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1

Devices for collecting chemical compounds  

DOEpatents

A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from a fixed surface so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

Scott, Jill R; Groenewold, Gary S

2013-12-24

2

Collected Reprints-1969 Volume Ii.  

National Technical Information Service (NTIS)

The report is a collection of reprints from ESSA Institute of oceanography, Atlantic and Pacific oceanographic laboratories, that includes marine geophysics and geology, marine meteorology, physical oceanography, as well as general reports in oceanography...

1970-01-01

3

World War II Poster Collection  

NSDL National Science Digital Library

The Government Publications Department of the Northwestern University Library provides this browsable and searchable image base of over 200 posters related to World War II. Several powerful search options are available (especially in the advanced search mode, which supports numerous Boolean, truncation, and proximity operators, as well as field searching on ten separate fields). In addition, posters can be browsed by date, title, or topic (unfortunately, topics are not separately delineated at this time). Each retrieved poster is accompanied by a full cataloged record that includes artist, title, publisher, date, format, and a short caption, among other items. Clicking on the thumbnail image enlarges the image. The Library intends to make all of its over 300 posters available at this site.

1998-01-01

4

The ISLSCP Initiative II Data Collection  

NASA Astrophysics Data System (ADS)

The International Satellite Land Surface Climatology Project (ISLSCP) sponsored the production of the first, co-registered, peer-reviewed, documented interdisciplinary data collection that included global, monthly surface meteorology, vegetation, soils, surface routing and runoff, atmospheric radiation data and clouds for 1987 and 1988 at a 1-degree spatial resolution. The ISLSCP Initiative II collection is greatly expanded in both time and spatial resolution. Initiative II is a 10-year core global data collection spanning the years 1987 to 1995 with improved spatial and temporal resolution (one-quarter to 1 degree) using improved data generation algorithms. In addition, Initiative II includes some data sets spanning the 18-year period, 1982-1999. The data collection includes additional carbon and socioeconomic data sets uniquely designed to support global carbon cycling studies. Initiative II provides a comprehensive collection of high priority global data sets in a consistent data format and Earth projection. The full Initiative II collection consists of some 47 different data types with 230 different parameters shown below (number of parameters in parentheses). Radiation and Clouds (45) Hydrology, Topography and Soils (39) Near-Surface Meteorology (95) Vegetation (29) Fixed (11) Carbon (15) Monthly (12) Snow and Sea Ice (4) Monthly 3-hourly (44) Oceans (1) 3-hourly (28) Socioeconomic (2) Each of the 47 data sets and accompanying documents have undergone two peer reviews, one by reviewers familiar with the data set (but not the producer of it) and a second reviewer, a potential user who has no previous experience with it. The data set draft is complete and is to be followed by an evaluation of the entire collection prior to final publication by the Initiative II staff and external users. This collection-overview evaluation will include an assessment of the individual data series against each other and independent data sources and an evaluation of the value of the ISLSCP II collection as a whole.The Initiative II collection is available at http://islscp2.sesda.com/.

Hall, F. G.

2004-12-01

5

Type I and II ?-turns prediction using NMR chemical shifts.  

PubMed

A method for predicting type I and II ?-turns using nuclear magnetic resonance (NMR) chemical shifts is proposed. Isolated ?-turn chemical-shift data were collected from 1,798 protein chains. One-dimensional statistical analyses on chemical-shift data of three classes ?-turn (type I, II, and VIII) showed different distributions at four positions, (i) to (i + 3). Considering the central two residues of type I ?-turns, the mean values of C?, C?, HN, and NH chemical shifts were generally (i + 1) > (i + 2). The mean values of C? and H? chemical shifts were (i + 1) < (i + 2). The distributions of the central two residues in type II and VIII ?-turns were also distinguishable by trends of chemical shift values. Two-dimensional cluster analyses on chemical-shift data show positional distributions more clearly. Based on these propensities of chemical shift classified as a function of position, rules were derived using scoring matrices for four consecutive residues to predict type I and II ?-turns. The proposed method achieves an overall prediction accuracy of 83.2 and 84.2 % with the Matthews correlation coefficient values of 0.317 and 0.632 for type I and II ?-turns, indicating that its higher accuracy for type II turn prediction. The results show that it is feasible to use NMR chemical shifts to predict the ?-turn types in proteins. The proposed method can be incorporated into other chemical-shift based protein secondary structure prediction methods. PMID:24838372

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

2014-07-01

6

Collective Surfing of Chemically Active Particles  

NASA Astrophysics Data System (ADS)

We study theoretically the collective dynamics of immotile particles bound to a 2D surface atop a 3D fluid layer. These particles are chemically active and produce a chemical concentration field that creates surface-tension gradients along the surface. The resultant Marangoni stresses create flows that carry the particles, possibly concentrating them. For a 3D diffusion-dominated concentration field and Stokesian fluid we show that the surface dynamics of active particle density can be determined using nonlocal 2D surface operators. Remarkably, we also show that for both deep or shallow fluid layers this surface dynamics reduces to the 2D Keller-Segel model for the collective chemotactic aggregation of slime mold colonies. Mathematical analysis has established that the Keller-Segel model can yield finite-time, finite-mass concentration singularities. We show that such singular behavior occurs in our finite-depth system, and study the associated 3D flow structures.

Masoud, Hassan; Shelley, Michael J.

2014-03-01

7

Collective surfing of chemically active particles.  

PubMed

We study theoretically the collective dynamics of immotile particles bound to a 2D surface atop a 3D fluid layer. These particles are chemically active and produce a chemical concentration field that creates surface-tension gradients along the surface. The resultant Marangoni stresses create flows that carry the particles, possibly concentrating them. For a 3D diffusion-dominated concentration field and Stokesian fluid we show that the surface dynamics of active particle density can be determined using nonlocal 2D surface operators. Remarkably, we also show that for both deep or shallow fluid layers this surface dynamics reduces to the 2D Keller-Segel model for the collective chemotactic aggregation of slime mold colonies. Mathematical analysis has established that the Keller-Segel model can yield finite-time, finite-mass concentration singularities. We show that such singular behavior occurs in our finite-depth system, and study the associated 3D flow structures. PMID:24724685

Masoud, Hassan; Shelley, Michael J

2014-03-28

8

World War I and II Poster Collection  

NSDL National Science Digital Library

War posters from World War I and II encouraged the people of the nations at war to buy war bonds, plant gardens, ration, enlist, or work extra hard for the sake of the war effort. A collection of these posters can be found in abundance on the library website of the University of North Texas. The library has over 600 war posters, and fortunately, 493 of them are digitized. Some are quaint by today's standards, but some, like the fifth record on the homepage, entitled "Deliver Us From Evil: Buy War Bonds," has an eerie haunting quality to it. In the search box underneath the introduction to the poster collection, type in Geisel to see a poster by a familiar artist and author, encouraging Americans to "Starve the Squander Bug." Visitors should click on the thumbnail to see those "squander bugs" in full detail.

9

COLLECTION OF SULFUR GASES WITH CHEMICALLY-TREATED FILTERS  

EPA Science Inventory

Chemically treated membrane filters were evaluated to collect hydrogen sulfide and sulfur dioxide. Four chemical treatments were tested. Silver nitrate and silver nitrate-tartaric acid filters were used to collect hydrogen sulfide, and lithium hydroxide and potassium bicarbonate ...

10

75 FR 36067 - Agency Information Collection Activities; Proposed Collection; Comment Request; Chemical-Specific...  

Federal Register 2010, 2011, 2012, 2013

...Chemical-Specific Rules, TSCA Section 8(a); EPA ICR No. 1198.09, OMB Control No. 2070-0067...approved Information Collection Request (ICR) to the Office of Management and Budget (OMB). This ICR, entitled: ``Chemical-Specific...

2010-06-24

11

Device for collecting chemical compounds and related methods  

DOEpatents

A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from the fixed surfaces so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

Scott, Jill R.; Groenewold, Gary S.; Rae, Catherine

2013-01-01

12

COLLECTIVE EFFECTS IN THE NSLS-II STORAGE RING.  

SciTech Connect

A new high-brightness synchrotron light source (NSLS-II) is under design at BNL. The 3-GeV NSLS-II storage ring has a double-bend achromatic lattice with damping wigglers installed in zero-dispersion straights to reduce the emittance below 1nm. In this paper, we present an overview of the impact of collective effects upon the performance of the storage ring. Subjects discussed include instability thresholds, Touschek lifetime and intra-beam scattering.

KRINSKY,S.; BENGTSSON, J.; BERG, J.S.; BLASKIEWICZ, M.; BLEDNYKH, A.; GUO, W.; MALITSKY, N.; MONTAG, C.; PODOBEDOV, B.; ROSE, J.; TOWNE, N.; YU, L.H.

2007-06-25

13

Collection and chemical analysis of lichens for biomonitoring. Book chapter  

SciTech Connect

The chapter discusses the interrelated aspects of biomonitoring using chemical analysis of lichens. Many unique aspects of study objectives, study design (including design tasks, considerations, and sampling schemes), sample collection, sample preparation, and sample analysis that are required for a successful biomonitoring program using chemical analysis are emphasized. The advantages and disadvantages of common analytical methods suitable for chemical analysis of lichens are briefly discussed. Aspects of a quality assurance program and final contract reports are highlighted. In addition, some examples of studies using chemical analysis of lichens are discussed.

Jackson, L.L.; Ford, J.; Schwartzman, D.

1991-01-01

14

Summary of Phase II Regulations: National Primary Drinking Water Regulation for 38 Inorganic and Synthetic Organic Chemicals.  

National Technical Information Service (NTIS)

The U.S. Environmental Protection Agency promulgated National Primary Drinking Water Regulations for 38 inorganic and synthetic organic chemicals on January 30, 1991 and July 1, 1991. Collectively, these two rulemakings are referred to as the Phase II Rul...

A. Havinga

1991-01-01

15

Strippable coatings for forensic collection of trace chemicals from surfaces.  

PubMed

Surface sampling for chemical analysis plays a vital role in applications like environmental monitoring, industrial hygiene, homeland security, and forensics. The standard surface sampling tool is a simple cotton gauze pad, but as techniques become more sensitive and the variety of analytes increases, gauze is failing to meet the needs of the community. Here, the collection of eight small molecules from glass surfaces with three different commercial spray-on, strippable coatings was demonstrated and their collection efficiency, as measured by gas chromatography/mass spectrometry, was compared to that of a standard cotton gauze. The three coating systems recovered 87-95% of the each compound, on average, from a nominal initial surface coverage of 0.1 g/m(2) per analyte. These recoveries were 3-fold better than the cotton gauze which had an average collection efficiency of 31%. PMID:23157576

Beltis, Kevin J; Drennan, Paul M; Jakubowski, Michael J; Pindzola, Bradford A

2012-12-18

16

Chemical Composition of Wild-2 Dust Collected by Stardust  

NASA Astrophysics Data System (ADS)

The Stardust spacecraft collected dust from Comet Wild-2 in two forms: material distributed along tracks in aerogel capture cells and residue in impact craters. To analyze the chemical composition of these samples the tracks produced in the aerogel were extracted as keystones containing complete tracks. Twenty-six tracks were analyzed using an X-Ray Microprobe, providing x-ray fluorescence chemical analysis for elements having K-lines at energies high enough to permit escape from the overlying aerogel (S and the heavier elements, including the moderately-volatile trace elements Cu, Zn, and Ga). Two of these tracks were then split open, exposing the interior for analysis by TOF-SIMS (which allowed detection of the lighter elements, e.g., Mg and Al). Neither Si nor O could be determined for samples captured in the aerogel, since these are the major elements in the aerogel itself. The residue in craters in the Al-foil were analyzed by SEM-EDX and TOF-SIMS. The crater residues provide information on the important light elements (Mg and Si). By combining the results from the craters and the tracks, a comprehensive chemical analysis of the Wild-2 dust was possible. Preliminary Examination of the material indicates that: 1) For particles collected in the aerogel, a significant fraction of the incident mass is frequently deposited along the entry track, suggesting the individual Wild-2 dust particles that hit the aerogel were relatively weak aggregates. 2) The chemical composition of the terminal particle in the track is frequently significantly different from the composition of the material deposited along the track, 3) Most of the elements measured show variations in their Fe-normalized abundances of more than two orders-of-magnitude in both the terminal particles and the material deposited along track walls, indicating that the Wild-2 dust is compositionally heterogeneous at the size scale of the largest particles analyzed, not simply a well-mixed aggregate of sub-micron grains, 4) The mean content of the refractory, rock-forming elements (Mg, Ca, Si, Cr, Fe, and Ni) averaged over the whole tracks and/or the crater residues in the Wild-2 grains are approximately chondritic, and, 5) There is an apparent enrichment over CI in some of the moderately-volatile minor elements (Cu, Zn, and Ga) in the Wild-2 dust.

Flynn, G. J.

2006-12-01

17

75 FR 68370 - Agency Information Collection Activities: Office of Infrastructure Protection; Chemical Security...  

Federal Register 2010, 2011, 2012, 2013

...OF HOMELAND SECURITY National Protection...DHS-2010-0071] Agency Information Collection Activities...Protection; Chemical Security Awareness Training Program...currently approved information collection request...the Chemical Security Awareness Training...

2010-11-05

18

Improved Devices for Collecting Sweat for Chemical Analysis  

NASA Technical Reports Server (NTRS)

Improved devices have been proposed for collecting sweat for biochemical analysis - especially for determination of the concentration of Ca2+ ions in sweat as a measure of loss of Ca from bones. Unlike commercially available sweat-collection patches used previously in monitoring osteoporosis and in qualitative screening for some drugs, the proposed devices would not allow evaporation of the volatile chemical components (mostly water) of sweat. Moreover, the proposed devices would be designed to enable determination of the volumes of collected sweat. From these volumes and the quantities of Ca(2+) and/or other analytes as determined by other means summarized below, one could determine the concentrations of the analytes in sweat. A device according to the proposal would be flexible and would be worn like a commercial sweat-collection patch. It would be made of molded polydimethylsiloxane (silicone rubber) or other suitable material having properties that, for the purpose of analyzing sweat, are similar to those of glass. The die for molding the silicone rubber would be fabricated by a combination of lithography and electroplating. The die would reproducibly form, in the silicone rubber, a precisely defined number of capillary channels per unit area, each channel having a precisely defined volume. Optionally, electrodes for measuring the Ca(2+) content of the sweat could be incorporated into the device. The volume of sweat collected in the capillary channels of the device would be determined from (1) the amount of light or radio waves of a given wavelength absorbed by the device and (2) the known geometry of the array of capillary channels. Then, in one of two options, centrifugation would be performed to move the sweat from the capillary tubes to the region containing the electrodes, which would be used to measure the Ca(2+) content by a standard technique. In the other option, centrifugation would be performed to remove the sweat from the device to make the sweat available to other analytical instruments for measuring concentrations of substances other than Ca(2+).

Feedback, Daniel L.; Clarke, Mark S. F.

2011-01-01

19

Improved Devices for Collecting Sweat for Chemical Analysis  

NASA Technical Reports Server (NTRS)

Improved devices have been proposed for collecting sweat for biochemical analysis especially for determination of the concentration of Ca2+ ions in sweat as a measure of loss of Ca from bones. Unlike commercially available sweat-collection patches used previously in monitoring osteoporosis and in qualitative screening for some drugs, the proposed devices would not allow evaporation of the volatile chemical components (mostly water) of sweat. Moreover, the proposed devices would be designed to enable determination of the volumes of collected sweat. From these volumes and the quantities of Ca2+ and/or other analytes as determined by other means summarized below, one could determine the concentrations of the analytes in sweat. A device according to the proposal would be flexible and would be worn like a commercial sweat-collection patch. It would be made of molded polydimethylsiloxane (silicone rubber) or other suitable material having properties that, for the purpose of analyzing sweat, are similar to those of glass. The die for molding the silicone rubber would be fabricated by a combination of lithography and electroplating. The die would reproducibly form, in the silicone rubber, a precisely defined number of capillary channels per unit area, each channel having a precisely defined volume. Optionally, electrodes for measuring the Ca2+ content of the sweat could be incorporated into the device. The volume of sweat collected in the capillary channels of the device would be determined from (1) the amount of light or radio waves of a given wavelength absorbed by the device and (2) the known geometry of the array of capillary channels. Then, in one of two options, centrifugation would be performed to move the sweat from the capillary tubes to the region containing the electrodes, which would be used to measure the Ca2+ content by a standard technique. In the other option, centrifugation would be performed to remove the sweat from the device to make the sweat available to other analytical instruments for measuring concentrations of substances other than Ca2+.

Feeback, Daniel L.; Clarke, Mark S. F.

2011-01-01

20

77 FR 22559 - Proposed Information Collection; Comment Request; Chemical Weapons Convention Provisions of the...  

Federal Register 2010, 2011, 2012, 2013

...Collection; Comment Request; Chemical Weapons Convention Provisions of the Export Administration...INFORMATION: I. Abstract The Chemical Weapons Convention (CWC) is a multilateral arms...achieve an international ban on chemical weapons (CW). The CWC prohibits the use,...

2012-04-16

21

Chemical analysis of rain samples collected over the Pacific Ocean  

NASA Astrophysics Data System (ADS)

During seven research cruises in the Pacific Ocean from 1984 to 1989 we collected rain samples for chemical analyses. The geographical and temporal variations of rain chemistry were studied in relation to natural and anthropogenic sources and transport of the constituents. The pH values of rain samples ranged from 3.9 to 7.2, with a mean of 5.6 (n = 104, ? = 0.5). The most acidic rain was found near the big ports, where SO4= and NO3- concentrations in rain were also the highest. The data indicated that wet deposition transports anthropogenic pollution from continents to oceans. Enrichments of Ca++ and K+, which are compared to Na+ in seawater, were observed in all rain samples throughout the ocean. However, their enrichment factors (EF) decrease with distance from land, signifying the extent of transport of crustal elements through cloud process and wet deposition. The EFs of Mg++ were close to unity, indicating its common origin with Na+. The EFs of Cl- in most rain samples were less than l, indicating loss of Cl- in aerosols, cloud droplets, or rain drops. High EFs of SO4= were also observed at the equatorial regions, where biogenic production of dimethyl sulfide is well known. During the 1987 El Niño anomaly the sulfate aerosol distribution and rainfall patterns altered with air trajectories. The effects of sulfate aerosol on cloud condensation and rainfall amount in various regions during normal years and the El Niño anomaly are discussed.

Nagamoto, C.; Parungo, F.; Kopcewicz, B.; Zhou, M. Y.

1990-12-01

22

Nanosized and Nanostructured II-VI Semiconductors: Chemical Sensor Applications  

NASA Astrophysics Data System (ADS)

Principles of chemical sensing are considered and examples from the literature of chemical sensors including II-VI semiconductor nanomaterials are given. A new method for improving the discrimination of semiconductor thin-film gas sensors is introduced, which uses the amplitude and phase of the photocurrent response to a modulated light source. Preparation of nanocrystalline CdS and CdSe thin films of various thicknesses (30-200 nm) by physical vapour deposition is described. Data from room temperature studies of the effect of exposure to a set of vapours (water, ethanol, ammonia, acetone) on the film resistance and quartz-crystal microbalance frequency are presented.

Nesheva, Diana

23

PWR steam generator chemical cleaning. Phase II. Final report  

SciTech Connect

Two techniques believed capable of chemically dissolving the corrosion products in the annuli between tubes and support plates were developed in laboratory work in Phase I of this project and were pilot tested in Indian Point Unit No. 1 steam generators. In Phase II, one of the techniques was shown to be inadequate on an actual sample taken from an Indian Point Unit No. 2 steam generator. The other technique was modified slightly, and it was demonstrated that the tube/support plate annulus could be chemically cleaned effectively.

Not Available

1980-01-01

24

Arthur Paul Afghanistan Collection Bibliography - Volume II: English and European Languages (2000)  

Microsoft Academic Search

In December 1995, the first volume of this bibliography was published. Volume I included all the Pashto and Dari language titles that were in the Arthur Paul Afghanistan Collection at that time. Volume II includes English and European language materials. This volume contains titles that were added to the Collection prior to January 1998.\\u000aThe Arthur Paul Afghanistan Collection is

Shaista Wahab

2000-01-01

25

REIS: Phase II, Report IV: REIS Data Collection Procedures.  

National Technical Information Service (NTIS)

The data collection procedures in the Regional Energy Information System (REIS) are designed to coordinate with those rules and regulations written by the Minnesota Energy Agency which govern electric utility, natural gas utility, and prime petroleum supp...

R. D. Visness N. L. Chervany J. D. Naumann

1975-01-01

26

76 FR 40377 - Agency Information Collection Activities; Proposed Collection; Comment Request; Class II Special...  

Federal Register 2010, 2011, 2012, 2013

...information to establish performance standards to provide such assurance. Condoms without spermicidal lubricant containing nonoxynol-9 are classified in class II. They were originally classified before the enactment of provisions of the Safe...

2011-07-08

27

DOE/SBIR Phase II Final Report: Distributed Relevance Ranking in Heterogeneous Document Collections.  

National Technical Information Service (NTIS)

This report contains the comprehensive summary of the work performed on the SBIR Phase II project (Distributed Relevance Ranking in Heterogeneous Document Collections) at Deep Web Technologies (http://www.deepwebtech.com). We have successfully completed a...

A. Lederman

2006-01-01

28

METEORLOGICAL AND CHEMICAL DATA COLLECTED IN THE UNITED STATES TO INFER DRY DEPOSITION OF TRACE CONTAMINANTS  

EPA Science Inventory

The Atmospheric Turbulence and Diffusion Division is responsible for the operation of a prototype network developed to collect meteorological and surface condition data. The network of meteorological and chemical filterpack monitoring stations has been in operation since the summ...

29

Forensic collection of trace chemicals from diverse surfaces with strippable coatings.  

PubMed

Surface sampling for chemical analysis plays a vital role in environmental monitoring, industrial hygiene, homeland security and forensics. The standard surface sampling tool, a simple cotton gauze pad, is failing to meet the needs of the community as analytical techniques become more sensitive and the variety of analytes increases. In previous work, we demonstrated the efficacy of non-destructive, conformal, spray-on strippable coatings for chemical collection from simple glass surfaces. Here we expand that work by presenting chemical collection at a low spiking level (0.1 g m(-2)) from a diverse array of common surfaces - painted metal, engineering plastics, painted wallboard and concrete - using strippable coatings. The collection efficiency of the strippable coatings is compared to and far exceeds gauze pads. Collection from concrete, a particular challenge for wipes like gauze, averaged 73% over eight chemically diverse compounds for the strippable coatings whereas gauze averaged 10%. PMID:24040648

Jakubowski, Michael J; Beltis, Kevin J; Drennan, Paul M; Pindzola, Bradford A

2013-11-01

30

KIVA-II: A Computer Program for Chemically Reactive Flows with Sprays.  

National Technical Information Service (NTIS)

This report documents the KIVA-II computer program for the numerical calculation of transient, two- and three-dimensional, chemically reactive fluid flows with sprays. KIVA-II extends and enhances the earlier KIVA code, improving its computational accurac...

A. A. Amsden P. J. O'Rourke T. D. Butler

1989-01-01

31

Collection, chemical analysis, and evaluation of coal samples in 1975  

USGS Publications Warehouse

During 1975, the U.S. Geological Survey, in cooperation with other Federal and State agencies, university groups, and private companies, continued its program to augment and refine information on the composition of coal in the United States. This report includes all analytical data on 799 channel samples of coal beds from major operating mines and core holes in 28 States, collected mainly by State Geological Surveys under a cooperative program funded largely by the U.S. Energy Research and Development Administration. For each sample, the U.S. Geological Survey has quantitatively determined the amounts of 24 major, minor, and trace elements (including AI, As, Cd, Cu, F, Hg, Mn, Na, Pb, Se, U, and Zn), and has semiquantitatively determined the concentrations of 15 to 20 additional trace elements (including B, Be, Cr, Ge, Mo, Ni, and V). In addition, the U.S. Bureau of Mines has provided proximate and ultimate analyses, and Btu and forms-of-sulfur determinations on 488 of the samples. Statistical summaries of the data are given for all coal samples in the United States, for coal divided by rank (53 anthracite, 509 bituminous coal, 183 subbituminous coal, and 54 lignite samples), and the arithmetic means, ranges, and geometric means and deviations are given for the coal in each of seven different major coal areas in the United States. For example, the average coal in the United States contains 11.3 percent ash, 10.0 percent moisture, 2.0 percent sulfur, and has 11,180 Btu per pound; of the 10 major oxides determined on the 525?C ash, the average SiO2 content is 38 percent, Al2O3 20 percent, and Na2O 0.67 percent; the average Cd content is 7.3 ppm, Pb 114 ppm, and Zn 151 ppm (range 1 ppm to 6.0 percent). As determined on the raw coal, the average Hg content is 0.18 ppm (range <0.01 to 63.0 ppm), the Se content 4.1 ppm (range <0.1 to 150 ppm), and the U content 1.8 ppm (range <0.2 to 42.9 ppm).

Swanson, Vernon Emanuel; Medlin, J. H.; Hatch, J. R.; Coleman, S. L.; Wood, G. H.. Jr.; Woodruff, S. D.; Hildebrand, R. T.

1976-01-01

32

Characterization of Solid and Liquid GB Samples Collected from M55 Rockets Processed at Anniston Chemical Agent Disposal Facility (ANCDF).  

National Technical Information Service (NTIS)

The Program Manager, Assembled Chemical Weapon Alternatives (PM- ACWA), requested that the U.S. Army Edgewood Chemical Biological Center (ECBC) conduct a fall analytical characterization of a OB sample collected at the Anniston Chemical Agent Disposal Fac...

T. E. Rosso J. J. Loss S. D. Norman P. L. Abercrombie A. B. Butrow

2005-01-01

33

40 CFR Table II-2 to Subpart II - Collection Efficiencies of Anaerobic Processes  

Code of Federal Regulations, 2013 CFR

...Efficiencies of Anaerobic Processes Anaerobic process type Cover type Methane collection efficiency Covered anaerobic lagoon (biogas capture) Bank to bank, impermeable 0.975 Modular, impermeable 0.70 Anaerobic sludge digester; anaerobic...

2013-07-01

34

Tree Resin Composition, Collection Behavior and Selective Filters Shape Chemical Profiles of Tropical Bees (Apidae: Meliponini)  

PubMed Central

The diversity of species is striking, but can be far exceeded by the chemical diversity of compounds collected, produced or used by them. Here, we relate the specificity of plant-consumer interactions to chemical diversity applying a comparative network analysis to both levels. Chemical diversity was explored for interactions between tropical stingless bees and plant resins, which bees collect for nest construction and to deter predators and microbes. Resins also function as an environmental source for terpenes that serve as appeasement allomones and protection against predators when accumulated on the bees' body surfaces. To unravel the origin of the bees' complex chemical profiles, we investigated resin collection and the processing of resin-derived terpenes. We therefore analyzed chemical networks of tree resins, foraging networks of resin collecting bees, and their acquired chemical networks. We revealed that 113 terpenes in nests of six bee species and 83 on their body surfaces comprised a subset of the 1,117 compounds found in resins from seven tree species. Sesquiterpenes were the most variable class of terpenes. Albeit widely present in tree resins, they were only found on the body surface of some species, but entirely lacking in others. Moreover, whereas the nest profile of Tetragonula melanocephala contained sesquiterpenes, its surface profile did not. Stingless bees showed a generalized collecting behavior among resin sources, and only a hitherto undescribed species-specific “filtering” of resin-derived terpenes can explain the variation in chemical profiles of nests and body surfaces from different species. The tight relationship between bees and tree resins of a large variety of species elucidates why the bees' surfaces contain a much higher chemodiversity than other hymenopterans.

Leonhardt, Sara D.; Schmitt, Thomas; Bluthgen, Nico

2011-01-01

35

Chemical composition and functional properties of Ulva lactuca seaweed collected in Tunisia  

Microsoft Academic Search

The chemical composition and some functional properties of the dried “Ulva lactuca” algae, collected from the littoral between the Taboulba and Sayada area, were determined. The dried “U. lactuca” algae were investigated for their soluble, insoluble and total dietary fibre content, mineral amount, amino acid and fatty acid profiles, swelling capacity (SWC), water holding capacity (WHC) and oil holding capacity

Hela Yaich; Haikel Garna; Souhail Besbes; Michel Paquot; Christophe Blecker; Hamadi Attia

2011-01-01

36

Notes on caridean shrimps collected during the Snellius-II expedition. I. Associates of Anthozoa  

NASA Astrophysics Data System (ADS)

During the Snellius-II Expedition to Indonesian waters in 1984, ten species of shrimp were collected associated with Anthozoa (Actiniaria: 6 species; Corallimorpharia: 1 species; Scleractinia: 3 species). These species are: Thor amboinensis (Hippolytidae), Periclimenes brevicarpalis, P. aff. inornatus, P. ornatus, P. holthuisi, P. magnificus, Pliopontonia furtiva, Paratypton siebenrocki, Philarius gerlachei and Jocaste japonica (all Palaemonidae, Pontoniinae). Four new associations and four new records for Indonesian waters were established. Biogeographical aspects, as well as taxonomic problems in some groups are discussed.

Fransen, C. H. J. M.

37

Sampler for collection and analysis of low vapor pressure chemical (LVPC) particulates/aerosols.  

PubMed

Detection of low vapor pressure chemicals (LVPCs) such as pesticides and other toxic/hazardous materials on various environmental surfaces as well as LVPC aerosols is a significant challenge for current vapor phase detectors. We describe a novel sampling device which utilizes stainless steel screens coated with a sticky polydimethylsiloxane coating for collecting LVPCs aerosolized off of a surface. Results are presented for the collection and detection of a pesticide simulant, dimethyl methylphosphonate sorbed onto silica gel (DMMP/SG), using direct analysis in real time-cylindrical ion trap mass spectrometry (DART-CITMS). PMID:24053780

Ewing, K J; Gibson, D; Sanghera, J; Miklos, F

2013-10-15

38

[Chemical and genetic diversity of Ligularia plants collected in the Hengduan Mountains, China].  

PubMed

The Hengduan Mountains area of China is rich in plant resources. The Ligularia species, which belong to Senecioneae and Asteraceae, distributed in this area are highly diversified and contain 6 sections and over 100 species, and are considered to be in on-going evolution and diversification. To understand the inter- and intra-specific diversity of these plants and to elucidate the mechanism of diversification, we analyzed Ligularia plants by chemical, genetic, geographical, ecological, and morphological approaches. We investigated 4 species, and isolated 26 novel compounds. Based on the chemical composition of root extract as well as nucleotide sequence variations in internal transcribed spacers (ITS), we obtained 3 findings. (i) L. virgaurea is classified into two groups, ligularol type and virgaurenone type from the view point of chemical constituents, which are phylogenetically distinguished from each other, (ii) L. subspicata and L. lamarum have an overlapped chemical spectrum, but showed no clear genetic correlation, and (iii) L. cyathiceps showed no significant variations in either chemical constituents or nucleotide sequences. PMID:23208053

Saito, Yoshinori

2012-01-01

39

Sorption and cosorption of lead (II) and methylene blue on chemically modified biomass.  

PubMed

Sorption and cosorption of lead (Pb(II)) and methylene blue (MB) in aqueous solutions on low-cost biosorbents made from chemically modified agricultural by-products was investigated. Modified cotton exhibited the highest adsorption capacity for Pb(II), while modified cotton and peanut hull had higher equilibrium adsorption capacity of MB than the other biosorbents. Different chemical modification methods of hickory resulted in no great variation on the equilibrium adsorption capacity of Pb(II) and MB except for the one treated with alkali. Simultaneous sorption of Pb(II) and MB on the biosorbents showed Pb(II) to be preferentially adsorbed at higher Pb(II)-to-MB molar ratios in solution except for modified peanut hull. The equilibrium Pb adsorption contents decreased with the increasing pre-loading of MB and vice versa, suggesting the competitive rather than synergistic adsorption of the two contaminants on the biosorbents. PMID:24998306

Ding, Zhuhong; Hu, Xin; Zimmerman, Andrew R; Gao, Bin

2014-09-01

40

Chemical composition and radioactivity in hokutolite (plumbian barite) collected at Peito hot spring, Taiwan  

Microsoft Academic Search

Chemical composition and radionuclide concentrations were determined for hokutolite, plumbian barite, collected at Peito hot spring, Taiwan. The hokutolite, precipitated on the surface of the base rock, was scraped into 20 layers from the surface. Barium and Pb were determined by inductively coupled plasma-atomic emission spectroscopy, and 228Ra, 226Ra and 210Pb were determined by ?-ray spectrometry. Comparison of the 228Ra226Ra

Noriyuki Momoshima; Junichi Nita; Yonezo Maeda; Sinji Sugihara; Isamu Shinno; Nobuaki Matsuoka; Chin-Wang Huang

1997-01-01

41

Notes on the KIVA-II software and chemically reactive fluid mechanics.  

National Technical Information Service (NTIS)

This report represents a set of working notes regarding the mechanics of chemically reactive fluids with sprays, and their numerical simulation with the KIVA-II software. KIVA-II is a large FORTRAN program developed at Los Alamos National Laboratory for i...

M. J. Holst

1992-01-01

42

Sustainability Indicators for Chemical Processes : II. Data Needs  

EPA Science Inventory

In order to begin repair of the environmental quality of the planet, there is a need to embrace sustainable development at many levels of the chemical industry and society. One way that the chemical industry is responding to this need is through sustainability evaluations, retrof...

43

Chemical mass balances in metalliferous deposits from the Atlantis II Deep, Red Sea  

Microsoft Academic Search

In order to assess the quantitative distribution of mineral species within the sedimentary series of the Atlantis II Deep, we have examined the chemical composition, mineralogy, and physical properties of 120 sediment samples from two cores that sampled the entire sediment sequences in the West and South-West basins. Biostratigraphic correlations and chemical budget calculations indicate that the nonmetalliferous solid fractions

Pierre Anschutz; Gérard Blanc

1995-01-01

44

An intelligent data collection tool for chemical safety/risk assessment.  

PubMed

REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) is the new European chemical legislation which aims to assess risk or safety of tens of thousands of chemicals to improve the protection of human health and the environment. The chemical safety assessment process is of an iterative nature. First, an initial, worst-case assessment is conducted after which refinements are made until no risk has been estimated or the risk is adequately controlled. Wasting time and resources on additional testing and implementing risk management measures with low effect on risk conclusions should be avoided as much as possible. This paper demonstrates the usefulness of an intelligent data collection strategy based on a sensitivity (and uncertainty) analysis on the risk assessment model EUSES to identify and order the most important "within-EU-TGD-reducible" input parameters influencing the local and regional risk characterisation ratios. The ordering can be adjusted for the costs involved in additional testing (e.g. ecotoxicity, physico-chemical properties, emission estimates, etc.). The risk refinement tool therefore reduces the resources needed to obtain a realistic risk estimate (both less conservative and less uncertain) as efficient as possible. PMID:17959222

Verdonck, Frederik A M; Van Sprang, Patrick A; Vanrolleghem, Peter A

2008-02-01

45

Chemical Composition and Manufacturing Technology of a Collection of Various Types of Islamic Glazes Excavated from Jordan  

Microsoft Academic Search

A collection of Islamic glazed pottery shards that were excavated from the archaeological site of Dohaleh\\/Northern Jordan were chemically analysed. The glazes belong to three different decorative styles. The chemical analysis of the glazes was carried out using energy dispersive x-ray fluorescence. The chemical analysis results enable the classification of the glazes into the three distinct compositional groups with reference

Ziad Al-Saad

2002-01-01

46

Chemical Compaction Aids for Fine-Grained Soils. Volume II.  

National Technical Information Service (NTIS)

The report includes moisture-density-strength screening tests performed on several additional chemicals and an evaluation of the standard AASHTO T-99 moisture-density test results performed on soil specimens prepared under varying conditions of drying, pu...

J. M. Hoover R. L. Handy

1978-01-01

47

Feasibility Study of Chemical Industry in Southwestern Pennsylvania. Phase II.  

National Technical Information Service (NTIS)

An integrated development plan should be prepared for a chemical complex to produce polyvinyl chloride and caustic employing a combination calcium carbide and caustic chlorine facility located at Reesedale, Pennsylvania. An integrated development plan sho...

1964-01-01

48

H II region in NGC 6744: Spectrophotometry and chemical abundances  

SciTech Connect

Spectrophotometry of emission lines in the lambdalambda3700--6800 spectral range is presented for An H II region in an outer arm of NGC6744, a southern hemisphere galaxy of type SAB(r)bc II. The electron temperature, derived from the (O III) lines and assuming N/sub e/ = 100 cm/sup -3/, was found to be 9,630 +- 450 K. Ionic abundances, derived in the usual fashion from the measured line strengths, were corrected to total relative number abundances by application of the standard ionization correction factor (ICF) scheme and by comparison to models. The derived abundances, relative to log Hequivalent12.00, are log He = 10.96 +- 0.06, log N = 7.34 +- 0.26, log O log O = 8.44 +- 0.10, log Ne = 7.80 +- 0.16, and log S = 6.75 +- 0.28. The NGC 6744 H II region abundances, and various ratios, are compared to similar data for H II regions in the SMC, LMC, and the Perseus arm of the Galaxy,. From the comparison it is suggested that the histories of nucleosynthesis in the outer regions of NGC 6744 and the Galaxy could have been quite similar.

Talent, D.L.

1982-01-15

49

Chemical imaging: II. Trends in practical multiparameter sensor systems  

Microsoft Academic Search

In most applications of chemical sensors today the original output of an individual sensor is monitored as one ‘feature’ (such as a certain current at a fixed potential of an electrochemical cell or a resistance of a metal oxide sensor). However, individual sensors and the determination of individual features show limited performance only for most practical applications. Often, arrays of

Udo Weimar; Wolfgang Göpel

1998-01-01

50

A River as a Chemical Reactor. Volume II.  

National Technical Information Service (NTIS)

The report covers four years of research on the control of water quality in a tidal estuary. The contents include: Chemical reactor theory applied to modeling the dynamics of a control system for water quality of a river - feasibility study; Study of a ri...

E. C. Bobalek K. I. Mumme W. W. Turner K. S. Webster L. W. Zabel

1971-01-01

51

Efficiency of Cd(II) removal from aqueous media using chemically modified polystyrene foam  

Microsoft Academic Search

The removal of Cd(II) using polystyrene foam chemically modified with 2,2?-bipyridine has been investigated. The modified polystyrene foam has been characterized by FT-IR spectroscopy, thermogravimetry, elemental analysis and scanning electron microscopy. The solid was employed as a Cd(II) adsorption from aqueous solutions at room temperature. The effects of several variables (pH, shaking speed, agitation time, metal concentration and presence of

Jamil R. Memon; Saima Q. Memon; M. I. Bhanger; M. Y. Khuhawar; Geoffrey C. Allen; G. Zuhra Memon; A. G. Pathan

2008-01-01

52

DOE SBIR Phase II Final Report: Distributed Relevance Ranking in Heterogeneous Document Collections  

SciTech Connect

This report contains the comprehensive summary of the work performed on the SBIR Phase II project (“Distributed Relevance Ranking in Heterogeneous Document Collections”) at Deep Web Technologies (http://www.deepwebtech.com). We have successfully completed all of the tasks defined in our SBIR Proposal work plan (See Table 1 - Phase II Tasks Status). The project was completed on schedule and we have successfully deployed an initial production release of the software architecture at DOE-OSTI for the Science.gov Alliance's search portal (http://www.science.gov). We have implemented a set of grid services that supports the extraction, filtering, aggregation, and presentation of search results from numerous heterogeneous document collections. Illustration 3 depicts the services required to perform QuickRank™ filtering of content as defined in our architecture documentation. Functionality that has been implemented is indicated by the services highlighted in green. We have successfully tested our implementation in a multi-node grid deployment both within the Deep Web Technologies offices, and in a heterogeneous geographically distributed grid environment. We have performed a series of load tests in which we successfully simulated 100 concurrent users submitting search requests to the system. This testing was performed on deployments of one, two, and three node grids with services distributed in a number of different configurations. The preliminary results from these tests indicate that our architecture will scale well across multi-node grid deployments, but more work will be needed, beyond the scope of this project, to perform testing and experimentation to determine scalability and resiliency requirements. We are pleased to report that a production quality version (1.4) of the science.gov Alliance's search portal based on our grid architecture was released in June of 2006. This demonstration portal is currently available at http://science.gov/search30 . The portal allows the user to select from a number of collections grouped by category and enter a query expression (See Illustration 1 - Science.gov 3.0 Search Page). After the user clicks “search” a results page is displayed that provides a list of results from the selected collections ordered by relevance based on the query expression the user provided. Our grid based solution to deep web search and document ranking has already gained attention within DOE, other Government Agencies and a fortune 50 company. We are committed to the continued development of grid based solutions to large scale data access, filtering, and presentation problems within the domain of Information Retrieval and the more general categories of content management, data mining and data analysis.

Abe Lederman

2007-01-08

53

A new sampler for collecting separate dry and wet atmospheric depositions of trace organic chemicals  

NASA Astrophysics Data System (ADS)

Studies conducted in Saskatchewan and elsewhere have demonstrated the atmospheric transport of agricultural pesticides and other organic contaminants and their deposition into aquatic ecosystems. To date these studies have focused on ambient concentrations in the atmosphere and in wet precipitation. To measure the dry deposition of organic chemicals, a new sampler was designed which uses a moving sheet of water to passively trap dry particles and gasses. The moving sheet of water drains into a reservoir and, during recirculation through the sampler, is passed through an XAD-2 resin column which adsorbs the trapped organic contaminants. All surfaces which contact the process water are stainless steel or Teflon. Chemicals collected can be related to airborne materials depositing into aquatic ecosystems. The sampler has received a United States patent (number 5,413,003 - 9 May 1996) with the Canadian patent pending. XAD-2 resin adsorption efficiencies for 10 or 50 ?g fortifications of ten pesticides ranged from 76% for atrazine (2-chloro-4-ethylamino-6-isopropylamino- S-triazine) to 110% for triallate [ S-(2,3,3-trichloro-2-phenyl)bis(1-methylethyl)carbamothioate], dicamba (2-methoxy-3,6-dichlorobenzoic acid) and toxaphene (chlorinated camphene mixture). Field testing using duplicate samplers showed good reproducibility and amounts trapped were consistent with those from high volume and bulk pan samplers located on the same site. Average atmospheric dry deposition rates of three chemicals, collected for 5 weeks in May and June, were: dicamba, 69 ng m -2 da -1; 2,4-D (2,4-dichlorophenoxyacetic acid), 276 ng m -2 da -1: and, ?-HCH ( ?-1, 2, 3, 4, 5, 6-hexachlorocyclohexane), 327 ng m -2 da -1.

Waite, Don T.; Cessna, Allan J.; Gurprasad, Narine P.; Banner, James

54

Chemical management in fungicide sensivity of Mycosphaerella fijiensis collected from banana fields in México.  

PubMed

The chemical management of the black leaf streak disease in banana caused by Mycosphaerella fijiensis (Morelet) requires numerous applications of fungicides per year. However this has led to fungicide resistance in the field. The present study evaluated the activities of six fungicides against the mycelial growth by determination of EC50 values of strains collected from fields with different fungicide management programs: Rustic management (RM) without applications and Intensive management (IM) more than 25 fungicide application/year. Results showed a decreased sensitivity to all fungicides in isolates collected from IM. Means of EC50 values in mg L(-1) for RM and IM were: 13.25 ± 18.24 and 51.58 ± 46.14 for azoxystrobin, 81.40 ± 56.50 and 1.8575 ± 2.11 for carbendazim, 1.225 ± 0.945 and 10.01 ± 8.55 for propiconazole, 220 ± 67.66 vs. 368 ± 62.76 for vinclozolin, 9.862 ± 3.24 and 54.5 ± 21.08 for fludioxonil, 49.2125 ± 34.11 and 112.25 ± 51.20 for mancozeb. A molecular analysis for ?-tubulin revealed a mutation at codon 198 in these strains having an EC50 greater than 10 mg L(-1) for carbendazim. Our data indicate a consistency between fungicide resistance and intensive chemical management in banana fields, however indicative values for resistance were also found in strains collected from rustic fields, suggesting that proximity among fields may be causing a fungus interchange, where rustic fields are breeding grounds for development of resistant strains. Urgent actions are required in order to avoid fungicide resistance in Mexican populations of M. fijiensis due to fungicide management practices. PMID:24948956

Aguilar-Barragan, Alejandra; García-Torres, Ana Elisa; Odriozola-Casas, Olga; Macedo-Raygoza, Gloria; Ogura, Tetsuya; Manzo-Sánchez, Gilberto; James, Andrew C; Islas-Flores, Ignacio; Beltrán-García, Miguel J

2014-01-01

55

Chemical management in fungicide sensivity of Mycosphaerella fijiensis collected from banana fields in M?xico  

PubMed Central

The chemical management of the black leaf streak disease in banana caused by Mycosphaerella fijiensis (Morelet) requires numerous applications of fungicides per year. However this has led to fungicide resistance in the field. The present study evaluated the activities of six fungicides against the mycelial growth by determination of EC50 values of strains collected from fields with different fungicide management programs: Rustic management (RM) without applications and Intensive management (IM) more than 25 fungicide application/year. Results showed a decreased sensitivity to all fungicides in isolates collected from IM. Means of EC50 values in mg L?1 for RM and IM were: 13.25 ± 18.24 and 51.58 ± 46.14 for azoxystrobin, 81.40 ± 56.50 and 1.8575 ± 2.11 for carbendazim, 1.225 ± 0.945 and 10.01 ± 8.55 for propiconazole, 220 ± 67.66 vs. 368 ± 62.76 for vinclozolin, 9.862 ± 3.24 and 54.5 ± 21.08 for fludioxonil, 49.2125 ± 34.11 and 112.25 ± 51.20 for mancozeb. A molecular analysis for ?-tubulin revealed a mutation at codon 198 in these strains having an EC50 greater than 10 mg L?1 for carbendazim. Our data indicate a consistency between fungicide resistance and intensive chemical management in banana fields, however indicative values for resistance were also found in strains collected from rustic fields, suggesting that proximity among fields may be causing a fungus interchange, where rustic fields are breeding grounds for development of resistant strains. Urgent actions are required in order to avoid fungicide resistance in Mexican populations of M. fijiensis due to fungicide management practices.

Aguilar-Barragan, Alejandra; Garcia-Torres, Ana Elisa; Odriozola-Casas, Olga; Macedo-Raygoza, Gloria; Ogura, Tetsuya; Manzo-Sanchez, Gilberto; James, Andrew C.; Islas-Flores, Ignacio; Beltran-Garcia, Miguel J.

2014-01-01

56

Microbiological and chemical analyses of ice collected from a commercial poultry processing establishment.  

PubMed

A study was conducted to evaluate the microbiological and chemical characteristics of ice collected from a commercial poultry further processing facility. During each of 3 visits, the following ice samples were collected: 1) freshly prepared, unused ice; 2) product-contact ice from ice-packed poultry parts; 3) product-contact ice from ice-packed poultry that had been visibly inspected and condemned as not for reuse; and 4) product-contact ice from ice-packed poultry that had passed visible inspection and had been prepared for reuse by washing (rinse with potable water and drain). The overall pattern for lowest to highest numbers of total aerobic microorganisms, coliforms, Escherichia coli, and Enterobacteriaceae was as follows: unused ice < washed ice < product-contact ice < condemned ice. Mean levels of total aerobic microorganisms, coliforms, and Enterobacteriaceae in the unused ice were 0.3, 0.4, and 0.4 log10 cfu/mL, respectively. No E. coli was detected in the unused or washed ice, and levels were 0.5 and 1.5 log10 cfu/mL in the product-contact and condemned ice samples, respectively. Mean levels of bacteria enumerated in condemned ice were 0.8, 1.0, and 0.6 log10 cfu/mL higher than the levels of bacteria found in product-contact ice for coliforms, E. coli, and Enterobacteriaceae, respectively. Washing and draining the product-contact ice decreased counts by 0.9, 0.7, 0.5, and 1.7 log10 cfu/mL for total aerobic microorganisms, coliforms, E. coli, and Enterobacteriaceae, respectively. All of the ice samples had similar pH values (pH 6.1 to 6.4). Unused and washed ice were not significantly different for total solids, total suspended solids, total Kjeldahl nitrogen, and chemical oxygen demand. Condemned ice contained the highest concentration of total solids, total suspended solids, total Kjeldahl nitrogen, and chemical oxygen demand, with levels more than 3 times that found in product contact ice. Data from the present study demonstrate that visible contamination in ice corresponds with increased microbiological and chemical contamination. Product-contact ice may be washed and the washing procedure can reduce the bacterial, solids, nitrogen, and organic loads. PMID:20008812

Northcutt, J K; Smith, D

2010-01-01

57

Chemical composition of rainwater collected at two sampling sites in the city of Rijeka.  

PubMed

This study compares the chemical composition of rainwater samples collected at two sampling sites, the first situated in the Rijeka city centre and the second in a suburban site 120 m above the sea level. The rainwater samples were analysed for precipitation weighted average concentrations of hydrogen, sulphate, nitrate, chloride, ammonium, sodium, potassium, calcium, and magnesium. The results suggest that the local washout of the atmosphere enhanced the rainwater acidity in the city centre which also received significant marine contributions of sulphate, calcium, magnesium, and potassium content. Rainwater in the suburban site was affected by soil dust and/or fertilizers used in the nearby gardens, resulting in partial neutralization with rising of pH value. While the content of S-SO4 was practically equal at both sites, the quantities of N-NO3 and N-NH4 nearly doubled at the suburban site. PMID:10376356

Alebi?-Jureti?, A; Sojat, V

1998-09-01

58

Biosorption of Pb(II) from aqueous solutions using chemically modified Moringa oleifera tree leaves  

Microsoft Academic Search

Moringa oleifera leaves (MOL); an agro-waste material has been used as a precursor to prepare a new biosorbent. The leaves were washed with base and citric acid, and obtained new chemically modified MOL biosorbent (CAMOL) for sequestration of Pb(II) from aqueous solution. The biosorbent was characterized by SEM, FTIR spectral and elemental analyses. The effect of experimental parameters such as

D. Harikishore Kumar Reddy; Y. Harinath; K. Seshaiah; A. V. R. Reddy

2010-01-01

59

Students' Chemical Information Project, October 1967 - September 1968. Final Report: Part II.  

ERIC Educational Resources Information Center

Part II of the Students' Chemical Information Project (SCIP), designed to spread the use of computer-based information services among research scientists and technologists, contains details of the project operations, statistics, results of questionnaires and research reports from liaison scientists (See LI 002 562 for Part I). Chapter I: Operation…

Callaghan, A.; And Others

60

Eliminating error in the chemical abundance scale for extragalactic H II regions  

NASA Astrophysics Data System (ADS)

In an attempt to remove the systematic errors which have plagued the calibration of the H II region abundance sequence, we have theoretically modelled the extragalactic H II region sequence. We then used the theoretical spectra so generated in a double-blind experiment to recover the chemical abundances using both the classical electron temperature + ionization correction factor technique and the technique which depends on the use of strong emission lines (SELs) in the nebular spectrum to estimate the abundance of oxygen. We find a number of systematic trends, and we provide correction formulae which should remove systematic errors in the electron temperature + ionization correction factor technique. We also provide a critical evaluation of the various semi-empirical SEL techniques. Finally, we offer a scheme which should help to eliminate systematic errors in the SEL-derived chemical abundance scale for extragalactic H II regions.

López-Sánchez, Á. R.; Dopita, M. A.; Kewley, L. J.; Zahid, H. J.; Nicholls, D. C.; Scharwächter, J.

2012-11-01

61

Chemical and immunological characterization of lipopolysaccharides from phase I and phase II Coxiella burnetii.  

PubMed Central

Lipopolysaccharides (LPSs) isolated from phase I and phase II Coxiella burnetii (LPS I and LPS II, respectively) were analyzed for chemical compositions, molecular heterogeneity by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and immunological properties. The yields of crude phenol-water extracts from phase I cells were roughly three to six times higher than those from phase II cells. Purification of LPSs by ultracentrifugation gave similar yields for both LPS I and LPS II. Purified LPS I and LPS II contained roughly 0.8 and 0.6% protein, respectively. The fatty acid constituents of the LPSs were different in composition and content, with branched-chain fatty acids representing about 15% of the total. beta-Hydroxymyristic acid was not detected in either LPS I or LPS II. A thiobarbituric acid-periodate-positive compound was evident in the LPSs; however, this component was not identified as 3-deoxy-D-mannooctulosonic acid by gas and paper chromatographies. LPS II contained D-mannose, D-glucose, D-glyceromannoheptose, glucosamine, ethanolamine, 3-deoxy-D-mannooctulosonic acid-like material, phosphate, and fatty acids. LPS I contained the unique disaccharide galactosaminuronyl glucosamine and nine unidentified components in addition to the components of LPS II. The hydrophobic, putative lipid A fraction of LPS I and LPS II contained the above constituents, but the hydrophilic fraction was devoid of ethanolamine. The LPS I disaccharide galactosaminuronyl glucosamine was found in both fractions of the acetic acid hydrolysates. Analysis of LPSs by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by silver staining indicated that LPS II was composed of only one band, whereas LPS I consisted of six or more bands with irregular spacing. Ouchterlony immunodiffusion tests demonstrated that LPS I reacted with phase I but not with phase II whole-cell hyperimmune antibody, and LPS II reacted neither with phase I nor phase II hyperimmune antibody. From these results, it was concluded that the chemical structures of LPSs from C. burnetii were different from those of the LPSs of gram-negative bacteria; however, the LPS structural variation in C. burnetii may be similar to the smooth-to-rough mutational variation of saccharide chain length in gram-negative bacteria. Images

Amano, K; Williams, J C

1984-01-01

62

Chemical Analysis of Fractionated Halogens in Atmospheric Aerosols Collected in Okinawa, Japan  

NASA Astrophysics Data System (ADS)

Halogens (Cl, Br and I) play important roles in the atmosphere, e.g. ozone depletion by Br during spring in Polar Regions. Sources of halogens in atmospheric aerosols are mainly from ocean. But, for example, when we analyzed Br- with ion chromatography, its concentrations were almost always below the detection limit, which is also much lower than the estimated concentrations from sodium ion concentrations. We hypothesized that portions of halogens are escaped to the atmosphere, similar to chlorine loss, changed their chemical forms to such as BrO3- and IO3-, and/or even formed precipitates. There was few reported data so far about fractionated halogen concentrations in atmospheric aerosols. Thus, purpose of this study was to determine halogen concentrations in different fractions; free ion, water-soluble chemically transformed ions and precipitates using the authentic aerosols. Moreover, we analyzed seasonal variation for each fraction. Atmospheric aerosol samples were collected at Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS) of Okinawa, Japan during January 2010 and August 2013. A high volume air sampler was used for collecting total particulate matters on quartz filters on a weekly basis. Ultrapure water was used to extract water-soluble factions of halogens. The extracted solutions were filtered with the membrane filter and used for chemical analysis with ion chromatography and ICP-MS. Moreover, the total halogens in aerosols were obtained after digesting aerosols with tetramethylammonium hydroxide (TMAH) using the microwave and analysis with ICP-MS. For Cl, water-soluble Cl- accounted for about 70% of the estimates with Na content. No other forms of water-soluble Cl were found. About 30% of Cl was assumed volatilized to the gas-phase. For Br, water-soluble Br accounted for about 43% of the estimates with Na content, and within the 43%, about 10% of Br was not in the form of Br-. About 46% of Br was assumed volatilized to the gas-phase. For I, fractioned concentrations are still under investigation, and will be reported and discussed during the meeting. For seasonal variation, in general, concentrations of halogens were the lowest in summer and higher in fall and winter, reflecting air mass movement and wind speed around Okinawa, Japan.

Tsuhako, A.; Miyagi, Y.; Somada, Y.; Azechi, S.; Handa, D.; Oshiro, Y.; Murayama, H.; Arakaki, T.

2013-12-01

63

Chemical investigations of Atlantis II and discovery brines in the Red Sea  

Microsoft Academic Search

Analytical data for the Atlantis II and Discovery deeps in the Red Sea are given. The data were collected in March and June 1976 during the 22nd cruise of R\\/V Akademik Kurchatov in the Indian Ocean. On board analyses were performed of density, chlorinity, Mg, Ca, Sr and trace elements. The salinity, calculated from the density, is related to the

Lars-Göran Danielsson; David Dyrssen; Anders Granéli

1980-01-01

64

Sensors, Volume 3, Part II, Chemical and Biochemical Sensors Part II  

Microsoft Academic Search

'Sensors' is the first self-contained series to deal with the whole area of sensors. It describes general aspects, technical and physical fundamentals, construction, function, applications and developments of the various types of sensors. This is the second of two volumes focusing on chemical and biochemical sensors. It includes a detailed description of biosensors which often make use of transducer properties

Wolfgang Göpel; T. A. Jones; Michel Kleitz; Ingemar Lundström; Tetsuro Seiyama

1997-01-01

65

Biotechnology for producing fuels and chemicals from biomass. Volume II. Fermentation chemicals from biomass  

SciTech Connect

The technological and economic feasibility of producing some selected chemicals by fermentation is discussed: acetone, butanol, acetic acid, citric acid, 2,3-butanediol, and propionic acid. The demand for acetone and butanol has grown considerably. They have not been produced fermentatively for three decades, but instead by the oxo and aldol processes. Improved cost of fermentative production will hinge on improving yields and using cellulosic feedstocks. The market for acetic acid is likely to grow 5% to 7%/yr. A potential process for production is the fermentation of hydrolyzed cellulosic material to ethanol followed by chemical conversion to acetic acid. For about 50 years fermentation has been the chief process for citric acid production. The feedstock cost is 15% to 20% of the overall cost of production. The anticipated 5%/yr growth in demand for citric acid could be enhanced by using it to displace phosphates in detergent manufacture. A number of useful chemicals can be derived from 2,3-butanediol, which has not been produced commercially on a large scale. R and D are needed to establish a viable commercial process. The commercial fermentative production of propionic acid has not yet been developed. Recovery and purification of the product require considerable improvement. Other chemicals such as lactic acid, isopropanol, maleic anhydride, fumarate, and glycerol merit evaluation for commercial fermentative production in the near future.

Villet, R. (ed.)

1981-02-01

66

Contributions of type II and Ib/c supernovae to Galactic chemical evolution  

NASA Astrophysics Data System (ADS)

Type II and Ib/c supernovae (SNe II and Ib/c) have made major stellar nucleosynthetic contributions to the inventories of stable nuclides during chemical evolution of the Galaxy. A case study is performed here with the help of recently developed numerical simulations of Galactic chemical evolution in the solar neighborhood to understand the contributions of SNe II and Ib/c by comparing the stellar nucleosynthetic yields obtained by two leading groups in this field. These stellar nucleosynthetic yields differ in terms of their treatment of stellar evolution and nucleosynthesis. The formulation describing Galactic chemical evolution is developed with the recently revised solar metallicity of ~0.014. Furthermore, the recent nucleosynthetic yields of stellar models based on the revised solar metallicity are also used. The analysis suggests that it could be difficult to explain, in a self-consistent manner, the various features associated with the elemental evolutionary trends over Galactic timescales by any single adopted stellar nucleosynthetic model that incorporates SNe II and Ib/c.

Sahijpal, Sandeep

2014-06-01

67

Evaluation of the ESP Culture System II for recovery of mycobacteria from blood specimens collected in isolator tubes.  

PubMed Central

The reliability of the ESP Culture System II (ESP II; AccuMed International, Westlake, Ohio), a continuously monitoring, nonradiometric mycobacterial culture system, for recovery of mycobacteria from sediments of blood collected in an Isolator tube was evaluated by comparing its performance to inoculation of the sediment onto Middlebrook 7H11/7H11 selective biplates. Of 1,704 blood specimens, 73 (4.3%) were positive for mycobacteria (68 Mycobacterium avium complex and 5 M. tuberculosis). Fifty-three specimens were positive by both methods; 13 were positive by ESP II only, and 7 were positive by Middlebrook agar only (chi square = 1.8; P > 0.05). The mean times to positivity were 15.6 days for ESP II and 19.0 days for Middlebrook agar (P < 0.01). The time to detection was the same for 13 specimens; ESP II was positive first for 33, and agar plates were positive first for 7. ESP II allowed recovery of more mycobacteria (90.4% of all isolates versus 82.2% for Middlebrook agar) from sediments of blood specimens collected in Isolator tubes, and it provided significantly faster detection than did Middlebrook plates.

Tholcken, C A; Huang, S; Woods, G L

1997-01-01

68

Evaluation of the ESP Culture System II for recovery of mycobacteria from blood specimens collected in isolator tubes.  

PubMed

The reliability of the ESP Culture System II (ESP II; AccuMed International, Westlake, Ohio), a continuously monitoring, nonradiometric mycobacterial culture system, for recovery of mycobacteria from sediments of blood collected in an Isolator tube was evaluated by comparing its performance to inoculation of the sediment onto Middlebrook 7H11/7H11 selective biplates. Of 1,704 blood specimens, 73 (4.3%) were positive for mycobacteria (68 Mycobacterium avium complex and 5 M. tuberculosis). Fifty-three specimens were positive by both methods; 13 were positive by ESP II only, and 7 were positive by Middlebrook agar only (chi square = 1.8; P > 0.05). The mean times to positivity were 15.6 days for ESP II and 19.0 days for Middlebrook agar (P < 0.01). The time to detection was the same for 13 specimens; ESP II was positive first for 33, and agar plates were positive first for 7. ESP II allowed recovery of more mycobacteria (90.4% of all isolates versus 82.2% for Middlebrook agar) from sediments of blood specimens collected in Isolator tubes, and it provided significantly faster detection than did Middlebrook plates. PMID:9316935

Tholcken, C A; Huang, S; Woods, G L

1997-10-01

69

EXPERIMENTAL EVALUATION OF CHEMICAL SEQUESTRATION OF CARBON DIOXIDE IN DEEP AQUIFER MEDIA - PHASE II  

SciTech Connect

In 1998 Battelle was selected by the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL) under a Novel Concepts project grant to continue Phase II research on the feasibility of carbon dioxide (CO{sub 2}) sequestration in deep saline formations. The focus of this investigation is to conduct detailed laboratory experiments to examine factors that may affect chemical sequestration of CO{sub 2} in deep saline formations. Reactions between sandstone and other geologic media from potential host reservoirs, brine solutions, and CO{sub 2} are being investigated under high-pressure conditions. Some experiments also include sulfur dioxide (SO{sub 2}) gases to evaluate the potential for co-injection of CO{sub 2} and SO{sub 2} related gases in the deep formations. In addition, an assessment of engineering and economic aspects is being conducted. This current Technical Progress Report describes the status of the project as of September 2000. The major activities undertaken during the quarter included several experiments conducted to investigate the effects of pressure, temperature, time, and brine composition on rock samples from potential host reservoirs. Samples (both powder and slab) were taken from the Mt. Simon Sandstone, a potential CO{sub 2} host formation in the Ohio, the Eau Claire Shale, and Rome Dolomite samples that form the caprock for Mt. Simon Sandstone. Also, a sample with high calcium plagioclase content from Frio Formation in Texas was used. In addition, mineral samples for relatively pure Anorthite and glauconite were experimented on with and without the presence of additional clay minerals such as kaolinite and montmorillonite. The experiments were run for one to two months at pressures similar to deep reservoirs and temperatures set at 50 C or 150 C. Several enhancements were made to the experimental equipment to allow for mixing of reactants and to improve sample collection methods. The resulting fluids (gases and liquids) as well as the rock samples were characterized to evaluate the geochemical changes over the experimental period. Preliminary results from the analysis are presented in the report. More detailed interpretation of the results will be presented in the technical report at the end of Phase II.

Neeraj Gupta; Bruce Sass; Jennifer Ickes

2000-11-28

70

Collection and Chemical Composition of Phloem Sap from Citrus sinensis L. Osbeck (Sweet Orange).  

PubMed

Through utilizing the nutrient-rich phloem sap, sap feeding insects such as psyllids, leafhoppers, and aphids can transmit many phloem-restricted pathogens. On the other hand, multiplication of phloem-limited, uncultivated bacteria such as Candidatus Liberibacter asiaticus (CLas) inside the phloem of citrus indicates that the sap contains all the essential nutrients needed for the pathogen growth. The phloem sap composition of many plants has been studied; however, to our knowledge, there is no available data about citrus phloem sap. In this study, we identified and quantified the chemical components of phloem sap from pineapple sweet orange. Two approaches (EDTA enhanced exudation and centrifugation) were used to collect phloem sap. The collected sap was derivatized with methyl chloroformate (MCF), N-methyl-N- [tert-butyl dimethylsilyl]-trifluroacetamide (MTBSTFA), or trimethylsilyl (TMS) and analyzed with GC-MS revealing 20 amino acids and 8 sugars. Proline, the most abundant amino acid, composed more than 60% of the total amino acids. Tryptophan, tyrosine, leucine, isoleucine, and valine, which are considered essential for phloem sap-sucking insects, were also detected. Sucrose, glucose, fructose, and inositol were the most predominant sugars. In addition, seven organic acids including succinic, fumaric, malic, maleic, threonic, citric, and quinic were detected. All compounds detected in the EDTA-enhanced exudate were also detected in the pure phloem sap using centrifugation. The centrifugation technique allowed estimating the concentration of metabolites. This information expands our knowledge about the nutrition requirement for citrus phloem-limited bacterial pathogen and their vectors, and can help define suitable artificial media to culture them. PMID:25014027

Hijaz, Faraj; Killiny, Nabil

2014-01-01

71

Collection and Chemical Composition of Phloem Sap from Citrus sinensis L. Osbeck (Sweet Orange)  

PubMed Central

Through utilizing the nutrient-rich phloem sap, sap feeding insects such as psyllids, leafhoppers, and aphids can transmit many phloem-restricted pathogens. On the other hand, multiplication of phloem-limited, uncultivated bacteria such as Candidatus Liberibacter asiaticus (CLas) inside the phloem of citrus indicates that the sap contains all the essential nutrients needed for the pathogen growth. The phloem sap composition of many plants has been studied; however, to our knowledge, there is no available data about citrus phloem sap. In this study, we identified and quantified the chemical components of phloem sap from pineapple sweet orange. Two approaches (EDTA enhanced exudation and centrifugation) were used to collect phloem sap. The collected sap was derivatized with methyl chloroformate (MCF), N-methyl-N- [tert-butyl dimethylsilyl]-trifluroacetamide (MTBSTFA), or trimethylsilyl (TMS) and analyzed with GC-MS revealing 20 amino acids and 8 sugars. Proline, the most abundant amino acid, composed more than 60% of the total amino acids. Tryptophan, tyrosine, leucine, isoleucine, and valine, which are considered essential for phloem sap-sucking insects, were also detected. Sucrose, glucose, fructose, and inositol were the most predominant sugars. In addition, seven organic acids including succinic, fumaric, malic, maleic, threonic, citric, and quinic were detected. All compounds detected in the EDTA-enhanced exudate were also detected in the pure phloem sap using centrifugation. The centrifugation technique allowed estimating the concentration of metabolites. This information expands our knowledge about the nutrition requirement for citrus phloem-limited bacterial pathogen and their vectors, and can help define suitable artificial media to culture them.

Hijaz, Faraj; Killiny, Nabil

2014-01-01

72

13C chemical shifts of propane molecules encaged in structure II clathrate hydrate.  

PubMed

Experimental NMR measurements for (13)C chemical shifts of propane molecules encaged in 16-hedral cages of structure II clathrate hydrate were conducted to investigate the effects of guest-host interaction of pure propane clathrate on the (13)C chemical shifts of propane guests. Experimental (13)C NMR measurements revealed that the clathrate hydration of propane reverses the (13)C chemical shifts of methyl and methylene carbons in propane guests to gaseous propane at room temperature and atmospheric pressure or isolated propane, suggesting a change in magnetic environment around the propane guest by the clathrate hydration. Inversion of the (13)C chemical shifts of propane clathrate suggests that the deshielding effect of the water cage on the methyl carbons of the propane molecule encaged in the 16-hedral cage is greater than that on its methylene carbon. PMID:21229965

Kida, Masato; Hori, Akira; Sakagami, Hirotoshi; Takeya, Satoshi; Kamata, Yasushi; Takahashi, Nobuo; Ebinuma, Takao; Narita, Hideo

2011-02-10

73

An RNA conformational change between the two chemical steps of group II self-splicing.  

PubMed Central

As for nuclear pre-mRNA introns, the splicing pathway of group II self-splicing introns proceeds by two successive transesterifications involving substrates with different chemical configurations. These two reactions have been proposed to be catalysed by two active sites, or alternatively by a single active site rearranging its components to accommodate the successive substrates. Here we show that the structural elements specific for the second splicing step are clustered in peripheral structures of domains II and VI. We show that these structures are not required for catalysis of the second chemical step but, instead, take part in a conformational change that occurs between the two catalytic steps. This rearrangement involves the formation of a tertiary contact between part of domain II and a GNRA tetraloop at the tip of domain VI. The fact that domain VI, which carries the branched structure, is involved in this structural rearrangement and the fact that modifications affecting the structures involved have almost no effect when splicing proceeds without branch formation, suggest that the conformational change results in the displacement of the first-step product out of the active site. These observations give further support to the existence of a single active site in group II introns. Images

Chanfreau, G; Jacquier, A

1996-01-01

74

A pipeline of programs for collecting and analyzing group II intron retroelement sequences from GenBank  

PubMed Central

Background Accurate and complete identification of mobile elements is a challenging task in the current era of sequencing, given their large numbers and frequent truncations. Group II intron retroelements, which consist of a ribozyme and an intron-encoded protein (IEP), are usually identified in bacterial genomes through their IEP; however, the RNA component that defines the intron boundaries is often difficult to identify because of a lack of strong sequence conservation corresponding to the RNA structure. Compounding the problem of boundary definition is the fact that a majority of group II intron copies in bacteria are truncated. Results Here we present a pipeline of 11 programs that collect and analyze group II intron sequences from GenBank. The pipeline begins with a BLAST search of GenBank using a set of representative group II IEPs as queries. Subsequent steps download the corresponding genomic sequences and flanks, filter out non-group II introns, assign introns to phylogenetic subclasses, filter out incomplete and/or non-functional introns, and assign IEP sequences and RNA boundaries to the full-length introns. In the final step, the redundancy in the data set is reduced by grouping introns into sets of ?95% identity, with one example sequence chosen to be the representative. Conclusions These programs should be useful for comprehensive identification of group II introns in sequence databases as data continue to rapidly accumulate.

2013-01-01

75

Chemical composition and antibacterial activity of propolis collected by three different races of honeybees in the same region  

Microsoft Academic Search

The chemical analysis and antibacterial activity of three types of propolis collected three different races of Apis mellifera bee in the same apiary were investigated. Propolis samples were investigated by GC\\/MS, 48 compounds were identified 32 being new for propolis. The compounds identified indicated that the main plant sources of propolis were Populus alba, Populus tremuloides and Salix alba. The

Sibel Silici; Semiramis Kutluca

2005-01-01

76

Chemical compositions and XANES speciations of Fe, Mn and Zn from aerosols collected in China and Japan during dust events  

Microsoft Academic Search

Variations of the chemical composition and elemental speciation of aeolian dust transported from China to Japan were investigated in this study. During 6-12 April 2002, a large-scale dust event was observed in China, Korea, and Japan. Aerosol samples collected in Beijing, Fukuoka, Nagoya, and Tsukuba at that time were used for this study. Variations of most elemental concentrations against the

ATSUYUKI OHTA; HIROSHI TSUNO; HIROYUKI KAGI; YUTAKA KANAI; MASAHARU NOMURA; RENJIAN ZHANG; SHIGERU TERASHIMA; NOBORU IMAI

2006-01-01

77

COMPARISON OF MICROBIAL TRANSFORMATION RATE COEFFICIENTS OF XENOBIOTIC CHEMICALS BETWEEN FIELD-COLLECTED AND LABORATORY MICROCOSM MICROBIOTA  

EPA Science Inventory

Two second-order transformation rate coefficients--kb, based on total plate counts, and kA, based on periphyton-colonized surface areas--were used to compare xenobiotic chemical transformation by laboratory-developed (microcosm) and by field-collected microbiota. Similarity of tr...

78

Program for monitoring the chemical quality of ground water in Utah - Summary of data collected through 1984  

Microsoft Academic Search

The US Geological Survey formally started a program for monitoring groundwater quality in Utah during 1957 in cooperation with the Utah Geological Survey. The monitoring program was initiated to detect any changes in chemical quality that might be associated with the withdrawal of water from wells. Dissolved-solids concentrations in water samples collected from the observation wells through 1984 ranged from

D. Price; T. Arnow

1986-01-01

79

BIOLOGICAL ASSESSMENT OF TOXICITY CAUSED BY CHEMICAL CONSTITUENTS ELUTED FROM SITE SOILS COLLECTED AT THE DRAKE CHEMICAL SUPERFUND SITE  

EPA Science Inventory

The site was used to manufactured specialty intermediate chemicals for the producers of dyes, pharmaceuticals, cosmetics, herbicides, and pesticides. he herbicide Fenac (2,3,6-trichlorophenylacetic acid) is a major on- and off-site contaminant. ne hundred twenty -eight soils were...

80

Fe(II)-induced decomposition of epidioxides. A chemical model for prostaglandin E, prostacyclin and thromboxane biosynthesis  

Microsoft Academic Search

Summary A chemical model for biosynthesis of PGE, PGX and the thromboxanes from the prostaglandin endoperoxides is presented which is based on known reactions of other endoperoxides with the Fe(II)?Fe(III) redox system in vitro.

J. A. Turner; W. Herz

1977-01-01

81

Vesicle-based method for collecting, manipulating, and chemically processing trace macromolecular species  

DOEpatents

Disclosed is an apparatus and method for inserting one or several chemical or biological species into phospholipid containers that are controlled within a microfluidic network, wherein individual containers are tracked and manipulated by electric fields and wherein the contained species may be chemically processed.

Davalos, Rafael V. (Oakland, CA) [Oakland, CA; Ellis, Christopher R. B. (Oakland, CA) [Oakland, CA

2010-08-17

82

Vesicle-based method and apparatus for collecting, manipulating, and chemically processing trace macromolecular species  

DOEpatents

Disclosed is an apparatus and method for inserting one or several chemical or biological species into phospholipid containers that are controlled within a microfluidic network, wherein individual containers are tracked and manipulated by electric fields and wherein the contained species may be chemically processed.

Davalos, Rafael V. (Oakland, CA); Ellis, Christopher R. B. (Oakland, CA)

2008-03-04

83

The KIVA-II computer program for transient multidimensional chemically reactive flows with sprays  

SciTech Connect

Since its public release in 1985, the KIVA computer program has been utilized for the time dependent analysis of chemically reacting flows with sprays in two and three space dimensions. This paper describes some of the improvements to the original version that have been made since that time. The new code called KIVA-II is planned for public release in early 1988. KIVA-II improves the earlier version in the accuracy and efficiency of the computational procedure, the accuracy of the physics submodels, and in versatility and ease of use. Numerical improvements include the use of the ICE solution procedure in place of the acoustic subcycling method and the implementation of a quasi-second-order-accurate convection scheme. Major extensions to the physical submodels include the inclusion of an optional k-epsilon turbulence model, and several additions to the spray model. We illustrate some of the new capabilities by means of example solutions. 25 refs., 7 figs.

Amsden, A.A.; Butler, T.D.; O'Rourke, P.J.

1987-01-01

84

Comparison of different methods for collection of volatile chemical markers from fungi  

Microsoft Academic Search

Volatile metabolites from Penicillium vulpinum, cultured on Czapek yeast autolysate agar and broth, were collected by three different methods: (1) diffusive sampling from headspace, (2) purging and trapping of headspace gases, and (3) steam distillation extraction (SDE) of biomass and liquid medium. The qualitative nature and semiquantitative amounts of mainly unsaturated compounds like mono- and sesquiterpenes collected by diffusive sampling

Thomas Ostenfeld Larsen; Jens Christian Frisvad

1995-01-01

85

Chemical modification of equinatoxin II, a lethal and cytolytic toxin from the sea anemone Actinia equina L  

Microsoft Academic Search

T.TURK, P.MALEx and F.GuBEN~EK .Chemical modification of equinatoxin II,a lethaland cytolytictoxin from the sea anemone ActiniaequinaL .Toxicon 27,37384, 1989 .-The role of arginineand tyrosinein cytolyticpropertiesof equinatoxin II,isolatedfrom the sea anemone ActiniaequinaL.,was studied by means of chemical modifications.The toxin was modified with 2,3 butane- dione and tetranitromethane, respectively. The extent of modification and physico-chemical propertiesof the modified proteinswere checked with amino

TOM TURK; P MACEK; F GUBENSEK

1989-01-01

86

Chemical variability of the essential oils from Rosa canina L. and Rosa sempervirens L. flowers collected at Tunisia  

Microsoft Academic Search

The chemical variability of the essential oils of Rosa canina L. and R. sempervirens L. flowers collected at seven localities from northern Tunisia was investigated by gas chromatography (GC) and GC–mass spectrometry (GC–MS). The essential oils yields ranged between 0.7% and 1.4% (v\\/f.w.) for R. canina and R. sempervirens, respectively. Forty-one components were identified in R. canina and twenty-six in

H. Ghazghazi; M. G. Miguel; M. Weslati; B. Hasnaoui; H. Sebei; J. G. Barroso; L. G. Pedro; A. C. Figueiredo

2012-01-01

87

Low Budget Biology II: A Collection of Low Cost Labs and Activities.  

ERIC Educational Resources Information Center

This document contains 13 low budget labs, demonstrations, and activities to be used in the biology classroom. Each activity has a teacher preparation section which states the purpose of each lab, some basic information, a list of materials and what they do, and how to prep the different solutions and chemicals. All labs are designed for a…

Wartski, Bert; Wartski, Lynn Marie

88

Microscopic analysis of nuclear collective motions in terms of the boson expansion theory (II). Numerical calculations  

NASA Astrophysics Data System (ADS)

Anharmonicities in nuclear quadrupole collective motions are studied by applying the self-consistent effective interactions derived in our previous work. Numerical calculations are made in terms of the boson expansion technique of Kishimoto-Tamura with several new refinements developed in the first paper of this series. It is shown that the three-body interaction is necessary to maintain the integrity of the collective modes in the presence of coupling with quasi-particle modes. General agreements with experimental data on nuclei in various mass region have confirmed that our theory is capable of describing various types of anharmonicities characteristic to the nuclei in question.

Sakamoto, Hideo; Kishimoto, Teruo

1991-06-01

89

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

PubMed Central

The trigger loop (TL) of RNA polymerase II (Pol II) is a conserved structural motif that is crucial for Pol II catalytic activity and transcriptional fidelity. The TL remains in an inactive open conformation when the mismatched substrate is bound. In contrast, TL switches from an inactive open state to a closed active state to facilitate nucleotide addition upon the binding of the cognate substrate to the Pol II active site. However, a comprehensive understanding of the specific chemical interactions and substrate structural signatures that are essential to this TL conformational change remains elusive. Here we employed synthetic nucleotide analogues as ‘chemical mutation’ tools coupling with ?-amanitin transcription inhibition assay to systematically dissect the key chemical interactions and structural signatures governing the substrate-coupled TL closure in Saccharomyces cerevisiae Pol II. This study reveals novel insights into understanding the molecular basis of TL conformational transition upon substrate binding during Pol II transcription. This synthetic chemical biology approach may be extended to understand the mechanisms of other RNA polymerases as well as other nucleic acid enzymes in future studies.

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

2014-01-01

90

Long-term observation of water-soluble chemical components in the bulk atmospheric aerosols collected at Okinawa, Japan  

NASA Astrophysics Data System (ADS)

The economic development and population growth in recent Asia spread air pollution. Emission rate of air pollutants from Asia, in particular oxides of nitrogen, surpassed those from North America and Europe and should continue to exceed them for decades. The study of the long-range transported air pollution from Asian continent has gained a special attention in Japan because of increase in photochemical oxidants in relatively remote islands. Okinawa Island is situated approximately 1500 km south of Tokyo, Japan, 2000 km southeast of Beijing, China, and 1000 km south of South Korea. Its location in Asia is well suited for studying long-range transport of air pollutants in East Asia because maritime air mass prevails during summer, while continental air mass dominates during fall, winter, and spring. The maritime air mass data can be seen as background and can be compared with continental air masses which have been affected by anthropogenic activities. Bulk aerosol samples were collected on quartz filters by using a high volume air sampler. Sampling duration was one week for each sample. We determined the concentrations of water-soluble anions, cations and dissolved organic carbon (DOC) in the bulk aerosols collected at the Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS) using ion chromatography, atomic absorption spectrometry, and total organic carbon analyzer, respectively. We will report water-soluble chemical components data of anions, cations and DOC in bulk atmospheric aerosols collected at CHAAMS during August, 2005 to April, 2010. Seasonal variation of water-soluble chemical components showed that the concentrations were relatively low in summer, higher in fall and winter, and the highest in spring. When air mass came from Asian Continent, the concentrations of water-soluble chemical components were much higher compared to the other directions. In addition, we calculated background concentration of water-soluble chemical components at Okinawa, Japan.

Handa, Daishi; Somada, Yuka; Ijyu, Moriaki; Azechi, Sotaro; Nakaema, Fumiya; Arakaki, Takemitsu; Tanahara, Akira

2010-05-01

91

Liquid chromatography electrospray tandem mass spectrometric and desorption electrospray ionization tandem mass spectrometric analysis of chemical warfare agents in office media typically collected during a forensic investigation  

Microsoft Academic Search

Most prior analytical studies have dealt with the determination of chemical warfare agents in environmental or biological matrices that would typically be collected following battlefield use or in support of the Chemical Weapons Convention. These methods may be useful for some investigations, but may not be practical for indoor forensic investigations where chemical warfare agent use is suspected. There is

P. A. D’Agostino; J. R. Hancock; C. L. Chenier; C. R. Jackson Lepage

2006-01-01

92

User Centered System Design. Part II: Collected Papers from the UCSD HMI Project.  

ERIC Educational Resources Information Center

This report is a collection of 11 recent papers by the Human-Machine Interaction Group at the University of California, San Diego. The following papers are included: (1) "Stages and Levels in Human-Machine Interaction," Donald A. Norman; (2) "The Nature of Expertise in UNIX," Stephen W. Draper; (3) "Users in the Real World," David Owen; (4)…

California Univ., San Diego, La Jolla. Inst. for Cognitive Science.

93

Technology Development, Implementation and Evaluation for Collection and Analysis of Explosives Trace Chemical Evidence.  

National Technical Information Service (NTIS)

A method has been developed for sampling surfaces and analyzing for the presence of trace amounts of organic explosives. The method entails the use of a TeflonTM dry surface-wiping material for sample collection, and a common laboratory instrument (a gas ...

2001-01-01

94

Spatial distribution and temporal variation of chemical species in the bulk atmospheric aerosols collected at the Okinawa archipelago, Japan  

NASA Astrophysics Data System (ADS)

The economic development and population growth in recent Asia have been increasing air pollution. A computer simulation study showed that air pollutants emitted from Asian continent could spread quickly within northern hemisphere. We initiated a study to elucidate the special distribution and chemical characterization of atmospheric aerosols around Okinawa archipelago, Japan. Okinawa Island is situated approximately 1500 km south of Tokyo, Japan, 2000 km southeast of Beijing, China, and 1000 km south of South Korea. Its location in Asia is well suited for studying long-range transport of air pollutants in East Asia because maritime air mass prevails during summer, while continental air mass dominates during fall, winter, and spring. The maritime air mass data can be seen as background and can be compared with continental air masses which have been affected by anthropogenic activities. We simultaneously collected bulk aerosol samples by using the same types of high volume air samplers at Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS, Okinawa Island), Kume Island (ca. 160 km south-west of CHAAMS) and Minami-daitou Island (ca. 320 km south-east of CHAAMS). We determined the concentrations of water-soluble anions, cations and dissolved organic carbon (DOC) using ion chromatography, atomic absorption spectrometry, and total organic carbon analyzer, respectively. We report and discuss spatial distribution and temporal variation of chemical species concentrations in bulk atmospheric aerosols collected during July, 2008 to July, 2009. We determine “background” concentration of chemical components in Okinawa archipelago. We then compare each chemical component among CHAAMS, Kume Island and Minami-daito Island to elucidate the influence of the long-range transport of chemical species from Asian continent.

Handa, D.; Somada, Y.; Ijyu, M.; Azechi, S.; Nakaema, F.; Arakaki, T.; Tanahara, A.

2009-12-01

95

Higgs mechanism with type-II Nambu-Goldstone bosons at finite chemical potential  

SciTech Connect

When the spontaneous symmetry breaking occurs for systems without Lorentz covariance, there arises possible mismatch, N{sub NG}II NG bosons emerge. We study how the gauge bosons acquire masses through the Higgs mechanism under this mismatch by employing gauge theories with complex scalar field at finite chemical potential and by enforcing ''charge'' neutrality. To separate the physical spectra from unphysical ones, the R{sub {xi}} gauge is adopted. Not only massless NG bosons but also massive scalar bosons generated by the chemical potential are absorbed into spatial components of the gauge bosons. Although the chemical potential induces a nontrivial mixings among the scalar bosons and temporal components of the gauge bosons, it does not affect the structure of the physical spectra, so that the total number of physical modes is not modified even for N{sub NG}

Hama, Yusuke [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Hatsuda, Tetsuo [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); IPMU, University of Tokyo, Kashiwa 277-8568 (Japan); Theoretical Research Division, Nishina Center, RIKEN, Wako 351-0198 (Japan); Uchino, Shun [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

2011-06-15

96

Collective gyromagnetic ratio from density dependent hartree-fock calculations (II). Odd nuclei  

Microsoft Academic Search

The collective gyromagnetic ratio and moment of inertia of deformed odd-proton and oddneutron axially symmetric nuclei have been calculated in the cranking approximation using wave functions obtained with the Skyrme force SIII. Good agreement with experiment is found for gR. Our parameter-free cranking results are better than those of Prior, Boehm and Nilsson where effective charges were used. The cranking

D. W. L. Sprung; S. G. Lie; M. Valliéres

1981-01-01

97

The Chemical and Biological Profile of a Red Clover (Trifolium pratense) Phase II Clinical Extract  

PubMed Central

Objectives To document the chemical and biological profile of a clinical phase II red clover (Trifolium pratense L.) extract by identifying and measuring the major and minor components visible in the high performance liquid chromatography-ultraviolet (HPLC-UV) chromatogram and evaluating each compound for estrogenic and antioxidant activity. Design Individual compounds in the pre-formulated (i.e., no excipients present) extract were identified by either chemical isolation followed by structure elucidation or by matching to retention time and molecular mass of chemical standards via liquid chromatography-mass spectrometry (LC-MS) analysis. Quantitation of the amounts of compounds found in the pre-formulated extract was done using HPLC-UV or LC-MS. Isolated compounds or standards were evaluated for their ability to 1) induce alkaline phosphatase (AP) in an endometrial carcinoma cell line, 2) competitively bind to recombinant human estrogen receptors (ERs) alpha (?) and beta (?), and 3) act as antioxidants by scavenging 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) free radicals. Results The pre-formulated red clover extract had an EC50 of 2.0–2.2 ?g/mL in the AP estrogenicity assay, and IC50s of 18.4–32.6 ?g/mL and 1.9–3.4 ?g/mL in the ER? and ER? binding assays, respectively. The pre-formulated extract was composed of 35.54% isoflavones, 1.11% flavonoids, 0.06% pterocarpans, ? 0.03% coumarins, and ? 0.03% tyramine. Daidzein, genistein, formononetin, biochanin A, coumestrol and naringenin were estrogenic in the AP assay, and all of these, except formononetin, bound to one or both ERs. Conclusions The major and minor chemical and active estrogenic components of a pre-formulated Phase II red clover clinical extract were identified, quantitatively measured, and the final capsule doses were calculated. The extract is currently under evaluation in a yearlong clinical study for the alleviation of menopausal hot flashes. This is the first report to thoroughly summarize the chemistry and biology of all major peaks observed in the HPLC-UV chromatogram of a clinical red clover dietary supplement.

Booth, Nancy L.; Overk, Cassia R.; Yao, Ping; Burdette, Joanna E.; Nikolic, Dejan; Chen, Shao-Nong; Bolton, Judy L.; van Breemen, Richard B.; Pauli, Guido F.; Farnsworth, Norman R.

2006-01-01

98

CHEMICAL SCREENING OF CHIRATA (SWERTIA CHIRAYITA KARST COLLECTIONS FROM HIMACHAL PREDESH FOR BITTER CONTENT VARIABILITY  

PubMed Central

The investigations were carried out on collations of the herb made from natural habitats with altitudes ranging from 1500 m to 2700m. the material was subjected to chemical screening which revealed a great deal of variation ranging from 0.75 percent to 1.14 per cent wit respect to bitter content which is a pharmaceutically important component of this plant. Besides this observations were also recorded on the effect of root length and root thickness on the yield of bitter principles, observations recorded on soil parameters did not reveal any significant effect on the bitter content production except soil pH.

Dutt, Bhupeder; Srivastava, Latji; Chand, Romosh

1999-01-01

99

Chemical screening of chirata (swertia chirayita karst collections from himachal predesh for bitter content variability.  

PubMed

The investigations were carried out on collations of the herb made from natural habitats with altitudes ranging from 1500 m to 2700m. the material was subjected to chemical screening which revealed a great deal of variation ranging from 0.75 percent to 1.14 per cent wit respect to bitter content which is a pharmaceutically important component of this plant. Besides this observations were also recorded on the effect of root length and root thickness on the yield of bitter principles, observations recorded on soil parameters did not reveal any significant effect on the bitter content production except soil pH. PMID:22556900

Dutt, B; Srivastava, L; Chand, R

1999-01-01

100

Topics in chemical physics: I, Semiclassical reactive scattering theory: II, Corrected effective medium theory  

SciTech Connect

Two distinct areas within theoretical chemical physics are investigated in this dissertation. First, the dynamics of collinear exchange reactions is treated within a semiclassical Gaussian wavepacket (GWP) description. Second, a corrected effective medium (CEM) theory is derived which yields: a one-active-body description of the binding energy between an atom and an inhomogeneous host; and an N-active-body description of the interaction energy for an N atom system. To properly treat the dynamics of collinear exchange reactions, two extensions to the previous methodology of GWP dynamics are presented: evaluation of the interaction picture wavefunction propagators directly via the GWP solution to the time-dependent Schrodinger equation; and use of an expansion of GWPs to represent the initial translational plane wave. This extended GWP dynamical approach is applied to the H + H/sub 2/ collinear exchange reaction using the Porter-Karplus II potential energy surface.

Kress, J.D.

1988-07-01

101

Chemical and biological effects of heavy distillate recycle in the SRC-II process  

SciTech Connect

Recent work from the Merriam Laboratory continuous coal liquefaction units shows that heavy distillate from the SRC-II process can be recycled to extinction, and hence a distillate product boiling entirely below 310/sup 0/C (590/sup 0/F) (or other selected boiling points) is feasible. In these runs distillate yield was not reduced; gas make was unaffected; and hydrogen consumption was increased only slightly, in keeping with the generally higher hydrogen content of lighter end products. Total distillate yield (C/sub 5/-590/sup 0/F) was 56 wt %, MAF coal in runs with subbituminous coal from the Amax Belle Ayr mine. Product endpoint is well below 371/sup 0/C (700/sup 0/F), the temperature above which coal distillates appear to become genotoxic; and the product was shown to be free of mutagenic activity in the Ames test. Chemical analyses showed both the < 270/sup 0/C (< 518/sup 0/F) and the < 310/sup 0/C (< 590/sup 0/F) distillates to be essentially devoid of several reference polycyclic compounds known to be carcinogenic in laboratory animals. Tests for tumorigenic or carcinogenic activity were not carried out on these materials. However, a comparison of chemical data from the Merriam heavy distillate samples with data on the other SRC-II distillates where carcinogenesis or tumorigenesis data is available leads to the expectation that < 371/sup 0/C (< 700/sup 0/F) materials from the Merriam Laboratory will have greatly reduced tumorigenic and carcinogenic activity in skin painting tests. Other studies suggest the product should be more readily upgraded than full-range (C/sub 5/-900/sup 0/F) distillate.

Wilson, B.W.; Pelroy, R.A.; Anderson, R.P.; Freel, J.

1983-12-01

102

Collection method for chemical particulates on surfaces with detection using thermal desorption-ion trap mass spectrometry.  

PubMed

Successful analysis of particulate/low vapor pressure analytes such as explosives and toxic chemicals, and commercial pesticides require new sampling tools that enable detection of these analytes using current vapor phase detection instruments. We describe a sampling approach that uses stainless steel screens coated with a sticky polydimethyl siloxane (PDMS) coating to capture particulates from surfaces. Preliminary results for the collection of dimethyl methylphosphonate (DMMP) sorbed onto silica gel (SG) particulates (DMMP/SG) from a surface with subsequent analysis by thermal desorption-cylindrical ion trap mass spectrometry (TD-CITMS) are reported. PMID:23601282

Ewing, K J; Gibson, D; Sanghera, J; Miklos, F

2013-05-01

103

Solubility classification of airborne uranium products collected at the perimeter of the Allied Chemical Plant, Metropolis, Illinois  

SciTech Connect

Airborne uranium products were collected at the perimeter of the uranium-conversion plant operated by the Allied Chemical Corporation at Metropolis, Illinois, and the dissolution rates of these products were classified in terms of the ICRP Task Group Lung Model. Assignments were based on measurements of the dissolution half-times exhibited by uranium components of the dust samples as they dissolved in simulated lung fluid at 37/sup 0/C. Based on three trials, the dissolution behavior of dust with aerodynamic equivalent diameter (AED) less than 5.5 ..mu..m and collected nearest the closest residence to the plant was classified 0.40 D, 0.60 Y. Based on two trials, the dissolution behavior of dust with AED greater than 5.5 ..mu..m and collected at this location was classified 0.37 D, 0.63 Y. Based on one trial, the dissolution behavior of dust with AED less than 5.5 ..mu..m and collected at a location on the opposite side of the plant was classified 0.68 D, 0.32 Y. There was some evidence for adsorption of dissolved uranium onto other dust components during dissolution, and preliminary dissolution trials are recommended for future samples in order to optimize the fluid replacement schedule.

Kalkwarf, D.R.

1980-05-01

104

Monitoring physical and chemical parameters of Delaware Bay waters with an ERTS-1 data collection platform  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Results of the analysis of data collected during the summer of 1974 demonstrate that the ERTS Data Collection Platform (DCP) is quite responsive to changing water parameters and that this information can be successfully transmitted under all weather conditions. The monitoring of on-site probe outputs reveals a rapid response to changing water temperature, salinity, and turbidity conditions on incoming tides as the tidal salt wedge passes the probe location. The changes in water properties were corroborated by simultaneously sampling the water for subsequent laboratory analysis. Fluctuations observed in the values of salinity, conductivity, temperature and water depth over short time intervals were extremely small. Due to the nature of the probe, 10% to 20% fluctuations were observed in the turbidity values. The use of the average of the values observed during an overpass provided acceptable results. Good quality data was obtained from the satellite on each overpass regardless of weather conditions. Continued use of the DCP will help provide an indication of the accuracy of the probes and transmission system during long term use.

Klemas, V. (principal investigator); Wethe, C.

1975-01-01

105

Arbovirus investigations in Argentina, 1977-1980. II. Arthropod collections and virus isolations from Argentine mosquitoes.  

PubMed

Prospective surveys for arboviruses were carried out in Santa Fe, Corrientes, and Chaco provinces, Argentina, aperiodically during 1977-1980. A total of 313,233 mosquitoes and 598 biting flies other than mosquitoes were collected and tested for virus in 5,197 and 45 pools, respectively. Forty virus strains were isolated, all from mosquitoes, as follows: Santa Fe Province: 4 Gamboa group viruses from Aedeomyia squamipennis, 1 strain each of St. Louis encephalitis virus from Culex pipiens quinquefasciatus and Culex (Culex) spp.; Corrientes Province: a single strain of a newly discovered Anopheles A serogroup virus, Las Maloyas, from Anopheles albitarsis; and Chaco Province: 4 Gamboa group viruses from Ad. squamipennis, 6 strains of new Bunyaviridae (1 Antequera, 1 Barranqueras, and 4 Resistencia) from Culex (Melanoconion) delpontei, 3 strains of a new subtype of western equine encephalitis virus and 1 strain of Para virus from the Cx. (Mel.) ocossa group, 12 strains of a newly discovered subtype (VI) of the Venezuelan equine encephalitis complex from Cx. (Mel.) delpontei, and 1 strain each from Ad. squamipennis, Aedes scapularis, Ae. spp., Cx. (Cux.) spp., Cx. (Mel.) ocossa group, Mansonia spp., and Psorophora spp. Bloodmeals from 265 engorged mosquitoes were identified by precipitin test. These data, coupled with data on engorgement rates for 25,995 mosquitoes from bait collections, provide information on the host feeding patterns of several mosquito species. This information is discussed, along with data on relative abundance of mosquito species, within the context of the vector relationships of the species from which viruses were isolated. The association of Cx. (Mel.) delpontei with 18 strains of 4 different viruses in Chaco Province, plus its catholic feeding habits, clearly indicate for the first time the importance of this species as an arbovirus vector. PMID:2863989

Mitchell, C J; Monath, T P; Sabattini, M S; Cropp, C B; Daffner, J F; Calisher, C H; Jakob, W L; Christensen, H A

1985-09-01

106

Chemical fingerprinting of petroleum biomarkers in Deepwater Horizon oil spill samples collected from Alabama shoreline.  

PubMed

We compare the chromatographic signatures of petroleum biomarkers in Deepwater Horizon (DH) source oil, three other reference crude oils, DH emulsified mousse that arrived on Alabama's shoreline in June 2010, and seven tar balls collected from Alabama beaches from 2011 to 2012. Characteristic hopane and sterane fingerprints show that all the tar ball samples originated from DH oil. In addition, the diagnostic ratios of various hopanes indicate an excellent match. Quantitation data for C????-hopane concentration levels show that most of the weathering observed in DH-related tar balls found on Alabama's beaches is likely the result of natural evaporation and dissolution that occurred during transport across the Gulf of Mexico prior to beach deposition. Based on the physical and biomarker characterization data presented in this study we conclude that virtually all fragile, sticky, brownish tar balls currently found on Alabama shoreline originated from the DH oil spill. PMID:23523118

Mulabagal, V; Yin, F; John, G F; Hayworth, J S; Clement, T P

2013-05-15

107

Microbial production of isotopically light iron(II) in a modern chemically precipitated sediment and implications for isotopic variations in ancient rocks.  

PubMed

The inventories and Fe isotope composition of aqueous Fe(II) and solid-phase Fe compounds were quantified in neutral-pH, chemically precipitated sediments downstream of the Iron Mountain acid mine drainage site in northern California, USA. The sediments contain high concentrations of amorphous Fe(III) oxyhydroxides [Fe(III)(am)] that allow dissimilatory iron reduction (DIR) to predominate over Fe-S interactions in Fe redox transformation, as indicated by the very low abundance of Cr(II)-extractable reduced inorganic sulfur compared with dilute HCl-extractable Fe. delta(56)Fe values for bulk HCl- and HF-extractable Fe were approximately 0. These near-zero bulk delta(56)Fe values, together with the very low abundance of dissolved Fe in the overlying water column, suggest that the pyrite Fe source had near-zero delta(56)Fe values, and that complete oxidation of Fe(II) took place prior to deposition of the Fe(III) oxide-rich sediment. Sediment core analyses and incubation experiments demonstrated the production of millimolar quantities of isotopically light (delta(56)Fe approximately -1.5 to -0.5 per thousand) aqueous Fe(II) coupled to partial reduction of Fe(III)(am) by DIR. Trends in the Fe isotope composition of solid-associated Fe(II) and residual Fe(III)(am) are consistent with experiments with synthetic Fe(III) oxides, and collectively suggest an equilibrium Fe isotope fractionation between aqueous Fe(II) and Fe(III)(am) of approximately -2 per thousand. These Fe(III) oxide-rich sediments provide a model for early diagenetic processes that are likely to have taken place in Archean and Paleoproterozoic marine sediments that served as precursors for banded iron formations. Our results suggest pathways whereby DIR could have led to the formation of large quantities of low-delta(56)Fe minerals during BIF genesis. PMID:20374296

Tangalos, G E; Beard, B L; Johnson, C M; Alpers, C N; Shelobolina, E S; Xu, H; Konishi, H; Roden, E E

2010-06-01

108

Microbial production of isotopically light iron(II) in a modern chemically precipitated sediment and implications for isotopic variations in ancient rocks  

USGS Publications Warehouse

The inventories and Fe isotope composition of aqueous Fe(II) and solid-phase Fe compounds were quantified in neutral-pH, chemically precipitated sediments downstream of the Iron Mountain acid mine drainage site in northern California, USA. The sediments contain high concentrations of amorphous Fe(III) oxyhydroxides [Fe(III)am] that allow dissimilatory iron reduction (DIR) to predominate over Fe–S interactions in Fe redox transformation, as indicated by the very low abundance of Cr(II)-extractable reduced inorganic sulfur compared with dilute HCl-extractable Fe. ?56Fe values for bulk HCl- and HF-extractable Fe were ? 0. These near-zero bulk ?56Fe values, together with the very low abundance of dissolved Fe in the overlying water column, suggest that the pyrite Fe source had near-zero ?56Fe values, and that complete oxidation of Fe(II) took place prior to deposition of the Fe(III) oxide-rich sediment. Sediment core analyses and incubation experiments demonstrated the production of millimolar quantities of isotopically light (?56Fe ? -1.5 to -0.5?) aqueous Fe(II) coupled to partial reduction of Fe(III)am by DIR. Trends in the Fe isotope composition of solid-associated Fe(II) and residual Fe(III)am are consistent with experiments with synthetic Fe(III) oxides, and collectively suggest an equilibrium Fe isotope fractionation between aqueous Fe(II) and Fe(III)am of approximately -2?. These Fe(III) oxide-rich sediments provide a model for early diagenetic processes that are likely to have taken place in Archean and Paleoproterozoic marine sediments that served as precursors for banded iron formations. Our results suggest pathways whereby DIR could have led to the formation of large quantities of low-?56Fe minerals during BIF genesis.

Tangalos, G. E.; Beard, B. L.; Johnson, C. M.; Alpers, C. N.; Shelobolina, E. S.; Xu, H.; Konishi, H.; Roden, E. E.

2012-01-01

109

Divergent Chemical Cues Elicit Seed Collecting by Ants in an Obligate Multi-Species Mutualism in Lowland Amazonia  

PubMed Central

In lowland Amazonian rainforests, specific ants collect seeds of several plant species and cultivate them in arboreal carton nests, forming species-specific symbioses called ant-gardens (AGs). In this obligate mutualism, ants depend on the plants for nest stability and the plants depend on ant nests for substrate and nutrients. AG ants and plants are abundant, dominant members of lowland Amazonian ecosystems, but the cues ants use to recognize the seeds are poorly understood. To address the chemical basis of the ant-seed interaction, we surveyed seed chemistry in nine AG species and eight non-AG congeners. We detected seven phenolic and terpenoid volatiles common to seeds of all or most of the AG species, but a blend of the shared compounds was not attractive to the AG ant Camponotus femoratus. We also analyzed seeds of three AG species (Anthurium gracile, Codonanthe uleana, and Peperomia macrostachya) using behavior-guided fractionation. At least one chromatographic fraction of each seed extract elicited retrieval behavior in C. femoratus, but the active fractions of the three plant species differed in polarity and chemical composition, indicating that shared compounds alone did not explain seed-carrying behavior. We suggest that the various AG seed species must elicit seed-carrying with different chemical cues.

Youngsteadt, Elsa; Guerra Bustios, Patricia; Schal, Coby

2010-01-01

110

Chemical variability of groundwater samples collected from a coal seam gas exploration well, Maramarua, New Zealand.  

PubMed

A pilot study has produced 31 groundwater samples from a coal seam gas (CSG) exploration well located in Maramarua, New Zealand. This paper describes sources of CSG water chemistry variations, and makes sampling and analytical recommendations to minimize these variations. The hydrochemical character of these samples is studied using factor analysis, geochemical modelling, and a sparging experiment. Factor analysis unveils carbon dioxide (CO(2)) degassing as the principal cause of sample variation (about 33%). Geochemical modelling corroborates these results and identifies minor precipitation of carbonate minerals with degassing. The sparging experiment confirms the effect of CO(2) degassing by showing a steady rise in pH while maintaining constant alkalinity. Factor analysis correlates variations in the major ion composition (about 17%) to changes in the pumping regime and to aquifer chemistry variations due to cation exchange reactions with argillaceous minerals. An effective CSG water sampling program can be put into practice by measuring pH at the wellhead and alkalinity at the laboratory; these data can later be used to calculate the carbonate speciation at the time the sample was collected. In addition, TDS variations can be reduced considerably if a correct drying temperature of 180 °C is consistently implemented. PMID:23199455

Taulis, Mauricio; Milke, Mark

2013-03-01

111

Chemical characterization of fog and rain water collected at the eastern Andes cordillera  

NASA Astrophysics Data System (ADS)

During a three month period in 2003 and 2004, the chemistry of fog and rainwater were studied at the "El Tiro" site in a tropical mountain forest ecosystem in Ecuador, South America. The fogwater samples were collected using a passive fog collector, and for the rain water, a standard rain sampler was employed. For all samples, electric conductivity, pH, and the concentrations of NH4+, K+, Na+, Ca2+, Mg2+, Cl-, NO3-, PO43-, and SO42-, were measured. For each fog sample, a 5 day back trajectory was calculated by the use of the HYSPLIT model. Two types of trajectories occurred. One type was characterized by advection of air masses from the East over the Amazonian basin, the other trajectory arrived one from the West after significant travel time over the Pacific Ocean. We found considerably higher ion concentrations in fogwater samples than in rain samples. Median pH values are 4.58 for fog water, and 5.26 for the rain samples, respectively. The median electric conductivity was 23 µS cm-1 for the fog and 6 µS cm-1 for the rain. The concentrations of all analysed ions were relatively low compared to other mountainous sites (Weathers et al., 1988; Elias et al., 1995; Schemenauer et al., 1995; Wrzesinsky and Klemm, 2000; Zimmermann and Zimmermann, 2002). The continent samples exhibit higher concentrations of most ions as compared to the pacific samples.

Beiderwieden, E.; Wrzesinsky, T.; Klemm, O.

2005-06-01

112

Hygroscopic and Chemical Properties of Aerosols collected near a Copper Smelter: Implications for Public and Environmental Health  

PubMed Central

Particulate matter emissions near active copper smelters and mine tailings in the southwestern United States pose a potential threat to nearby environments owing to toxic species that can be inhaled and deposited in various regions of the body depending on the composition and size of the particles, which are linked by particle hygroscopic properties. This study reports the first simultaneous measurements of size-resolved chemical and hygroscopic properties of particles next to an active copper smelter and mine tailings by the towns of Hayden and Winkelman in southern Arizona. Size-resolved particulate matter samples collected near an active copper smelter were examined with inductively coupled plasma mass spectrometry, ion chromatography, and a humidified tandem differential mobility analyzer. Aerosol particles collected at the measurement site are enriched in metals and metalloids (e.g. arsenic, lead, and cadmium) and water-uptake measurements of aqueous extracts of collected samples indicate that the particle diameter range of particles most enriched with these species (0.18–0.55 µm) overlaps with the most hygroscopic mode at a relative humidity of 90% (0.10–0.32 µm). These measurements have implications for public health, microphysical effects of aerosols, and regional impacts owing to the transport and deposition of contaminated aerosol particles.

Sorooshian, Armin; Csavina, Janae; Shingler, Taylor; Dey, Stephen; Brechtel, Fred J.; Saez, A. Eduardo; Betterton, Eric A.

2012-01-01

113

Chemical and statistical interpretation of sized aerosol particles collected at an urban site in Thessaloniki, Greece.  

PubMed

The size distribution of aerosol particles (PM0.015-PM18) in relation to their soluble inorganic species and total water soluble organic compounds (WSOC) was investigated at an urban site of Thessaloniki, Northern Greece. The sampling period was from February to July 2007. The determined compounds were compared with mass concentrations of the PM fractions for nano (N: 0.015 < Dp < 0.06), ultrafine (UFP: 0.015 < Dp < 0.125), fine (FP: 0.015 < Dp < 2.0) and coarse particles (CP: 2.0 < Dp < 8.0) in order to perform mass closure of the water soluble content for the respective fractions. Electrolytes were the dominant species in all fractions (24-27%), followed by WSOC (16-23%). The water soluble inorganic and organic content was found to account for 53% of the nanoparticle, 48% of the ultrafine particle, 45% of the fine particle and 44% of the coarse particle mass. Correlations between the analyzed species were performed and the effect of local and long-range transported emissions was examined by wind direction and backward air mass trajectories. Multivariate statistical analysis (cluster analysis and principal components analysis) of the collected data was performed in order to reveal the specific data structure. Possible sources of air pollution were identified and an attempt is made to find patterns of similarity between the different sized aerosols and the seasons of monitoring. It was proven that several major latent factors are responsible for the data structure despite the size of the aerosols - mineral (soil) dust, sea sprays, secondary emissions, combustion sources and industrial impact. The seasonal separation proved to be not very specific. PMID:24007436

Tsitouridou, Roxani; Papazova, Petia; Simeonova, Pavlina; Simeonov, Vasil

2013-01-01

114

Variations of chemical components in fossil corals collected from Tahiti by IODP Expedition 310  

NASA Astrophysics Data System (ADS)

Integrated Ocean Drilling Program (IODP) Expedition 310 to the reef terraces around Tahiti, French Polynesia was conducted for the purpose of establishing the course of postglacial sea level rise at Tahiti and to define sea-surface temperature (SST) and marine environmental variation for the region over the period 20-10 ka. While sea-level during the Last Glacial Maximum (LGM) has been observed as much as ca. 130 m below its present value for sites remote from former ice sheet (far-field sites), fossil coral records contain evidence of a dramatic sea level rise in excess 20 m within the last deglaciation around 14 ka, termed meltwater pulse 1A (mwp-1A). Although this event would have had a significant effect on global climate, the relationship between mwp-1A and the climate system remains a subject of debate. Coral geochemistry has a potential as proxies for marine environments, and in this study we measured trace elements, such as Ba, U and Cd, in addition to Pb isotope ratios in fossil Porites sp. collected around Tahiti in order to reconstruct SST, upwelling and/or wind source/direction. Skeletal conditions of fossil corals were investigated using X-ray diffraction and we selected samples composed of only aragonite. Dating of fossil corals were determined based on 14C method by accelerator mass spectrometry. As a result, approximately 10 samples were from before and in the period of mwp-1A event (15 - 14 ka). Then bulk samples were taken from all coral specimens by a milling machine and trace elements and Pb isotopic compositions in bulk samples were analyzed by inductively coupled mass spectrometer (ICP-MS) and multiple-collector ICP-MS, respectively. Data of Pb isotope ratios in fossil corals were comparable with those from crust in the Central Andes, suggesting that easterly wind was predominant around Tahiti with a slight variation depending on the age. We will also discuss the relationship between upwelling and climate condition around the mwp-1A based on Cd contents and U/Ca ratios.

Inoue, M.; Harada, M.; Suzuki, A.; Tanimizu, M.; Tokoyama, Y.

2008-12-01

115

Chemical composition of rainwater collected at a southwest site of Mexico City, Mexico  

NASA Astrophysics Data System (ADS)

Measurements of the trace metals Cd, Cr, Mn, Ni, Pb, V and Al in soluble and insoluble rain fractions and SO 4- 2 , NO 3-, Cl -, HCO 3-, Ca 2+, Mg 2+, Na +, K +, NH 4+ and H + in soluble fractions were performed in rainwater collected at a southwest site of Mexico City during the rainy seasons of 2001 and 2002. Aluminum presented the highest volume-weighted mean concentration (VWMC) in both insoluble and soluble fractions. In the insoluble fractions, the VWM of the other trace metals decreased in the order Mn, Pb, Ni, V, Cr and Cd, and in the soluble fractions in the order Mn, V, Ni, Pb, Cd and Cr. Ammonium presented the higher VWMC, followed by SO 42-, NO 3-, HCO 3-, Ca 2+, Cl -, H +, Na +, Mg 2+ and K +. Air mass back trajectories were associated to the concentrations of trace metals and of SO 42-, Ca 2+, Mg 2+, NH 4+ and H + observed during each rainy day. Trace metal concentrations were not clearly related to wind direction. Enrichment factors related to the relative abundance of elements in crustal material were calculated using Mg as reference. The high enrichment factors (EF c) suggested that, in general, trace metals and major ions had an anthropogenic origin. Aluminum, K +, and Ca 2+ were the only elements that had a significant crustal source. Factor analysis (Principal Component Analysis) with Varimax normalized rotation grouping the elements analyzed into three factors. Factor 1 indicated a crustal contribution for Ca 2+, K +, Mg 2+ and anthropogenic sources for SO 42-, NH 4+ and V. Factor 2 indicated a high loading for Al, Ni and Mn, that indicate possible contribution of anthropogenic sources but with a significant crustal contribution for Al. Factor 3 indicated an anthropogenic origin for H + and NO 3-. Pearson's correlations show that Al correlated with all the metals, including Ca 2+ and Mg 2+. The solubility of trace metals did not depend on rainwater pH. As it was expected, Al presented the highest wet deposition flux.

Báez, A.; Belmont, R.; García, R.; Padilla, H.; Torres, M. C.

2007-10-01

116

Cytotoxic activity and chemical reactivity of cis-platinum(II) and trans-palladium(II) complexes with diethyl (pyridinylmethyl)phosphates.  

PubMed

A series of square-planar platinum(II) and palladium(II) complexes of the formula cis-[PtCl2L2] and trans-[PdCl2L2] [L stands for diethyl (pyridin-2-ylmethyl)phosphate (2-pmOpe) or diethyl (pyridin-3-ylmethyl)phosphate (3-pmOpe) or diethyl (pyridin-4-ylmethyl)phosphate (4-pmOpe)] have been synthesized and tested in vitro for their cytotoxicity against mouse leukemia L1210 cells. The results indicated that the cis-platinum complexes showed superior activity than trans-palladium complexes, but lower in comparison to cisplatin. The chemical reactivity of the tested complexes has been determined in an in vitro NBP test. The platinum complexes exhibited very high chemical reactivity in NBP test, higher than cisplatin. The results showed no correlation between cytotoxicity and chemical reactivity for platinum complexes. Two platinum(II) complexes {cis-[PtCl2(2-pmOpe)2], cis-[PtCl2(3-pmOpe)2]} have been synthesized and characterized by IR, 1H NMR, 31P NMR, and elemental analysis. PMID:18586354

Kalinowska-Lis, Urszula; Szmigiero, Leszek; Studzian, Kazimierz; Ochocki, Justyn

2009-02-01

117

Chemical Characterization and Removal of Carbon-14 from Irradiated Graphite II - 13023  

SciTech Connect

Approximately 250,000 tonnes of irradiated graphite waste exists worldwide and that quantity is expected to increase with decommissioning of Generation II reactors and deployment of Generation IV gas-cooled, graphite moderated reactors. This situation indicates the need for a graphite waste management strategy. Of greatest concern for long-term disposal of irradiated graphite is carbon-14 (C-14), with a half-life of 5730 years. Study of irradiated graphite from some nuclear reactors indicates C-14 is concentrated on the outer 5 mm of the graphite structure. The aim of the research presented last year and updated here is to identify the chemical form of C-14 in irradiated graphite and develop a practical method by which C-14 can be removed. A nuclear-grade graphite, NBG-18, and a high-surface-area graphite foam, POCOFoam{sup R}, were exposed to liquid nitrogen (to increase the quantity of C-14 precursor) and neutron-irradiated (10{sup 13} neutrons/cm{sup 2}/s). Finer grained NBG-25 was not exposed to liquid nitrogen prior to irradiation at a neutron flux on the order of 10{sup 14} /cm{sup 2}/s. Characterization of pre- and post-irradiation graphite was conducted to determine the chemical environment and quantity of C-14 and its precursors via the use of surface sensitive characterization techniques. Scanning Electron Microscopy (SEM) was used to evaluate the morphological features of graphite samples. The concentration, chemical composition, and bonding characteristics of C-14 and its precursors were determined through X-ray Photoelectron Spectroscopy (XPS), Time-of-Flight Secondary Ion Mass Spectrometry (SIMS), and Energy Dispersive X-ray Analysis Spectroscopy (EDX). Results of post-irradiation characterization of these materials indicate a variety of surface functional groups containing carbon, oxygen, nitrogen and hydrogen. During thermal treatment, irradiated graphite samples are heated in the presence of an inert carrier gas (with or without oxidant gas), which carries off gaseous products released during treatment. Graphite gasification occurs via interaction with adsorbed oxygen complexes. Experiments in argon were performed at 900 deg. C and 1400 deg. C to evaluate the selective removal of C-14. Thermal treatment also was performed with the addition of 3 and 5 volume % oxygen at temperatures 700 deg. C and 1400 deg. C. Thermal treatment experiments were evaluated for the effective selective removal of C-14. Lower temperatures and oxygen levels correlated to more efficient C-14 removal. (authors)

Dunzik-Gougar, Mary Lou; Cleaver, James; LaBrier, Daniel; McCrory, Shilo; Smith, Tara E. [Idaho State University: 1776 Science Center Dr., Idaho Falls, ID, 83401 (United States)] [Idaho State University: 1776 Science Center Dr., Idaho Falls, ID, 83401 (United States)

2013-07-01

118

Possible Role of Metal(II) Octacyanomolybdate(IV) in Chemical Evolution: Interaction with Ribose Nucleotides  

NASA Astrophysics Data System (ADS)

We have proposed that double metal cyanide compounds (DMCs) might have played vital roles as catalysts in chemical evolution and the origin of life. We have synthesized a series of metal octacyanomolybdates (MOCMos) and studied their interactions with ribose nucleotides. MOCMos have been shown to be effective adsorbents for 5'-ribonucleotides. The maximum adsorption level was found to be about 50 % at neutral pH under the conditions studied. The zinc(II) octacyanomolybdate(IV) showed larger adsorption compared to other MOCMos. The surface area seems to important parameter for the adsorption of nucleotides. The adsorption followed a Langmuir adsorption isotherms with an overall adsorption trends of the order of 5'-GMP > 5'-AMP > 5'-CMP > 5'-UMP. Purine nucleotides were adsorbed more strongly than pyrimidine nucleotides on all MOCMos possibly because of the additional binding afforded by the imidazole ring in purines. Infrared spectral studies of adsorption adducts indicate that adsorption takes place through interaction between adsorbate molecules and outer divalent ions of MOCMos.

Kumar, Anand; Kamaluddin

2013-02-01

119

New chemical models of enzymatic oxidation. II. Oxidation of alcohols to acids, catalyzed by Cu(II) complexes  

SciTech Connect

It was established that complex compounds of Cu(II) catalyze the oxidation of primary alcohols to acids in the presence of bases; in aqueous media n-propanol is oxidized primarily to formic acid; in anhydrous media n-propanol and benzyl alcohol are capable of being oxidized to propionic and benzoic acids, respectively. It was shown that acids are the primary reaction products, and they are formed as a result of the attack of anions coordinated on Cu(II) sites by molecular oxygen.

Sakharov, A.M.; Skibida, I.P.

1988-07-01

120

Synthesis and Physico?Chemical Studies on Iron(II,III,III) and Cobalt(II) Thiocarboxylates  

Microsoft Academic Search

A series of iron(II,III,III) and cobalt(II) complexes of thiocarboxylic acids of the general formulas [FeFe2 O(SOCR)6(L)3] and [Co(SOCR)2(L)2] (R = C2H5 or C(CH3)3 and L = EtOH or py) have been synthesized and characterized by elemental and thermogravimetric analyses, spectral (infrared, electronic, and Mössbauer) studies, molar conductance, magnetic susceptibility, and molecular weight determinations. The electronic spectral data suggested an octahedral environment around the metal

B. P. Baranwal; Tarkeshwar Gupta

2004-01-01

121

Synthesis, characterization and chemical properties of 1-((E)-2-pyridinylmethylidene)semicarbazone manganese(II) and iron(II) complexes  

NASA Astrophysics Data System (ADS)

Manganese(II) perchlorate and iron(II) chloride react with 2-formylpyridine semicarbazone (HCSpy) in boiling ethanol to produce [Mn II(HSCpy) 2](ClO 4) 2·C 2H 5OH and [Fe IICl(HSCpy)]Cl. The distorted octahedral manganese complex crystallizes in the triclinic system with space group P(-1). The ligand HSCpy is tridentate and is coordinated through two nitrogen and one oxygen atoms. Comparison of the bond distances with analogous transition metal complexes that have the same geometry revealed longer bonds for the manganese derivative, an outcome that correlates well with the radius of the metal ions. The iron(II) ion is tetracoordinated to one semicarbazone and one chloride. Mass spectrometry, conductivity measurements, Mössbauer, UV-VIS, FTIR and elemental analysis were all in accordance with the proposed composition and the plausible geometry of [FeCl(HSCpy)]Cl. Mass spectrometry unequivocally detected the presence of the [FeCl(HSCpy)] + ion with a m/ z of 254.97 and intensity of 2 × 10 5.

Garbelini, Ellery Regina; Martin, Maria da Graça M. B.; Back, Davi Fernando; Evans, David John; Müller-Santos, Marcelo; Ribeiro, Ronny Rocha; Lang, Ernesto Schulz; Nunes, Fábio Souza

2012-01-01

122

West Hackberry Strategic Petroleum Reserve site brine-disposal monitoring, Year I report. Volume II. Physical and chemical oceanography. Final report  

SciTech Connect

This project centers around the Strategic Petroleum Site (SPR) known as the West Hackberry salt dome which is located in southwestern Louisiana, and which is designed to store 241 million barrels of crude oil. Oil storage caverns are formed by injecting water into salt deposits, and pumping out the resulting brine. Studies described in this report were designed as follow-on studies to three months of pre-discharge characterization work, and include data collected during the first year of brine leaching operations. The objectives were to: (1) characterize the environment in terms of physical, chemical and biological attributes; (2) determine if significant adverse changes in ecosystem productivity and stability of the biological community are occurring as a result of brine discharge; and (3) determine the magnitude of any change observed. Contents of Volume II include: introduction; physical oceanography; estuarine hydrology and hydrography; analysis of discharge plume; and water and sediment quality.

DeRouen, L.R.; Hann, R.W.; Casserly, D.M.; Giammona, C.; Lascara, V.J. (eds.)

1983-02-01

123

(1)H, (13)C, and (15)N chemical shifts assignments for human endothelial monocyte-activating polypeptide EMAP II.  

PubMed

Endothelial and monocyte-activating polypeptide II (EMAP II) is a cytokine that plays an important role in inflammation, apoptosis and angiogenesis processes in tumour tissues. Structurally, the EMAP II is a 169 amino acid residues long C-terminal domain (residues 147-312) of auxiliary tRNA binding protein p43. In spite of existence in pdb databank of two X-ray structures there are some important aspects of EMAP II cytokine function which are still not fully understood in detail. To obtain information about 3D structure and backbone dynamic processes in solution we perform structure evaluation of human EMAP II cytokine by NMR spectroscopy. The standard approach to sequence-specific backbone assignment using 3D NMR data sets was not successful in our studies and was supplemented by recently developed 4D NMR experiments with random sampling of evolution time space. Here we report the backbone and side chain (1)H, (13)C, and (15)N chemical shifts in solution for recombinant EMAP II cytokine together with secondary structure provided by TALOS + software. PMID:22392337

Lozhko, Dmytro; Stanek, Jan; Kazimierczuk, Krzysztof; Zawadzka-Kazimierczuk, Anna; Kozminski, Wiktor; Zhukov, Igor; Kornelyuk, Alexander

2013-04-01

124

Temporal variability in 20 chemical elements content of Parasol Mushroom (Macrolepiota procera) collected from two sites over a few years.  

PubMed

Mature specimens of Parasol Mushroom were collected annually in the outskirts of the Siemiany (2000-2003) and Rafa (2001-2003) sites in the northern part of Poland to examine temporal variations and similarities in the composition of 20 chemical elements. Analysis was done under the same condition and using well-validated analytical methods. Elements were determined by inductively coupled plasma-atomic emission spectroscopy and cold vapour-atomic absorption spectroscopy (Hg). The ranges of Ag, Al, Ba, Ca, Cd, Co, Cu, Cr, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr and Zn concentrations in the caps of fruiting bodies were similar (p > 0.05; Mann-Whitney U test) for both geographically distant sites, and these specimens from Rafa were more contaminated with Pb (p < 0.05; Mann-Whitney U test). The annual collections of caps in the Siemiany site varied in Ag, Al, Ba, Ca, Cd, Co, Cu, Fe, Hg, Na, Rb and Sr and contents (0.05 < p < 0.001), while they were similar in Cr, K, Mg, Mn, Ni, P, Pb and Zn (p > 0.05; Mann-Whitney U test). The annual collections of specimens from the Rafa site varied in contents of Ag, Al, Ba, Ca, Fe, Hg, K, Mg, Mn, P, Rb and Zn (p > 0.05), while they were similar in Cd, Co, Cr, Cu, Na, Ni, Pb and Sr (p < 0.05). The results of this study imply that metallic elements content of Parasol Mushroom collected at the same undisrupted sites, and hence keeping the same geochemical condition for mushroom development and fructification (the same stands and probably the same mycelia), can fluctuate over the years or the life-span of mycelium. Hence, when assessing the nutritional value of essential metallic elements and status of non-essential or toxic metallic elements in Parasol's Mushroom caps (and probably also of other mushrooms species) to man, the possible fluctuation in contents over time have to be taken into account. PMID:22251207

Gucia, Magdalena; Jarzy?ska, Gra?yna; Kojta, Anna K; Falandysz, Jerzy

2012-01-01

125

Accessibility of selenomethionine proteins by total chemical synthesis: structural studies of human herpesvirus-8 MIP-II.  

PubMed

The determination of high resolution three-dimensional structures by X-ray crystallography or nuclear magnetic resonance (NMR) is a time-consuming process. Here we describe an approach to circumvent the cloning and expression of a recombinant protein as well as screening for heavy atom derivatives. The selenomethionine-modified chemokine macrophage inflammatory protein-II (MIP-II) from human herpesvirus-8 has been produced by total chemical synthesis, crystallized, and characterized by NMR. The protein has a secondary structure typical of other chemokines and forms a monomer in solution. These results indicate that total chemical synthesis can be used to accelerate the determination of three-dimensional structures of new proteins identified in genome programs. PMID:9877169

Shao, W; Fernandez, E; Wilken, J; Thompson, D A; Siani, M A; West, J; Lolis, E; Schweitzer, B I

1998-12-11

126

The promising chemical kinetics for the simulation of propane-air combustion with KIVA-II code  

NASA Technical Reports Server (NTRS)

The development of chemical kinetics for the simulation of propane-air combustion with the use of computer code KIVA-II since 1989 is summarized here. In order to let readers understand the general feature well, a brief description of the KIVA-II code, specially related with the chemical reactions is also given. Then the results of recent work with 20 reaction mechanism is presented. It is also compared with the 5 reaction mechanism. It may be expected that the numerical stability of the 20 reaction mechanism is better as compared to that of 5 reaction mechanism, but the CPU time of the CRAY computer is much longer. Details are presented in the paper.

Ying, S. J.; Gorla, Rama S. R.; Kundu, Krishna P.

1993-01-01

127

Modeling Electron Transfer in Biochemistry:  A Quantum Chemical Study of Charge Separation in Rhodobacter s phaeroides and Photosystem II  

Microsoft Academic Search

High-level quantum chemical methods (hybrid density-functional type) are applied to the light- driven charge-separation process in the photosynthetic reaction centers of both bacteria and photosystem II in green plants. Structural information on the bacterial system provides the basis for choosing the models used in the calculations. The energetics of the electron transfer from the (bacterio)chlorophyll to the quinone are calculated

Margareta R. A. Blomberg; Per E. M. Siegbahn; Gerald T. Babcock

1998-01-01

128

Sequence-dependent reactivity of linear DNA to chemical cleavage by Cu(II):thiol combinations including cysteine or glutathione.  

PubMed Central

The chemical cleavage of linear DNA by Cu(II):thiol combinations was investigated using end-labelled double-stranded restriction fragments. Single-strand cleavage of the target DNA occurred with apparent sequence preference, but there appeared to be no apparent consensus sequence for such preferentially cleaved sites based on studies of three different restriction fragments. For any given restriction fragment, the observed Cu(II):thiol DNA-cleavage sequence preference was found to be independent of the nature of the thiol used. Cleavage of 3'-end-labelled DNA generated fragments bearing 5'-phosphoryl termini, and cleavage of 5'-end-labelled DNA gave rise to fragments bearing 3'-phosphoryl and 3'-'phosphatase-inert' termini in equal proportions. No appreciable amounts of fragments bearing 3'- or 5'-hydroxy termini were detected. This pattern of cleavage products is similar to that observed using the hydroxyl-radical-generating systems, 60Co gamma-irradiation or methidium propyl EDTA:Fe(II), but is dissimilar to that found with the Cu(II):phenanthroline or bleomycin systems. Cu(II):thiol cleavage of DNA fragments containing inserts of repeated dinucleotide sequence showed alternating patterns of relative cleavage intensities within the insert-sequence regions which were not seen in the sequences flanking the insert sequence. The assembled experimental data indicate that a reaction product of the Cu(II):thiol interaction, probably the hydroxyl radical, causes DNA cleavage. The Cu(II):thiol interaction may occur free in solution or via a copper species which is bound non-specifically to DNA. The observed low sequence-dependence of the cleavage reaction probably reflects the nature of the DNA structure itself, the Cu(II):thiol system serving as a structural probe of sequence-dependent structural variations in the DNA structure. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

John, D C; Douglas, K T

1993-01-01

129

Screening of novel chemical compounds as possible inhibitors of carbonic anhydrase and photosynthetic activity of photosystem II.  

PubMed

Thirty novel chemical compounds were designed and synthesized expecting that they would be possible inhibitors. From this number eleven were organic bases, twenty-four were their organic derivatives and fourteen were metal complexes. Screening of these chemicals by their action on photosynthetic electron transfer (PET) and carbonic anhydrase (CA) activity (CAA) of photosystem II (PSII), ?-CA, as well as ?-CA was done. Several groups were revealed among them. Some of them are capable to suppress either one, two, three, or even all of the measured activities. As example, one of the Cu(II)-phenyl sulfonylhydrazone complexes (compound 25) suppresses CAA of ?-CA by 88%, CAA of ?-CA by 100% inhibition; CAA of PSII by 100% and the PSII photosynthetic activity by 66.2%. The Schiff base compounds (12, 15) and Cu(II)-phenyl sulfonylhydrazone complexes (25, 26) inhibited the CAA and PET of PSII significantly. The obtained data indicate that the PSII donor side is a target of the inhibitory action of these agents. Some physico- or electrochemical properties such as diffusion coefficient, number of transferred electrons, peak potential and heterogeneous standard rate constants of the compounds were determined in nonaqueous media. pKa values were also determined in nonaqueous and aqueous media. Availability in the studied group of novel chemical agents possessing different inhibitory activity allow in future to isolate the "active part" in the structure of the inhibitors responsible for different inhibitory mechanisms, as well as to determine the influence of side substituters on its inhibitory efficiency. PMID:24418071

Karacan, Mehmet Say?m; Zharmukhamedov, Sergei K; Mama?, Serhat; Kupriyanova, Elena V; Shitov, Alexandr V; Klimov, Vyacheslav V; Ozbek, Neslihan; Ozmen, Ummühan; Gündüzalp, Ayla; Schmitt, Franz-Josef; Karacan, Nurcan; Friedrich, Thomas; Los, Dmitry A; Carpentier, Robert; Allakhverdiev, Suleyman I

2014-08-01

130

Physical-Chemical Treatment of a Municipal Wastewater Using Powdered Carbon. No. II.  

National Technical Information Service (NTIS)

Salt Lake City municipal wastewater was treated in a nominal 100 gpm pilot plant by chemical coagulation-precipitation, powdered activated carbon adsorption and granular media filtration. Chemical-primary sludge was gravity thickened and vacuum filter dew...

D. E. Burns D. J. Cook R. N. Wallace

1976-01-01

131

Solubility classification of airborne uranium products collected at the perimeter of the Allied Chemical Plant, Metropolis, Illinois  

SciTech Connect

The purpose of this study was to collect airborne uranium products at the perimeter of the uranium-conversion plant operated by the Allied Chemical Corporation at Metropolis, Illinois, and to classify the dissolution rates of these products in terms of the ICRP Task Group Lung Model. The International Commission on Radiological Protection developed this model for use in computing the radiation dose from radionuclides deposited in the lung. A key parameter is the classification of the deposited material according to the rate at which it leaves the lung. Three classes were established: D, W, and Y, corresponding to half-times in the lung of 0 to 10 days, 11 to 100 days, and > 100 days, respectively. If clearance of the material from the lung is not strictly exponential with time, it is approximated by a sum of exponentials; and the material is classified according to the fractions of D, W, and Y components. Assignments were based on measurements of the dissolution half-times exhibited by uranium components of the dust samples as they dissolved in simulated lung fluid at 37C. Although endocytosis and ciliary-mucus transport are known to contribute to lung clearance, experiments have indicated that a few days after dust deposition, dissolution determines the clearance rate for the lower respiratory tract.

Kalkwarf, D.R.

1980-06-01

132

Summary of selected data on chemical contaminants in sediments collected during 1984, 1985, 1986, and 1987. Technical memo  

SciTech Connect

Since 1984, the National Oceanic and Atmospheric Administration's (NOAA) National Status and Trends (NS T) Program has analyzed samples of surface sediment collected at about 200 coastal and estuarine sites throughout the United States. The chemical contaminants measured are chlorinated pesticides, polychlorinated biphenyls (PCSs), polyaromatic hydrocarbons (PAHs), and 12 trace elements. Sediment characteristics such as grain size, which affect contaminant concentrations, have also been quantified. With few exceptions, the higher levels of contamination have been found among the 175 sites where the sediment is muddy rather than sandy. Most of the highest concentrations for any particular contaminant have been at the 20 sites near Boston, New York, San Diego, Los Angeles, or Seattle. Despite being sandy, sediments at two Long Island Sound sites showed high levels of PAHs. Except for some sites near the Florida cities of Jacksonville, Tampa, Panama City, and Ft. Walton Beach, levels of contamination at sites in the Gulf of Mexico and in the southeastern United States were relatively low.

Not Available

1988-11-01

133

Biological and chemical detection of fumonisins produced on agar medium by Fusarium verticillioides isolates collected from corn in Sohag, Egypt.  

PubMed

Fusarium verticillioides (Sacc.) Nirenberg is among the most common Fusarium species corn pathogens worldwide, and has been recognized as a fumonisin B1 (FB1) and fumonisin B2 (FB2) producer. In the present work, extracts of 58 F. verticillioides isolates from corn samples collected from Sohag Governorate, Egypt, were tested for their biotoxicity and production of fumonisin toxins. Forty-four Fusarium verticillioides isolates out of 58 tested produced FB1 or FB1 and FB2 (15 and 29 isolates, respectively) on potato-sucrose agar medium, detected by TLC, whereas the other 14 isolates did not produce fumonisin toxins. HPLC crude extract analysis confirmed the results from TLC plates. Brine shrimp larvae as well as the Gram-negative bacteria Pseudomonas aeuroginosa showed low bio-sensitivity towards the F. verticillioides crude extract toxicity, whereas the Gram-positive bacteria Bacillus cereus and Bacillus subtilis, especially B. subtilis, showed higher sensitivity towards the tested Fusarium crude extracts. These results enabled us to bio-evaluate and chemically detect fumonisin mycotoxins using a simple agar medium technique. PMID:23760819

Aboul-Nasr, M B; Obied-Allah, M R A

2013-08-01

134

Equilibrium, photophysical, photochemical, and quantum chemical examination of anionic mercury(II) mono- and bisporphyrins.  

PubMed

Mercury(II) ion and 5,10,15,20-tetrakis(parasulfonato-phenyl)porphyrin anion can form 1:1, 2:2, and 3:2 (metal ion/porphyrin) out-of-plane (OOP) complexes, from which Hg2P2(8-) has not been identified until now. Identification of this species significantly promoted the confirmation of the composition and the precise elucidation of the equilibrium of Hg3P2(6-). Since the formation of each complex is too fast, their kinetic behavior was studied from the side of dissociation. The rate-determining step in dissociations, as well as in the formation of the 2:2 complex, that is, the dimerization of 1:1 complex, proved to be virtually first-order under these conditions, while the consecutive formations of HgP(4-) and Hg3P2(6-) are second-order reactions. The equilibria can be spectrophotometrically investigated because the Soret- as well as the Q-absorption bands of the free-base ligand are more and more red-shifted in the series of 1:1, 2:2, and 3:2 complexes, and the split of Q-bands disappears as the singlet-1 excited states become degenerate; in the case of bisporphyrins, the bands broaden, especially in the longer-wavelength region of the spectra. The quantum yield and the lifetime of S1-fluorescence from the macrocycle is decreased by the insertion of a mercury(II) ion due to distortion, and in bisporphyrins the luminescence totally ceases because their more complicated structure promotes other ways of energy dissipation. The lifetime of the triplet excited-state is also reduced by metalation. The transient absorption measured upon excitation of Hg3P2(6-) probably originates from Hg2P2(8-) formed by efficient photodissocation during the laser pulse. This photoinduced dissociation is characteristic to out-of-plane complexes, but in metallo-monoporphyrins it needs the energetically higher Soret-excitation; in bisporphyrins, it can take place during irradiation at the longer Q-wavelengths. Investigation of the intramolecular photoredox reactions has proved that for the increased efficiency of the indirect photoinduced LMCT, not the redox potential, but the position of the metal center is responsible. The two orders of magnitude higher photoredux quantum yield for the 3:2 complex, compared to that of the 2:2 species, can be explained by the repulsive effect of the inner mercury(II) ion pushing the other two farther out of the ligand cavity. In bisporphyrins the second excited states are photochemically more reactive than the first ones, while most of the photochemical processes of HgP(4-) originate from the first excited state. According to our quantum chemical calculations, the mercury(II) ion causes the expansion of the porphyrin-cavity; therefore its out-of-plane position is smaller than the value expected based on its ionic radius. In the hitherto unknown 2:2 dimer two 1:1 saucer-shaped monomers are kept together by secondary forces, mostly by pi-pi interaction, but their relative arrangement was not unequivocally determined by the two DFT functionals used. The arrangements with a symmetry axis or plane perpendicular to both rings are not favored; instead, the two monomers are shifted along the porphyrin planes, either in a Hg-P-Hg-P or a Hg-P-P-Hg order. Our time-dependent density functional theory (TD-DFT) calculations indicate that the electronic spectra are not very sensitive to the structure of the dimer, even though the environment of the porphyrin rings is quite different if one of the metal ions is between or outside of both macrocycles. The calculated spectral shifts agree only partially with the experimental data. The TD-DFT calculations suggest that the chromophores are not fully independent in the bisporphyrins and that the observed spectral shift cannot be uniquely assigned to the geometrical distortion of the porphyrin macrocyle. PMID:18954102

Valicsek, Zsolt; Lendvay, György; Horváth, Ottó

2008-11-20

135

Kinetic studies of Cd (II) and Pb (II) ions biosorption from aqueous media using untreated and chemically treated biosorbents.  

PubMed

Untreated and chemically treated Albizia coriaria, Erythrina abyssinica and Musa spp. were studied in batch for uptake of Cd(2+) and Pb(2+) ions at pH 2.0-9.0 and agitation time of 30-390 min. Optimum biosorption conditions were pH 4 for Pb(2+) ions and pH 5 for Cd(2+) ions, contact time was 3.5 hours at 24 ± 1 °C for 10 mg/L biosorbent dosage and initial metal ions concentration of 20 mg/L. Chemical treatment had a 10-17% biosorption efficiency enhancement for Cd(2+) ions and a 1.6-2.3% reduction effect for Pb(2+) ions. The sorption capacities for Cd(2+) and Pb(2+) ions for treated biosorbents were 1.760-1.738 mg g(-1) compared to 1.415-1.539 mg g(-1) for untreated materials. The pseudo second-order model suitably fitted the Cd(2+) and Pb(2+) ions biosorption data with regression coefficients (R(2)) of 0.9784-0.9999. Fitting of the Ho model to the experimental data showed that the biosorption mechanism for both metal ions studied was mainly a chemisorption process. Therefore, treated A. coriaria, E. abyssinica and Musa spp. were potential biosorbents for remediation of Cd(2+) ions and the untreated materials suitable for removing Pb(2+) ions from contaminated aqueous media. PMID:24901616

Bakyayita, G K; Norrström, A C; Nalubega, M; Kulabako, R N

2014-01-01

136

A Study of Diffusive Gradients in Thin Films for the Chemical Speciation of Zn(II), Cd(II), Pb(II), and Cu(II): The Role of Kinetics  

Microsoft Academic Search

The lability and mobility of Zn(II)–, Cd(II)–, Pb(II)–, and Cu(II)–humic acid complexes were studied using diffusive gradients\\u000a in thin films (DGT). A unique feature of this research was (1) the use of DGTs with diffusive layer thicknesses ranging from\\u000a 0.4 to 2.0 mm to study lability and mobility of Zn(II)–, Cd(II)–, Pb(II)–, and Cu(II)–humic acid complexes, combined with\\u000a (2) the application

Ibraheem Gaabass; John D. Murimboh; Nouri M. Hassan

2009-01-01

137

Thymine vanadyl(II) compound as a diabetic drug model: Chemical spectroscopic and antimicrobial assessments  

NASA Astrophysics Data System (ADS)

The aim of this study was to synthesize a novel bifunctionalized thymine vanadyl(II) compound. The solid vanadyl(II) compound has been characterized by elemental analyses (CHN), Raman laser, infrared spectra, molar conductivity, electronic spectra, thermogravimetric analyses (TGA), scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) studies. Electronic and magnetic measurements have confirmed that the speculated geometry of vanadyl(II) compound is square pyramidal geometry. The microbial test was performed for the vanadyl complex against some kinds of bacteria and fungi. The results suggested that [VO(Thy)2] adduct has an anti-diabetic profile.

El-Sayed, Mohamed Y.; Refat, Moamen S.

2014-09-01

138

Thymine vanadyl(II) compound as a diabetic drug model: chemical spectroscopic and antimicrobial assessments.  

PubMed

The aim of this study was to synthesize a novel bifunctionalized thymine vanadyl(II) compound. The solid vanadyl(II) compound has been characterized by elemental analyses (CHN), Raman laser, infrared spectra, molar conductivity, electronic spectra, thermogravimetric analyses (TGA), scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) studies. Electronic and magnetic measurements have confirmed that the speculated geometry of vanadyl(II) compound is square pyramidal geometry. The microbial test was performed for the vanadyl complex against some kinds of bacteria and fungi. The results suggested that [VO(Thy)2] adduct has an anti-diabetic profile. PMID:24785088

El-Sayed, Mohamed Y; Refat, Moamen S

2014-09-15

139

Organic, inorganic and total mercury determination in fish by chemical vapor generation with collection on a gold gauze and electrothermal atomic absorption spectrometry  

Microsoft Academic Search

A method for organic, inorganic and total mercury determination in fish tissue has been developed using chemical vapor generation and collection of mercury vapor on a gold gauze inside a graphite tube and further atomization by electrothermal atomic absorption spectrometry. After drying and cryogenic grinding, potassium bromide and hydrochloric acid solution (1 mol L?1 KBr in 6 mol L?1 HCl) was added

Fábio Andrei Duarte; Cezar Augusto Bizzi; Fabiane Goldschmidt Antes; Valderi Luiz Dressler; Érico Marlon de Moraes Flores

2009-01-01

140

Chemical fractionations in meteorites---II. Abundance patterns and their interpretation  

Microsoft Academic Search

Abundances of thirty-one volatile elements in meteorites are reviewed. In carbonaceous chondrites of Types I, II, and III and enstatite chondrites of Type I, abundances decrease by constant factors, in ratios of 1\\/0·6\\/0·3\\/0·7. In ordinary chondrites and Type II enstatite chondrites, nine elements (Au, Cu, F, Ga, Ge, S, Sb, Se and Sn) likewise are depleted by constant factors of

John W. Larimer; Edward Anders

1967-01-01

141

The Origin of MN II Emission in the Spectra of Chemically Peculiar Stars  

NASA Astrophysics Data System (ADS)

Emission from Mn II multiplet 13 (??6122-6132) in the spectrum of the 3He star 3 Centauri A and the hot, mild, HgMn star 46 Aquilae can be naturally explained by interlocked non-LTE effects. However, reproduction of the strength of the Mn II emission in both stars requires vertical stratification of the manganese abundance, with manganese concentrated high in the photosphere (column mass <~10-2 g cm-2). If this formation picture is correct, several additional transitions of Mn II with ?>8000 Å should also be present in emission in the spectrum of 3 Cen A. The wide range in the strength of Mn II multiplet 13 among upper main-sequence stars (ranging from absorption to emission) is made possible by the interplay in the non-LTE radiative transfer solution of the stellar Teff, manganese abundance, and manganese stratification profile. In particular, emission is strongly suppressed by a large manganese overabundance in the photosphere. This explains why the hot, mild, HgMn star 46 Aql, which has only a modest manganese enhancement, is detected in emission in Mn II multiplet 13 while other HgMn stars of similar Teff but with large photospheric manganese overabundances, such as ? Cancri, present Mn II multiplet 13 in absorption.

Sigut, T. A. A.

2001-01-01

142

PHYSICAL-CHEMICAL TREATMENT OF A MUNICIPAL WASTEWATER USING POWDERED CARBON. NO. II  

EPA Science Inventory

Salt Lake City municipal wastewater was treated in a nominal 100 gpm pilot plant by chemical coagulation-precipitation, powdered activated carbon adsorption and granular media filtration. Chemical-primary sludge was gravity thickened and vacuum filter dewatered. Spent carbon was ...

143

ANALYTICAL METHODS FOR A NATIONAL STUDY OF CHEMICAL RESIDUES IN FISH - II. PESTICIDES AND POLYCHLORINATED BIPHENYLS  

EPA Science Inventory

Analytical methods and a quality assurance plan have been developed to determine the concentration of a select group of bioaccumulatable chemicals in fish tissue. he analytes include PCBs and 21 pesticides and industrial chemicals. he methodology has been used to conduct a survey...

144

Optical detection/collection of toxic Cd(II) ions using cubic Ia3d aluminosilica mesocage sensors.  

PubMed

Optical sensors for selective removal and detection of extremely toxic ions such as cadmium (Cd(II)) in aquatic samples were successfully fabricated via simple strategy. Aluminosilica-based network platforms are used as selective mesopore shape and size carriers in order to fabricate optical sensors through the direct functionalization of ?, ?, ?, and ?-tetrakis(1-methylpyridinium-4-yl)porphine ?-toluenesulfonate (TMPyP) moieties without any prior surface modification using silane or thiol agents. In turn, the key advantage of a heretical three-dimensional (3D) cubic Ia3d mesocage is the facile access of target ions such as ion transports and the high affinity responses of TMPyP receptor-Cd(II) analyte binding events, which result in the easy generation and transduction of optical signals even at the trace level of the Cd(II) ion. The optical sensor design-based aluminosilica cages enable the sensitive detection and selective removal of Cd(II) ions even at ultra-trace concentrations of 10(-10)mol/dm(3) with rapid response time (in minutes). This rational strategy is crucial to the development of optical mesocollectors (i.e., probe surface-mounted naked-eye ion-sensor strips) with highly selective Cd(II) ion removal from aqueous water. These new classes of optical mesocollectors exhibit long-term stability and reusability of deleterious Cd(II) ions, which makes them efficient for various analytical applications. PMID:22939130

El-Safty, Sherif A; Shenashen, Mohamed A; Khairy, Mohamed

2012-08-30

145

PWR Steam Generator Chemical Cleaning. Phase I: Solvent and Process Development. Volume II.  

National Technical Information Service (NTIS)

A program to demonstrate chemical cleaning methods for removing magnetite corrosion products from the annuli between steam generator tubes and the tube support plates in vertical U-tube steam generators is described. These corrosion products have caused s...

A. P. Larrick R. A. Paasch T. M. Hall D. Schneidmiller

1979-01-01

146

PWR Steam Generator Chemical Cleaning. Phase I Final Report. Volume II.  

National Technical Information Service (NTIS)

Consolidated Edison Company of New York has organized and is managing a program for the Department of Energy to develop and demonstrate chemical cleaning methods for removing magnetite corrosion products from the annuli between steam generator tubes and t...

A. P. Larrick R. A. Paasch T. M. Hall D. Schneidmiller

1978-01-01

147

STRUCTURE-TOXICITY RELATIONSHIPS FOR INDUSTRIAL CHEMICALS CAUSING TYPE(II) NARCOSIS SYNDROME  

EPA Science Inventory

Several structure-activity relationships have been published for estimating the lethality of nonpolar nonelectrolytes to fish. The vast majority of non-reactive industrial chemicals produce toxicity symptoms consistent with narcosis. However, researchers have found that many chem...

148

CHEMICAL INTERACTIONS OF ARSENATE, ARSENITE, PHOSPHATE, AND SILICATE WITH IRON (II, III) HYDROXYCARBONATE GREEN RUST  

EPA Science Inventory

Granular zerovalent iron has been proposed to be used as a medium in permeable reactive barriers (PRBs) to remove arsenic from contaminated groundwater. Iron(II, III) hydroxycarbonate green rust (carbonate green rust, or CGR) is a major corrosion product of zerovalent iron under ...

149

CHEMICAL INTERACTIONS OF ARSENATE, ARSENITE, PHOSPHATE, AND SILICATE WITH IRON (II,III) HYDROXYCARBONATE GREEN RUST  

EPA Science Inventory

Granular zerovalent iron has been proposed to be used as a medium in permeable reactive barriers (PRBs) to remove arsenic from contaminated groundwater. Iron(II, III) hydroxycarbonate green rust (carbonate green rust, or CGR) is a major corrosion product of zerovalent iron under ...

150

Copper(II) removal from aqueous solutions by adsorption on non-treated and chemically modified cactus fibres.  

PubMed

The adsorption efficiency of a biomass by-product (cactus fibres) regarding the removal of copper(II) from aqueous solutions has been investigated before and after its chemical treatment. The chemical treatment of the biomass by-product included phosphorylation and MnO2-coating. The separation/removal efficiency has been studied as a function of pH, Cu(II) concentration, ionic strength, temperature and contact time. Evaluation of the experimental data shows that the MnO2-coated product presents the highest adsorption capacity, followed by the non-treated and phosphorylated material. Regarding the effect of ionic strength/salinity on the adsorption, in contrast to the removal efficiency of the phosphorylated product, which is significantly affected, the MnO2-coated and non-treated material don't show any effect, indicating the formation of inner-sphere surface complexes. The adsorption reaction is in all cases endothermic and relatively fast, particularly the adsorption on the MnO2-coated product. The results of the present study indicate that for the removal of bivalent metal-ions from contaminated waters the MnO2-coated material is expected to be the most effective adsorbent and an alternative to MnO2 resins for the treatment of environmentally relevant waters. PMID:24334902

Prodromou, M; Pashalidis, I

2013-01-01

151

The chemical history of molecules in circumstellar disks. II. Gas-phase species  

NASA Astrophysics Data System (ADS)

Context. The chemical composition of a molecular cloud changes dramatically as it collapses to form a low-mass protostar and circumstellar disk. Two-dimensional (2D) chemodynamical models are required to properly study this process. Aims: The goal of this work is to follow, for the first time, the chemical evolution in two dimensions all the way from a pre-stellar core into a circumstellar disk. Of special interest is the question whether the chemical composition of the disk is a result of chemical processing during the collapse phase, or whether it is determined by in situ processing after the disk has formed. Methods: Our model combines a semi-analytical method to get 2D axisymmetric density and velocity structures with detailed radiative transfer calculations to get temperature profiles and UV fluxes. Material is followed in from the core to the disk and a full gas-phase chemistry network - including freeze-out onto and evaporation from cold dust grains - is evolved along these trajectories. The abundances thus obtained are compared to the results from a static disk model and to observations of comets. Results: The chemistry during the collapse phase is dominated by a few key processes, such as the evaporation of CO or the photodissociation of H2O. Depending on the physical conditions encountered along specific trajectories, some of these processes are absent. At the end of the collapse phase, the disk can be divided into zones with different chemical histories. The disk is not in chemical equilibrium at the end of the collapse, so care must be taken when choosing the initial abundances for stand-alone disk chemistry models. Our model results imply that comets must be formed from material with different chemical histories: some of it is strongly processed, some of it remains pristine. Variations between individual comets are possible if they formed at different positions or different times in the solar nebula.

Visser, R.; Doty, S. D.; van Dishoeck, E. F.

2011-10-01

152

Chemical and isotopic data collected from groundwater, surface-water, and atmospheric precipitation sites in Upper Kittitas County, Washington, 2010-12  

USGS Publications Warehouse

As part of a multidisciplinary U.S. Geological Survey study of water resources in Upper Kittitas County, Washington, chemical and isotopic data were collected from groundwater, surface-water, and atmospheric precipitation sites from 2010 to 2012. These data are documented here so that interested parties can quickly and easily find those chemical and isotopic data related to this study. The locations of the samples are shown on an interactive map of the study area. This report is dynamic; additional data will be added to it as they become available.

Hinkle, Stephen R.; Ely, D. Matthew

2013-01-01

153

Liquid chromatography electrospray tandem mass spectrometric and desorption electrospray ionization tandem mass spectrometric analysis of chemical warfare agents in office media typically collected during a forensic investigation.  

PubMed

Most prior analytical studies have dealt with the determination of chemical warfare agents in environmental or biological matrices that would typically be collected following battlefield use or in support of the Chemical Weapons Convention. These methods may be useful for some investigations, but may not be practical for indoor forensic investigations where chemical warfare agent use is suspected. There is a need for analytical methods for chemical warfare agent identification in office media, including flooring, wall surfaces, office fabrics and paper products, which would typically be collected in an office environment during forensic investigations. During this study, typical office environment media were spiked at the 4-20microg/g level with either a complex munitions grade sample of tabun (GA) or with a standard containing the three nerve agents, sarin (GB), cyclohexyl methylphosphonofluoridate (GF), soman (GD) and the nerve agent simulant, triethyl phosphate (TEP), to evaluate the potentials of liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) and liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for forensic purposes. An emerging technique, desorption electrospray ionization (DESI-MS/MS), was also investigated for the direct determination of TEP, GB and GD sampled onto solid phase microextraction (SPME) fibers exposed to spiked office media. The spiked chemical warfare agents were recovered with varying efficiencies during this study, but in all cases sufficient chemical warfare agent was recovered for mass spectrometric identification purposes. Full high resolution mass spectra were acquired for all the chemical warfare agents in the continuum mode, which typically resulted in mass measurement errors of 0.001Da or less. PMID:16480731

D'Agostino, P A; Hancock, J R; Chenier, C L; Lepage, C R Jackson

2006-03-31

154

Note on the stochastic theory of a self-catalytic chemical reaction. II  

NASA Astrophysics Data System (ADS)

The general results of article I on the stochastic representation of the macroscopic stationary state of a self-catalytic chemical system are applied to a step-by-step chemical reaction. The relaxation times to the quasi-stationary state and to the final stationary state are computed by evaluating the first two non-trivial eigenvalues of the transition matrix. The previous results of Oppenheim, Shuler and Weiss are confirmed, precised and extended. The critical and subcritical cases are treated by the same method.

Dambrine, S.; Moreau, M.

1981-04-01

155

Chemical modification of Class II G-protein coupled receptor ligands  

PubMed Central

Recent research and clinical data have begun to demonstrate the huge potential therapeutic importance of ligands that modulate the activity of the secretin-like, Class II, G-protein coupled receptors (GPCRs). Ligands that can modulate the activity of these Class II GPCRs may have important clinical roles in the treatment of a wide variety of conditions such as osteoporosis, diabetes, amyotrophic lateral sclerosis and autism spectrum disorders. While these receptors present important new therapeutic targets, the large glycoprotein nature of their cognate ligands poses many problems with respect to therapeutic peptidergic drug design. These native peptides often exhibit poor bioavailability, metabolic instability, poor receptor selectivity and resultant low potencies in vivo. Recently, increased attention has been paid to the structural modification of these peptides to enhance their therapeutic efficacy. Successful modification strategies have included D-amino acid substitutions, selective truncation, and fatty acid acylation of the peptide. Through these and other processes, these novel peptide ligand analogs can demonstrate enhanced receptor subtype selectivity, directed signal transduction pathway activation, resistance to proteolytic degradation, and improved systemic bioavailability. In the future, it is likely, through additional modification strategies such as addition of circulation-stabilizing transferrin moieties, that the therapeutic pharmacopeia of drugs targeted towards Class II secretin-like receptors may rival that of the Class I rhodopsin-like receptors that currently provide the majority of clinically used GPCR-based therapeutics. Currently, Class II-based drugs include synthesized analogues of vasoactive intestinal peptide for type 2 diabetes or parathyroid hormone for osteoporosis.

Chapter, Megan C.; White, Caitlin M.; De Ridder, Angela; Chadwick, Wayne; Martin, Bronwen; Maudsley, Stuart

2009-01-01

156

Chemical chaperones improve transport and enhance stability of mutant ?-glucosidases in glycogen storage disease type II  

Microsoft Academic Search

Glycogen storage disease type II (GSDII; Pompe disease or acid maltase deficiency) is an autosomal recessive disorder caused by lysosomal acid ?-glucosidase (A?Glu) deficiency and manifests predominantly as skeletal muscle weakness. Defects in post-translational modification and transport of mutant A?Glu species are frequently encountered and may potentially be corrected with chaperone-mediated therapy. In the present study, we have tested this

Toshika Okumiya; Marian A. Kroos; Laura Van Vliet; Hiroaki Takeuchi; Ans T. Van der Ploeg; Arnold J. J. Reuser

2007-01-01

157

The GLAS editing procedures for the FGGE level II-B data collected during SOP-1 and 2  

NASA Technical Reports Server (NTRS)

The modifications made to the FGGE Level II-b data are discussed and the FORTRAN program developed to perform the modifications is described. It is suggested that the edited database is the most accurate one available for FGGE SOP-1 and 2.

Baker, W.; Edelmann, D.; Carus, H.

1981-01-01

158

Solvation forces in simple dense fluids. II. Effect of chemical potential  

SciTech Connect

The grand canonical ensemble Monte Carlo method is used to calculate the distribution of liquid molecules and the solvation force between two parallel solid surfaces separated by a simple liquid. Neither this distribution nor the solvation force are very sensitive to changes in the chemical potential (i.e., bulk density) of the interstitial liquid.

van Megen, W.J.; Snook, I.K.

1981-01-15

159

Robust Numerical Simulation of Porosity Evolution in Chemical Vapor Infiltration II. Two-Dimensional Anisotropic Fronts  

Microsoft Academic Search

A mathematical model is developed to study formation and evolution of pores during the chemical vapor infiltration (CVI) process. In this model the evolving fiber-gas interface is described by a level-set function with growth rate determined by the vapor precursor concentration and the local geometry. The vapor precursor, solely driven by diffusion, is described by a boundary value problem of

Shi Jin; Xuelei Wang

2001-01-01

160

A Chemical Kinetics Model to Predict Diesel Engine Performance. Part II. Bench-Test Procedures  

Microsoft Academic Search

Bench tests have been used to screen lubricants and additives for industrial fluids in machinery applications for a long time. As the cost of engine testing increases dramatically, the need for simple laboratory bench tests increases. Bench tests simulate a particular aspect of the engine operation such as oxidation or wear, but the engine operation blends both mechanical, chemical, and

Stephen M. Hsu; Chun-I Chen

2003-01-01

161

Chemical Species of Iodine in Some Seaweeds II. Iodine-Bound Biological Macromolecules  

Microsoft Academic Search

The distribution of iodine in various biological macromolecules in Sargassum kjellmanianum was studied using neutron activation analysis combined with chemical and biochemical separation techniques. The results indicate that iodine is mainly bound with protein, part of iodine with pigment and polyphenol, and little with polysaccharides, such as algin, fucoidan and cellulose. This result is significant for the mechanism of enriching

Xiaolin Hou; Xiaojun Yan; Chifang Chai

2000-01-01

162

PWR steam generator chemical cleaning. Phase I: solvent and process development. Volume II  

Microsoft Academic Search

A program to demonstrate chemical cleaning methods for removing magnetite corrosion products from the annuli between steam generator tubes and the tube support plates in vertical U-tube steam generators is described. These corrosion products have caused steam generator tube ''denting'' and in some cases have caused tube failures and support plate cracking in several PWR generating plants. Laboratory studies were

A. P. Larrick; R. A. Paasch; T. M. Hall; D. Schneidmiller

1979-01-01

163

Chemical composition and swelling of normal and osteoarthrotic femoral head cartilage. II. Swelling  

Microsoft Academic Search

Studies of the equilibrium, partition, and diffusion of tritiated water were carried out on normal and osteoarthrotic cartilage as well as on cartilage from which proteoglycans had been extracted chemically. All the water was found to be freely exchangeable in both normal and degenerate specimens. The diffusiviity of the water was equal to about 40% of the value in free

A Maroudas; M Venn

1977-01-01

164

Physical and Chemical Data from Eolian Sediment Collected along a Transect from the Mojave Desert to the Colorado Plateau.  

National Technical Information Service (NTIS)

This report presents data and describes the methodology for magnetic, geochemical, and textural measurements of sediment and bedrock samples collected along a transect across the Southwestern United States. The results presented here support a study that ...

H. L. Goldstein J. C. Yount M. C. Reheis P. J. Lamothe R. L. Reynolds

2007-01-01

165

Studies on the chemical modification of the tyrosine residue in bovine neurophysin-II  

PubMed Central

1. Bovine neurophysin-II contains 1mol of tyrosine residue/10000g of protein. This residue could be readily nitrated with tetranitromethane. On hydrolysis and amino acid analysis 1mol of 3-nitrotyrosine was found/10000g of protein. Starchgel electrophoresis at pH8.5 showed that nitration had converted the native protein into a single, more acidic species. The increase in acidity was consistent with the observed fall in pK of the tyrosine hydroxyl from 9.2 in native neurophysin to 7.3 in the nitrated protein. Further, the absence of any intermediate species, even under conditions of minimum substitution, confirmed that the molecular weight of the monomer is 10000. 2. O-Acetylation of the tyrosine residue was carried out with N-acetylimidazole, in conjunction with the reversible blocking of amino groups by citraconylation. The degree of O-acetylation, determined spectroscopically, was 0.9mol of O-acetyltyrosine/10000g of protein. 3. The hormone-binding ability of modified protein was tested by equilibrium dialysis and was found to be unchanged by either nitration or O-acetylation of the tyrosine residue. 4. Interaction of neurophysin-II and [8-arginine]-vasopressin gave rise to a characteristic difference spectrum with a peak at 286.8nm and shoulder at 279.6nm. Part of this hyperchromicity is thought to result from entry of the tyrosine residue at position 2 in the hormone into the hydrophobic environment of the binding site. With nitrated neurophysin-II a second peak appeared at 436nm, showing that the tyrosine of the protein is also perturbed. The very large red shift (84nm) in this region suggests that the 3-nitrotyrosyl residue not only enters a more hydrophobic environment on protein–hormone interaction, but is caused to ionize more fully by the approach of some positively charged group.

Furth, Anna J.; Hope, D. B.

1970-01-01

166

Chemicals and Energy from Medical Polymer Wastes II. Maleated Pyrolysis Products in IPP\\/LLDPE Processing  

Microsoft Academic Search

A way for high valorisation of the waxy product resulted from the pyrolysis of disposable syringes it has been proposed. The waxy product has been chemically modified with maleic anhydride and then has been tested in the processing of IPP\\/ LLDPE blends on a Haake-Buchler rheometer or on a Werner and Pfeiderer ZSM-30 corotating twin screw extruder.The compatibility of components

Cornelia Vasile; Rudolph D. Deanin; Mihaela Mihaies; Christian Roy; Abdelkader Chaala; Wenguang Ma

1997-01-01

167

Chemical priming for spinal cord injury: a review of the literature part II—potential therapeutics  

Microsoft Academic Search

Introduction  Spinal cord injury is a complex cascade of reactions secondary to the initial mechanical trauma that puts into action the\\u000a innate properties of the injured cells, the circulatory, inflammatory, and chemical status around them, into a non-permissive\\u000a and destructive environment for neuronal function and regeneration. Priming means putting a cell, in a state of “arousal”\\u000a towards better function. Priming can

Martin M. Mortazavi; Ketan Verma; Aman Deep; Fatemeh B. Esfahani; Patrick R. Pritchard; R. Shane Tubbs; Nicholas Theodore

2011-01-01

168

Historical estimates of external gamma exposure and collective external gamma exposure from testing at the Nevada Test Site. II. Test series after Hardtack II, 1958, and summary.  

PubMed

The historical data on the cumulative individual external gamma exposures are tabulated for communities around the Nevada Test Site for the time periods of 1961 to the signing of the Limited Test Ban Treaty on 5 August 1963, and from then until 1975. The collective exposures during the two time periods are calculated to be 610 and 320 person-R, respectively. The total collective external gamma exposure from 1951 through 1975 for these communities s calculated to be 86,000 person-R. The area considered includes the countries of Clark, Lincoln, Nye, and White Pine in Nevada and the countries of Iron and Washington in Utah; inclusion of Salt Lake City would have substantially increased the calculated collective exposure because of the large population. The methods of calculation are reviewed. Also, the historical data on the assessment of dose via ingestion are reviewed with emphasis on the dose to the thyroid of infants living in St. George, UT, at the time of fallout from event HARRY on 19 May 1953. PMID:2211112

Anspaugh, L R; Ricker, Y E; Black, S C; Grossman, R F; Wheeler, D L; Church, B W; Quinn, V E

1990-11-01

169

Historical estimates of external gamma exposure and collective external gamma exposure from testing at the Nevada Test Site. II. Test series after Hardtack II, 1958, and summary  

SciTech Connect

The historical data on the cumulative individual external gamma exposures are tabulated for communities around the Nevada Test Site for the time periods of 1961 to the signing of the Limited Test Ban Treaty on 5 August 1963, and from then until 1975. The collective exposures during the two time periods are calculated to be 610 and 320 person-R, respectively. The total collective external gamma exposure from 1951 through 1975 for these communities s calculated to be 86,000 person-R. The area considered includes the countries of Clark, Lincoln, Nye, and White Pine in Nevada and the countries of Iron and Washington in Utah; inclusion of Salt Lake City would have substantially increased the calculated collective exposure because of the large population. The methods of calculation are reviewed. Also, the historical data on the assessment of dose via ingestion are reviewed with emphasis on the dose to the thyroid of infants living in St. George, UT, at the time of fallout from event HARRY on 19 May 1953.

Anspaugh, L.R.; Ricker, Y.E.; Black, S.C.; Grossman, R.F.; Wheeler, D.L.; Church, B.W.; Quinn, V.E. (Lawrence Livermore National Laboratory, CA (USA))

1990-11-01

170

Spatial distribution and temporal variation of chemical species in the bulk atmospheric aerosols collected at the Okinawa archipelago, Japan  

Microsoft Academic Search

The economic development and population growth in recent Asia have been increasing air pollution. A computer simulation study showed that air pollutants emitted from Asian continent could spread quickly within northern hemisphere. We initiated a study to elucidate the special distribution and chemical characterization of atmospheric aerosols around Okinawa archipelago, Japan. Okinawa Island is situated approximately 1500 km south of

D. Handa; Y. Somada; M. Ijyu; S. Azechi; F. Nakaema; T. Arakaki; A. Tanahara

2009-01-01

171

[Unusual late complication after esophagoplasty type Gavriliu II for esophageal stenosis from chemical burns--cancer of the esophagoplasty tube].  

PubMed

We present the case of a 56 year old female, who in 23 years after esophagoplasty type Gavriliu II, with pre-sternal tube for esophageal chemical burn stenosis, develops a cancer in the upper third of the gastric tube, with a fast evolution to malnutrition, through lumen obturation. The evolution post-esophagoplasty was marked by malfunction of the neo-esophagus, characterized through dysphagia and distal dilatation, requiring many abdominal and pre-sternal reinterventions. The objective of the present surgical intervention was to assure a way for enteral nutrition (gastrostomy for feeding) and to extirpate the gastro-esophagoplasty tube. It is discussed the characteristic feature of the case: the difficulty of the stage-evolutive integration of this malignant disease location, the etiopathogenic factors that contributed to the malignant evolution of the antral portion of the gastro-esophagoplasty tube, the limits of the surgical treatment. PMID:15957461

Pa?alega, M; Burdescu, C; Me?in?, C; Mirea, C; Tenea, T; Vasile, I

2005-01-01

172

Development of a transactivator in hepatoma cells that allows expression of phase I, phase II, and chemical defense genes.  

PubMed

Precise control of the level of protein expression in cells can yield quantitative and temporal information on the role of a given gene in normal cellular physiology and on exposure to chemicals and drugs. This is particularly relevant to liver cells, in which the expression of many proteins, such as phase I and phase II drug-metabolizing enzymes, vary widely between species, among individual humans, and on exposure to xenobiotics. The most widely used gene regulatory system has been the tet-on/off approach. Although a second-generation tet-on transactivator was recently described, it has not been widely investigated for its potential as a tool for regulating genes in cells and particularly in cells previously recalcitrant to the first-generation tet-on approach, such as hepatocyte-derived cells. Here we demonstrate the development of two human (HepG2 and HuH7) and one mouse (Hepa1c1c7) hepatoma-derived cell lines incorporating a second-generation doxycycline-inducible gene expression system and the application of the human lines to control the expression of different transgenes. The two human cell lines were tested for transient or stable inducibility of five transgenes relevant to liver biology, namely phase I (cytochrome P-450 2E1; CYP2E1) and phase II (glutathione S-transferase P1; GSTP1) drug metabolism, and three transcription factors that respond to chemical stress [nuclear factor erythroid 2 p45-related factors (NRF)1 and 2 and NFKB1 subunit of NF-kappaB]. High levels of functional expression were obtained in a time- and dose-dependent manner. Importantly, doxycycline did not cause obvious changes in the cellular proteome. In conclusion, we have generated hepatocyte-derived cell lines in which expression of genes is fully controllable. PMID:16135546

Goldring, Chris E P; Kitteringham, Neil R; Jenkins, Rosalind; Lovatt, Cerys A; Randle, Laura E; Abdullah, Azman; Owen, Andrew; Liu, Xiaoping; Butler, Philip J; Williams, Dominic P; Metcalfe, Peter; Berens, Christian; Hillen, Wolfgang; Foster, Brian; Simpson, Alec; McLellan, Lesley; Park, B Kevin

2006-01-01

173

Base Line Data Collection. Volume II. Section I. A Study of Crime in the Urban Setting: Omaha, Nebraska.  

National Technical Information Service (NTIS)

This report is a presentation of facts about serious crimes in Omaha, comparison of these facts, and isolation and identification of specific target areas and populations. It initiates a base line data program upon which future data collection may be base...

G. C. Dawson K. L. Johnson

1973-01-01

174

On the validity of 3D polymer gel dosimetry: II. physico-chemical effects.  

PubMed

This study quantifies some major physico-chemical factors that influence the validity of MRI (PAGAT) polymer gel dosimetry: temperature history (pre-, during and post-irradiation), oxygen exposure (post-irradiation) and volumetric effects (experiment with phantom in which a small test tube is inserted). Present results confirm the effects of thermal history prior to irradiation. By exposing a polymer gel sample to a linear temperature gradient of ?2.8 °C cm?¹ and following the dose deviation as a function of post-irradiation time new insights into temporal variations were added. A clear influence of the temperature treatment on the measured dose distribution is seen during the first hours post-irradiation (resulting in dose deviations up to 12%). This effect diminishes to 5% after 54 h post-irradiation. Imposing a temperature offset (maximum 6 °C for 3 h) during and following irradiation on a series of calibration phantoms results in only a small dose deviation of maximum 4%. Surprisingly, oxygen diffusing in a gel dosimeter up to 48 h post-irradiation was shown to have no effect. Volumetric effects were studied by comparing the dose distribution in a homogeneous phantom compared to the dose distribution in a phantom in which a small test tube was inserted. This study showed that the dose measured inside the test tube was closer to the ion chamber measurement in comparison to the reference phantom without test tube by almost 7%. It is demonstrated that physico-chemical effects are not the major causes for the dose discrepancies encountered in the reproducibility study discussed in the concurrent paper (Vandecasteele and De Deene 2013a Phys. Med. Biol. 58 19-42). However, it is concluded that these physico-chemical effects are important factors that should be addressed to further improve the dosimetric accuracy of 3D MRI polymer gel dosimetry. PMID:23221322

Vandecasteele, Jan; De Deene, Yves

2013-01-01

175

On the validity of 3D polymer gel dosimetry: II. Physico-chemical effects  

NASA Astrophysics Data System (ADS)

This study quantifies some major physico-chemical factors that influence the validity of MRI (PAGAT) polymer gel dosimetry: temperature history (pre-, during and post-irradiation), oxygen exposure (post-irradiation) and volumetric effects (experiment with phantom in which a small test tube is inserted). Present results confirm the effects of thermal history prior to irradiation. By exposing a polymer gel sample to a linear temperature gradient of ˜2.8 °C cm-1 and following the dose deviation as a function of post-irradiation time new insights into temporal variations were added. A clear influence of the temperature treatment on the measured dose distribution is seen during the first hours post-irradiation (resulting in dose deviations up to 12%). This effect diminishes to 5% after 54 h post-irradiation. Imposing a temperature offset (maximum 6 °C for 3 h) during and following irradiation on a series of calibration phantoms results in only a small dose deviation of maximum 4%. Surprisingly, oxygen diffusing in a gel dosimeter up to 48 h post-irradiation was shown to have no effect. Volumetric effects were studied by comparing the dose distribution in a homogeneous phantom compared to the dose distribution in a phantom in which a small test tube was inserted. This study showed that the dose measured inside the test tube was closer to the ion chamber measurement in comparison to the reference phantom without test tube by almost 7%. It is demonstrated that physico-chemical effects are not the major causes for the dose discrepancies encountered in the reproducibility study discussed in the concurrent paper (Vandecasteele and De Deene 2013a Phys. Med. Biol. 58 19-42). However, it is concluded that these physico-chemical effects are important factors that should be addressed to further improve the dosimetric accuracy of 3D MRI polymer gel dosimetry. Both authors contributed equally to this study.

Vandecasteele, Jan; De Deene, Yves

2013-01-01

176

Metal-poor Dwarf Galaxies in the SIGRID Galaxy Sample. I. H II Region Observations and Chemical Abundances  

NASA Astrophysics Data System (ADS)

In this paper we present the results of observations of 17 H II regions in thirteen galaxies from the SIGRID sample of isolated gas-rich irregular dwarf galaxies. The spectra of all but one of the galaxies exhibit the auroral [O III] 4363 Å line, from which we calculate the electron temperature, Te , and gas-phase oxygen abundance. Five of the objects are blue compact dwarf galaxies, of which four have not previously been analyzed spectroscopically. We include one unusual galaxy which exhibits no evidence of the [N II] ?? 6548,6584 Å lines, suggesting a particularly low metallicity (< Z ?/30). We compare the electron temperature based abundances with those derived using eight of the new strong-line diagnostics presented by Dopita et al. Using a method derived from first principles for calculating total oxygen abundance, we show that the discrepancy between the Te -based and strong-line gas-phase abundances have now been reduced to within ~0.07 dex. The chemical abundances are consistent with what is expected from the luminosity-metallicity relation. We derive estimates of the electron densities and find them to be between ~5 and ~100 cm–3. We find no evidence for a nitrogen plateau for objects in this sample with metallicities 0.5 > Z ? > 0.15.

Nicholls, David C.; Dopita, Michael A.; Sutherland, Ralph S.; Jerjen, Helmut; Kewley, Lisa J.; Basurah, Hassan

2014-05-01

177

Extremely metal-deficient red giants. II. Chemical abundances in 21 halo giants  

SciTech Connect

Using a model-atmosphere analysis, we have determined chemical abundances in 21 red giants of the galactic halo. Nine new field stars from Bond's recent objective-prism survey, along with the well-known halo giant HD 122563, were analyzed on new high-dispersion spectrograms obtained at Palomar, Mount Wilson, and Cerro Tololo. Five giants in the globular cluster M13, three in M3, and three additional field stars were also analyzed using previously published equivalent-widths, providing a total sample of 21 halo giants analyzed in a homogeneous manner.

Luck, R.E.; Bond, H.E.

1981-03-15

178

An industry wide mortality study of chemical workers occupationally exposed to benzene. II. Dose response analyses.  

PubMed Central

The data presented in this paper show statistically significant dose response relations between cumulative exposure to benzene (ppm-months) and mortality from both all lymphopoietic cancer combined and leukaemia. Chemical workers with a cumulative exposure to benzene of at least 720 ppm-months experienced a relative risk of 3.93 for lymphatic and haematopoietic cancer when compared with workers with no occupational exposure. The dose response relation between cumulative exposure and non-Hodgkin's lymphopoietic cancer was of borderline statistical significance (p = 0.06). No dose response relation was detected for any other causes of death.

Wong, O

1987-01-01

179

Chemical characterization of ambient aerosol collected during the northeast monsoon season over the Arabian Sea: Anions and cations  

Microsoft Academic Search

Ambient aerosol samples were collected over the Arabian Sea during the month of March 1997, aboard the German R\\/V Sonne, as part of the German JGOFS project (Joint Global Ocean Flux Study). This is the third study in a series of analogous measurements taken over the Arabian Sea during different seasons of the monsoon. Dichotomous high volume collector samples were

Anne M. Johansen; Michael R. Hoffmann

2004-01-01

180

Chemical characterization of ambient aerosol collected during the northeast monsoon season over the Arabian Sea: Anions and cations  

Microsoft Academic Search

(1) Ambient aerosol samples were collected over the Arabian Sea during the month of March 1997, aboard the German R\\/V Sonne, as part of the German JGOFS project (Joint Global Ocean Flux Study). This is the third study in a series of analogous measurements taken over the Arabian Sea during different seasons of the monsoon. Dichotomous high volume collector samples

Anne M. Johansen

2004-01-01

181

Divergent Chemical Cues Elicit Seed Collecting by Ants in an Obligate Multi-Species Mutualism in Lowland Amazonia  

Microsoft Academic Search

In lowland Amazonian rainforests, specific ants collect seeds of several plant species and cultivate them in arboreal carton nests, forming species-specific symbioses called ant-gardens (AGs). In this obligate mutualism, ants depend on the plants for nest stability and the plants depend on ant nests for substrate and nutrients. AG ants and plants are abundant, dominant members of lowland Amazonian ecosystems,

Elsa Youngsteadt; Patricia Guerra Bustios; Coby Schal; Walter S. Leal

2010-01-01

182

Organic Chemical Concentrations and Reproductive Biomarkers in Common Carp (Cyprinus carpio) Collected from Two Areas in Lake Mead, Nevada, May 1999-May 2000  

USGS Publications Warehouse

The U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, National Park Service, Bureau of Reclamation, and Nevada Department of Wildlife, collected and assessed data to determine the general health and reproductive status of common carp (Cyprinus carpio) at two study areas in Lake Mead, Nevada, during May 1999-May 2000. These data will form the basis of interpretations and provide a comparison for continuing studies on the health of the ecosystem in Lake Mead. One study area, Las Vegas Bay, is in the western part of Lake Mead. Las Vegas Bay receives inflows from Las Vegas Wash, which is predominantly tertiary-treated wastewater effluent, and to a lesser extent stormwater runoff from Las Vegas, Henderson, and other nearby communities, and from ground water underlying Las Vegas Valley. The other study area, Overton Arm, is in the northern extent of Lake Mead. Overton Arm receives inflow from the Virgin and Muddy Rivers, which historically are not influenced by wastewater effluent. Both sexes of common carp were collected bimonthly for 12 months using boat-mounted electrofishing gear (a direct electric current is used to temporarily immobilize fish for capture) to determine their health and reproductive status and any relation between these factors and environmental contaminants. This report presents fish tissue chemistry, organic chemical compound concentrations, and biomarker data for 83 male common carp collected from Las Vegas Bay, similar organic chemistry results for 15 male common carp, and similar biomarker measures for 80 male common carp collected from Overton Arm. Tissue chemistry results also are presented for 16 female common carp and biomarker measures for 79 female common carp collected from Las Vegas Bay, and tissue chemistry results for 15 female common carp and biomarker measures for 81 female common carp collected from Overton Arm. Thirty-three organic chemical compounds plus total concentrations for four groups of compounds (chlordanes, polychlorinated biphenyls [PCBs], brominated diphenyl ethers [BDEs], and triclosans) were analyzed from extracts of whole-body tissue using gas chromatography/mass spectrometry in male common carp from Las Vegas Bay during May 1999 through May 2000. All 33 compounds were detected in at least one sample of whole-body tissue from male common carp collected in Las Vegas Bay. In Overton Arm, 37 organic compounds plus total concentrations of three groups of compounds (PCBs, BDEs, and triclosans) were analyzed in male common carp where 20 (54 percent) of the compounds were detected. Sixteen of the 33 compounds detected in male common carp from Las Vegas Bay and 10 compounds detected in males from Overton Arm have the potential to disrupt the endocrine system in fish in Lake Mead. During May and June 1999, the mean concentration of all organic compounds detected in male common carp was 670 micrograms per kilogram from Las Vegas Bay and 109 micrograms per kilogram from Overton Arm. Twenty-seven organic compounds plus total PCBs were analyzed from extracts of whole-body tissue in female common carp collected in Las Vegas Bay and Overton Arm during May 1999. Twenty-four (86 percent) of these compounds were detected in at least one sample of whole-body tissue from female common carp collected from Las Vegas Bay while 10 (36 percent) chemical compounds were detected in female common carp from Overton Arm during that same period. Median concentrations of all chemical compounds were higher in female common carp from Las Vegas Bay compared to those collected from Overton Arm except Dacthal (DCPA), which was similar between sites. Biomarker measures obtained for male and female common carp include gonadosomatic index (percentage of gonad weight to total body weight), plasma vitellogenin (a phospholipid protein normally produced by female common carp and other oviparous fish), and condition factor [body weight/(fork length)3]. Biomarker measures for male c

Goodbred, Steven L.; Leiker, Thomas J.; Pati?o, Reynaldo; Jenkins, Jill A.; Denslow, Nancy D.; Orsak, Erik; Rosen, Michael R.

2007-01-01

183

The 2011 October Draconids outburst - II. Meteoroid chemical abundances from fireball spectroscopy  

NASA Astrophysics Data System (ADS)

On 2011 October 8, the Earth crossed dust trails ejected from comet 21P/Giacobini-Zinner in the late 19th and early 20th Century. This gave rise to an outburst in the activity of the October Draconid meteor shower, and an international team was organized to analyse this event. The SPanish Meteor Network (SPMN) joined this initiative and recorded the October Draconids by means of low-light level CCD cameras. In addition, spectroscopic observations were carried out. Tens of multistation meteor trails were recorded, including an extraordinarily bright October Draconid fireball (absolute magnitude -10.5) that was simultaneously imaged from three SPMN meteor observing stations located in Andalusia. Its spectrum was obtained, showing a clear evolution in the relative intensity of emission lines as the fireball penetrated deeper into the atmosphere. Here, we focus on the analysis of this remarkable spectrum, but also discuss the atmospheric trajectory, atmospheric penetration and orbital data computed for this bolide which was probably released during 21P/Giacobini-Zinner return to perihelion in 1907. The spectrum is discussed together with the tensile strength for the October Draconid meteoroids. The chemical profile evolution of the main rocky elements for this extremely bright bolide is compared with the elemental abundances obtained for five October Draconid fireballs also recorded during our spectroscopic campaign but observed only at a single station. Significant chemical heterogeneity between the small meteoroids is found as we should expect for cometary aggregates being formed by diverse dust components.

Madiedo, José M.; Trigo-Rodríguez, Josep M.; Konovalova, Natalia; Williams, Iwan P.; Castro-Tirado, Alberto J.; Ortiz, José L.; Cabrera-Caño, Jesús

2013-07-01

184

Water-soluble lipoproteins from yolk granules in sea urchin eggs. II. Chemical composition.  

PubMed

The chemical composition of yolk lipoproteins (YLP-1, 2, and 3) was determined. YLP-1, 2, and 3 were quite similar as regards the chemical composition of lipids, proteins, and carbohydrate moieties. Each lipoprotein has an average dry weight composition of lipids (55--72%) and apo-lipoproteins (28--45%) containing protein, hexose, hexosamine, and sialic acid. In each lipoprotein, triacylglycerol is a major lipid component (70--83%), followed by phospholipid (8--16%), cholesterol (free and esterified, 8--10%), and free fatty acid (3--4%). Phosphatidylcholine and phosphatidylserine account for 68--74% and 16--24% of the phospholipids, respectively. The fatty acid compositions of total lipids from each lipoprotein are quite similar, with a high degree of unsaturation (63--65%). The carbohydrate content of apolipoprotiens from each lipoprotein is remarkably high (27--31% of apo-lipoproteins) and their composition is very simple: mannose and glucosamine are major constituents in the polysaccharide moiety of each lipoprotein and sialic acid is all in the N-glycolyl form. The amino acid compositions of apo-lipoproteins are quite similar in YLP-1, 2, and 3, with high contents of aspartic acid, glutamic acid, threonine, serine, and leucine. Furthermore, a small amount of glycolipids is present in the yolk lipoproteins. They were separated into six components on TLC. All of them are resorcinol-positive, indicating the presence of sialoglycolipids. PMID:457646

Deguchi, K; Kawashima, S; Ii, I; Ueta, N

1979-06-01

185

State-of-the-art of non-hormonal methods of contraception: II. Chemical barrier contraceptives.  

PubMed

Chemical contraceptives mainly known as spermicides are one of the oldest types of contraceptives. The industrial revolution facilitated new developments, and they became a leading and widespread method. However, their use declined in the second half of the 20th century, and came under focus again only with the upsurge of sexually transmitted infections (STIs). The effectiveness of spermicides depends on the users' compliance and pregnancy rates vary widely: from 6/100 woman-year (with perfect use) to 26/100 woman-year (with typical use). Preparations consist of two components: an excipient (foam, cream, jelly, soluble film, suppository or tablet); and a chemical agent with spermicidal properties (acidic compound, microbicidal agent, detergent). The most widely used active agent has been the surface active (detergent) nonoxynol-9 (N-9). Based on their mode of action (surfactant effect of detergents, enzymatic action of microbicides on cell metabolism) spermicides were thought to provide protection against STIs including HIV. Recent studies have, however, shown that detergents may actually increase the risk. Because of this, there is an urgent need for a suitable non-detergent spermicide, and research should focus on developing new compounds to replace N-9 and other agents having similar undesired effects. This paper reviews the latest studies reporting results on these recent developments. PMID:20055729

Batár, István

2010-04-01

186

[A comparative study on the chemical components of Salvia miltiorrhiza Bge. collected from Zhongjiang of Sichuan and from other habitats].  

PubMed

In this paper, the chemical components in the root of Salvia miltiorrhiza from three habitats (Zhongjiang of Sichuan, Henan and Shandong) were comparatively studied. The results show that the TLC chromatogram and contents of tanshinone IIA in the crude drugs are about the same, the sodium content appears to be lower in the sample from Sichuan, but the contents of other metallic elements are about the same in the samples from different habitats. PMID:11038938

Chen, X; Li, W; Xia, W; Luo, H; Liu, X

1997-09-01

187

Trace metal levels and some chemical parameters in herby cheese collected from south eastern Anatolia-Turkey  

Microsoft Academic Search

Due to the consumption of the herby cheese in south eastern Anatolia-Turkey is at high ratio, chemical parameters such as\\u000a dry matter, pH, acidity, aCl, protein, fat and trace metal contents in 50 different herby cheeses produced at this region\\u000a have been determined in the presented study. The content of lead, copper, cobalt, nickel, chromium, cadmium, and iron have\\u000a been

Aydin Vural; Ibrahim Narin; Mehmet Emin Erkan; Mustafa Soylak

2008-01-01

188

Studies in photochemical smog chemistry. I. Atmospheric chemistry of toluene. II. Analysis of chemical reaction mechanisms for photochemical smog  

SciTech Connect

This study focuses on two related topics in the gas phase organic chemistry of importance in urban air pollution. Part I describes an experimental and modeling effort aimed at developing a new explicit reaction mechanism for the atmospheric photooxidation of toluene. This mechanism is tested using experimental data from both indoor and outdoor smog chamber facilities. The predictions of the new reaction mechanism are found to be in good agreement with both sets of experimental data. Additional simulations performed with the new mechanism are used to investigate various mechanistic paths, and to gain insight into areas where the understanding is not complete. The outdoor experimental facility, which was built to provide the second set of experimental data, consists of a 65 cubic meter teflon smog chamber together with full instrumentation capable of measuring ozone, nitrogen dioxide, nitric oxide, peroxyacetyl nitrate (PAN), carbon monoxide, relative humidity, temperature, aerosol size distributions, and of course toluene and its photooxidation products. In Part II, a theoretical analysis of lumped chemical reaction mechanisms for photochemical smog is presented. Included is a description of a new counter species analysis technique which can be used to analyze any complex chemical reaction mechanism. Finally, a new lumped mechanism for photochemical smog is developed and tested against experimental data from two smog chamber facilities. Advantages of this mechanism relative to the existing lumped mechanisms are discussed.

Leone, J.A.

1985-01-01

189

Results of chemical and stable isotopic analyses of water samples collected in the Patagonia Mountains, southern Arizona  

USGS Publications Warehouse

Water samples were collected in the Patagonia Mountains in February, 1997. Most of the samples were collected from portals of abandoned mines, or from stream drainages immediately downstream from abandoned mines. Most of the samples have low pH ( 1000 mg/L). Anion composition of the water samples is dominated by sulfate, while cation compositions range from calcium-dominated to mixed calcium-magnesium or calcium-sodium-dominated waters. Metals such as iron, manganese, copper, zinc, and aluminum contribute a significant portion (>10%) of the cation content to the water samples. Because of the low pH?s, protons contribute up to several percent of the cation character of the waters in some of the samples. The data are presented in tabular and graphical formats, with descriptions of data quality and brief descriptions of results.

Wanty, Richard B.; Shanks, Wayne C., III; Lamothe, Paul; Meier, Al; Lichte, Fred; Briggs, Paul H.; Berger, Byron R.

2001-01-01

190

Bioactivity, Chemical Profiling, and 16S rRNA-Based Phylogeny of Pseudoalteromonas Strains Collected on a Global Research Cruise  

Microsoft Academic Search

One hundred one antibacterial Pseudoalteromonas strains that inhibited growth of a Vibrio anguillarum test strain were collected on a global research cruise (Galathea 3), and 51 of the strains repeatedly demonstrated antibacterial\\u000a activity. Here, we profile secondary metabolites of these strains to determine if particular compounds serve as strain or\\u000a species markers and to determine if the secondary metabolite profile

Nikolaj G. Vynne; Maria Månsson; Kristian F. Nielsen; Lone Gram

191

Acid base properties of cyanobacterial surfaces. II: Silica as a chemical stressor influencing cell surface reactivity  

NASA Astrophysics Data System (ADS)

Bacteria grow in complex solutions where the adsorption of aqueous species and nucleation of mineral phases on the cell surface may interfere with membrane-dependent homeostatic functions. While previous investigations have provided evidence that bacteria may alter their surface chemical properties in response to environmental stimuli, to our knowledge no effort has been made to evaluate surface compositional changes resulting from non-nutritional chemical stresses within a quantitative framework applicable to surface complexation modeling. We consider here the influence of exposure to silica on cyanobacterial surface chemistry, particularly in light of the propensity for cyanobacteria to become silicified in geothermal environments. Using data modeled from over 50 potentiometric titrations of the unsheathed cyanobacterium Anabaena sp. strain PCC 7120, we find that both abiotic geochemical and biotic biochemical-assimilatory factors have important and different effects on cell surface chemistry. Changes in functional group distribution that resulted from growth by different nitrogen assimilation pathways were greatest in the absence of dissolved silica and less important in its presence. Furthermore, out of the three nitrogen assimilation pathways investigated, in terms of surface functional group distribution, nitrate-reducing cultures were least sensitive, and ammonium-assimilating cultures were most sensitive, to changes in media silica concentration. When functional group distributions were plotted as a function of silica concentration, it appears that, with higher silica concentrations, basic groups (p Ka > 7) increase in concentration relative to acidic groups (p Ka < 7), and the total ligand densities (on a per-weight basis) decreased. The results imply a decrease in both the magnitude and density of surface charge as the net result of growth at high silica concentrations. Thus, Anabaena sp. appears to actively respond to growth in silicifying solutions by altering its surface properties in a manner that is likely to be manifested in nature by facilitated surface attachment. We conclude that potentiometric titrations reveal a Gram-negative bacterial surface whose properties are dynamic with respect to both nutrient and geochemical stressors.

Lalonde, S. V.; Smith, D. S.; Owttrim, G. W.; Konhauser, K. O.

2008-03-01

192

Roles of basolateral solute uptake via NKCC1 and of myosin II in vasopressin-induced cell swelling in inner medullary collecting duct  

PubMed Central

Collecting duct cells swell when exposed to arginine vasopressin (AVP) in the presence of a transepithelial osmolality gradient. We investigated the mechanisms of AVP-induced cell swelling in isolated, perfused rat inner medullary collecting ducts (IMCDs) using quantitative video microscopy and fluorescence-based measurements of transepithelial water transport. We tested the roles of transepithelial water flow, basolateral solute entry, and the cytoskeleton (actomyosin). When a transepithelial osmolality gradient was imposed by addition of NaCl to the bath, AVP significantly increased both water flux and cell height. When the osmolality gradient was imposed by addition of mannitol, AVP increased water flux but not cell height, suggesting that AVP-induced cell swelling requires a NaCl gradient and is not merely dependent on the associated water flux. Bumetanide (Na-K-2Cl cotransporter inhibitor) added to the bath markedly diminished the AVP-induced cell height increase. AVP-induced cell swelling was absent in IMCDs from NKCC1-knockout mice. In rat IMCDs, replacement of Na, K, or Cl in the peritubular bath caused significant cell shrinkage, consistent with a basolateral solute transport pathway dependent on all three ions. Immunocytochemistry using an antibody to NKCC1 confirmed basolateral expression in IMCD cells. The conventional nonmuscle myosin II inhibitor blebbistatin also diminished the AVP-induced cell height increase and cell shape change, consistent with a role for the actin cytoskeleton and myosin II. We conclude that the AVP-induced cell height increase is dependent on basolateral solute uptake via NKCC1 and changes in actin organization via myosin II, but is not dependent specifically on increased apical water entry.

Chou, Chung-Lin; Yu, Ming-Jiun; Kassai, Eliza M.; Morris, Ryan G.; Hoffert, Jason D.; Wall, Susan M.; Knepper, Mark A.

2008-01-01

193

Impact of Lewis Base on Chemical Reactivity and Separation Efficiency for Hydrated Fourth-Row Transition Metal (II) Complexes: An ONIOM DFT/MM Study.  

PubMed

In this paper, two-layer ONIOM combinations of high-level quantum mechanics (QM) and inexpensive molecular mechanics (MM) are successfully used to investigate the structural characters of metal (M, all the transition metals in the fourth period)-H2O-Lewis base (A(-)) complexes. Global and local descriptors of chemical reactivity and selectivity from conceptual density functional theory are employed to show the properties of the active complexes of M(H2O)2A2 and to study the effect of the Lewis base for the separation of transition metal ions. It is shown that chemical potential, hardness, electrophilicity, as well as the dual and multiphilic descriptors are adequate for characterizing the global and local reactivity trends of the M(H2O)2A2 complex. It is found that the reactivity is well localized at the metallic center in M(H2O)2A2 and the dual descriptor (?fM(r)) can also be used to characterize the directional attack of the electrophile and nucleophile except for the selectivity of the reaction. On the basis of the values of ?M and ?sk, and the sign of ?fM(r), the selectivity of the nucleophilic reagent (R(-)) for M(II) in M(H2O)2A2 (from high to low) follows this order: Cu(II) > Ni(II) > Co(II) > Fe(II) ? Mn(II) > Zn(II) > Cr(II). The Lewis base (A(-)) improves chemical reactivity and selectivity because of changing the reaction path and forming an intermediate, which possesses the higher antibonding character and the larger HOMO/LUMO gap. NBO or AIMALL analysis and Frontier orbital theory results presented here provided more theoretical support for the above reactivity and selectivity studies. PMID:24694190

He, Dingsheng; Ma, Ming

2014-04-24

194

The Chemical and Biological Effects of cis-Dichlorodiammineplatinum (II), an Antitumor Agent, on DNA  

PubMed Central

cis-Dichlorodiammineplatinum (II) binds irreversibly to the bases in DNA; the amount of platinum complex bound can be determined from changes in the ultraviolet absorption spectrum. As the ratio of platinum to phosphate is increased, an increasing inactivation of bacterial transforming DNA is observed. At a ratio that corresponds to spectrometric saturation, transforming activity is inactivated >105-fold. The trans isomer of the platinum complex, which is not effective against tumors, induces a similar inactivation of transforming DNA but with half the efficiency, indicating a different mode of binding. The sensitivity to inactivation by cis isomer varies slightly with the genetic marker assayed but is not dependent on the excision repair system. Uptake of DNA by competent cells is unaffected by bound platinum complex; however, integration of platinum-bound transforming DNA into the host genome decreases as the mole fraction of platinum increases. This loss of integration parallels the decreased transforming activity of the DNA. Although the drug induces interstrand crosslinks in DNA in vitro, these crosslinks are relatively rare events and cannot account for the observed inactivation.

Munchausen, Linda L.

1974-01-01

195

A physical chemical approach to understanding cellular dysfunction in type II diabetes  

NASA Astrophysics Data System (ADS)

The conversion of soluble protein into b-sheet rich amyloid fibers is the hallmark of a number of serious diseases. Precursors for many of these systems (e.g. Ab from Alzheimer's disease) reside in close association with a biological membranes. Membrane bilayers are reported to accelerate the rate of amyloid assembly. Furthermore, membrane permeabilization by amyloidogenic peptides can lead to toxicity. Given the b-sheet rich nature of mature amyloid, it is seemingly paradoxical that many precursors are either intrinsically b-helical, or transiently adopt an a-helical state upon association with membrane. We have investigated these phenomena in islet amyloid polypeptide (IAPP). IAPP is a 37-residue peptide hormone which forms amyloid fibers in individuals with type II diabetes. We report here the discovery of an oligomeric species that arises through stochastic nucleation on membranes, and results in disruption of the lipid bilayer. These species are stable, result in all-or-none leakage, and represent a definable protein/lipid phase that equilibrates over time. To characterize the reaction pathway of assembly, we apply an experimental design that includes ensemble and single particle evaluations in vitro and correlate these with quantitative measures of cellular toxicity.

Miranker, Andrew

2013-03-01

196

Chemical Characterization of Individual Particles and Residuals of Cloud Droplets and Ice Crystals Collected On Board Research Aircraft in the ISDAC 2008 Study  

SciTech Connect

Although it has been shown that size of atmospheric particles has a direct correlation with their ability to act as cloud droplet and ice nuclei, the influence of composition of freshly emitted and aged particles in nucleation processes is poorly understood. In this work we combine data from field measurements of ice nucleation with chemical imaging of the sampled particles to link aerosol composition with ice nucleation ability. Field measurements and sampling were conducted during the Indirect and Semidirect Aerosols Campaign (ISDAC) over Barrow, Alaska, in the springtime of 2008. In-situ ice nucleation measurements were conducted using a Continuous Flow Diffusion Chamber (CFDC). Measured number concentrations of ice nuclei (IN) varied from frequent values of 0.01 per liter to more than 10 per liter. Residuals of airborne droplets and ice crystals were collected through a counterflow virtual impactor (CVI). The compositions of individual atmospheric particles and the residuals were studied using Computer Controlled Scanning Electron Microscopy with Energy Dispersive X-ray analysis (CCSEM/EDX) and Scanning Transmission X-ray Microscopy coupled with Near Edge X-ray Absorption Fine Structure spectroscopy (STXM/NEXAFS). Chemical analysis of cloud particle residuals collected during an episode of high ice nucleation suggests that both size and composition may influence aerosol's ability to act as IN. The STXM/NEXAFS chemical composition maps of individual residuals have characteristic structures of either inorganic or black carbon cores coated by organic materials. In a separate flight, particle samples from a biomass burning plume were collected. Although it has previously been suggested that episodes of biomass burning contribute to increased numbers of highly effective ice nuclei, in this episode we observed that only a small fraction were effective ice nuclei. Most of the particles from the biomass plume episode were smaller in size and were composed of homogeneous organic material without identifiable cores.

Hiranuma, Naruki; Brooks, Sarah D.; Moffet, Ryan C.; Glen, Andrew; Laskin, Alexander; Gilles, Marry K.; Liu, Peter; MacDonald, A. M.; Strapp, J. Walter; McFarquhar, Greg

2013-06-24

197

The Chloroplast Function Database II: a comprehensive collection of homozygous mutants and their phenotypic/genotypic traits for nuclear-encoded chloroplast proteins.  

PubMed

The Chloroplast Function Database has so far offered phenotype information on mutants of the nuclear-encoded chloroplast proteins in Arabidopsis that pertains to >200 phenotypic data sets that were obtained from 1,722 transposon- or T-DNA-tagged lines. Here, we present the development of the second version of the database, which is named the Chloroplast Function Database II and was redesigned to increase the number of mutant characters and new user-friendly tools for data mining and integration. The upgraded database offers information on genome-wide mutant screens for any visible phenotype against 2,495 tagged lines to create a comprehensive homozygous mutant collection. The collection consists of 147 lines with seedling phenotypes and 185 lines for which we could not obtain homozygotes, as well as 1,740 homozygotes with wild-type phenotypes. Besides providing basic information about primer lists that were used for the PCR genotyping of T-DNA-tagged lines and explanations about the preparation of homozygous mutants and phenotype screening, the database includes access to a link between the gene locus and existing publicly available databases. This gives users access to a combined pool of data, enabling them to gain valuable insights into biological processes. In addition, high-resolution images of plastid morphologies of mutants with seedling-specific chloroplast defects as observed with transmission electron microscopy (TEM) are available in the current database. This database is used to compare the phenotypes of visually identifiable mutants with their plastid ultrastructures and to evaluate their potential significance from characteristic patterns of plastid morphology in vivo. Thus, the Chloroplast Function Database II is a useful and comprehensive information resource that can help researchers to connect individual Arabidopsis genes to plastid functions on the basis of phenotype analysis of our tagged mutant collection. It can be freely accessed at http://rarge.psc.riken.jp/chloroplast/. PMID:23230006

Myouga, Fumiyoshi; Akiyama, Kenji; Tomonaga, Yumi; Kato, Aya; Sato, Yuka; Kobayashi, Megumi; Nagata, Noriko; Sakurai, Tetsuya; Shinozaki, Kazuo

2013-02-01

198

Millimeter and submillimeter observations of the Orion Bar. II. Chemical models.  

NASA Astrophysics Data System (ADS)

Observations of 18 different molecules toward the Orion Bar are presented and analyzed to determine the chemical composition of this dense photon dominated region (PDR). In addition to molecules commonly found in dark clouds, the CO^+^ ion has definitely been identified. In contrast, no HOC^+^ is found, indicating an abundance ratio HCO^+^/HOC^+^>500. Chemical models are developed to explain the observed molecular column densities across the Orion Bar. These models include the geometrical, clumped structure derived in Paper I (Hogerheijde et al. 1995), which suggests that across the Bar, the PDR changes from a face-on to an edge-on geometry and back. It is found that the clumped structure does not affect the chemistry since the clumps contain only 10% of the material. The simplest model combining chemistry and geometry is therefore an one-dimensional homogeneous PDR at the face-on positions, and the same PDR convolved with the inferred geometry at the edge-on positions. This model produces column densities which are in good agreement with those derived from the observations. In particular, the observed trend that radicals such as CN and C_2_H have larger column densities close to the ionization front is well reproduced because these lines of sight sample a larger portion of the outer PDR where the radical abundances peak. In contrast, species such as SO are more prominent away from the ionization front, where the line of sight intersects more of the inner, shielded cloud. Only the column densities of H_2_S, SiO and CO^+^ cannot be reproduced by our models; all other species are well fitted. The results from two-dimensional calculations, which take the actual geometry and the clumps explicitly into account, are in good agreement with the one-dimensional case, justifying our simple approach. The most important difference between these models is the temperature structure, which is affected by the presence of dense clumps in the two-dimensional case and by scattering of photons from the wall of the cavity. The temperature is high - of order 1000K - at the outer PDR layers, and drops rapidly inward.

Jansen, D. J.; Spaans, M.; Hogerheijde, M. R.; van Dishoeck, E. F.

1995-11-01

199

Single particle chemical composition, state of mixing and shape of fresh and aged Saharan dust in Morocco and at Cape Verde Islands during SAMUM I and II  

Microsoft Academic Search

The Saharan Mineral Dust Experiment (SAMUM) is focussed to the understanding of the radiative effects of mineral dust. During the SAMUM 2006 field campaign at Tinfou, southern Morocco, chemical and mineralogical properties of fresh desert aerosol was measured. The winter campaign of Saharan Mineral Dust Experiment II in 2008 was based in Praia, Island of Santiago, Cape Verde. This second

Konrad Kandler; Carmen Emmel; Martin Ebert; Kirsten Lieke; Dörthe Müller-Ebert; Lothar Schütz; Stephan Weinbruch

2010-01-01

200

Quantum chemical topology study of the water-platinum(II) interaction.  

PubMed

The "inverse hydration" of neutral complexes of Pt(II) by an axial water molecule, whose one OH-bond is oriented toward Pt, has been the subject of recent works, theoretical as well as experimental. To study the influence of the ligands on this non-conventional H-bond, we extend here our previous energy calculations, using the second-order Moeller-Plesset perturbation theory (MP2) method together with the Dolg-Pélissier pseudopotential for platinum, to various neutral complexes including the well-known chemotherapeutic agent "cisplatin". The stabilization energy, depending on the nature and the configuration of platinum ligands, is dominated by the same important dispersive component, for all the investigated complexes. For a further characterization of this particular H-bond, we used the atoms in molecules theory (AIM) and the topological analysis of the electron localization function (ELF). The charge transfer occurring from the complex to the water molecule and the Laplacian of the density at the bond critical point between water and Pt are identified as interesting AIM descriptors of this non-conventional H-bond. Beyond this AIM analysis, we show that the polarization of the ELF bonding O-H basin involved in the non-conventional H-bond is enhanced during the approach of the water molecule to the Pt complexes. When the water medium, treated in an implicit solvation model, is taken into account, the interaction energies become independent on the nature and configuration of platinum ligands. However, the topological descriptors remain qualitatively unchanged. PMID:23347164

Bergès, Jacqueline; Fourré, Isabelle; Pilmé, Julien; Kozelka, Jiri

2013-02-01

201

Review of Catalytic Hydrogen Generation in the DWPF Chemical Processing Cell, Part II  

SciTech Connect

The Savannah River National Laboratory is in the process of investigating factors suspected of impacting catalytic hydrogen generation in the Defense Waste Processing Facility, DWPF, Chemical Process Cell, CPC. Noble metal catalyzed hydrogen generation in simulation work constrains the allowable acid addition operating window in DWPF. This constraint potentially impacts washing strategies during sludge batch preparation. It can also influence decisions related to the addition of secondary waste streams to a sludge batch. Catalytic hydrogen generation data from 2002-2005 were reviewed. The data came from process simulations of the DWPF Sludge Receipt and Adjustment Tank, SRAT, and Slurry Mix Evaporator, SME. Most of the data was from the development work for the Sludge Batch 3 process flowsheet. This included simulant and radioactive waste testing. Preliminary Sludge Batch 4 data were also reviewed. A statistical analysis of SB3 simulant hydrogen generation data was performed. One factor considered in the statistical analysis was excess acid. Excess acid was determined experimentally as the acid added beyond that required to achieve satisfactory nitrite destruction.

Koopman, David C.; Lambert, Daniel P.; Baich, Mark A.

2005-08-01

202

Chemical Composition of Two H II Regions in NGC 6822 Based on VLT Spectroscopy  

NASA Astrophysics Data System (ADS)

We present long slit spectrophotometry of regions V and X of the local group irregular galaxy NGC 6822. The data consist of VLT FORS observations in the 3450 to 7400 Å range. We have obtained electron temperatures and densities using different line intensity ratios. We have derived the H, He, C, and O abundances based on recombination lines; the abundance ratios among these elements are almost independent of the temperature structure of the nebulae. We have also determined the N, O, Ne, S, Cl, and Ar abundances based on collisionally excited lines; the ratios of these abundances relative to that of H depend strongly on the temperature structure of the nebulae. We compare the chemical composition of NGC 6822 V with those of the Sun, the Orion nebula, NGC 346 in the SMC, and 30 Doradus in the LMC. The O/H value derived from recombination lines for NGC 6822 V is in good agreement with the value derived by Venn et al. (2001) from A type supergiants in NGC 6822. MP received partial support from DGAPA UNAM (grant IN 114601). AP received partial support from DGAPA UNAM (grant IN 118405). MTR received partial support from FONDAP(15010003), a Guggenheim Fellowship and Fondecyt(1010404).

Peimbert, M.; Peimbert, A.; Ruiz, M. T.

2005-05-01

203

THE DUAL ORIGIN OF STELLAR HALOS. II. CHEMICAL ABUNDANCES AS TRACERS OF FORMATION HISTORY  

SciTech Connect

Fully cosmological, high-resolution N-body+smooth particle hydrodynamic simulations are used to investigate the chemical abundance trends of stars in simulated stellar halos as a function of their origin. These simulations employ a physically motivated supernova feedback recipe, as well as metal enrichment, metal cooling, and metal diffusion. As presented in an earlier paper, the simulated galaxies in this study are surrounded by stellar halos whose inner regions contain both stars accreted from satellite galaxies and stars formed in situ in the central regions of the main galaxies and later displaced by mergers into their inner halos. The abundance patterns ([Fe/H] and [O/Fe]) of halo stars located within 10 kpc of a solar-like observer are analyzed. We find that for galaxies which have not experienced a recent major merger, in situ stars at the high [Fe/H] end of the metallicity distribution function are more [{alpha}/Fe]-rich than accreted stars at similar [Fe/H]. This dichotomy in the [O/Fe] of halo stars at a given [Fe/H] results from the different potential wells within which in situ and accreted halo stars form. These results qualitatively match recent observations of local Milky Way halo stars. It may thus be possible for observers to uncover the relative contribution of different physical processes to the formation of stellar halos by observing such trends in the halo populations of the Milky Way and other local L{sup *} galaxies.

Zolotov, Adi; Hogg, David W. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Willman, Beth [Haverford College, Department of Astronomy, 370 Lancaster Avenue, Haverford, PA 19041 (United States); Brooks, Alyson M. [California Institute of Technology, M/C 350-17, Pasadena, CA 91125 (United States); Governato, Fabio [Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195 (United States); Shen, Sijing; Wadsley, James, E-mail: az481@nyu.ed, E-mail: bwillman@haverford.ed [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L88 4M1 (Canada)

2010-09-20

204

Single particle chemical composition and shape of fresh and aged Saharan dust in Morocco and at Cape Verde Islands during SAMUM I and II  

NASA Astrophysics Data System (ADS)

The Saharan Mineral Dust Experiment (SAMUM) is focussed to the understanding of the radiative effects of mineral dust. During the SAMUM 2006 field campaign at Tinfou, southern Morocco, chemical and mineralogical properties of fresh desert aerosols were measured. The winter campaign of Saharan Mineral Dust Experiment II was based in Praia, Island of Santiago, Cape Verde. This second field campaign was dedicated to the investigation of transported Saharan Mineral Dust. Aerosol particles between 100 nm and 500 ?m (Morocco) respectively 50 ?m (Cape Verde) in diameter were collected by nozzle and body impactors and in a sedimentation trap. The particles were investigated by electron microscopic single particle analysis and attached energy-dispersive X-ray analysis. Chemical properties as well as size and shape for each particle were recorded. Three size regimes are identified in the aerosol at Tinfou: Smaller than 500 nm in diameter, the aerosol consists of sulfates and mineral dust. Larger than 500 nm up to 50 ?m, mineral dust dominates, consisting mainly of silicates, and - to a lesser extent - carbonates and quartz. Larger than 50 ?m, approximately half of the particles consist of quartz. Time series of the elemental composition show a moderate temporal variability of the major compounds. Calcium-dominated particles are enhanced during advection from a prominent dust source in Northern Africa (Chott El Djerid and surroundings). At Praia, the boundary layer aerosol consists of a superposition of mineral dust, marine aerosol and ammonium sulfate, soot, and other sulfates as well as mixtures thereof. During low-dust periods, the aerosol is dominated by sea salt. During dust events, mineral dust takes over the majority of the particle mass up to 90 %. Particles smaller 500 nm in diameter always show a significant abundance of ammonium sulfate. The particle aspect ratio was measured for all analyzed particles. Its size dependence reflects that of the chemical composition. At Tinfou, larger than 500 nm particle diameter, a median aspect ratio of 1.6 is measured. Towards smaller particles, it decreases to about 1.3. Evaluation of the Cape Verde data will show whether a significant difference exists between fresh and aged Saharan dust in aspect ratio.

Kandler, K.; Lieke, K.; Schütz, L.; Deutscher, C.; Ebert, M.; Jaenicke, R.; Müller-Ebert, D.; Weinbruch, S.

2009-04-01

205

Chemical and toxicological characterization of residential oil burner emissions: II. Mutagenic, tumorigenic, and potential teratogenic activity.  

PubMed Central

Extracts of effluents from a modern residential oil burner have been evaluated in several toxicological assay systems. Bacterial mutagens were detected in extracts from both the particulate and vapor phase emissions. Effluents from continuous operation were an order of magnitude less mutagenic than those from cyclic (5 min on, 10 min off) operations. No difference in the yield of bacterial mutagens per gram of fuel burned was found between cyclic operation under low and moderate sooting conditions. On the basis of elution behavior from alumina it appeared that the bacterial mutagens collected from high sooting effluents were more polar than those from low sooting effluent. An extract that was mutagenic in bacteria did not induce a significant increase in mutation frequency to human lymphoblasts. No evidence of tumorigenicity was observed in a limited number of newborn mice after IP injection of effluent extract when compared to historical control data. Putative nonmutagenic teratogens were detected in effluent using an attachment inhibition assay. The level of these agents was reduced in effluents from continuous oil burner operation.

Braun, A G; Busby, W F; Liber, H L; Thilly, W G

1987-01-01

206

A multimedia fate and chemical transport modeling system for pesticides: II. Model evaluation  

NASA Astrophysics Data System (ADS)

Pesticides have adverse health effects and can be transported over long distances to contaminate sensitive ecosystems. To address problems caused by environmental pesticides we developed a multimedia multi-pollutant modeling system, and here we present an evaluation of the model by comparing modeled results against measurements. The modeled toxaphene air concentrations for two sites, in Louisiana (LA) and Michigan (MI), are in good agreement with measurements (average concentrations agree to within a factor of 2). Because the residue inventory showed no soil residues at these two sites, resulting in no emissions, the concentrations must be caused by transport; the good agreement between the modeled and measured concentrations suggests that the model simulates atmospheric transport accurately. Compared to the LA and MI sites, the measured air concentrations at two other sites having toxaphene soil residues leading to emissions, in Indiana and Arkansas, showed more pronounced seasonal variability (higher in warmer months); this pattern was also captured by the model. The model-predicted toxaphene concentration fraction on particles (0.5-5%) agrees well with measurement-based estimates (3% or 6%). There is also good agreement between modeled and measured dry (1:1) and wet (within a factor of less than 2) depositions in Lake Ontario. Additionally this study identified erroneous soil residue data around a site in Texas in a published US toxaphene residue inventory, which led to very low modeled air concentrations at this site. Except for the erroneous soil residue data around this site, the good agreement between the modeled and observed results implies that both the US and Mexican toxaphene soil residue inventories are reasonably good. This agreement also suggests that the modeling system is capable of simulating the important physical and chemical processes in the multimedia compartments.

Li, Rong; Scholtz, M. Trevor; Yang, Fuquan; Sloan, James J.

2011-07-01

207

Contact of clay-liner materials with acidic tailings. II. Chemical modeling  

SciTech Connect

The ion speciation-solubility model WATEQ3 was used to model original aqueous solutions and solutions resulting from liner materials contacted with uranium mill tailings, synthetic mill tailings or H/sub 2/SO/sub 4/. The modeling results indicate solution species which are in apparent equilibrium with respect to particular solids. These solids provide potential solubility controls for their corresponding dissolved constituents. The disequilibrium indices computed by WATEQ3 indicate amorphic Fe(OH)/sub 3/(A), Al0HO/sub 4/, alunite (KA1/sub 3/(SO/sub 4/)/sub 2/(OH)/sub 6/), gypsum (CaSO/sub 4/ . 2H/sub 2/O), celestite (SrSO/sub 4/), anglesite (PbSO/sub 4/) and MnHPO/sub 4/ may have precipitated in the contacted liner materials and may also provide solubility controls for their dissolved constituents. The disequilibrium indices also show that the solutions resulting from the interaction of Highland Mill tailings are oversaturated with K-, H-, and Na-jarosites ((K,H,Na)Fe/sub 3/(SO/sub 4/)/sub 2/(OH)/sub 6/). Because jarosite has been identified by x-ray diffraction as a precipitate in these reacted liner materials, it would appear that there is a kinetic barrier which prohibits jarosite from being an effective solubility control. Results of this study also show that the solubilities of many solid phases were pH dependent. This exploratory use of geochemical modeling has demonstrated its capability to test solubility hypotheses for clay liners reacted with tailings solutions and to guide the analyses of important constituents and parameters for these solutions. Geochemical modeling can be used, in parallel with characterization techniques for the solid phases, to support the presence of the solid phase and to guide the search for further solid phases. Geochemical modeling is also an effective tool in delineating the chemical causes for changes in permeability of liner materials.

Peterson, S.R.; Krupka, K.M.

1981-09-01

208

Half-sandwich RuII-[9]aneS3 complexes with dicarboxylate ligands: synthesis, characterization and chemical behavior.  

PubMed

With the aim of further developing the structure-activity relationship in biologically active half-sandwich Ru(ii)-[9]aneS(3) complexes ([9]aneS(3)=1,4,7-trithiacyclononane), a series of new mono- and dinuclear complexes bearing the chelating dicarboxylate ligands oxalate (ox), malonate (mal) and methylmalonate (mmal), have been synthesized and studied. Treatment of the precursor [Ru([9]aneS(3))(dmso)(3)][CF(3)SO(3)](2) (7) with equivalent amounts of K(2)(dicarb) afforded the corresponding neutral complexes with the general formula [Ru([9]aneS(3))(dmso-S)(eta(2)-dicarb)] (where dicarb=ox (1), mal (2) and mmal (3)), while using half an equivalent of K(2)(ox), the symmetric dimer [{Ru([9]aneS(3))(dmso-S)}(2)(mu-eta(4)-ox)][CF(3)SO(3)](2) (4) was isolated. The reaction of with the oxalato complex fac-[Ru(dmso-S)(3)(dmso-O)(eta(2)-ox)] (9) yielded two asymmetric dimers, namely [{Ru([9]aneS(3))(dmso-S)}(mu-eta(4)-ox){fac-Ru(dmso-S)(3)(CF(3)SO(3))}][CF(3)SO(3)] (5) and [{Ru([9]aneS(3))(dmso-S)}(mu-eta(4)-ox){fac-Ru(dmso-S)(3)(dmso-O)}][CF(3)SO(3)](2) (6), depending on the reaction conditions. All new complexes were structurally characterized, both in solution (by NMR spectroscopy) and in the solid state (by X-ray crystallography). The chemical behavior of the complexes in aqueous solution was studied by UV-Vis and NMR spectroscopy in view of their potential antitumor activity: the monomers partially release a dmso ligand to yield the monofunctional aqua adduct [Ru([9]aneS(3))(eta(2)-dicarb)(H(2)O)], while the dimers rapidly open up the oxalato bridge to give two mononuclear fragments. Splitting of the asymmetric dimers 5 and 6 occurs selectively and the ox moiety remains bonded to the fac-Ru(dmso-S)(3) fragment. A detailed comparison of the structural and chemical features of 1-6 with those of similar dicarboxylate complexes possessing the fac-Ru(dmso-S)(3) fragment in place of Ru([9]aneS(3)) allows us to draw a number of general conclusions on the binding preferences of dicarb ligands on the octahedral Ru(II) center. PMID:17828366

Bratsos, Ioannis; Birarda, Giovanni; Jedner, Stephanie; Zangrando, Ennio; Alessio, Enzo

2007-09-28

209

Chemical characterization of individual particles and residuals of cloud droplets and ice crystals collected on board research aircraft in the ISDAC 2008 study  

NASA Astrophysics Data System (ADS)

Ambient particles and the dry residuals of mixed-phase cloud droplets and ice crystals were collected during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) near Barrow, Alaska, in spring of 2008. The collected particles were analyzed using Computer Controlled Scanning Electron Microscopy with Energy Dispersive X-ray analysis and Scanning Transmission X-ray Microscopy coupled with Near Edge X-ray Absorption Fine Structure spectroscopy to identify physico-chemical properties that differentiate cloud-nucleating particles from the total aerosol population. A wide range of individually mixed components was identified in the ambient particles and residuals including organic carbon compounds, inorganics, carbonates, and black carbon. Our results show that cloud droplet residuals differ from the ambient particles in both size and composition, suggesting that both properties may impact the cloud-nucleating ability of aerosols in mixed-phase clouds. The percentage of residual particles which contained carbonates (47%) was almost four times higher than those in ambient samples. Residual populations were also enhanced in sea salt and black carbon and reduced in organic compounds relative to the ambient particles. Further, our measurements suggest that chemical processing of aerosols may improve their cloud-nucleating ability. Comparison of results for various time periods within ISDAC suggests that the number and composition of cloud-nucleating particles over Alaska can be influenced by episodic events bringing aerosols from both the local vicinity and as far away as Siberia.

Hiranuma, N.; Brooks, S. D.; Moffet, R. C.; Glen, A.; Laskin, A.; Gilles, M. K.; Liu, P.; MacDonald, A. M.; Strapp, J. W.; McFarquhar, G. M.

2013-06-01

210

Correlations between genetic, morphological, and chemical diversities in a germplasm collection of the medicinal plant Origanum vulgare L.  

PubMed

In total, 42 accessions of Origanum vulgare L., mostly originating from Europe, were evaluated, to detect molecular, quantitative morphological, and chemotype polymorphisms and to discover possible correlations between them. Twelve traits related to morphological characteristics were measured. The components in the essential oils were identified by GC/MS analysis, and the oil contents of 18 major compounds were determined. A total of 477 molecular polymorphisms including 214 AFLP (amplified fragment length polymorphism) and 263 SAMPL (selectively amplified microsatellite polymorphic loci) were used for genotyping. Euclidean distances of morphological and chemotypic data and genetic distances (1 - Dice's similarity) of molecular markers were compared by applying Mantel tests to ascertain the congruencies between them. A relatively high correlation between chemotypic patterns and genetic markers was identified, while a lower correlation was found between the morphological and genetic matrices. Pairwise analyses of correlation among all traits showed that the stem diameter was correlated to the essential-oil yield and the carvacrol content. Cluster analysis, population inference, and principal component analysis revealed a broad genetic and chemical variation among the accessions. The knowledge of these diversities, found in this study, will allow a plant improvement of Origanum vulgare related to pharmaceutical and spice uses. PMID:23255448

Azizi, Ali; Hadian, Javad; Gholami, Mansour; Friedt, Wolfgang; Honermeier, Bernd

2012-12-01

211

Theoretical Investigation of the Magnetic Exchange Interactions in Copper(II) Oxides under Chemical and Physical Pressures  

PubMed Central

It remains a challenge to understand the unconventional mechanisms that cause high-TC superconductivity in cuprate superconductors, high-TC multiferroicity in CuO, or low-dimensional magnetism in the spin-Peierls transition compounds such as CuGeO3. A common feature of all these copper oxide compounds (containing Cu2+ ions) is the presence of large magnetic superexchange interactions J. It is a general strategy to apply chemical and/or physical pressure in order to tune these exotic properties. Here we show theoretically, for the first time, the impact of physical pressure on J on CuO, for which we predict a strong enhancement of the low-dimensionality of the magnetic interactions and the spin-frustration at high-pressures. Such modifications are expected to strongly influence the multiferroic properties of CuO. We finally demonstrate that PBE0 hybrid DFT calculations provide reliable J values for a wide range of copper(II) oxides compounds, i.e. CuGeO3, BaCu2Si2O7, BaCu2Ge2O7, and La2CuO4.

Rocquefelte, Xavier; Schwarz, Karlheinz; Blaha, Peter

2012-01-01

212

Vermont SIRI MSDS Collection  

NSDL National Science Digital Library

From Vermont Safety Information Resources, Inc., this searchable material safety data sheets collection can be searched by company or compound name. Visitors can also search for toxicology reports by chemical name, chemical trade name, or the CAS or RTECS number.

2009-07-14

213

Water-quality data-collection activities in Colorado and Ohio; Phase II, Evaluation of 1984 field and laboratory quality-assurance practices  

USGS Publications Warehouse

Serious questions have been raised by Congress about the usefulness of water quality data for addressing issues of regional and national scope and, especially, for characterizing the current quality of the Nation 's streams and groundwater. In response, the U.S. Geological Survey conducted a pilot study in Colorado and Ohio to: (1) determine the characteristics of current (1984) water quality data collection activities of Federal, regional, State, and local agencies, and academic institutions; and (2) determine how well the data from these activities, collected for various purposes and using different procedures, can be used to improve the ability to answer major broad scope questions, such as: what are (or were) natural or near-natural water quality conditions; what are existing water quality conditions; and, how water quality has changed and how the changes relate to human activities. Colorado and Ohio were chosen for the pilot study largely because they represent regions with different types of water quality concerns and programs. The study has been divided into three phases, the objectives of which are: Phase I - Inventory water quality data collection programs, including costs, and identify those programs that met a set of broad criteria for producing data that are potentially appropriate for water quality assessments of regional and national scope. Phase II - Evaluate the quality assurance of field and laboratory procedures used in producing the data from programs that met the broad criteria of Phase I. Phase III - Compile the qualifying data and evaluate the adequacy of this data base for addressing selected water quality questions of regional and national scope. (Author 's abstract)

Childress, C. J.; Chaney, T. M.; Myers, Donna; Norris, J. M.; Hren, Janet

1987-01-01

214

Complex formation, chemical exchange, species structure, and stereoselective effects in the copper(II)-L/DL-histidine systems.  

PubMed

The formation of copper(II) complexes with L- and DL-histidine (HisH) has been studied by means of pH-potentiometry and spectrophotometry over a wide range of pH (2-14), ligand-to-metal ratio (1?:?1-15?:?1), and temperature (15-55 °C) in aqueous solutions with 1.0 mol dm(-3) KNO(3) as background. Formation constants and spectral characteristics of 13 complex types were found. Fine stereoselective effects have been detected with preferential coordination of two ligands with identical configuration in Cu(His)(HisH)(+) and opposite configuration in Cu(His)(2). The stereoselective effect for Cu(His)(HisH)(+) is explained by hydrogen bond formation between the carboxyl and imidazolyl groups of neighboring ligands at cis-arrangement of amino groups (3N(eq)-form). The opposite sign of stereoselective effect for Cu(His)(2) is derived from favourable axial coordination of the imidazole group in meso-form with cis-structure (3N(eq)N(ax)-form). A significant tetrahedral distortion was revealed for the first time in the prevalent cis-isomer of the Cu(L-His)(2) 4N(eq)-form. These findings were confirmed by EPR data and DFT computations at the B3LYP/TZVP level. The prevalence of cis-isomers for these complexes has been assigned to the rather strong trans effect of the amino groups. The structures of other detected complexes are briefly discussed on the basis of spectroscopic data. Chemical exchange reactions in the copper(II)-L/DL-hishidine systems have been investigated by the NMR relaxation of water protons. A unique proton exchange reaction with short-term proton dissociation from the coordinated imidazolyl group catalyzed by hydroxide ion was characterised for the first time. The discovered enantioselective effects in the ligand exchange reactions between Cu(His)(2) and HisH or His(-) species were attributed to the associative substitution mechanism. PMID:22120906

Shtyrlin, Valery G; Zyavkina, Yulia I; Gilyazetdinov, Edward M; Bukharov, Mikhail S; Krutikov, Alexander A; Garipov, Ruslan R; Mukhtarov, Anvar S; Zakharov, Alexey V

2012-01-28

215

Chemical composition of size-segregated aerosol collected all year-round at Concordia Station (Dome C, Antarctica). Transport processes and climatic implications.  

NASA Astrophysics Data System (ADS)

Ice-core stratigraphies of chemical components of atmospheric gases and aerosols trapped in the snow layers by scavenging processes are a powerful tool in understanding past climatic and environmental changes. The deep ice core drilled at Dome C in the framework of the EPICA project allowed reconstructing the last 8 glacial-interglacial cycles and highlightened the complex relationships between climatic forcings and environmental feedback processes. In interpreting ice core records as a function of past climatic variations, some difficulties arise from uncertainties in considering selected chemical species as reliable markers of climatic and environmental processes and in attributing the different load and composition of aerosols over Antarctica to changes in source intensity (such as aridity, wind strength, emersion of continental platform by sea-level lowering etc..) and/or to variations in atmospheric processes (such as meridional and zonal atmospheric circulation, polar vortex intensity, scavenging efficiency, transport pathways etc..). Besides, two new aspects are actually under discussions: the possible use of Na as sea-ice cover marker (via frost flower formation on the sea-ice surface during the pack-ice formation) and the identification of continental source areas for mineral dust reaching internal regions of Antarctica during glacial and interglacial periods. In order to better address such controversial issues, since 2005 a continuous, high temporal resolution size-segregated aerosol and surface snow sampling has been performed at Dome C (central East Antarctic Plateau, 75° 06' S, 123° 23' E), in the framework of "Station Concordia" Project (a Italian PNRA- French IPEV joint program). The chemical analysis of size-segregated aerosol and daily superficial snow samples, collected all year-round for more than 4 years, can contribute to clarify some of the above mentioned topics. In particular: the possible seasonal pattern of sea spray aerosol could be related to sea-ice formation timing and/or to changes in zonal wind intensity and atmospheric pathway; the mineralogical analysis of insoluble dust particles can allow the identification of continental sources, by comparison with soils collected in the potential source areas (PSAs); finally, the seasonal pattern of biogenic markers (such as methanesulphonic acid and non-sea-salt sulphate) can be linked to sea surface temperature, sea-ice cover and southern-hemisphere circulation modes (e.g., SOI, AAO or SAM and ACW). As regard as depositional and post-depositional processes, the analysis of chemical markers in aerosol, superficial snow and hoar crystals, sampled contemporaneously, will allow understanding the key factors (e.g., snow acidity, solar irradiation) affecting the preservation of components reversibly fixed in the snow layers (such as, for instance, methanesulphonic acid, nitrate and chloride). A summary of the major results from the chemical analysis of aerosol and snow collected at Dome C is here presented.

Udisti, Roberto; Becagli, Silvia; Frosini, Daniele; Galli, Gaia; Ghedini, Costanza; Rugi, Francesco; Severi, Mirko; Traversi, Rita

2010-05-01

216

Reduced in vitro toxicity of fine particulate matter collected during the 2008 Summer Olympic Games in Beijing: the roles of chemical and biological components.  

PubMed

Beijing has implemented systematic air pollution control legislation to reduce particulate emissions and improve air quality during the 2008 Summer Olympics, but whether the toxicity of fine fraction of particles (PM(2.5)) would be changed remains unclear. In present study we compared in vitro biological responses of PM(2.5) collected before and during the Olympics and tried to reveal possible correlations between its chemical components and toxicological mechanism(s). We measured cytotoxicity, cytokines/chemokines, and related gene expressions in murine alveolar macrophages, MH-S, after treated with 20 PM(2.5) samples. Significant, dose-dependent effects on cell viability, cytokine/chemokine release and mRNA expressions were observed. The cytotoxicity caused at equal mass concentration of PM(2.5) was notably reduced (p<0.05) by control measures, and significant association was found for viability and elemental zinc in PM(2.5). Endotoxin content in PM(2.5) correlated with all of the eight detected cytokines/chemokines; elemental and organic carbon correlated with four; arsenic and chromium correlated with six and three, respectively; iron and barium showed associations with two; nickel, magnesium, potassium, and calcium showed associations with one. PM(2.5) toxicity in Beijing was substantially dependent on its chemical components, and lowering the levels of specific components in PM(2.5) during the 2008 Olympics resulted in reduced biological responses. PMID:23962744

Shang, Yu; Zhu, Tong; Lenz, Anke-Gabriele; Frankenberger, Birgit; Tian, Feng; Chen, Chenyong; Stoeger, Tobias

2013-10-01

217

Chemical characterisation of organic functional group compositions in PM2.5 collected at nine administrative provinces in northern Thailand during the Haze Episode in 2013.  

PubMed

Along with rapid economic growth and enhanced agricultural productivity, particulate matter emissions in the northern cities of Thailand have been increasing for the past two decades. This trend is expected to continue in the coming decade. Emissions of particulate matter have brought about a series of public health concerns, particularly chronic respiratory diseases. It is well known that lung cancer incidence among northern Thai women is one of the highest in Asia (an annual age-adjusted incidence rate of 37.4 per 100,000). This fact has aroused serious concern among the public and the government and has drawn much attention and interest from the scientific community. To investigate the potential causes of this relatively high lung cancer incidence, this study employed Fourier transform infrared spectroscopy (FTIR) transmission spectroscopy to identify the chemical composition of the PM2.5 collected using Quartz Fibre Filters (QFFs) coupled with MiniVolTM portable air samplers (Airmetrics). PM2.5 samples collected in nine administrative provinces in northern Thailand before and after the "Haze Episode" in 2013 were categorised based on three-dimensional plots of a principal component analysis (PCA) with Varimax rotation. In addition, the incremental lifetime exposure to PM2.5 of both genders was calculated, and the first derivative of the FTIR spectrum of individual samples is here discussed. PMID:23886161

Pongpiachan, Siwatt; Choochuay, Chomsri; Chalachol, Jittipan; Kanchai, Panatda; Phonpiboon, Tidarat; Wongsuesat, Sornsawan; Chomkhae, Kanokwan; Kittikoon, Itthipon; Hiranyatrakul, Phoosak; Cao, Junji; Thamrongthanyawong, Sombat

2013-01-01

218

Water and Sediment Chemical Data and Data Summary for Samples Collected in 1999 and 2001 in the Goodpaster River Basin, Big Delta B-2 Quadrangle, Alaska  

USGS Publications Warehouse

We report the chemical analysis for water and sediment collected from the Big Delta B-2 quadrangle. These data are part of a study located in the Big Delta B-2 quadrangle that focused on the integration of geology and bedrock geochemistry on with the biogeochemistry of water, sediments, soil, and vegetation. The discovery of the Pogo lode gold deposit in the northwest corner of the quadrangle was the impetus for this study. The study objectives were to create a geologic map, evaluate the bedrock geochemical influence on the geochemical signature of the surficial environment, and define landscape-level predevelopment geochemical baselines. Important to baseline development is an evaluation of what, if any, geochemical difference exists between the mineralized and non-mineralized areas within a watershed or between mineralized and non-mineralized watersheds. The analytic results for the bedrock, soils, and vegetation are reported elsewhere. Presented here, with minimal interpretation, is the analytic data for the water and sediment samples collected in the summers of 1999 and 2001, and a summary statistics of these analyses.

Wang, Bronwen; Gough, Larry; Wanty, Richard; Vohden, Jim; Crock, Jim; Day, Warren

2006-01-01

219

Chemical nature and molecular weight distribution of the water-soluble fine and ultrafine PM fractions collected in a rural environment  

NASA Astrophysics Data System (ADS)

PM1-2.5, PM0.1-1, and PM<0.1 water-soluble organic carbon (WSOC) fractions of aerosol samples collected during summer and fall 2009 were analyzed by UV/VIS spectroscopy and electrospray ionization-mass spectrometry (ESI/MS). The focus of this study was to compare optical properties, chemical nature, and molecular weight distribution in samples extracted from different size fractions and collected during different seasons (fall vs. summer). Diurnal patterns were also investigated. An increase in absorptivity, aromaticity, and average molecular weight (AMW) in all size fractions found in the fall samples indicates different formation processes for the organic carbon between the summer and fall periods. The fall ultrafine fraction (PM<0.1) demonstrated characteristics different from the other two PM size fractions and more similar to aquatic fulvic acids. It had the highest HULIS/WSOC ratio, molar absorptivity, and AMWs up to about 700 Da when analyzed by the UV/VIS method and about 475 Da by the ESI/MS. Higher concentrations of organosulfate (OS) compounds and polycarboxylic acids were detected in the summer samples while organonitrate (ON) compounds and monocarboxylic acids were higher in the fall samples.

Pavlovic, J.; Hopke, P. K.

2012-11-01

220

Investigation of the maximum quantum yield of PS II in Haematococcus pluvialis cell cultures during growth: effects of chemical or high-intensity light treatment.  

PubMed

In this study, we investigated the increase in photosynthetic quantum yield that occurs in advance of increased microalgal growth. Haematococcus pluvialis was cultivated under normal conditions; the number of cells, the maximum quantum yield of photosystem II (F(v)/F(m)), and optical density were measured. We observed an increase in F(v)/F(m) approximately 72h prior to the cell growth phase. To confirm the relationship between photosynthetic yield and growth, samples were treated with several chemicals under high-intensity light illumination and control conditions to inhibit photosystem II and induce a decrease in the quantum photosynthetic yield. The samples were exposed to high-intensity light at an irradiance of 400?mol photonsm(-2)s(-1) for varied amount of time and were treated with chemicals such as 3-(3,4-dichlorophenyl)-1,1-dimethylurea, nigericin sodium salt and valinomycin. We observed that both the photooxidation of photosystem II reaction centers and the formation of transmembrane electrochemical gradients led to an initial decrease in fluorescence yield after the onset of high-intensity light illumination. We also observed that treatment of high-intensity light illuminated cells with antibiotics after adaptation to moderate light intensities caused a difference in photosynthetic activity. In conclusion, the maximum quantum yield of photosystem II is obtained prior to the cell growth phase and can therefore be used as a prediction parameter for cell growth. PMID:21592814

Wang, Hui-Chih; Cho, Man-Gi; Riznichenko, Galina; Rubin, Andrey B; Lee, Ji-Hyun

2011-09-01

221

Chemical constituents and free radical scavenging activity of corn pollen collected from Apis mellifera hives compared to floral corn pollen at Nan, Thailand  

PubMed Central

Background Bee pollen is composed of floral pollen mixed with nectar and bee secretion that is collected by foraging honey (Apis sp.) and stingless bees. It is rich in nutrients, such as sugars, proteins, lipids, vitamins and flavonoids, and has been ascribed antiproliferative, anti-allergenic, anti-angiogenic and free radical scavenging activities. This research aimed at a preliminary investigation of the chemical constituents and free radical scavenging activity in A. mellifera bee pollen. Methods Bee pollen was directly collected from A. mellifera colonies in Nan province, Thailand, in June, 2010, whilst floral corn (Zea mays L.) pollen was collected from the nearby corn fields. The pollen was then sequentially extracted with methanol, dichloromethane (DCM) and hexane, and each crude extract was tested for free radical scavenging activity using the DPPH assay, evaluating the percentage scavenging activity and the effective concentration at 50% (EC50). The most active crude fraction from the bee pollen was then further enriched for bioactive components by silica gel 60 quick and adsorption or Sephadex LH-20 size exclusion chromatography. The purity of all fractions in each step was observed by thin layer chromatography and the bioactivity assessed by the DPPH assay. The chemical structures of the most active fractions were analyzed by nuclear magnetic resonance. Results The crude DCM extract of both the bee corn pollen and floral corn pollen provided the highest active free radical scavenging activity of the three solvent extracts, but it was significantly (over 28-fold) higher in the bee corn pollen (EC50?=?7.42 ± 0.12 ?g/ml), than the floral corn pollen (EC50?=?212 ± 13.6% ?g/ml). After fractionation to homogeneity, the phenolic hydroquinone and the flavone 7-O-R-apigenin were found as the minor and major bioactive compounds, respectively. Bee corn pollen contained a reasonably diverse array of nutritional components, including biotin (56.7 ?g/100 g), invert sugar (19.9 g/100 g), vitamin A and ? carotene (1.53 mg/100 g). Conclusions Bee pollen derived from corn (Z. mays), a non-toxic or edible plant, provided a better free radical scavenging activity than floral corn pollen.

2012-01-01

222

Unsymmetrical Fe(III)Co(II) and Ga(III)Co(II) complexes as chemical hydrolases: biomimetic models for purple acid phosphatases (PAPs).  

PubMed

The design and development of suitable biomimetic catalytic systems capable of mimicking the functional properties of enzymes continues to be a challenge for bioinorganic chemists. In this study, we report on the synthesis, X-ray structures, and physicochemical characterization of the novel isostructural [Fe(III)Co(II)(BPBPMP)(mu-OAc)(2)]ClO(4) (1) and [Ga(III)Co(II)(BPBPMP)(mu-OAc)(2)]ClO(4) (2) complexes with the unsymmetrical dinucleating ligand H(2)BPBPMP (2-bis[{(2-pyridyl-methyl)-aminomethyl}-6-{(2-hydroxy-benzyl)-(2-pyridyl-methyl)}-aminomethyl]-4-methylphenol). The previously reported complex [Fe(III)Zn(II)(BPBPMP)(mu-OAc)(2)]ClO(4) (3) was investigated here by electron paramagnetic resonance for comparison with such studies on 1 and 2. A magneto-structural correlation between the exchange parameter J (cm(-1)) and the average bond lengh d (A) of the [Fe(III)-O-M(II)] structural unit for 1 and for related isostructural Fe(III)M(II) complexes using the correlation J = -10(7) exp(-6.8d) reveals that this parameter is the major factor that determines the degree of antiferromagnetic coupling in the series [(BPBPMP)Fe(III)(mu-OAc)(2)M(II)](+) (M(II) = Mn, Fe, Co, Ni) of complexes. Potentiometric and spectrophotometric titrations along with electronic absorption studies show that, in aqueous solution, complexes 1 and 2 generate the [(HO)M(III)(mu-OH)Co(II)(H(2)O)] complex as the catalytically active species in diester hydrolysis reactions. Kinetic studies on the hydrolysis of the model substrate bis(2,4-dinitrophenyl)phosphate by 1 and 2 show Michaelis-Menten behavior, with 2 being 35% more active than 1. In combination with k(H)/k(D) isotope effects, the kinetic studies suggest a mechanism in which a terminal M(III)-bound hydroxide is the hydrolysis-initiating nucleophilic catalyst. In addition, the complexes show maximum catalytic activity in DNA hydrolysis near physiological pH. The modest reactivity difference between 1 and 2 is consistent with the slightly increased nucleophilic character of the Ga(III)-OH terminal group in comparison to Fe(III)-OH in the dinuclear M(III)Co(II) species. PMID:19603814

Xavier, Fernando R; Neves, Ademir; Casellato, Annelise; Peralta, Rosely A; Bortoluzzi, Adailton J; Szpoganicz, Bruno; Severino, Patricia C; Terenzi, Hernán; Tomkowicz, Zbigniew; Ostrovsky, Sergei; Haase, Wolfgang; Ozarowski, Andrew; Krzystek, Jerzy; Telser, Joshua; Schenk, Gerhard; Gahan, Lawrence R

2009-08-17

223

The catalytic stripping voltammetre of trace copper (II) at a chemically modified electrode on oxine containing carbon paste  

Microsoft Academic Search

Summary  An oxine modified electrode is prepared qn the basis of carbon paste. The process is rapid and simple. The catalytic stripping\\u000a voltammetric characteristic of Cu (II) on the modified electrode was studied and the method has been applied to the determination\\u000a of trace Cu (II), and there was good linear relationship between the concentration of Cu (II) and the peak

Qiao Wen-jian; Dina Hong

1993-01-01

224

Collective Properties of Neutron-star X-Ray Binary Populations of Galaxies. II. Pre-low-mass X-Ray Binary Properties, Formation Rates, and Constraints  

NASA Astrophysics Data System (ADS)

We continue our exploration of the collective properties of neutron-star X-ray binaries in the stellar fields (i.e., outside globular clusters) of normal galaxies. In Paper I of this series, we considered high-mass X-ray binaries (HMXBs). In this paper (Paper II), we consider low-mass X-ray binaries (LMXBs), whose evolutionary scenario is very different from that of HMXBs. We consider the evolution of primordial binaries up to the stage where the neutron star just formed in the supernova explosion of the primary is in a binary with its low-mass, unevolved companion, and this binary has circularized tidally, producing what we call a pre-low-mass X-ray binary (pre-LMXB). We study the constraints on the formation of such pre-LMXBs in detail (since these are low-probability events), and calculate their collective properties and formation rates. To this end, we first consider the changes in the binary parameters in the various steps involved, viz., the common-envelope phase, the supernova, and the tidal evolution. This naturally leads to a clarification of the constraints. We then describe our calculation of the evolution of the distributions of primordial binary parameters into those of pre-LMXB parameters, following the standard evolutionary scenario for individual binaries. We display the latter as both bivariate and monovariate distributions, discuss their essential properties, and indicate the influences of some essential factors on these. Finally, we calculate the formation rate of these pre-LMXBs. The results of this paper will be used in a subsequent one to compute the expected X-ray luminosity function of LMXBs.

Bhadkamkar, H.; Ghosh, P.

2014-04-01

225

Chemically modified activated carbon with 1-acylthiosemicarbazide for selective solid-phase extraction and preconcentration of trace Cu(II), Hg(II) and Pb(II) from water samples.  

PubMed

A new sorbent 1-acylthiosemicarbazide-modified activated carbon (AC-ATSC) was prepared as a solid-phase extractant and applied for removing of trace Cu(II), Hg(II) and Pb(II) prior to their determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The separation/preconcentration conditions of analytes were investigated, including effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. At pH 3, the maximum static adsorption capacity of Cu(II), Hg(II) and Pb(II) onto the AC-ATSC were 78.20, 67.80 and 48.56 mg g(-1), respectively. The adsorbed metal ions were quantitatively eluted by 3.0 mL of 2% CS(NH2)2 and 2.0 mol L(-1) HCl solution. Common coexisting ions did not interfere with the separation. According to the definition of IUPAC, the detection limits (3sigma) of this method for Cu(II), Hg(II) and Pb(II) were 0.20, 0.12 and 0.45 ng mL(-1), respectively. The relative standard deviation under optimum conditions is less than 4.0% (n=8). The prepared sorbent was applied for the preconcentration of trace Cu(II), Hg(II) and Pb(II) in certified and water samples with satisfactory results. PMID:19643535

Gao, Ru; Hu, Zheng; Chang, Xijun; He, Qun; Zhang, Lijun; Tu, Zhifeng; Shi, Jianping

2009-12-15

226

Electrochromic and colorimetric properties of nickel(II) oxide thin films prepared by aerosol-assisted chemical vapor deposition.  

PubMed

Aerosol-assisted chemical vapor deposition (AACVD) was used for the first time in the preparation of thin-film electrochromic nickel(II) oxide (NiO). The as-deposited films were cubic NiO, with an octahedral-like grain structure, and an optical band gap that decreased from 3.61 to 3.48 eV on increase in film thickness (in the range 500-1000 nm). On oxidative voltammetric cycling in aqueous KOH (0.1 mol dm(-3)) electrolyte, the morphology gradually changed to an open porous NiO structure. The electrochromic properties of the films were investigated as a function of film thickness, following 50, 100, and 500 conditioning oxidative voltammetric cycles in aqueous KOH (0.1 mol dm(-3)). Light modulation of the films increased with the number of conditioning cycles. The maximum coloration efficiency (CE) for the NiO (transmissive light green, the "bleached" state) to NiOOH (deep brown, the colored state) electrochromic process was found to be 56.3 cm(2) C(-1) (at 450 nm) for films prepared by AACVD for 15 min followed by 100 "bleached"-to-colored conditioning oxidative voltammetric cycles. Electrochromic response times were <10 s and generally longer for the coloration than the bleaching process. The films showed good stability when tested for up to 10?000 color/bleach cycles. Using the CIE (Commission Internationale de l'Eclairage) system of colorimetry the color stimuli of the electrochromic NiO films and the changes that take place on reversibly oxidatively switching to the NiOOH form were calculated from in situ visible spectra recorded under electrochemical control. Reversible changes in the hue and saturation occur on oxidation of the NiO (transmissive light green) form to the NiOOH (deep brown) form, as shown by the track of the CIE 1931 xy chromaticity coordinates. As the NiO film is oxidized, a sharp decrease in luminance was observed. CIELAB L*a*b* coordinates were also used to quantify the electrochromic color states. A combination of a low L* and positive a* and b* values quantified the perceived deep brown colored state. PMID:23748903

Sialvi, Muhammad Z; Mortimer, Roger J; Wilcox, Geoffrey D; Teridi, Asri Mat; Varley, Thomas S; Wijayantha, K G Upul; Kirk, Caroline A

2013-06-26

227

Comparative chemical composition of the essential oils obtained by microwave-assisted hydrodistillation and hydrodistillation from Agrimonia pilosa LEDEB. Collected in three different regions of China.  

PubMed

Conventional hydrodistillation (HD) and microwave-assisted hydrodistillation (MAHD) were performed to obtain the volatile oils of Agrimonia pilosa Ledeb. harvested in three different regions of China, which were subsequently characterized by GC-FID and GC/MS analyses. Compared with HD, MAHD was advantageous in terms of energy savings and extraction time (60 vs. 240?min for MAHD and HD, resp.). The chemical composition varied among the different oils obtained, and the variations in the contents of the main constituents of the oils were irregular. Hence, these variations affected both the quantity and composition of the oils. The oil yields (0.15-0.21%) were affected by the method of extraction and the region of harvest, with the maximum amount of oil obtained by MAHD for the plants collected in Hubei (HB) and the minimum yield obtained by HD for the plants from Zhejing (ZJ). Hexadecanoic acid constituted the major compound of the essential oils, with the highest content found in the oil obtained by HD for plants from HB (41.18%) and the lowest one found in the oil obtained by MAHD from plants from ZJ (11.83%). Microwave irradiation did not adversely affect the composition of the essential oils. The findings show that MAHD is a modern, green, and fast technology. PMID:22422533

Wang, Hongwu; Liu, Yanqing; Wei, Shoulian; Yan, Zijun; Jin, Xing

2012-03-01

228

STUDIES ON NUCLEIC ACIDS: I. THE USE OF T4 RNA LIGASE TO JOIN CHEMICALLY SYNTHESIZED OLIGO DEOXYRIBONUCLEOTIDES. II. CHEMICAL SYNTHESIS AND PURIFICATION OF PHASING PRIMERS  

Microsoft Academic Search

Reaction conditions permitting the joining of chemically synthesized oligodeoxyribonucleotides using T4 RNA ligase have been developed. Reaction yields for the joining of a 3' ribonucleoside terminated oligodeoxyribonucleotide acceptor molecule to an oligodeoxyribonucleotide donor molecule were routinely 50-80% in 16 to 24 hours. Successful joining reactions were found to depend on the preparation of T4 RNA ligase used. The product yields

GREGORY KELLY

1983-01-01

229

Evaluated Kinetic and Photochemical Data for Atmospheric Chemistry: Supplement II. CODATA Task Group on Gas Phase Chemical Kinetics  

Microsoft Academic Search

This paper updates and extends previous critical evaluations of the kinetics and photochemistry of gas phase chemical reactions of neutral species involved in atmosphere chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11 327 (1982)]. The work has been carried out by the authors under the auspices of the CODATA Task Group on Gas Phase Chemical Kinetics. Data sheets

D. L. Baulch; R. A. Cox; R. F. Hampson; J. Troe; R. T. Watson

1984-01-01

230

Environmental chemical data for perishable sediments and soils collected in New Orleans, Louisiana, and along the Louisiana Delta following Hurricanes Katrina and Rita, 2005  

USGS Publications Warehouse

In October 2005, nearly one month after Hurricanes Katrina and Rita, a team of scientists from the U.S. Geological Survey and the Missouri University of Science and Technology deployed to southern Louisiana to collect perishable environmental data resulting from the impacts of these storms. Perishable samples collected for this investigation are subject to destruction or ruin by removal, mixing, or natural decay; therefore, collection is time-critical following the depositional event. A total of 238 samples of sediment, soil, and vegetation were collected to characterize chemical quality. For this analysis, 157 of the 238 samples were used to characterize trace element, iron, total organic carbon, pesticide, and polychlorinated biphenyl concentrations of deposited sediment and associated shallow soils. In decreasing order, the largest variability in trace element concentration was detected for lead, vanadium, chromium, copper, arsenic, cadmium, and mercury. Lead was determined to be the trace element of most concern because of the large concentrations present in the samples ranging from 4.50 to 551 milligrams per kilogram (mg/kg). Sequential extraction analysis of lead indicate that 39.1 percent of the total lead concentration in post-hurricane sediment is associated with the iron-manganese oxide fraction. This fraction is considered extremely mobile under reducing environmental conditions, thereby making lead a potential health hazard. The presence of lead in post-hurricane sediments likely is from redistribution of pre-hurricane contaminated soils and sediments from Lake Pontchartrain and the flood control canals of New Orleans. Arsenic concentrations ranged from 0.84 to 49.1 mg/kg. Although Arsenic concentrations generally were small and consistent with other research results, all samples exceeded the U.S. Environmental Protection Agency’s Human Health Medium-Specific Screening Level of 0.39 mg/kg. Mercury concentrations ranged from 0.02 to 1.30 mg/kg. Comparing the mean mercury concentration present in post-hurricane samples with regional background data from the U.S. Geological Survey National Geochemical Dataset, indicates that mercury concentrations in post-hurricane sediment generally are larger. Sequential extraction analysis of 51 samples for arsenic indicate that 54.5 percent of the total arsenic concentration is contained in the extremely mobile iron-manganese oxide fraction. Pesticide and polychlorinated biphenyl Arochlor concentrations in post-hurricane samples were small. Prometon was the most frequently detected pesticide with concentrations ranging from 2.4 to 193 micrograms per kilogram (µg/kg). Methoxychlor was present in 22 samples with a concentration ranging from 3.5 to 3,510 µg/kg. Although methoxychlor had the largest detected pesticide concentration, it was well below the U.S. Environmental Protection Agency’s High-Priority Screening Level for residential soils. Arochlor congeners were not detected for any sample above the minimum detection level of 7.9 µg/kg.

Witt, Emitt C., III; Shi, Honglan; Karstensen, Krista A.; Wang, Jianmin; Adams, Craig D.

2008-01-01

231

The chemical abundances of the stellar populations in the Leo I and II dSph galaxies  

NASA Astrophysics Data System (ADS)

We have obtained calcium abundances and radial velocities for 102 red giant branch (RGB) stars in the Leo I dwarf spheroidal galaxy (dSph) and 74 RGB stars in the Leo II dSph using the low-resolution spectrograph (LRIS) on the Keck I 10-m telescope. We report on the calcium abundances [Ca/H] derived from the strengths of the CaII triplet absorption lines at 8498, 8542 and 8662 Å in the stellar spectra using a new empirical CaII triplet calibration to [Ca/H]. The two galaxies have different average [Ca/H] values of -1.34 +/- 0.02 for Leo I and -1.65 +/- 0.02 for Leo II with intrinsic abundance dispersions of 1.2 and 1.0 dex, respectively. The typical random and total errors in derived abundances are 0.10 and 0.17 dex per star. For comparison to the existing literature, we also converted our CaII measurements to [Fe/H] on the scale of Carretta and Gratton (1997) though we discuss why this may not be the best determinant of metallicity; Leo I has a mean [Fe/H] = -1.34 and Leo II has a mean [Fe/H] = -1.59. The metallicity distribution function of Leo I is approximately Gaussian in shape with an excess at the metal-rich end, while that of Leo II shows an abrupt cut-off at the metal-rich end. The lower mean metallicity of Leo II is consistent with the fact that it has a lower luminosity, hence lower the total mass than Leo I; thus, the evolution of Leo II may have been affected more by mass lost in galactic winds. Our direct and independent measurement of the metallicity distributions in these dSph will allow a more accurate star-formation histories to be derived from future analysis of their colour-magnitude diagrams(CMDs). Data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. E-mail: tlbosler@yahoo.com

Bosler, Tammy L.; Smecker-Hane, Tammy A.; Stetson, Peter B.

2007-06-01

232

DFT calculations of 29Si-NMR chemical shifts in Ru(II) silyl complexes: searching for trends and accurate values.  

PubMed

The (29)Si chemical shifts in a series of closely related Ru(II) silyl complexes have been calculated by DFT methods and compared to the experimental values. The factors that lead to possible discrepancies between experimental and calculated values have been identified. It is shown that it is necessary to include the spin-orbit coupling associated with the relativistic effects of the heavy atoms for quantitative agreement with observed chemical shifts but trends are reasonably reproduced when the calculations do not include this correction. An NBO analysis of the NMR contributions from the bonds to Si and the Si core shows the greater importance of the former and a fine tuning originating from the latter. PMID:21975698

Poblador-Bahamonde, A I; Poteau, R; Raynaud, C; Eisenstein, O

2011-11-14

233

The population of planetary nebulae and H II regions in M 81. A study of radial metallicity gradients and chemical evolution  

NASA Astrophysics Data System (ADS)

Context. M 81 is an ideal laboratory to investigate the galactic chemical and dynamical evolution through the study of its young and old stellar populations. Aims: We analyze the chemical abundances of planetary nebulae and H ii regions in the M 81 disk for insight on galactic evolution, and compare it with that of other galaxies, including the Milky Way. Methods: We acquired Hectospec/MMT spectra of 39 PNe and 20 H ii regions, with 33 spectra viable for temperature and abundance analysis. Our PN observations represent the first PN spectra in M 81 ever published, while several H ii region spectra have been published before, although without a direct electron temperature determination. We determine elemental abundances of helium, nitrogen, oxygen, neon, sulfur, and argon in PNe and H ii regions, and determine their averages and radial gradients. Results: The average O/H ratio of PNe compared to that of the H ii regions indicates a general oxygen enrichment in M 81 in the last ~10 Gyr. The PN metallicity gradient in the disk of M 81 is ?log(O/H)/?RG = -0.055 ± 0.02 dex/kpc. Neon and sulfur in PNe have a radial distribution similar to that of oxygen, with similar gradient slopes. If we combine our H ii sample with the one in the literature we find a possible mild evolution of the gradient slope, with results consistent with gradient steepening with time. Additional spectroscopy is needed to confirm this trend. There are no type I PNe in our M 81 sample, consistently with the observation of only the brightest bins of the PNLF, the galaxy metallicity, and the evolution of post-AGB shells. Conclusions: Both the young and the old populations of M 81 disclose shallow but detectable negative radial metallicity gradient, which could be slightly steeper for the young population, thus not excluding a mild gradients steepening with the time since galaxy formation. During its evolution M 81 has been producing oxygen; its total oxygen enrichment exceeds that of other nearby galaxies. Full Tables 2 and 3 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/521/A3

Stanghellini, L.; Magrini, L.; Villaver, E.; Galli, D.

2010-10-01

234

Characterization of a 20 kHz sonoreactor. Part II: analysis of chemical effects by classical and electrochemical methods.  

PubMed

A new electrochemical redox probe has been investigated in order to characterize the local production of radicals during the cavitation events. The results have been compared with those obtained with Fe(CN)6(3-)/Fe(CN)6(4-) (electrochemical probe for local mechanical effects) and classical chemical methods such as iodide and Fricke dosimeters (chemical probes for global effects). PMID:15474954

Sáez, V; Frías-Ferrer, A; Iniesta, J; González-García, J; Aldaz, A; Riera, E

2005-01-01

235

Searching for models of thermo-chemical convection that explain probabilistic tomography. II—Influence of physical and compositional parameters  

Microsoft Academic Search

We continue the exploration of the model space of thermo-chemical convection that we started in a previous study [Deschamps, F., Tackley, P.J., 2008. Exploring the model space of thermo-chemical convection. I—Principles and influence of the rheological parameters. Phys. Earth Planet. Inter. 171, 357–373]. In this second part, we study the influence of the Rayleigh number, the internal heating, the Clapeyron

Frédéric Deschamps; Paul J. Tackley

2009-01-01

236

Preparation and use of chemically modified MCM-41 and silica gel as selective adsorbents for Hg(II) ions.  

PubMed

Adsorbents for Hg(II) ion extraction were prepared using amorphous silica gel and ordered MCM-41. Grafting with 2-(3-(2-aminoethylthio)propylthio)ethanamine was used to functionalize the silica. The functionalized adsorbents were characterized by nitrogen adsorption, X-ray diffraction, 13C MAS NMR spectroscopy and thermogravimetric analysis. The adsorption properties of the modified silica gel and MCM-41 were compared using batch method. The effect of pH, stirring time, ionic strength and foreign ions were studied. The extraction of Hg(II) ions occurred rapidly with the modified MCM-41 and the optimal pH range for the extraction by the modified materials was pH 4-7. Foreign ions, especially Cl- had some effect on the extraction efficiency of the modified silica gel and the modified MCM-41. The adsorption behavior of both adsorbents could be described by a Langmuir model at 298 K, and the maximum adsorption capacity of the modified silica gel and MCM-41 at pH 3 was 0.79 and 0.70 mmol g(-1), respectively. The modified MCM-41 showed a larger Langmuir constant than that of the modified silica gel, indicating a better ability for Hg(II) ion adsorption. The results indicate that the structure of the materials affects the adsorption behavior. These materials show a potential for the application as effective and selective adsorbents for Hg(II) removal from water. PMID:18063298

Puanngam, Mahitti; Unob, Fuangfa

2008-06-15

237

Solid phase extraction and preconcentration of Cu(II), Pb(II), and Ni(II) in environmental samples on chemically modified Amberlite XAD-4 with a proper Schiff base.  

PubMed

A new chelating resin, Amberlite XAD-4 loaded with N,N-bis(salicylidene)cyclohexanediamine (SCHD), was synthesized and characterized. The resin Amberlite XAD-4-SCHD was used for selective separation, preconcentration, and determination of Cu(II), Pb(II), and Ni(II) ions in water samples by flame atomic absorption spectrometry (FAAS). Effects of pH, concentration, and volume of elution solution; flow rate of elution; and sample solution, sample volume, and interfering ions for the recovery of the analytes were investigated. These metal ions can be desorbed with 0.5-M HNO3 (recovery, 98%-101%). The sorption capacity was found between 1.38×10(-1) and 3.58×10(-1) mmol/g. In order to evaluate the accuracy of the proposed procedure, the certified reference materials, BCR-032 (Moroccan phosphate rock) and BCR-715 (industrial effluent wastewater), were analyzed. The detection limits of the method were found to be 0.11, 1.91, and 0.43 ?g/L for Cu(II), Pb(II), and Ni(II), respectively. The method was applied to the extraction and the recovery of copper, lead, and nickel in wastewater and other water samples. PMID:20237836

Topuz, Berrin; Macit, Mustafa

2011-02-01

238

Comparison of Three Transport Systems (Starplex StarSwab II, the New Copan Vi-Pak Amies Agar Gel Collection and Transport Swabs, and BBL Port-A-Cul) for Maintenance of Anaerobic and Fastidious Aerobic Organisms  

Microsoft Academic Search

Of utmost importance in evaluations of clinical samples for infectious agents is proper specimen transport to the clinical laboratory. In the present study we compared three transport systems (the new Starplex StarSwab II, the new Copan Vi-Pak Amies Agar Gel collection and transport swabs, and the BBL Port-A-Cul) for survival of anaerobic and fastidious aerobic bacteria. The new Copan Vi-Pak

MUSA HINDIYEH; VICTORIA ACEVEDO; KAREN C. CARROLL

2001-01-01

239

Atlantic Leptolida (Hydrozoa, Cnidaria) of the families Aglaopheniidae, Halopterididae, Kirchenpaueriidae and Plumulariidae collected during the CANCAP and Mauritania-II expeditions of the National Museum of Natural History, Leiden, the Netherlands  

Microsoft Academic Search

Forty-six species of the superfamily Plumularioidea (Hydrozoa, Cnidaria) and some material identified to the generic level, collected by the CANCAP and Mauritania-II expeditions of the Rijkmuseum van Natuurlijke Historie (now Nationaal Natuurhistorisch Museum) in the period 1976-1988, are described, as well as two other species that were used in the present study. In addition to the descriptions, synonymy, variability and

J. Ansín Agís; W. Vervoort; F. Ramil

2001-01-01

240

Report on NCI symposium: comparison of mechanisms of carcinogenesis by radiation and chemical agents. II. Cellular and animal models  

SciTech Connect

The point at which the common final pathway for induction of cancer by chemical carcinogens and ionizing radiation has not been identified. Although common molecular targets are suggested by recent findings about the role of oncogenes, the mechanism by which the deposition of radiation energy and the formation of adducts or other DNA lesions induced by chemicals affects the changes in the relevant targets may be quite different. The damage to DNA that plays no part in the transformation events, but that influences the stability of the genome, and therefore, the probability of subsequent changes that influence tumorigenesis may be more readily induced by some agents than others. Similarly, the degree of cytotoxic effects that disrupt tissue integrity and increase the probability of expression of initiated cells may be dependent on the type of carcinogen. Also, evidence was presented that repair of the initial lesions could be demonstrated after exposure to low-LET radiation but not after exposure to chemical carcinogens.

Fry, R.J.M.

1984-01-01

241

Investigation of the chemical-induced selective type II (T(H)2) allergic response in mice: effect of the length of the sensitizing phase.  

PubMed

Allergies are immune system disorders characterized by abnormal, acquired sensitivity to various environmental chemicals. We investigated the mechanism of chemical-induced selective type II (T(H)2) allergy by using three different sensitization protocols and the well-known respiratory sensitizer trimellitic anhydride (TMA). Mice were sensitized for either 1, 2, or 3 weeks. For each sensitization schedule, the mice were allocated into 3 or 4 groups: -/- group, both sensitized and challenged with vehicle; -/+ group, sensitized with vehicle and challenged with 0.1% TMA; +/- group, sensitized with 1% TMA and challenged with vehicle; and +/+ group, both sensitized and challenged with 0.1% TMA. After challenge, we assayed the auricular lymph nodes of all mice for number of lymphocytes, surface antigen expression of B-cells, and local cytokine production, and we measured TMA-specific serum IgE levels. Some parameters in mice sensitized for 1 or 2 wk showed, at most, mild changes. In contrast, all parameters in animals receiving 3-wk sensitization showed marked increases, as well as marked increases in the IgE/major histocompatibility complex (MHC) Class II-positive B-cell population and T(H)2 cell production of IL-10 and IL-13. These results indicate that 3 wk of sensitization according to our protocol led to overt respiratory allergic reactions. While these studies showed that using the approach here, positive reactions were elicited using a typical allergen; whether the same events occur after sensitization by other chemicals that are found in the environment remains uncertain. These findings here should be regarded moreover as preliminary in scope and that additional studies with irritants, dermal sensitizers and other respiratory sensitizers are needed to further evaluate the overall sensitivity and selectivity of this novel protocol. PMID:19589094

Fukuyama, Tomoki; Tajima, Yukari; Ueda, Hideo; Hayashi, Koichi; Shutoh, Yasufumi; Saito, Toru R; Harada, Takanori; Kosaka, Tadashi

2009-06-01

242

Searching for models of thermo-chemical convection that explain probabilistic tomography. II—Influence of physical and compositional parameters  

NASA Astrophysics Data System (ADS)

We continue the exploration of the model space of thermo-chemical convection that we started in a previous study [Deschamps, F., Tackley, P.J., 2008. Exploring the model space of thermo-chemical convection. I—Principles and influence of the rheological parameters. Phys. Earth Planet. Inter. 171, 357-373]. In this second part, we study the influence of the Rayleigh number, the internal heating, the Clapeyron slope of the 660-km transition, the chemical density contrast between dense and regular materials (buoyancy ratio), and the volume fraction of dense material. We apply the same analysis and test the chemical and thermal density distributions predicted by various thermo-chemical models against those predicted by probabilistic tomography. Varying the reference Rayleigh number within a reasonable range of values for the Earth's mantle, we find significant differences in the flow pattern and efficiency of mixing. A Rayleigh number equal to 1/3 only of the standard value (10 8) helps to maintain compositional anomalies throughout the system during a long period of time. The internal heating has no or very little influence on the flow pattern and the efficiency of mixing. An endothermic phase transition with a (non-)dimensional Clapeyron slope lower than -1.0 MPa/K strongly inhibits the mass exchange and thus the efficiency of mixing. It provides a convenient way to maintain strong compositional anomalies in the lower mantle during a long period of time. The stability of the layer of dense material is mainly controlled by the buoyancy ratio, and the influence of the volume fraction of dense material is only of second order. These experiments, together with those performed in our previous study, suggest that four ingredients may enter a successful thermo-chemical model of convection for the Earth's mantle: (1) A buoyancy ratio between 0.15 and 0.25, which is equivalent to a chemical density contrast in the range 90-150 kg/m 3; (2) a large (?10 4), thermal viscosity contrast, which creates and maintains pools of dense material at the bottom of the mantle; (3) a viscosity contrast at d = 660 km around 30; and (4) a Clapeyron slope of the phase transition at d = 660 km of about -3.0 to -1.5 MPa/K. In addition, pools of dense material can be generated and maintained for a large range of values of the chemical viscosity contrast, but the detailed structure of the pools significantly depends on this parameter.

Deschamps, Frédéric; Tackley, Paul J.

2009-09-01

243

Analysis of management actions, human behavior, and process reliability in chemical plants. II. Near-miss management system selection  

Microsoft Academic Search

ABSTRACT Tounderstand the behavior patterns of managers, engineers, and operators, in Part II, a game-theoretic decision model isdeveloped,for a specific plant to balance the advantages and disadvantages of having ,a Near-miss Management ,System (NMMS) with different sophistication levels. Assuming ,that management ,and engineering preferences differ from those of the process operators, the tradeoffs between them are balanced. As anticipated, it

Anjana Meel; Warren D. Seider; Ulku Oktem

2008-01-01

244

Soft chemicals synthesis of a high-pressure phase of molybdenum trioxide: MoO{sub 3}-II  

SciTech Connect

Topotactic dehydration of either the white molybdenum trioxide monohydrate, MoO{sub 3}{center_dot}H{sub 2}O, or the hemihydrate MoO{sub 3}{center_dot}{1/2}H{sub 2}O, provides a convenient synthetic route to a high-pressure phase of molybdenum trioxide, MoO{sub 3-}II. The structural filiations between the various molybdenum trioxide hydrates phases are delineated, and simple mechanistic models for the transformations are proposed.

Baker, B.; Feist, T.P.; McCarron, E.M. [DuPont Company, Wilmington, DE (United States)] [DuPont Company, Wilmington, DE (United States)

1995-10-01

245

Assessment of reproductive disorders and birth defects in communities near hazardous chemical sites. II. Female reproductive disorders.  

PubMed

Members of the workgroup on female reproductive disorders discussed methods to evaluate five principal functions: menstrual dysfunction, infertility, pregnancy loss, lactation disorders, and pregnancy complications. To test each function, a nested strategy was considered, based on progressive levels of effort available to conduct field investigations. This strategy was analogous to the three-tier classification of biomarkers used by other workshops. The lowest level of effort, corresponding to Tier 1, consists only of questionnaires, diaries, and reviews of maternal and infant medical records. The medium level of effort (Tier 2) collects data from questionnaires and diaries, and some biologic specimens. Suggested laboratory analyses included measurement of progesterone in saliva and several glycoprotein hormones in urine that evaluate menstrual dysfunction, infertility, and pregnancy loss. The highest level of effort (Tier 3) involves prospective collection of diary information and simultaneous collection of biological specimens. PMID:9100298

Scialli, A R; Swan, S H; Amler, R W; Baird, D D; Eskenazi, B; Gist, G; Hatch, M C; Kesner, J S; Lemasters, G K; Marcus, M; Paul, M E; Schulte, P; Taylor, Z; Wilcox, A J; Zahniser, C

1997-01-01

246

Toxicology studies of a chemical mixture of 25 groundwater contaminants. II. Immunosuppression in B6C3F1 mice  

SciTech Connect

Concern over the potential adverse health effects of chemically contaminated groundwater has existed for many years. In general, these studies have focused on retrospective epidemiological studies for cancer risk. In the present studies, immune function was monitored in female B6C3F1 mice exposed to a chemical mixture in drinking water for either 14 or 90 days. The mixture consisted of 25 common groundwater contaminants frequently found near toxic waste dumps, as determined by EPA surveys. None of the animals developed overt signs of toxicity such as body or liver weight changes. Mice exposed to the highest dose of this mixture for 14 or 90 days showed immune function changes which could be related to rapidly proliferating cells, including suppression of hematopoietic stem cells and of antigen-induced antibody-forming cells. Some of these responses, e.g., granulocyte-macrophage colony formation, were also suppressed at lower concentrations of the chemical mixture. There were no effects on T cell function or T and B cell numbers in any of the treatment groups. Altered resistance to challenge with an infectious agent also occurred in mice given the highest concentration, which correlated with the immune function changes. Paired-water studies indicated that the immune effects were related to chemical exposure and not to decreased water intake. These results suggest that long-term exposure to contaminated groundwater may represent a risk to the immune system in humans.

Germolec, D.R.; Yang, R.S.; Ackermann, M.F.; Rosenthal, G.J.; Boorman, G.A.; Blair, P.; Luster, M.I. (National Institutes of Environmental Health Sciences, Research Triangle Park, NC (USA))

1989-10-01

247

Amphibians as a model to study endocrine disruptors: II. Estrogenic activity of environmental chemicals in vitro and in vivo  

Microsoft Academic Search

Several environmental chemicals are known to have estrogenic activity by interacting with development and functions of endocrine systems in nearly all classes of vertebrates. In order to get a better insight of potential estrogenic effects on amphibians caused by environmental pollution this study aims to develop a model for investigating endocrine disruptors using the amphibian Xenopus laevis. In that model

Werner Kloas; Ilka Lutz; Ralf Einspanier

1999-01-01

248

Eutrophication of the salt valley reservoirs, 1968–1973 II. Changes in physical and chemical parameters of eutrophication  

Microsoft Academic Search

This study, conducted over a six-year period in four relatively new flood control reservoirs where large increases in phytoplankton populations and alterations in their composition indicated rapid eutrophication, examined the concurrent changes in physical and chemical parameters used by other investigators to document eutrophication in lakes, and evaluates their usefulness as indicators of eutrophication in small, shallow, holomictic reservoirs. Several

Gary L. Hergenrader

1980-01-01

249

Fast Analysis Conditions for Chemical Warfare Agents: Providing the Environmental Protection Agency with Ultra-Dilute Chemical Warfare Agent Standards. Part II: Procedure for Purity Determination of Chemical Warfare Agent (CWA) Standards.  

National Technical Information Service (NTIS)

This document describes procedures used to assure the quality of ultradilute (10 part-permillion) chemical warfare agent (CWA) standards provided to the United States Environmental Protection Agency (EPA) Environmental Response Laboratory Network (ERLN) l...

H. Mulcahy

2011-01-01

250

Chemical preparation of conductive elastomeric blends: polypyrrole\\/EPDM—II. Utilization of matrices containing crosslinking agents, reinforcement fillers and stabilizers  

Microsoft Academic Search

Semi-interpenetrating networks (semi-IPN) of polypyrrole and ethylene-propylene-5-ethylidene-2-norbornene rubber, EPDM, were prepared by chemical oxidation of the monomer using two different methods of synthesis. In the first method, EPDM rubber samples containing CuCl2 (powder with granulometry < 105 ?m) and dicumyl peroxide were obtained by mechanical mixing, crosslinked by heating and exposed to pyrrole vapours. In the second route, EPDM rubber

R. A. Zoppi; Marco-A. De Paoli

1996-01-01

251

75 FR 35021 - Agency Information Collection Activities; Proposed Collection; Comment Request; Information...  

Federal Register 2010, 2011, 2012, 2013

...Request; Information Collection Request for Cooling Water Intake Structure Phase II Existing...Title: Information Collection Request for Cooling Water Intake Structure Phase II Existing...another entity for transmission, use a cooling water intake structure (CWIS) that...

2010-06-21

252

Inplementation of an automated signal processing approach for the analysis of chemical spectral signatures collected from FT-IR mounted in an aircraft  

SciTech Connect

The automated detection of chemical spectral signatures using a passive infrared Fourier Transform Infrared (FT-IR) Spectrometer mounted in an aircraft is a difficult challenge due to the small total infrared energy contribution of a particular chemical species compared to the background signature. The detection of spectral signatures is complicated by the fact that a large, widely varying infrared background is present that is coupled with the presence of a number of chemical interferents in the atmosphere. This paper describes a mathematical technique that has been demonstrated to automatically detect specific chemical species in an automated processing environment. The data analysis methodology has been demonstrated to be effective using data of low spectral resolution at low aircraft altitudes. An overview of the implementation and basic concepts of the approach are presented.

Kroutil, Robert T [Los Alamos National Laboratory

2008-01-01

253

Metalorganic chemical vapor deposition growth of InAs/GaSb type II superlattices with controllable AsxSb1-x interfaces  

PubMed Central

InAs/GaSb type II superlattices were grown on (100) GaSb substrates by metalorganic chemical vapor deposition (MOCVD). A plane of mixed As and Sb atoms connecting the InAs and GaSb layers was introduced to compensate the tensile strain created by the InAs layer in the SL. Characterizations of the samples by atomic force microscopy and high-resolution X-ray diffraction demonstrate flat surface morphology and good crystalline quality. The lattice mismatch of approximately 0.18% between the SL and GaSb substrate is small compared to the MOCVD-grown supperlattice samples reported to date in the literature. Considerable optical absorption in 2- to 8-?m infrared region has been realized. PACS: 78.67.Pt; 81.15.Gh; 63.22.Np; 81.05.Ea

2012-01-01

254

DNAPL remediation with in situ chemical oxidation using potassium permanganate. II. Increasing removal efficiency by dissolving Mn oxide precipitates.  

PubMed

In situ chemical oxidation (ISCO) schemes using MnO4- have been effective in destroying chlorinated organic solvents dissolved in ground water. Laboratory experiments and field pilot tests reveal that the precipitation of Mn oxide, one of the reaction products, causes a reduction of permeability, which can lead to flow bypassing and inefficiency of the scheme. Without a solution to this problem of plugging, it is difficult to remove DNAPL from the subsurface completely. In a companion paper, we showed with batch experiments that Mn oxide can be dissolved rapidly with certain organic acids. This study utilizes 2-D flow-tank experiments to examine the possibility of nearly complete DNAPL removal by ISCO with MnO4-, when organic acids are used to remove Mn oxide. The experiments were conducted in a small 2-D glass flow tank containing a lenticular silica-sand medium. Blue-dyed trichloroethylene (TCE) provided residual, the perched and pooled DNAPL. KMnO4 at 200 mg/l was flushed through the DNAPL horizontally. Once plugging reduced permeability and prevented further delivery of the oxidant, citric or oxalic acids were pumped into the flow tank to dissolve the Mn oxide precipitates. Organic ligands removed the Mn oxide precipitates relatively quickly, and permitted another cycle of MnO4- flooding. Cycles of MnO4-/acid flooding continued until all of the visible DNAPL was removed. The experiments were monitored with chemical analysis and visualization. A mass-balance calculation indicated that by the end of the experiments, all the DNAPL was removed. The results show also how heterogeneity adds complexity to initial redistribution of DNAPL, and to the efficiency of the chemical flooding. PMID:14734249

Li, X David; Schwartz, Franklin W

2004-02-01

255

DNAPL remediation with in situ chemical oxidation using potassium permanganate - II. Increasing removal efficiency by dissolving Mn oxide precipitates  

NASA Astrophysics Data System (ADS)

In situ chemical oxidation (ISCO) schemes using MnO 4- have been effective in destroying chlorinated organic solvents dissolved in ground water. Laboratory experiments and field pilot tests reveal that the precipitation of Mn oxide, one of the reaction products, causes a reduction of permeability, which can lead to flow bypassing and inefficiency of the scheme. Without a solution to this problem of plugging, it is difficult to remove DNAPL from the subsurface completely. In a companion paper, we showed with batch experiments that Mn oxide can be dissolved rapidly with certain organic acids. This study utilizes 2-D flow-tank experiments to examine the possibility of nearly complete DNAPL removal by ISCO with MnO 4-, when organic acids are used to remove Mn oxide. The experiments were conducted in a small 2-D glass flow tank containing a lenticular silica-sand medium. Blue-dyed trichloroethylene (TCE) provided residual, the perched and pooled DNAPL. KMnO 4 at 200 mg/l was flushed through the DNAPL horizontally. Once plugging reduced permeability and prevented further delivery of the oxidant, citric or oxalic acids were pumped into the flow tank to dissolve the Mn oxide precipitates. Organic ligands removed the Mn oxide precipitates relatively quickly, and permitted another cycle of MnO 4- flooding. Cycles of MnO 4-/acid flooding continued until all of the visible DNAPL was removed. The experiments were monitored with chemical analysis and visualization. A mass-balance calculation indicated that by the end of the experiments, all the DNAPL was removed. The results show also how heterogeneity adds complexity to initial redistribution of DNAPL, and to the efficiency of the chemical flooding.

Li, X. David; Schwartz, Franklin W.

2004-02-01

256

Theoretical description of copper Cu(I)/Cu(II) complexes in mixed ammine-aqua environment. DFT and ab initio quantum chemical study  

NASA Astrophysics Data System (ADS)

This work is devoted to investigate the interactions of the Cu(I)/Cu(II) cation with variable ammonia-water ligand field by the quantum chemical approach. For that purpose, the optimization of the [Cu(NH 3) m(H 2O) n] 2+/+ complexes (where n varies from 0 to 4 or 6 and m + n = 4 or 6) has been performed at the DFT/6-31+G(d) level of theory in conjunction with the B3PW91 hybrid functional. Based on the results of the single-point B3LYP/6-311++G(2df,2pd) calculations, the stabilization energies were determined. The two-coordinated copper(I) complexes appeared to be the most stable compounds with the remaining water or ammonia molecules in the second solvation shell. In the case of the Cu(II) systems, four-coordinated complexes were found to be the most stable. In order to examine and explain bonding characteristics, Morokuma interaction energy decomposition (for selected Cu + complexes) and Natural Population Analysis for all systems were performed. It was found that the most stable structures correlate with the highest donation effects. Therefore, more polarizable ammonia molecules exhibit higher donation than water and thus make stronger bonds to copper. This can be demonstrated by the fact that the NH 3 molecule always tries to occupy the first solvation shell in mixed ammine-aqua complexes.

Pavelka, Mat?j; Burda, Jaroslav V.

2005-06-01

257

Chemical oscillators in group VIA: the Cu(II)-catalyzed reaction between hydrogen peroxide and thiosulfate ion  

SciTech Connect

In the presence of small amounts (approx. 10/sup -5/ M) of Cu(II), the reaction between hydrogen peroxide and thiosulfate ion in a stirred tank reactor exhibits one oscillatory and three stationary states as well as bistability between the oscillatory and one of the stationary states and between two stationary states. The amplitude of the oscillations can be as large as 4 pH units or 200 mV in the potential of a Pt redox electrode. Near the bistable regions, the system undergoes large over- and undershoots as the flow rate is varied. In the absence of the copper catalyst, only a single steady state is found, with no unusual dynamical phenomena. Some tentative mechanistic suggestions are offered to account for this behavior.

Orban, M.; Epstein, I.R.

1987-01-07

258

Historical estimates of external gamma exposure and collective external gamma exposure from testing at the Nevada Test Site. I. Test series through HARDTACK II, 1958  

SciTech Connect

In 1959, the Test Manager's Committee to Establish Fallout Doses calculated estimated external gamma exposure at populated locations based upon measurements of external gamma-exposure rate. Using these calculations and estimates of population, we have tabulated the collective estimated external gamma exposures for communities within established fallout patterns. The total collective estimated external gamma exposure is 85,000 person-R. The greatest collective exposures occurred in three general areas: Saint George, UT; Ely, NV; and Las Vegas, NV. Three events, HARRY (19 May 1953), BEE (22 March 1955), and SMOKY (31 August 1957), accounted for more than half the total collective estimated external gamma exposure. The bases of the calculational models for external gamma exposure of infinite exposure, estimated exposure, and 1-yr effective biological exposure are explained.

Anspaugh, L.R.; Church, B.W.

1986-07-01

259

Historical estimates of external gamma exposure and collective external gamma exposure from testing at the Nevada Test Site. I. Test series through HARDTACK II, 1958.  

PubMed

In 1959, the Test Manager's Committee to Establish Fallout Doses calculated estimated external gamma exposure at populated locations based upon measurements of external gamma-exposure rate. Using these calculations and estimates of population, we have tabulated the collective estimated external gamma exposures for communities within established fallout patterns. The total collective estimated external gamma exposure is 85,000 person-R. The greatest collective exposures occurred in three general areas: Saint George, UT; Ely, NV; and Las Vegas, NV. Three events, HARRY (19 May 1953), BEE (22 March 1955), and SMOKY (31 August 1957), accounted for more than half the total collective estimated external gamma exposure. The bases of the calculational models for external gamma exposure of "infinite exposure," "estimated exposure," and "1-yr effective biological exposure" are explained. PMID:3332000

Anspaugh, L R; Church, B W

1986-07-01

260

Historical estimates of external gamma exposure and collective external gamma exposure from testing at the Nevada Test Site. I. Test series through HARDTACK II, 1958  

SciTech Connect

In 1959, the Test Manager's Committee to Establish Fallout Doses calculated estimated external gamma exposure at populated locations based upon measurements of external gamma-exposure rate. Using these calculations and estimates of population, we have tabulated the collective estimated external gamma exposures for communities within established fallout patterns. The total collective estimated external gamma exposure is 85,000 person-R. The greatest collective exposures occurred in three general areas: Saint George, Utah; Ely, Nevada; and Las Vegas, Nevada. Three events, HARRY (May 19, 1953), BEE (March 22, 1955), and SMOKY (August 31, 1957), accounted for over half of the total collective estimated external gamma exposure. The bases of the calculational models for external gamma exposure of ''infinite exposure,'' ''estimated exposure,'' and ''one year effective biological exposure'' are explained. 4 figs., 7 tabs.

Anspaugh, L.R.; Church, B.W.

1985-12-01

261

Analysis of the Armature-Rail Interface in Solid Armature Railguns: Collected Reports of Professor L. C. Woods Volume II (November 1996 - May 1997).  

National Technical Information Service (NTIS)

A second collection of reports written by L.C. Woods for the Institute for Advanced Technology (IAT), University of Texas at Austin, investigating the liquid metal interface between a solid armature and conducting rail of an electromagnetic launcher. The ...

L. C. Woods

1997-01-01

262

Science Research Annual, Volume II: A Collection of Science Staff Memoranda and Letters from the Illinois Legislature Council - January-June 1980.  

National Technical Information Service (NTIS)

This volume contains a collection of correspondence and contributions from the Illinois Legislative Council. The memoranda, which have been organized into research reports, answer requests from individual legislators for information on specific science, t...

J. A. Dutton

1981-01-01

263

Single particle chemical composition, state of mixing and shape of fresh and aged Saharan dust in Morocco and at Cape Verde Islands during SAMUM I and II  

NASA Astrophysics Data System (ADS)

The Saharan Mineral Dust Experiment (SAMUM) is focussed to the understanding of the radiative effects of mineral dust. During the SAMUM 2006 field campaign at Tinfou, southern Morocco, chemical and mineralogical properties of fresh desert aerosol was measured. The winter campaign of Saharan Mineral Dust Experiment II in 2008 was based in Praia, Island of Santiago, Cape Verde. This second field campaign was dedicated to the investigation of transported Saharan Mineral Dust. Ground-based and airborne measurements were performed in the winter season, where mineral dust from the Western Sahara and biomass burning aerosol from the Sahel region occurred. Samples were collected with a miniature impactor system, a sedimentation trap, a free-wing impactor, and a filter sampler. Beryllium discs as well as carbon coated nickel discs, carbon foils, and nuclepore and fiber filters were used as sampling substrates. The size-resolved particle aspect ratio and the chemical composition are determined by scanning electron microscopy and energy-dispersive X-ray microanalysis of single particles. Mineralogical bulk composition is determined by X-ray diffraction analysis. In Morocco, three size regimes are identified in the aerosol: Smaller than 500 nm in diameter, the aerosol consists of sulfates and mineral dust. Larger than 500 nm up to 50 µm, mineral dust dominates, consisting mainly of silicates, and - to a lesser extent - carbonates and quartz. Larger than 50 µm, approximately half of the particles consist of quartz. Time series of the elemental composition show a moderate temporal variability of the major compounds. Calcium-dominated particles are enhanced during advection from a prominent dust source in Northern Africa (Chott El Djerid and surroundings). More detailed results are found in Kandler et al. (2009) At Praia, Cape Verde, the boundary layer aerosol consists of a superposition of mineral dust, marine aerosol and ammonium sulfate, soot, and other sulfates as well as mixtures of these components. During low-dust periods, the aerosol is dominated by sea salt. During dust events, mineral dust dominates the particle mass (more than 90 %). Particles smaller 500 nm in diameter always show a significant abundance of ammonium sulfate. Comparing a high dust period at Cape Verde with the total data from Morocco, it is found that the atomic ratio distributions of Al/Si, K/Si and Fe/Si for the single particles are very similar for the dust component. This indicates that the dominating silicate minerals are the same. In contrast, the content of calcium rich minerals at Cape Verde is significantly lower than in Morocco which is in agreement with the source regions for the Cape Verde dust (E Mali and W Niger) derived from trajectory analysis. The sulfur content of super-micron aerosol particles at Cape Verde scales with the particle surface, indicating the presence of sulfate coatings. For the submicron particles, the sulfur content scales with particle volume, which can be attributed to the large amount of particles identified as ammonium sulfate. In contrast to findings in Japan (Zhang et al., 2006), no internal mixtures between pristine seasalt and mineral dust are present during this dust period at Cape Verde. However, for a significant number of particles a small amount of sodium and chlorine is associated with internal mixtures of dust and sulfate, what may indicate that these particles started as internal mixture of dust with a sea water droplet before taking up more sulfur from the gas phase. In general, the shape of the particles in Morocco and Cape Verde is rather similar: The distributions of the two-dimensional aspect ratio of an ellipse fitted to each particle's shape for the total aerosol show no significant differences. A median value of 1.6 is found for both locations. References Kandler, K., Schütz, L., Deutscher, C., Hofmann, H., Jäckel, S. and co-authors 2009. Tellus 61B, 32-50. Zhang, D., Iwasaka, Y., Matsuki, A., Ueno, K. and Matsuzaki, T. 2006. Atmos. Environ. 40, 1205-1215. Financial support by the Deutsche Forsch

Kandler, Konrad; Emmel, Carmen; Ebert, Martin; Lieke, Kirsten; Müller-Ebert, Dörthe; Schütz, Lothar; Weinbruch, Stephan

2010-05-01

264

Part I. Synthesis of metal hydroborates as potential chemical vapor deposition precursors. Part II. Chemical vapor deposition of titanium-doped magnesium diboride thin films  

NASA Astrophysics Data System (ADS)

New compounds Cp*V(B3H8)2, Cp*Cr(B 3H8)2, and Cp*2Co2(B 6H14) have been synthesized by treating the pentamethylcyclopentadienyl complexes [Cp*VCl2]3, [Cp*CrCl2]2, and [Cp*CoCl]2 with NaB3H8. Cp*V(B3 H8)2 and Cp*Cr(B3H8) 2 have the same ligand sets but different molecular structures: the vanadium compound contains two bidentate B3H8 ligands whereas the chromium compound has one bidentate B3H8 ligand and one B3H8 ligand bound in an unprecedented fashion via two geminal hydrogen atoms. The different binding modes of the B3H8- group in these compounds are consequences of the number of available empty valence orbitals on the metal centers. The dinuclear complex Cp*2Co2(B 6H14) can be viewed as a "bi-borallyl" complex or as an eight-vertex hypho cluster. The solid state reaction of MgBr2 and NaB3H 8 at 20°C, followed by sublimation at 80°C and 0.05 Torr, affords Mg(B3H8)2, as a white solid. Similar reactions with MgBr2·Et2O and MgBr2(Me 2O)1.5 afford the crystalline ether adducts Mg(B3H 8)2(Et2O)2 and Mg(B3H 8)2(Me2O)2, respectively. In the solution state reactions of MgBr2 with NaB3H8, the presence of excess solvent results in the formation of non-volatile, probably ionic, magnesium compounds of the type [MgLx][B3H 8]2. Mg(B3H8)2(Et2 O)2 and Mg(B3H8)2(Me 2O)2 are the first crystallographically characterized magnesium complex of the B3H8- ligand. Owing to their volatility, Mg(B3H8)2(Et2O) 2 and Mg(B3H8)2(Me2O) 2 are potential precursors for the deposition of MgB2 thin films, although preliminary efforts to grow thin films from them under CVD conditions, have not yet produced stoichiometric MgB2 films. Treatment of MCl3(thf)3 (M = Ti, Cr, or Mo) or MnCl2 with the sodium salt of N,N-dimethyldiboranamide, Na(H3BNMe2BH3), in diethyl ether, followed by sublimation at 45-70°C, affords crystals of the new divalent complexes M(H3BNMe2BH3)2, where M is Ti, Cr, Mn, or Mo, all of which have been characterized by single crystal X-ray diffraction. In all four compounds, the metal center is coordinated to two chelating [H3BNMe2BH3]-ligands. Each BH3 group binds to the metal center by means of two hydrogen bridges, leaving one terminal hydrogen atom on each BH3 group; the H atoms that bridge to the metal center form slightly longer B-H bonds than the terminal H atoms on the same boron centers, as expected. The metal center in each compound forms eight M-H contacts, whose M-H distances are equal within experimental error. The Ti, Cr, and Mo compounds adopt square-planar geometries in which the dihedral angle between ligand planes is 0°. In contrast, in the Mn compound, which adopts a structure intermediate between a tetrahedron and a square plane, the two ligand planes define a dihedral angle of 46.5(2)°; this unusual dihedral angle maximizes interligand H···H distances. The solid state reaction of MgBr2 with Na(H3BNMe 2BH3) yields the monomeric, magnesium complex Mg(H3 BNMe2BH3)2. Its ether adducts Mg(H 3BNMe2BH3)2(thf) and Mg(H3BNMe 2BH3)2(dme), and the mixed ligand complex Cp*Mg(H 3BNMe2BH3)(thf), have also been prepared. Significantly, the binary complex Mg(H3BNMe2BH3)2 has a vapor pressure of 800 mTorr at 25°C, which makes it the most volatile magnesium complex known. The solid state reaction of MCl3 and Na(H3BNMe 2BH3) and subsequent sublimation in vacuum affords the dinuclear complexes, M2(H3BNMe2BH3) 6 (M = Y or Dy). X-ray crystallographic studies show that, in both compounds, two metal centers are connected by two bridging H3BNMe2BH 3 ligands; each metal center also bears two terminal diboranamide groups, which are chelating. Similar reactions conducted in thf solution yield the monomeric thf adducts M(H3BNMe2BH3) 3(thf) (M = Y or Dy). These molecules, which possess a boron-to-metal ratio of 6, are readily volatile below 100°C and are potential CVD precursors for the low-temperature growth of LnB6 thin films. The first low-temperature chemical vapor depositions of doped MgB 2 phases have been achieved by passing the precursor Mg(H3BNMe 2BH3)2 over a surface in the presence of a catalyst that accelerates the rate

Kim, Do Young

265

Computer programming for nucleic acid studies. II. Total chemical shifts calculation of all protons of double-stranded helices.  

PubMed

A FORTRAN computer program called SHIFTS is described. Through SHIFTS, one can calculate the NMR chemical shifts of the proton resonances of single and double-stranded nucleic acids of known sequences and of predetermined conformations. The program can handle RNA and DNA for an arbitrary sequence of a set of 4 out of the 6 base types A,U,G,C,I and T. Data files for the geometrical parameters are available for A-, A'-, B-, D- and S-conformations. The positions of all the atoms are calculated using a modified version of the SEQ program [1]. Then, based on this defined geometry three chemical shift effects exerted by the atoms of the neighboring nucleotides on the protons of each monomeric unit are calculated separately: the ring current shielding effect: the local atomic magnetic susceptibility effect (including both diamagnetic and paramagnetic terms); and the polarization or electric field effect. Results of the program are compared with experimental results for a gamma (ApApGpCpUpU) 2 helical duplex and with calculated results on this same helix based on model building of A'-form and B-form and on graphical procedure for evaluating the ring current effects. PMID:6274583

Giessner-Prettre, C; Ribas Prado, F; Pullman, B; Kan, L; Kast, J R; Ts'o, P O

1981-01-01

266

Critical evaluation of Jet-A spray combustion using propane chemical kinetics in gas turbine combustion simulated by KIVA-II  

NASA Technical Reports Server (NTRS)

Numerical solutions of the Jet-A spray combustion were obtained by means of the KIVA-II computer code after Jet-A properties were added to the 12 chemical species the program had initially contained. Three different reaction mechanism models are considered. The first model consists of 131 reactions and 45 species; it is evaluated by comparing calculated ignition delay times with available shock tube data, and it is used in the evaluation of the other two simplified models. The simplified mechanisms consider 45 reactions and 27 species and 5 reactions and 12 species, respectively. In the prediction of pollutants NOx and CO, the full mechanism of 131 reactions is considered to be more reliable. The numerical results indicate that the variation of the maximum flame temperature is within 20 percent as compared with that of the full mechanism of 131 reactions. The chemical compositions of major components such as C3H8, H2O, O2, CO2, and N2 are of the same order of magnitude. However, the concentrations of pollutants are quite different.

Nguyen, H. L.; Ying, S.-J.

1990-01-01

267

Chemical modification of N6-(N-threonylcarbonyl) adenosine. Part II. Condensation of the carboxyl group with amines.  

PubMed

Carboxyl group of N6-/N-threonylcarbonyl/adenosine was quantitatively modified with amines/aniline, glycine ethyl ester and ethylenediamine/in the presence of a water-soluble carbodiimide, yielding the respective amides. The reaction was carried out in a water solution of pH about 4 at 20 degrees C and was finished within minutes. The structure of the products was confirmed by UV and PMR spectra, and by chemical reactivity. Under conditions applied for modification of T6A, four common nucleosides and internucleotide linkage of UpA were unreactive, while 5'-AMP was transformed to the respective phosphoramides. At pH 4, the rate of 5'-AMP modification was over 100 times lower than the rate of t6A reaction. PMID:503865

Krzyzosiak, W J; Biernat, J; Ciesio?ka, J; Górnicki, P; Wiewiórowski, M

1979-11-24

268

Trapping of muscle relaxant methocarbamol degradation product by complexation with copper(II) ion: spectroscopic and quantum chemical studies.  

PubMed

Structural properties of methocarbamol (Mcm) were extensively studied both experimentally and theoretically using FT IR, (1)H NMR, UV-Vis., geometry optimization, Mulliken charge, and molecular electrostatic potential. Stability arises from hyper-conjugative interactions, charge delocalization and H-bonding was analyzed using natural bond orbital (NBO) analysis. Mcm was decomposed in ethanol/water mixture at 80°C to guaifenesin [(RS)-3-(2-methoxyphenoxy)propane-1,2-diol] and carbamate ion [NH2COO(-)], where the degradation mechanism was explained by trapping the carbamate ion via the complexation with copper(II) ion. The structure of the isolated complex ([Cu(NH2COO)2(H2O)]?4H2O) was elucidated by spectral, thermal, and magnetic tools. Electronic spectra were discussed by TD-DFT and the descriptions of frontier molecular orbitals and the relocations of the electron density were determined. Calculated g-tensor values showed best agreement with experimental values from EPR when carried out using both the B3LYP and B3PW91 functional. PMID:24674917

Mansour, Ahmed M; Shehab, Ola R

2014-07-15

269

Chemical relevance of the copper(II)— L-carnosine system in aqueous solution: A thermodynamic and spectrophotometric study  

NASA Astrophysics Data System (ADS)

The copper(II)— L-carnosine (L -) system has been re-investigated in aqueous solution, at I = 0.1 mol dm -1, different temperatures (5? t?45°C) and with metal to ligand ratios ranging from 3:1 to 1:3. Both potentiometry and visible spectrophotometry were employed. From an overall consideration of all experiments, [CuLH] 2+, [CuL] +, [CuLH -1]°, [Cu 2L 2H -2]° and [Cu 2LH -1] 2+ were recognized as the species which provide the best interpretation of experimental data. The complex formation constants, determined at different temperatures, allowed us to obtain reliable values of ? H° and good estimates of ? C° p. From visible spectrophotometric measurements, carried out at different pH and metal to ligand ratios, it was possible to calculate the electronic spectrum of each complex formed in solution. A structure is also proposed for each species, on the basis of thermodynamic and spectral results.

Daniele, Pier G.; Prenesti, Enrico; Zelano, Vincenzo; Ostacoli, Giorgio

1993-08-01

270

On Ammonia Binding to the Oxygen-Evolving Complex of Photosystem?II: A Quantum Chemical Study.  

PubMed

A recent EPR study (M. Perrez Navarro et?al., Proc. Natl. Acad. Sci.- 2013, 110, 15561) provided evidence that ammonia binding to the oxygen-evolving complex (OEC) of photosystem?II in its S2 state takes place at a terminal-water binding position (W1) on the "dangler" manganese center MnA . This contradicted earlier interpretations of (14) N electron-spin-echo envelope modulation (ESEEM) and extended X-ray absorption fine-structure (EXAFS) data, which were taken to indicate replacement of a bridging oxo ligand by an NH2 unit. Here we have used systematic broken-symmetry density functional theory calculations on large (ca. 200 atom) model clusters of an extensive variety of substitution patterns and core geometries to examine these contradictory pieces of evidence. Computed relative energies clearly favor the terminal substitution pattern over bridging-ligand arrangements (by about 20-30?kcal?mol(-1) ) and support W1 as the preferred binding site. Computed (14) N EPR nuclear-quadrupole coupling tensors confirm previous assumptions that the appreciable asymmetry may be accounted for by strong, asymmetric hydrogen bonding to the bound terminal NH3 ligand (mainly by Asp61). Indeed, bridging NH2 substitution would lead to exaggerated asymmetries. Although our computed structures confirm that the reported elongation of an Mn-Mn distance by about 0.15?Å inferred from EXAFS experiments may only be reproduced by bridging NH2 substitution, it seems possible that the underlying EXAFS data were skewed by problems due to radiation damage. Overall, the present data clearly support the suggested terminal NH3 coordination at the W1 site. The finding is significant for the proposed mechanistic scenarios of OEC catalysis, as this is not a water substrate site, and effects of this ammonia binding on catalysis thus must be due to more indirect influences on the likely substrate binding site at the O5 bridging-oxygen position. PMID:24806267

Schraut, Johannes; Kaupp, Martin

2014-06-10

271

Indirect-Collective Referencing (ICR) in the Elite Journal Literature of Physics. II. A Literature Science Study on the Level of Communications.  

ERIC Educational Resources Information Center

Continues previous research on indirect-collective referencing (ICR) in physics literature, focusing on the level of communications and specific degree of documentedness of a communication. Explains ICR as a special kind of scientific referencing, mentioning references that are not indexed and hence not included in the Science Citation Index. (LRW)

Szava-Kovats, Endre

2002-01-01

272

Science research annual, volume II: a collection of science staff memoranda and letters from the Illinois Legislature Council - January-June 1980. Annual report Jan 80Sep 81  

Microsoft Academic Search

This volume contains a collection of correspondence and contributions from the Illinois Legislative Council. The memoranda, which have been organized into research reports, answer requests from individual legislators for information on specific science, technology, and public policy issues, and include information sources and pertinent legislation of the 81st Illinois General Assembly. Topics covered are as follows: abortion information; accidental deer

1981-01-01

273

Collection Development.  

ERIC Educational Resources Information Center

Includes 21 articles that discuss collection development in Canadian school libraries. Topics include digital collections in school library media centers; print and electronic library resources; library collections; collaborative projects; print-disabled students; informing administrators of the importance of collection development; censorship;…

School Libraries in Canada, 2002

2002-01-01

274

An examination of the kinetics and mechanisms of the chemical vapor deposition of aluminum nitride. (Volumes I and II)  

SciTech Connect

The kinetics and mechanisms of the chemical vapor deposition (CVD) of AlN[sub x]C[sub y] using diethylaluminum azide (DEAN[sub 3]), dimethylaluminum azide (DMAN[sub 3]), diethylaluminum amide (DEANH[sub 2]), and dimethylaluminum amide (DMANH[sub 2]) were examined. These reactions were investigated using mass spectrometry, temperature programmed reaction spectroscopy (TPRS), and isothermal reaction spectroscopy. Mechanistic pathways are proposed, and used to model the TPRS experimental results. The kinetic parameters for the rate limiting steps of the major reaction pathways are extracted as a result of the modeling. The azide functional groups were found to react (following first order kinetics) by liberating dinitrogen. The amide functional groups were found to be a source of hydrogen for protonolysis reactions. Also, the aluminum-amide bond was found to undergo a protonolysis reaction under certain conditions, liberating ammonia. The ethyl functional groups liberated, ethylene through [beta]-hydrogen elimination, ethane through protonolysis, and incorporated carbon through a dehydrogenation reaction. The methyl functional groups were proposed to generate methyl radicals through homolytic cleavage (the radicals presumably undergo a wall reaction to generate methane, the observed product), generate methane via protonolysis, and incorporate carbon via [alpha]-hydrogen abstraction.

Hanson, S.A.

1993-01-01

275

THE CHEMICAL ABUNDANCES OF STARS IN THE HALO (CASH) PROJECT. II. A SAMPLE OF 14 EXTREMELY METAL-POOR STARS ,  

SciTech Connect

We present a comprehensive abundance analysis of 20 elements for 16 new low-metallicity stars from the Chemical Abundances of Stars in the Halo (CASH) project. The abundances have been derived from both Hobby-Eberly Telescope High Resolution Spectrograph snapshot spectra (R {approx}15, 000) and corresponding high-resolution (R {approx}35, 000) Magellan Inamori Kyocera Echelle spectra. The stars span a metallicity range from [Fe/H] from -2.9 to -3.9, including four new stars with [Fe/H] < -3.7. We find four stars to be carbon-enhanced metal-poor (CEMP) stars, confirming the trend of increasing [C/Fe] abundance ratios with decreasing metallicity. Two of these objects can be classified as CEMP-no stars, adding to the growing number of these objects at [Fe/H]< - 3. We also find four neutron-capture-enhanced stars in the sample, one of which has [Eu/Fe] of 0.8 with clear r-process signatures. These pilot sample stars are the most metal-poor ([Fe/H] {approx}< -3.0) of the brightest stars included in CASH and are used to calibrate a newly developed, automated stellar parameter and abundance determination pipeline. This code will be used for the entire {approx}500 star CASH snapshot sample. We find that the pipeline results are statistically identical for snapshot spectra when compared to a traditional, manual analysis from a high-resolution spectrum.

Hollek, Julie K.; Sneden, Christopher; Shetrone, Matthew [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Frebel, Anna [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Roederer, Ian U. [Carnegie Observatories, Pasadena, CA 91101 (United States); Beers, Timothy C. [Department of Physics and Astronomy, and JINA: Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 (United States); Kang, Sung-ju [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Thom, Christopher, E-mail: julie@astro.as.utexas.edu, E-mail: chris@astro.as.utexas.edu, E-mail: shetrone@astro.as.utexas.edu, E-mail: afrebel@cfa.harvard.edu, E-mail: iur@obs.carnegiescience.edu, E-mail: beers@pa.msu.edu, E-mail: sjkang@iastate.edu, E-mail: cthom@stsci.edu [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

2011-11-20

276

Chemical defense collective protection technology. Volume 12. A procedure for recharging self-contained breathing apparatus air bottles in the presence of simulated chemical warfare agents. Final report, 6-11 September 1990  

SciTech Connect

A procedure was developed and tested for recharging Self-Contained Breathing Apparatus (SCBA) cylinders in an atmosphere contaminated with chemical agent simulant at concentrations which would produce casualties if actual agent were used. With the exception of a rack for storing the cylinders before and after recharging, all items used are currently available commercially or through off-the-shelf DOD supply sources. Cylinders were successfully recharged without contamination in the presence of chemical agent simulant in the compressor area as well as in the cylinder filling area. Inexperienced personnel easily learned and successfully followed the recharging procedures even though they were burdened by protective clothing and equipment. Chemical agents, SCBA, Firefighting, Self-contained breathing apparatus.

Conkle, J.P.; Tucker, D.M.; Moore, G.

1993-05-01

277

Mineralogical, Chemical and Biological Characterization of an Anaerobic Biofilm Collected from a Borehole in a Deep Gold Mine in South Africa  

Microsoft Academic Search

A biofilm sample was collected from an anaerobic water and gas-flowing borehole, 1.474 km below land surface in the Evander Au mine, Republic of South Africa. The biofilm was 27 wt% ZnS, which was ? 2 × 10times more concentrated than the dissolved Zn measured in the borehole water. X-Ray diffraction indicated that the Zn was present in the form

L. C. W. MacLean; T. J. Pray; T. C. Onstott; E. L. Brodie; T. C. Hazen; G. Southam

2007-01-01

278

Chemical weathering of a soil chronosequence on granitoid alluvium: II. Mineralogic and isotopic constraints on the behavior of strontium  

USGS Publications Warehouse

The use of strontium isotopes to evaluate mineral weathering and identify sources of base cations in catchment waters requires an understanding of the behavior of Sr in the soil environment as a function of time. Our approach is to model the temporal evolution of 87Sr/86Sr of the cation exchange pool in a soil chronosequence developed on alluvium derived from central Sierra Nevada granitoids during the past 3 Ma. With increasing soil age, 87Sr/86Sr of ammonium-acetate extractable Sr initially decreases from values typical of K-feldspar to those of plagioclase and hornblende and then remains constant, even though plagioclase and hornblende are absent from the soils after approximately 1 Ma of weathering. The temporal variation of 87Sr/86Sr of exchangeable Sr is modeled by progressively equilibrating Sr derived from mineral weathering and atmospheric deposition with Sr on exchange sites as waters infiltrate a soil column. Observed decreases in quartz-normalized modal abundances of plagioclase, hornblende, and K-feldspar with time, and the distinct 87Sr/86Sr values of these minerals can be used to calculate Sr flux from weathering reactions. Hydrobiotites in the soils have nearly constant modal abundances, chemistry, and 87Sr/86Sr over the chronosequence and provide negligible Sr input to weathering solutions. The model requires time and soil horizon-dependent changes in the amount of exchangeable Sr and the efficiency of Sr exchange, as well as a biologic cycling term. The model predicts that exchangeable Sr initially has 87Sr/86Sr identical to that of K-feldspar, and thus could be dominated by Sr leached from K-feldspar following deposition of the alluvium. The maximum value of 87Sr/86Sr observed in dilute stream waters associated with granitoids of the Yosemite region is likewise similar to that of the K-feldspars, suggesting that K-feldspar and not biotite may be the dominant source of radiogenic Sr in the streams. This study reveals that, when attempting to use Strontium isotopes to identify sources of base cations in catchment waters and biomass, both preferential leaching of Sr from minerals during incipient soil development and changing Sr exchange efficiency must be considered along with chemical contributions due to mineral dissolution. Copyright ?? 1997 Elsevier Science Ltd.

Bullen, T.; White, A.; Blum, A.; Harden, J.; Schulz, M.

1997-01-01

279

77 FR 28853 - Proposed Information Collection; Comment Request; Generic Clearance for Usability Data Collections  

Federal Register 2010, 2011, 2012, 2013

...required or regulated. The results of the data collected will be used to guide NIST research. Steps will be taken to ensure anonymity of respondents in each activity covered under this request. II. Method of Collection NIST will collect this...

2012-05-16

280

Chemical abundances of planetary nebulae from optical recombination lines - II. Abundances derived from collisionally excited lines and optical recombination lines  

NASA Astrophysics Data System (ADS)

In Paper I, we presented spectrophotometric measurements of emission lines from the ultraviolet (UV) to the far-infrared for 12 Galactic planetary nebulae (PNe) and derived nebular thermal and density structures using a variety of plasma diagnostics. The measurements and plasma diagnostic results are used in the current paper to determine elemental abundances in these nebulae. Abundance analyses are carried out using both strong collisionally excited lines (CELs) and weak optical recombination lines (ORLs) from heavy element ions. Assuming electron temperatures and densities derived from HI recombination spectra (line and continuum), we are able to determine the ORL C abundance relative to hydrogen for all the PNe in our sample, N and O abundances for 11 of them and Ne abundances for nine of them. In all cases, ORL abundances are found to be systematically higher than the corresponding values deduced from CELs. In NGC 40, the discrepancy between the abundances derived from the two types of emission line reaches a factor of 17 for oxygen. For the other 10 PNe, the discrepancies for oxygen vary from 1.6 to 3.1. In general, collisionally excited infrared fine-structure lines, which have excitation energies less than 103 K and consequently emissivities that are insensitive to electron temperature and temperature fluctuations, yield ionic abundances comparable to those derived from optical/UV CELs. For a given nebula, the discrepancies between the ORL and CEL abundances are of similar magnitude for different elements. In other words, relative abundance ratios such as C/O, N/O and Ne/O deduced from the traditional method based on strong CELs are comparable to those yielded by ORLs, for a wide range of ORL to CEL oxygen abundance ratios, varying from near unity to over a factor of 20. We have also determined ORL abundances relative to hydrogen for the third-row element magnesium for 11 nebulae in our sample. In strong contrast to the cases for second-row elements, Mg abundances derived from the MgII 3d-4f ?4481 ORL are nearly constant for all the PNe analysed so far and agree within the uncertainties with the solar photospheric value. In accordance with results from previous studies, the ORL to CEL abundance ratio is correlated with the difference between the electron temperatures derived from the [OIII] forbidden-line ratio, on the one hand, and from the hydrogen recombination Balmer discontinuity, on the other. We find that the discrepancy between the ORL and CEL abundances is correlated with nebular absolute diameter, surface brightness, the electron density derived from [SII] CELs, and excitation class. The results confirm that the dichotomy of temperatures and heavy elemental abundances determined from the two types of emission line, which has been widely observed in PNe, is a strong function of nebular evolution, as first pointed out by Garnett and Dinerstein. Our analyses show that temperature fluctuations and/or density inhomogeneities are incapable of explaining the large discrepancies between the heavy elemental abundances and electron temperatures determined from the two types of emission line. Our analyses support the bi-abundance model of Liu et al., who have proposed that PNe contain another previously unseen component of ionized gas which, highly enriched in heavy elements, has an electron temperature of <~103 K and emits strongly in recombination lines but not in CELs. Our determinations of low average emission temperatures from the observed line intensity ratios of HeI and OII ORLs lend further support to this scenario.

Liu, Y.; Liu, X.-W.; Barlow, M. J.; Luo, S.-G.

2004-10-01

281

Long-term chemical carcinogenesis experiments for identifying potential human cancer hazards: collective database of the National Cancer Institute and National Toxicology Program (1976-1991).  

PubMed Central

The carcinogenicity database used for this paper originated in the late 1960s by the National Cancer Institute (NCI) and since 1978 has been continued and made more comprehensive by the National Toxicology Program (NTP). The extensive files contain, among other sets of information, detailed pathology data on more than 400 long-term (most often 24-month) chemical carcinogenesis studies, comprising nearly 1600 individual experiments having at least 10 million tissue sections that have been evaluated for toxicity and carcinogenicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Huff, J; Haseman, J

1991-01-01

282

Collecting apparatus  

DOEpatents

An improved collecting apparatus for small aquatic or airborne organisms such as plankton, larval fish, insects, etc. The improvement constitutes an apertured removal container within which is retained a collecting bag, and which is secured at the apex of a conical collecting net. Such collectors are towed behind a vessel or vehicle with the open end of the conical net facing forward for trapping the aquatic or airborne organisms within the collecting bag, while allowing the water or air to pass through the apertures in the container. The container is readily removable from the collecting net whereby the collecting bag can be quickly removed and replaced for further sample collection. The collecting bag is provided with means for preventing the bag from being pulled into the container by the water or air flowing therethrough.

Duncan, Charles P. (Walnut Creek, CA)

1983-01-01

283

Polymeric Systems for Amorphous ?9-Tetrahydrocannabinol Produced by a Hot-Melt Method. Part II: Effect of Oxidation Mechanisms and Chemical Interactions on Stability  

PubMed Central

The objectives of the present research investigations were to (i) elucidate the mechanism for the oxidative degradation of ?9-tetrahydrocannabinol (THC) in polymer matrix systems prepared by a hot-melt fabrication procedure, and (ii) study the potential for controlling these mechanisms to reduce the degradation of THC in solid dosage formulations. Various factors considered and applied included drug-excipient compatibility, use of antioxidants, cross-linking in polymeric matrices, microenvironment pH, and moisture effect. Instability of THC in polyethylene oxide (PEO)-vitamin E succinate (VES) patches was determined to be due to chemical interaction between the drug and the vitamin as well as with the atmospheric oxygen. Of the different classes and mechanisms of antioxidants studied, quenching of oxygen by reducing agents, namely, ascorbic acid was the most effective in stabilizing THC in PEO-VES matrices. Only 5.8% of the drug degraded in the ascorbic acid-containing patch as compared to the control (31.6%) after 2 months of storage at 40°C. This coupled with the cross-linking extent and adjustment of the pH microenvironment, which seemed to have an impact on the THC degradation, might be effectively utilized towards stabilization of the drug in these polymeric matrices and other pharmaceutical dosage forms. These studies are relevant to the development of a stable transmucosal matrix system for the therapeutic delivery of amorphous THC.

MUNJAL, MANISH; ELSOHLY, MAHMOUD A.; REPKA, MICHAEL A.

2010-01-01

284

Strain-balanced InAs/GaSb type-II superlattice structures and photodiodes grown on InAs substrates by metalorganic chemical vapor deposition  

NASA Astrophysics Data System (ADS)

We propose and demonstrate strain-balanced InAs/GaSb type-II superlattices (T2SLs) grown on InAs substrates employing GaAs-like interfacial (IF) layers by metalorganic chemical vapor deposition (MOCVD) for effective strain management, simplified growth scheme, improved materials crystalline quality, and reduced substrate absorption. The in-plane compressive strain from the GaSb layers in the T2SLs on the InAs was completely balanced by the GaAs-like IF layers formed by controlled precursor carry-over and anion exchange effects, avoiding the use of complicated IF layers and precursor switching schemes that were used for the MOCVD growth of T2SLs on GaSb. An infrared (IR) p-i-n photodiode structure with 320-period InAs/GaSb T2SLs on InAs was grown and the fabricated devices show improved performance characteristics with a peak responsivity of ~1.9 A/W and a detectivity of ~6.78 × 109 Jones at 8 ?m at 78 K. In addition, the InAs buffer layer and substrate show a lower IR absorption coefficient than GaSb substrates in most of the mid- and long-IR spectral range.

Huang, Yong; Ryou, Jae-Hyun; Dupuis, Russell D.; Zuo, Daniel; Kesler, Benjamin; Chuang, Shun-Lien; Hu, Hefei; Kim, Kyou-Hyun; Ting Lu, Yen; Hsieh, K. C.; Zuo, Jian-Min

2011-07-01

285

Palladium(II) chemically bonded to silica surface applied to the separation and identification of polycyclic aromatic sulfur heterocycles in heavy oil.  

PubMed

Separation of polycyclic aromatic sulfur heterocycles among themselves and also from interferents in petrochemical matrices is a challenging task because of their low concentration, matrix complexity, and also due to the presence of polyaromatic hydrocarbons, as they present similar physico-chemical properties. Therefore, the objective of this work was preparation, characterization, and application of a stationary phase for separation of these compounds in a heavy gas oil sample and their identification by comprehensive two-dimensional gas chromatography. The stationary phase was prepared by grafting mercaptopropyltrimethoxisilane onto a silica surface, followed by palladium(II) chloride immobilization. Elemental analysis, thermogravimetry, nitrogen adsorption-desorption isotherms, infrared analysis, and scanning electron microscopy were performed to characterize this solid phase. Sulfur compounds were separated in an open column packed with the stationary phase and analyzed by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometric detection. The number of compounds tentatively identified was 314 and their classes were thiophenes, benzotiophenes, dibenzothiophenes, naphthothiophenes, benzonaphthothiophenes, and dinaphthothiophenes. Separation among sulfur compounds and polyaromatic hydrocarbons was successful, which is a difficult goal to achieve with the traditionally employed solid phases. Some recalcitrant compounds (dibenzothiophenes with substituents of two and four carbons) were fully separated and tentatively identified. PMID:23596144

Machado, Maria Elisabete; de Menezes, Eliana Weber; Bregles, Lucas Panizzi; Caramão, Elina Bastos; Benvenutti, Edilson Valmir; Zini, Cláudia Alcaraz

2013-05-01

286

Chemical defense collective protection technology. Volume 12. A procedure for recharging self-contained breathing apparatus air bottles in the presence of simulated chemical warfare agents. Final report, 6-11 September 1990  

Microsoft Academic Search

A procedure was developed and tested for recharging Self-Contained Breathing Apparatus (SCBA) cylinders in an atmosphere contaminated with chemical agent simulant at concentrations which would produce casualties if actual agent were used. With the exception of a rack for storing the cylinders before and after recharging, all items used are currently available commercially or through off-the-shelf DOD supply sources. Cylinders

J. P. Conkle; D. M. Tucker; G. Moore

1993-01-01

287

Chemical analyses of soil samples collected from the vicinity of the thermal test complex at Sandia National Laboratories, New Mexico environs, 2006.  

SciTech Connect

In the summer of 2006, the Environmental Programs and Assurance Department of Sandia National Laboratories in Albuquerque, New Mexico (SNL/NM), collected surface soil samples at 37 locations within one mile of the vicinity of the newly constructed Thermal Test Complex (TTC) for the purpose of determining baseline conditions against which potential future impacts to the environs from operations at the facility could be assessed. These samples were submitted to an offsite analytical laboratory for metal-in-soil analyses. This work provided the SNL Environmental Programs and Assurance Department with a sound baseline data reference set against which to assess potential future operational impacts at the TTC. In addition, it demonstrates the commitment that the Laboratories have to go beyond mere compliance to achieve excellence in its operations. This data are presented in graphical format with narrative commentaries on particular items of interest.

Miller, Mark Laverne; Nieto, Danielle M.

2007-01-01

288

Guidelines for sample collecting and analytical methods used in the U.S. Geological Survey for determining chemical composition of coal  

USGS Publications Warehouse

This report is intended to meet the many requests for information on current U.S. Geological Survey procedures in handling coal samples. In general, the exact type and number of samples of coal and associated rock to be collected are left to the best judgment of the geologist. Samples should be of unweathered coal or rock and representative of the bed or beds sampled; it is recommended that two channel samples, separated by 10 to 100 yards (10 to 100 metres) and weighing 4 to 5 pounds ( 1.8 to 2.3 kilograms) each, be collected of each 5 feet ( 1.5 metres) of vertical section. Care must be taken to avoid any sample contamination, and to record the exact locality, thickness, and stratigraphic information for each sample. Analytical methods are described for the determination of major, minor, and trace elements in coal. Hg, As, Sb, F, Se, U, and Th are determined in the raw coal, and the following 34 elements are determined after ashing the coal: Si, Al, Ca, Mg, Na, K, Fe (total), Cl, Ti, Mn, P, S (total), Cd, Li, Cu, Zn, Pb, B, Ba, Be, Co, Cr, Ga, La, Mo, Nb, Ni, Sc, Sr, Ti, V, Y, Yb, and Zr. The methods used to determine these elements include atomic absorption spectroscopy, X-ray fluorescence spectroscopy, optical emission spectroscopy, spectrophotometry, selective-ion electrode, and neutron activation analysis. A split of representative coal samples is submitted to the U.S. Bureau of Mines for proximate, ultimate, forms of sulfur, and Btu determinations.

Swanson, Vernon Emanuel; Huffman, Claude

1976-01-01

289

Collection Mapping and Collection Development.  

ERIC Educational Resources Information Center

Describes the use of collection mapping to assess media collections of Aurora, Colorado, Public Schools. Case studies of elementary, middle, and high school media centers describe materials selection and weeding and identify philosophies that library collections should support school curriculum, and teacher-library media specialist cooperation in…

Murray, William; And Others

1985-01-01

290

Western fence lizard (Sceloporus occidentalis) chemical signals. II. A replication with naturally breeding adults and a test of the Cowles and Phelan hypothesis of rattlesnake olfaction.  

PubMed

The capacity of naturally breeding western fence lizards (Sceloporus occidentalis biseriatus) to discriminate and respond to conspecific and control chemical cues was examined. Lizards were presented with markings and exudates of male and female donors, as well as cologne (a pungency control) and water, in a successive discrimination procedure. Behavioral actions quantified after exposure to the different chemical cue types included lingual extrusions (tongue flicks and substrate licks), rapid nasal inhalations, and the performance of push-up visual displays. Initial latencies to lingual investigation of the different extracts and markings also were recorded as a measure of the extent to which nasal olfaction would switch on the tongue-Jacobson's organ (vomeronasal olfactory) system. Although no sex differences in total levels of response were noted, males and females exhibited significant lingual discriminations equally to exudates collected from male or female conspecifics. Push-up visual displays also were noted in response to conspecific markings. Cologne-marked surfaced, however, elicited nonsignificant levels of lingual investigation and push-up displaying. Latencies to initial tongue flicks, but not substrate licks, were significantly shorter when any material other than water was present. Therefore, as suggested by Cowles and Phelan ('58), nasal olfaction may indeed be more of a "quantitative," distance sensing system that responds to the presence of any pungent substance by initiating further investigation via the tongue-Jacobson's organ system. The latter appears to be more "qualitative," or discriminating, as indexed by relatively greater levels of lingual investigation of conspecific markings than cologne. No differences were noted in rapid nasal inhalation activity. The results suggest that pheromone markings, along the ground or other surfaces, may be important to spacing and territorial maintenance in nature. This could occur through direct pheromone effects on signal recipients, or indirectly, through the stimulation of increased push-up activity, which could make lizards more visible to one another. PMID:7338721

Duvall, D

1981-12-01

291

Analysis of chemical constituents and antinociceptive potential of essential oil of Teucrium Stocksianum bioss collected from the North West of Pakistan  

PubMed Central

Background Medicinal plants are used for the treatment of different diseases in almost all cultures. Teucrium species grow wildly at different geographical locations around the world. Teucrium stocksianum is used in folk medicine for the treatment of diarrhea, cough, jaundice and abdominal pain. Scientific study on Teucrium stocksianum shows that it possesses anthelmintic, cytotoxic and antispasmodic activity. The aim of our present study is to identify the chemical composition and antinociceptive potential of the essential oil extracted from Teucrium stocksianum bioss. Method Essential oil (EO) from the aerial parts of Teucrium stocksianum were extracted by hydrodistillation process. The qualitative and quantitative composition of essential oil was determined with Gas chromatography/Mass spectrometer. Antinociceptive activity was determined by acetic acid induced writhing method. Percent inhibition of writhes of the test concentration was determined by comparing it with that of control. Tween-80 emulsion 2.5% (5?ml/kg b.w) was used as a control while Diclofenic sodium 50?mg/kg (b.w) was used as a standard drug. Results The chromatogram of the essential oil of Teucrium stocksianum shows differences both qualitatively and quantatively from essential oil composition reported in other countries. Hydrodistillation of Teucrium stocksianum yielded 0.4% (v/w), pale yellowish oil on dry basis. A total of 26 chemicals were identified by GC-MS accounting for 90.28% of the oil. The major components of essential oil were ?-cadinene (12.92%), ?-pinene (10.3%), myrcene (8.64%), ?-caryophyllene (8.23%), germacrene D (5.18%) and limonene (2.36%). Essential oil of Teucrium stocksianum has shown outstanding antinociceptive activity. It has been observed that increase in percent writhe inhibition (PWI) occurred from 20-80?mg/kg (b.w) and maximum writhe inhibition has been noted at a concentration of 80?mg/kg (b.w), but PWI decreased at 160?mg/kg, which may be due to some toxic effect of higher dose. ED50 value for Teucrium stocksianum was calculated as 31.5?±?1.72415?mg/kg (b.w). Conclusion Our results indicate that there is a lot of variation in the composition of essential oil of Teucrium stocksianum boiss, which may be due to different climatic and experimental conditions. Secondly, the essential oil possesses strong antinociceptive activity and could be used in analgesic preparations especially for topical use.

2012-01-01

292

A Collection of Chemical, Mineralogical, and Stable Isotopic Compositional Data for Green River Oil Shale from Depositional Center Cores in Colorado, Utah, and Wyoming  

USGS Publications Warehouse

For over half a century, the U.S. Geological Survey and collaborators have conducted stratigraphic and geochemical studies on the Eocene Green River Formation, which is known to contain large oil shale resources. Many of the studies were undertaken in the 1970s during the last oil shale boom. One such study analyzed the chemistry, mineralogy, and stable isotopy of the Green River Formation in the three major depositional basins: Piceance basin, Colo.; Uinta basin, Utah; and the Green River basin, Wyo. One depositional-center core from each basin was sampled and analyzed for major, minor, and trace chemistry; mineral composition and sulfide-mineral morphology; sulfur, nitrogen, and carbon forms; and stable isotopic composition (delta34S, delta15N, delta13C, and delta18O). Many of these data were published and used to support interpretative papers (see references herein). Some bulk-chemical and carbonate-isotopic data were never published and may be useful to studies that are currently exploring topics such as future oil shale development and the climate, geography, and weathering in the Eocene Epoch. These unpublished data, together with most of the U.S. Geological Survey data already published on these samples, are tabulated in this report.

Tuttle, Michele L. W.

2009-01-01

293

75 FR 8996 - Notice of Information Collection  

Federal Register 2010, 2011, 2012, 2013

...opportunities will be available, representing all NASA Mission Directorates and current NASA missions in Earth and Space Science, mathematics, chemistry, and physics. II. Method of Collection The data collection uses web-based...

2010-02-26

294

Trace metals in PM10 and PM 2.5 samples collected in a highly industrialized chemical/petrochemical area and its urbanized surroundings.  

PubMed

The aim of this study was to determine the potential impact of a highly industrialized area on its urbanized surroundings. The area studied is home to a refinery, a thermoelectric plant and several petrochemical facilities industries. The concentrations of twelve elements were determined in PM10 and PM2.5 samples collected along a busy highway and near the petrochemical complex. Significantly higher concentrations of Ca, Mg, Mn, Fe, Cu and Al were observed in the petrochemical zone, but principal component analysis revealed similar patterns for both the highway site and a site approximately 1.5 km from the petrochemical complex, suggesting that the main pollution source in the area is vehicular flux. Higher concentrations in the industrial area may be attributed to intense diesel-powered truck and bus traffic movement, mainly due to the transport of supplies, fuel and gas. The observed concentrations of the elements Cr, Co, Ni, Cd and Pb were always lower than the detection limits of the technique used. PMID:24509656

dos Anjos Paulino, Silvia; Oliveira, Rafael Lopes; Loyola, Josiane; Minho, Alan Silva; Arbilla, Graciela; Quiterio, Simone Lorena; Escaleira, Viviane

2014-05-01

295

Injectable PLA-based in situ forming implants for controlled release of Ivermectin a BCS Class II drug: solvent selection based on physico-chemical characterization.  

PubMed

In situ forming implants (ISI) prepared from biodegradable polymers such as poly(D,L-lactide) (PLA) and biocompatible solvents can be used to obtain sustained drug release after parenteral administration. The aim of this work was to study the effect of several biocompatible solvents with different physico-chemical properties on the release of ivermectin (IVM), an antiparasitic BCS II drug, from in situ forming PLA-based implants. The solvents evaluated were N-methyl-2-pyrrolidone (NMP), 2-pyrrolidone (2P), triacetine (TA) and benzyl benzoate (BB). Hansen's solubility parameters of solvents were used to explain polymer/solvent interactions leading to different rheological behaviours. The stability of the polymer and drug in the solvents were also evaluated by size exclusion and high performance liquid chromatography, respectively. The two major factors determining the rate of IVM release from ISI were miscibility of the solvent with water and the viscosity of the polymer solutions. In general, the release rate increased with increasing water miscibility of the solvent and decreasing viscosity in the following order NMP>2P>TA>BB. Scanning electron microscopy revealed a relationship between the rate of IVM release and the surface porosity of the implants, release being higher as implant porosity increased. Finally, drug and polymer stability in the solvents followed the same trends, increasing when polymer-solvent affinities and water content in solvents decreased. IVM degradation was accelerated by the acid environment generated by the degradation of the polymer but the drug did not affect PLA stability. PMID:22397675

Camargo, J A; Sapin, A; Nouvel, C; Daloz, D; Leonard, M; Bonneaux, F; Six, J-L; Maincent, P

2013-01-01

296

Characterization of singlet oxygen production and its involvement in photodamage of Photosystem II in the cyanobacterium Synechocystis PCC 6803 by histidine-mediated chemical trapping.  

PubMed

Singlet oxygen production in intact cells of the cynobacterium Synechocystis 6803 was studied using chemical trapping by histidine, which leads to O2 uptake during illumination. The rate of O2 uptake, measured by a standard Clark-type electrode, is enhanced in the presence of D2O, which increases the lifetime of (1)O2, and suppressed by the (1)O2 quencher NaN3. Due to the limited mobility of (1)O2 these data demonstrate that exogenous histidine reaches close vicinity of (1)O2 production sites inside the cells. Flash induced chlorophyll fluorescence measurements showed that histidine does not inhibit Photosystem II activity up to 5mM concentration. By applying the histidine-mediated O2 uptake method we showed that (1)O2 production linearly increases with light intensity even above the saturation of photosynthesis. We also studied (1)O2 production in site directed mutants in which the Gln residue at the 130th position of the D1 reaction center subunit was changed to either Glu or Leu, which affect the efficiency of nonradiative charge recombination from the primary radical pair (Rappaport et al. 2002, Biochemistry 41: 8518-8527; Cser and Vass 2007, BBA 1767:233-243). We found that the D1-Gln130Glu mutant showed decreased (1)O2 production concomitant with decreased rate of photodamage relative to the WT, whereas both (1)O2 production and photodamage were enhanced in the D1-Gln130Leu mutant. The data are discussed in the framework of the model of photoinhibition in which (3)P680 mediated (1)O2 production plays a key role in PSII photodamage, and nonradiative charge recombination of the primary charge separated state provides a photoprotective pathway. PMID:23466334

Rehman, Ateeq Ur; Cser, Krisztián; Sass, László; Vass, Imre

2013-06-01

297

Jay's Collectibles  

ERIC Educational Resources Information Center

There is growing interest in collectibles of many types, as indicated by the popularity of television programs such as the History Channel's "Pawn Stars" and "American Pickers" and the Public Broadcasting Service's "Antiques Road Show." The availability of online auction sites such as eBay has enabled many people to collect items of interest as a…

Cappel, James J.; Gillman, Jason R., Jr.

2011-01-01

298

Collective invention  

Microsoft Academic Search

This paper argues that many new production techniques have been developed by a process called 'collective invention'. When firms collectively invent, they make available to their competitors the results of new plant designs so that their competitors can incorporate extensions of those designs into new facilities they build. The paper analyses the implications of this behavior for the rate and

Robert C. Allen

1983-01-01

299

Collective Bargaining.  

ERIC Educational Resources Information Center

This chapter discusses litigation touching on collective bargaining issues. The chapter is organized to follow the collective bargaining process, from cases dealing with union organizing to cases involving arbitration. Issues covered also include determination of bargaining units, scope of bargaining, union security, and unfair labor practices in…

Zirkel, Perry A.

300

Chemical interference of pathogen-associated molecular pattern-triggered immune responses in Arabidopsis reveals a potential role for fatty-acid synthase type II complex-derived lipid signals.  

PubMed

We describe an experimental setup using submerged cultures of Arabidopsis seedlings in 96-well microtiter plates that permits chemical intervention of rapid elicitor-mediated immune responses. Screening of a chemical library comprising 120 small molecules with known biological activities revealed four compounds reducing cellulysin- or flg22-activated gene expression of the early pathogen-associated molecular patterns (PAMP)-responsive ATL2 gene. One chemical, oxytriazine, was found to induce ATL2 gene expression in the absence of PAMP. By monitoring additional flg22-triggered immediate early plant responses, we present evidence that two compounds, triclosan and fluazinam, interfere with the accumulation of reactive oxygen species and internalization of the activated plasma membrane resident FLS2 immune receptor. Using triclosan structure types and enzyme activity inhibition assays, Arabidopsis MOD1 enoyl-acyl carrier protein reductase, a subunit of the fatty-acid synthase type II (FAS II) complex, was identified as a likely cellular target of triclosan. Inhibition of all tested elicitor-triggered early immune responses by triclosan indicates a potential role for signaling lipids in flg22-triggered immunity. Chemical profiling of eca mutants, each showing deregulated ATL2 gene expression, with the identified compounds revealed mutantspecific response patterns and allowed us to deduce tentative action sites of ECA genes relative to the compound targets. PMID:17166839

Serrano, Mario; Robatzek, Silke; Torres, Martha; Kombrink, Erich; Somssich, Imre E; Robinson, Mike; Schulze-Lefert, Paul

2007-03-01

301

Micrometeorite Collecting  

ERIC Educational Resources Information Center

Describes how to collect micrometeorites and suggests a number of related activities such as determining the number of meteors entering the atmosphere and determining the composition of the micrometeorites. (BR)

Toubes, Joe; Hoff, Darrel

1974-01-01

302

Spoon Collective  

NSDL National Science Digital Library

The Spoon Collective houses descriptive information, discussion archives, paper archives, and links to Websites for three dozen listservs related to the discussion of philosophy, sociology, political science, and literary theory. Some of the topics for the lists include Postcolonialism, Poststructuralism, Feminism, Marxism, and Cultural Studies. Thirteen of the lists are dedicated to the work of influential thinkers, including Jean Baudrillard, Pierre Bourdieu, Michel Foucault, Friedrich Nietzsche, and Martin Heidegger. All content at the Spoon Collective can be searched aggregately.

303

Integrated Procurement Management System, Version II  

NASA Technical Reports Server (NTRS)

Integrated Procurement Management System, Version II (IPMS II) is online/ batch system for collecting developing, managing and disseminating procurementrelated data at NASA Johnson Space Center. Portions of IPMS II adaptable to other procurement situations.

Collier, L. J.

1985-01-01

304

Mixed ligand ?-phenoxo-bridged dinuclear copper(II) complexes with diimine co-ligands: efficient chemical nuclease and protease activities and cytotoxicity.  

PubMed

The water soluble mixed ligand copper(II) complexes of the type [Cu(sal)(diimine)(ClO4)]21-5, where sal is salicylaldehyde and diimine is 2,2'-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2), 5,6-dimethyl-1,10-phenanthroline (5,6-dmp, 3), 3,4,7,8-tetramethyl-1,10-phenanthroline (3,4,7,8-tmp, 4) or dipyrido[3,2-d:2',3'-f]quinoxaline (dpq, 5), and [Cu(sal)(phen)(NO3)]2 (2a) have been successfully isolated and characterized by elemental analysis and other spectral techniques. The DNA binding and cleavage properties of 1-5 have been explored by using various physical and biochemical methods. The coordination geometry around copper(II) in the X-ray structures of 1, 2, 2a and 4 is described as an elongated octahedron. The UV-Vis and EPR spectral and ESI-MS studies reveal that in solution the dinuclear complexes dissociate into essentially mononuclear [Cu(sal)(diimine)]+ species with square-based geometry. The absorption spectral titrations and competitive DNA binding studies reveal that the intrinsic DNA binding affinity of the complexes depends upon the diimine co-ligand and is of the order of dpq (5) > 3,4,7,8-tmp (4) > 5,6-dmp (3) > phen (2) > bpy (1). The complexes 2 and 5 are involved in a partial intercalative interaction with DNA base pairs, while 3 and 4 are involved in a hydrophobic interaction with DNA and 1 is involved in an electrostatic interaction with DNA, which is supported by viscosity studies. Interestingly, only 3 and 4 are selective in exhibiting a positive induced CD band (ICD) upon binding to DNA suggesting that they induce a B to A conformational change in DNA. All the complexes exhibit an oxidative DNA cleavage ability, which varies as 5 > 4 > 3 > 2 > 1. While 4 and 5 are unique in displaying prominent double-strand DNA cleavage even in the absence of an activator, 2 and 3 display only single-strand DNA cleavage. Interestingly, all the complexes exhibit oxidative double-strand DNA cleavage in the presence of ascorbic acid, with 4 and 5 showing a DNA cleavage activity more prominent than 1 and 2. The ability of the complexes to bind and cleave the protein BSA varies in the order, 4 > 3 > 5 > 2 > 1. Interestingly, 3 and 4 cleave the protein in the presence of H2O2 as an activator in a non-specific manner suggesting that they can act as chemical proteases. It is remarkable that all the complexes exhibit cytotoxicity against human breast cancer cell lines (MCF-7) with a potency more than the widely used drug cisplatin indicating that they have the potential to act as effective anticancer drugs in a time dependent manner. The morphological assessment data obtained by using Hoechst 33258 staining reveal that 3 and 4 induce apoptosis much more effectively than the other complexes. Also, the alkaline single-cell gel electrophoresis study (comet assay) suggests that the same complexes induce DNA fragmentation more efficiently than others. PMID:24595529

Loganathan, Rangasamy; Ramakrishnan, Sethu; Suresh, Eringathodi; Palaniandavar, Mallayan; Riyasdeen, Anvarbatcha; Akbarsha, Mohamad Abdulkadhar

2014-04-28

305

THE SPLASH SURVEY: INTERNAL KINEMATICS, CHEMICAL ABUNDANCES, AND MASSES OF THE ANDROMEDA I, II, III, VII, X, AND XIV DWARF SPHEROIDAL GALAXIES {sup ,}  

SciTech Connect

We present new Keck/DEIMOS spectroscopic observations of hundreds of individual stars along the sightline to the first three of the Andromeda (M31) dwarf spheroidal (dSph) galaxies to be discovered, And I, II, and III, and combine them with recent spectroscopic studies by our team of three additional M31 dSphs, And VII, X, and XIV, as a part of the SPLASH Survey (Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo). Member stars of each dSph are isolated from foreground Milky Way dwarf stars and M31 field contamination using a variety of photometric and spectroscopic diagnostics. Our final spectroscopic sample of member stars in each dSph, for which we measure accurate radial velocities with a median uncertainty (random plus systematic errors) of 4-5 km s{sup -1}, includes 80 red giants in And I, 95 in And II, 43 in And III, 18 in And VII, 22 in And X, and 38 in And XIV. The sample of confirmed members in the six dSphs is used to derive each system's mean radial velocity, intrinsic central velocity dispersion, mean abundance, abundance spread, and dynamical mass. This combined data set presents us with a unique opportunity to perform the first systematic comparison of the global properties (e.g., metallicities, sizes, and dark matter masses) of one-third of Andromeda's total known dSph population with Milky Way counterparts of the same luminosity. Our overall comparisons indicate that the family of dSphs in these two hosts have both similarities and differences. For example, we find that the luminosity-metallicity relation is very similar between L {approx} 10{sup 5} and 10{sup 7} L{sub sun}, suggesting that the chemical evolution histories of each group of dSphs are similar. The lowest luminosity M31 dSphs appear to deviate from the relation, possibly suggesting tidal stripping. Previous observations have noted that the sizes of M31's brightest dSphs are systematically larger than Milky Way satellites of similar luminosity. At lower luminosities between L = 10{sup 4} and 10{sup 6} L{sub sun}, we find that the sizes of dSphs in the two hosts significantly overlap and that four of the faintest M31 dSphs are smaller than Milky Way counterparts. The first dynamical mass measurements of six M31 dSphs over a large range in luminosity indicate similar mass-to-light ratios compared to Milky Way dSphs among the brighter satellites, and smaller mass-to-light ratios among the fainter satellites. Combined with their similar or larger sizes at these luminosities, these results hint that the M31 dSphs are systematically less dense than Milky Way dSphs. The implications of these similarities and differences for general understanding of galaxy formation and evolution are summarized.

Kalirai, Jason S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Beaton, Rachael L.; Majewski, Steven R.; Ostheimer, James C.; Patterson, Richard J. [Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903 (United States); Geha, Marla C. [Astronomy Department, Yale University, New Haven, CT 06510 (United States); Gilbert, Karoline M. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Guhathakurta, Puragra; Kirby, Evan N. [University of California Observatories/Lick Observatory, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Wolf, Joe, E-mail: jkalirai@stsci.ed, E-mail: rlb9n@virginia.ed, E-mail: srm4n@virginia.ed, E-mail: rjp0i@virginia.ed, E-mail: marla.geha@yale.ed, E-mail: kgilbert@astro.washington.ed, E-mail: raja@ucolick.or, E-mail: enk@astro.caltech.ed, E-mail: wolfj@uci.ed [Center for Cosmology, Department of Physics and Astronomy, University of California at Irvine, Irvine, CA 92697 (United States)

2010-03-10

306

Carnival Collection  

NSDL National Science Digital Library

"Come to the carnival" is a common refrain in New Orleans during the month of February, and this intoxicating collection from Tulane University pays homage to this wonderful cultural tradition. The collection includes over 1,500 float designs from the "Golden Age" of carnival by notable designers such as Jennie Wilde, B.A. Wikstrom, and Charles Briton. Support for the project comes from the late Charles L. "Pie" Dufour who left funds to continue the preservation of these rare and unique ephemeral materials. Visitors can browse at their leisure, and they may wish to start with fanciful designs like the 1870 "Twelfth Night Revelers" float or the 1891 "Atlanteans" design. Also, visitors can select the work of a particular float designer or krewe of note. Also, visitors can search the entire collection by keyword.

2012-02-24

307

Blood Collection  

NASA Technical Reports Server (NTRS)

The method that is used for the collection, storage and real-time analysis of blood and other bodily fluids has been licensed to DBCD, Inc. by NASA. The result of this patent licensing agreement has been the development of a commercial product that can provide serum or plasma from whole blood volumes of 20 microliters to 4 milliliters. The device has a fibrous filter with a pore size of less than about 3 microns, and is coated with a mixture of mannitol and plasma fraction protein. The coating causes the cellular fraction to be trapped by the small pores, leaving the cellular fraction intact on the fibrous filter while the acellular fraction passes through the filter for collection in unaltered form from the serum sample collection chamber. The method used by this product is useful to NASA for blood analysis on manned space missions.

1999-01-01

308

Holocaust Collection.  

National Technical Information Service (NTIS)

This is a Collection/Package of two (2) printed documents and 2 VHS videos that provide background and historical information on the Holocaust that is available from NTIS' database. The reports and videos were prepared or sponsored by various federal agen...

1995-01-01

309

Collecting Artifacts  

ERIC Educational Resources Information Center

Fresh out of college, the author had only a handful of items worthy of displaying, which included some fossils she had collected in her paleontology class. She had binders filled with great science information, but kids want to see "real" science, not paper science. Then it came to her: she could fill the shelves with science artifacts with the…

Coffey, Natalie

2004-01-01

310

Wastewater Collection.  

ERIC Educational Resources Information Center

Presents a literature review of wastewater collection systems and components. This review covers: (1) planning, (2) construction; (3) sewer system evaluation; (4) maintenance; (5) rehabilitation; (6) overview prevention; and (7) wastewater pumping. A list of 111 references is also presented. (HM)

Chatterjee, Samar; And Others

1978-01-01

311

Collective Bargaining.  

ERIC Educational Resources Information Center

This chapter deals with the legal process by which employers and employee organizations discuss matters related to employment. The chapter is organized to reflect the initial sequence of events in the collective bargaining process. Cases are reported and analyzed in nine sections: obligation and authority to bargain; unit determination and…

Goldschmidt, Steven M.

312

Collective Bargaining.  

ERIC Educational Resources Information Center

This chapter summarizes recent state supreme court and federal court decisions involving collective bargaining for employees of public educational institutions. The cases discussed are generally limited to those decided during 1975 and reported in the General Digest as of March 1976. In his discussion, the author attempts to integrate related…

Goldschmidt, Steven M.

313

Accurate prediction of 195Pt NMR chemical shifts for a series of Pt(II) and Pt(IV) antitumor agents by a non-relativistic DFT computational protocol.  

PubMed

The GIAO-PBE0/SARC-ZORA(Pt)?6-31+G(d)(E) (E = main group element) computational protocol without including relativistic and spin-orbit effects is offered here for the accurate prediction of the (195)Pt NMR chemical shifts of a series of cis-(amine)2PtX2 (X = Cl, Br, I) anticancer agents (in total 42 complexes) and cis-diacetylbis(amine)platinum(II) complexes (in total 12) in solutions employing the Polarizable Continuum Model (PCM) solvation model, thus contributing to the difficult task of computation of (195)Pt NMR. Calculations of the torsional energy curves along the diabatic (unrelaxed) rotation around the Pt-N bond of the cis-(amine)2PtX2 (X = Cl, Br, I) anticancer agents revealed the high sensitivity of the (195)Pt NMR chemical shifts to conformational changes. The crucial effect of the conformational preferences on the electron density of the Pt central atom and consequently on the calculated ?(195)Pt chemical shifts was also corroborated by the excellent linear plots of ?(calcd)((195)Pt) chemical shifts vs. the natural atomic charge Q(Pt). Furthermore, for the accurate prediction of the (195)Pt NMR chemical shifts of the cis-bis(amine)Pt(II) anticancer agents bearing carboxylato- as the leaving ligands (in total 8) and a series of octahedral Pt(IV) antitumor agents (in total 20 complexes) the non-relativistic GIAO-PBE0/SARC-ZORA(Pt)?6-31+G(d)(E) computational protocol performs best in combination with the universal continuum solvation model based on solute electron density called SMD for aqueous solutions. Despite neglecting relativistic and spin orbit effects the agreement of the calculated ?(195)Pt chemical shifts with experimental values is surprising probably due to effective error compensation. Moreover, the observed solvent effects on the structural parameters of the complexes probably overcome the relativistic effects, and therefore the successful applicability of the non-relativistic GIAO-PBE0/SARC-ZORA(Pt)?6-31+G(d)(E) computational protocol in producing reliable ?(calcd)((195)Pt) chemical shifts could be understood. In a few cases (e.g. the dihydroxo Pt(IV) complexes) the higher deviations of the calculated from the experimental values of ?(195)Pt chemical shifts are probably due to the fact that the experimental assignments refer to a different composition of the complexes in solutions than that used in the calculations, and different hydrogen bonding and formation of dimeric species. PMID:24519094

Tsipis, Athanassios C; Karapetsas, Ioannis N

2014-04-14

314

Application of soft X-ray absorption spectroscopy in chemical characterization of antiwear films generated by ZDDP Part II: the effect of detergents and dispersants  

Microsoft Academic Search

X-ray absorption near edge structure (XANES) spectroscopy has been used to study the chemical nature of the antiwear films generated on steel surfaces using zinc dialkyldithiophosphates (ZDDPs), in the presence of detergents and dispersants. The spectra were recorded both in total electron yield (TEY) and fluorescence yield (FY) modes, to investigate the chemical nature of P,S, Ca and O on

Zhanfeng Yin; M. Kasrai; G. M. Bancroft; K. Fyfe; M. L. Colaianni; K. H. Tan

1997-01-01

315

Collective instabilities  

SciTech Connect

The lecture covers mainly Sections 2.VIII and 3.VII of the book ''Accelerator Physics'' by S.Y. Lee, plus mode-coupling instabilities and chromaticity-driven head-tail instability. Besides giving more detailed derivation of many equations, simple interpretations of many collective instabilities are included with the intention that the phenomena can be understood more easily without going into too much mathematics. The notations of Lee's book as well as the e{sup jwt} convention are followed.

K.Y. Ng

2003-08-25

316

Collective Electrodynamics  

NASA Astrophysics Data System (ADS)

In this book Carver Mead offers a radically new approach to the standard problems of electromagnetic theory. Motivated by the belief that the goal of scientific research should be the simplification and unification of knowledge, he describes a new way of doing electrodynamics--collective electrodynamics--that does not rely on Maxwell's equations, but rather uses the quantum nature of matter as its sole basis. Collective electrodynamics is a way of looking at how electrons interact, based on experiments that tell us about the electrons directly. (As Mead points out, Maxwell had no access to these experiments.) The results Mead derives for standard electromagnetic problems are identical to those found in any text. Collective electrodynamics reveals, however, that quantities that we usually think of as being very different are, in fact, the same--that electromagnetic phenomena are simple and direct manifestations of quantum phenomena. Mead views his approach as a first step toward reformulating quantum concepts in a clear and comprehensible manner. The book is divided into five sections: magnetic interaction of steady currents, propagating waves, electromagnetic energy, radiation in free space, and electromagnetic interaction of atoms. In an engaging preface, Mead tells how his approach to electromagnetic theory was inspired by his interaction with Richard Feynman. Carver A. Mead is the Gordon and Betty Moore Professor of Engineering and Applied Science, Emeritus, at the California Institute of Technology. He won the 1999 Lemelson-MIT Prize for Invention and Innovation.

Mead, Carver A.

2002-08-01

317

Chemical and Physical Changes  

NSDL National Science Digital Library

The phenomenon is a chemical reaction between sugar and sulfuric acid. The demonstration (a discrepant event) compares the way sugar and water interact when combined (physical change) to the way sugar and sulfuric acid interact when combined (chemical change). In part II, students are given additional substances and changes to observe.

318

Development of a specific and highly sensitive optical chemical sensor for determination of Hg(II) based on a new synthesized ionophore.  

PubMed

A novel optode for determination of Hg(II) ions is developed based on immobilization of a recently synthesized ionophore, 7-(1H-imidazol-1-ylmethyl)-5,6,7,8,9,10-hexahydro-2H-1,13,4,7,10 benzodioxatriaza cyclopentadecine-3,11(4H,12H)-dione, in a PVC membrane. Dioctyl sebacate was used as a plasticizer, sodium tetraphenylborate as an anionic additive and ETH5294 as a chromoionophore. The response of the optode was based on the complexation of Hg(II) with the ionophore in the membrane phase, resulting an ion exchange process between Hg(II) in the sample solution and H(+) in the membrane. The effects of pH and amounts of the ionophore, chromoionophore, ionic additive and type of plasticizer on the optode response were investigated. The selectivity of the optode was studied in the present of several cations. The optode has a linear response to Hg(II) in the range of 7.2×10(-13)-4.7×10(-4) mol L(-1) with detection limit of 0.18 pmol L(-1). The optode was successfully applied to the determination of Hg(II) in real samples. PMID:23910329

Firooz, Ali R; Ensafi, Ali A; Karimi, K; Sharghi, H

2013-10-01

319

Structures of the I-, II- and H-methane clathrates and the ice-methane clathrate phase transition from quantum-chemical modeling with force-field thermal corrections.  

PubMed

Methane hydrates with the three clathrate structures I, II, and H are studied by quantum-chemical methods. Hybrid density-functional theory B3LYP computations using periodic boundary conditions are combined with force-field methods for the thermal energy effects to calculate energetic, thermodynamic, and structural properties. The pressure dependencies for the crystal structures, lattice energies, and guest molecule interactions are derived. The quantum-chemical geometry optimizations predict too small cell volumes as compared to experimental data, but by including zero-point energy and thermal energy effects, we find the cell volumes increase and the correct densities are obtained. The phase transition from MH-I to ice Ih and methane was computed and found to occur at about 9.7 MPa. PMID:21341763

Lenz, Annika; Ojamäe, Lars

2011-06-16

320

Development of quantitative structure-activity relationship (QSAR) models to predict the carcinogenic potency of chemicals. II. Using oral slope factor as a measure of carcinogenic potency.  

PubMed

The overall risk associated with exposure to a chemical is determined by combining quantitative estimates of exposure to the chemical with their known health effects. For chemicals that cause carcinogenicity, oral slope factors (OSFs) and inhalation unit risks are used to quantitatively estimate the carcinogenic potency or the risk associated with exposure to the chemical by oral or inhalation route, respectively. Frequently, there is a lack of animal or human studies in the literature to determine OSFs. This study aims to circumvent this problem by developing quantitative structure-activity relationship (QSAR) models to predict the OSFs of chemicals. The OSFs of 70 chemicals based on male/female human, rat, and mouse bioassay data were obtained from the United States Environmental Protection Agency's Integrated Risk Information System (IRIS) database. A global QSAR model that considered all 70 chemicals as well as species and/or sex-specific QSARs were developed in this study. Study results indicate that the species and sex-specific QSARs (r(2)>0.8, q(2)>0.7) had a better predictive abilities than the global QSAR developed using data from all species and sexes (r(2)=0.77, q(2)=0.73). The QSARs developed in this study were externally validated, and demonstrated reasonable predictive abilities. PMID:20951756

Wang, Nina Ching Yi; Venkatapathy, Raghuraman; Bruce, Robert Mark; Moudgal, Chandrika

2011-03-01

321

Chemicals identified in feral and food animals: a data base. Volume II. Records 533-1515. Second annual report, October 1982  

SciTech Connect

A comprehensive data base of chemicals identified in feral and food animals has been established. This effort has grown out of the concern over continuing reports of toxic chemicals in human tissues and body fluids. Feral populations and food animals are regarded as indicators of environmental contamination and subsequent human body burden. This data file is a companion to Chemicals Identified in Human Biological Media, A Data Base, and follows basically the same format. Data were obtained primarily from the open literature through manual searches (retrospective to 1979). The data base contains information on 134 different substances.

Cone, M.V.; Faust, R.A.; Baldauf, M.F. (comps.)

1982-12-01

322

Workshop on Selection, Operation and Maintenance of Process and Chemical Pumps Held on February 13-15, 1980. Volume II: Technical Papers.  

National Technical Information Service (NTIS)

One of the technologically important and fast developing areas of the Indian pump industry is the manufacture of chemical and process pumps. In order to bring about a good rapport amongst the manufacturers, users and consultants, this workshop was organiz...

1980-01-01

323

Responses of the L5178Y tk/sup +//tk/sup -/ mouse lymphoma cell forward mutation assay. II. 18 coded chemicals  

SciTech Connect

Eighteen chemicals were tested for their mutagenic potential in the L5178Y tk/sup +///sup -/ mouse lymphoma cell forward mutation assay by the use of procedures based upon those described previously. Cultures were exposed to the chemicals for 4 hr, then cultured for 2 days before plating in soft agar with or without trifluorothymidine (TFT), 3 ..mu..g/ml. The chemicals were tested at least twice. Significant responses were obtained with benzofuran, benzyl chloride, bromodichloromethane, butylated hydroxytoluene, chlorendic acid, o-chlorobenzalmalonitrile, 1,2,3,4-diepoxybutane, dimethyl formamide, dimethyl hydrogen phosphite, furfural, glutaraldehyde, hydroquinone, 8-hydroxyquinoline, and resorcinol. Apart from bromodichloromethane, butylated hydroxytoluene and dimethyl hydrogen phosphite, rat liver S9 mix was not a requirement for the activity of any of these compounds. Chemicals not identified as mutagens were water, tert-butyl alcohol, pyridine, and witch hazel.

McGregor, D.B.; Brown, A.; Cattanach, P.; Edwards, I.; McBride, D.; Caspary, W.J.

1988-01-01

324

Pamphlet Collection  

NSDL National Science Digital Library

In a welcome move to researchers and historians, the British Library of Political and Economic Science (BLPES) has created an online guide to its large pamphlet collection, containing some 90,000 pamphlets, many from the 19th and early 20th centuries. While covering a number of important public and political issues in British history, the collection also contains a fair amount of European and International materials, including a large number of German-language pamphlets, as well as materials on Latin American trade unions, the League of Nations, pacifism, the two World Wars, and conflict in the Middle East. Users can browse the guide by fifteen topics (e.g., Issues in British history, political parties, social policy, poor laws, transport, etc.) or search the online catalog by subject keyword, author, title, or issuing body. The guide lists pamphlet author, title, and classmark, while the online catalog also includes publisher, pages, location, and other notes. As an added bonus, the majority of pamphlets listed in the social policy and transport guides have been digitized and are available in .pdf format.

325

Chemical kinetic model for NO(sub x) removal in an aqueous scrubber system using the additive Fe(II)(center dot)EDTA.  

National Technical Information Service (NTIS)

Addition of the metal chelate, ferrous(center dot) ethylenediaminetetraacetate anion (Fe(II)(center dot)EDTA(sup 2(minus))), has been shown to increase the amount of gaseous nitrogen oxides absorbed from a gas stream containing sulfur dioxide, where an aq...

M. H. Mendelsohn C. D. Livengood

1992-01-01

326

The LIFE Picture Collection  

NSDL National Science Digital Library

Although this is a commercial site with pictures and images for sale, users can nonetheless view and appreciate one of "the most extraordinary collections of pictures in the world" at The Picture Collection from Time, Inc. An initial free registration is required, and after that users need only log on to gain access to over 22 million images, including illustrations, prints, and photographs. Archival materials from many popular magazines are available here, including images from Time, Life, Sports Illustrated, People, and Entertainment Weekly, as well as material from the recently acquired Mansell Collection. "Mansell photographs date from the beginnings of the medium in the 1840s through World War II [and] depict a vast range of scenics, important news events, and historical personalities, with a special emphasis on art and architecture. In addition, the new Mansell Collection includes extraordinary holdings of engraved illustrations, lithographs, and drawings predating the advent of photographic imaging." In addition to a key word search function, The Picture Collection offers a special searching and licensing program that lets you search for and store materials in "Lightboxes" of your own creation for later use; these are similar to folders that one might use in a conventional software setting. The program also calculates licensing fees for images based on what type of usage is intended (newspaper, magazine, Website, etc.). Research help is available for those users who would like someone else to do the searching, with one half-hour of free research offered initially. After that, a fee of 85 dollars an hour is charged; some or all of this fee may be waived if one or more images are licensed. An excellent help section rounds out this site and makes perusing this amazing (if somewhat overwhelming) collection even more pleasurable.

327

Hemingway Collection  

NSDL National Science Digital Library

Ernest Hemingway was a red-blooded man of letters, and one of the 20th century's most celebrated and demonized writers. In 1968, Mary Hemingway arranged to have his papers donated to the Kennedy Library. Over the past several decades, materials related to Hemingway's long career have continued to become part of this very extensive collection. The Kennedy Library has created this specific page to provide both researchers and members of the general public with some basic information about their holdings, along with offering access to a selection of these papers. The photograph galleries are a real treat, as they cover everything from Hemingway's youth in Oak Park all the way up to his last days in Idaho.

328

Health effects in Army Gulf War veterans possibly exposed to chemical munitions destruction at Khamisiyah, Iraq: Part II. Morbidity associated with notification of potential exposure.  

PubMed

The purpose of this study was to examine the association of notification of potential exposure to chemical warfare agents in the 1991 Gulf War with subsequent self-reported morbidity. The study sample included 1,056 deployed Army Gulf War veterans who responded to the 1995 National Health Survey of Gulf War Era Veterans and who were resurveyed in 2000. One-half of the subjects had been notified of potential exposure to chemical warfare agents and one-half had not. Comparing notified and non-notified subjects, there were no statistically significant differences with respect to bed days, activity limitations, clinic visits, or hospital visits. Among 71 self-reported medical conditions and symptoms, there were 5 statistically significant differences, 4 of which were for lower rates of illness among notified subjects. Our findings contradict the prevailing notion that perceived exposure to chemical warfare agents should be considered an important cause of morbidity among Gulf War veterans. PMID:16450822

Page, William F; Mahan, Clare M; Kang, Han K; Bullman, Tim A

2005-11-01

329

Comprehensive investigation of the corrosion state of the heat exchanger tubes of steam generators. Part II. Chemical composition and structure of tube surfaces  

NASA Astrophysics Data System (ADS)

In the frame of a project dealing with the comprehensive study of the corrosion state of the steam generators of the Paks Nuclear Power Plant, Hungary, surface properties (chemical and phase compositions) of the heat exchanger tubes supplied by the power plant were studied by Mössbauer spectroscopy (CEMS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) methods. The work presented in this series provides evidence that chemical decontamination of the steam generators by the AP-CITROX technology does exert a detrimental effect on the chemical composition and structure of the protective oxide film grown-on the inner surfaces of heat exchanger piping. As an undesired consequence of the decontamination technology, a 'hybrid' structure of the amorphous and crystalline phases is formed in the outermost surface region (within a range of 11 ?m). The constituents of this 'hybrid' structure exhibit great mobility into the primary coolant under normal operation of the VVER type reactor.

Homonnay, Z.; Kuzmann, E.; Varga, K.; Németh, Z.; Szabó, A.; Radó, K.; Makó, K. É.; Kövér, L.; Cserny, I.; Varga, D.; Tóth, J.; Schunk, J.; Tilky, P.; Patek, G.

2006-01-01

330

Terrorism and Security Collection  

NSDL National Science Digital Library

The National Academies Press (NAP) offers the full text of several publications related to bioterrorism, laboratory safety, and cryptography, among other topics, for browsing online. Although not all of the titles are new, NAP has collected them on one page for easy access in light of current events. The 26 titles include Airline Passenger Security Screening: New Technologies and Implementation Issues (1996), Chemical and Biological Terrorism: Research and Development to Improve Civilian Medical Response (1999), Firepower in the Lab: Automation in the Fight Against Infectious Diseases and Bioterrorism (2001), Improving Civilian Medical Response to Chemical or Biological Terrorist Incidents: Interim Report on Current Capabilities (1998), Improved Fire- and Smoke-Resistant Materials for Commercial Aircraft Interiors: Proceedings (1995) and Black and Smokeless Powders: Technologies for Finding Bombs and the Bomb Makers (1998). Users can perform keyword searches within each publication.

2001-01-01

331

75 FR 65673 - Notice of Information Collection  

Federal Register 2010, 2011, 2012, 2013

...SUPPLEMENTARY INFORMATION: I. Abstract The purpose of this survey is to assimilate lunar regolith stimulant requirements as well as Apollo sample requests for the ETDP and Constellation projects and test facilities. II. Method of Collection Electronic. III....

2010-10-26

332

75 FR 53349 - Notice of Information Collection  

Federal Register 2010, 2011, 2012, 2013

...SUPPLEMENTARY INFORMATION: I. Abstract: The purpose of this survey is to assimilate lunar regolith stimulant requirements as well as Apollo sample requests for the ETDP and Constellation projects and test facilities. II. Method of Collection Electronic. III....

2010-08-31

333

78 FR 52215 - Notice of Information Collection  

Federal Register 2010, 2011, 2012, 2013

...operations. II. Method of Collection The current, paper-based reporting system ensures the protection of a submitters anonymity and secure submission of the report by way of the U.S. Postal Service. III. Data Title: NASA Safety Reporting...

2013-08-22

334

78 FR 34675 - Notice of Information Collection  

Federal Register 2010, 2011, 2012, 2013

...operations. II. Method of Collection The current, paper-based reporting system ensures the protection of a submitters anonymity and secure submission of the report by way of the U.S. Postal Service. III. Data Title: NASA Safety Reporting...

2013-06-10

335

77 FR 69659 - Notice of Information Collection  

Federal Register 2010, 2011, 2012, 2013

...operations. II. Method of Collection The current, paper-based reporting system ensures the protection of a submitters anonymity and secure submission of the report by way of the U.S. Postal Service. III. Data Title: NASA Safety Reporting...

2012-11-20

336

Evaluation of the National School Lunch Program Application/Verification Pilot Projects: Volume II: Data Collection, Study Methods and Supplementary Tables on Certification Impacts. Nutrition Assistance Program Report Series. Report No. CN-04-AV2  

ERIC Educational Resources Information Center

This is Volume II of the report on the evaluation of the NSLP Application Verification Pilot Projects. It supplements Volume I, which presents the evaluation findings. Volume II has two objectives: (1) to provide a detailed description of the methods used to conduct the study; and (2) to present tabulations that supplement and extend the analyses…

Burghardt, John; Gleason, Philip; Sinclair, Michael; Cohen, Rhoda; Hulsey, Lara; Milliner-Waddell, Julita

2004-01-01

337

Comprehensive investigation of the corrosion state of the heat exchanger tubes of steam generators. Part II. Chemical composition and structure of tube surfaces  

Microsoft Academic Search

In the frame of a project dealing with the comprehensive study of the corrosion state of the steam generators of the Paks Nuclear Power Plant, Hungary, surface properties (chemical and phase compositions) of the heat exchanger tubes supplied by the power plant were studied by Mössbauer spectroscopy (CEMS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) methods. The work presented

Z. Homonnay; E. Kuzmann; K. Varga; Z. Németh; A. Szabó; K. Radó; K. É. Makó; L. Kövér; I. Cserny; D. Varga; J. Tóth; J. Schunk; P. Tilky; G. Patek

2006-01-01

338

A comprehensive model for reproductive and developmental toxicity hazard identification: II. Construction of QSAR models to predict activities of untested chemicals  

Microsoft Academic Search

This report describes the construction, optimization and validation of a battery of quantitative structure–activity relationship (QSAR) models to predict reproductive and developmental (reprotox) hazards of untested chemicals. These models run with MC4PC software to predict seven general reprotox classes: male and female reproductive toxicity, fetal dysmorphogenesis, functional toxicity, mortality, growth, and newborn behavioral toxicity. The reprotox QSARs incorporate a weight

Edwin J. Matthews; Naomi L. Kruhlak; R. Daniel Benz; Julian Ivanov; Gilles Klopman; Joseph F. Contrera

2007-01-01

339

Physicochemical applications of liquid chromatography II. Investigations of the surface properties of chemically modified silica gels and of the adsorption of cardiac glycosides from solutions  

Microsoft Academic Search

The chemical modification of silica surface using dichlorosilanes with methyl and phenyl groups and triethylamine as donor in the liquid phase was investigated. This modification leads to a dense coverage of the silica surface by the organic functional groups. Liquid chromatography permits the determination of the thermodinamic characteristics of intermolecular interactions of different molecules during adsorption from solutions on the

V. Ya. Davydov; M. Elizalde Gonzalez; A. V. Kiselev; K. Lenda

1981-01-01

340

THE MOST METAL-POOR STARS. II. CHEMICAL ABUNDANCES OF 190 METAL-POOR STARS INCLUDING 10 NEW STARS WITH [Fe/H] {<=} -3.5 , ,  

SciTech Connect

We present a homogeneous chemical abundance analysis of 16 elements in 190 metal-poor Galactic halo stars (38 program and 152 literature objects). The sample includes 171 stars with [Fe/H] {<=} -2.5, of which 86 are extremely metal poor, [Fe/H] {<=} -3.0. Our program stars include 10 new objects with [Fe/H] {<=} -3.5. We identify a sample of 'normal' metal-poor stars and measure the trends between [X/Fe] and [Fe/H], as well as the dispersion about the mean trend for this sample. Using this mean trend, we identify objects that are chemically peculiar relative to 'normal' stars at the same metallicity. These chemically unusual stars include CEMP-no objects, one star with high [Si/Fe], another with high [Ba/Sr], and one with unusually low [X/Fe] for all elements heavier than Na. The Sr and Ba abundances indicate that there may be two nucleosynthetic processes at lowest metallicity that are distinct from the main r-process. Finally, for many elements, we find a significant trend between [X/Fe] versus T {sub eff}, which likely reflects non-LTE and/or three-dimensional effects. Such trends demonstrate that care must be exercised when using abundance measurements in metal-poor stars to constrain chemical evolution and/or nucleosynthesis predictions.

Yong, David; Norris, John E.; Bessell, M. S.; Asplund, M. [Research School of Astronomy and Astrophysics, The Australian National University, Weston, ACT 2611 (Australia)] [Research School of Astronomy and Astrophysics, The Australian National University, Weston, ACT 2611 (Australia); Christlieb, N. [Zentrum fuer Astronomie der Universitaet Heidelberg, Landessternwarte, Koenigstuhl 12, D-69117 Heidelberg (Germany)] [Zentrum fuer Astronomie der Universitaet Heidelberg, Landessternwarte, Koenigstuhl 12, D-69117 Heidelberg (Germany); Beers, Timothy C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States)] [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Barklem, P. S. [Department of Physics and Astronomy, Uppsala University, Box 515, SE-75120 Uppsala (Sweden)] [Department of Physics and Astronomy, Uppsala University, Box 515, SE-75120 Uppsala (Sweden); Frebel, Anna [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States)] [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States); Ryan, S. G., E-mail: yong@mso.anu.edu.au, E-mail: jen@mso.anu.edu.au, E-mail: bessell@mso.anu.edu.au, E-mail: martin@mso.anu.edu.au, E-mail: n.christlieb@lsw.uni-heidelberg.de, E-mail: beers@pa.msu.edu, E-mail: paul.barklem@physics.uu.se, E-mail: afrebel@mit.edu, E-mail: s.g.ryan@herts.ac.uk [Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield, Hertfordshire AL10 9AB (United Kingdom)

2013-01-01

341

A Study of the Economics and Environmental Viability of a U.S. Flag Toxic Chemical Incinerator Ship. Volume II: Detailed Study.  

National Technical Information Service (NTIS)

This report details the economic and environmental viability of incinerating toxic chemical wastes at sea using a U.S. flag ship(s). The ocean incineration history in Europe and the United States is reviewed first. The impact of international, national, a...

M. Halebsky

1978-01-01

342

Retrospective mortality study of workers in three major U. S. refineries and chemical plants. Part II: Internal comparisons by geographic site, occupation, and smoking history  

Microsoft Academic Search

A cohort of 21,698 U.S. refinery and chemical plant workers was observed for eight years to determine if there were interplant or other variations in causes of mortality. Plant populations in three geographic locations were combined to develop an internal standard for comparing subgroups within the total cohort. At no one geographic site were consistently different rates for all major

Nancy M. Hanis; Leba G. Shallenberger; Donna L. Donaleski; Eugene A. Sales

1985-01-01

343

Chemical cytometry on a picoliter-scale integrated microfluidic chip  

NASA Astrophysics Data System (ADS)

An integrated microfluidic device has been fabricated for analyzing the chemical contents of a single cell (chemical cytometry). The device is designed to accomplish four different functions: (i) cell handling, (ii) metering and delivering of chemical reagents, (iii) cell lysis and chemical derivatization, and (iv) separating derivatized compounds and detecting them by laser-induced fluorescence. These functions are accomplished with only two valves, formed by multilayer soft lithography. A new kind of three-state valve and a picopipette are described; these elements are crucial for minimizing the reaction volume and ensuring optimal shape of the channel for electrophoresis injection. By using these valves, a reaction volume of 70 pl is achieved for the lysis and derivitization of the contents of a single Jurkat T cell (10 µm diameter). As a demonstration of the use of this integrated microfluidic device, electropherograms of amino acids from individual Jurkat T cells are recorded and compared with those collected from a multiple-cell homogenate.

Wu, Hongkai; Wheeler, Aaron; Zare, Richard N.

2004-08-01

344

Chemical Principles Exemplified  

ERIC Educational Resources Information Center

Collection of two short descriptions of chemical principles seen in life situations: the autocatalytic reaction seen in the bombardier beetle, and molecular potential energy used for quick roasting of beef. Brief reference is also made to methanol lighters. (PS)

Plumb, Robert C.

1972-01-01

345

Mary Louise Reynolds Collection  

NSDL National Science Digital Library

Mary Louise Reynolds (1891-1950) led a fascinating life at the center of the Surrealist circle of artists, numbering as her friends Max Ernst, Man Ray, Paul ÃÂluard, André Breton, Jean Cocteau, and Salvador Dalí. Reynolds and Surrealist Marcel Duchamp were partners in a long term relationship thought by their friends to be far happier than most marriages. She was a book artist and served in the French resistance during World War II. The materials in the Mary Louise Reynolds Archive and her collection of rare books and bindings at the Art Institute of Chicago have inspired at least two books and several exhibitions, as well as this Web site. The site features four essays reprinted from the Art Institute's Museum Studies journal, illustrated with digital images of Surrealist works, and available in both HTML and Adobe Acrobat (.pdf) formats. There is also an online finding aid to the collection, and it is possible to search the Ryerson and Burnham Library's catalog for Reynolds collection items. One portion of the site (View Works of Art) brings together all the digitized works of art: Reynolds' book bindings, Surrealist documents, prints, and a few photographs.

346

University of Wisconsin Digital Collections: The Science Collection  

NSDL National Science Digital Library

The Science Collection brings together writings about scientific research conducted by University of Wisconsin faculty and staff; and unique or valuable items related to science held by the University of Wisconsin Libraries. Subcollections include a Botany Department Teaching Collection (images), an electronic edition of Thermophilic Microorganisms and Life at High Temperatures (1978) by Thomas D. Brock, a collection of veterinary anatomical illustrations derived from the Handbuch der Anatomie der Tiere fur Kunstler, or Handbook of Animal Anatomy for Artists (1898, 1911-1925) and the Journal of Chemical Education.

Center, University O.

347

Magnetic and optical properties of Cu(II)-bis(oxamato) complexes: combined quantum chemical density functional theory and vibrational spectroscopy studies.  

PubMed

Vibrational spectroscopies are shown to be highly sensitive to the structural modifications of paramagnetic mono- and trinuclear Cu(II)-bis(oxamato) complexes. The vibrational bands are assigned using density functional theory (DFT) calculations. Moreover, Raman spectroscopy investigations for different temperatures of thin films show that the onset of superexchange interactions at low temperatures does not involve a modification of the structural parameters. The influence of packing effects, however, on the magnetic properties is significant, as demonstrated by means of DFT using the broken symmetry approach. PMID:18410161

Bräuer, Björn; Weigend, Florian; Totti, Federico; Zahn, Dietrich R T; Rüffer, Tobias; Salvan, Georgeta

2008-05-01

348

Chemical vapor infiltration of pyrocarbon —II. The influence of increasing methane partial pressure at constant total pressure on infiltration rate and degree of pore filling  

Microsoft Academic Search

Chemical vapor infiltration of pyrocarbon with methane as the carbon source was studied at a total pressure of 20 kPa, a temperature of 1100 °C and methane partial pressures from 2.5 to 20 kPa. A cylindrically-shaped porous alumina ceramic, 20 mm in height and 16 mm in diameter, was used as the substrate. The pore entrance diameters of the porous

W. Benzinger; K. J. Hüttinger

1998-01-01

349

Microalgae for use in tropical aquaculture II: Effect of salinity on growth, gross chemical composition and fatty acid composition of three species of marine microalgae  

Microsoft Academic Search

The influence of salinity on the growth, gross chemical composition and fatty acid composition of three species of marine microalgae,Isochrysis sp.,Nannochloropsis oculata andNitzschia (frustulum), was investigated. There was no significant change in growth rate ofIsochrysis sp. andN. (frustulum) over the experimental range of salinity (10–35 ppt), whileN. oculata had a significantly slower growth rate only at 35 ppt. The ash

S. M. Renaud; D. L. Parry

1994-01-01

350

Miniature free-piston homogeneous charge compression ignition engine-compressor concept—Part II: modeling HCCI combustion in small scales with detailed homogeneous gas phase chemical kinetics  

Microsoft Academic Search

Operational maps for crankshaft-equipped miniature homogeneous charge compression ignition engines are established using performance estimation, detailed chemical kinetics, and diffusion models for heat transfer and radical loss. In this study, radical loss was found to be insignificant. In contrast, heat transfer was found to be increasingly significant for 10, 1, and 0.1W engines, respectively. Also, temperature–pressure trajectories and ignition delay

H. T. Aichlmayr; D. B. Kittelson; M. R. Zachariah

2002-01-01

351

Case study II: application of the divalent cation bridging theory to improve biofloc properties and industrial activated sludge system performance-using alternatives to sodium-based chemicals.  

PubMed

The objective of this study was to investigate the application of the divalent cation bridging theory (DCBT) as a tool in the chemical selection process at an activated sludge plant to improve settling, dewatering, and effluent quality. According to the DCBT, to achieve improvements, the goal of chemical selection should be to reduce the ratio of monovalent-to-divalent (M/D) cations. A study was conducted to determine the effect of using magnesium hydroxide [Mg(OH)2] as an alternative to sodium hydroxide (NaOH) at a full-scale industrial wastewater treatment plant. Floc properties and treatment plant performance were measured for approximately one year during two periods of NaOH addition and Mg(OH)2 addition. A cost analysis of plant operation during NaOH and Mg(OH)2 use was also performed. During NaOH addition, the M/D ratio was 48, while, during Mg(OH)2 addition, this ratio was reduced to an average of approximately 0.1. During the Mg(OH)2 addition period, the sludge volume index, effluent total suspended solids, and effluent chemical oxygen demand were reduced by approximately 63, 31, and 50%, respectively, compared to the NaOH addition period. The alum and polymer dose used for clarification was reduced by approximately 50 and 60%, respectively, during Mg(OH)2 addition. The dewatering properties of the activated sludge improved dewatering as measured by decreased capillary suction time and specific resistance to filtration (SRF), along with an increase in cake solids from the SRF test. This corresponded to a reduction in the volume of solids thickened by centrifuges at the treatment plant, which reduced the disposal costs of solids. Considering the costs for chemicals and solids disposal, the annual cost of using Mg(OH)2 was approximately 30,000 dollars to 115,000 dollars less than using NaOH, depending on the pricing of NaOH. The results of this study confirm that the DCBT is a useful tool for assessing chemical-addition strategies and their potential effect on activated sludge performance. PMID:15508426

Higgins, Matthew J; Sobeck, David C; Owens, Steven J; Szabo, Lynn M

2004-01-01

352

CHEMICAL ABUNDANCES OF THE MILKY WAY THICK DISK AND STELLAR HALO. II. SODIUM, IRON-PEAK, AND NEUTRON-CAPTURE ELEMENTS  

SciTech Connect

We present chemical abundance analyses of sodium, iron-peak, and neutron-capture elements for 97 kinematically selected thick disk, inner halo, and outer halo stars with metallicities -3.3 < [Fe/H] <-0.5. The main aim of this study is to examine chemical similarities and differences among metal-poor stars belonging to these old Galactic components as a clue to determine their early chemodynamical evolution. In our previous paper, we obtained abundances of {alpha} elements by performing a one-dimensional LTE abundance analysis based on the high-resolution (R {approx} 50, 000) spectra obtained with the Subaru/HDS. In this paper, a similar analysis is performed to determine abundances of an additional 17 elements. We show that, in metallicities below [Fe/H] {approx}-2, the abundance ratios of many elements in the thick disk, inner halo, and outer halo subsamples are largely similar. In contrast, in higher metallicities ([Fe/H] {approx}> -1.5), differences in some of the abundance ratios among the three subsamples are identified. Specifically, the [Na/Fe], [Ni/Fe], [Cu/Fe], and [Zn/Fe] ratios in the inner and outer halo subsamples are found to be lower than those in the thick disk subsample. A modest abundance difference between the two halo subsamples in this metallicity range is also seen for the [Na/Fe] and [Zn/Fe] ratios. In contrast to that observed for [Mg/Fe] in our previous paper, [Eu/Fe] ratios are more enhanced in the two halo subsamples rather than in the thick disk subsample. The observed distinct chemical abundances of some elements between the thick disk and inner/outer halo subsamples with [Fe/H] >-1.5 support the hypothesis that these components formed through different mechanisms. In particular, our results favor the scenario that the inner and outer halo components formed through an assembly of multiple progenitor systems that experienced various degrees of chemical enrichments, while the thick disk formed through rapid star formation with an efficient mixing of chemical elements. The lower [Na/Fe] and [Zn/Fe] observed in stars with the outer halo kinematics may further suggest that progenitors with longer star formation timescales contributed to the buildup of the relatively metal-rich part of stellar halos.

Ishigaki, M. N. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Chiba, M., E-mail: miho.ishigaki@ipmu.jp, E-mail: aoki.wako@nao.ac.jp, E-mail: chiba@astr.tohoku.ac.jp [Astronomical Institute, Tohoku University, Aoba-ku, Sendai 980-8578 (Japan)

2013-07-01

353

Chemical feedstocks from coal  

Microsoft Academic Search

In theory, coal can provide all the chemical feedstocks now derived from oil; however, coal-chemistry technology has become outdated and needs to be improved to meet today's economic and technical demands. To bridge this gap, this collection of essays (translated from German) presents the current possibilities for producing organic chemicals from coal and suggests some routes for future developmental work.

J. Falbe; E. Ahland; G. Baron

1982-01-01

354

The Margo Duggan Collection  

NSDL National Science Digital Library

Margo Duggan served in the United States Marine Corps during World War II, and after the war was over she started working as a civilian employee of the United States Trust Territories Administration in 1949. Over the next five years, she worked on a number of the Marshall, Mariana, and Caroline Islands and over at the Trust Territory headquarters in Hawai'i. She took a number of photographs during her time, and they document an important moment in the history of Micronesia. The University of Hawaii at Manoa's Library created this site, and visitors can view over 1,000 of the images she created. Curious visitors can read a brief biography of Duggan here and also look over the "About" page to learn more how the collection came to the university. The majority of the images here document life in Micronesia, and visitors can look through them via title, category, date, location, or reference number.

355

Prokudin-Gorskii Collection  

NSDL National Science Digital Library

Born in the town of Murom, Russia, Sergei Mikhailovich Prokudin-Gorskii was educated as a chemist and dedicated his life to the advancement of photography. He spent many years documenting the Russian Empire, and he was even outfitted with a railroad car-darkroom provided by Tsar Nicholas II. Along with this equipment, the Tsar also gave him access to certain restricted areas. After Prokudin-Gorskii died in 1944, his sons sold his collection of photographs, glass negatives, and sepia-tone prints to the Library of Congress in 1948. This site allows visitors to view these images, which include photographs of prominent religious structures, public works, industrial areas, and people in traditional dress. Visitors can also look over some of the thematic albums, which include his travels to Central Asia in 1911 and his journey along the Oka River south of Moscow in 1912.

356

OXALATE MASS BALANCE DURING CHEMICAL CLEANING IN TANK 6F  

SciTech Connect

The Savannah River Remediation (SRR) is preparing Tank 6F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning to determine whether the tank is ready for closure. SRR personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. Analysis of the anions showed the measured oxalate removed from Tank 6F to be approximately 50% of the amount added in the oxalic acid. To close the oxalate mass balance, the author collected solid samples, leached them with nitric acid, and measured the concentration of cations and anions in the leachate. Some conclusions from this work are: (1) Approximately 65% of the oxalate added as oxalic acid was removed with the decanted liquid. (2) Approximately 1% of the oxalate (added to the tank as oxalic acid) formed precipitates with compounds such as nickel, manganese, sodium, and iron (II), and was dissolved with nitric acid. (3) As much as 30% of the oxalate may have decomposed forming carbon dioxide. The balance does not fully account for all the oxalate added. The offset represents the combined uncertainty in the analyses and sampling.

Poirier, M.; Fink, S.

2011-07-22

357

A family of novel macrocyclic lactones, the saccharocarcins produced by Saccharothrix aerocolonigenes subsp. antibiotica. II. Physico-chemical properties and structure determination.  

PubMed

Six novel tetronic acid analogs were isolated from the fermentation broth of the actinomycete Saccharothrix aerocolongenes subsp. antibiotica SCC1886. The structures of these saccharocarcins were determined by their spectral data, and chemical degradation. All six compounds are derived from two modified tetronic acid homologs which differ from other tetronic acids by having an ethyl or propyl side chain at C-23 and a methyl group at C-16. They are all characterized by a novel sugar-amide at C-17. PMID:9099221

Hegde, V R; Patel, M G; Das, P R; Pramanik, B; Puar, M S

1997-02-01

358

Chemical modification of silica-gel with diethylenetriamine via an end-group protection approach for adsorption to Hg(II)  

NASA Astrophysics Data System (ADS)

Four kinds of silica-gel supported diethylenetriamine adsorbents with different structures, were prepared by so-called "heterogeneous-direct-amination" (hetero-DA), "homogeneous-direct-amination" (homo-DA), "heterogeneous end-group protection" (hetero-EGP), and "homogeneous end-group protection" (homo-EGP) methods, respectively. The obtained products were named SG-HE-dD, SG-HO-dD, SG-HE-pD and SG-HO-pD, respectively (where SG means silica-gel; HE means heterogeneous, HO means homogeneous, d means direct, p means protected and D means diethylenetriamine). Their structures were characterized by FT-IR, elemental analysis, porous structure analysis and thermogravimetric analysis. The adsorption capabilities of such adsorbents towards Hg(II) were studied and evaluated by static method. SG-HE-pD and SG-HO-pD showed higher performance towards Hg(II) adsorption than corresponding counterparts SG-HE-dD and SG-HO-dD, even though the former two possessed lower contents of diethylenetriamine (DETA). The kinetics data indicated that the adsorption process was governed by the film diffusion and followed pseudo-first-order rate model for SG-HE-dD, SG-HO-dD and SG-HE-pD and pseudo-second-order model for SG-HO-pD. The Langmuir model was applied to fit the experimental equilibrium data for all adsorbents. The end-group protection method exhibited its advantage in preparation of effective adsorbent for metal ions uptake compared to the direct-amination method.

Zhang, Ying; Qu, Rongjun; Sun, Changmei; Wang, Chunhua; Ji, Chunnuan; Chen, Hou; Yin, Ping

2009-03-01

359

Assimilate unloading from maize (Zea mays L. ) pedicel tissues. II. Effects of chemical agents on sugar, amino acid, and /sup 14/C-assimilate unloading  

SciTech Connect

Sugar, amino acid, and /sup 14/C-assimilate release from attached maize (Zea mays L.) pedicels was studied following treatment with several chemical inhibitors. In the absence of these agents, sugar release was nearly linear over a 7-hour period. At least 13 amino acids were released with glutamine comprising over 30% of the total. Release was not affected by potassium concentration, 10-minute pretreatments with p-chloromercuribenzene sulfonic acid (PCMBS) or dithiothreitol, and low concentrations of CaCl/sub 2/. Three hours or more exposure to PCMBS, dinitrophenol, N-ethylmaleimide, or 2,4,6-trinitrobenzene sulfonic acid strongly inhibited /sup 14/C-assimilate, sugar, and amino acid release from the pedicel. These treatments also reduced /sup 14/C-assimilate movement into the kernel bases. It is, therefore, likely that reduced unloading, caused by these relatively long-term exposures to chemical inhibitors, was related to reduced translocation of assimilates into treated kernels. Whether this effect is due to disruption of kernel metabolism and sieve element function or reduced assimilate unloading and subsequent accumulation of unlabeled assimilates within the pedicel tissues cannot be determined at this time.

Porter, G.A.; Knievel, D.P.; Shannon, J.C.

1987-10-01

360

Workforce Competitiveness Collection. "LINCS" Resource Collection News  

ERIC Educational Resources Information Center

This edition of "'LINCS' Resource Collection News" features the Workforce Competitiveness Collection, covering the topics of workforce education, English language acquisition, and technology. Each month Collections News features one of the three "LINCS" (Literacy Information and Communication System) Resource Collections--Basic Skills, Program…

Literacy Information and Communication System, 2011

2011-01-01

361

Program Management Collection. "LINCS" Resource Collection News  

ERIC Educational Resources Information Center

This edition of "'LINCS' Resource Collection News" features the Program Management Collection, which covers the topics of Assessment, Learning Disabilities, and Program Improvement. Each month Collections News features one of the three "LINCS" (Literacy Information and Communication System) Resource Collections--Basic Skills, Program Management,…

Literacy Information and Communication System, 2011

2011-01-01

362

Chemical Equilibrium and Critical Phenomena: The Solubilities of Iron(III) Oxide and Cobalt(II,III) Oxide in Isobutyric Acid + Water Near the Consolute Point  

NASA Astrophysics Data System (ADS)

The solubilities of iron(III) oxide, formula Fe2O3, and cobalt(II,III) oxide, formula Co3O4, have been determined in the liquid mixture, isobutyric acid + water, along the critical isopleth at temperatures above the upper critical solution temperature near 299 K. When plotted in van’t Hoff form with ln s versus 1/ T, the measurements of solubility, s, lie on a straight line for values of the temperature, T, in kelvin, which are sufficiently in excess of the critical solution temperature, T c. The sign of the slope, (? ln s/?(1/ T)), indicates that in the case of both oxides, the dissolution reaction is endothermic. When the temperature is within 1K of T c, however, the slope departs from its constant value and appears to diverge toward negative infinity. The principle of critical-point universality predicts that a divergence in (? ln s/?(1/ T)) is to be expected for T near T c in those cases where the stoichiometry of the dissolution reaction involves both components of the solvent; moreover, the Gibbs-Helmholtz equation predicts that, if the heat of solution is endothermic, the sign of the divergence should be negative. Both of these predictions are confirmed by the solubilities of Fe2O3 and Co3O4 measured as a function of temperature along the critical isopleth of isobutyric acid + water.

Hu, Baichuan; Baird, James K.

2010-05-01

363

Observations of [S IV] 10.5 ?m and [Ne II] 12.8 ?m in Two Halo Planetary Nebulae: Implications for Chemical Self-Enrichment  

NASA Astrophysics Data System (ADS)

We have detected the [S IV] 10.5 ?m and [Ne II] 12.8 ?m fine-structure lines in the halo population planetary nebula (PN) DdDm 1 and set upper limits on their intensities in the halo PN H4-1. We also present new measurements of optical lines from various ions of S, Ne, O, and H for DdDm 1, based on a high-dispersion spectrum covering the spectral range 3800 Å to 1 ?m. These nebulae have similar O/H abundances, (O/H)~1×10-4, but S/H and Ne/H are about half an order of magnitude lower in H4-1 than in DdDm 1; thus H4-1 appears to belong to a more metal-poor population. This supports previous suggestions that PNe arising from metal-poor progenitor stars can have elevated oxygen abundances due to internal nucleosynthesis and convective dredge-up. It is generally accepted that high abundances of carbon in many PNe result from self-enrichment. To the extent that oxygen can also be affected, the use of nebular O/H values to infer the overall metallicity of a parent stellar population (for example, in external galaxies) may be suspect, particularly for low metallicities.

Dinerstein, Harriet L.; Richter, Matthew J.; Lacy, John H.; Sellgren, K.

2003-01-01

364

Chemical laser modeling with genetic algorithms  

Microsoft Academic Search

A genetic algorithm technique was implemented to determine a set of unknown parameters that best matched the Blaze II chemical laser model predictions with experimental data. This is the first known application of the genetic algorithm technique for modeling lasers, chemically reacting flows, and chemical lasers. Overall, the genetic algorithm technique worked exceptionally well for this chemical laser modeling problem

David L. Carroll

1996-01-01

365

Atmospheric Visualization Collection: Glossary  

NSDL National Science Digital Library

This page contains a glossary of terms commonly used in this collection, publications authored by collection members, scheduled meetings, and documentation on uses of the Atmospheric Visualization Collection.

Klaus, Christopher

2002-10-08

366

The origin of the moon and the early history of the earth - A chemical model. I - The moon. II - The earth  

NASA Astrophysics Data System (ADS)

Assuming that the moon was formed as a result of a giant impact by a celestial Mars-sized body with the earth, a model is developed that accounts for the chemical compositions of both the moon and the earth. The moon model assumes that about 80 percent of the moon came from the primitive earth's mantle after segregation of the earth's core and the other 20 percent came from two sources: (1) the Impactor, which is constrained to be an oxidized undifferentiated body of roughly CI chondritic composition and (2) a late-stage veneer with a composition and oxidation state similar to that of the H-group ordinary chondrites. The earth model assumes that the protoearth accreted from a material resembling a high-temperature condensate from the solar nebula. The model accounts for the siderophile element abundances of the present mantle. It predicts that neither S, O, nor Si were present in sufficient quantities to provide the required light element in the core, whose identity remains enigmatic.

O'Neill, H. St. C.

1991-04-01

367

Gas-to-particle conversion in the particle precipitation-aided chemical vapor deposition process II. Synthesis of the perovskite oxide yttrium chromite  

SciTech Connect

In the particle precipitation-aided chemical vapor deposition process, an aerosol is formed in the gas phase at elevated temperatures. The particles are deposited on a cooled substrate. Coherent layers with a controlled porosity can be obtained by a simultaneous heterogeneous reaction, which interconnects the deposited particles. The synthesis of submicrometer powder of the perovskite oxide yttrium chromite (YCrO[sub 3]) by gas to particle conversion, which is the first step of the PP-CVD process, has been investigated, and preliminary results are shown. The powders have been synthesized using yttrium trichloride vapor (YCl[sub 3]), chromium trichloride vapor (CrCl[sub 3]), and steam and oxygen as reactants. The influence of the input molar ratio of the elements on the composition and characteristics of the powders has been investigated. Phase composition has been determined by X-ray diffraction (XRD). The powders have been characterized by transmission electron microscopy (TEM) and sedimentation field flow fractionation (SF[sup 3]). At a reaction temperature of 1283 K the powders consist of the chromium sesquioxide (Cr[sub 2]O[sub 3]), or a mixture of Cr[sub 2]O[sub 3] and YCrO[sub 3]. At stoichiometeric input amounts of metal chlorides and steam the formation of YCrO[sub 3] seems to be favored. 19 refs., 6 figs., 3 tabs.

Dieten, V.E.J. van; Dekker, J.P.; Hurkmans, E.J.; Schoonman, J. (Delft Univ. of Technology (Netherlands))

1993-11-01

368

Chemical analysis of acidic silicon etch solutions II. Determination of HNO(3), HF, and H(2)SiF(6) by ion chromatography.  

PubMed

The processing of silicon in microelectronics and photovoltaics involves the isotropic chemical etching using HF-HNO(3) mixtures to clean the surface from contaminations, to remove the saw damage, as well as to polish or to texture the wafer surface. Key element of an effective etch process control is the knowledge of the actual etch bath composition in order to maintain a certain etch rate by replenishment of the consumed acids. The present paper describes a methods for the total analysis of the etch bath constituents HF, HNO(3), and H(2)SiF(6) by ion chromatography. First step is the measurement of the total fluoride and nitrate content in the analyte. In a second step, H(2)SiF(6) is precipitated as K(2)SiF(6). After careful filtration of the precipitate, the fluoride concentration in the filtrate is measured and the content of free HF is calculated therefrom. The K(2)SiF(6) is dissolved again and the fluoride content measured and recalculated as H(2)SiF(6). The results obtained with the presented method are discussed with respect to the results from two other, previously published methods, based on a titration using methanolic cyclohexylamine solution as titrant and based on a method using a fluoride ion selective electrode (F-ISE). An evaluation with respect to the needs for an industrial application is given. PMID:19071795

Acker, Jörg; Henßge, Antje

2007-06-15

369

Combustion mechanism of double-base propellant containing nitrogen heterocyclic nitroamines (II): The temperature distribution of the flame and its chemical structure  

NASA Astrophysics Data System (ADS)

In order to evaluate the actual pros and cons in the use of new nitroamines for solid rocket applications, the combustion properties of double-base propellants containing nitrogen heterocyclic nitroamines such as RDX, TNAD, HMX and DNP are investigated by means of high-speed photography technique, Non-contact wavelet-based measurement of flame temperature distribution. The chemical reactions in different combustion zone which control the burning characteristics of the double-base propellant containing nitrogen heterocyclic nitroamines were systematically investigated and descriptions of the detailed thermal decomposition mechanisms from solid phase to liquid phase or to gas phase are also included. It was indicated that the thermodynamic phase transition consisting of both evaporation and condensation of NC+NG, HMX, TNAD, RDX and DNP, are considered to provide a complete description of the mass transfer process in the combustion of these double-base propellants, and the combustion mechanisms of them are mainly involved with the oxidation mechanism of the NO 2, formaldehyde (CH 2O) and hydrogen cyanide (HCN). The entire oxidation reaction rate might be dependent on the pressure of the combustion chamber and temperature of the gas phase.

Yan, Qi-Long; Song, Zhen-Wei; Shi, Xiao-Bing; Yang, Zhi-Yuan; Zhang, Xiao-Hong

2009-03-01

370

Adsorption of Cu(II), Ni(II) and Zn(II) on modified jute fibres  

Microsoft Academic Search

The potential of a lignocellulosic fibre, jute, was assessed for adsorption of heavy metal ions like Cu(II), Ni(II) and Zn(II) from their aqueous solutions. The fibre was also used as adsorbent after chemically modifying it by two different techniques viz, loading of a dye with specific structure, C.I. Reactive Orange 13, and oxidising with hydrogen peroxide. Both the modified jute

S. R. Shukla; Roshan S. Pai

2005-01-01

371

Study of Chemical Surface Structure of Natural Sorbents Used for Removing of Pb2+ Ions from Model Aqueous Solutions (part Ii)  

NASA Astrophysics Data System (ADS)

This article presents the results of the chemical structure research of organic sorbent surface such as walnut shells, plums stones and sunflower hulls with using such methods as infrared spectrometry (FTIR) and elemental analysis. Based on the IR spectra identification of functional groups present on the surface of studied materials has been done as well as determination of their effect on the sorption mechanism of Pb2+ ions from aqueous model solutions W artykule przedstawiono wyniki bada? chemicznej struktury powierzchni sorbentów organicznych takich jak: ?upiny orzecha w?oskiego, pestki ?liwek oraz ?uski s?onecznika z wykorzystaniem metody spektrometrii w podczerwieni (FTIR) oraz analizy elementarnej. W oparciu o uzyskane widma IR dokonano identyfikacji grup funkcyjnych obecnych na powierzchni tych materia?ów i okre?lono ich wp?yw na mechanizm sorpcji jonów Pb2+ z modelowych roztworów wodnych. Analiza elementarna wykaza?a, ?e spo?ród badanych sorbentów, najwi?ksz? zawarto?? w?gla (49,91%) i wodoru (5,93%) maj? pestki ?liwek. Najwi?cej azotu (1,59%) zawieraj? ?uszczyny s?onecznika (tabela 1). Zawarto?? siarki we wszystkich badanych materia?ach jest znikoma, dlatego nie uda?o si? jej oznaczy? t? metod?. Obecno?? pozosta?ych pierwiastków mo?e ?wiadczy? o istnieniu zarówno alifatycznych jak i aromatycznych po??cze? organicznych. Potwierdzeniem tego s? równie? zarejestrowane widma IR (rysunki 1-3). W oparciu o uzyskane wyniki mo?na przypuszcza? tak?e, i? udzia? procesu wymiany jonowej w sorpcji o?owiu z roztworów wodnych jest znacz?cy. ?wiadcz? o tym m.in. intensywno?ci pasm na widmach IR dla próbek badanych materia?ów po ich kontakcie z roztworami jonów Pb2+ (rysunki 4-6).

Bo??cka, Agnieszka; Bo??cki, Piotr; Sanak-Rydlewska, Stanis?awa

2014-03-01

372

The conformational analysis of push-pull enaminoketones using Fourier transform IR and NMR spectroscopy, and quantum chemical calculations: II. ?-Dimethylaminoacrolein  

NASA Astrophysics Data System (ADS)

IR Fourier and 1H NMR spectra of ?-dimethylaminoacrolein (DMAA) were investigated in various pure solvents. Quantum chemical calculations by the method AM1 also was carried out to evaluate relative energy and dipole moment of each conformer. On the basis of NMR and IR-spectra we showed that the (DMAA) presented in solutions as equilibrium of two conformers, ( E- s- Z) ? ( E-s-E). Constant of this equilibrium, Keq = C( E- s- E)/ C( E- s- Z), depended strongly on the total (DMAA) concentration: ln K=ln K+a(1-e). Besides, ( E- s- Z) conformer of the (DMAA) was more polar and more stable than the ( E- s- E) conformer. Correlation of the out-of-phase ?˜(Cdbnd O) and in-phase ?˜(Cdbnd C) vibrations with solvatochromic parameters of Kamlet, Abbot, and Taft (KAT) revealed that the main contribution to the shift of the out-of-phase ?˜(Cdbnd O) vibrations of the both conformers made solvent's hydrogen bond acceptor (HBA) ( ?) term, whereas hydrogen bond donor (HBD) acidity ( ?) term influenced predominantly on the shift of the in-phase ?˜(Cdbnd C) vibrations of the conformers. Moreover, influence of these dominated terms was more pronounced for the ( E- s- Z) conformer in comparison with the ( E- s- E) conformer, hence the first conformer was more polarized than the last. Investigations of the enthalpies of the ( E- s- Z) ? ( E- s- E) equilibrium in carbon tetrachloride, 1,4-dioxane and their mixtures showed that these enthalpies depended predominantly on the solvent's atomic and electronic polarization and dispersive interactions.

Vdovenko, Sergey I.; Gerus, Igor I.; Fedorenko, Elena A.

2009-12-01

373

The conformational analysis of push-pull enaminoketones using Fourier transform IR and NMR spectroscopy, and quantum chemical calculations: II. Beta-dimethylaminoacrolein.  

PubMed

IR Fourier and (1)H NMR spectra of beta-dimethylaminoacrolein (DMAA) were investigated in various pure solvents. Quantum chemical calculations by the method AM1 also was carried out to evaluate relative energy and dipole moment of each conformer. On the basis of NMR and IR-spectra we showed that the (DMAA) presented in solutions as equilibrium of two conformers, (E-s-Z) <==> (E-s-E). Constant of this equilibrium, K(eq) = C(E-s-E)/C(E-s-Z), depended strongly on the total (DMAA) concentration: ln K(eq) = ln K(eq0) + a(1 - e(-bC) total). Besides, (E-s-Z) conformer of the (DMAA) was more polar and more stable than the (E-s-E) conformer. Correlation of the out-of-phase nu(C=O) and in-phase nu(C=C) vibrations with solvatochromic parameters of Kamlet, Abbot, and Taft (KAT) revealed that the main contribution to the shift of the out-of-phase nu(C=O) vibrations of the both conformers made solvent's hydrogen bond acceptor (HBA) (beta) term, whereas hydrogen bond donor (HBD) acidity (alpha) term influenced predominantly on the shift of the in-phase nu(C=C) vibrations of the conformers. Moreover, influence of these dominated terms was more pronounced for the (E-s-Z) conformer in comparison with the (E-s-E) conformer, hence the first conformer was more polarized than the last. Investigations of the enthalpies of the (E-s-Z) <==> (E-s-E) equilibrium in carbon tetrachloride, 1,4-dioxane and their mixtures showed that these enthalpies depended predominantly on the solvent's atomic and electronic polarization and dispersive interactions. PMID:19800286

Vdovenko, Sergey I; Gerus, Igor I; Fedorenko, Elena A

2009-12-01

374

Physical and chemical properties of the regional mixed layer of Mexico's Megapolis – Part II: Evaluation of measured and modeled trace gases and particle size distributions  

SciTech Connect

This study extends the work of Baumgardner et al. (2009) in which measurements of trace gases and particles at a remote, high-altitude mountain site 60 km from Mexico City were analyzed with respect to the origin of air masses. In the current evaluation, the temperature, water vapor, ozone (O3), carbon monoxide (CO), acyl peroxy nitrate (APN) and particle size distributions (PSDs) of the mass concentrations of sulfate, nitrate, ammonium and organic mass (OM) were simulated with the WRF-Chem chemical transport model and compared with the measurements at the mountain site. The model prediction of the diurnal trends of the gases were well correlated with the measurements before the regional boundary layer reached the measurement site but underestimated the concentrations after that time. The differences are caused by an overly rapid growth of the boundary layer by the model with too much dilution. There also appears to be more O3 produced by photochemical production, downwind of the emission sources, than predicted by the model. The measured and modeled PSDs compare very well with respect to their general shape and diameter of the peak concentrations. The spectra are log normally distributed with most of the mass in the accumulation mode and the geometric diameter centered at 200 ±20 nm, with little observed or predicted change with respect to the origin of the air mass or the time when the RBL is above the Altzomoni research. Only the total mass changed with time and air mass origin. The invariability of the average diameter of the accumulation mode suggests that there is very little growth of the particles by condensation or coagulation after six hours of aging downwind of the major sources of anthropogenic emissions in Mexico’s Megapolis.

Ochoa, Carlos; Baumgardner, Darrel; Grutter, M.; Allan, James D.; Fast, Jerome D.; Rappengluck, B.

2012-10-31

375

Alaska and Western Canada Collection  

NSDL National Science Digital Library

The University of Washington Libraries Digital Collections continues to break new and interesting ground with one of their latest offerings, which happens to focus in on Alaska and the Canadian provinces of Yukon Territory and British Columbia. With extensive archival holdings in both areas, they are certainly well poised to do so, and this particular collection includes visual materials related to the famed Gold Rush of 1898 to 1900, mining activities, and World War II installations. As with previous collections from this series, visitors can type keywords into the search engine, or they can search by category. The Gold Rush section is a real gem, as it includes 225 images in total. They include an illustration of a miner's working outfit from 1897, a photograph of a mining town dance from 1900, and a harrowing photograph of a boat navigating the treacherous Miles Canyon along the Yukon River.

376

The Tox21 robotic platform for the assessment of environmental chemicals - from vision to reality.  

PubMed

Since its establishment in 2008, the US Tox21 inter-agency collaboration has made great progress in developing and evaluating cellular models for the evaluation of environmental chemicals as a proof of principle. Currently, the program has entered its production phase (Tox21 Phase II) focusing initially on the areas of modulation of nuclear receptors and stress response pathways. During Tox21 Phase II, the set of chemicals to be tested has been expanded to nearly 10,000 (10K) compounds and a fully automated screening platform has been implemented. The Tox21 robotic system combined with informatics efforts is capable of screening and profiling the collection of 10K environmental chemicals in triplicate in a week. In this article, we describe the Tox21 screening process, compound library preparation, data processing, and robotic system validation. PMID:23732176

Attene-Ramos, Matias S; Miller, Nicole; Huang, Ruili; Michael, Sam; Itkin, Misha; Kavlock, Robert J; Austin, Christopher P; Shinn, Paul; Simeonov, Anton; Tice, Raymond R; Xia, Menghang

2013-08-01

377

Simulating Inorganic Aerosol Components Using ISORROPIA II in a Chemical Transport Model (PMCAMx) - Evaluation for the MILAGRO Campaign 2006 in Mexico City  

NASA Astrophysics Data System (ADS)

Aerosols have a significant role in the atmosphere having adverse impacts on human health and directly affecting air quality, visibility and climate change. One of the most challenging tasks for the available models is the prediction of the partitioning of the semivolatile inorganic aerosol components (ammonia, nitric acid, hydrochloric acid, etc) between the gas and aerosol phases. Moreover, the effects of mineral aerosols in the atmosphere remain largely unquantified. As a result, most current models have serious difficulties in reproducing the observed particulate nitrate and chloride concentrations. The aerosol thermodynamic model ISORROPIA has been improved as it now simulates explicitly the chemistry of Ca, Mg, and K salts and is linked to PMCAMx (Gaydos et al., 2007). PMCAMx also includes the inorganic aerosol growth module (Gaydos et al., 2003; Koo et al., 2003a) and the aqueous-phase chemistry module (Fahey and Pandis, 2001). The hybrid approach (Koo et al., 2003b) for modeling aerosol dynamics is applied in order to accurately simulate the inorganic components in coarse mode. This approach assumes that the smallest particles are in equilibrium while the condensation/evaporation equation is solved for the larger ones. PMCAMx is applied in Mexico City Metropolitan Area (MCMA) covering a 180x180x6 km region. The emission inventory used has as a starting point the MCMA 2004 official emissions inventory (CAM, 2006) and includes more accurate dust and NaCl emissions. The March 2006 dataset (MILAGRO Campaign) is used to evaluate the inorganic aerosol module of PMCAMx in order to test our understanding of aerosol thermodynamics and the equilibrium assumption. Gaydos, T., Pinder, R., Koo, B., Fahey, ?., Yarwood, G., and Pandis, S. N., (2007). Development and application of a three-dimensional Chemical Transport Model, PMCAMx. Atmospheric Environment, 41, 2594- 2611. Gaydos, T., Koo, B., and Pandis, S. N., (2003). Development and application of an efficient moving sectional approach for the solution of the atmospheric aerosol condensation/evaporation equations. Atmospheric Environment, 37, 3303-3316. Fahey, K. and Pandis, S. N., (2001). Optimizing model performance: variable size resolution in cloud chemistry modelling. Atmospheric Environment 35, 4471-4478. Koo, B., Pandis S. N., and Ansari, A. (2003a). Integrated approaches to modelling the organic and inorganic atmospheric aerosol components. Atmospheric Environment, 37, 4757-4768. Koo, B., Gaydos, T.M., Pandis, S.N., (2003b). Evaluation of the equilibrium, hybrid, and dynamic aerosol modeling approaches. Aerosol Science and Technology 37, 53-64.

Karydis, V. A.; Tsimpidi, A. P.; Nenes, A.; Pandis, S. N.; Zavala, M.; Lei, W.; Molina, L. T.

2007-12-01

378

Breaking Emulsions in Navy Bilge Collection and Treatment Systems.  

National Technical Information Service (NTIS)

The new bilge waste collection and treatment system, which serves as the collector, transporter and gravity separator for ship's bilge waste, has been shown to be a suitable medium for the application of chemical demulsification techniques. Chemical demul...

R. C. Little R. L. Patterson

1976-01-01

379

77 FR 31584 - Proposed Information Collection; Comment Request; Generic Clearance for Program Evaluation Data...  

Federal Register 2010, 2011, 2012, 2013

...strictly voluntary opinions and will not collect information that is required or regulated. Steps will be taken to assure anonymity of respondents in each activity covered under this request. II. Method of Collection NIST will collect this...

2012-05-29

380

Caratteristiche chimiche delle deposizioni atmosferiche raccolte presso le stazioni ENEA del Brasimone e di Bologna nel 1994/95. (Chemical characteristics of atmospheric deposition collected at two ENEA stations near Bologna).  

National Technical Information Service (NTIS)

This article presents the results of the measurements of the water quality in acid rains, collected by a Wet and Dry Sampler in 1994 and in 1995 at two ENEA stations, Brasimone and Bologna town, belonging to the RIDEP network and characterized by differen...

L. Barilli P. Olivieri S. Salvi L. Morselli E. Grandi

1997-01-01

381

Chemical Emergencies  

MedlinePLUS

... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by military ... there are no guarantees of safety during a chemical emergency, you can take actions to protect yourself. You ...

382

Three Compact, Robust Chemical Characterization Systems Suited To Sensitive, High Time Resolution Measurements Of Atmospheric Aerosols  

NASA Astrophysics Data System (ADS)

In the past decade, the advancement of compact, robust and sensitive instrumentation to measure the chemical characteristics of atmospheric aerosols has lagged behind their physical characterization. There is a need for chemical instrumentation with these three qualities for use on airborne platforms and at infrequently attended ground level surveillance sites. Now chemical techniques are appearing that promise to fill this need. We discuss three chemical characterization systems that are emerging in atmospheric chemistry and climate research applications. These are: (i) the Aerodyne mass spectrometer for real time measurement of particle composition and two post-collection analysis techniques (ii) non-destructive, multi-elemental chemical analysis of size-resolved samples by high spatial resolution synchrotron x-ray and proton beams (S-XRF/PIXE/PESA/STIM) (iii) single particle characterization by automated scanning electron microscopy with energy-dispersed detection of X-rays (SEM/EDX). The key to post-collection analysis is automated aerosol sizing and collection systems and automated chemical analysis systems. Together these techniques provide unique, comprehensive information on the organic and inorganic composition and morphology of particles and yet are easy to deploy in the field. The sensitivity of each technique is high enough to permit the rapid sampling needed to resolve spatial gradients in composition from a moving platform like the Battelle Gulfstream-159 aircraft, traveling at 100m/s.

Barrie, L. A.; Cowin, J. P.; Worsnop, D. R.

2001-12-01

383

Amazonian functional diversity from forest canopy chemical assembly  

PubMed Central

Patterns of tropical forest functional diversity express processes of ecological assembly at multiple geographic scales and aid in predicting ecological responses to environmental change. Tree canopy chemistry underpins forest functional diversity, but the interactive role of phylogeny and environment in determining the chemical traits of tropical trees is poorly known. Collecting and analyzing foliage in 2,420 canopy tree species across 19 forests in the western Amazon, we discovered (i) systematic, community-scale shifts in average canopy chemical traits along gradients of elevation and soil fertility; (ii) strong phylogenetic partitioning of structural and defense chemicals within communities independent of variation in environmental conditions; and (iii) strong environmental control on foliar phosphorus and calcium, the two rock-derived elements limiting CO2 uptake in tropical forests. These findings indicate that the chemical diversity of western Amazonian forests occurs in a regionally nested mosaic driven by long-term chemical trait adjustment of communities to large-scale environmental filters, particularly soils and climate, and is supported by phylogenetic divergence of traits essential to foliar survival under varying environmental conditions. Geographically nested patterns of forest canopy chemical traits will play a role in determining the response and functional rearrangement of western Amazonian ecosystems to changing land use and climate.

Asner, Gregory P.; Martin, Roberta E.; Tupayachi, Raul; Anderson, Christopher B.; Sinca, Felipe; Carranza-Jimenez, Loreli; Martinez, Paola

2014-01-01

384

Tortuous path chemical preconcentrator  

DOEpatents

A non-planar, tortuous path chemical preconcentrator has a high internal surface area having a heatable sorptive coating that can be used to selectively collect and concentrate one or more chemical species of interest from a fluid stream that can be rapidly released as a concentrated plug into an analytical or microanalytical chain for separation and detection. The non-planar chemical preconcentrator comprises a sorptive support structure having a tortuous flow path. The tortuosity provides repeated twists, turns, and bends to the flow, thereby increasing the interfacial contact between sample fluid stream and the sorptive material. The tortuous path also provides more opportunities for desorption and readsorption of volatile species. Further, the thermal efficiency of the tortuous path chemical preconcentrator is comparable or superior to the prior non-planar chemical preconcentrator. Finally, the tortuosity can be varied in different directions to optimize flow rates during the adsorption and desorption phases of operation of the preconcentrator.

Manginell, Ronald P. (Albuquerque, NM); Lewis, Patrick R. (Albuquerque, NM); Adkins, Douglas R. (Albuquerque, NM); Wheeler, David R. (Albuquerque, NM); Simonson, Robert J. (Cedar Crest, NM)

2010-09-21

385

40 CFR 761.253 - Chemical analysis.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Chemical analysis. 761.253 Section 761.253...Abandonment or Disposal of Natural Gas Pipeline: Selecting Sample Sites, Collecting...Samples § 761.253 Chemical analysis. (a) Extract PCBs...

2013-07-01

386

Dynamical quorum sensing and synchronization in large populations of chemical oscillators.  

PubMed

Populations of certain unicellular organisms, such as suspensions of yeast in nutrient solutions, undergo transitions to coordinated activity with increasing cell density. The collective behavior is believed to arise through communication by chemical signaling via the extracellular solution. We studied large, heterogeneous populations of discrete chemical oscillators (approximately 100,000) with well-defined kinetics to characterize two different types of density-dependent transitions to synchronized oscillatory behavior. For different chemical exchange rates between the oscillators and the surrounding solution, increasing oscillator density led to (i) the gradual synchronization of oscillatory activity, or (ii) the sudden "switching on" of synchronized oscillatory activity. We analyze the roles of oscillator density and exchange rate of signaling species in these transitions with a mathematical model of the interacting chemical oscillators. PMID:19179525

Taylor, Annette F; Tinsley, Mark R; Wang, Fang; Huang, Zhaoyang; Showalter, Kenneth

2009-01-30

387

75 FR 19385 - Agency Information Collection Activities; Proposed Collection; Comment Request; National Oil and...  

Federal Register 2010, 2011, 2012, 2013

...manufacturers of bioremediation agents, dispersants, surface collecting agents, surface...additives used as countermeasures against oil spills. Affected private industries...the Schedule), identifying ``dispersants, other chemicals, and other spill...October 18, 1991). The use of dispersants, other chemical agents, and biological additives to respond to oil......

2010-04-14

388

E-Collections  

NSDL National Science Digital Library

This new mailing list is designed for users involved in developing electronic collections of information. Suggested topics to be discussed include "collection development strategies, identifying/assessing/acquiring content, collaborative collecting at local/regional/national levels, and other topical aspects of electronic collection management." To join, send an email to: mailbase@mailbase.ac.uk In the body of the message, type: join e-collections yourfirstname yourlastname

Lee, Stuart.; Wise, Alicia.

389

75 FR 75703 - Notice of Information Collection  

Federal Register 2010, 2011, 2012, 2013

...II. Method of Collection NASA does not prescribe a format...used for proposal preparation. NASA encourages the use of computer...Data Title: JSC Cooperative Education Program--Housing Availability...performance of the functions of NASA, including whether the...

2010-12-06

390

75 FR 70298 - Notice of Information Collection  

Federal Register 2010, 2011, 2012, 2013

...358-1351, Lori.Parker@nasa.gov. SUPPLEMENTARY INFORMATION...This information is used by NASA to effectively maintain an appropriate...with institutions of higher education and other non-profit organizations...II. Method of Collection NASA is participating in...

2010-11-17

391

75 FR 80081 - Notice of Information Collection  

Federal Register 2010, 2011, 2012, 2013

...SUPPLEMENTARY INFORMATION: I. Abstract NASA will require responsible officials...long-standing and derives from NASA civil rights implementing regulation...VI of the Civil Rights Act of 1964. II. Method of Collection Paper...applicants. III. Data Title: NASA Assurance of Civil Rights...

2010-12-21

392

75 FR 65671 - Notice of Information Collection  

Federal Register 2010, 2011, 2012, 2013

...SUPPLEMENTARY INFORMATION: I. Abstract NASA will require responsible officials...long-standing and derives from NASA civil rights implementing regulation...VI of the Civil Rights Act of 1964. II. Method of Collection Paper...applicants. III. Data Title: NASA Assurance of Civil Rights...

2010-10-26

393

Biological Research Collections (BRC)  

NSF Publications Database

... thereafter SUMMARY OF PROGRAM REQUIREMENTS General Information Program Title: Biological Research ... in particular, and to biological sciences in general. II. PROGRAM DESCRIPTIONThe Biological ...

394

Biological Research Collections  

NSF Publications Database

... THEREAFTER SUMMARY OF PROGRAM REQUIREMENTS General Information Program Title: Biological Research ... in particular, and to biological sciences in general. II. PROGRAM DESCRIPTION The Biological ...

395

Chemical emergency preparedness program: chemical profiles. Interim guidance  

SciTech Connect

The document, developed by the U.S. Environmental Protection Agency (USEPA) is part of the USEPA National Air Toxics Strategy. The document is provided in support of EPA Chemical Emergency Preparedness Program (CEPP) which deals with accidental release of acutely toxic chemicals. For each acutely toxic chemical listed in the CEPP guidance document (report number PB86-155256), a chemical profile is available. A chemical profile is a collection of information on the chemical identity hazardous identity, physical/chemical characteristics, fire and explosive hazard, reactivity, health hazard, use, and precautions for handling and use of the chemical. The information is presented in the format that conforms as closely as possible to the Occupational Safety and Health Administration (OSHA) recommended format for a Material Safety Data Sheet (MSDS).

Not Available

1985-12-01

396

Chemical Health and Safety Data  

NSDL National Science Digital Library

These Chemical Health and Safety Data are an excellent resource for reliable, no-frills information from the National Toxicology Program (NTP). Data from "over 2000 chemicals studied by the NTP" are made available here, and users have a couple of different options for retrieving information. They may simply view a list of chemicals or search the Health and Safety database. Information on each chemical includes physical chemical data (like solubilities, solvents, volatility, flammability, and reactivity), toxicity data, handling procedures, emergency procedures, and a bibliographic list of sources for the information collected. Archived data may be downloaded (.sea, .zip).

397

Analysis of chemical warfare agents  

Microsoft Academic Search

A series of normal aliphatic thiols have been used to derivatise the chemical warfare agents Lewisites I and II (LI and LII) in hydrocarbon matrices. Varying the chain length of the thiol allowed adjustment of derivative tR by 5.9min for Lewisite I and 5.3min for Lewisite II. Linear regression analysis of the chain length of the thiol derivatives of the

Bob Muir; Ben J Slater; David B Cooper; Christopher M Timperley

2004-01-01

398

Chemicals, Health, Environment, and Me.  

ERIC Educational Resources Information Center

The CHEM (Chemicals, Health, Environment, and Me) Project is a series of 10 units designed to provide experiences for fifth and sixth graders that help them to accomplish an understanding of: (1) the nature of chemicals and how they interact with the environment; (2) how to collect, process, and analyze information; (3) how to use scientific…

California Univ., Berkeley. Lawrence Hall of Science.

399

Chemical composition of PM10 and PM2.5 collected at ground level and 100 meters during a strong winter-time pollution episode in Xi'an, China.  

PubMed

An intensive sampling of aerosol particles from ground level and 100 m was conducted during a strong pollution episode during the winter in Xi'an, China. Concentrations of water-soluble inorganic ions, carbonaceous compounds, and trace elements were determined to compare the composition of particulate matter (PM) at the two heights. PM mass concentrations were high at both stations: PM10 (PM with aerodynamic diameter < or =10 microm) exceeded the China National Air Quality Standard Class II value on three occasions, and PM2.5 (PM with aerodynamic diameter < or =2.5 microm) exceeded the daily U.S. National Ambient Air Quality Standard more than 10 times. The PM10 organic carbon (OC) and elemental carbon (EC) were slightly lower at the ground than at 100 m, both in terms of concentration and percentage of total mass, but OC and EC in PM2.5 exhibited the opposite pattern. Major ionic species, such as sulfate and nitrate, showed vertical variations similar to the carbonaceous aerosols. High sulfate concentrations indicated that coal combustion dominated the PM mass both at the ground and 100 m. Correlations between K+ and OC and EC at 100 m imply a strong influence from suburban biomass burning, whereas coal combustion and motor vehicle exhaust had a greater influence on the ground PM. Stable atmospheric conditions apparently led to the accumulation of PM, especially at 100 m, and these conditions contributed to the similarities in PM at the two elevations. Low coefficient of divergence (CD) values reflect the similarities in the composition of the aerosol between sites, but higher CDs for fine particles compared with coarse ones were consistent with the differences in emission sources between the ground and 100 m. PMID:22168098

Shen, Zhenxing; Cao, Junji; Liu, Suixin; Zhu, Chongshu; Wang, Xin; Zhang, Ting; Xu, Hongmei; Hu, Tafeng

2011-11-01

400

Chemical Threats  

MedlinePLUS

Chemical agents are poisonous vapors, aerosols, liquids and solids that have toxic effects on people, animals or plants. They ... hazard to people and the environment. Some chemical agents may be odorless and tasteless. They can have ...

401

Home Chemicals  

NSDL National Science Digital Library

This lesson provides an introduction to the occurrence and possible risks of household chemical products. Topics include some basic chemistry (how elements combine to form compounds), how chemicals are classified, and the idea of natural, as opposed to synthetic, chemicals. The lesson includes an activity in which students take an inventory of chemical products in their homes and research the possible hazards of some of them using an online resource developed by the National Institutes of Health (NIH).

Fox, Chris

402

Chemical Biology\\/ Chemical Genetics\\/ Chemical Genomics: Importance of Chemical Library  

Microsoft Academic Search

A new field of science, chemical biology\\/ chemical genetics\\/ chemical genomics (cb\\/cg\\/cg) has emerged since the late 1990's, especially in the United States. The NIH Roadmap agenda, Molecular Libraries Screening Center Network (MLSCN), became a drive force to push cb\\/cg\\/cg forward. Cb\\/cg\\/cg studies consist of three methodologies, chemical libraries with small molecules, high-throughput screenings, and computational databases. In this review,

Fumihiko Kugawa; Masaru Watanabe; Fuyuhiko Tamanoi

2007-01-01

403

Collecting Samples for Testing  

MedlinePLUS

... will be limited. Search Help? Collecting Samples for Testing Share this page: Was this page helpful? Introduction | ... From Within | Conclusion | Sources Overview Today's technologies allow testing on an impressively wide variety of samples collected ...

404

Chemical sensor  

NASA Technical Reports Server (NTRS)

A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

Rauh, R. David (Inventor)

1990-01-01

405

Chemical and Biological Weapons of Mass Destruction  

NSDL National Science Digital Library

Chemical warfare began in prehistoric times with the use of such weapons as poisoned arrows. However, World War I was the beginning of modern-day chemical warfare. The birth of biological warfare evolved during World War II. As a result, mankind has been plagued with chemical and biological weapons of mass destruction. This chapter provides a historical account of chemical and biological warfare, and its detrimental impact on society.

Slesnick, Irwin

2004-01-01

406

Nickel(II), palladium(II) and platinum(II) complexes of N -allyl- N ?-pyrimidin-2-ylthiourea  

Microsoft Academic Search

Platinum(II), palladium(II) and nickel(II) complexes with N-allyl-N?-pyrimidin-2-ylthiourea were synthesized in 1:1 and 1:2 [metal:ligand] stoichiometric ratios and characterized by elemental\\u000a analyses, molar conductivities, magnetic susceptibilities and by i.r., u.v.-vis., 1H- and 13C-n.m.r. and mass spectra. The 1H- and 13C- n.m.r. chemical shifts reveal coordination of one pyrimidine-N and sulphur atoms to PtII and PdII. The i.r. spectra indicate that the

Samir S. Kandil; Saud M. A. Katib; Naeema H. M. Yarkandi

2007-01-01

407

Guide to data collection  

NASA Technical Reports Server (NTRS)

Guidelines and recommendations are presented for the collection of software development data. Motivation and planning for, and implementation and management of, a data collection effort are discussed. Topics covered include types, sources, and availability of data; methods and costs of data collection; types of analyses supported; and warnings and suggestions based on software engineering laboratory (SEL) experiences. This document is intended as a practical guide for software managers and engineers, abstracted and generalized from 5 years of SEL data collection.

1981-01-01

408

Earthquake Photo Collections  

NSDL National Science Digital Library

This collection of earthquake photos, published by the United States Geological Survey (USGS), contains links to photos for specific earthquakes, as well as links to other USGS image collections and non-USGS collections. Highlights include photos from the 1906 San Francisco earthquake, the 1989 Loma Prieta earthquake, and the 1994 earthquake in Northridge, California. There is also a link to the USGS photo library (general geologic topics), and links to collections published by universities, museums, other government organizations, and professional organizations.

2011-06-21

409

Chemical warfare agents.  

PubMed

Chemical warfare agents (CWA's) are defined as any chemical substance whose toxic properties are utilised to kill, injure or incapacitate an enemy in warfare and associated military operations. Chemical agents have been used in war since times immemorial, but their use reached a peak during World War I. During World War II only the Germans used them in the infamous gas chambers. Since then these have been intermittently used both in war and acts of terrorisms. Many countries have stockpiles of these agents. There has been a legislative effort worldwide to ban the use of CWA's under the chemical weapons convention which came into force in 1997. However the manufacture of these agents cannot be completely prohibited as some of them have potential industrial uses. Moreover despite the remedial measures taken so far and worldwide condemnation, the ease of manufacturing these agents and effectiveness during combat or small scale terrorist operations still make them a powerful weapon to reckon with. These agents are classified according to mechanism of toxicity in humans into blister agents, nerve agents, asphyxiants, choking agents and incapacitating/behavior altering agents. Some of these agents can be as devastating as a nuclear bomb. In addition to immediate injuries caused by chemical agents, some of them are associated with long term morbidities and psychological problems. In this review we will discuss briefly about the historical background, properties, manufacture techniques and industrial uses, mechanism of toxicity, clinical features of exposure and pharmacological management of casualties caused by chemical agents. PMID:21783898

Chauhan, S; Chauhan, S; D'Cruz, R; Faruqi, S; Singh, K K; Varma, S; Singh, M; Karthik, V

2008-09-01

410

Juno II  

NASA Technical Reports Server (NTRS)

The Juno II launch vehicle, shown here, was a modified Jupiter Intermediate-Range Ballistic missionile, developed by Dr. Wernher von Braun and the rocket team at Redstone Arsenal in Huntsville, Alabama. Between December 1958 and April 1961, the Juno II launched space probes Pioneer III and IV, as well as Explorer satellites VII, VIII and XI.

1959-01-01

411

Collectivity and random interactions  

NASA Astrophysics Data System (ADS)

Diverse quantum systems, from nuclei to buckyballs to superconducting metals, often show similar collective behaviors, such as pairing or collective bands. These universalities show up when one uses random two-body interactions. In this talk I will discuss some new signatures of collectivity found in fermion systems with random interactions.

Johnson, Calvin

2006-10-01

412

Student Loan Collection Procedures.  

ERIC Educational Resources Information Center

This manual on the collection of student loans is intended for the use of business officers and loan collection personnel of colleges and universities of all sizes. The introductory chapter is an overview of sound collection practices and procedures. It discusses the making of a loan, in-school servicing of the accounts, the exit interview, the…

National Association of College and University Business Officers, Washington, DC.

413

Atmospheric Visualization Collection  

NSDL National Science Digital Library

The intent of the Atmospheric Visualization Collection (AVC) is to enhance physical science education and research through visualization of atmospheric data. This collection includes an archive of atmospheric data images and educational material based on these images. By utilizing collaborative digital library tools, a growing user community assists in the development of this collection.

Klaus, Christopher

2002-10-08

414

Alaska Collection Development Manual.  

ERIC Educational Resources Information Center

Written to guide librarians and staff in all types of libraries, this manual describes steps in the processes of writing collection development statements and assessing library collections. The first section focuses on the collection development policy--the benefits of a written policy, who should write the statement, and elements to be included.…

MacLean, Barbara; And Others

415

Stereodynamics of sterically crowded metal-phosphine complexes: trans-[(t-Bu){sub 2}P(l-Pr)]{sub 2}MCl{sub 2} [M = Pt(II) and Pd(II)]. One-dimensional dynamic and two-dimensional chemical exchange NMR studies, X-ray crystallographic studies, molecular conformation trapping, and molecular mechanics calculations  

SciTech Connect

By using complementary techniques including dynamic NMR (DNMR) spectroscopy, X-ray crystallography, molecular conformation trapping and molecular mechanics calculations, incisive pictures of the stereodynamics of two sterically crowded Pd(II) and Pt(II) complexes have been elucidated. X-ray crystallography shows that the molecular geometry in the only crystalline modification (P2{sub 1}/a space group) of trans-[(t-Bu){sub 2}P(i-Pr)]{sub 2}PdCl{sub 2} (1) has C{sub i} symmetry. The isopropyl groups are mutually anti; the dihedral angle between the two P-CH bonds is 180{degrees}. For the isopropyl group on each phosphine ligand, one methyl group is anti and the other gauche ot the palladium atom. There are significant torsions about Pd-P,P-(i-Pr) and P-(t-Bu) bonds including a dihedral angle between proximate P-CH and Pd-Cl bonds of 21.6{degrees}. On the basis of the hypotheses that (a) when placed in solution, the conformation of each phosphine ligand of 1 will adopt an essentially exclusive preference for that in the crystal and (b) the two phosphines act essentially independently of each other, four stable diastereomeric equilibrium conformations are predicted. In two diastereomeric conformations, the isopropyl groups are mutually syn with dihedral angles between the P-CH bonds of 44{degrees} (C{sub 2} symmetry) and 0{degrees} (C{sub s} symmetry). In the other two diastereomeric forms, the isopropyl groups are mutually anti with dihedral angles between the P-CH bonds of 136{degrees} (C{sub 2} symmetry) and 180{degrees} (C{sub i} symmetry). Two-dimensional {sup 31}P({sup 1}H) NMR chemical exchange spectroscopy in conjunction with theoretical simulations of the one-dimensional {sup 31}P({sup 1}H) and {sup 13}C({sup 1}H)DNMR spectra do reveal the presence of four diastereomeric equilibrium conformations and allow elucidation of the preferred conformational interconversion pathways. 32 refs., 8 figs., 1 tab.

DiMeglio, C.M.; Ahmed, K.J.; Luck, L.A.; Weltin, E.E. [Univ. of Vermont, Burlington, VT (United States)] [and others

1992-10-29

416

Non-planar chemical preconcentrator  

DOEpatents

A non-planar chemical preconcentrator comprises a high-surface area, low mass, three-dimensional, flow-through sorption support structure that can be coated or packed with a sorptive material. The sorptive material can collect and concentrate a chemical analyte from a fluid stream and rapidly release it as a very narrow temporal plug for improved separations in a microanalytical system. The non-planar chemical preconcentrator retains most of the thermal and fabrication benefits of a planar preconcentrator, but has improved ruggedness and uptake, while reducing sorptive coating concerns and extending the range of collectible analytes.

Manginell, Ronald P. (Albuquerque, NM); Adkins, Douglas R. (Albuquerque, NM); Sokolowski, Sara S. (Albuquerque, NM); Lewis, Patrick R. (Albuquerque, NM)

2006-10-10

417

Chemical engineer  

NSDL National Science Digital Library

What do chemical engineers actually do? This is the introductory page for a set of materials about chemical engineering as a career. Here the job of a chemical engineer is defined and described. Chemical engineers often work with industrial manufacturing processes that involve a mix of chemistry and engineering. In the rest of the resource, students can examine a specialized job title associated with chemical engineering: process engineer. Students can view a five-minute video clip of the process engineer as he works in a fertilizer plant making ammonia and urea. Students follow the engineer around the plant as he checks pressure in chemical lines. Students get a glimpse of the inside of a furnace during the chemical-making process. Copyright 2005 Eisenhower National Clearinghouse

Project, Iowa P.

2002-01-01

418

CLIC Digital Collections  

NSDL National Science Digital Library

The CLIC Digital Collections bring together digital collections from eight different colleges around the Twin Cities, including Hamline University and Macalester College. Here, visitors can take advantage of several collections from Macalester, including Macalester Views and Oral History Collections. The oral histories offer insight into the goings on around campus over the past several decades as told by faculty, students, and others. The Views provide over 150 items that tell the story of Macalester students in all different settings, including Ghana, El Paso, and Fiji. The site also includes a wonderful Fine Art Collection from St. Catherine University that connects students, faculty, staff, and the general public to meaningful works of art.

419

The Rochambeau Map Collection  

NSDL National Science Digital Library

Military maps continue to fascinate the general public, and this collection from the American Memory Project at the Library of Congress will be of great interest to those with a penchant for American history and cartography. This particular collection contains maps collected and used by Jean Baptiste Donatien de Vimeur, comte de Rochambeau during the American Revolution. Rochambeau served as the commander in chief of the French forces during the Revolution, and this collection contains numerous printed maps that cover much of the continent of North America. Visitors to the collection can search the collection by title, creator, subject, and geographic place. The collection has a number of highlights, including a number of views of Quebec City, maps of military fortifications, and the defenses of the city of Boston.

420

Detection of Chemical\\/Biological Agents and Stimulants using Quadrupole Ion Trap Mass Spectrometry  

Microsoft Academic Search

Detection of Chemical\\/Biological Agents and Simulants A new detector for chemical and biological agents is being developed for the U. S. Army under the Chemical and Biological Mass Spectrometer Block II program. The CBMS Block II is designed to optimize detection of both chemical and biological agents through the use of direct sampling inlets [I], a multi- ported sampling valve

S. H. Harmon; K. J. Hart; A. A. Vass; M. B. Wise; D. A. Wolf

1999-01-01