting model system for the study of DNA uptake and recombination in gram-positive bacteria. This dissertation deals with several aspects of these fundamental processes. After a brief introduction into the relevant literature of transformation and the use of plasmids in B. subtilis, experiments are described aimed at 1) the elucidation of the mechanism of uptake and processing of plasmid DNA and 2) the identification and functional analysis...

Vos, Willem Meindert

1983-01-01

159

Molecular Specificity of Multiple Hippocampal Processes Governing Fear Extinction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Over many years, fear extinction has been conceptualized as one dominant process, new inhibitory learning, which serves to dampen previously acquired fear. Here we present an alternative view, that brain region-specific processing of representations, expectations and emotional attributes of the fear-provoking event, recruits unique mechanisms that interdependently contribute to the conditioning and extinction of fear. The co-occurrence of these mechanisms within the fear circuit can thus be t...

2010-01-01

160

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

 
 
 
 
161

Molecular MRI differentiation of VEGF receptor-2 levels in C6 and RG2 glioma models.  

Science.gov (United States)

Vascular endothelial growth factor receptor 2 (VEGFR2) is an important angiogenic marker over-expressed in gliomas. With the use of molecular magnetic resonance imaging (mMRI) differing levels of VEGFR2 can be characterized in vivo with in rodent gliomas varying in angiogenesis. VEGFR2 levels were assessed by intravenous administration of an anti-VEGFR2 probe (anti-VEGFR2-albumin-Gd (gadolinium)-DTPA (diethylene triamine penta acetic acid)-biotin) into C6 or RG2 glioma-bearing rats, and visualized with mMRI. A non-specific IgG was coupled to the albumin-Gd-DTPA-biotin construct as a contrast agent molecular weight control. VEGFR2 levels are heterogeneous in different regions of C6 gliomas, whereas VEGFR2 was more homogenous or evenly distributed in RG2 gliomas. RG2 gliomas have less VEGFR2 within tumor periphery and peri-necrotic (pRG2 gliomas and corresponding contalateral brain tissues. Ex vivo VEGFR2 levels were found to be significantly higher in C6 gliomas compared to RG2 tumors (pRG2 (pRG2 gliomas. PMID:23901356

He, Ting; Smith, Nataliya; Saunders, Debra; Pittman, Benjamin P; Lerner, Megan; Lightfoot, Stanley; Silasi-Mansat, Robert; Lupu, Florea; Towner, Rheal A

2013-01-01

162

Coexistence of spinodal instability and thermal nucleation in thin-film rupture: insights from molecular levels.  

Science.gov (United States)

Despite extensive investigation using hydrodynamic models and experiments over the past decades, there remain open questions regarding the origin of the initial rupture of thin liquid films. One of the reasons that makes it difficult to identify the rupture origin is the coexistence of two dewetting mechanisms, namely, thermal nucleation and spinodal instability, as observed in many experimental studies. Using a coarse-grained model and large-scale molecular dynamics simulations, we are able to characterize the very early stage of dewetting in nanometer-thick liquid-metal films wetting a solid substrate. We observe the features characteristic of both spinodal instability and thermal nucleation in the spontaneously dewetting films and show that these two macroscopic mechanisms share a common origin at molecular levels. PMID:24730848

Nguyen, Trung Dac; Fuentes-Cabrera, Miguel; Fowlkes, Jason D; Rack, Philip D

2014-03-01

163

Early molecular-level changes in rat bladder wall tissue following spinal cord injury.  

Science.gov (United States)

Previously, we demonstrated using a rat model of spinal cord injury (SCI) that bladder wall tissue compliance significantly increased within the first 2 weeks following injury. In order to explore the potential molecular-level mechanisms of this event, the present study quantified molecules pertinent to bladder tissue remodeling and changes in mechanical properties. An initial gene array analysis followed by real-time qPCR revealed that the message levels for tropoelastin and lysyl oxidase were as high as 8-fold in SCI rats compared to normal. Furthermore, both the message and protein levels of TGF-beta1 and IGF-1, known stimulators of elastin synthesis, in SCI rat bladders were significantly higher compared to those of normal rats. Taken together, it can be speculated that functional changes of the bladder associated with SCI induce release of select growth factors, which, in turn, stimulate elastogenesis that lead to alteration of biomechanical properties of the wall tissue. PMID:16038877

Nagatomi, Jiro; DeMiguel, Fernando; Torimoto, Kazumasa; Chancellor, Michael B; Getzenberg, Robert H; Sacks, Michael S

2005-09-01

164

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 information described in this article may give better insight in the mechanisms involved and the intrinsic protein molecular structural changes occurring upon processing.

2007-01-01

165

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

166

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

167

Patterns and Processes of Molecular Evolution in Rickettsia  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Species of the genus Rickettsia are obligate intracellular parasites of the a-proteobacterial subdivision. It has been suggested that obligate intracellular bacteria have evolved from free-living bacteria with much larger genome sizes. Transitions to intracellular growth habitats are normally associated with radical genomic alterations, particularly genome rearrangements and gene losses. This thesis presents a comparative study of evolutionary processes such as gene rearrangements, deletions ...

Amiri, Haleh

2002-01-01

168

Molecular basis of processing wheat gluten toward biobased materials.  

Science.gov (United States)

The unique properties of the wheat grain reside primarily in the gluten-forming storage proteins of its endosperm. Wheat gluten's structural and functional properties have led to an expanding diversity of applications in food products. However, its viscoelastic properties and low water solubility also are very interesting features for nonfood applications. Moreover, gluten is annually renewable and perfectly biodegradable. In the processing and setting of gluten containing products, temperature plays a very important role. In this review, the structure and reactivity of gluten are discussed and the importance of sulfhydryl (SH) and disulfide (SS) groups is demonstrated. Wheat gluten aggregation upon thermosetting proceeds through direct covalent cross-linking in and between its protein groups, glutenin and gliadin. Predominant reactions include SH oxidation and SH/SS interchange reactions leading to the formation of SS cross-links. Additionally, thermal treatment of gluten can result in the formation of other than SS covalent bonds. We here review two main technological approaches to make gluten-based materials: wet processes resulting in thin films and dry processes, such as extrusion or compression molding, exploiting the thermoplastic properties of proteins under low moisture conditions and potentially resulting in very useful materials. Gluten bioplastics can also be reinforced with natural fibers, resulting in biocomposites. Although a lot of progress has been made the past decade, the current gluten materials are still outperformed by their synthetic polymer counterparts. PMID:20141101

Lagrain, Bert; Goderis, Bart; Brijs, Kristof; Delcour, Jan A

2010-03-01

169

Coarse-grained Molecular-level Analysis of Polyurea Properties and Shock-mitigation Potential  

Science.gov (United States)

Several experimental investigations reported in the open literature clearly established that polyurea (PU), an elastic copolymer, has an unusually high ability to attenuate and disperse shock waves. This behavior of PU is normally attributed to its unique nanometer-scale two-phase microstructure consisting of (high glass-transition temperature, T g) hydrogen-bonded discrete, hard domains dispersed within a (low T g) contiguous soft matrix. However, details regarding the mechanism(s) responsible for the superior shock-wave mitigation capacity of PU are still elusive. In the present study, molecular-level computational methods and tools are used to help us identify and characterize these mechanism(s). Because the shock-wave front structure and propagation involve coordinated motion of a large number of atoms and nano-second to micro-second characteristic times, these phenomena cannot be readily analyzed using all-atom molecular-level modeling and simulation techniques. To overcome this problem, all-atom PU microstructure is coarse-grained by introducing larger particles (beads), which account for the collective degrees of freedom of the constituent atoms, the associated force-field functions determined and parameterized using all-atom computational results, and the resulting coarse-grained model analyzed using conventional molecular-level computational methods and tools. The results thus obtained revealed that a combination of different deformation mechanisms (primarily shock-induced ordering and crystallization of hard domains and coordinated shuffle-like lateral motion of the soft-matrix segments) is most likely responsible for the superior ability of PU to attenuate/disperse shock waves.

Grujicic, M.; Snipes, J. S.; Ramaswami, S.; Yavari, R.; Runt, J.; Tarter, J.; Dillon, G.

2013-07-01

170

Multiscale characterization of the organization of triglycerides and phospholipids in emmental cheese: from the microscopic to the molecular level.  

Science.gov (United States)

The chemical composition and properties of lipids, both triglycerides and phospholipids, play a major role in the functional and nutritional properties of food products. In this study, the suprastructure of fat, solid fat content, and crystallographic properties of triglycerides were investigated in hard-type cheeses from the microscopic scale to the molecular level using the combination of relevant techniques. Two industrial cheeses with different oiling off properties were compared with experimental cheeses manufactured in the laboratory. Microstructural analysis performed using confocal laser scanning microscopy showed that milk processing led to the disruption of fat globules with the formation of nonglobular fat. For a similar fatty acid composition, oiling off was mainly related to the fat in dry matter content and to the suprastructure of fat in cheese. An exogenous fluorescent phospholipid permitted the localization of milk phospholipids in the cheese matrix, which mainly remain around fat inclusions after disruption of the milk fat globule membrane, and to show heterogeneities. We also showed using differential scanning calorimetry that the suprastructure of fat did not affect the solid fat content in cheese at 4 degrees C: 71.6 +/- 4.9%. The organization of triglyceride molecules in fat crystals, elucidated at a molecular level using X-ray diffraction, corresponded to the coexistence of 2 lamellar structures (2L 40.5 angstroms and 3L 54.6 angstroms) with four polymorphic forms: alpha, two beta' and beta. A schematic representation of the multiscale organization of triglycerides and phospholipids in cheese is proposed. PMID:18338865

Lopez, Christelle; Briard-Bion, Valerie; Beaucher, Eric; Ollivon, Michel

2008-04-01

171

Interface Fermi level pinning at contacts between PEDOT: PSS and molecular organic semiconductors.  

Science.gov (United States)

Photoemission studies of interfaces between molecular organic semiconductors and the conducting polymer PEDOT:PSS [mixture of PEDOT (poly-3,4-ethylenedioxy-thiophene) and PSS (polystyrenesulfonate)] demonstrate that it is impossible to control the charge injection barriers at such contacts by either a systematic change of the work function of the conducting polymer or that of the organic semiconductor. Instead, these interfaces are, in all cases, characterized by a charge transfer across the interface and a resulting Fermi level pinning. Thus interfacial charge barriers do not explain observed changes in device parameters as a function of the work function of the polymer electrode. PMID:17230589

Peisert, Heiko; Petr, Andreas; Dunsch, Lothar; Chassé, Thomas; Knupfer, Martin

2007-02-19

172

Molecular-Level Transformations of Lignin During Photo-Oxidation and Biodegradation  

Science.gov (United States)

As the second most abundant component of terrestrial plant residues, lignin plays a key role in regulating plant litter decomposition, humic substance formation, and dissolved organic matter (OM) production from terrestrial sources. Biodegradation is the primary decomposition process of lignin on land. However, photo- oxidation of lignin-derived compounds has been reported in aquatic systems and is considered to play a vital role in arid and semiarid regions. With increasing ultraviolet (UV) radiation due to ozone depletion, it is important to understand the biogeochemical fate of lignin exposed to photo-oxidation in terrestrial environments. This study examines and compares the transformation of lignin in a three-month laboratory simulation of biodegradation and photo-oxidation using molecular-level techniques. Lignin-derived monomers extracted by copper oxidation were analyzed by gas chromatography/mass spectrometry (GC/MS) from the water-soluble and insoluble OM of 13C-labeled corn leaves. Biodegradation increased the solubility of lignin monomers in comparison to the control samples, and the acid-to-aldehyde (Ad/Al) ratios increased in both the water-soluble and insoluble OM, indicating a higher degree of side-chain lignin oxidation. Photo-oxidation did not produce a significant change on the solubility or Ad/Al ratios of lignin from corn leaves. However, the ratios of trans-to-cis isomers of both cinnamyl units (p-coumaric acid and ferulic acid) increased with photo-oxidation and decreased with biodegradation in the insoluble OM. We also investigated the role of photo-oxidation in lignin transformation in soils cropped with 13C-labeled corn. Interestingly, the organic carbon content increased significantly with time in the water-soluble OM from soil/corn residues under UV radiation. An increase in the concentration of lignin monomers and dimers and the Ad/Al ratios was also observed with photo-oxidation. Iso-branched fatty acids of microbial origin remained in a similar concentration in the water-soluble OM from the UV-radiated and control soils, indicating little microbial contribution to the observed increase in water-soluble carbon. These observations suggest that photo-oxidation may increase the solubility of soil organic matter (SOM) through the oxidation of lignin-derived compounds. Mechanisms of lignin oxidation (demethylation or side-chain oxidation) and molecular size distribution changes of the water-soluble and NaOH-soluble OM during photo-oxidation and biodegradation will also be examined using solution-state nuclear magnetic resonance (NMR) spectroscopy. Collectively, our experiment demonstrates that while biodegradation predominates in the decomposition of lignin in plant litter, photo- oxidation may play an important part in destabilizing lignin-derived compounds in the soil.

Feng, X.; Hills, K.; Simpson, A. J.; Simpson, M. J.

2009-05-01

173

Woodâ??water interactions : Linking molecular level mechanisms with macroscopic performance  

DEFF Research Database (Denmark)

Predicting the performance of wood for decades ahead is important when using the material for structural purposes. The performance is closely related to the hierarchical material structure of wood and the dependent interaction with water in the structure. Accurately predicting wood performance therefore requires an understanding of material structure from molecular to macroscopic level as well as of the impact of water molecules. The objective of this work is to investigate the performance of wood in terms of mechanical response of the material and effect of water. To understand the latter, one must first know in which parts of the wood structure, water is located. If parts of the water in wood are held in capillaries in the wood structure, these water molecules interact with the material differently than those held within wood cell walls. In this study, the occurrence of capillary water in wood is investigated at high levels of relative humidity (RH), where capillary water might be present. Three different techniques are employed in overlapping RH regimes. The three techniques give similar results and show that the amount of capillary water is insignificant up to at least 99.5 % RH. Thus, for wood in equilibrium with surrounding climate in the RH range 0-99.5 %, water is only significantly present within cell walls. A structural model of a wood cell is developed in this study using Finite Element Method for predicting the mechanical performance of wood. The starting point for the model is the physical behaviour on the molecular level since water interferes with wood at this level. The elastic material properties of the wood cell wall are explained by the organisation of wood constituents and their properties. The effect of water as well as temperature is incorporated by considering the amount of hydrogen bonds between wood constituents and the stiffness of these bonds. The mechanical response of wood includes a substantial time-dependent response, which previously has been explained by sliding between wood constituents on the molecular level. In this study, this is incorporated in the model as time-dependent shearing of the material planes of the cell wall. The calculated results of the model is verified against various experimental results from literature as well as from measurements presented in this work. It is shown that the structural model is able to describe a diverse range of mechanical responses of wood cells in both elastic and time-dependent domains. Furthermore, comparison of results from experiments and model suggests that the mechanical response of wood tissue, i.e. the hierarchical level above single wood cells, is a sum of responses from both wood cells and intercellular layer, i.e. the middle lamella.

Engelund, Emil Tang

2011-01-01

174

Levels of processing and language modality specificity in working memory  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

175

Dynamics of molecular processes by NMR in liquid crystalline solvents  

Energy Technology Data Exchange (ETDEWEB)

The effect of dynamic processes on the lineshapes of NMR spectra in liquid crystalline solutions is discussed. The discussion includes dynamic /sup 1/H spectra of s-trioxane, cyclooctatetraene and bullvalene undergoing, respectively, ring inversion, bond shift and bond rearrangement. Also discussed are dynamic deuteron spectra using the examples of cyclohexane-d/sub 12/ and p-dioxane-d/sub 8/ undergoing ring inversion. Finally the formalism required to simulate dynamic NMR spectra in liquid crystalline solution is reviewed and the possible factorization of the problem by symmetry considerations is discussed.

Luz, Z. (Weizmann Inst. of Science, Rehovoth (Israel). Dept. of Isotopes)

1983-01-01

176

New tools for the study of chromosome segregation and aneuploidy at the molecular level  

Energy Technology Data Exchange (ETDEWEB)

The molecular mechanisms which allow the correct distribution of chromosomes during cell division are not yet well known. The centromere, because of its possible involvement in the attachment of sister chromatids and its participation in the formation of the kinetochore, may play an important role in these mechanisms. Trisomy 21 (down syndrome, DS) provides a good model for studying aneuploidy resulting from the dysfunction of the chromosome distribution process. A possible means of analyzing the mechanisms leading to non-disjunction (NDJ) could be to determine the origin of the supernumerary chromosome 21 and to attempt to find some structural or physical characteristics of the potentially responsible centromere. This could be performed by using molecular tools which allow each of the two parental chromosomes 21 to be distinguished. Possible markers suitable for this purpose are DNA fragments that exhibit length polymorphisms. We present here some examples of such molecular tools, and discuss ways to use them in order to study the parental origin and the meiotic stage of nondisjunction, and we propose an hypothesis suggesting a possible cause of nondisjunction in human chromosomes.

Charlieu, J.P.; Marcais, B.; Laurent, A.M.; Roizes, G. [Institut de Biologie, Montpellier (France)

1993-12-31

177

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

178

Renormalization of Molecular Quasiparticle Levels at Metal-Molecule Interfaces: Trends across Binding Regimes  

DEFF Research Database (Denmark)

When an electron or a hole is added into an orbital of an adsorbed molecule the substrate electrons will rearrange in order to screen the added charge. This polarization effect reduces the electron addition and removal energies of the adsorbed molecule relative to those of the free molecule. Using a microscopic model of the metal-molecule interface, we illustrate the basic features of this renormalization mechanism through systematic GW, Hartree-Fock, and Kohn-Sham calculations for the molecular energy levels as function of the model parameters. We identify two different polarization mechanisms: (i) polarization of the metal (image charge formation) and (ii) polarization of the molecule via charge transfer across the interface. The importance of (i) and (ii) is found to increase with the metal density of states at the Fermi level and metal-molecule coupling strength, respectively.

Thygesen, Kristian Sommer; Rubio, Angel

2009-01-01

179

Effects of stimulus type and level repetition on content-level binding in global/local processing  

Directory of Open Access Journals (Sweden)

Full Text Available 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 factors on the binding process, namely stimulus type (filled or outlined hierarchical letters, stimulus-type repetition, and target-level repetition. The results show that content-level binding was improved for outlined stimuli and after target-level repetition, whereas stimulus-type repetition had no effect. The data suggest that hierarchical stimuli are mentally represented by abstract level categories and that content is linked to these categories by means of level-specific and identity-specific spatial-frequency information.

RonaldHübner

2011-06-01

180

Mean level signal crossing rate for an arbitrary stochastic process  

DEFF Research Database (Denmark)

The issue of the mean signal level crossing rate for various probability density functions with primary relevance for optics is discussed based on a new analytical method. This method relies on a unique transformation that transforms the probability distribution under investigation into a normal probability distribution, for which the distribution of mean level crossings is known. In general, the analytical results for the mean level crossing rate are supported and confirmed by numerical simulations. In particular, we illustrate the present method by presenting analytic expressions for the mean level crossing rate for various probability distributions, including ones that previously were unavailable, such as the uniform, the so-called gamma-gamma, and the Riceâ??Nakagami distribution. However, in a limited number of cases the present results differ somewhat from the result reported in the literature. At present, this discrepancy remains unexplained and is laid open for future discussion.

Hanson, Steen Grüner

2010-01-01

 
 
 
 
181

Dynamics of multiphoton processes in two-level systems  

International Nuclear Information System (INIS)

The generalized kinetic equation for two-photon processses in the macroscopic two-level system is obtained. The possibility of emission and adsorption is examined. The conditions of superradiant generation are pointed out

1985-03-01

182

Dynamics of multiphoton processes in two-level systems  

Energy Technology Data Exchange (ETDEWEB)

The generalized kinetic equation for two-photon processses in the macroscopic two-level system is obtained. The possibility of emission and adsorption is examined. The conditions of superradiant generation are pointed out.

Bogolyubov, N.N.; Fam Le Kien; Shumovskij, A.S.

1985-03-01

183

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

184

Supramolecular and heterosupramolecar chemistry in controlled release and molecular recognition processes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

La presente tesis doctoral titulada ¿Supramolecular and heterosupramolecular chemistry in controlled release and molecular recognition processes¿ está centrada en los dos aspectos principales de la química supramolecular que han experimentado un gran auge en los últimos años: el reconocimiento molecular y los procesos de liberación controlada. En particular la primera parte de la tesis se focaliza en el diseño y síntesis de moléculas orgánicas que pueden ser emp...

Agostini, Alessandro

2013-01-01

185

Molecular photoionization processes of astrophysical and aeronomical interest  

Science.gov (United States)

An account is given of aspects of photoionization processes in molecules, with particular reference to recent theoretical and experimental studies of partial cross sections for production of specific final electronic states and of parent and fragment ions. Such cross sections help provide a basis for specifying the state of excitation of the ionized medium, are useful for estimating the kinetic energy distributions of photoejected electrons and fragment ions, provide parent-and fragment-ion yields, and clarify the possible origins of neutral fragments in highly excited rovibronic states. A descriptive account is given of photoionization phenomena, including tabulation of valence- and inner-shell potentials for some molecules of astrophysical and aeronomical interest. Cross sectional expressions are given. Various approximations currently employed in computational studies are described briefly, threshold laws and high-energy limits are indicated, and distinction is drawn between resonant and direct photoionization phenomena. Recent experimental and theoretical studies of partial photoionization cross sections in selected compounds of astrophysical and aeronomical relevance are described and discussed.

Langhoff, P. W.

1985-01-01

186

Molecular Insights into Poly(ADP-ribose Recognition and Processing  

Directory of Open Access Journals (Sweden)

Full Text Available Poly(ADP-ribosylation is a post-translational protein modification involved in the regulation of important cellular functions including DNA repair, transcription, mitosis and apoptosis. The amount of poly(ADP-ribosylation (PAR in cells reflects the balance of synthesis, mediated by the PARP protein family, and degradation, which is catalyzed by a glycohydrolase, PARG. Many of the proteins mediating PAR metabolism possess specialised high affinity PAR-binding modules that allow the efficient sensing or processing of the PAR signal. The identification of four such PAR-binding modules and the characterization of a number of proteins utilising these elements during the last decade has provided important insights into how PAR regulates different cellular activities. The macrodomain represents a unique PAR-binding module which is, in some instances, known to possess enzymatic activity on ADP-ribose derivatives (in addition to PAR-binding. The most recently discovered example for this is the PARG protein, and several available PARG structures have provided an understanding into how the PARG macrodomain evolved into a major enzyme that maintains PAR homeostasis in living cells.

Ivan Ahel

2012-12-01

187

Level Crossing Probabilities of the Ornstein – Uhlenbeck Process  

Directory of Open Access Journals (Sweden)

Full Text Available The Ornstein Uhlenbeck process is a Gaussian process t X with independentincrements and autocorrelation ( 2st t sE X X e?+ = . First the Laplace transform of theprobability density P(X x X p t = = 0 is computed. Using this, the Laplace transformof t X first time reaching a given value x is derived. It is proved that these results agreewith the special case derived earlier by Bellman and Harris (Pacific J. Math. 1, 1951.

József Dénes

2006-04-01

188

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.

de Cerqueira, Caio Cesar Silva; Hunemeier, Tabita; Gomez-Valdes, Jorge; Ramallo, Virginia; Volasko-Krause, Carla Daiana; Barbosa, Ana Angelica Leal; Vargas-Pinilla, Pedro; Dornelles, Rodrigo Ciconet; Longo, Danae; Rothhammer, Francisco; Bedoya, Gabriel; Canizales-Quinteros, Samuel; Acuna-Alonzo, Victor; Gallo, Carla; Poletti, Giovanni; Gonzalez-Jose, Rolando; Salzano, Francisco Mauro; Callegari-Jacques, Sidia Maria; Schuler-Faccini, Lavinia; Ruiz-Linares, Andres; Catira Bortolini, Maria

2014-01-01

189

Optimal values of rovibronic energy levels for triplet electronic states of molecular deuterium  

Energy Technology Data Exchange (ETDEWEB)

An optimal set of 1050 rovibronic energy levels for 35 triplet electronic states of D{sub 2} has been obtained by means of a statistical analysis of all available wavenumbers of triplet-triplet rovibronic transitions studied in emission, absorption, laser and anticrossing spectroscopic experiments of various authors. We used a new method of analysis (Lavrov and Ryazanov 2005 JETP Lett. 81 371-4), which does not need any a priori assumptions concerning the molecular structure, being based on only two fundamental principles: Rydberg-Ritz and maximum likelihood. The method provides the opportunity to obtain the root-mean-square estimates for uncertainties of the experimental wavenumbers independent from those presented in the original papers. A total of 234 from 3822 published wavenumber values were found to be spurious, while the remaining set of the data may be divided into 20 subsets (samples) of uniformly precise data having close to normal distributions of random errors within the samples. New experimental wavenumber values of 125 questionable lines were obtained in the present work. Optimal values of the rovibronic levels were obtained from the experimental data set consisting of 3713 wavenumber values (3588 old and 125 new). The unknown shift between levels of ortho- and para-deuterium was found by least-squares analysis of the a{sup 3}{sigma}{sup +}{sub g}, v = 0, N = 0 to 18 rovibronic levels with odd and even values of N. All the energy levels were obtained relative to the lowest vibro-rotational level (v = 0, N = 0) of the a{sup 3}{sigma}{sup +}{sub g} electronic state, and presented in tabular form together with the standard deviations of the empirical determination. New energy-level values differ significantly from those available in the literature.

Lavrov, B P; Umrikhin, I S [Faculty of Physics, St Petersburg State University, St Petersburg 198504 (Russian Federation)], E-mail: lavrov@pobox.spbu.ru

2008-05-28

190

Optimal values of rovibronic energy levels for triplet electronic states of molecular deuterium  

International Nuclear Information System (INIS)

An optimal set of 1050 rovibronic energy levels for 35 triplet electronic states of D2 has been obtained by means of a statistical analysis of all available wavenumbers of triplet-triplet rovibronic transitions studied in emission, absorption, laser and anticrossing spectroscopic experiments of various authors. We used a new method of analysis (Lavrov and Ryazanov 2005 JETP Lett. 81 371-4), which does not need any a priori assumptions concerning the molecular structure, being based on only two fundamental principles: Rydberg-Ritz and maximum likelihood. The method provides the opportunity to obtain the root-mean-square estimates for uncertainties of the experimental wavenumbers independent from those presented in the original papers. A total of 234 from 3822 published wavenumber values were found to be spurious, while the remaining set of the data may be divided into 20 subsets (samples) of uniformly precise data having close to normal distributions of random errors within the samples. New experimental wavenumber values of 125 questionable lines were obtained in the present work. Optimal values of the rovibronic levels were obtained from the experimental data set consisting of 3713 wavenumber values (3588 old and 125 new). The unknown shift between levels of ortho- and para-deuterium was found by least-squares analysis of the a3?+g, v = 0, N = 0 to 18 rovibronic levels with odd and even values of N. All the energy levels were obtained relative to the lowest vibro-rotational level (v = 0, N = 0) of the a3?+g electronic state, and presented in tabular form together with the standard deviations of the empirical determination. New energy-level values differ significantly from those available in the literature

2008-05-28

191

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 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)

2001-10-02

192

Impact of conversion level of hydrocarbon transformation in fluid catalytic cracking processes studied by combined chromatography and mass spectrometry  

Energy Technology Data Exchange (ETDEWEB)

A fundamental understanding of the impact of feedstock properties on catalyst performance and on the molecular transformation in the fluid catalytic cracking (FCC) process has been of great interest to both petroleum and catalyst manufacturers. For the latter, this understanding provides an important guide toward the design and improvement of catalyst structure and formulation to achieve desired product performance. The level of conversion (conversion wt%) is an important measurement of optimized catalyst performance. Combined chromatography separation and mass spectrometry provides an effective tool to study the impact of conversion level on hydrocarbon transformation and to identify the nature of hard-to-crack molecules and their contributions to the bottoms yield.

Qian, K.; Harding, R.H.; Zhao, Xinjin [W.R. Grace Co.-Conn., Columbia, MD (United States)

1995-12-31

193

Molecular Studies on the Ecology of Listeria monocytogenes in the Smoked Fish Processing Industry  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have applied molecular approaches, including PCR-based detection strategies and DNA fingerprinting methods, to study the ecology of Listeria monocytogenes in food processing environments. A total of 531 samples, including raw fish, fish during the cold-smoking process, finished product, and environmental samples, were collected from three smoked fish processing facilities during five visits to each facility. A total of 95 (17.9%) of the samples tested positive for L. monocytogenes using a ...

Norton, Dawn M.; Mccamey, Meghan A.; Gall, Kenneth L.; Scarlett, Janet M.; Boor, Kathryn J.; Wiedmann, Martin

2001-01-01

194

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

195

Dissecting Aerosol Indirect Effects on the Process Level  

Science.gov (United States)

There are multiple processes leading from aerosol emissions to indirect effects (TOA flux changes). For the first indirect effect (IE), a rough sketch looks like emissions -> dry aerosols -> activations into droplets -> cloud albedo -> radiative flux changes. It is even more complicated for the second IE. The guiding principle of the framework that I advocate here is to examine one process at a time. One can compare its representations across models, while checking them against observations and theories. As a proof of concept, I will examine how cloud albedo would vary with droplet number (or the so-called cloud susceptibility).

Ming, Y.

2013-12-01

196

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)

2007-10-05

197

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

Energy Technology Data Exchange (ETDEWEB)

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)

Shinzato, Rodrigo; Otaguro, Harumi; Lima, Luis F.C.P.; Parra, Duclerc F.; Lugao, Ademar B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente], E-mail: rodrigo.shinzato@gmail.com, E-mail: ablugao@ipen.br; Artel, Beatriz W.H. [Empresa Brasileira de Radiacao Ltda. (EMBRARAD), Cotia, SP (Brazil)

2007-07-01

198

Correlating molecular spectroscopy and molecular chemometrics to explore carbohydrate functional groups and utilization of coproducts from biofuel and biobrewing processing.  

Science.gov (United States)

Dried distillers grains with solubles (DDGS) was coproducts from bioethanol and biobrewing industry. It was an excellent resource of protein and energy feedstuff in China. Conventional studies often focus on traditional nutritional profiles. To data, there is little research on molecular structure-nutrition interaction of carbohydrate in coproducts. In this study, five kinds of corn-grain based DDGS and two kinds of barley-grain based DDGS were collected from different manufactures in the north of China. They were coded as "1, 2, 3, 4, 5, 6, and 7", respectively. The primary purposes of this project were to investigate the molecular structure-nutrition interaction of carbohydrate in coproducts, in terms of (1) carbohydrate-related chemical composition and nutrient profiles, (2) predicted values for energy in coproducts for animal, and (3) in situ digestion of dry matter. The result showed that acid detergent fiber content in corn DDGS and barley DDGS had negative correlation with structural carbohydrate peak area, cellulose compounds, and carbohydrate component peaks (first, second, and total peak area), which were measured with molecular spectroscopy. The correlation between carbohydrate peak area (second and total) and digestible fiber (tdNDF) were negative. There were no correlation between carbohydrate spectral intensities and energy values, carbohydrate subfractions partitioned by CNCPS system, and in situ rumen degradation. The results indicate that carbohydrate spectral profiles (functional groups) are associated with the carbohydrate nutritive values in coproducts from biofuel and biobrewing processing. PMID:24738876

Chen, Limei; Zhang, Xuewei; Yu, Peiqiang

2014-06-01

199

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

200

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

 
 
 
 
201

Disorganisation in the transition process : firm level evidence from Ukraine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Most post-communist economies are characterized by an initial collapse in aggregate output. Blanchard and Kremer (1997) and Roland and Verdier (1997) have recently modelled supply side distortions, disorganization in the links of production, that can lead to a short-term output contraction after market liberalisation and a recovery thereafter. This paper is the first to illustrate and test the effects of disorganization in the transition process by using a unique data set of 300 U...

Konings, Jozef; Walsh, Patrick P.

1998-01-01

202

Two-center interference effects on the electron capture process by alpha particles from molecular hydrogens  

Energy Technology Data Exchange (ETDEWEB)

The single-electron capture process in the collision of fast alpha particles with hydrogen molecules is treated using the first-order Born approximation with correct boundary conditions. The results are obtained by considering both the inter-nuclear and nuclear-electronic interactions and by employing a Hartree-Fock molecular wave function. Double differential cross sections are evaluated for the electron capture from a molecular target with a fixed orientation. In the fixed-nuclei approximation, the differential cross sections are calculated for an equally-weighted averaging over all molecular orientations. The interference patterns, due to the scattering from two atomic centers, are apparent in different forms both in the double differential cross sections and in the cross sections as a function of the angle between the molecular axis and the incident direction. Integrated cross sections are calculated and compared with other theoretical and experimental results.

Ghanbari-Adivi, E. [Physics Department and Isfahan Quantum-Optics Group (IQOG), University of Isfahan, Hezar Jerib Street, Isfahan 8174673441 (Iran, Islamic Republic of)], E-mail: ghanbari@phys.ui.ac.ir

2009-10-01

203

Short-term molecular-level effects of silver nanoparticle exposure on the earthworm, Eisenia fetida  

International Nuclear Information System (INIS)

Short-term changes in levels of expression of nine stress response genes and oxidative damage of proteins were examined in Eisenia fetida exposed to polyvinylpyrrolidone (PVP) coated Ag nanoparticles (Ag-NP) and AgNO3 in natural soils. The responses varied significantly among days with the highest number of significant changes occurring on day three. Similarity in gene expression patterns between Ag-NPs and AgNO3 and significant relationships of expression of CAT and HSP70 with Ag soil concentration suggest similarity in toxicity mechanisms of Ag ions and NPs. Significant increases in the levels of protein carbonyls on day three of the exposure to both ions and Ag-NPs indicate that both treatments induced oxidative stress. Our results suggest that Ag ions drive short term toxicity of Ag-NPs in E. fetida. However, given that 3 and Ag nanoparticles were similar. ? Expression of CAT and HSP70 were correlated with Ag soil concentration. ? Increase in protein carbonyls by ions and nanoparticles on day three. ? The results suggest that short-term toxicity is driven by Ag ions. - Similarity in molecular-level responses between silver nanoparticles (Ag-NPs) and ions suggests that ions are primarily responsible for short-term toxicity of Ag-NPs to Eisenia fetida.

2012-12-01

204

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

205

Optimal values of rovibronic energy levels for triplet electronic states of molecular deuterium  

CERN Document Server

Optimal set of 1050 rovibronic energy levels for 35 triplet electronic states of $D_2$ has been obtained by means of a statistical analysis of all available wavenumbers of triplet-triplet rovibronic transitions studied in emission, absorption, laser and anticrossing spectroscopic experiments of various authors. We used a new method of the analysis (Lavrov, Ryazanov, JETP Letters, 2005), which does not need any \\it a priory \\rm assumptions concerning the molecular structure being based on only two fundamental principles: Rydberg-Ritz and maximum likelihood. The method provides the opportunity to obtain the RMS estimates for uncertainties of the experimental wavenumbers independent from those presented in original papers. 234 from 3822 published wavenumber values were found to be spurious, while the remaining set of the data may be divided into 20 subsets (samples) of uniformly precise data having close to normal distributions of random errors within the samples. New experimental wavenumber values of 125 questi...

Lavrov, B P

2008-01-01

206

Molecular Characterization of Banana (AA Diploids with Contrasting Levels of Black and Yellow Sigatoka Resistance  

Directory of Open Access Journals (Sweden)

Full Text Available Most banana cultivars are susceptible to many diseases, whereas Sigatoka leads to greatest yield losses. One of the strategies to overcome this disease is thorough banana genetic breeding which consists in the obtainment of improved (AA diploids which are then crossed with triploids obtaining (AAAB tetraploid disease resistant bananas also presenting other important agronomic characteristics. The prior knowledge of the genetic diversity of (AA diploids, is therefore considered indispensable in order to direct the crosses being made. The objective of the present work was to analyze the genetic diversity of 20 (AA banana diploids with contrasting levels of reaction to yellow and black Sigatoka caused by Mycosphaerella musicola and M. fijensis, respectively, using molecular markers. From the dendrogram data it is shown that a great number of experimental hybrids can be obtained from the combination of genetically different diploids, therefore making the banana genetic breeding program more efficient regarding its objectives.

Claudia F. Ferreira

2004-01-01

207

Highly consistent patterns for inherited human diseases at the molecular level.  

Science.gov (United States)

Over 1600 mammalian genes are known to cause an inherited disorder, when subjected to one or more mutations. These disease genes represent a unique resource for the identification and quantification of relationships between phenotypic attributes of a disease and the molecular features of the associated disease genes, including their ascribed annotated functional classes and expression patterns. Such analyses can provide a more global perspective and a deeper understanding of the probable causes underlying human hereditary diseases. In this perspective and critical view of disease genomics, we present a comparative analysis of genes reported to cause inherited diseases in humans in terms of their causative effects on physiology, their genetics and inheritance modes, the functional processes they are involved in and their expression profiles across a wide spectrum of tissues. Our analysis reveals that there are more extensive correlations between these attributes of genetic disease genes than previously appreciated. For instance, the functional pattern of genes causing dominant and recessive diseases is markedly different. Also, the function of the genes and their expression correlate with the type of disease they cause when mutated. The results further indicate that a comparative genomics approach for the analysis of genes linked to human genetic diseases will facilitate the elucidation of the underlying molecular and cellular mechanisms. PMID:16287936

López-Bigas, Núria; Blencowe, Benjamin J; Ouzounis, Christos A

2006-02-01

208

Investigating Students' Ability to Transfer Ideas Learned from Molecular Animations of the Dissolution Process  

Science.gov (United States)

Animations of the particulate level of matter are widely available for use in chemistry classes and are often the primary means of representing molecular behavior. These animations may also be viewed by individual students using textbook Web sites, although without reinforcement or feedback. It is not known to what extent the material in these…

Kelly, Resa M.; Jones, Loretta L.

2008-01-01

209

High level radioactive waste vitrification process equipment component testing  

Energy Technology Data Exchange (ETDEWEB)

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.

Siemens, D.H.; Heath, W.O.; Larson, D.E.; Craig, S.N.; Berger, D.N.; Goles, R.W.

1985-04-01

210

MIPAS Level 1B algorithms overview: operational processing and characterization  

Directory of Open Access Journals (Sweden)

Full Text Available This paper gives an overview of the MIPAS Level 1B (L1B processor whose main objective is to calibrate atmospheric measurements radiometrically, spectrally and geo-located. It presents also the results of instrument characterization done on ground and during the first years in-flight. An accurate calibration is mandatory for high quality atmospheric retrievals. MIPAS has shown very good performance and stability. The noise equivalent spectral radiance ranges from 3 to 50 nW/(cm2 sr cm?1 and is well within the requirements over nearly the whole spetral range. The systematic radiometric error is estimated to be within 1 or 2% in most situations.

A. Kleinert

2007-01-01

211

Node Level Power system State Estimation – A Parallel Processing Technique  

Directory of Open Access Journals (Sweden)

Full Text Available Real time State Estimation is very important part of any SCADA based Energy Management System (EMS. In the SE, the measurement equations for bus voltage magnitude, real and reactive power, are all nonlinear and the solution must be based on iterative methods like Newton-Raphson method. For real time application, SE should able to execute repetitively at short intervals. However, the Power System is highly distributed in nature and includes large number of connected buses. The various measurements taken at each bus are then transferred to the centre station where the SE computations are done using the system parameter, measured data and network equations. one can make out two very important points at this stage. In-order to improve the performance of SE, in practice, the large power system is split in to sub-networks and each sub-network is managed by the local control station in coordination with the Centre station – “Two level SE” [1][2][3][8][9][12]. Even though it reduces the computational time, still it is not suitable for real time applications. To overcome the above difficulty and obtain a computationally inexpensive real time update of the state vector, tracking state estimation algorithms have been proposed and discussed in various research papers available in the literature [4][6][13]. Many techniques such as AI [16][17], Multi-level SE [11][20] and a few other [5][10][14][15][18][19] are used in SE. The concept presented in this paper opens up an whole new approach, which can bring revolution in power system state monitoring and control.

H. Nagaraja Udupa

2013-07-01

212

Belowground Carbon Cycling Processes at the Molecular Scale: An EMSL Science Theme Advisory Panel Workshop  

Energy Technology Data Exchange (ETDEWEB)

As part of the Belowground Carbon Cycling Processes at the Molecular Scale workshop, an EMSL Science Theme Advisory Panel meeting held in February 2013, attendees discussed critical biogeochemical processes that regulate carbon cycling in soil. The meeting attendees determined that as a national scientific user facility, EMSL can provide the tools and expertise needed to elucidate the molecular foundation that underlies mechanistic descriptions of biogeochemical processes that control carbon allocation and fluxes at the terrestrial/atmospheric interface in landscape and regional climate models. Consequently, the workshop's goal was to identify the science gaps that hinder either development of mechanistic description of critical processes or their accurate representation in climate models. In part, this report offers recommendations for future EMSL activities in this research area. The workshop was co-chaired by Dr. Nancy Hess (EMSL) and Dr. Gordon Brown (Stanford University).

Hess, Nancy J.; Brown, Gordon E.; Plata, Charity

2014-02-21

213

Molecular dynamics simulation study of the ? - and ? -relaxation processes in a realistic model polymer  

Science.gov (United States)

Molecular dynamics simulations of a melt of freely rotating chains of 1,4-polybutadiene (FRC-PBD) have been performed over a wide range of temperature. Removal of the dihedral barriers in FRC-PBD allows for complete resolution of the Johari-Goldstein ? process from the primary ? process in the simulation time window. We find that relaxation in the ? regime occurs as the result of large-angle excursions of all backbone dihedrals. While during the ? process each dihedral visits all available states, the complete relaxation of torsional autocorrelation function ( ? process) occurs only when the polymer matrix shows significant motion and each dihedral populates all states with equilibrium probability.

Bedrov, Dmitry; Smith, Grant D.

2005-05-01

214

Synthesis of carbon molecular sieves from chars produced in a coal retorting process  

Energy Technology Data Exchange (ETDEWEB)

Chars produced in a coal retorting process are good precursors for the production of carbon molecular sieve (CMS), a new type of activated carbon, used for air separation. The air separating performance of the CMS derived from these chars and its pore characteristics depend on the experimental conditions and on the properties of the char precursor. 7 refs., 3 figs., 1 tab.

Qiu, J.; Guo, S. [Dalian University of Technology, Dalian (China). Institute of Coal Chemical Engineering

1995-12-31

215

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 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.

2012-04-18

216

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

Science.gov (United States)

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 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.

Takada, K.; Tomioka, A.

2012-04-01

217

Complete reconstruction of an enzyme-inhibitor binding process by molecular dynamics simulations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The understanding of protein–ligand binding is of critical importance for biomedical research, yet the process itself has been very difficult to study because of its intrinsically dynamic character. Here, we have been able to quantitatively reconstruct the complete binding process of the enzyme-inhibitor complex trypsin-benzamidine by performing 495 molecular dynamics simulations of free ligand binding of 100 ns each, 187 of which produced binding events with an rmsd less than 2 ? compa...

2011-01-01

218

Process Based Large Scale Molecular Dynamic Simulation of a Fuel Cell Catalyst Layer  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, a large scale molecular dynamic method for reconstruction of the catalyst layers (CLs) in proton exchange membrane fuel cells is developed as a systematic technique to provide an insight into the self-organized phenomena and the microscopic structure. The proposed Coarse-Grained (CG) method is developed and applied to the step formation process, which follows the preparation of the catalyst-coated membranes (CCMs). The fabrication process is mimicked and evaluated in details wi...

Xiao, Yu; Yuan, Jinliang; Sunde?n, Bengt

2012-01-01

219

Real-time investigation of nucleic acids phosphorylation process using molecular beacons  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Phosphorylation of nucleic acids is an indispensable process to repair strand interruption of nucleic acids. We have studied the process of phosphorylation using molecular beacon (MB) DNA probes in real-time and with high selectivity. The MB employed in this method is devised to sense the product of a ‘phosphorylation–ligation’ coupled enzyme reaction. Compared with the current assays, this novel method is convenient, fast, selective, highly sensitive and capable of real-time monitoring...

2005-01-01

220

MULTI LEVEL SEMANTIC EXTRACTION FOR CRICKET VIDEO BY TEXT PROCESSING  

Directory of Open Access Journals (Sweden)

Full Text Available Semantic video analysis, indexing and retrieval are necessary for effective utilization of video repositories. The semantics can be extracted from the semantic carriers such as voice and video text. Super imposed text is the proper source to extract semantics of the video which will increase the efficiency of retrieval system. This paper proposes a semiautomatic method to generate annotation for cricket videos and an automated tool- DLER, to extract the semantics of cricket video. The DLER tool provides a fast and robust approach for text Detection, Localization, Extraction, and Reorganization in video frames, which is flexible and customer friendly. The DLER integrates all the pre-processing steps and the OCR steps in to a single unit. The annotator can pick the ROI, increase or decrease the threshold, contrast, brightness or inverse the image based on the typeof the broadcasted video. The tool has been implemented and tested with cricket video and the results of the experiments are promising. Finally conclusion and future work has been discussed.

Dr. SUNITHA ABBURU

2010-10-01

 
 
 
 
221

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

222

Tapping natural variation at functional level reveals allele specific molecular characteristics of potato invertase Pain-1.  

Science.gov (United States)

Biochemical, molecular and genetic studies emphasize the role of the potato vacuolar invertase Pain-1 in the accumulation of reducing sugars in potato tubers upon cold storage, and thereby its influence on the quality of potato chips and French fries. Previous studies showed that natural Pain-1 cDNA alleles were associated with better chip quality and higher tuber starch content. In this study, we focused on the functional characterization of these alleles. A genotype-dependent transient increase of total Pain-1 transcript levels in cold-stored tubers of six different genotypes as well as allele-specific expression patterns were detected. 3D modelling revealed putative structural differences between allelic Pain-1 proteins at the molecule's surface and at the substrate binding site. Furthermore, the yeast SUC2 mutant was complemented with Pain-1 cDNA alleles and enzymatic parameters of the heterologous expressed proteins were measured at 30 and 4?°C. Significant differences between the alleles were detected. The observed functional differences between Pain-1 alleles did not permit final conclusions on the mechanism of their association with tuber quality traits. Our results show that natural allelic variation at the functional level is present in potato, and that the heterozygous genetic background influences the manifestation of this variation. PMID:22621197

Draffehn, Astrid M; Durek, Pawel; Nunes-Nesi, Adriano; Stich, Benjamin; Fernie, Alisdair R; Gebhardt, Christiane

2012-12-01

223

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

224

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

225

A simplified molecular method for distinguishing among species and ploidy levels in European water frogs (Pelophylax).  

Science.gov (United States)

Western Palearctic water frogs in the genus Pelophylax are a set of morphologically similar anuran species that form hybridogenetic complexes. Fully reliable identification of species and especially of hybrid ploidy depends on karyological and molecular methods. In central Europe, native water frog populations consist of the Pelophylax esculentus complex, that is, P. lessonae (LL), P. ridibundus (RR) and the hybrid form P. esculentus that can have different karyotypes (RL, LLR and RRL). We developed existing molecular methods further and propose a simple PCR method based on size-differences in the length of the serum albumin intron-1 and the RanaCR1, a non-LTR retrotransposon of the chicken repeat (CR) family. This PCR yields taxon-specific banding patterns that can easily be screened by standard agarose gel electrophoresis and correctly identify species in all of the 160 samples that had been identified to karyotype with other methods. To distinguish ploidy levels in LR, LLR and RRL specimens, we used the ratio of the peak heights of the larger (ridibundus specific) to the smaller (lessonae specific) bands of fluorescently labelled PCR products resolved on a capillary DNA sequencer and obtained a correct assignment of the karyotype in 93% of cases. Our new method will cut down time and expenses drastically for a reliable identification of water frogs of the P. esculentus complex and potentially for identification of other hybridogenetic complexes and/or taxa, and it even serves as a good indicator of the ploidy status of hybrid individuals. PMID:22716763

Hauswaldt, J Susanne; Höer, Manuela; Ogielska, Maria; Christiansen, Ditte G; Dziewulska-Szwajkowska, Daria; Czernicka, El?bieta; Vences, Miguel

2012-09-01

226

The challenges for molecular nutrition research 3: comparative nutrigenomics research as a basis for entering the systems level.  

Science.gov (United States)

Human nutrition and metabolism may serve as the paradigm for the complex interplay of the genome with its environment. The concept of nutrigenomics now enables science with new tools and comprehensive analytical techniques to investigate this interaction at all levels of the complexity of the organism. Moreover, nutrigenomics seeks to better define the homeostatic control mechanisms, identify the de-regulation in the early phases of diet-related diseases, and attempts to assess to what extent an individual's sensitizing genotype contributes to the overall health or disease state. In a comparative approach nutrigenomics uses biological systems of increasing complexity from yeast to mammalian models to define the general rules of metabolic and genetic mechanisms in adaptations to the nutritional environment. Powerful information technology, bioinformatics and knowledge management tools as well as new mathematical and computational approaches now make it possible to study these molecular mechanisms at the cellular, organ and whole organism level and take it on to modeling the processes in a "systems biology" approach. This review summarizes some of the concepts of a comparative approach to nutrigenomics research, identifies current lacks and proposes a concerted scientific effort to create the basis for nutritional systems biology. PMID:18830658

Daniel, Hannelore; Drevon, Christian A; Klein, Ulla I; Kleemann, Robert; van Ommen, Ben

2008-12-01

227

Smallest artificial molecular neural-net for collective and emergent information processing  

Science.gov (United States)

While exploring the random diffusion of 2 bit molecular switches (we define as molecular neuron) on an atomic flat Au (111) substrate, we have found that at least four molecules are required to construct a functional neural net. Surface electron density wave enables communication of one to many molecules at a time-a prerequisite for the parallel processing. Here we have shown that in a neural net of several molecules, some of them could dynamically store information as memory and consistently replicate the fundamental relationship that is found only in a collective and emergent computing system like our brain.

Bandyopadhyay, Anirban; Sahu, Satyajit; Fujita, Daisuke

2009-09-01

228

Investigating the Formation of Helical States in the Process of Homopolymer Collapse using Molecular Dynamics Simulations  

Directory of Open Access Journals (Sweden)

Full Text Available The molecular process of homopolymer collapse was numerically modelled through isothermal molecular dynamics simulations. The initial polymer chains were constructed, using random walks in continuum space. A simple harmonic potential was used in order to represent short range interactions between monomers. Measurement of the conformational properties of the polymer during the collapse was performed, while different collapse pathways were also observed. Specifically the spontaneous collapse of the polymer to helical states occurred at low temperatures. It may be concluded that the numerical results are in perfect agreement with those of Langevin dynamics simulations conducted in a previous study.

M. Bouarkat

2010-01-01

229

Molecular Characterization of Soybean Mosaic Virus NIa Protein and its Processing Event in Bacterial Expression  

Directory of Open Access Journals (Sweden)

Full Text Available Soybean mosaic virus (SMV-CN18 is an Rsv resistance-breaking (RB isolate to overcome soybean resistance genes Rsv1, Rsv3 and Rsv4. The aim of this study was to characterize nuclear inclusion protein a (NIa protein of RB isolate at the molecular level and demonstrate its processing into genome-linked protein (VPg and NIa-Pro domains in Esherichia coli containing a bacterial expression pET vector inserted with NIa gene. The full-length of NIa gene was synthesized by reverse transcription-polymerase chain reaction (RT-PCR and its 1298 nucleotides (nt and 432 amino acids (aa were deduced. The nt and aa sequences of NIa gene of SMV-CN18 shared high identities with the corresponding sequences of the NIa gene of the known SMV isolates, suggesting that the NIa is a highly conserved protein. The NIa-Pro domain contains a highly conserved structural motif for proteolysis, while the VPg domain contains a nuclear localization signal (NLS, a putative NTP-binding site and cellular factor-binding sites. The phylogenetic tree revealed that less divergence of NIa protein exists among twelve SMV isolates, which can be supported by a low bootstrap value between clades. In addition, the full-length of NIa gene, amplified by RT-PCR, was ligated into pET-28b E. coli expression vector with an N-terminal His6-tag. Optimal conditions for expression were at 1mM treatment of IPTG at 25°C for 5 hr. The released protein from bacterial lysates remained soluble and proved the processing form of the NIa polyprotein. E. coli expression system shows the processed product of 29 kDa VPg in SDS-PAGE confirmed by western blot analysis in both crude extracts and purified elution products, using Ni2+-NTA resin. The present study indicates that the N-terminal region of NIa which is processed and expressed in bacteria.

Bong K. Choi

2006-01-01

230

Real Time Implementation of Wiener Model PI (WMPI) Controller in a Conical Tank Liquid Level Process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Level control is very important for the successful operation of most chemical and biochemical industries since it is through the proper control of flows and levels that the desired production rates and inventories can be achieved. The aim of this study was the development and real time implementation of a Wiener Model based PI Controller (WMPIC) for a conical tank level process. The conical tank level process exhibits severe static non-linear behavior and dynamic characteristics. Here, a WMPI...

2007-01-01

231

Optimizing the process of mechanical dehydration of high moor peat with a low level of decomposition  

Energy Technology Data Exchange (ETDEWEB)

Using extremum methods of experimental design, a mathematical model is derived for the mechanical dehydration process of frozen peat, and the optimum parameters of the pressing process of high moore peat with a low level of decomposition are established.

Sherstnev, V.I.; Aleksandrov, B.M.; Kungurov, E.N.; Teterin, A.G.

1980-01-01

232

A methodology to assess the maturity level of brewery business processes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this project is to develop a procedure to assess the maturity level of the brewery business processes to be able to determine the required level of process automation & IT for a brewery.This procedure is made up by several tailored questionnaires that have been based on the Process and Enterprise Maturity Model management assessment tool. This tool is described in the article called The Process Audit written by Michael Hammer and published by Harvard Business Review in 2007...

Armenda?riz, Mikel

2010-01-01

233

PIM 2003: The 3-rd Conference on Isotopic and Molecular Processes. Abstracts  

International Nuclear Information System (INIS)

The proceedings of the 3-rd Conference on Isotopic and Molecular Processes held on September 25 - 27, 2003 in Cluj - Napoca, Romania, contains contributions presented as plenary lectures, oral presentations and posters in four sections, namely: 1. Isotopic separation, labelled compounds and applications; 2. Advanced molecular systems; 3. Mass spectrometry, chromatography, atomic and molecular spectroscopy; 4. Biophysics and environmental physics. The main topics treated in this conference were isotope production, separation and enrichment as well as stable isotope applications. Also, studies on isotope effects in different fields are reported. Besides reports on isotope effects, exchange and separation, new methods of preparation and labelling the compounds used particularly in nuclear medicine are presented. Environmental studies by means of stable isotope and radon monitoring are described, as well as applications of radiation effects and various nuclear methods in medicine

2003-09-25

234

PIM 2005: The Fourth Conference on Isotopic and Molecular Processes. Abstracts  

International Nuclear Information System (INIS)

The proceedings of the Fourth Conference on Isotopic and Molecular Processes held on September 25 - 27, 2003 in Cluj-Napoca, Romania, contains contributions presented as plenary lectures, oral presentations and posters in four sections, namely: 1. Isotopic separation, labelled compounds and applications; 2. Advanced molecular systems; 3. Mass spectrometry, chromatography, atomic and molecular spectroscopy; 4. Biophysics and environmental physics. The main topics treated in this conference were isotope production, separation and enrichment as well as stable isotope applications. Also, studies on isotope effects in different fields are reported. Besides reports on isotope effects, exchange and separation, new methods of preparation and labelling the compounds used particularly in nuclear medicine are presented. Environmental studies by means of stable isotope and radon monitoring are described, as well as applications of radiation effects and various nuclear methods in medicine

2005-09-22

235

Effect of low molecular fraction of thymus humoral factor on blood formation processes of irradiated mice  

International Nuclear Information System (INIS)

The effect of low-molecular fraction of thymus humoral factor on blood formation in mice irradiated at 4 Gy was studied. It is shown that injection of low-molecular fraction of thymus hymoral factor to irradiated animals affects proliferative processes in spleen and bone marrow, however the degree of the effect depends on the injection scheme of the preparation. Application of mathematical planning methods of the experiment enables to analyze various injection schemes of low-molecular fraction of thymus humoral factor on the investigated indices. The optimal scheme of preparation injection is determined: 1st injection with the dose of 10 mkg/kg following 4 hour after irradiation, 2d injection - with the same dose in 7-21 days

1982-01-01

236

Model Based Control For Interacting And Non-Interacting Level Process Using Labview  

Directory of Open Access Journals (Sweden)

Full Text Available Recent advancements in process industries have enabled the development of combination of interacting and non-interacting of process tank level control system. An experimental setup of three tank level process in interacting and non- interacting mode was studied, to obtain the process models. Different control schemes such as Internal model controller (IMC, IMC-PID and Proportional –Integral and Derivative (PID were implemented. The goal of the model-based controller is to compensate for shifts in the process and maintain the liquid level on target. The performance of different control schemes were investigated through computer simulation.

M.LAVANYA, P.ARAVIND, M.VALLUVAN, DR.B.ELIZABETH CAROLINE

2013-07-01

237

Efficient representations of continuum states for photoionization processes from atomic and molecular targets  

Science.gov (United States)

The investigation of single and double photoionization effects in small atoms and molecules provides a means to probe fundamental quantum mechanical phenomena concerning electron correlation and interference effects. To consider these concepts accurately from first principles requires the construction of the exact final continuum states of a many body problem in atomic double photoionization and of the complicated continuum states in molecular single photoionization. Methods designed for incorporating exterior complex scaling (ECS) have proven very successful towards accomplishing these goals, providing a rigorous framework for describing continuum states involving any number of outgoing electrons with numerical exactness. Furthermore, such methods render solutions that can be interrogated to extract the full richness of information about the photoionization process from the wave function. This work aims to demonstrate the use of exterior complex scaling by first exactly solving the three-body breakup problem of the atomic hydride anion. H-- is the simplest atomic system and is most sensitive to electron correlation effects. The application of ECS with an efficient finite-element discrete variable representation proves quite capable and well-suited for this atomic Coulomb breakup problem. The evolution of this framework to treat molecular problems efficiently with exactness is furthered by the design of a hybrid basis method. The incorporation of analytic Gaussian basis sets ubiquitous in bound state molecular descriptions seems natural for considering molecular continuum states. The hybrid method is described in full detail and applied to completely describe photoionization of molecular H+2 and Li+2 . Photoionization of simple molecular systems offers significantly more complexity in the resulting angular distributions of the ejected electron as the target geometry becomes less atomic-like, i.e., as the internuclear separation increases. In this regard, investigation of photoejection from Li+2 provides a molecular environment ideal for considering the role of internuclear distance in molecular continuum states. With its relatively long equilibrium bond length of R = 5.86 bohr, the extreme target geometry of Li+2 offers the possibility of investigating interference effects caused by the photoelectron de Broglie wavelength becoming comparable with the bond length at relatively low photoejection energies. The aid of the hybrid basis in treating this problem proves substantial, providing an intuitive and robust framework for complete solution of processes involving continuum states of molecular targets.

Yip, Frank L.

238

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.

Hernández Fernández, Rolando A.

239

Molecular model for the regulation of synapse efficacy at the postsynaptic level  

Energy Technology Data Exchange (ETDEWEB)

The regulation of efficacy of a chemical synapse at the postsynaptic level is discussed in terms of the reversible allosteric transitions of the receptor for the neurotransmitter. The proposed model accounts for the regulation of a synapse by its own state of activity and by that of neighbouring synapses on the same neuron. The model predicts persisting changes of efficacy in the time-scale of seconds-minutes compatible with short-term memory processes following, in particular, the scheme of classical conditioning.

Heidmann, T.; Changeux, J.P. (Institut Pasteur, 75 - Paris (France))

1982-12-06

240

Salinity Effects on the Isolation and Subsequent Molecular-Level Characterization of Dissolved Organic Matter.  

Science.gov (United States)

Several studies have demonstrated that dissolved organic matter (DOM) characteristics change down estuarine gradients. These changes are often attributed to photochemical and microbial degradation as well as mixing with different DOM sources. In this study, we collected freshwater DOM and treated it by mixing with artificial seawater. After isolating the DOM with common techniques (C18 solid phase extraction and stirred cell ultrafiltration), we collected mass spectra via electrospray ionization mass spectrometry (ESI-MS) and analyzed the data with principal components analysis and discriminant analysis. Results from these experiments show that when freshwater DOM is subjected to changes in salinity prior to isolation, the isolated DOM assumes characteristics different from those of the initial freshwater DOM isolated in the same manner. These molecular-level changes may result from conformational changes in the DOM as a result of the salinity increase or from shifts in the retention characteristics of ultrafiltration and C18 membranes due to changes in ionic strength. In either case, the resulting fractionation of the DOM may help to explain the relative lack of identifiable terrestrial DOM in the global ocean.

Dalzell, B. J.; Minor, E. C.

2006-12-01

 
 
 
 
241

Toxic effects of pesticide mixtures at a molecular level: their relevance to human health.  

Science.gov (United States)

Pesticides almost always occur in mixtures with other ones. The toxicological effects of low-dose pesticide mixtures on the human health are largely unknown, although there are growing concerns about their safety. The combined toxicological effects of two or more components of a pesticide mixture can take one of three forms: independent, dose addition or interaction. Not all mixtures of pesticides with similar chemical structures produce additive effects; thus, if they act on multiple sites their mixtures may produce different toxic effects. The additive approach also fails when evaluating mixtures that involve a secondary chemical that changes the toxicokinetics of the pesticide as a result of its increased activation or decreased detoxification, which is followed by an enhanced or reduced toxicity, respectively. This review addresses a number of toxicological interactions of pesticide mixtures at a molecular level. Examples of such interactions include the postulated mechanisms for the potentiation of pyrethroid, carbaryl and triazine herbicides toxicity by organophosphates; how the toxicity of some organophosphates can be potentiated by other organophosphates or by previous exposure to organochlorines; the synergism between pyrethroid and carbamate compounds and the antagonism between triazine herbicides and prochloraz. Particular interactions are also addressed, such as those of pesticides acting as endocrine disruptors, the cumulative toxicity of organophosphates and organochlorines resulting in estrogenic effects and the promotion of organophosphate-induced delayed polyneuropathy. PMID:22728724

Hernández, Antonio F; Parrón, Tesifón; Tsatsakis, Aristidis M; Requena, Mar; Alarcón, Raquel; López-Guarnido, Olga

2013-05-10

242

UV-B damage and protection at the molecular level in plants.  

Science.gov (United States)

Influx of solar UV-B radiation (280-320 nm) will probably increase in the future due to depletion of stratospheric ozone. In plants, there are several targets for the deleterious UV-B radiation, especially the chloroplast. This review summarizes the early effects and responses of low doses of UV-B at the molecular level. The DNA molecules of the plant cells are damaged by UV due to the formation of different photoproducts, such as pyrimidine dimers, which in turn can be combatted by specialized photoreactivating enzyme systems. In the chloroplast, the integrity of the thylakoid membrane seems to be much more sensitive than the activities of the photosynthetic components bound within. However, the decrease of mRNA transcripts for the photosynthetic complexes and other chloroplast proteins are among very early events of UV-B damage, as well as protein synthesis. Other genes, encoding defence-related enzymes, e.g., of the flavonoid biosynthetic pathway, are rapidly up-regulated after commencement of UV-B exposure. Some of the cis-acting nucleotide elements and trans-acting protein factors needed to regulate the UV-induced expression of the parsley chalcone synthase gene are known. PMID:24311138

Strid, A; Chow, W S; Anderson, J M

1994-03-01

243

Energy level alignment and electron transport through metal/organic contacts. From interfaces to molecular electronics  

Energy Technology Data Exchange (ETDEWEB)

A new calculational approach to describing metal/organic interfaces. A valuable step towards a better understanding of molecular electronics. Nominated as an outstanding contribution by the Autonomous University of Madrid. In recent years, ever more electronic devices have started to exploit the advantages of organic semiconductors. The work reported in this thesis focuses on analyzing theoretically the energy level alignment of different metal/organic interfaces, necessary to tailor devices with good performance. Traditional methods based on density functional theory (DFT), are not appropriate for analyzing them because they underestimate the organic energy gap and fail to correctly describe the van der Waals forces. Since the size of these systems prohibits the use of more accurate methods, corrections to those DFT drawbacks are desirable. In this work a combination of a standard DFT calculation with the inclusion of the charging energy (U) of the molecule, calculated from first principles, is presented. Regarding the dispersion forces, incorrect long range interaction is substituted by a van der Waals potential. With these corrections, the C60, benzene, pentacene, TTF and TCNQ/Au(111) interfaces are analyzed, both for single molecules and for a monolayer. The results validate the induced density of interface states model.

Abad, Enrique

2013-07-01

244

Molecular-Level Control of Feature Separation in One-Dimensional Nanostructure Assemblies Formed by Biomolecular Nanolithography  

Energy Technology Data Exchange (ETDEWEB)

In this paper, we present a convenient and reliable method to organize small gold nanoparticles (dCORE = 1.5 nm) into linear chains with precisely controlled interparticle spacing over a range of 1.5-2.8 nm through biomolecular nanolithography. Controlling the feature separations of 1 to a few nanometers with angstrom-level precision is a key requirement in electronic and optical applications of nanostructures to tune the properties of the nanostructures and manipulate the interactions between neighboring structures. Here, chains are formed in solution by utilizing functional-group-directed self-assembly to organize ligand-stabilized gold nanoparticles onto DNA templates. The spacing between neighboring nanoparticles can be controlled chemically and tuned at the molecular level by utilizing nanoparticles possessing ligand shells of varying thickness to achieve angstrom-level resolution at spacings of 1.5, 2.1, and 2.8 nm. The small standard deviation (20%) in the values for the interparticle spacing illustrates the reproducibility of the approach. Because the interparticle spacing is enforced by the ligand shell rather than the scaffold, the spacing is uniform even in nonlinear sections of the chain. We further show that the assembly process is robust and produces extended linear nanoparticle chains of up to 1 m in length and a total coverage of >90%. All structures and interparticle spacings were analyzed using transmission electron microscopy. Our results demonstrate the potential of scaffold-assisted assembly approaches for patterning features with tunable dimensions on a length scale that is important for future applications of these materials in nanoscale electronics and optics.

Woehrle, Gerd H.; Warner, Marvin G.; Hutchison, James E.

2004-07-06

245

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

246

An isomerization-induced cage-breaking process in a molecular glass former below Tg  

International Nuclear Information System (INIS)

A recent experimental [P. Karageorgiev, D. Neher, B. Schulz, B. Stiller, U. Pietsch, M. Giersig, L. Brehmer, Nature Mater. 4, 699 (2005)] study has found liquidlike diffusion below the glass-transition temperature in azobenzene-containing materials under irradiation. This result suggests that the isomerization-induced massive mass transport that leads to surface relief gratings formation in these materials, is induced by this huge increase of the matrix diffusion coefficient around the probe. In order to investigate the microscopic origin of the increase of the diffusion, we use molecular dynamics simulations of the photoisomerization of probe dispersed red 1 molecules dispersed inside a glassy molecular matrix. Results show that the increased diffusion is due to an isomerization-induced cage-breaking process. A process that explains the induced cooperative motions recently observed in these photoactive materials.

2011-03-21

247

Multiprobe Spectroscopic Inverstigation of Molecular-level Behavior within Aqueous 1-Butyl-3-methylimidazolium Tetrafluoroborate  

Energy Technology Data Exchange (ETDEWEB)

In this work, an array of molecular-level solvent featuressincluding solute-solvent/solvent-solvent interactions, dipolarity, heterogeneity, dynamics, probe accessibility, and diffusionswere investigated across the entire composition of ambient mixtures containing the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4], and pH 7.0 phosphate buffer, based on results assembled for nine different molecular probes utilized in a range of spectroscopic modes. These studies uncovered interesting and unusual solvatochromic probe behavior within this benchmark mixture. Solvatochromic absorbance probessa watersoluble betaine dye (betaine dye 33), N,N-diethyl-4-nitroaniline, and 4-nitroanilineswere employed to determine ET (a blend of dipolarity/polarizability and hydrogen bond donor contributions) and the Kamlet-Taft indices * (dipolarity/polarizability), R (hydrogen bond donor acidity), and (hydrogen bond acceptor basicity) characterizing the [bmim][BF4] + phosphate buffer system. These parameters each showed a marked deviation from ideality, suggesting selective solvation of the individual probe solutes by [bmim][BF4]. Similar conclusions were derived from the responses of the fluorescent polarity-sensitive probes pyrene and pyrene-1-carboxaldehyde. Importantly, the fluorescent microfluidity probe 1,3-bis(1-pyrenyl)propane senses a microviscosity within the mixture that significantly exceeds expectations derived from simple interpolation of the behavior in the neat solvents. On the basis of results from this probe, a correlation between microviscosity and bulk viscosity was established; pronounced solvent-solvent hydrogen-bonding interactions were implicit in this behavior. The greatest deviation from ideal additive behavior for the probes studied herein was consistently observed to occur in the buffer-rich regime. Nitromethane-based fluorescence quenching of pyrene within the [bmim][BF4] + phosphate buffer system showed unusual compliance with a sphere-of-action quenching model, a further manifestation of the microheterogeneity of the system. Fluorescence correlation spectroscopic results for both small (BODIPY FL) and macromolecular (Texas Red-10 kDa dextran conjugate) diffusional probes provide additional evidence in support of microphase segregation inherent to aqueous [bmim][BF4].

Sarkar, Abhra [Indian Institute of Technology, Delhi; Ali, Maroof [Indian Institute of Technology, Delhi; Baker, Gary A [ORNL; Tetin, Sergey Y. [Abbott Laboratories; Ruan, Qiaoqiao [Abbott Laboratories; Pandey, Siddharth [Indian Institute of Technology, Delhi

2009-01-01

248

Relationships between processing and mechanical properties of injection molded high molecular mass polyethylene + hydroxyapatite composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We apply a macromolecular-orientation approach to produce high molecular weight polyethylene (HMWPE) + hydroxyapatite (HA) ductile composites with the stiffness and strength within the range of human cortical bone. Our composites are produced with different amounts (10 to 50% by weight) of the reinforcement by two procedures: bi-axial rotating drum and twin screw extrusion (TSE). The processing is by conventional injection molding and by Scorim (shear controlled orientation in injection moldi...

Reis, R. L.; Cunha, A. M.; Oliveira, M. J.; Campos, A. R.; Bevis, M. J.

2001-01-01

249

Naphthalene derivatives in the MTO process from a molecular modeling perspective: reactive species or coke?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Currently, basic chemicals in polymer industry are mainly produced by thermal cracking of petroleum, but a promising alternative has been found: methanol-to-olefins (MTO). Methanol can be made from natural gas via syngas, but also from biomass. Molecular modeling of the MTO process has been a challenging topic, yet the reaction mechanism of the active route is starting to get unraveled based on the ‘hydrocarbon pool’ hypothesis [1], where aromatic species play a fundamental role as co-cat...

2009-01-01

250

Mapping Variable Ring Polymer Molecular Dynamics: A Path-Integral Based Method for Nonadiabatic Processes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We introduce mapping-variable ring polymer molecular dynamics (MV-RPMD), a model dynamics for the direct simulation of multi-electron processes. An extension of the RPMD idea, this method is based on an exact, imaginary time path-integral representation of the quantum Boltzmann operator using continuous Cartesian variables for both electronic states and nuclear degrees of freedom. We demonstrate the accuracy of the MV-RPMD approach in calculations of real-time, thermal corre...

Ananth, Nandini

2013-01-01

251

Multi-level post-processing for Korean character recognition using morphological analysis and linguistic evaluation  

CERN Document Server

Most of the post-processing methods for character recognition rely on contextual information of character and word-fragment levels. However, due to linguistic characteristics of Korean, such low-level information alone is not sufficient for high-quality character-recognition applications, and we need much higher-level contextual information to improve the recognition results. This paper presents a domain independent post-processing technique that utilizes multi-level morphological, syntactic, and semantic information as well as character-level information. The proposed post-processing system performs three-level processing: candidate character-set selection, candidate eojeol (Korean word) generation through morphological analysis, and final single eojeol-sequence selection by linguistic evaluation. All the required linguistic information and probabilities are automatically acquired from a statistical corpus analysis. Experimental results demonstrate the effectiveness of our method, yielding error correction r...

Lee, G; Yoo, J H; Lee, Geunbae; Lee, Jong-Hyeok; Yoo, JinHee

1996-01-01

252

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.

2010-03-01

253

Molecular dynamics model of ultraviolet matrix-assisted laser desorption/ionization including ionization processes.  

Science.gov (United States)

A molecular dynamics model of UV-MALDI including ionization processes is presented. In addition to the previously described breathing sphere approach developed for simulation of laser ablation/desorption of molecular systems, it includes radiative and nonradiative decay, exciton hopping, two pooling processes, and electron capture. The results confirm the main conclusions of the continuum model of Knochenmuss, Anal. Chem. 2003, 75, 2199, but provide a much more detailed description of the interaction between ablation/desorption and ionization processes in the critical early time regime. Both desorption and ablation regimes generate free ions, and yields are in accordance with experiment. The first molecular ions are emitted at high velocities shortly before neutral desorption begins, because of surface charging caused by electron escape from the top of the sample. Later ions are entrained and thermalized in the plume of neutral molecules and clusters. Clusters are found to be stable on a nanosecond time scale, so the ions in them will be released only slowly, if at all. Exciton hopping rate and the mean radius for ion recombination are shown to be key parameters that can have a significant effect on net ion yield. PMID:16853990

Knochenmuss, Richard; Zhigilei, Leonid V

2005-12-01

254

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2012-01-01

255

The level of knowledge about the planning of training process of female engaged in recreational fitness  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of the study was to determine the level of knowledge about the planning of training process of female engaged in recreational fitness. The main method of investigation was questioning. The study involved 100 female aged 16-47 years engaged in fitness in three fitness centers in Gdansk and Sopot. The general level of knowledge of the planning of training process and its relationship with age, training experience and level of education was revealed.

Jagiello Wladyslaw

2011-07-01

256

Energetic and structural evolution of gold nanowire under heating process: A molecular dynamics study  

Energy Technology Data Exchange (ETDEWEB)

The energetic and structural evolution of a squared gold nanowire under heating process is investigated via molecular dynamics with many-body potential. The simulations reveal that the nanowire undergoes distinct energetic and structural developments during the following four heating processes: low temperature, melting, breaking and high temperature. The cross-section of nanowire is found to change from a square to a circle shape with rising temperature at first. A neck is then found to be initiated above the overall melting point, followed by the formation of a two- to five-atom-thick chain structure before the breaking of neck. The nanowire transforms to a spherical cluster after the final breaking.

Zhang Yang [Department of Physics, and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen 361005 (China); Wen Yuhua, E-mail: yhwen@xmu.edu.c [Department of Physics, and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen 361005 (China); Zheng Jincheng, E-mail: jczheng@xmu.edu.c [Department of Physics, and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen 361005 (China); Zhu Zizhong, E-mail: zzhu@xmu.edu.c [Department of Physics, and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen 361005 (China)

2009-09-14

257

Molecular magnetic resonance imaging  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Molecular MRI (mMRI) is a special implementation of Molecular Imaging for the non-invasive visualisation of biological processes at the cellular and molecular level. More specifically, mMRI comprises the contrast agent-mediated alteration of tissue relaxation times for the detection and localisation of molecular disease markers (such as cell surface receptors, enzymes or signaling molecules), cells (e.g. lymphocytes, stem cells) or therapeutic drugs (e.g. liposomes, viral particles). MRI yiel...

Hengerer, A.; Grimm, J.

2006-01-01

258

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

259

THE APPLICATION OF FEATURE TECHNOLOGY IN DEVELOPING A CAD-BASED HIGH LEVEL PROCESS PLANNING SYSTEM  

Directory of Open Access Journals (Sweden)

Full Text Available High-level process planning plays an important role in determining candidate process domains at the configuration design stage. Changing the process domains later increases the product development cycle and the product development cost. Therefore, determining the most appropriate manufacturing processes at the beginning stages of the design process becomes critical. However, high-level process planning systems have traditionally lacked integration of design synthesis and design evaluation. The objective of this paper is to propose a CAD-based high-level process planning system that will help designers decide whether or not the designs are worth pursuing. A hybrid approach incorporating design by feature and feature recognition approaches is proposed and implemented. Synergizing both advantages of both approaches will reduce the complexity of feature recognition algorithm without sacrificing the flexibility in creating a part model.

Ade Febransyah

2005-01-01

260

Processing of low- and medium-level radioactive waste. Chapter 3  

International Nuclear Information System (INIS)

In a Dutch government policy formulated in 1984, it has been stated that in the Netherlands one location has to be adapted for, among other things, processing of low- and medium-level radioactive waste. This chapter deals with the radioactive waste to be processed and the processing facility to be realized. (author). 3 figs

1989-03-01

 
 
 
 
261

Advice concerning the advantages of a reference incinerator for low-level and intermediate-level radioactive waste processing  

International Nuclear Information System (INIS)

In this report, an inventory is presented of new incinerators and flue gas filters used in low and intermediate-level radioactive waste combustion. It is argued that a 'reference equipment' for the combustion of solid and liquid low- and intermediate-level wastes best meets existing Dutch radiation protection standards. A cost-benefit analysis of such an equipment is given including annual costs of investment, capital and exploration. A separate combustion process of organic liquids and carrions is considered finally. (G.J.P.)

1985-01-01

262

Research Concerning Influence of Worm Face Gear Finishing Process upon Noise and Vibration Level  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A study was performed to evaluate noise and vibration level of worm face gear finish. Vibration and noise monitoring data were gathered from 6 sets of worm plane gears run during a evaluation study. A drop o vibration level was successful recording, noise level remain almost the same as noise level record before finishing process was perform. A solution for fly cutter hobbing's particular problem was propose.

Ion Gavril??; Vasile Bolo?

2011-01-01

263

Research Concerning Influence of Worm Face Gear Finishing Process upon Noise and Vibration Level  

Directory of Open Access Journals (Sweden)

Full Text Available A study was performed to evaluate noise and vibration level of worm face gear finish. Vibration and noise monitoring data were gathered from 6 sets of worm plane gears run during a evaluation study. A drop o vibration level was successful recording, noise level remain almost the same as noise level record before finishing process was perform. A solution for fly cutter hobbing's particular problem was propose.

Ion Gavril??

2011-11-01

264

Phase behaviour of macromolecular liquid crystalline materials. Computational studies at the molecular level  

CERN Document Server

Molecular simulations provide an increasingly useful insight into the static and dynamic characteristics of materials. In this thesis molecular simulations of macro-molecular liquid crystalline materials are reported. The first liquid crystalline material that has been investigated is a side chain liquid crystal polymer (SCLCP). In this study semi-atomistic molecular dynamics simulations have been conducted at a range of temperatures and an aligning potential has been applied to mimic the effect of a magnetic field. In cooling the SCLCP from an isotropic melt, microphase separation was observed yielding a domain structure. The application of a magnetic field to this structure aligns the domains producing a stable smectic mesophase. This is the first study in which mesophases have been observed using an off-lattice model of a SCLCP. The second material that has been investigated is a dendrimer with terminal mesogenic functionalization. Here, a multi-scale approach has been taken with Monte Carlo studies of a s...

Stimson, L M

2003-01-01

265

Towards system-level understanding of baculovirus host cell interactions: from molecular fundamental studies to large-scale proteomics approaches  

Directory of Open Access Journals (Sweden)

Full Text Available Baculoviruses are insect viruses extensively exploited as eukaryotic protein expression vectors. Molecular biology studies have provided exciting discoveries on virus-host interactions, but the application of omic high throughput techniques on the baculovirus-insect cell system has been hampered by the lack of host genome sequencing. While a broader, systems level analysis of biological responses to infection is urgently needed, recent advances on proteomic studies have yielded new insights on the impact of infection on the host cell. These works are reviewed and critically assessed in the light of current biological knowledge of the molecular biology of baculoviruses and insect cells.

FranciscaMonteiro

2012-11-01

266

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 pro...

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

2009-01-01

267

Study of multivariable fuzzy control for density and level of suspension in heavy media coal processing  

Energy Technology Data Exchange (ETDEWEB)

The dynamic properties of density and level system of heavy medium suspension in heavy media coal processing are analyzed, and the multivariable fuzzy control system of level and density is studied. This control system consists of two independent fuzzy controllers which are responsible to adjust level and density of suspension in the mixing tank. Simulation shows that this method is simple in designing rule and efficient in heavy medium circulation control. The experimental results, tested in low density suspension circulation control of main separation and re-separation process in heavy media coal processing, show that this control system can meet the need of suspension circulation control. 10 refs., 4 figs., 2 tabs.

Meng, F.; Wang, Y.; Jiang, J.; Wang, J. [China University of Mining and Technology, Xuzhou (China)

2005-03-01

268

Molecular dynamics simulation of cluster-beam-surface impact processes for metallic phases  

International Nuclear Information System (INIS)

An optimised version of the DLPOLY molecular dynamics simulation code has been used to study the cluster-beam-surface impact processes for the metallic phase. The interaction of an energetic cluster of atoms with a solid surface was investigated using the Finnis-Sinclair many-body potential. The characteristics of the collision range from soft landing ( 3 eV/atom) are studied. Modification of the surface, exposed to highly energetic cluster-beams, was studied by monitoring the molecular dynamics configurations of the system in real time and defining the critical impact energies, necessary to produce implantation. The density and temperature distributions in the system of cluster-substrate under highly energetic irradiations was investigated in detail

2000-01-01

269

Isolation and Identification of Listeria monocytogenes in Processed Meat by a Combined Cultural-molecular Method  

Directory of Open Access Journals (Sweden)

Full Text Available The isolation and identification of Listeria monocytogenes in processed meat samples by a combined cultural-molecular method is described. It allows the identification of Listeria strains by means of a hybridization technique with a specific DNA probe directed to the listerial internalin gene. The specificity of this method was found to be 100% and sensitivity was as low as 1 CFU/2.5 g of food sample. A total of 278 meat samples were tested in comparison with PCR and conventional cultural assays. A total of 42 (15.4% L. monocytogenes were detected. PCR analysis gave 3 false negative results and culture failed to detect the Listeria in 5 cases. With this cultural-molecular method the identification and quantitative detection of L. monocytogenes were achieved within 36 hours and no false positive or negative tests were obtained, thus fitting most food industry requirements.

Angela Ingianni

2007-01-01

270

Processes of DNA condensation induced by multivalent cations: Approximate annealing experiments and molecular dynamics simulations  

International Nuclear Information System (INIS)

The condensation of DNA induced by spermine is studied by atomic force microscopy (AFM) and molecular dynamics (MD) simulation in this paper. In our experiments, an equivalent amount of multivalent cations is added to the DNA solutions in different numbers of steps, and we find that the process of DNA condensation strongly depends on the speed of adding cations. That is, the slower the spermine cations are added, the slower the DNA aggregates. The MD and steered molecular dynamics (SMD) simulation results agree well with the experimental results, and the simulation data also show that the more steps of adding multivalent cations there are, the more compact the condensed DNA structure will be. This investigation can help us to control DNA condensation and understand the complicated structures of DNA—cation complexes. (interdisciplinary physics and related areas of science and technology)

2013-09-01

271

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 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

2006-12-01

272

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

273

Low-Level Image Processing Architectures: Compared for Some Non-Linear Recursive Neighbourhood Operations.  

Science.gov (United States)

A method is developed for the comparison of computer architectures for image processing which have been designed to work for low-level operations. A division is made between three principally different groups: square processor arrays, linear processor arr...

E. R. Komen

1990-01-01

274

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

1996-01-01

275

Low-level wastewater treatment facility process control operational test report  

Energy Technology Data Exchange (ETDEWEB)

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.

Bergquist, G.G.

1996-04-08

276

The level of knowledge about the planning of training process of males engaged in recreational fitness.  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of the study was to determine the level of knowledge about the planning of training process of males engaged in recreational fitness. The main method of investigation was questioning. The study involved 100 males aged 16-47 years engaged in fitness in three fitness centers in Gdansk and Sopot. The general level of knowledge of the planning of training process and its relationship with age and training experience was revealed.

Jagiello, Wladyslaw

2011-08-01

277

DEEP LEVEL DEFECTS IN SILICON AFTER BEAM PROCESSING IN THE SOLID PHASE REGIME  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recent investigations of defects in cw beam processed silicon are reviewed, with emphasis on electrical characterization. Defect levels have been observed in concentrations of 1014 - 1015 cm-3 in surface layers of silicon wafers, either ion-implanted or virgin, following beam processing in the solid phase regime. Deep Level Transient Spectroscopy (DLTS) has provided a unique insight into the microscopic nature of these defects, and the mechanisms of defect production. Practical informations c...

Chantre, A.

1983-01-01

278

Technical feasibility of transuranic tank waste processing in high-level waste vitrification facility  

Energy Technology Data Exchange (ETDEWEB)

The objective of this study is to determine the technical feasibility of processing transuranic tank waste in a high-level waste vitrification facility. This is achieved by performing an impact assessment of a reference case high-level waste facility modified to separately process transuranic waste. Data are presented for Hanford Site transuranic wastes and are compared against established waste acceptance criteria for the Waste Isolation Pilot Plant program. Schedule and cost impacts are evaluated for the proposed transuranic campaign.

Crawford, T.W.; Manuel, A.F., Westinghouse Hanford

1996-07-26

279

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

280

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

 
 
 
 
281

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Our aim was to determine the direction of inter-hemispheric communication in a phonological task, in regions involved in different levels of processing. Effective connectivity analysis was conducted on fMRI data from 39 children (9–15) performing rhyming judgment on spoken words. The results show interaction between hemispheres at multiple levels: There is unidirectional transfer of information from right to left at the sensory level of primary auditory cortex. Second, bidirectional connect...

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

2010-01-01

282

Electrospray ionization mass spectrometry: chemical processes involved in the ion formation from low molecular weight organic compounds  

International Nuclear Information System (INIS)

An overview of the current literature on the chemical processes involved in the ion formation from low molecular weight organic compounds by electrospray ionization mass spectrometry is given. (author)

2006-01-01

283

Dynamics of two-photon processes in two-level system  

International Nuclear Information System (INIS)

A method of partial elimination of boson variables is developed and on its basis exact hierarchies for two-photon processes in a macroscopic two-level system are obtained. The dynamics of a cascade-type and of combination scattering processes is examined

1984-01-01

284

Quantum Catalytic Extraction Process trademark:Applications to low-level radioactive waste  

International Nuclear Information System (INIS)

This presentation details the Quantum method for catalytic extraction processing of low-level radioactive wastes. Resource recovery, waste volume reduction, and fundamentals of the processing technology are discussed. The results of two case studies, and a description of two demonstration units are provided

1994-10-17

285

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

286

Molecular Insight Into the Energy Levels at the Organic Donor/Acceptor Interface: A QM/MM Study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present an investigation of the band levels and charge transfer (CT) states at the interface between two organic semiconductors, metal-free phthalocyanine (H2Pc) and 3,4,9,10-perylenetetracarboxylic bisbenzimidazole (PTCBI), using a combined quantum mechanics/molecular mechanics (QM/MM) technique. Near the organic–organic interface, significant changes from the bulk, as large as 0.2 eV, are found in the excited state energies, ionization potentials, and electron affinities, due to differ...

Yost, Shane Robert; Wang, Lee-ping; Voorhis, Troy

2011-01-01

287

News Note: Scientists identify molecular link between BRCA1 protein levels and obesity  

Science.gov (United States)

NCI researchers have defined a possible molecular link between breast cancer risk and obesity. New study results show that a protein called C-terminal binding protein (CtBP) acts to control a gene linked to breast cancer risk in rapidly growing cells by monitoring and responding to how the cells use and store energy (metabolic state).

288

The molecular genetics of the incision step in the DNA excision repair process  

International Nuclear Information System (INIS)

In this historical review one particular aspect of excision repair, DNA incision, and how it is controlled at the genetic level in bacteriophage, bacteria, S. cerevisae, D. melanogaster, rodent cells and humans is examined. In phage T4, DNA is incised by a DNA glycosylase-AP endonuclease coded for by the denV gene. In E. coli, products of three genes, uvrA, uvrB and uvrC, are required to form UVRABC excinuclease that cleaves DNA and releases a fragment 12-13 nucleotides long containing the damage site. In S. cerevisiae, genes complementing five mutants of the RAD3 epistasis group, rad1, rad2, rad3, rad4 and rad10 have been cloned and analyzed. Rodent cells sensitive to a variety of mutagenic agents and deficient in excision repair are being used in molecular studies to identify and clone human repair genes (e.g. ERCC1) capable of complementing mammalian repair defects. Most studies of the human system, have been done with cells isolated from patients xeroderma pigmentosum, and these are now beginning to be characterized at the molecular level. (author)

1988-01-01

289

Molecular genetics of the incision step in the DNA excision repair process  

Energy Technology Data Exchange (ETDEWEB)

In this historical review one particular aspect of excision repair, DNA incision, and how it is controlled at the genetic level in bacteriophage, bacteria, S. cerevisae, D. melanogaster, rodent cells and humans is examined. In phage T4, DNA is incised by a DNA glycosylase-AP endonuclease coded for by the denV gene. In E. coli, products of three genes, uvrA, uvrB and uvrC, are required to form UVRABC excinuclease that cleaves DNA and releases a fragment 12-13 nucleotides long containing the damage site. In S. cerevisiae, genes complementing five mutants of the RAD3 epistasis group, rad1, rad2, rad3, rad4 and rad10 have been cloned and analyzed. Rodent cells sensitive to a variety of mutagenic agents and deficient in excision repair are being used in molecular studies to identify and clone human repair genes (e.g. ERCC1) capable of complementing mammalian repair defects. Most studies of the human system, have been done with cells isolated from patients xeroderma pigmentosum, and these are now beginning to be characterized at the molecular level.

Rubin, J.S.

1988-09-01

290

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

291

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

292

The Weibull manifold in low-level image processing: an application to automatic image focusing.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we introduce a novel framework for low-level image processing and analysis. First, we process images with very simple, difference-based filter functions. Second, we fit the 2-parameter Weibull distribution to the filtered output. This maps each image to the 2D Weibull manifold. Third, we exploit the information geometry of this manifold and solve low-level image processing tasks as minimisation problems on point sets. For a proof-of-concept example, we examine the image autofoc...

Zografos, Vasileios; Lenz, Reiner; Felsberg, Michael

2013-01-01

293

Thickness control of molecular beam epitaxy grown layers at the 0.01–0.1 monolayer level  

International Nuclear Information System (INIS)

Electron tunnelling through semiconductor tunnel barriers is exponentially sensitive to the thickness of the barrier layer, and in the most common system, the AlAs tunnel barrier in GaAs, a one monolayer variation in thickness results in a 300% variation in the tunnelling current for a fixed bias voltage. We use this degree of sensitivity to demonstrate that the level of control at 0.06 monolayer can be achieved in the growth by molecular beam epitaxy, and the geometrical variation of layer thickness across a wafer at the 0.01 monolayer level can be detected. (paper)

2012-08-01

294

Urea transporters in kidney: molecular analysis and contribution to the urinary concentrating process1.  

Science.gov (United States)

Facilitated urea transporters (UTs) are responsible for urea accumulation in the renal inner medulla of the mammalian kidney and therefore play a central role in the urinary concentrating process. Recently, the cDNAs encoding three members of the UT family, UT1, UT2, and UT3 have been cloned. These transporters are expressed in different structures of the mammalian kidney. In rat, UT1 resides in the apical membrane of terminal inner medullary collecting ducts, where it mediates vasopressin-regulated urea reabsorption. UT2 and UT3 are located in descending thin limbs of Henle's loop and descending vasa recta, respectively, and participate in urinary recycling processes, which minimize urea escape from the inner medulla. UT1 and UT2 are regulated independently and respond differently to changes in dietary protein content and hydration state. Identification and characterization of these urea transporters advances our understanding of the molecular basis and regulation of the urinary concentrating mechanism. PMID:9729501

Tsukaguchi, H; Shayakul, C; Berger, U V; Hediger, M A

1998-09-01

295

Molecular dynamics simulations of crystal growth from melted silicon: Defect formation processes  

Energy Technology Data Exchange (ETDEWEB)

Molecular dynamics calculations have been performed to simulate crystal growth from melted silicon (Si) and defect formation processes based on the ordinary Langevin equation employing the Tersoff interatomic potential. The findings of this investigation are as follows: (1) The [110] bonds at the solid-liquid interface induce the eclipsed configurations or hexagonal Si structures which stabilize microfacets composed of the {l{underscore}brace}111{r{underscore}brace} planes. (2) Defect formation during crystal growth processes is due to misorientations at the {l{underscore}brace}111{r{underscore}brace} interfaces which result in an elementary grown-in defect structure including five- and seven-member rings. (3) The elementary grown-in defect migrates in c-Si by bond-switching motions during further crystal pulling or annealing.

Ishimaru, Manabu; Motooka, Teruaki

1999-07-01

296

A molecular dynamics study of structural transition of Ti during the rapid quenching process  

Energy Technology Data Exchange (ETDEWEB)

The structural transitions of Ti during two different quenching processes (Q1: 7.5 Multiplication-Sign 10{sup 11} K/s, Q2: 2.0 Multiplication-Sign 10{sup 14} K/s) were studied using molecular dynamics simulations. The calculated pair-correlation function agrees acceptably with available experimental data. This work gives the structural properties, including the variations with temperature of pair-correlation function, bond-angle distribution function, bond pairs and Voronoi indices, in both rapid quenching processes. Our results indicated that the liquid Ti transformed to hcp phase at the temperature about of 400 K under the quenching condition Q1 while the liquid Ti was frozen into a glass state at the temperature about of 800 K under the quenching condition Q2.

Xia, J.H., E-mail: jhxiahf@163.com [Department of Physics, Chongqing University of Arts and Sciences, Chongqing 402160 (China); Cheng, Z.F.; Shi, D.P.; Xiao, Xu-yang [Department of Physics, Chongqing University of Arts and Sciences, Chongqing 402160 (China)

2012-06-15

297

Molecular dynamics simulation of solid-liquid phase change process for Si  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the numerical computation of the solid-liquid phase change for silicon with the Molecular Dynamic (MD) simulation method (Haile (1992)). The Stillinger-Weber (SW) potential (Stillinger et al. (1985)) was used for this calculation. 216 molecules were located in the diamond structure at the beginning. Both the melting and the solidification processes were calculated. The cooling and the heating rates were set at the same value 46.2 [TK/s]. It was concluded that the melting temperature and the melting entropy were almost in good agreement with the experimental data, respectively. Further the result suggests that this process is the first order phase transition. The computed solidifying temperature was lower than the experimental one by 14%. The computed self diffusion coefficient of silicon for the range between 1,500 [K] and 2,020 [K] agrees favorably with that by Kakimoto (1995).

Matsushita, Koichiro; Hirano, Hiroyuki; Ozoe, Hiroyuki

1999-07-01

298

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

Science.gov (United States)

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; Chin, Alex W.; Almeida, Javier; Huelga, Susana F.; Plenio, Martin B.

2013-12-01

299

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

2001-11-15

300

Ultrasmall volume molecular isothermal amplification in microfluidic chip with advanced surface processing  

Energy Technology Data Exchange (ETDEWEB)

In this paper, we developed a metal micro-fluidic chip with advanced surface processing for ultra-small volume molecular isothermal amplification. This method takes advantages of the nucleic acid amplification with good stability and consistency, high sensitivity about 31 genomic DNA copies and bacteria specific gene identification. Based on the advanced surface processing, the bioreaction assays of nucleic acid amplification was dropped about 392nl in volume. A high numerical aperture confocal optical detection system was advanced to sensitively monitor the DNA amplification with low noise and high power collecting fluorescence near to the optical diffraction limit. A speedy nucleic acid isothermal amplification was performed in the ultra-small volume microfluidic chip, where the time at the inflexions of second derivative to DNA exponential amplified curves was brought forward and the sensitivity was improved about 65 folds to that of in current 25{mu}l Ep-tube amplified reaction, which indicates a promising clinic molecular diagnostics in the droplet amplification.

Huang Guoliang; Yang Xiaoyong [Department of Biomedical Engineering, the School of Medicine, Tsinghua University, Beijing, 100084 (China); Ma Li; Yang Xu, E-mail: tshgl@tsinghua.edu.cn [National Engineering Research Center for Beijing Biochip Technology, Beijing, 102206 (China)

2011-01-01

 
 
 
 
301

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

302

Study the sensitivity of molecular functional groups to bioethanol processing in lipid biopolymer of co-products using DRIFT molecular spectroscopy  

Science.gov (United States)

To date, there is no study on bioethanol processing-induced changes in molecular structural profiles mainly related to lipid biopolymer. The objectives of this study were to: (1) determine molecular structural changes of lipid related functional groups in the co-products that occurred during bioethanol processing; (2) relatively quantify the antisymmetric CH 3 and CH 2 (ca. 2959 and 2928 cm -1, respectively), symmetric CH 3 and CH 2 (ca. 2871 and 2954 cm -1, respectively) functional groups, carbonyl C dbnd O ester (ca. 1745 cm -1) and unsaturated groups (CH attached to C dbnd C) (ca. 3007 cm -1) spectral intensities as well as their ratios of antisymmetric CH 3 to antisymmetric CH 2, and (3) illustrate the molecular spectral analyses as a research tool to detect for the sensitivity of individual moleculars to the bioethanol processing in a complex plant-based feed and food system without spectral parameterization. The hypothesis of this study was that bioethanol processing changed the molecular structure profiles in the co-products as opposed to original cereal grains. These changes could be detected by infrared molecular spectroscopy and will be related to nutrient utilization. The results showed that bioethanol processing had effects on the functional groups spectral profiles in the co-products. It was found that the CH 3-antisymmetric to CH 2-antisymmetric stretching intensity ratio was changed. The spectral features of carbonyl C dbnd O ester group and unsaturated group were also different. Since the different types of cereal grains (wheat vs. corn) had different sensitivity to the bioethanol processing, the spectral patterns and band component profiles differed between their co-products (wheat DDGS vs. corn DDGS). The multivariate molecular spectral analyses, cluster analysis and principal component analysis of original spectra (without spectral parameterization), distinguished the structural differences between the wheat and wheat DDGS and between the corn and corn DDGS in the antisymmetric and symmetric CH 3 and CH 2 spectral region (ca. 2994-2800 cm -1) and unsaturated group band region (3025-2996 cm -1). Further study is needed to quantify molecular structural changes in relation to nutrient utilization of lipid biopolymer.

Yu, Peiqiang

2011-11-01

303

Gene expression patterns unveil a new level of molecular heterogeneity in colorectal cancer.  

Science.gov (United States)

The recognition that colorectal cancer (CRC) is a heterogeneous disease in terms of clinical behaviour and response to therapy translates into an urgent need for robust molecular disease subclassifiers that can explain this heterogeneity beyond current parameters (MSI, KRAS, BRAF). Attempts to fill this gap are emerging. The Cancer Genome Atlas (TGCA) reported two main CRC groups, based on the incidence and spectrum of mutated genes, and another paper reported an EMT expression signature defined subgroup. We performed a prior free analysis of CRC heterogeneity on 1113 CRC gene expression profiles and confronted our findings to established molecular determinants and clinical, histopathological and survival data. Unsupervised clustering based on gene modules allowed us to distinguish at least five different gene expression CRC subtypes, which we call surface crypt-like, lower crypt-like, CIMP-H-like, mesenchymal and mixed. A gene set enrichment analysis combined with literature search of gene module members identified distinct biological motifs in different subtypes. The subtypes, which were not derived based on outcome, nonetheless showed differences in prognosis. Known gene copy number variations and mutations in key cancer-associated genes differed between subtypes, but the subtypes provided molecular information beyond that contained in these variables. Morphological features significantly differed between subtypes. The objective existence of the subtypes and their clinical and molecular characteristics were validated in an independent set of 720 CRC expression profiles. Our subtypes provide a novel perspective on the heterogeneity of CRC. The proposed subtypes should be further explored retrospectively on existing clinical trial datasets and, when sufficiently robust, be prospectively assessed for clinical relevance in terms of prognosis and treatment response predictive capacity. Original microarray data were uploaded to the ArrayExpress database (http://www.ebi.ac.uk/arrayexpress/) under Accession Nos E-MTAB-990 and E-MTAB-1026. PMID:23836465

Budinska, Eva; Popovici, Vlad; Tejpar, Sabine; D'Ario, Giovanni; Lapique, Nicolas; Sikora, Katarzyna Otylia; Di Narzo, Antonio Fabio; Yan, Pu; Hodgson, John Graeme; Weinrich, Scott; Bosman, Fred; Roth, Arnaud; Delorenzi, Mauro

2013-09-01

304

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

305

MILLIMETER-SCALE GENETIC GRADIENTS AND COMMUNITY-LEVEL MOLECULAR CONVERGENCE IN A HYPERSALINE MICROBIAL MAT  

Energy Technology Data Exchange (ETDEWEB)

To investigate the extent of genetic stratification in structured microbial communities, we compared the metagenomes of 10 successive layers of a phylogenetically complex hypersaline mat from Guerrero Negro, Mexico. We found pronounced millimeter-scale genetic gradients that are consistent with the physicochemical profile of the mat. Despite these gradients, all layers displayed near identical and acid-shifted isoelectric point profiles due to a molecular convergence of amino acid usage indicating that hypersalinity enforces an overriding selective pressure on the mat community.

Fenner, Marsha W; Kunin, Victor; Raes, Jeroen; Harris, J. Kirk; Spear, John R.; Walker, Jeffrey J.; Ivanova, Natalia; Mering, Christian von; Bebout, Brad M.; Pace, Norman R.; Bork, Peer; Hugenholtz, Philip

2008-04-30

306

Millimeter-scale genetic gradients and community-level molecular convergence in a hypersaline microbial mat  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To investigate the extent of genetic stratification in structured microbial communities, we compared the metagenomes of 10 successive layers of a phylogenetically complex hypersaline mat from Guerrero Negro, Mexico. We found pronounced millimeter-scale genetic gradients that were consistent with the physicochemical profile of the mat. Despite these gradients, all layers displayed near-identical and acid-shifted isoelectric point profiles due to a molecular convergence of amino-acid usage, ind...

2008-01-01

307

High level liquid waste treatment process: Reducing risk and capitalizing on high value isotopes  

Energy Technology Data Exchange (ETDEWEB)

A processing system has been developed to treat highly radioactive liquid waste. This system was designed to treat the liquid waste currently stored in the 324 Building, High Level Vault tanks (Tanks 104, 105, and 107). Tank 105 contains a high level of Sr-90, an isotope used in the medical isotope program to produce Y-90. An objective of the processing system is to retrieve the Sr-90 from tank 105 in a form that can be readily reconstituted for future use in the medical isotope program. The processing strategy has six sequential processing steps. The first step is to transfer the tank liquids into a batch precipitator, where the pH will be increased and metal hydroxides will be precipitated. The slurry will then be filtered to remove the precipitate. The remaining filtrate will be precipitated as a carbonate to remove the Sr-90. The precipitated Sr-90 will be captured on another filter system. The final filtrate will be passed through an ion exchange column to remove the Cs-137, thus leaving an eluant stream of low-level liquid waste. The eluant will be either processed in an existing waste treatment transfer system or evaporated. Equipment for the entire process is skid mounted and will be operated in a hot cell in the 324 Building. Results from the first waste-processing campaign will be presented at the conference. A project background, and detailed description of the processing system are described herein.

Hosaka, T.Y.; Sevigny, G.J.; Schlender, M.H. [Pacific Northwest National Lab., Richland, WA (United States)

1996-12-31

308

Evolution of the C4 photosynthetic pathway: events at the cellular and molecular levels.  

Science.gov (United States)

The biochemistry and leaf anatomy of plants using C4 photosynthesis promote the concentration of atmospheric CO2 in leaf tissue that leads to improvements in growth and yield of C4 plants over C3 species in hot, dry, high light, and/or saline environments. C4 plants like maize and sugarcane are significant food, fodder, and bioenergy crops. The C4 photosynthetic pathway is an excellent example of convergent evolution, having evolved in multiple independent lineages of land plants from ancestors employing C3 photosynthesis. In addition to C3 and C4 species, some plant lineages contain closely related C3-C4 intermediate species that demonstrate leaf anatomical, biochemical, and physiological characteristics between those of C3 plants and species using C4 photosynthesis. These groups of plants have been extremely useful in dissecting the modifications to leaf anatomy and molecular biology, which led to the evolution of C4 photosynthesis. It is now clear that great variation exists in C4 leaf anatomy, and diverse molecular mechanisms underlie C4 biochemistry and physiology. However, all these different paths have led to the same destination-the expression of a C4 CO2 concentrating mechanism. Further identification of C4 leaf anatomical traits and molecular biological components, and understanding how they are controlled and assembled will not only allow for additional insights into evolutionary convergence, but also contribute to sustainable food and bioenergy production strategies. PMID:23708978

Ludwig, Martha

2013-11-01

309

GLYCOSIDASES IN HUMAN BLOOD PLASMA AND URINE. MOLECULAR FORMS AND ACTIVITY LEVELS  

Directory of Open Access Journals (Sweden)

Full Text Available The isoe lect r i c f ocusing p a t terns and pH activity cur ves of f i ve glycosidas e e nzymes i n blood plasma and ur i ne were s t ud i e d . This s tudy demons trated the presence o f a sing le molecular f onn in a -glucosidase and of two mole cul a r fonns of the enzymes H-a ce t yl-B-D-gluco sarni nidase, Na c e t y l -•p-D-g a l a c t o s amin i ua s e and S-glucuronidase i n both plasma and urine . B-Galactosidase existed as a s i ng le major molecular f orm i n p l asma and a t l e a st t wo molecular forms in urine. Spe cific activity of each~ le n zyme was determined in p lasma and urine The validity o f taking the ratio between two e n zvrne activities as an index for scr een .l.ng of fr ene t ic di s e a s e is discussed.

Reza Seyed Yazdani

1982-05-01

310

Recent Process and Equipment Improvements to Increase High Level Waste Throughput at The Defense Waste Processing Facility (DWPF)  

International Nuclear Information System (INIS)

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 an 8 % waste throughput increase over the standard 28 % waste loading based upon operational efficiencies. Improvements in canister production include the pour spout heated bellows liner (7 %), 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 14 %. 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. (authors)

2008-02-24

311

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

International Nuclear Information System (INIS)

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

2008-02-24

312

Immunohistochemistry of tissue prepared by a molecular-friendly fixation and processing system.  

Science.gov (United States)

A recently introduced histologic fixative (Universal Molecular Fixative [UMFIX]) has been shown to preserve macromolecules in tissue at ambient temperature. When UMFIX-exposed tissues are processed by a formalin-free, microwave-assisted rapid processing system, the resulting paraffin blocks retain good histomorphology and intact nucleic acids suitable for expression microarray analysis. Because UMFIX may be used as an alternative to formalin, the authors set out to study the effect of this new fixation and processing system on immunohistochemistry (IHC) by analyzing a range of human neoplastic and non-neoplastic specimens. Parallel slices from surgically removed specimens were fixed in formalin and UMFIX and processed in a rapid microwave-assisted tissue processor. IHC was performed following routine procedures. The staining for those antibodies that normally required antigen retrieval was carried out with and without that step. The intensity and pattern of reactions were compared in 144 tissue samples fixed by the two methods using 70 monoclonal and polyclonal antibodies. The intensity of IHC reactions for most cytoplasmic antigens was generally equal or stronger in UMFIX tissues. This was particularly true with intermediate filaments and HercepTest, where the antigen retrieval step became unnecessary. Conversely, there was a decrease in the intensity of reactions for HepPar1, bcl-2, and three nuclear antigens (Ki-67, TTF-1, and estrogen receptor). Increasing their exposure times optimized the sensitivity of the latter four antibodies. The study shows that IHC staining results of tissues fixed in UMFIX and processed by the microwave-assisted system are comparable to those obtained on formalin-fixed, similarly processed specimens. There is an enhancement of the sensitivity of few antibodies in UMFIX-exposed tissue, rendering antigen retrieval unnecessary. This increased sensitivity may be due to the effect of eliminating formalin from fixation and processing or the microwave energy. PMID:16082256

Nadji, M; Nassiri, M; Vincek, V; Kanhoush, R; Morales, A R

2005-09-01

313

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

1997-10-10

314

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

1997-10-12

315

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

Energy Technology Data Exchange (ETDEWEB)

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.

Costin, L.S. [Sandia National Labs., Albuquerque, NM (United States)

1997-12-31

316

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

317

Relationship between processing and mechanical properties of injection molded high molecular mass polyethylene + hydroxyapatite composites  

Energy Technology Data Exchange (ETDEWEB)

We apply a macromolecular-orientation approach to produce high molecular weight polyethylene (HMWPE) + hydroxyapatite (HA) ductile composites with the stiffness and strength within the range of human cortical bone. Our composites are produced with different amounts (10 to 50% by weight) of the reinforcement by two procedures: bi-axial rotating drum and twin screw extrusion (TSE). The processing is by conventional injection molding and by Scorim (shear controlled orientation in injection molding) under a wide range of processing windows. Tensile testing is performed and the corresponding performance related to the morphology evaluated by polarized light microscopy and scanning electron microscopy. The control of the processing parameters led to significant improvements of the tensile properties. Compounding by TSE and then processing by Scorim produces the maximum modulus of 7.4 GPa and the ductility as high as 19%, for the HA weight fraction of 30%. These mechanical properties match those of bone, and were obtained with much smaller amounts of HA reinforcement then has been previously reported in literature. Our PE + HA composites present the additional benefit of being ductile even for 50% HA amounts. The use Scorim is a unique way of inducing anisotropy to thick sections and to produce very stiff composites that may be used in biomedical applications with important mechanical loads. This fact, combined with the bioactive behavior of the HA phase, makes our composite usable for orthopedic load-bearing implants. (orig.)

Reis, R.L.; Cunha, A.M.; Oliveira, M.J.; Campos, A.R. [Dept. of Polymer Engineering, University of Minho, Guimaraes (Portugal); Bevis, M.J. [Wolfson Center for Materials Processing, Brunel Univ., Uxbridge (United Kingdom)

2001-04-01

318

Number representation is influenced by numerical processing level: an ERP study.  

Science.gov (United States)

The same numerical magnitude can be manifested in different physical notations. However, how the numbers with distinct notations are mentally represented is still unclear. Here, we hypothesized that how the number is mentally represented is influenced by the numerical processing level of the tasks. If the task only needed a low-level processing, the representation would be dependent on the surface forms of the numbers, exhibiting a numerical notation-dependent effect. By contrast, if the task required a deeper magnitude processing, the processing would utilize an abstract numerical format whose effects are notation independent. To test this hypothesis, we manipulated the notation type and the numerical processing level of the tasks. An ERP component N270 was taken to index the mismatch between the internal representation and the probed number. The results showed that N270 was enhanced when the magnitude was mismatched between two numbers. More importantly, under the task requiring a low-level processing (e.g., magnitude comparison), compared with the same notations, the latency of N270 difference wave was delayed by different notations, exhibiting a notation-dependent effect. However, in the task involving a deeper processing (e.g., magnitude addition), the N270 latencies were earlier for probes having distinct notations (Mandarin or Arabic number) than for probes having the same notations as in the addition operation (Mahjong). Moreover, no difference was found on N270 latencies between the two distinct notations but with similar degree of familiarity. Taken together, these results support our hypothesis that the numerical processing level affects the number representation. PMID:22252738

Liang, Junying; Yin, Jun; Chen, Tong; Chen, Hui; Ding, Xiaowei; Shen, Mowei

2012-04-01

319

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

320

Framework for sustainability assessment of industrial processes with multi-scale technology at design level: microcapsules production process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In a world with limited resources and serious environmental, social and economical impacts, a more sustainable life style is everyday more important. Therefore, the general objective of this work is to develop a methodological procedure for eco-efficiency and sustainability assessment of industrial processes with multi-scale technology at design level. The methodology developed follows the ISO 14040 series for environmental LCA standard. To integrate the three pillars of sustainability the an...

Navarro Rosa, Jennifer

2009-01-01

 
 
 
 
321

Modeling Sea-Level Change using Errors-in-Variables Integrated Gaussian Processes  

Science.gov (United States)

We perform Bayesian inference on historical and late Holocene (last 2000 years) rates of sea-level change. The data that form the input to our model are tide-gauge measurements and proxy reconstructions from cores of coastal sediment. To accurately estimate rates of sea-level change and reliably compare tide-gauge compilations with proxy reconstructions it is necessary to account for the uncertainties that characterize each dataset. Many previous studies used simple linear regression models (most commonly polynomial regression) resulting in overly precise rate estimates. The model we propose uses an integrated Gaussian process approach, where a Gaussian process prior is placed on the rate of sea-level change and the data itself is modeled as the integral of this rate process. The non-parametric Gaussian process model is known to be well suited to modeling time series data. The advantage of using an integrated Gaussian process is that it allows for the direct estimation of the derivative of a one dimensional curve. The derivative at a particular time point will be representative of the rate of sea level change at that time point. The tide gauge and proxy data are complicated by multiple sources of uncertainty, some of which arise as part of the data collection exercise. Most notably, the proxy reconstructions include temporal uncertainty from dating of the sediment core using techniques such as radiocarbon. As a result of this, the integrated Gaussian process model is set in an errors-in-variables (EIV) framework so as to take account of this temporal uncertainty. The data must be corrected for land-level change known as glacio-isostatic adjustment (GIA) as it is important to isolate the climate-related sea-level signal. The correction for GIA introduces covariance between individual age and sea level observations into the model. The proposed integrated Gaussian process model allows for the estimation of instantaneous rates of sea-level change and accounts for all available sources of uncertainty in tide-gauge and proxy-reconstruction data. Our response variable is sea level after correction for GIA. By embedding the integrated process in an errors-in-variables (EIV) framework, and removing the estimate of GIA, we can quantify rates with better estimates of uncertainty than previously possible. The model provides a flexible fit and enables us to estimate rates of change at any given time point, thus observing how rates have been evolving from the past to present day.

Cahill, Niamh; Parnell, Andrew; Kemp, Andrew; Horton, Benjamin

2014-05-01

322

Physical modeling of Fermi-level effects for decanano device process simulations  

International Nuclear Information System (INIS)

We report on a physically based Fermi-level modeling approach designed to be accurate and yet amenable to be implemented in a device-size process simulator. We use an atomistic kinetic Monte Carlo method in conjunction with a continuum treatment for carrier densities. The model includes: (i) charge reactions and electric bias according to the local Fermi-level; (ii) pairing and break-up reactions involving charged particles; (iii) clustering-related dopant deactivation; and (iv) Fermi level-dependent solubility. Degenerated statistics, band-gap narrowing, and damage-induced electrical compensation are also included. The parameters used for charged particles are in agreement with ab initio calculations and experimental results. This modeling scheme has proved to be very computationally efficient for realistic device-dimension process simulations. We present an illustrative set of simulation results for two common dopants, boron and arsenic, and discuss the potential of this approach for accurate process simulation of decanano CMOS devices

2004-12-15

323

Semi-empirical and process-based global sea level projections  

Science.gov (United States)

We review the two main approaches to estimating sea level rise over the coming century: physically plausible models of reduced complexity that exploit statistical relationships between sea level to climate forcing, and more complex physics-based models of the separate elements of the sea level budget. Recent estimates of sea level rise by 2100 have converged, but largely through increased contributions and uncertainty in process based model estimates of contributions from ice sheets. Hence here we focus on ice sheet flow as this has the largest potential to contribute to sea level rise. Recently, progress has been made in ice dynamics, ice stream flow, grounding line migration and integration of ice sheet models with high resolution climate models. Calving physics remains an important and difficult modeling issue. Mountain glaciers, numbering hundreds of thousands, must be modeled by extensive statistical extrapolation from a much smaller calibration dataset. Rugged topography creates problems in process-based mass balance simulations forced by regional climate models with resolutions 10-100 times larger than the glaciers. Semi-empirical models balance increasing numbers of parameters with the choice of noise model for the observations to avoid overfitting the highly autocorrelated sea level data. All models face difficulty in separating out non-climate driven sea level rise (e.g., groundwater extraction) and long term disequilibria in the present day cryosphere-sea level system

Moore, John; Grinsted, Aslak; Zwinger, Thomas; Jevrejeva, Svetlana

2013-04-01

324

Field-dependent magnetic parameters in {Ni4Mo12}: Magnetostriction at the molecular level?  

CERN Multimedia

We investigate the bulk magnetic, electron paramagnetic resonance, and magneto-optical properties of {Ni4Mo12}, a magnetic molecule with antiferromagnetically coupled tetrahedral {Ni4Mo12} in a diamagnetic molybdenum matrix. The low-temperature magnetization exhibits steps at irregular field intervals, a result that cannot be explained using a Heisenberg model even if it is augmented by magnetic anisotropy and biquadratic terms. Allowing the exchange and anisotropy parameters to depend on the magnetic field provides the best fit to our data, suggesting that the molecular structure (and thus the interactions between spins) may be changing with applied magnetic field.

Schnack, J; Luban, M; Koegerler, P; Morosan, E; Fuchs, R; Modler, R; Nojiri, H; Rai, R C; Cao, J; Musfeldt, J L; Xing Wei; Nojiri, Hiroyuki; Rai, Ram C.; Cao, Jinbo

2006-01-01

325

Detection of molecular surface adsorbates at the 10 -6 monolayer level and below  

Science.gov (United States)

Ultrathin molecular surface overlayers were deposited in an UHV chamber and were detected using pulsed infrared laser desorption followed by resonant laser post-ionization. A single-shot detection limit in the 10 -6 monolayer range was found for aniline adsorbed on silica, a system whose adsorption, laser desorption and ionization properties have been well studied. An excellent signal-to-noise ratio, as well as some simple modifications that will improve the detection efficiency suggest ultimate detection limits in the 10 -9 to 10 -10 ML range with this scheme.

Voumard, Pierre; Zhan, Qiao; Zenobi, Renato

1995-06-01

326

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

327

Coexistence of spinodal instability and thermal nucleation in thin-film rupture:Insights from molecular levels  

Energy Technology Data Exchange (ETDEWEB)

Despite extensive investigation using hydrodynamic models and experiments over the past decades, there remain open questions regarding the origin of the initial rupture of thin liquid films. One of the reasons that makes it difficult to identify the rupture origin is the coexistence of two dewettingmechanisms, namely, thermal nucleation and spinodal instability, as observed in many experimental studies. Using a coarse-grained model and large-scale molecular dynamics simulations, we are able to characterize the very early stage of dewetting in nanometer-thick liquid-metal films wetting a solid substrate. We observe the features characteristic of both spinodal instability and thermal nucleation in the spontaneously dewetting films and show that these two macroscopic mechanisms share a common origin at molecular levels.

Nguyen, Trung D [ORNL; Fuentes-Cabrera, Miguel A [ORNL; Fowlkes, Jason Davidson [ORNL; Rack, Philip D [ORNL

2014-01-01

328

Review process of PSA Level 2 of KBR. Concept and experience  

Energy Technology Data Exchange (ETDEWEB)

In Germany, a periodic safety review (PSR) has to be performed every 10 years by the utility. In the past, a PSR only included a plant-specific probabilistic safety analysis (PSA) Level 1 study. 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. 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. This paper will focus on conclusions and findings from a 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)' (Ministry of Social Affairs, Health, Family, Youth and Senior Citizens of Schleswig-Holstein) 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 between all parties involved on the major topics of the PSA Level 2 study. (orig.)

Andernacht, Martin [TUEV NORD SysTec GmbH und Co. KG, Hamburg (Germany); Glaser, Hendrik [Ministerium fuer Soziales, Gesundheit, Familie, Jugend un Senioren des Landes Schleswig-Holstein, Kiel (Germany). Dept. of Reactor Safety and Radiation Protection; Sonnenkalb, Martin [Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (GRS), Koeln (Germany). Dept. of Barrier Effectiveness

2009-01-15

329

Increase of neuronal response variability at higher processing levels as revealed by simultaneous recordings.  

Science.gov (United States)

A key problem for neuronal information processing is the variability of spike trains, something that is likely to constrain the encoding of sensory signals. We measured interspike-interval variability (coefficient of variation) as well as spike-count variability (Fano factor) in the metathoracic auditory system of locusts. We performed simultaneous intracellular recordings at the first three processing levels to establish identical physiological conditions. This allows us to assess whether variability is generated anew or is reduced during synaptic transmission and processing. Both the interspike-interval variability as well as the spike-count variability revealed similar trends and showed an increase from the periphery to higher processing levels. This result was confirmed by single-cell recordings. A comparison of ascending interneurons coding for sound direction and those encoding sound patterns showed that the latter respond more reliably to repeated stimulus presentations. In general, the variability of spiking responses was much lower than expected from a Poisson process. Furthermore, we observed a strong dependence of variability on the spike rate, which differed at the three levels investigated. The differences in spike rates account for most of the differences in variability observed between processing levels. For auditory receptors, we found a good agreement between the Fano factor and the squared coefficient of variation, suggesting similarities to a renewal process of spike generation at the periphery. At the level of interneurons, the Fano factor was lower than the squared coefficient of variation; this indicates a higher reliability than expected from the interspike-interval distribution. PMID:15716366

Vogel, A; Hennig, R M; Ronacher, B

2005-06-01

330

Regulating risk or risking regulation? Construal levels and depletion effects in the processing of health messages  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The depletion effect occurs when individuals who exert self-control in a previous task (i.e., depleted individuals) exhibit less self-control on a subsequent task relative to individuals who did not previously exert self-control. This article presents two experiments that implicate construal levels to understand the processes underlying depletion effects in the context of consumer health. At low-level construals, individuals rely on resource accessibility cues (e.g., feelings of tiredness) to...

Wan, Ew; Agrawal, N.

2009-01-01

331

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.

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

2013-01-01

332

Molecular dynamics studies of the process of amyloid aggregation of peptide fragments of transthyretin.  

Science.gov (United States)

It has been shown recently that an 11-residue peptide fragment of transthyretin, TTR(105-115), can form amyloid fibrils in vitro by adopting an extended beta-strand conformation. We used molecular dynamics simulations on systems of TTR(105-115) peptides, for a total length of about 5 micros, to explore the process of self-assembly and the structures of the resulting aggregates. Our results suggest that an antiparallel association of the beta-strands is more probable than a parallel one and that the central residues (T106-L111) in a beta-strand have a high propensity to form inter-peptide hydrogen bonds. The study of the dynamics of self-association indicated that, for this peptide, trajectories leading to conformations with high alpha-helical content are off-pathway from those leading to aggregates with high beta-structure content. We also show that the diverse oligomeric structures that form spontaneously in the molecular dynamics simulations are, to a large extent, compatible with solid-state NMR experimental measurements, including chemical shifts, on fully formed fibrils. The strategy that we present may therefore be used in the design of new experiments to determine the structure of amyloid fibrils, such as those involving site-specific isotope labelling schemes to measure key inter-atomic distances. PMID:15210354

Paci, Emanuele; Gsponer, Jörg; Salvatella, Xavier; Vendruscolo, Michele

2004-07-01

333

False memory and level of processing effect: an event-related potential study.  

Science.gov (United States)

Event-related potentials (ERPs) were used to determine the effects of level of processing on true and false memory, using the Deese-Roediger-McDermott (DRM) paradigm. In the DRM paradigm, lists of words highly associated to a single nonpresented word (the 'critical lure') are studied and, in a subsequent memory test, critical lures are often falsely remembered. Lists with three critical lures per list were auditorily presented here to participants who studied them with either a shallow (saying whether the word contained the letter 'o') or a deep (creating a mental image of the word) processing task. Visual presentation modality was used on a final recognition test. True recognition of studied words was significantly higher after deep encoding, whereas false recognition of nonpresented critical lures was similar in both experimental groups. At the ERP level, true and false recognition showed similar patterns: no FN400 effect was found, whereas comparable left parietal and late right frontal old/new effects were found for true and false recognition in both experimental conditions. Items studied under shallow encoding conditions elicited more positive ERP than items studied under deep encoding conditions at a 1000-1500 ms interval. These ERP results suggest that true and false recognition share some common underlying processes. Differential effects of level of processing on true and false memory were found only at the behavioral level but not at the ERP level. PMID:22811058

Beato, Maria Soledad; Boldini, Angela; Cadavid, Sara

2012-09-12

334

GOSAT three-years operation on orbit and updated Level-1 processing  

Science.gov (United States)

To monitor the global column concentration of carbon dioxide (CO2) and methane (CH4) from space, the Greenhouse gases Observing SATellite (GOSAT) was launched on January 23, 2009, and has started the operational observation. Thermal and Near Infrared Sensor for Carbon Observation- Fourier Transform Spectrometer (TANSO-FTS) has been continuously measuring CO2 and CH4 distributions globally every three days, and data distribution to the public started from Feb. 16, 2010. During three years operational periods, the radiometric, geometric and spectroscopic characterizations of TANSO have been continuously conducted with updating the Level-1 processing algorithm. To make a precise spectroscopic observation, correction algorithms were newly developed, demonstrated and installed on operational processing. Two major corrections are discussed. One is a correction of the scan-speed instability caused by micro-vibration from satellite. Through the on-orbit data analysis, degrading spectroscopic accuracy caused by periodically micro-vibrations was found, and these distortion effects were compensated with applying the re-sampling technique for interferogram. The other is non-linearity correction in the electronics. The main course of non-linearity is electronic filters on band 1 signal chain. The zero-level offset is slightly changed with input signal levels. To compensate the non-linear effect, the additional correction schemes are approved from recent version of Level-1 processing. In this presentation, the detail of on-orbit characteristics, processing algorithm of Level-1 and the current status of TANSO will be discussed.

Suto, H.; Kuze, A.; Shiomi, K.; Nakajima, M.

2012-04-01

335

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

336

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

337

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

1999-03-04

338

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

339

Solidification of low-level radioactive liquid waste using a cement-silicate process  

International Nuclear Information System (INIS)

Extensive use has been made of silicate and Portland cement for the solidification of industrial waste and recently this method has been successfully used to solidify a variety of low level radioactive wastes. The types of wastes processed to date include fuel fabrication sludges, power reactor waste, decontamination solution, and university laboratory waste. The cement-silicate process produces a stable solid with a minimal increase in volume and the chemicals are relatively inexpensive and readily available. The method is adaptable to either batch or continuous processing and the equipment is simple. The solid has leaching characteristics similar to or better than plain Portland cement mixtures and the leaching can be further reduced by the use of ion-exchange additives. The cement-silicate process has been used to solidify waste containing high levels of boric acid, oils, and organic solvents. The experience of handling the various types of liquid waste with a cement-silicate system is described

1979-05-01

340

On the use of a O2:SF6 plasma treatment on GaAs processed surfaces for molecular beam epitaxial regrowth  

International Nuclear Information System (INIS)

Preparation of processed GaAs surface cleaning in view of molecular beam epitaxy regrowth by means of a O2SF6 microwave plasma has been investigated. Photoemission, Auger electron spectroscopy, atomic force microscopy and secondary ion mass spectrometry have been used for characterization. The O2SF6 plasma treatment was found to be very efficient for decontaminating the GaAs surface and leads to the formation of an oxide layer that can be taken off by a thermal or low-temperature H-plasma-assisted deoxidation. The levels of oxygen and carbon contaminants at the regrowth interface were measured to be in the range of a standard homoepitaxial layer-epiready substrate interface. Fluorine was observed to be eliminated upon deoxidation while sulphur is present, particularly in the case of low temperature grown layers. This plasma treatment was found to be efficient for preparation of processed GaAs surfaces for molecular beam epitaxial regrowth.

2009-01-01

 
 
 
 
341

Visual information processing under time pressure in high and low level soccer players.  

Science.gov (United States)

The present study investigated differences in information processing rate of high and low level soccer players under three time-pressure conditions: High (0.5 sec.), Medium (1 sec.), and Low (2 sec.). No significant difference was found under Low time pressure, but under Medium time pressure the higher skilled group processed more visual information than the lower skilled group (p<.05). PMID:12831287

Zhongfan, Lu; Inomata, Kimihiro

2003-06-01

342

Many-body processes in atomic and molecular physics. Progress report  

International Nuclear Information System (INIS)

A proposal is presented for theoretical efforts towards the following projects: (1) carry out rotational predissociation lifetime calculations of several van der Waals molecules for which accurate potential energy surfaces were obtained recently by van der Waals molecular spectroscopic methods; (2) development and extension of the complex coordinate - coupled channel formalism to vibrational predissociation studies; (3) Floquet theory study of the quantum dynamics of multiphoton excitation of vibrational-rotational states of small molecules by laser light; (4) development and extension of the method of complex quasi-vibrational energy formalism to the study of intense field multiphoton dissociation of diatomic molecules and to photodissociation process in the presence of shape resonances; (5) investigation of the external field effects in multiphoton excitation and dissociation of small molecules. Depending on time and resources, several other projects may also be pursued. A detailed discussion covering these proposed projects is presented

1981-01-01

343

Molecular Dynamics Simulation of Sputtering Process of Hydrogen and Graphene Sheets  

CERN Multimedia

To clarify the yielding mechanism of small hydrocarbon molecules in chemical sputtering between hydrogen and graphene sheets, we made classical molecular dynamics simulation with modified Brenner's REBO potential which we proposed to deal with chemical reaction. As the simulation model, we prepared more realistic physical system, which is composed of 160 incident hydrogen atoms and ten graphene multilayers, than our previous model. From the present work, we found the following fact: breaking the covalent bonds between carbon atoms by hydrogen does not play an important role during destruction process of graphene structure, but momentum transfer from incident hydrogen to graphene causes to destroy graphene structure. Moreover, it is found that almost all fragments of graphene sheets form chain-shaped molecules, and that yielded hydrocarbon molecules are composed of carbon chain and single hydrogen-atom.

Nakamura, H; Nakamura, Hiroaki; Ito, Atsushi

2006-01-01

344

Auger electrons--a nanoprobe for structural, molecular and cellular processes.  

Science.gov (United States)

This paper provides a brief review of recently published work on biophysical and biological aspects of Auger processes. Three specific questions have been considered. (1) Does charge neutralisation contribute to molecular damage such as DNA strand breaks? (2) How many DNA double strand breaks are produced by a single decay of DNA bound (125)I? (3) What is the correlation between number of gammaH2AX foci and number of double strand breaks (DSB)? The paper also gives preliminary reports on two new calculations: (a) calculation of the spectrum of Auger electrons released during decay of (124)I and (b) the use of Auger electrons in the decay of (125)I as a probing agent of novel DNA structures. PMID:17132671

Nikjoo, H; Girard, P; Charlton, D E; Hofer, K G; Laughton, C A

2006-01-01

345

Molecular orbital study on the oxidation process of a beryllium atom in acidic solution  

International Nuclear Information System (INIS)

To elucidate the metal hydrolysis in acidic solution, the authors have studied the reaction of a Be atom (Be + 2H+ + aq --> Be2+aq + H2) with ab initio MO theory. The molecular process of the successive oxidation reaction of a Be atom (Be0-> BeI-> BeII) discussed. The author determined that the first stage of the oxidation is the water exchange reaction (H2O + [Be-HOH2]+ -> [H2OBeH]+ + H2O). The most possible species of BeI are [BeH(H2O)n]+ (n=1-3). In the second stage, the positively-charged hydrated BeI species can react with H3O+ to produce a hydrogen molecule and a hydrated Be2+ ion. The hydration of the reactant, transition state and product in every step plays an essential role in the reaction

1989-12-17

346

Molecular dynamics simulation of surface deformation via Ar+ ion collision process  

International Nuclear Information System (INIS)

We have carried out molecular dynamics (MD) simulations of 50 keV accelerated Ar ions, colliding with a Si surface. Using this procedure the amorphous structural region of the Si was found to expand with the progression of the interface region, that lie between the amorphous structure and the crystalline structure, as fluence increased in the depth direction. There has been considerable interest in studying the time development of the behavior of sputtered silicon atoms after being subjected to collisions with the Ar ions. Here, by tracking the atoms in the computational domain, clusters formed during sputtering are classified under various kinds. In this process small cluster of atoms e.g., monomer and dimer, and large cluster of atoms in forms of hillocks are formed where the smaller cluster have their energy higher than that of the large cluster.

2012-02-01

347

Masses and decay processes of strange, charmed and bottomed pentaquarks in the linear molecular heptaquark perspective  

CERN Document Server

In this paper the masses and decay processes of several new strange, charmed and bottomed exotic pentaquarks are predicted. Multiquarks are studied microscopically in a standard quark model. In pure ground-state pentaquarks the short-range interaction is computed and it is shown to be repulsive. The long-range and medium-range interactions are not expected to provide sufficient attraction. An additional quark-antiquark pair is then considered, and this is suggested to produce a narrow linear molecular system. The quarks assemble in three hadronic clusters, and the central hadron provides stability. The possible heptaquark hadrons with exotic pentaquark flavours, with any number of strange, charmed and bottomed quarks, are listed. I find that several new exotics may still be observed.

Bicudo, P J A

2004-01-01

348

Mapping variable ring polymer molecular dynamics: A path-integral based method for nonadiabatic processes  

Science.gov (United States)

We introduce mapping-variable ring polymer molecular dynamics (MV-RPMD), a model dynamics for the direct simulation of multi-electron processes. An extension of the RPMD idea, this method is based on an exact, imaginary time path-integral representation of the quantum Boltzmann operator using continuous Cartesian variables for both electronic states and nuclear degrees of freedom. We demonstrate the accuracy of the MV-RPMD approach in calculations of real-time, thermal correlation functions for a range of two-state single-mode model systems with different coupling strengths and asymmetries. Further, we show that the ensemble of classical trajectories employed in these simulations preserves the Boltzmann distribution and provides a direct probe into real-time coupling between electronic state transitions and nuclear dynamics.

Ananth, Nandini

2013-09-01

349

Mapping Variable Ring Polymer Molecular Dynamics: A Path-Integral Based Method for Nonadiabatic Processes  

CERN Document Server

We introduce mapping-variable ring polymer molecular dynamics (MV-RPMD), a model dynamics for the direct simulation of multi-electron processes. An extension of the RPMD idea, this method is based on an exact, imaginary time path-integral representation of the quantum Boltzmann operator using continuous Cartesian variables for both electronic states and nuclear degrees of freedom. We demonstrate the accuracy of the MV-RPMD approach in calculations of real-time, thermal correlation functions for a range of two-state single-mode model systems with different coupling strengths and asymmetries. Further, we show that the ensemble of classical trajectories employed in these simulations preserves the Boltzmann distribution and provides a direct probe into real-time coupling between electronic state transitions and nuclear dynamics.

Ananth, Nandini

2013-01-01

350

Donut-shaped chambers for analysis of biochemical processes at the cellular and subcellular levels.  

Science.gov (United States)

In order to study cell-cell variation with respect to enzymatic activity, individual live cell analysis should be complemented by measurement of single cell content in a biomimetic environment on a cellular scale arrangement. This is a challenging endeavor due to the small volume of a single cell, the low number of target molecules and cell motility. Micro-arrayed donut-shaped chambers (DSCs) of femtoliter (fL), picoliter (pL), and nanoliter (nL) volumes have been developed and produced for the analysis of biochemical reaction at the molecular, cellular and multicellular levels, respectively. DSCs are micro-arrayed, miniature vessels, in which each chamber acts as an individual isolated reaction compartment. Individual live cells can settle in the pL and nL DSCs, share the same space and be monitored under the microscope in a noninvasive, time-resolved manner. Following cell lysis and chamber sealing, invasive kinetic measurement based on cell content is achieved for the same individual cells. The fL chambers are used for the analysis of the same enzyme reaction at the molecular level. The various DSCs were used in this proof-of-principle work to analyze the reaction of intracellular esterase in both primary and cell line immune cell populations. These unique DSC arrays are easy to manufacture and offer an inexpensive and simple operating system for biochemical reaction measurement of numerous single cells used in various practical applications. PMID:24829933

Zurgil, N; Ravid-Hermesh, O; Shafran, Y; Howitz, S; Afrimzon, E; Sobolev, M; He, J; Shinar, E; Goldman-Levi, R; Deutsch, M

2014-07-01

351

Molecular Dynamics Simulations of the Roller Nanoimprint Process: Adhesion and Other Mechanical Characteristics  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Molecular dynamics simulations using tight-binding many body potential are carried out to study the roller imprint process of a gold single crystal. The effect of the roller tooth’s taper angle, imprint depth, imprint temperature, and imprint direction on the imprint force, adhesion, stress distribution, and strain are investigated. A two-stage roller imprint process was obtained from an imprint force curve. The two-stage imprint process included the imprint forming with a rapid increase of imprint force and the unloading stage combined with the adhesion stage. The results show that the imprint force and adhesion rapidly increase with decreasing taper angle and increasing imprint depth. The magnitude of the maximum imprint force and the time at which this maximum occurs are proportional to the imprint depth, but independent of the taper angle. In a comparison of the imprint mechanisms with a vertical imprint case, while high stress and strain regions are concentrated below the mold for vertical imprint, they also occur around the mold in the case of roller imprint. The regions were only concentrated on the substrate atoms underneath the mold in vertical imprint. Plastic flow increased with increasing imprint temperature.

Fang Te-Hua

2009-01-01

352

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

Energy Technology Data Exchange (ETDEWEB)

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.

Grantham, L.F.; McKisson, R.L.; De Wames, R.E.; Guon, J.; Flintoff, J.F.; McKenzie, D.E.

1983-01-01

353

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; Çak?r, Deniz; Brocks, Geert; Fahlman, Mats; Braun, Slawomir

2013-06-01

354

Molecular dynamics simulation of moderately coupled Yukawa liquids on graphics processing units  

International Nuclear Information System (INIS)

Complete text of publication follows. During the past decade Graphic Processing Unit (GPU) architectures have seen not only continuous performance increase, but a completely new horizon through general purpose computing as well. Thus, being integrated inside personal computers (PC), besides high-performance graphics applications, they provide a new platform for scientific computing, too, at moderate cost. Single instruction multiple data (SIMD) parallelism of GPUs is attractive for molecular simulations, as particle methods can largely be parallelized. We have developed a molecular dynamics (MD) simulation code for the NVIDIA Compute Unified Device Architecture (CUDA) GPU architecture that allows massive parallel computing, thereby permitting relatively big systems to be simulated on PC class computers, compared to the traditional Central Processing Unit (CPU) computations. We have carried out simulations of moderately coupled (01. ? ? ? 10) 3-dimensional Yukawa liquids [2], using particle numbers in the 105-106 range. Besides the MD simulations we have as well obtained pair correlation functions using the Hypernetted Chain (HNC) Approximation, and have compared the results with the GPU-MD data. The analysis of the asymptotic long-range behaviour of the pair correlation functions (transition between monotonic vs. oscillating decay) confirmed the results of [3]. Figure 1 shows pair correlation functions obtained from the numerical simulations and the theoretical HNC method, in which the bridge function was set to zero. We find a very good agreement between the curves at ?=0.1 and 1, over several orders of magnitude. The only difference seen at ? = 10 is the (expected) slightly higher correlation peak amplitude obtained from the MD simulation, compared to the HNC result. We thank OTKA for supporting this work (grant K77653) and Dr A. Archer for useful discussions.

2011-07-24

355

Management of high level radioactive aqueous effluents in advanced partitioning processes  

Energy Technology Data Exchange (ETDEWEB)

The context of this study is the development of management strategies for the high level radioactive aqueous effluents generated by advanced minor actinides partitioning processes. In the present nuclear reprocessing plants, high level liquid wastes are concentrated via successive evaporations, with or without de-nitration, to reach the inlet specifications of the downstream processing steps. In contrast to the PUREX process, effluents from advanced actinides partitioning processes contain large amounts of organic compounds (complexing agents, buffers or reducing reagents), which could disrupt concentration operations. Thus, in parallel with new partitioning process development, the compatibility of usual concentration operations with the high level liquid waste issued from them are investigated, and, if necessary, additional treatments to eliminate remaining organic compounds are reviewed. The behaviour of each reagent and related identified by-products is studied in laboratory-scale devices representative of industrial operating conditions. Final concentrated solutions (actinide or fission solutions) and the resulting distillates (i.e. decontaminated effluents) are checked in terms of compatibility with the downstream specifications. Process implementation and safety aspects are also evaluated. Kinetic and thermodynamic constants are measured. After the collection of these data, the effectiveness of the overall continuous process of the effluent treatment (combination of elementary operations) is evaluated through semi-empirical models which are also able to optimize the conditions for implementation. First results indicate that nitric acid streams containing complexing agents (oxalic acid, HEDTA, DTPA) will be managed by usual concentration processes, while buffered solutions ( containing glycolic, citric or malonic acid) will require additional treatments to lower organic carbon concentration. Oxidation process by hydrogen peroxide at boiling temperature has been shown to be very efficient as additional treatment in most cases. (authors)

Pochon, Patrick; Sans, Daniele; Lartigaud, Cathy; Bisel, Isabelle [Commissariat a l' Energie Atomique, Centre de Marcoule, BP 17171, Bagnols sur Ceze, 30207 (France)

2009-06-15

356

Tannin signatures of barks, needles, leaves, cones, and wood at the molecular level  

Science.gov (United States)

We analyzed 117 tissues from 77 different plant species for molecular tannin. Tannin was measured in 89 tissues (as high as 10.5 wt.% total tannin), including procyanidin (PC) tannin in 88 tissues, prodelphinidin (PD) tannin in 50, and propelargonidin (PP) tannin in 24. In addition to tannin, several flavones, flavanones, and triterpenoids were measured, the latter which yielded as much as 4.5 wt.%. Compositions varied considerably between species, including several that yielded comparatively rare tannin or triterpenoids. Conifer needles were distinguished by high yields of PD tannin overall and relative to PC tannin. Dicotyledon leaves were characterized by the presence of flavones and triterpenoids. Barks were marked by flavanones and tetracosanoic acid. Based on these trends, relationships that could be useful as geochemical parameters were developed for distinguishing needles, leaves, and barks as possible components of litter, soil, or sedimentary mixtures.

Hernes, Peter J.; Hedges, John I.

2004-03-01

357

Independent or integrated processing of interaural time and level differences in human auditory cortex?  

Science.gov (United States)

Sound localization in the horizontal plane is mainly determined by interaural time differences (ITD) and interaural level differences (ILD). Both cues result in an estimate of sound source location and in many real-life situations these two cues are roughly congruent. When stimulating listeners with headphones it is possible to counterbalance the two cues, so called ITD/ILD trading. This phenomenon speaks for integrated ITD/ILD processing at the behavioral level. However, it is unclear at what stages of the auditory processing stream ITD and ILD cues are integrated to provide a unified percept of sound lateralization. Therefore, we set out to test with human electroencephalography for integrated versus independent ITD/ILD processing at the level of preattentive cortical processing by measuring the mismatch negativity (MMN) to changes in sound lateralization. We presented a series of diotic standards (perceived at a midline position) that were interrupted by deviants that entailed either a change in a) ITD only, b) ILD only, c) congruent ITD and ILD, or d) counterbalanced ITD/ILD (ITD/ILD trading). The sound stimuli were either i) pure tones with a frequency of 500 Hz, or ii) amplitude modulated tones with a carrier frequency of 4000 Hz and a modulation frequency of 125 Hz. We observed significant MMN for the ITD/ILD traded deviants in case of the 500 Hz pure tones, and for the 4000 Hz amplitude-modulated tone. This speaks for independent processing of ITD and ILD at the level of the MMN within auditory cortex. However, the combined ITD/ILD cues elicited smaller MMN than the sum of the MMN induced in response to ITD and ILD cues presented in isolation for 500 Hz, but not 4000 Hz, suggesting independent processing for the higher frequency only. Thus, the two markers for independent processing - additivity and cue-conflict - resulted in contradicting conclusions with a dissociation between the lower (500 Hz) and higher frequency (4000 Hz) bands. PMID:24709274

Altmann, Christian F; Terada, Satoshi; Kashino, Makio; Goto, Kazuhiro; Mima, Tatsuya; Fukuyama, Hidenao; Furukawa, Shigeto

2014-06-01

358

Structural, Dynamic, and Electrostatic Properties of Fully Hydrated DMPC Bilayers From Molecular Dynamics Simulations Accelerated with Graphical Processing Units (GPUs)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present results of molecular dynamics simulations of fully hydrated DMPC bilayers performed on graphics processing units (GPUs) using current state-of-the-art non-polarizable force fields and a local GPU-enabled molecular dynamics code named FEN ZI. We treat the conditionally convergent electrostatic interaction energy exactly using the Particle Mesh Ewald method (PME) for solution of Poisson’s Equation for the electrostatic potential under periodic boundary conditions. We discuss elemen...

Ganesan, Narayan; Bauer, Brad A.; Lucas, Timothy R.; Patel, Sandeep; Taufer, Michela

2011-01-01

359

The crucial role of atomic and molecular processes in the success of controlled fusion  

International Nuclear Information System (INIS)

Atomic processes have played a key role in the success of the present and the next generation of magnetically and inertially confined controlled fusion experiments. Magnetic fusion experiments are beginning to access the plasma regimes needed for fusion reactors. Recent experiments on the TFTR tokamak at Princeton and the JET tokamak at Abingdon, UK, have produced fusion powers of 10-16 MW and temperatures in the 10 to 40 keV range. These achievements were made possible by impurity control and high power auxiliary heating, which both rely upon the successful utilization of atomic processes. Based on these and other experimental successes, in 1988 the US, Europe, Japan and Russia began participation in the International Thermonuclear Experimental Reactor project (ITER), with the goal of designing, constructing and operating a long pulse, ignited tokamak. The engineering design portion of the project will be completed in July 1998, and the ITER partners are now discussing an agreement for construction. Experiments on JT-60 U, JET, DIII-D, Alcator C-Mod, ASDEX Upgrade and other tokamaks together with computational models indicate that atomic processes can be used to reduce the peak heat fluxes on the wall to acceptable levels, control the impurity level, and minimize the impact of plasma disruptions in ITER. Two large stellarators, an alternative to the tokamak, are being built in Japan and Germany and control of atomic processes will be essential for their success. Comparable progress has also been made in Inertial Confinement Fusion. Experiments on NOVA, OMEGA, GEKKO XII and other laser facilities with both direct drive and indirect drive targets produce temperatures in the multi-keV range and capsule compression levels that scale to ignition for the National Ignition Facility (NIF) now under construction at the Lawrence Livermore National Laboratory. Atomic processes play a key role in the pellet compression and heating and are essential for diagnostics

1998-07-08

360

Chemical precipitation processes for the treatment of low and medium level liquid waste  

International Nuclear Information System (INIS)

Chemical precipitation processes for the treatment of various radioactive low and medium level liquid waste are described. Application to waste from reprocessing plants, removal of the main gamma emitters, actinide separation, utility liquid wastes generated during pwr operation, and combination of ultrafiltration with chemical precipitation, are all discussed. (U.K.)

1985-04-22

 
 
 
 
361

An innovative approach to solid Low Level Radioactive Waste processing and disposal  

International Nuclear Information System (INIS)

This paper will focus on a new system of Low Level Radioactive Waste (LLW) accumulation, processing and packaging, as-well as the implementation of a Laboratory-wide training program used to introduce new waste accumulation containers to all of the on-site radioactive waste generators, and to train them on the requirements of this innovative waste characterization and documentation program

1994-08-14

362

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

1993-04-26

363

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

364

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 interf...

Lindell, Linda; Cakir, Deniz; Brocks, Geert; Fahlman, Mats; Braun, Slawomir

2013-01-01

365

The calculation of second-order molecular properties at the configuration interaction level of accuracy  

International Nuclear Information System (INIS)

It is argued that the calculation of second-order properties, such as electric polarisabilities and magnetic susceptibilities, at both the Self-Consistent Field (SCF) and Configuration Interaction (CI) levels of accuracy, should be determined by perturbation theory rather than via the finite field approach. The SCF perturbation equations are discussed for both closed- and open-shell systems. Furthermore, to demonstrate the method, the first-order perturbation equations are solved at the CI level to give the electric polarisability tensor of water. (orig.)

1980-01-01

366

Simulation modeling of nuclear steam generator water level process--a case study  

Science.gov (United States)

Simulation modeling of the nuclear steam generator (SG) water level process in Qinshan Nuclear Power Plant (QNPP) is described in this paper. A practical methodology was adopted so that the model is both simple and accurate for control engineering implementation. The structure of the model is in the form of a transfer function, which was determined based on first-principles analysis and expert experience. The parameters of the model were obtained by taking advantage of the recorded historical response curves under the existing closed-loop control system. The results of process dimensional data verification and experimental tests demonstrate that the simulation model depicts the main dynamic characteristics of the SG water level process and is in accordance with the field recorded response curves. The model has been successfully applied to the design and test of an advanced digital feedwater control system in QNPP. PMID:10871210

Zhao; Ou; Du

2000-01-01

367

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 6H13/2-->6H15/2~3 ?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 6F9/2, 6H7/2 energy levels at 1125 nm and 6F11/2, 6H9/2 energy levels at 1358 nm established that the energy levels above the 6H11/2 level, excluding the 4F9/2 level, are entirely quenched by multiphonon emission in ZBLAN glass. The 6H11/2 and 6H13/2 energy levels emit luminescence with peaks at ~1700 and ~2880 nm, respectively, but at low quantum (luminescence) efficiencies. The quantum efficiency of the 6H11/2 level and 6H13/2 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 6H11/2 and 6H13/2 energy levels.

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

2010-03-01

368

Effectiveness of sensory processing strategies on activity level in inclusive preschool classrooms  

Directory of Open Access Journals (Sweden)

Full Text Available Chien-Lin Lin,1,2 Yu-Fan Min,3 Li-Wei Chou,1,2,* Chin-Kai Lin,4,* 1Department of Physical Medicine and Rehabilitation, China Medical University Hospital, Taichung, Taiwan; 2School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan; 3Faith, Hope and Love, Center for Children and Adults With Disabilities, Taichung, Taiwan; 4Program of Early Intervention, Department of Early Childhood Education, National Taichung University of Education, Taichung, Taiwan*These authors contributed equally to this workBackground: The purpose of this study was to investigate the effectiveness of sensory processing strategies in improving the activity level of children with sensory integration dysfunction.Methods: The study used a matching-only pretest–posttest control group design, which requires random matching of sensory integration dysfunction to the corresponding intervention group (n = 18 and control group (n = 18. The intervention group comprised 3–6-year-old children who received an 8-week school-day intervention during implementation of the theme curriculum.Results: The 8-week treatment significantly reduced the activity level and foot-swinging episodes in children with sensory integration dysfunction, and obtained a medium-effect size. However, the level of improvement in the control group did not show any statistically significant change.Conclusion: Sensory processing strategies could improve activity levels in children with sensory integration dysfunction. However, this study was unable to exclude a developmental effect. The social validity results show that sensory processing strategies can be integrated into the theme curriculum and improve activity levels in children.Keywords: activity level, preschool inclusive classroom, sensory integration dysfunction, sensory processing strategy

Lin CL

2012-10-01

369

Comparison of cryoconite organic matter composition from Arctic and Antarctic glaciers at the molecular-level  

Science.gov (United States)

Glacier surfaces are reservoirs that contain organic and inorganic debris referred to as cryoconite. Solar heating of this material results in the formation of water-filled depressions that are colonized by a variety of microbes and are hypothesized to play a role in carbon cycling in glacier ecosystems. Recent studies on cryoconite deposits have focused on their contribution to carbon fluxes to determine whether they are a net source or sink for atmospheric CO2. To better understand carbon cycling in these unique ecosystems, the molecular constituents of cryoconite organic matter (COM) require further elucidation. COM samples from four glaciers were analyzed by targeted extraction of plant- and microbial-derived biomarkers in conjunction with non-targeted NMR experiments to determine the COM composition and potential sources. Several molecular proxies were applied to assess COM degradation and microbial activity using samples from Greenland, the Canadian Arctic, and Antarctica. COM from Canadian (John Evans glacier) and Greenlandic (Leverett glacier) locations was more chemically heterogeneous than that from the Antarctic likely due to inputs from higher plants, mosses and Sphagnum as suggested by the solvent-extractable alkyl lipids and sterols and the detection of lignin- and Sphagnum-derived phenols after cupric oxide chemolysis. Solid-state 13C nuclear magnetic resonance (NMR) experiments highlighted the bulk chemical functional groups of COM allowing for a general assessment of its degradation stage from the alkyl/O-alkyl proxy whereas solution-state 1H NMR highlighted both microbial and plant contributions to base-soluble extracts from these COM samples. The dominance of 1H NMR signals from microbial protein/peptides in base-soluble extracts of COM from Antarctica (Joyce glacier and Garwood glacier), phospholipid fatty acid (PLFA) biomarker detection and the absence of plant-derived biomarkers in both the solvent and cupric oxide extracts suggests that this COM is dominated by microbial-derived material. These results indicate that COM carbon composition is dependent on the local glacier environment which may have a profound impact on carbon cycling and sequestration on glacier surfaces.

Pautler, Brent G.; Dubnick, Ashley; Sharp, Martin J.; Simpson, André J.; Simpson, Myrna J.

2013-03-01

370

The crystallization process of liquid vanadium studied by ab initio molecular dynamics  

Science.gov (United States)

We present a study of the crystallization process in liquid vanadium over a temperature range from 3000?K down to 1500?K using ab initio molecular dynamics simulations. Short-range order evolution during solidification is studied using various structural analysis methods. We show that the icosahedral-like short-range order is detected in the stable liquid phase and grows upon supercooling. The system undergoes a first-order phase transition (from a liquid to a solid state) at a temperature of about 1600?K. The crystal nucleation process is further studied using the time–temperature transformation mechanism by annealing the system at 1650?K. The nucleation is examined using bond-orientational order and density fluctuation analysis. Our finding is that various precursors appear in the region of high bond-orientational order with the majority having body-centered cubic (bcc)-like symmetry. This bcc-like region grows on annealing via thermal fluctuations. Our results reveal that the bond-orientational order precedes the density fluctuation, and is the main driving factor for nucleation.

Debela, T. T.; Wang, X. D.; Cao, Q. P.; Zhang, D. X.; Jiang, J. Z.

2014-04-01

371

Organic Semiconductors: A Molecular Picture of the Charge-Transport and Energy-Transport Processes.  

Science.gov (United States)

Conjugated organic oligomer and polymer materials are being increasingly considered for their incorporation as the active semiconductor elements in devices such as photo-voltaic cells, light-emitting diodes, or field-effects transistors. In the operation of these devices, electron-transfer and energy-transfer processes play a key role, for instance in the form of charge transport (in the bulk or across interfaces), energy transport, charge separation, or charge recombination [1]. Here, we provide a theoretical description of electron-transfer phenomena based on electron-transfer theory, which allows us to provide a molecular, chemically-oriented understanding. In this presentation, we focus on the parameters that impact the mobility of charge carriers [2], that is the electronic coupling within chains and between adjacent chains and the reorganization energy of the chains upon ionization. Materials under study include conjugated oligomers such as oligoacenes, oligothiophene-acenes, oligothiophenes, and oligothienacenes. [1] J.L. Br'edas, D. Beljonne, V. Coropceanu, and J. Cornil, ``Charge-Transfer and Energy-Transfer Processes in pi-Conjugated Oligomers and Polymers'', Chemical Reviews, 104, 4971-5004 (2004). [2] V. Coropceanu, J. Cornil, D.A. da Silva Filho, Y. Olivier, R. Silbey, and J.L. Br'edas, ``Charge Transport in Organic Semiconductors'', Chemical Reviews, 107, xxx (2007).

Brédas, Jean-Luc

2007-03-01

372

Questions surround DOE's program to process high-level radioactive waste while serious problems found with low-level waste disposal  

International Nuclear Information System (INIS)

This article addresses the General Accounting Office report criticizing the US DOE program to retrieve, process, immobilize, and store high-level radioactive waste until it can be moved to a permanent repository and discusses serious problems found with low-level waste disposal. The status of future repository at Yucca Mountain and current storage and processing at various sites is discussed

1990-01-18

373

Molecular-Level Variation Affects Population Growth in a Butterfly Metapopulation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Hanski, Ilkka; Saccheri, Ilik

2006-01-01

374

Atomic-level protein structure refinement using fragment-guided molecular dynamics conformation sampling.  

Science.gov (United States)

One of critical difficulties of molecular dynamics (MD) simulations in protein structure refinement is that the physics-based energy landscape lacks a middle-range funnel to guide nonnative conformations toward near-native states. We propose to use the target model as a probe to identify fragmental analogs from PDB. The distance maps are then used to reshape the MD energy funnel. The protocol was tested on 181 benchmarking and 26 CASP targets. It was found that structure models of correct folds with TM-score >0.5 can be often pulled closer to native with higher GDT-HA score, but improvement for the models of incorrect folds (TM-score <0.5) are much less pronounced. These data indicate that template-based fragmental distance maps essentially reshaped the MD energy landscape from golf-course-like to funnel-like ones in the successfully refined targets with a radius of TM-score ?0.5. These results demonstrate a new avenue to improve high-resolution structures by combining knowledge-based template information with physics-based MD simulations. PMID:22153501

Zhang, Jian; Liang, Yu; Zhang, Yang

2011-12-01

375

Understanding a transcriptional paradigm at the molecular level. The structure of yeast Gal80p.  

Science.gov (United States)

In yeast, the GAL genes encode the enzymes required for normal galactose metabolism. Regulation of these genes in response to the organism being challenged with galactose has served as a paradigm for eukaryotic transcriptional control over the last 50 years. Three proteins, the activator Gal4p, the repressor Gal80p, and the ligand sensor Gal3p, control the switch between inert and active gene expression. Gal80p, the focus of this investigation, plays a pivotal role both in terms of repressing the activity of Gal4p and allowing the GAL switch to respond to galactose. Here we present the three-dimensional structure of Gal80p from Kluyveromyces lactis and show that it is structurally homologous to glucose-fructose oxidoreductase, an enzyme in the sorbitol-gluconate pathway. Our results clearly define the overall tertiary and quaternary structure of Gal80p and suggest that Gal4p and Gal3p bind to Gal80p at distinct but overlapping sites. In addition to providing a molecular basis for previous biochemical and genetic studies, our structure demonstrates that much of the enzymatic scaffold of the oxidoreductase has been maintained in Gal80p, but it is utilized in a very different manner to facilitate transcriptional regulation. PMID:17121853

Thoden, James B; Sellick, Christopher A; Reece, Richard J; Holden, Hazel M

2007-01-19

376

Aquatic ecotoxicology: from the ecosystem to the cellular and molecular levels.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This review of aquatic ecotoxicology is presented in three parts. First, we discuss the fundamental concepts and stress the importance of its ecological basis and the complexity and diversity of the field of investigation, which result from actions and interactions between the physicochemical characteristics of the biotopes, the structural and functional properties of the living organisms, and the contamination modalities. Ecotoxicological mechanisms, regardless of the level of biological com...

Boudou, A.; Ribeyre, F.

1997-01-01

377

Molecular basis of high-level ciprofloxacin resistance in Neisseria gonorrhoeae strains from Shandong Province, China  

Directory of Open Access Journals (Sweden)

Full Text Available In the study, the ciprofloxacin resistance rate was 100%. High-level ciprofloxacin resistance rate was 63.55%. Sixteen different mutation patterns involved in the formation of ciprofloxacin resistance were identified. The most prevalent were patterns P7 (25.2%, P8 (15.0%, P9 (11.2%, P1 (10.3%, and P5 (10.3%. All of the 107 NG isolates analyzed for mutations in the study have demonstrated a change of Ser-91 ? Phe in the gyrA gene, and all except one have demonstrated a change in position 95 of the amino acid sequence. All of the 68 high-level QRNG isolates had double mutations in gyrA gene combined with a single or two mutations in parC gene. It is most important that a new mutation site of Ile-97 ? Met in gyrA and a new mutation of Leu-106 ? Ile in parC were found in the study, both leading to high-level ciprofloxacin resistance (MIC values, 8 µg/mL, 32 µg/mL, respectively. Therefore, we confim that gyrA mutations are necessary for the fluoroquinolone resistance phenotype and parC mutations are correlated intimately with high-level fluoroquinolone resistance. In China fluoroquinolone resistance in Neisseria gonorrhoeae strains is very serious and the new mutation sites in the fluoroquinolone resistance-determining regions emerge more and more quickly. Hence, in China fluoroquinolones, which are used to treat gonorrhoea presently, should be substituted by a new antibiotics.

L.H. Zhao

2013-01-01

378

Molecular aspects of high-level resistance to sulbactam-cefoperazone in Klebsiella oxytoca clinical isolates.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nine Klebsiella oxytoca strains which demonstrated resistance to the combination of sulbactam and cefoperazone were isolated from geographically separate hospitals in Japan in 1995. Among them, K. oxytoca SB23 showed high-level resistance to sulbactam-cefoperazone (MIC > 128 micrograms/ml) and aztreonam (MIC, 128 micrograms/ml). The sulbactam-cefoperazone resistance was not transferred from strain SB23 to Escherichia coli CSH2 by conjugation, beta-Lactamase RbiA, produced by strain SB23, was ...

Kimura, K.; Arakawa, Y.; Ohsuka, S.; Ito, H.; Suzuki, K.; Kurokawa, H.; Kato, N.; Ohta, M.

1996-01-01

379

Studying Molecular Interactions at the Single Bond Level with a Laminar Flow Chamber.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During the last decade, many investigators developed new methodologies allowing to study ligand-receptor interactions with unprecedented accuracy, up to the single bond level. Reported results include information on bond mechanical properties, association behaviour of surface-attached molecules, and dissection of energy landscapes and reaction pathways. The purpose of the present review is to discuss the potential and limitations of laminar flow chambers operated at low shear rates. This incl...

Bongrand, Pierre; Benoliel, Anne-marie; Pierres, Anne

2008-01-01

380

Real Time Implementation of Wiener Model PI (WMPI Controller in a Conical Tank Liquid Level Process  

Directory of Open Access Journals (Sweden)

Full Text Available Level control is very important for the successful operation of most chemical and biochemical industries since it is through the proper control of flows and levels that the desired production rates and inventories can be achieved. The aim of this study was the development and real time implementation of a Wiener Model based PI Controller (WMPIC for a conical tank level process. The conical tank level process exhibits severe static non-linear behavior and dynamic characteristics. Here, a WMPIC structure was developed by the way of compensating the process static non-linearity. Tuning rules suggested by PadmaSree-Srinivas-Chidambaram (2004 and Ziegler-Nichols (1942 were considered here for designing the controller. The real time implementation results of wiener model based PI controller were compared with those obtained using a conventional Linear PI Controller (LPIC. The performance of these controllers was analyzed in terms of Integral Square Error (ISE criterion. In addition to this, the robustness of the controllers was also analyzed.

P.K. Bhaba

2007-01-01

 
 
 
 
381

Energy Level Composite Curves-a new graphical methodology for the integration of energy intensive processes  

International Nuclear Information System (INIS)

Pinch Analysis, Exergy Analysis and Optimization have all been used independently or in combination for the energy integration of process plants. In order to address the issue of energy integration, taking into account composition and pressure effects, the concept of energy level as proposed by [X. Feng, X.X. Zhu, Combining pinch and exergy analysis for process modifications, Appl. Therm. Eng. 17 (1997) 249] has been modified and expanded in this work. We have developed a strategy for energy integration that uses process simulation tools to define the interaction between the various subsystems in the plant and a graphical technique to help the engineer interpret the results of the simulation with physical insights that point towards exploring possible integration schemes to increase energy efficiency. The proposed graphical representation of energy levels of processes is very similar to the Composite Curves of Pinch Analysis-the interpretation of the Energy Level Composite Curves reduces to the Pinch Analysis case when dealing with heat transfer. Other similarities and differences are detailed in this work. Energy integration of a methanol plant is taken as a case study to test the efficacy of this methodology. Potential integration schemes are identified that would have been difficult to visualize without the help of the new graphical representation

2006-09-01

382

Effects of storage and processing on residue levels of chlorpyrifos in soybeans.  

Science.gov (United States)

The residue levels of chlorpyrifos in soybeans during storage and processing were investigated. Soybeans were treated with chlorpyrifos aqueous solution and placed in a sealed plastic container. The residue of chlorpyrifos was determined in soybeans at six time points within 0 and 112days during storage and oil processing of the soybeans was conducted. The analysis of the residues of chlorpyrifos was carried out by gas chromatography-mass spectrometry (GC-MS). Results show that the dissipation of chlorpyrifos in soybeans is about 62% during the storage period. Moreover, the carryover of the residues from soybeans into oil is found to be related to the processing methods. Processing factor, which is defined as the ratio of chlorpyrifos residue concentration in oil sample to that in the soybean samples, was 11 and 0.25 after cold and hot pressing, respectively. PMID:24360437

Zhao, Liuwei; Ge, Jing; Liu, Fengmao; Jiang, Naiwen

2014-05-01

383

Determination of trans fatty acid levels by FTIR in processed foods in Australia.  

Science.gov (United States)

Health authorities around the world advise 'limiting consumption of trans fatty acid', however in Australia the trans fatty acid (TFA) content is not required to be listed in the nutrition information panel unless a declaration or nutrient claim is made about fatty acids or cholesterol. Since there is limited knowledge about trans fatty acid levels in processed foods available in Australia, this study aimed to determine the levels of TFA in selected food items known to be sources of TFA from previously published studies. Food items (n=92) that contain vegetable oil and a total fat content greater than 5% were included. This criterion was used in conjunction with a review of similar studies where food items were found to contain high levels of trans fatty acids. Lipids were extracted using solvents. Gravimetric methods were used to determine total fat content and trans fatty acid levels were quantified by Attenuated Total Reflectance Fourier Transform Infrared spectroscopy. High levels of trans fatty acids were found in certain items in the Australian food supply, with a high degree of variability. Of the samples analysed, 13 contained greater than 1 g of trans fatty acids per serving size, the highest value was 8.1 g/serving. Apart from when the nutrition information panel states that the content is less than a designated low level, food labels sold in Australia do not indicate trans fatty acid levels. We suggested that health authorities seek ways to assist consumers to limit their intakes of trans fatty acids. PMID:18818158

McCarthy, Justine; Barr, Daniel; Sinclair, Andrew

2008-01-01

384

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 re...

Hanski, Ilkka; Saccheri, Ilik

2006-01-01

385

Arginine and disordered amyloid-? peptide structures: molecular level insights into the toxicity in Alzheimer's disease.  

Science.gov (United States)

Recent studies present that the single arginine (R) residue in the sequence of A?42 adopts abundant ?-sheet structure and forms stable salt bridges with various residues. Furthermore, experiments proposed that R stimulates the A? assembly and arginine (R) to alanine (A) mutation (R5A) decreases both aggregate formation tendency and the degree of its toxicity. However, the exact roles of R and R5A mutation in the structures of A?42 are poorly understood. Extensive molecular dynamics simulations along with thermodynamic calculations present that R5A mutation impacts the structures and free energy landscapes of the aqueous A?42 peptide. The ?-sheet structure almost disappears in the Ala21-Ala30 region but is more abundant in parts of the central hydrophobic core and C-terminal regions of A?42 upon R5A mutation. More abundant ?-helix is adopted in parts of the N-terminal and mid-domain regions and less prominent ?-helix formation occurs in the central hydrophobic core region of A?42 upon R5A mutation. Interestingly, intramolecular interactions between N- and C-terminal or mid-domain regions disappear upon R5A mutation. The structures of A?42 are thermodynamically less stable and retain reduced compactness upon R5A mutation. R5A mutant-type structure stability increases with more prominent central hydrophobic core and mid-domain or C-terminal region interactions. Based on our results reported in this work, small organic molecules and antibodies that avoid ?-sheet formation in the Ala21-Ala30 region and hinder the intramolecular interactions occurring between the N-terminal and mid-domain or C-terminal regions of A?42 may help to reduce A?42 toxicity in Alzheimer's disease. PMID:24041422

Coskuner, Orkid; Wise-Scira, Olivia

2013-12-18

386

Mineralization of the connective tissue: a complex molecular process leading to age-related loss of function.  

Science.gov (United States)

Abstract Age-related metastatic mineralization of soft tissues has been considered a passive and spontaneous process. Recent data have demonstrated that calcium salt deposition in soft tissues could be a highly regulated process. Although calcification occurs in any tissue type, vascular calcification has been of particular interest due to association with atherosclerosis, chronic kidney disease (CKD), and osteoporosis. Different mechanisms underlying calcium apatite accumulation are explored with these age-related disorders. In the case of atherosclerotic plaques, oxy-lipids trigger release of the pro-inflammatory cytokines and inflammation that activate calcification processes in aorta intimae. In CKD patients, renal failure alters the balance between calcium and phosphate levels usually regulated by fibroblast growth factor-23 (FGF23), Klotho, and vitamin D, and vascular smooth muscle cells (VSMCs) begin to explore an osteoblastosteoblast-like phenotype. Calcification could affect extracellular matrix along with VSMCs. Collagen is a major component of extracellular matrix and its modifications accumulate with age. The formation of cross-links between collagen fibers is regulated by the action of lysine hydroxylases and lysyl oxidase and could occur spontaneously. Oxidation-induced advanced glycation end products (AGEs) are a major type of spontaneous cross-links that accelerate with age and may result in tissue stiffness, problems with recycling, and potential accumulation of calcium apatite. Applying strategies for clearing the AGEs proposed by de Grey may be more difficult in the highly mineralized extracellular matrix. We performed bioinformatic analysis of the molecular pathways underlying calcification in atherosclerotic and CKD patients, signaling pathways of collagen cross-links formation, and bone mineralization, and we propose new potential targets and review drugs for calcification treatment. PMID:23902273

Shindyapina, Anastasia V; Mkrtchyan, Garik V; Gneteeva, Tatiana; Buiucli, Sveatoslav; Tancowny, B; Kulka, M; Aliper, Alexander; Zhavoronkov, Alexander

2014-04-01

387

Serum levels of CEA and CA15-3 in different molecular subtypes and prognostic value in Chinese breast cancer.  

Science.gov (United States)

The prognostic significance of preoperative carcinoembryonic antigen (CEA) and cancer antigen 15-3 (CA15-3) levels in breast cancer is controversial. This study evaluated the prognostic value of preoperative serum CEA and CA15-3 levels in Chinese breast cancer patients. A total of 470 patients with breast cancer had preoperative CEA and CA15-3 concentrations measured. The relationships between preoperative concentration and clinicopathological factors and outcomes were determined. CEA and CA15-3 levels were increased in 34 (7.2%) and 58 (12.3%) patients, respectively. Elevations of serum CEA and CA-15-3 levels correlated with the primary tumor size and axillary lymph node status. CEA levels were lower in patients with triple-negative breast cancer than in those with other subtypes (P = 0.002). The 5-year distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) of CEA-negative vs. CEA-positive patients were 84.1% vs. 54.5% (P DMFS, DFS, and OS of CA15-3-negative vs. CA15-3-positive patients were 84.0% vs. 69.6% (P = 0.002), 83.0% vs. 66.2% (P DMFS (P = 0.021) and DFS (P = 0.032), and DFS (P = 0.014) and OS (P = 0.032), respectively. Serum levels of CEA and CA15-3 may differ in breast cancer molecular subtypes and preoperative levels of CEA and CA15-3 have a significant effect on prognosis in Chinese women with breast cancer. PMID:24291374

Wu, San-gang; He, Zhen-yu; Zhou, Juan; Sun, Jia-yuan; Li, Feng-yan; Lin, Qin; Guo, Ling; Lin, Huan-xin

2014-02-01

388

Region based route planning - Multi-abstraction route planning based on intermediate level vision processing  

Science.gov (United States)

Intermediate and high level processing operations are performed on vision data for the organization of images into more meaningful, higher-level topological representations by means of a region-based route planner (RBRP). The RBRP operates in terrain scenarios where some or most of th