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1

Noninvasive Transdermal Chemical Collection. II. In vitro and in vivo Skin Permeability Studies  

Microsoft Academic Search

In vitro and in vivo skin permeability studies were conducted to investigate properties of several candidate transdermal chemical collection devices (TCDs). The TCD consists of a binding reservoir of activated charcoal suspended in a gel medium which is occlusively placed in direct contact with the skin. Binding of three model compounds (theophylline, methotrexate, and parathion) was studied in hydrophilic (agarose

Charles R. Bradley; Ramona G. Almirez; Dale P. Conner; Patricia R. Rhyne; Carl C. Peck

1990-01-01

2

Current Evaluation of the Millennium Phytomedicine-- Ginseng (II): Collected Chemical Entities, Modern Pharmacology, and Clinical Applications Emanated from Traditional Chinese Medicine  

PubMed Central

This review, a sequel to part 1 in the series, collects about 107 chemical entities separated from the roots, leaves and flower buds of Panax ginseng, quinquefolius and notoginseng, and categorizes these entities into about 18 groups based on their structural similarity. The bioactivities of these chemical entities are described. The ‘Yin and Yang’ theory and the fundamentals of the ‘five elements’ applied to the traditional Chinese medicine (TCM) are concisely introduced to help readers understand how ginseng balances the dynamic equilibrium of human physiological processes from the TCM perspectives. This paper concerns the observation and experimental investigation of biological activities of ginseng used in the TCM of past and present cultures. The current biological findings of ginseng and its medical applications are narrated and critically discussed, including 1) its antihyperglycemic effect that may benefit type II diabetics; in vitro and in vivo studies demonstrated protection of ginseng on beta-cells and obese diabetic mouse models. The related clinical trial results are stated. 2) its aphrodisiac effect and cardiovascular effect that partially attribute to ginseng’s bioactivity on nitric oxide (NO); 3) its cognitive effect and neuropharmacological effect that are intensively tested in various rat models using purified ginsenosides and show a hope to treat Parkinson’s disease (PD); 4) its uses as an adjuvant or immunotherapeutic agent to enhance immune activity, appetite and life quality of cancer patients during their chemotherapy and radiation. Although the apoptotic effect of ginsenosides, especially Rh2, Rg3 and Compound K, on various tumor cells has been shown via different pathways, their clinical effectiveness remains to be tested. This paper also updates the antioxidant, anti-inflammatory, anti-apoptotic and immune-stimulatory activities of ginseng, its ingredients and commercial products, as well as common side effects of ginseng mainly due to its overdose, and its pharmacokinetics.

Jia, Lee; Zhao, Yuqing; Liang, Xing-Jie

2009-01-01

3

Collection of Samples for Chemical Agent Analysis  

Microsoft Academic Search

This chapter describes procedures for the collection and analysis of samples of various matrices for the purpose of determining the presence of chemical agents in a civilian setting. This appendix is intended to provide the reader with sufficient information to make informed decisions about the sampling and analysis process and to suggest analytical strategies that might be implemented by the

C Koester; C Thompson; T Doerr; R Scripsick

2005-01-01

4

77 FR 59891 - Proposed Information Collection; Comment Request; Chemical Weapons Convention Declaration and...  

Federal Register 2010, 2011, 2012, 2013

...reports and inspections. This information is required for the United States to comply with the Chemical Weapons Convention (CWC), an international arms control treaty. II. Method of Collection Submitted electronically or on paper. III. Data OMB...

2012-10-01

5

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 ...

6

76 FR 7841 - Agency Information Collection Activities; Proposed Collections; Toxic Chemical Release Reporting...  

Federal Register 2010, 2011, 2012, 2013

...Collection Activities; Proposed Collections; Toxic Chemical Release Reporting; Request for...INFORMATION CONTACT: Cassandra Vail, Toxics Release Inventory Program Division...FURTHER INFORMATION CONTACT section. Title: Toxic Chemical Release Reporting (Form...

2011-02-11

7

Argus phase II optical data collection system  

NASA Astrophysics Data System (ADS)

The Argus aircraft is a highly modified NC-135E fitted with an infrared and ultraviolet-visible sensor suite for radiometric and spectral data collection. Each suite is operated independently with its own separate gimbal for precision pointing, telescope, and relay optics. The system includes a silica window for the ultraviolet-visible, and a zinc selenide window for the infrared. The entire system was developed and fabricated in-house at the Phillips Laboratory. All sensors are calibrated as a system onboard the aircraft through a unique facility called the aircraft optical calibration facility. The data is all recorded digitally, and can be transferred to secure data reduction facilities via optical fiber. The system is modular, in that the ultraviolet-visible and infrared benches can be separated, or the entire system can be quickly removed to allow for the introduction of other sensor suites or systems. The gimbals and telescopes can be used independently of the rest of the system. The aircraft is also fitted with an anemometry system, which can be operated independently of the sensor systems. This aircraft is capable of many types of missions, and will soon be fitted with a LIDAR system for remote sensing. The philosophy in building the system is to make it capable of quick changes during mission.

Wasson, Wayne E.

1996-11-01

8

COLLECTION AND CHEMICAL ANALYSIS OF LICHENS FOR BIOMONITORING  

EPA Science Inventory

This 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 th...

9

Device for collecting chemical compounds and related methods  

SciTech Connect

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

10

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

11

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

12

Chemical Composition of Wild2 Dust Collected by Stardust  

Microsoft Academic Search

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

G. J. Flynn

2006-01-01

13

Chemical analysis of rain samples collected over the Pacific Ocean  

Microsoft Academic Search

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, sigma=0.5). The

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

1990-01-01

14

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

2012-11-29

15

78 FR 9915 - Agency Information Collection Activities: Submission for OMB Review; Comment Request; Basel II...  

Federal Register 2010, 2011, 2012, 2013

...Review; Comment Request; Basel II Recordkeeping and Disclosures AGENCY: Federal Deposit...extend without revision its Basel II--Recordkeeping and Disclosures information collection...Title: Basel II: Disclosures and Recordkeeping. OMB Number: 3064-0153....

2013-02-12

16

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

17

Chemical Polishing of II-VI Compounds  

Microsoft Academic Search

The chemical polishing of the anion face of ZnO, ZnS, CdSe, and ZnTe and the cation face of CdSe and ZnTe with bromine dissolved in methanol has been accomplished. The etch rates of the bromine-methanol solution on the anion and cation faces of BeO, ZnO, ZnS, CdS, CdSe, ZnTe, and InSb have been measured at room temperature. An empirical relationship

W. H. Strehlow

1969-01-01

18

Mixing enhancement in chemical lasers. II. Theory  

SciTech Connect

A phenomenological model for reactant mixing in trip nozzle chemical lasers by means of a surface-stretching mechanism is used in conjunction with a two-level laser model to derive scaling laws for numerous features noted in the trip nozzle data. This mixing model is then employed with an aerokinetics code in order to obtain quantitative laser gain predictions. The results yielded by the code are in good agreement with small-signal data. It is determined that trip jet mixing will not increase laser efficiency at low cavity pressures, but will at high cavity pressures result in a doubling of laser power output. 12 references.

Driscoll, R.J.

1987-07-01

19

Dissecting chemical interactions governing RNA polymerase II transcriptional fidelity.  

PubMed

Maintaining high transcriptional fidelity is essential to life. For all eukaryotic organisms, RNA polymerase II (Pol II) is responsible for messenger RNA synthesis from the DNA template. Three key checkpoint steps are important in controlling Pol II transcriptional fidelity: nucleotide selection and incorporation, RNA transcript extension, and proofreading. Some types of DNA damage significantly reduce transcriptional fidelity. However, the chemical interactions governing each individual checkpoint step of Pol II transcriptional fidelity and the molecular basis of how subtle DNA base damage leads to significant losses of transcriptional fidelity are not fully understood. Here we use a series of "hydrogen bond deficient" nucleoside analogues to dissect chemical interactions governing Pol II transcriptional fidelity. We find that whereas hydrogen bonds between a Watson-Crick base pair of template DNA and incoming NTP are critical for efficient incorporation, they are not required for efficient transcript extension from this matched 3'-RNA end. In sharp contrast, the fidelity of extension is strongly dependent on the discrimination of an incorrect pattern of hydrogen bonds. We show that U:T wobble base interactions are critical to prevent extension of this mismatch by Pol II. Additionally, both hydrogen bonding and base stacking play important roles in controlling Pol II proofreading activity. Strong base stacking at the 3'-RNA terminus can compensate for loss of hydrogen bonds. Finally, we show that Pol II can distinguish very subtle size differences in template bases. The current work provides the first systematic evaluation of electrostatic and steric effects in controlling Pol II transcriptional fidelity. PMID:22509745

Kellinger, Matthew W; Ulrich, Sébastien; Chong, Jenny; Kool, Eric T; Wang, Dong

2012-05-02

20

Circadian rhythm data collection with the apple II microcomputer  

Microsoft Academic Search

Measurement of persistent circadian rhythms of bioluminescence in the marine dinoflagellate Gonyaulax polyedra has been automated using the Apple II microcomputer. The mechanics of the system are under software control and allow for the measurement of up to 60 different samples for periods of at least 3 weeks, with data points for each sample every 15 min. Experiments are presented

Walter Taylor; Steven Wilson; Robert Presswood; J. W. Hastings

1982-01-01

21

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

22

Computer simulation of plasma electron collection by PIX-II  

Microsoft Academic Search

A wake model was defined for the NASCAP\\/LEO finite element model for the plasma interaction experiment (PIX-II) launched to study the interaction between high-voltage large solar arrays with the space plasma environment. The cell surface model considers the individual cells, distances between interconnects, and the fraction of surface covered by interconnects. Account is taken of the electrostatic potential around the

M. J. Mandell; I. Katz

1985-01-01

23

Chemical values from solvent refined coal SRC-II  

Microsoft Academic Search

Gulf Oil Corp.'s SRC-II process, developed for the production of synthetic fuels from coal, can also produce chemical feedstocks. Estimates based on a 30,000 ton\\/day plant show that ethane-propane cracking would produce (in millions of lb\\/yr) 1100 of ethylene and 110 of propylene; conversion of the naphtha alone into aromatics would produce 970 of benzene, toluene, and xylenes (BTX); conversion

H. E. Swift; C. A. Sinnett; G. A. Harris

1980-01-01

24

Computer simulation of plasma electron collection by PIX-II  

SciTech Connect

A wake model was defined for the NASCAP/LEO finite element model for the plasma interaction experiment (PIX-II) launched to study the interaction between high-voltage large solar arrays with the space plasma environment. The cell surface model considers the individual cells, distances between interconnects, and the fraction of surface covered by interconnects. Account is taken of the electrostatic potential around the spacecraft, which travels at 7500 mps, over five times the speed of thermal ions. Ram ions are produced ahead of the array and the wake ion density is described with a geometric shadowing model. The model correctly predicted the currents in high and low bias voltages when compared to orbital data. The panel snapover, however, was projected to occur at 100 V and instead occurred at 300 V, which indicates that the snapover state is bistable. Finally, a low potential was both predicted and measured in the wake.

Mandell, M.J.; Katz, I.

1985-01-01

25

Quantum chaos in the nuclear collective model. II. Peres lattices  

SciTech Connect

This is a continuation of our paper [Phys. Rev. E 79, 046202 (2009)] devoted to signatures of quantum chaos in the geometric collective model of atomic nuclei. We apply the method by Peres to study ordered and disordered patterns in quantum spectra drawn as lattices in the plane of energy vs average of a chosen observable. Good qualitative agreement with standard measures of chaos is manifested. The method provides an efficient tool for studying structural changes in eigenstates across quantum spectra of general systems.

Stransky, Pavel; Hruska, Petr; Cejnar, Pavel [Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 180 00 Prague (Czech Republic)

2009-06-15

26

Chemical composition of cloudwater collected along the California coast  

SciTech Connect

Nocturnal fogs and low-lying clouds are frequent seasonal occurences along the California coast. During the summer, their frequency may exceed 50% at coastal sites. These clouds form at the base of the Pacific High inversion. Ventilation along the coast is further reduced by land/sea breeze systems, which recirculate the same air parcels several times across the coastline. During the past four years the authors have collected fog water at both urban and nonurban coastal sites. The locations and collection procedures are described. With the exception of one fog event in Morro Bay, all the fog-water sampled has been acidic. The highly acid samples were associated with large concentrations of SO/sub 4//sup 2 -/ and NO/sub 3//sup -/. Ammonia concentrations were comparatively low in the most acidic samples. The marine, continental, and anthropogenic contributions to the loading of solutes in fogwater were estimated using a step-wise fitting method. The sites in and around Los Angeles were most affected by anthropogenic sources. On an equivalent basis, NO/sub 3//sup -/ derived from secondary aerosol, was 2 to 3 times higher than SO/sub 4//sup 2 -/ in the Los Angeles basin. Substantial influences from continental and anthropogenic sources were observed even at the remote coastal sites. Because emissions of NH/sub 3/ and calcareous dust are slight along the coast, acid-neutralizing capacities in coastal air are insufficient to neutralize even small acid inputs.

Hoffmann, M.R.; Collett, J.; Daube, B.; Munger, J.W.

1986-04-01

27

The Mark A. Freeman collection of World War II photographs at George Eastman House  

Microsoft Academic Search

This thesis project is based on a collection of approximately 3000 World War II photographs, negatives, and supporting artefacts, which were donated to George Eastman House International Museum of Photography and Film (GEH) in 2007. The material was made and collected by Lieutenant Mark Anthony Freeman (1912-2005), a combat photographer for the US Army Signal Corps. The objectives for this

Lisa C Hennessey

2007-01-01

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

2013-09-30

30

Chemical values from solvent refined coal SRC-II  

SciTech Connect

Gulf Oil Corp.'s SRC-II process, developed for the production of synthetic fuels from coal, can also produce chemical feedstocks. Estimates based on a 30,000 ton/day plant show that ethane-propane cracking would produce (in millions of lb/yr) 1100 of ethylene and 110 of propylene; conversion of the naphtha alone into aromatics would produce 970 of benzene, toluene, and xylenes (BTX); conversion of the naphtha and light oil to aromatics would give 1500 of BTX and significant amounts of gasoline, jet fuel, and diesel fuel; and the light fuel oil alone, e.g., of Kentucky No. 9 coal, could yield 276 of phenol, 463 of cresols, and 64 of naphthalene. Detailed product slates and cost estimates projected for 1990 show that ethylene from ethane-propane cracking offers $0.016/lb advantage over a natural gas-derived feedstock; that cost of ethylene from SRC-II hydrotreated naphtha is comparable to that from a Kuwait full-range naphtha and higher than ethylene from Kuwait gas oil; and that the cost of BTX from SRC-II naphtha is $0.87/gal compared with $1.22/gal for petroleum naphtha-derived BTX. The coal-derived petrochemical feedstocks are expected to be competitive with the petroleum-derived feedstocks by 1990.

Swift, H.E.; Sinnett, C.A.; Harris, G.A.

1980-01-01

31

Collection of data and information the procedures for minimizing employee exposure to toxic chemical releases  

SciTech Connect

The objective of the study was to collect data and information from a sample of chemical manufacturing facilities and facilities that use chemicals in other processes to determine what kinds of procedures are currently in practice and to develop a set of recommended procedures that can be used to minimize the possibility of toxic chemical releases. The approach taken divides the project into three phases: what kinds of procedures are currently being used by the chemical industry and other facilities which use toxic chemicals; what types of chemical-release accidents and injuries occur in these facilities; and how can the information be integrated into a set of recommended procedures that will decrease the likelihood of a toxic chemical release of, if one does occur, will minimize the exposure and severity of exposure to employees. The report describes both the methodology used and the results of its application to the chemical industry. The report provides data collected from fifteen chemical plants and facilities that use toxic chemicals.

Plummer, R.W.; Stobbe, T.J.; Mogensen, J.E.

1986-06-01

32

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

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

Optimal control of solar energy collection in Solar House II at Colorado State University  

Microsoft Academic Search

An optimal controller of the second kind is one which maximizes the difference between the useful energy collected by a solar heating system and the associated pumping costs. This paper describes a method of implementing the optimal control strategy on a microprocessor based controller. The optimal controller built for Solar House II at Colorado State University, which has an air

R. C. Winn; C. B. Winn

1980-01-01

35

War of Hearts: Love and Collective Attachment as Integrating Factors in Finland During World War II  

Microsoft Academic Search

The article examines personal and collective bonds of attachment in war. The Finnish experience in World War II is used to bring together various theoretical viewpoints stretching from nationalism research to gender studies and from the history of emotions to psychoanalytically-oriented approaches. The aim is to understand the central and often perverted role of love both in the endurance and

2009-01-01

36

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

37

Astronomical IRFPA image collecting system based onb the NIOS II soft-core processor  

NASA Astrophysics Data System (ADS)

An astronomical infrared image collecting system based on the IRFPA (Infrared Focal Plane Array) is introduced. The principle and character of the IRFPA is described. It is focused on the discussing the electronic system architecture of the IRFPA image collecting system. The hardware and software design is built up based on the NIOS II soft-core processor. Finally two infrared images acquired by the IRFPA image collecting system is analysed. It is shown that the electronic system design for the IRFPA system can be used for the astronomical observation.

Qiu, Zhi-Qiang; Deng, Jian; Ye, Bin-Xun

2006-12-01

38

Chemical bath deposition of II-VI compound thin films  

NASA Astrophysics Data System (ADS)

II-VI compounds are direct bandgap semiconductors with great potentials in optoelectronic applications. Solar cells, where these materials are in greater demand, require a low cost production technology that will make the final product more affordable. Chemical bath deposition (CBD) a low cost growth technique capable of producing good quality thin film semiconductors over large area and at low temperature then becomes a suitable technology of choice. Heterogeneous reaction in a basic aqueous solution that is responsible for the II-VI compound film growth in CBD requires a metal complex. We have identified the stability constant (k) of the metal complex compatible with CBD growth mechanism to be about 106.9. This value is low enough to ensure that the substrate adsorbed complex relax for subsequent reaction with the chalcogen precursor to take place. It is also high enough to minimize the metal ion concentration in the bath participating in the precipitation of the bulk compounds. Homogeneous reaction that leads to precipitation in the reaction bath takes place because the solubility products of bulk II-VI compounds are very low. This reaction quickly depletes the bath of reactants, limit the film thickness, and degrade the film quality. While ZnS thin films are still hard to grow by CBD because of lack of suitable complexing agent, the homogeneous reaction still limits quality and thickness of both US and ZnS thin films. In this study, the zinc tetraammine complex ([Zn(NH3) 4]2+) with k = 108.9 has been forced to acquire its unsaturated form [Zn(NH3)3]2+ with a moderate k = 106.6 using hydrazine and nitrilotriacetate ion as complementary complexing agents and we have successfully grown ZnS thin films. We have also, minimized or eliminated the homogeneous reaction by using ammonium salt as a buffer and chemical bath with low reactant concentrations. These have allowed us to increase the saturation thickness of ZnS thin film by about 400% and raise that of US film form 0.2 to 0.5 mum with improved quality. A novel chemical activated diffusion of Cd into ZnS thin film at temperature lower than 100°C is also developed. This in conjunction with thermal activated diffusion at 400°C has enabled us to synthesize Cd1-xZn xS thin films suitable for solar cells from CBD grown CdS/ZnS multilayer. The potential application of the new Cd1-xZnxS/CdS/CdTe solar cell structure is also demonstrated. The unoptimized structure grown on transparent conducting oxide coated soda lime glass of 3mm thickness with no antireflection coating yielded a 10% efficiency. This efficiency is the highest ever recorded in any Cd1-xZnxS film containing CdTe solar cells.

Oladeji, Isaiah Olatunde

39

Chemical speciation of elements in stack-collected, respirable-size, coal fly ash  

Microsoft Academic Search

The data reported in this paper effectively complete the description of the chemical speciation of the elements in a set of four stack-collected coal fly ash samples which have been used extensively in the determination of the biological effects of coal fly ash. The association of elements with the aluminosilicate glass or surface salts, the association of cations and anions

Lee D. Hansen; David Silberman; Gerald L. Fisher; Delbert J. Eatough

1984-01-01

40

An Assessment of the Chemical Composition of Rain and Surface Water Samples Collected at Deep Creek Lake, Garrett County, Maryland.  

National Technical Information Service (NTIS)

This report presents the results of chemical analyses performed on rain and surface water samples collected at Deep Creek Lake, Maryland. Acidity and chemical composition of precipitation and surface waters were monitored to determine if acid rain and aci...

H. Scott S. Campbell M. Guiliano

1982-01-01

41

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

2013-10-03

42

Physical, Chemical, and Mineralogical Properties of Comet 81P\\/Wild 2 Particles Collected by Stardust  

Microsoft Academic Search

NASA’s Stardust spacecraft collected dust from the coma of Comet 81P\\/Wild 2 by impact into aerogel capture cells or into Al-foils.\\u000a The first direct, laboratory measurement of the physical, chemical, and mineralogical properties of cometary dust grains ranging\\u000a from ?15 to ?10?4 g were made on this dust. Deposition of material along the entry tracks in aerogel and the presence of

George James Flynn

2008-01-01

43

ANG II reduces net acid secretion in rat outer medullary collecting duct.  

PubMed

In rat outer medullary collecting duct (OMCD), the mechanism(s) and regulation of H+ secretion are not understood fully. The effect of changes in acid-base balance and the renin-angiotensin system on net H+ secretion was explored. Rats received NaCl, NaHCO3, NH4Cl, or nothing in their drinking water for 7 days. Total ammonia and total CO2 (JtCO2) fluxes were measured in OMCD tubules perfused in vitro from rats in each treatment group. JtCO2 was reduced in tubules from rats drinking NH4Cl relative to those drinking NaHCO3. Because NH4Cl intake increases plasma renin and aldosterone, we asked if upregulation of the renin-angiotensin system reduces net H+ secretion. Deoxycorticosterone pivalate administered in vivo did not affect JtCO2. However, ANG II given in vivo at 0.1 ng/min reduced JtCO2 by 35%. To determine if ANG II has a direct effect on acid secretion, JtCO2 was measured with ANG II applied in vitro. ANG II (10-8 M) present in the bath solution reduced JtCO2 by 35%. This ANG II effect was not observed in the presence of the AT1 receptor blocker candesartan. In conclusion, in rat OMCD, JtCO2 is paradoxically reduced with NH4Cl ingestion. Increased circulating ANG II, as occurs during metabolic acidosis, reduces JtCO2. PMID:12851254

Wall, Susan M; Fischer, Michael P; Glapion, Dawn M; De La Calzada, Mae

2003-07-08

44

The NCGC Pharmaceutical Collection: A comprehensive resource of clinically approved drugs enabling repurposing and chemical genomics  

PubMed Central

Small-molecule compounds approved for use as drugs may be “repurposed” for new indications and studied to determine the mechanisms of their beneficial and adverse effects. A comprehensive collection of all small-molecule drugs approved for human use would be invaluable for systematic repurposing across human diseases, particularly for rare and neglected diseases, for which the cost and time required for development of a new chemical entity are often prohibitive. Previous efforts to build such a comprehensive collection have been limited by the complexities, redundancies, and semantic inconsistencies of drug naming within and among regulatory agencies worldwide; a lack of clear conceptualization of what constitutes a drug; and a lack of access to physical samples. We report here the creation of a definitive, complete, and nonredundant list of all approved molecular entities as a freely available electronic resource and a physical collection of small molecules amenable to high-throughput screening.

Huang, Ruili; Southall, Noel; Wang, Yuhong; Yasgar, Adam; Shinn, Paul; Jadhav, Ajit; Nguyen, Dac-Trung; Austin, Christopher P.

2011-01-01

45

Substrate stiffness regulates cadherin-dependent collective migration through myosin-II contractility  

PubMed Central

The mechanical microenvironment is known to influence single-cell migration; however, the extent to which mechanical cues affect collective migration of adherent cells is not well understood. We measured the effects of varying substrate compliance on individual cell migratory properties in an epithelial wound-healing assay. Increasing substrate stiffness increased collective cell migration speed, persistence, and directionality as well as the coordination of cell movements. Dynamic analysis revealed that wounding initiated a wave of motion coordination from the wound edge into the sheet. This was accompanied by a front-to-back gradient of myosin-II activation and establishment of cell polarity. The propagation was faster and farther reaching on stiff substrates, indicating that substrate stiffness affects the transmission of directional cues. Manipulation of myosin-II activity and cadherin–catenin complexes revealed that this transmission is mediated by coupling of contractile forces between neighboring cells. Thus, our findings suggest that the mechanical environment integrates in a feedback with cell contractility and cell–cell adhesion to regulate collective migration.

Ng, Mei Rosa; Besser, Achim

2012-01-01

46

Substrate stiffness regulates cadherin-dependent collective migration through myosin-II contractility.  

PubMed

The mechanical microenvironment is known to influence single-cell migration; however, the extent to which mechanical cues affect collective migration of adherent cells is not well understood. We measured the effects of varying substrate compliance on individual cell migratory properties in an epithelial wound-healing assay. Increasing substrate stiffness increased collective cell migration speed, persistence, and directionality as well as the coordination of cell movements. Dynamic analysis revealed that wounding initiated a wave of motion coordination from the wound edge into the sheet. This was accompanied by a front-to-back gradient of myosin-II activation and establishment of cell polarity. The propagation was faster and farther reaching on stiff substrates, indicating that substrate stiffness affects the transmission of directional cues. Manipulation of myosin-II activity and cadherin-catenin complexes revealed that this transmission is mediated by coupling of contractile forces between neighboring cells. Thus, our findings suggest that the mechanical environment integrates in a feedback with cell contractility and cell-cell adhesion to regulate collective migration. PMID:23091067

Ng, Mei Rosa; Besser, Achim; Danuser, Gaudenz; Brugge, Joan S

2012-10-22

47

Chemical syntheses and characterizations of II-VI semiconductor nanocrystals  

NASA Astrophysics Data System (ADS)

This thesis is mainly concerned with the chemical syntheses and property characterizations of a series of II-VI semiconductor nanocrystals. We have synthesized ZnTe and Cr doped ZnTe nanoparticles, ZnSe:en precursor nanoribbon arrays, and CdSe quantum dots (QDs) and tetrapods nanocrystals using simple chemical methods. Structures and compositions of the obtained nanocrystals are characterized by the high-resolution transmission electron microscopy (HRTEM), energy dispersion spectrometry (EDS), X-ray diffraction (XRD), X-ray fluorescence (XRF), and high-resolution scanning electron microscopy (HRSEM). The optical absorption spectroscopy, photoluminescence (PL), and field emission experiments are also carried out. ZnTe and Cr doped ZnTe nanoparticles (ZnTe:Cr) have been synthesized by colloidal nano-synthesis method. The characterizations by XRD, XRF, and TEM show that the synthesized ZnTe and ZnTe:Cr crystals have cubic structure and Cr is incorporated into ZnTe. The magnetic properties of ZnTe:Cr are investigated. A hysteresis is observed in the magnetization versus magnetic field measurements below 10K. The detailed analyses suggest that the hysteresis is possibly originated from the magnetic short-range orders of Zn1-xCrxTe compounds in the sample. Vertically-aligned ZnSe:en precursor nanoribbon arrays have been grown directly on Zn foil via a simple solvothermal procedure. The nanoribbons are 100 ˜ 300 nm in width and several nanometers in thickness. Their lengths are about a few micrometers. The conversion of the ZnSe:en nanoribbon arrays to ZnSe nanoribbon arrays with wurtzite structures is achieved by a thermal annealing in N2 atmosphere. Upon the release of en, the morphology of the ZnSe nanoribbon arrays is well-preserved and the crystallinity of the ribbons is improved. Uniform field emissions were observed from ZnSe nanoribbons. Results show that the ZnSe nanoribbon arrays are good field emitters in comparison with many other nanostructures as having a low turn-on field of 5 V/mum and a high field enhancement factor of 1382. CdSe tetrapod nanocrystals have been synthesized using a simple nano-synthesis method by controlling the protonic acidity of the cadmium OA-TOP precursor. The crystal structure of the tetrapods is determined by HRTEM analysis, which shows that the tetrapod has a zinc blende core and four wurtzite arms. The possible growth mechanism in our experiment is discussed. The electronic structure of tetrapod is calculated in comparison with the spherical dot, indicating that for our tetrapod samples the ground state is dominated by the core diameter and only for the states above the fourth excited state the "arm diameter" effect becomes important. The steady state and transient optical properties of CdSe tetrapods and QDs are studied in details. No qualitative differences are detected. The field emission properties of CdSe tetrapods with different arm lengths are also investigated in details, showing that the longer the arm length, the lower the turn-on field, and the higher the enhancement factor.

Zhao, Lijuan

48

Trends in chemical concentrations in mussels and oysters collected along the US coast from 1986 to 1993  

Microsoft Academic Search

Results from annual collections and chemical analyses of mussels and oysters from sites located throughout the marine coast of the United States show decreasing trends, on a national scale, for chemicals whose use has been banned or has greatly decreased. Concentrations of most other chemicals are neither increasing nor decreasing.

Thomas P. O'Connor

1996-01-01

49

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

50

Chemical Abundances in Virgo Spiral Galaxies. II. Effects of Cluster Environment  

Microsoft Academic Search

We present new measurements of chemical abundances in H II regions in spiral galaxies of the Virgo cluster and a comparison of Virgo galaxies and field spirals. With these new data there now exist nine Virgo spirals with abundance measurements for at least four H II regions. Our sample of Virgo galaxies ranges from H I deficient objects near the

Evan D. Skillman; Robert C. Kennicutt Jr.; Gregory A. Shields; Dennis Zaritsky

1996-01-01

51

Collection of airborne fluorinated organics and analysis by gas chromatography/chemical ionization mass spectrometry.  

PubMed

The ubiquitous detection of perfluorooctane sulfonate (PFOS) in humans and animals has produced a need for sensitive and compound-specific analytical methods to determine the environmental distribution of fluorinated organic contaminants. A suite of potential PFOS precursors (sulfonamides) and fluorotelomer alcohols (FTOHs) were separated by gas chromatography and detected by chemical ionization mass spectrometry (GC/CI-MS). Full-scan spectra were collected in both positive and negative chemical ionization (PCI and NCI, respectively) mode to determine retention time windows and fragmentation patterns. In selected ion monitoring (SIM) mode, instrumental detection limits ranged from 0.2 to 20 pg for individual analytes, depending on ionization mode. PCI mode was preferred for routine analysis because of the simple mass spectra produced, typified by the presence of a major molecular ion [M + H]+. High-volume air samplers collected gaseous and particle-bound fluoroorganics on composite media consisting of XAD-2, polyurethane foam (PUF), and quartz-fiber filters. The combined collection efficiency for individual analytes was 87 to 136% in breakthrough experiments. Application of the method to the analysis of ambient air from urban and rural sites confirmed the presence of six novel fluorinated atmospheric contaminants at picogram per meter3 concentrations. Low concentrations of fluoroorganics were consistently detected in blanks (<4 pg m(-3)); however, this did not prevent confirmation or quantification of environmental concentrations. PMID:11842814

Martin, Jonathan W; Muir, Derek C G; Moody, Cheryl A; Ellis, David A; Kwan, Wai Chi; Solomon, Keith R; Mabury, Scott A

2002-02-01

52

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

53

Chemical pollutants in field-collected canvasback tissues, eggs, and food materials  

USGS Publications Warehouse

In 1972 studies began on the levels of environmental pollutants in canvasback tissues, eggs, and food items. The purpose of the studies were to determine if the levels of toxic chemicals found in canvasbacks were of the magnitude to cause problems affecting reproduction and survival. Overall, levels of organochlorine pesticides and PCB's were low in canvasbacks and their eggs. Some individual birds, however, laid eggs with elevated residues of DDE (12.1 ppm) or PCB's (28.6 ppm). There was no significant difference between eggshell thicknesses of 1972-73 and pre-1946 collections. About 12% of the canvasbacks analyzed had elevated levels of blood lead with reduced ALAD enzyme activity. Adult canvasbacks collected from the Chesapeake Bay in 1975 had moderate to high levels of cadmium in their kidneys. Cadmium, in excessive amounts is very toxic and can curtail spermatogenesis in male birds. Although no single toxic chemical found in wild canvasbacks appears to be a major factor in population declines, the cumulative effects of sublethal levels of all the pollutants may render birds susceptible to disease, hunting pressure or predation.

White, D. H.; Dieter, M.P.; Stendell, R.C.

1976-01-01

54

Saponins from Vietnamese Ginseng, Panax vietnamensis HA et Grushv. Collected in central Vietnam. II.  

PubMed

Further investigation on the saponin composition of rhizomes and roots of Panax vietnamensis HA et GRUSHV. has resulted in the isolation and structural elucidation of seven new dammarane saponins named vina-ginsenosides-R3 (12), -R4 (11), -R5 (16), -R6 (17), -R7 (6), -R8 (20), -R9 (22), together with the identification of six known saponins including 20-gluco-ginsenoside-Rf (10), ginsenoside-Rc (4), notoginsenoside-R6 (9), quinquenoside-R1 (5), gypenoside XVII (2) and majoroside F1 (21). The structures of the novel saponins were established on the basis of chemical and spectral evidence. Vina-ginsenoside-R3 is the first naturally occurring glycoside of dammarenediol II, while vina-ginsenosides-R5 and -R6, two ocotillol-type saponins, are two other examples of saponins having the rare alpha-glucosyl linkage. PMID:8124758

Nguyen, M D; Kasai, R; Ohtani, K; Ito, A; Nguyen, T N; Yamasaki, K; Tanaka, O

1994-01-01

55

Synthesis of sol-gel silica chemically bonded with cyanex 272 for the removal of Cu(II), Ni(II), and Zn(II)  

Microsoft Academic Search

This article reported on the synthesis of SSCBB, a new solid-phase, sol-gel silica chemically bonded with [bis (2,4,4-trimethylpentyl)\\u000a phosphinate], (BTMPP, anion of Cyanex 272) prepared with a sol-gel method, and its application as a reusable solid-phase sorbent\\u000a for the selective removal of Cu(II), Ni(II), and Zn(II). The synthesized SSCBB was characterized by FTIR, EDX, SEM, BET, TGA,\\u000a and DSC. To

Fazlul Bari; Noorzahan Begum; Shamsul Baharin Jamaludin; Kamarudin Hussin

2009-01-01

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 fresh bee pollen collected in the Misintá páramo from the Venezuelan Andes].  

PubMed

Venezuelan bee pollen has not been characterized, and marketing is not regulated. Pollen is consumed for apitherapeutical purposes for its nutritional and medicinal properties. This product of the hive is the most popular after honey; therefore it is necessary to characterize and to value it to initiate a database to support the proposal of a norm for bee pollen quality control. Samples of bee pollen collected by bees in the Misintá páramo of Mérida state were characterized accoridng to the chemical composition (moisture, ash, fat, pH, proteins) of four color fractions (yellow, orange, ochre, green). Yellow pollen was the most frequent fraction, with 2.18 g ash/100 g, 5.37 g ether extract/100 g, 14.88 g moisture/100 g, and 37.32 g proteins/100 g. PMID:19368304

Vit, Patricia; Santiago, B

2008-12-01

58

SOME CHEMICAL AND MORPHOLOGICAL COMPARISONS OF LABORATORY-REARED AND FIELD-COLLECTED ADULT DIAPREPES ROOT WEEVIL  

Technology Transfer Automated Retrieval System (TEKTRAN)

Chemical and morphological comparisons showed differences between laboratory-reared and field-collected adult Diaprepes root weevils and between field-collected weevils from different host plants in different geographical areas in Florida. Lab-reared weevils were significantly larger in body size an...

59

Design of an artificial skin. II. Control of chemical composition.  

PubMed

Detailed methodology is described for the reproducible preparation of collagen--glycosaminoglycan (GAG) membranes with known chemical composition. These membranes have been used to cover satisfactorily large experimental full-thickness skin wounds in guinea pigs over the past few years. Such membranes have effectively protected these wounds from infection and fluid loss for over 25 days without rejection and without requiring change or other invasive manipulation. When appropriately designed for the purpose, the membranes have also strongly retarded wound contraction and have become replaced by newly synthesized, stable connective tissue. In our work, purified, fully native collagen from two mammalian sources is precipitated from acid dispersion by addition of chondroitin 6-sulfate. The relative amount of GAG in the coprecipitate varies with the amount of GAG added and with the pH. Since coprecipitated GAG is generally eluted from collagen fibers by physiological fluids, control of the chemical composition of membranes is arrived at by crosslinking the collagen--GAG ionic complex with glutaraldehyde, or, alternately, by use of high-temperature vacuum dehydration. Appropriate use of the crosslinking treatment allows separate study of changes in membrane composition due to elution of GAG by extracellular fluid in animal studies from changes in composition due to enzymatic degradation of the grafted or implanted membrane in these studies. Exhaustive in vitro elution studies extending up to 20 days showed that these crosslinking treatments insolubilize in an apparently permanent manner a fraction of the ionically complexed GAG, although it could not be directly confirmed that glutaraldehyde treatment covalently crosslinks GAG to collagen. By contrast, the available evidence suggests strongly that high-temperature vacuum dehydration leads to formation of chemical bonds between collagen and GAG. Procedures are described for control of insolubilized and "free" GAG in these membranes as well as for control of the molecular weight between crosslinks (Mc). The insolubilized GAG can be controlled in the range 0.5--10 wt. % while "free" GAG can be independently controlled up to at least 25 wt. %; Mc can be controlled in the range 2500--40,000. Studies by infrared spectroscopy have shown that treatment of collagen--GAG membranes by glutaraldehyde or under high-temperature vacuum does not alter the configuration of the collagen triple helix in the membranes. Neither do these treatments modify the native banding pattern of collagen as viewed by electron microscopy. Collagen--GAG membranes appear to be useful as chemically well-characterized, solid macromolecular probes of biomaterial--tissue interactions. PMID:7358747

Yannas, I V; Burke, J F; Gordon, P L; Huang, C; Rubenstein, R H

1980-03-01

60

Chemkin-II: A Fortran chemical kinetics package for the analysis of gas-phase chemical kinetics  

SciTech Connect

This document is the user's manual for the second-generation Chemkin package. Chemkin is a software package for whose purpose is to facilitate the formation, solution, and interpretation of problems involving elementary gas-phase chemical kinetics. It provides an especially flexible and powerful tool for incorporating complex chemical kinetics into simulations of fluid dynamics. The package consists of two major software components: an Interpreter and Gas-Phase Subroutine Library. The Interpreter is a program that reads a symbolic description of an elementary, user-specified chemical reaction mechanism. One output from the Interpreter is a data file that forms a link to the Gas-Phase Subroutine Library. This library is a collection of about 100 highly modular Fortran subroutines that may be called to return information on equation of state, thermodynamic properties, and chemical production rates.

Kee, R.J.; Rupley, F.M.; Miller, J.A.

1989-09-01

61

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

SciTech Connect

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 internal combustion engine simulation. It is our hope is that these notes summarize some of the necessary background material in fluid mechanics and combustion, explain the numerical methods currently used in KIVA-II and similar combustion codes, and provide an outline of the overall structure of KIVA-II as a representative combustion program, in order to aid the researcher in the task of implementing KIVA-II or a similar combustion code on a massively parallel computer. The notes are organized into three parts as follows. In Part I, we give a brief introduction to continuum mechanics, to fluid mechanics, and to the mechanics of chemically reactive fluids with sprays. In Part II, we take a close look at the governing equations of KIVA-II, and discuss the methods employed in the numerical solution of these equations. We draw some conclusions and make some observations in Part III.

Holst, M.J. [Illinois Univ., Urbana, IL (United States). Dept. of Computer Science

1992-09-01

62

Role of transition metal ferrocyanides (II) in chemical evolution  

NASA Astrophysics Data System (ADS)

Due to ease of formation of cyanide under prebiotic conditions, cyanide ion might have formed stable complexes with transition metal ions on the primitive earth. In the course of chemical evolution insoluble metal cyano complexes, which settled at the bottom of primeval sea could have formed peptide and metal amino acid complexes through adsorption processes of amino acids onto these metal cyano complexes. Adsorption of amino acids such as glycine, aspartic acid, and histidine on copper ferrocyanide and zinc ferrocyanide have been studied over a wide pH range of 3.6 8.5. Amino acids were adsorbed on the metal ferrocyanide complexes for different time periods. The progress of the adsorption was followed spectro-photometrically using ninhydrin reagent. Histidine was found to show maximum adsorption on both the adsorbents at neutral pH. Zinc ferrocyanide exhibits good sorption behaviour for all the three amino acids used in these investigations.

Kamaluddin; Nath, Mala; Deopujari, Sushama W.; Sharma, Archana

1990-05-01

63

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

64

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

65

Chemical warfare agents: their past and continuing threat and evolving therapies. Part II of II.  

PubMed

Chemical warfare agents are ideal weapons for terrorists and for use in military operations against both civilian populations and troops. Thus, there have been efforts by the United States in cooperation with other concerned nations to develop animal models to understand the pathophysiology of the injuries induced by these agents, and to develop suitable animal models for testing of pre-and post-exposure protectants and therapies. Sulfur mustard remains the most significant chemical warfare agent that produces cutaneous injuries. Institution of standard recommendations prior to threatened exposure or after exposure are something that we need to be aware of in the world we live in. In addition, pre-and post-exposure therapies now being studied offer hope for moderating the mortality and morbidity that can result from chemical exposure. PMID:14673262

Smith, Kathleen J; Skelton, Henry

66

Adsorption of Pb(II) From Aqueous Solutions by Chemically Modified Zeolite Supported Carbon Nanotubes: Equilibrium, Kinetic and Thermodynamic Studies  

Microsoft Academic Search

Zeolite supported carbon nanotubes (ZCNTs) were synthesized by the catalytic chemical vapor deposition (CCVD) method. The physical and chemical properties such as surface area, pore diameter, surface functional groups and total acidic and basic sites of the ZCNTs were studied. They were employed as adsorbent to study the adsorption characteristics of Pb(II) in aqueous solution. The adsorption of Pb(II), increase

D. K. Venkata Ramana; D. Harikishore Kumar Reddy; B. Naresh Kumar; K. Seshaiah; G. Purna Chandra Rao; Chungsying Lu

2012-01-01

67

Preparation of polyethylene sacks for collection of precipitation samples for chemical analysis  

USGS Publications Warehouse

Polyethylene sacks are used to collect precipitation samples. Washing polyethylene with acetone, hexane, methanol, or nitric acid can change the adsorptive characteristics of the polyethylene. In this study, simulated precipitation at pH 4.5 was in contact with the polyethylene sacks for 21 days; subsamples were removed for chemical analysis at 7, 14, and 21 days after intitial contact. Sacks washed with acetone adsorbed iron and lithium; sacks washed with hexane adsorbed barium, iron , and lithium; sacks washed with methanol adsorbed calcium and iron; and sacks washed with 0.30 N nitric acid adsorbed iron. Leaching the plastic sacks with 0.15 N nitric acid did not result in 100-percent recovery of any of the adsorbed metals. Washing polyethylene sacks with dilute nitric acid caused the pH of the simulated precipitation to be decreased by 0.2 pH unit after 1 week of contact with the polyethylene. The specific conductance increased by 10 microsiemens per centimeter. Contamination of precipitation samples by lead was determined to be about 0.1 microgram per liter from contact with precleaned polyethylene sacks. No measurable contamination of precipitation samples by zinc occurred. (USGS)

Schroder, L. J.; Bricker, A. W.

1985-01-01

68

Physical and chemical structure of the IC 63 nebula. II. Chemical models  

Microsoft Academic Search

Chemical models are presented for the photon dominated region (PDR) IC 63, a small isolated molecular cloud located close to the B0.5 IVpe star gamma Cas for which we have presented observations of various molecular species in an earlier paper, and for which observations of ionized and neutral atomic carbon, as well as additional CO observations, are available. The models

D. J. Jansen; E. F. van Dishoeck; J. H. Black; M. Spaans; C. Sosin

1995-01-01

69

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

70

Chemical characteristics of negative-tone chemically amplified resist for advanced mask making: II  

NASA Astrophysics Data System (ADS)

?We investigated the film property and the lithographic performance of five commercialized NCARs. This report focused on Cr effect and PCD stability which are critical issues on advanced mask making. Results confirmed to solve the Cr effect by controlled dissolution rate of resist film. Furthermore, PCD was occurred by PAG moving and unsuitable reaction in the resist film standing delay time. This report suggests the strategy that was design of chemical structure for the next generation NCARs.

Takeshi, Kazumasa; Tanabe, Masahito; Inokuchi, Daisuke; Fukushima, Yuichi; Okumoto, Yasuhiro; Okuda, Yoshimitsu

2004-10-01

71

Chemical recognition phase of the fluorescence chemical sensor for copper (II) ions in aqueous solution  

NASA Astrophysics Data System (ADS)

We review the principles of optical sensor based on the use of the sol-gel technique, in particular their fabrication. We also report on potential applications of the recognition phases prepared by encapsulation of fluorescent chemosensors which have been designed by means of a supramolecular approach: two anthryl groups linked to diaminodiethero group. Occurrence of the metal ion-receptor interaction is signaled through the enhancement of anthryl fluorescence. The enhancement takes place when the receptor is able to promote a photoinduced electron transfer mechanism. Cu(II) ions can be distinguished form other transition metal ions in aqueous solution by the recognition phase.

Klonkowski, Andrzej M.; Kledzik, K.; Ostaszewski, R.

2001-08-01

72

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

73

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

2011-01-13

74

Information collection request for proposed National Primary Drinking Water Regulations for synthetic organic chemicals (draft), April 1989  

SciTech Connect

The Environmental Protection Agency (EPA), under the requirements of the Safe Drinking Water Act (Section 1401 and 1412, P.L. 99-339, as amended in 1986), has proposed National Primary Drinking Water Regulations (NPDWR) pertaining to the contamination of public water systems by synthetic organic chemical (SOCs) contaminants. The proposed regulations require the collection of information by public water systems, states, and the EPA. Information collection requirements include monitoring, reporting, and recordkeeping activities that are discussed in this Information Collection Requests (ICR) document.

Not Available

1989-04-01

75

Transcutaneous Chemical Collection of Caffeine in Normal Subjects: Relationship to Area Under the Plasma Concentration-Time Curve and Sweat Production  

Microsoft Academic Search

A novel transcutaneous chemical collection device (TCD) has been developed to study the phenomenon of outward transcutaneous chemical migration. The TCD is a Bandaid-like device containing an immobilized aqueous media and binding reservoir material to prevent back-transfer into the skin. This device, when placed against the skin, allows collection and quantitation of chemicals that diffuse directly through the skin from

Dale P. Conner; Emily Millora; Kaveh Zamani; Darrell Nix; Ramona G. Almirez; Patricia Rhyne-Kirsch; Carl C. Peck

1991-01-01

76

78 FR 17680 - Information Collection Request; Chemical Facility Anti-Terrorism Standards Personnel Surety Program  

Federal Register 2010, 2011, 2012, 2013

...parent companies, may choose to comply with RBPS 12(iv) by outsourcing the information submission process to third parties...data collection, submissions, and tracking; (3) cost of training facility personnel to maintain the data collection,...

2013-03-22

77

Alaska Frozen Tissue Collection: A Resource for Marine Biotechnology, Phase II.  

National Technical Information Service (NTIS)

The 23-page report describes the Alaska Frozen Tissue Collection (AFTC), highlighting marine mammal tissues collected, listing independent analyses of AFTC tissues, and describing their mammal and AFTC interactive database summary now accessible on the Wo...

J. A. Cook G. H. Jarrell

2002-01-01

78

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

79

KIVA-II: A computer program for chemically reactive flows with sprays  

SciTech Connect

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 accuracy and efficiency and its ease-of-use. The KIVA-II equations and numerical solution procedures are very general and can be applied to laminar or turbulent flows, subsonic or supersonic flows, and single-phase or dispersed two-phase flows. Arbitrary numbers of species and chemical reactions are allowed. A stochastic particle method is used to calculate evaporating liquid sprays, including the effects of droplet collisions and aerodynamic breakups. Although the initial and boundary conditions and mesh generation have been written for internal combustion engine calculations, the logic for these specifications can be easily modified for a variety of other applications. Following an overview of the principal features of the KIVA-II program, we describe in detail the equations solved, the numerical solution procedure, and the structure of the computer program. Sixteen appendices provide additional details concerning the numerical solution procedure. 67 refs., 29 figs.

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

1989-05-01

80

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); Ellis, Christopher R. B. (Oakland, CA)

2010-08-17

81

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

82

Metabolic profiling of GuanXin II prescription based on metabolic fingerprinting and chemical analysis  

Microsoft Academic Search

A sensitive LC\\/MS method was established to investigate the in vivo metabolism of GuanXin II prescription, a five-component Chinese herbal medicine formulation. Rat plasma, bile, urine, and feces were collected and analyzed following oral administration of the water decoction. A total of 50 compounds were identified, including 17 prototypes and 33 metabolites underwent methylation, oxidation, hydrolysis, sulfate conjugation, glucuronide conjugation,

Xue Qiao; Jian Han; Man Xu; Zi-chuan Zhang; Min Ye; Guan Ye; De-an Guo

2011-01-01

83

The 5200-Åflux depression of chemically peculiar stars - II. The cool chemically peculiar and ? Bootis stars  

NASA Astrophysics Data System (ADS)

After establishing the synthetic ?a photometric system in the first paper of this series, we now present model atmospheres computed with individual abundances for a representative sample of chemically peculiar (CP) stars and either confirm or redetermine their input parameters through comparisons with photometric, spectrophotometric and high-resolution spectroscopic data. The final models obtained from this procedure were used to compute synthetic ?a indices which were compared with observations. The observed behaviour of ?a is reproduced for several types of CP stars: models for Am stars show negligible (or marginally positive) values of a few mmag, while for ? Bootis stars - and for metal deficient A stars in general - we obtain negative values (as low as -12 mmag in one case). For the coolest CP2 stars with effective temperatures below about 8500 K, we obtain mild (~+10 mmag) to moderately large (~+30 mmag) flux depressions in agreement with observations. However, ?a values for slightly hotter members of the CP2 group (for which still Teff < 10000 K) are underestimated from these new models. The effect of the microturbulence parameter on the ?a index is revisited and its different role in various types of CP stars for reproducing the flux depression at 5200 Åis explained. We also provide reasons why models based on enhanced microturbulence and scaled solar abundance could not explain the observed flux depression for all types of CP stars. We discuss potential improvements of the current models including the possibility of still missing line opacities (unidentified and autoionization lines), modifications due to an explicit account of a global stellar magnetic field, and the effect of vertical abundance stratification.

Kupka, F.; Paunzen, E.; Iliev, I. Kh.; Maitzen, H. M.

2004-08-01

84

Guidelines for Community Relations Personnel. Criminal Justice Research. Prevention and Control of Collective Violence, Volume II.  

ERIC Educational Resources Information Center

|The objective of this study is to provide local law enforcement agencies with guidelines for the collection and dissemination of elements of information required for sound decision making in response to the threat or actual initiation of collective violence. Informal, semi-structured interviews in fourteen selected cities and six State police…

Callahan, W. Thomas; Knoblauch, Richard L.

85

69 FR 19436 - Proposed Data Collection; Comment Request Health Information National Trends Survey (HINTS) II  

Federal Register 2010, 2011, 2012, 2013

...telephone as the primary mode of data collection as well as [[Page...experiment with alternative modes of data collection (i.e., the Internet). Data will be used (1) to understand...3) to develop appropriate messages for the public about...

2004-04-13

86

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

Federal Register 2010, 2011, 2012, 2013

...an online voluntary training program to improve security in the chemical...supervisor. DHS will monitor program participation, success in training, and basic distribution...Security, National Protection and Programs Directorate, Office of...

2010-11-05

87

Information-collection request for: National Primary Drinking Water Regulations for inorganic chemicals. Phase 2, March 1989  

SciTech Connect

The Environmental Protection Agency (EPA), under the requirements of the Safe Drinking Water Act Section 1401 and 1412, P.L. 99-339, as amended in 1986, has proposed a National Primary Drinking Water Regulation (NPDWR) pertaining to the contamination of public-water systems by inorganic chemical contaminants. The proposed IOCs Rule includes information collection requirements for eight inorganic chemicals -- asbestos, barium, cadmium, chromium, mercury, nitrate, nitrite, and selenium. The information collection request analyzes the information burden imposed on public-water systems and States as a result of the regulation. EPA is proposing only to regulate source-related inorganics under this rule, as opposed to inorganics which predominately occur as corrosion by-products and naturally occurring copper and lead are analyzed in the RIA and ICR for lead and corrosion by-products. Note also that EPA has already promulgated a NPDWR for fluoride.

Not Available

1989-03-31

88

PRT Impact Study, PRE-PRT Phase. Volume II. Data Collection Procedure and Coding Manual.  

National Technical Information Service (NTIS)

The report describes the procedures utilized for collection of data on transportation demand and supply prior to the revenue operation of the Personal Rapid Transit (PRT) System in Morgantown, West Virginia. Most of the report is devoted to describing var...

S. E. G. Elias C. N. Redwine R. Trent J. M. Rovelstad A. K. Mallik

1976-01-01

89

Simultaneous determination of platinum(II) and palladium(II) by reversed phase high-performance liquid chromatography with spectrophotometric detection after collection on and elution from resin coated with dimethylglyoxal bis(4-phenyl-3-thisomicarbazone)  

Microsoft Academic Search

Amberlite XAD-7 resin coated with dimethylglyoxal bis(4-phenyl-3-thiosemicarbazone) (DMBS) was prepared and applied to the preconcentration of platinum(II) and palladium(II) from aqueous solution. Platinum(II) and palladium(II) were collected quantitatively on resin coated with the reagent (DMBS-XAD-7) from acidic solution in the presence of iodide ion by a bach method. The metal ions were then easily eluted from DMBS-XAD-7 as their DMBS

Suwaru Hoshi; Koki Higashihara; Mamiko Suzuki; Yasutoshi Sakurada; Kazuharu Sugawara; Masayuki Uto; Kunihiko Akatsuka

1997-01-01

90

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

91

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 used 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 optical kappa-epsilon turbulence model, and several additions to the spray model. The authors illustrate some of the new capabilities by means of example solutions.

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

1987-01-01

92

A new technology for harnessing the dye polluted water and dye collection in a chemical factory.  

PubMed

A new technology for harnessing the dye polluted water and dye collection was developed. It is based on the enhanced evaporation by using solar, wind and air temperature energy and additional heat-electric energy. It consists of four parts: (1) evaporation carrier system (evaporation carrier and frame for evaporation carrier) for polluted water; (2) polluted water circulating system (pumping-spraying-collecting); (3) heating system; (4) workshop with polluted water reservoir-tanks and rainfall prevention roof. The polluted water was (heated in case necessary) sprayed to the evaporation carrier system and the water was evaporated when it moved in the space and downward along the carrier mainly by using natural (solar, wind and air temperature energy). In case, when there is no roof for the carrier system, the polluted water can be stored in the reservoirs (storage volume for about 20 days). The first 10-25 mm rainfall also need to be stored in the reservoirs to meet the state standard for discharging wastewater. The dye may be collected at the surface in the reservoir-tanks and the crystallized salt may be collected at the bottom plate. The black-color wastewater released by the factory is no more discharged to the surface water system of Taihu Lake Basin. About 2 kg dye and 200 kg industrial salt may be collected from each tone of the polluted water. The non-pollution production of dye may be realized by using this technology with environmental, economical and social benefits. PMID:11590742

Pu, J P; Pu, P M; Hu, C H; Qian, J L; Pu, J X; Hua, J K

2001-04-01

93

Re-imagining Collectivities: The Mexican Japanese during World War II  

Microsoft Academic Search

\\u000aThe removal from the United States\\/Mexico borderlands of persons of Japanese descent during World War II resulted in great losses which, until now, have not been acknowledged by the Mexican or the United States government. Although their forced relocation is an event of great significance in the relations of the two countries involved in their displacement, the official narratives deny

Selfa Chew

2008-01-01

94

Initial chemical and biological characterization of hydrotreated solvent refined coal (SRC-II) liquids: a status report  

Microsoft Academic Search

This report presents the results of both chemical and biomedical research performed on a solvent refined coal (SRC-II) research material (distillate blend) which was produced by the pilot plant facility at Fort Lewis, Washington. Samples of this distillate blend were subjected to research-scale hydrotreatment by Universal Oil Products, Inc., prior to chemical and biological analysis at PNL. The samples are

W. C. Weimer; B. W. Wilson; R. A. Pelroy; J. C. Craun

1980-01-01

95

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

96

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

97

Analysis of chemical abundances in planetary nebulae with [WC] central stars. II. Chemical abundances and the abundance discrepancy factor  

NASA Astrophysics Data System (ADS)

Aims: We present the abundance analysis of 12 planetary nebulae ionized by [WC]-type stars and weak-emission-line stars (wels) obtained from high-resolution spectrophotometric data. Our main aims are to determine the chemical composition of the nebulae and to study the behaviour of the abundance discrepancy problem (ADF) in this type of planetary nebulae. Methods: The detection of a large number of optical recombination lines (ORLs) and collisionally excited lines (CELs) from different ions (O+, O++, C++, C+3 and Ne++) were presented previously. Most of the ORLs were reported for the first time in these PNe, which increased the sample of PNe with detected faint ORLs. Ionic abundances were determined from the available CELs and ORLs, using previously determined physical conditions. Based on these two sets of ionic abundances, we derived the total chemical abundances in the nebulae using suitable ionization correction factors (when available). Results: In spite of the [WC] nature of the central stars, moderate ADF(O++) in the range from 1.2 to 4 were found for all the objects. We found that when the quality of the spectra is high enough, the ORLs O++/H+ abundance ratios obtained from different multiplets excited mainly by recombination are very similar. Possible dependence of ADFs on some nebular characteristics such as surface brightness and nebular diameter were analysed, but we found no correlation. Abundances derived from CELs were corrected by determining the t2 temperature fluctuation parameter. O abundances for PNe, derived from ORLs, are in general higher than the solar abundance. We derived the C/O ratio from ORLs and N/O and ?-element/O ratios from CELs and found that these PNe are, on average, richer in N and C than the average of the large PN samples. About half of our sample is C-rich (C/O > 1). The growth of ?-elements is correlated with the O abundance. Comparing the N/O and C /O ratios with those derived from stellar evolution models, we estimate that about half of our PNe have progenitors with initial masses similar to or larger than 4 M?. No correlation was found between the stellar [WC] type and the nebular chemical abundances. A rough O abundance gradient computed for our limited PN sample, compared with the gradient obtained for H ii regions, shows that there is a large dispersion in estimates of the PNe O abundance for a given Galactocentric distance. The PN gradient is flatter than that for H ii regions and at the solar distance and farther out, the PNe have a higher O abundance than H ii regions, similarly to what is found in other spiral galaxies. This fact has no convincing explanation so far. Based on data obtained at Las Campanas Observatory, Carnegie Institution.

García-Rojas, Jorge; Peña, Miriam; Morisset, Christophe; Delgado-Inglada, Gloria; Mesa-Delgado, Adal; Ruiz, María Teresa

2013-10-01

98

Metabolic profiling of GuanXin II prescription based on metabolic fingerprinting and chemical analysis.  

PubMed

A sensitive LC/MS method was established to investigate the in vivo metabolism of GuanXin II prescription, a five-component Chinese herbal medicine formulation. Rat plasma, bile, urine, and feces were collected and analyzed following oral administration of the water decoction. A total of 50 compounds were identified, including 17 prototypes and 33 metabolites underwent methylation, oxidation, hydrolysis, sulfate conjugation, glucuronide conjugation, and glutathion conjugation. In addition, the component herb of the formulation from which the metabolites were derived was also identified. Among the five component herbs, Rhizoma Chuanxiong, Flos Carthami, and Lignum Dalbergiae Odoriferae were actively metabolized, contributing 26 metabolites and 2 prototypes, while Radix Salviae Miltiorrhizae and Radix Paeoniae Rubra underwent less biotransformation, yielding 7 metabolites and 15 prototypes. This is the first study on the metabolic profile of GuanXin II prescription. The results could be valuable to elucidate the material basis of this formulated Chinese medicine. PMID:21094011

Qiao, Xue; Han, Jian; Xu, Man; Zhang, Zi-chuan; Ye, Min; Ye, Guan; Guo, De-an

2010-10-29

99

Relationships between chemical structure and rat repellency: II. compounds screened between 1950 and 1960  

USGS Publications Warehouse

Over 4,600 compounds, chiefly organic types, were evaluated using both a food acceptance test (Part A) and a barrier penetration bioassay (Part B), to correlate relationships between chemical structure and rodent repellency. These chemicals are indexed and classified according to the functional groups present and to the degree of substitution within their molecular structures. The results of reduction in food consumption for each compound appraised are calculated and their K values listed in Table 1. The repellent activities of the functional groups represented, alone or in combinations, are expressed in Table II by a Functional Group Repellency Index.. A ranking of these indices suggests that acyclic and heteroyclic compounds containing tri- or pentavalent nitrogen would be a parent compound of choice for synthesizing novel repellents. Other molecular arrangements, spatial configurations and combinations of functional groups are compared. There were 123 active, interesting or promising compounds included in the 699 having K values of 85 or greater, which were selected for the barrier appraisal study. These chemicals were formulated in selective solvents at several concentrations and applied to burlap. Small food bags were fashioned using the fabric impregnated with the candidate formulation, and exposed to rodent attack following storage periods of varying intervals. The results of these tests are listed in Table III. Again, those compounds containing nitrogen in the functional groupings indicated a high order of effectiveness. Several commercial patents covering rodent repellents were issued using the data from the food acceptance and barrier studies. Organizations and cooperators which supplied samples for the program are listed in Appendix I. The Wiswesser cipher for compounds in Table I is used in Appendix II to facilitate location of chemicals by sample code number as they appear under the index headings, and for computer storage and analysis.

Bowles, Walter A.; Adomaitis, V.A.; DeWitt, J.B.; Pratt, J.J.,Jr.

1974-01-01

100

Relationships between chemical structure and rat repellency. II. Compounds screened between 1950 and 1960  

USGS Publications Warehouse

Over 4,600 compounds, chiefly organic types, were evaluated using both a food acceptance test (Part A) and a barrier penetration bioassay (Part B), to correlate relationships between chemical structure and rodent repellency.These chemicals are indexed and classified according to the functional groups present and to the degree of substitution within their molecular structures. The results of reduction in foot consumption for each compound appraised are calculated and their K values listed in Table I.The repellent activities of the functional groups represented, alone or in combinations, are expressed in Table II by a Functional Group Repellency Index. A ranking of these indices suggests that acyclic and heteroyclic compounds containing tri- or pentavalent nitrogen would be a parent compound of choice for synthesizing novel repellents. Other molecular arrangements, spatial configurations and combinations of functional groups are compared.There were 123 active, interesting or promising compounds included in the 699 having K values of 85 or greater, which were selected for the barrier appraisal study. These chemicals were formulated in selective solvents at several concentrations and applied to burlap. Small foot bags were fashioned using the fabric impregnated with the candidate formulation, and exposed to rodent attack following storage periods of varying intervals. The results of these tests are listed in Table III. Again, those compounds containing nitrogen in the functional groupings indicated a high order of effectiveness. Several commercial patents covering rodent repellents were issued using the data from the food acceptance and barrier studies.Organizations and cooperators which supplied samples for the program are listed in Appendix I. The Wiswesser cipher for compounds in Table I is used in Appendix II to facilitate location of chemicals by sample code number as they appear under the index headings, and for computer storage and analysis.

Bowles, W. A.; Adomaitis, V. A.; DeWitt, J. B.; Pratt, J. J., Jr.

1974-01-01

101

Chemical speciation of size-segregated floor dusts and airborne magnetic particles collected at underground subway stations in Seoul, Korea.  

PubMed

Previous studies have reported the major chemical species of underground subway particles to be Fe-containing species that are generated from wear and friction processes at rail-wheel-brake and catenaries-pantographs interfaces. To examine chemical composition of Fe-containing particles in more details, floor dusts were collected at five sampling locations of an underground subway station. Size-segregated floor dusts were separated into magnetic and non-magnetic fractions using a permanent magnet. Using X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDX), iron metal, which is relatively harmless, was found to be the dominating chemical species in the floor dusts of the <25 ?m size fractions with minor fractions of Mg, Al, Si, Ca, S, and C. From SEM analysis, the floor dusts of the <25 ?m size fractions collected on railroad ties appeared to be smaller than 10 ?m, indicating that their characteristics should somewhat reflect the characteristics of airborne particles in the tunnel and the platform. As most floor dusts are magnetic, PM levels at underground subway stations can be controlled by removing magnetic indoor particles using magnets. In addition, airborne subway particles, most of which were smaller than 10 ?m, were collected using permanent magnets at two underground subway stations, namely Jegi and Yangjae stations, in Seoul, Korea. XRD and SEM/EDX analyses showed that most of the magnetic aerosol particles collected at Jegi station was iron metal, whereas those at Yangjae station contained a small amount of Fe mixed with Na, Mg, Al, Si, S, Ca, and C. The difference in composition of the Fe-containing particles between the two subway stations was attributed to the different ballast tracks used. PMID:22381374

Jung, Hae-Jin; Kim, BoWha; Malek, Md Abdul; Koo, Yong Sung; Jung, Jong Hoon; Son, Youn-Suk; Kim, Jo-Chun; Kim, HyeKyoung; Ro, Chul-Un

2012-02-11

102

Direct Collection of Aerosols by Electrostatic Classification for Size-Resolved Chemical Analysis  

Microsoft Academic Search

The performance of an inlet for the size-resolved collection of aerosols onto a heating filament for subsequent thermal desorption is presented. The device resembles a cylindrical Differential Mobility Analyzer (DMA) in that a sample flow is introduced around the periphery of the annulus between two concentric cylinders, and charged particles migrate inward towards the inner cylinder in the presence of

Denis J. Phares; Sonya Collier

2010-01-01

103

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

104

Search for extraterrestrial point sources of high energy neutrinos with AMANDA-II using data collected in 2000-2002  

SciTech Connect

The results of a search for point sources of high energy neutrinos in the northern hemisphere using data collected by AMANDA-II in the years 2000, 2001, and 2002 are presented. In particular, a comparison with the single-year result previously published shows that the sensitivity was improved by a factor of 2.2. The muon neutrino flux upper limits on selected candidate sources, corresponding to an E{sub {nu}}{sup -2} neutrino energy spectrum, are included. Sky grids were used to search for possible excesses above the background of cosmic ray induced atmospheric neutrinos. This search reveals no statistically significant excess for the three years considered.

Ackermann, M.; Bernardini, E.; Boersma, D.J.; Boeser, S.; Hauschildt, T.; Kowalski, M.; Leich, H.; Leuthold, M.; Nahnhauer, R.; Resconi, E.; Schlenstedt, S.; Spiering, C.; Steffen, P.; Sulanke, K. H.; Tarasova, O.; Walter, M.; Wischnewski, R.; Wissing, H. [DESY, D-15735, Zeuthen (Germany); Ahrens, J.; Becka, T. [Institute of Physics, University of Mainz, Staudinger Weg 7, D-55099 Mainz (Germany)] [and others

2005-04-01

105

Aerosols Collected at a Tropical Marine Environment: Size-Resolved Chemical Composition Using IC, TOC, and Thermal-Optical Analyses  

NASA Astrophysics Data System (ADS)

Size-resolved chemical characterization was performed on aerosol samples collected at two different marine sites in the tropics: Dian Point (DP), Antigua and Cape San Juan (CSJ), Puerto Rico. A 13-stage Dekati low- pressure impactor (Dp 0.1 to 10 ?m), a 10-stage micro-orifice uniform deposit impactor (Dp 0.054 to 18 ?m), and stacked-filter units (Dp < 1.7 ?m) were used to collect the samples. Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO2-, NO3-, SO42-, acetate, formate, malonate, and oxalate were determined using ion chromatography (IC). Thermal-optical analysis (TOA) was used to determine the concentrations of aerosol total carbon (TC), organic carbon (OC), and elemental carbon (EC). Five-day back trajectories calculated using NOAA's HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) model identified air masses coming from the North Atlantic (maritime air), Northwest Africa (desert dust), and North America (anthropogenic pollution). Size-resolved chemical characterization of aerosol samples using IC and TOA confirmed that aerosols become aged as they are transported to the Caribbean and their composition depends on the air mass origin. Gravimetric analyses showed that average fine mass concentrations for CSJ station were higher than for DP station (CSJ: 1.9 ?g m-3; DP: 1.2 ?g m-3). The aerosol chemical composition changed with air masses of different origin and with different pollution levels. In both locations the predominant water-soluble ions in the fine aerosol fraction were Cl-, Na+, and SO42-. Sulphate was observed in higher concentrations during the polluted case and particulate organic matter concentrations were higher for the maritime case. During desert dust events an increase in Ca2+ and Mg2+ of 4 and 2 times, respectively, was observed mainly in the coarse mode. Results for the size-resolved chemical composition and complete aerosol chemical apportionment including the residual mass will be presented.

Morales-García, F.; Mayol-Bracero, O. L.; Repollet-Pedrosa, M.; Kasper-Giebl, A.; Ramírez-Santa Cruz, C.; Puxbaum, H.

2009-05-01

106

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.

107

Collective Modes in Quantum Lattice or Three-Dimensional XY Model. II  

Microsoft Academic Search

An external field is applied to the XY model which was studied in a previous paper. With the help of Mori's memory function formalism, two types of collective modes are obtained. One of those, which was previously pointed out to correspond to the first sound in superfluid helium, survives at the critical temperature T_c. The other is a new mode,

Tosizumi Aoki; Shigeo Homma; Huzio Nakano

1982-01-01

108

Chemical characteristics of rainwater collected at a western site of Jordan  

Microsoft Academic Search

A comprehensive study on the chemical composition of rainwater was carried out from October 2006 to May 2007 in Ghore El-Safi area western side of Jordan nearby the Dead Sea. Rainwater samples were analyzed for major ions (Ca2+, Mg2+, K+, Na+, NH4+, HCO3?, Cl?, NO3? and SO42?) and trace metals (Fe, Al, Zn, Pb, Cu, and Cd). The highest concentration

Omar Ali. Al-Khashman

2009-01-01

109

Galactic Chemical Evolution & the Hot Star - H II Region Connection in NGC6822  

NASA Astrophysics Data System (ADS)

H II regions provide fundamental data about heavy element abundances that constrain galactic chemical evolution (GCE) models. We propose to use Spitzer/IRS to follow up on our Spitzer observations of M83 and M33 H II regions. We will measure S IV 10.5, Ne II 12.8, Ne III 15.6, S III 18.7, & H7-6 12.4 micron cospatially with IRS/SH. By measuring all the major ionic states of Ne and S in H II regions with an H line, there is a unique opportunity to estimate S3+/S++, Ne++/Ne+, Ne/H, S/H, & Ne/S ratios and test if they vary with galactocentric radius (R_G). The high Ne/S ratios we derived for M83 are likely upper limits due to our estimate of the S abundance not accounting for S+ or dust. The M33 H II regions have much lower metallicity and higher ionization, leading to a truer total S abundance & a Ne/S close to the Orion Nebula value 14. The H II regions in the nearby, dwarf irregular galaxy NGC6822 are both low metallicity (O/H ~3.5x lower than Solar) and high ionization, allowing a reliable derivation of gas-phase Ne/S. The solar Ne abundance is very controversial, with much evidence pointing to a higher Ne value than the current Ne/S~5. NGC6822 observations will test how robust and universal the ratio of ~14 is. Such a finding will place important constraints upon GCE models. Our derivation of ionic abundances from Spitzer data depends on nebular models, which rely on the spectral energy distribution (SED) which comes from stellar atmosphere models. From our M83 and M33 data, we derive / & / vs. / ratios for the various H II regions and compare with theoretical loci, which show a factor >10 spread in y at a given x. The data points best follow the trend of the loci using the supergiant SEDs of Pauldrach, who will compute a set of atmosphere models with metallicity similar to that of NGC6822. Data for a third galaxy with a very different history and gas content will further validate whether or not any SED set preferentially fits the nebular observations.

Rubin, Robert; Buckalew, Brent; Colgan, Sean; Dufour, Reginald; Erickson, Edwin; Haas, Michael; Janet, Simpson; Pauldrach, Adalbert

2007-05-01

110

Chemical and isotopic properties and origin of coarse airborne particles collected by passive samplers in industrial, urban, and rural environments  

NASA Astrophysics Data System (ADS)

Passive air samplers have been installed in industrial, urban, rural and remote forested environments in order to collect coarse airborne particles for subsequent chemical characterization. To identify principal polluting sources, isotopic tracers, such as Sr, Nd and Pb isotopic ratios, have been used. The mass deposition rates (MDRs) of trace metals, determined for each of the studied environments, clearly indicate that industrial and traffic sites are especially affected by air pollution. Elements such as V, Pb, Fe, Cr, Co, Mo, Cd, Ni, As, Sb and Zn are notably enriched in samples from industrial zones, whereas V, Mn, Ba, Sr, Al, U, Th, rare earth elements (REE), Zr, Y, Cs, Rb, Sb, Sn and Cu are principal components of the airborne particles collected close to areas influenced by heavy traffic. The chemical/isotopic baseline composition derived from the airborne particles is the result of mixing of particles from different industrial sources, traffic and fertilizers. The monthly analysis of trace-metal MDRs of the collected airborne particle samples from different stations around the industrial zone allows for the detection of distinct atmospheric dust-deposition events during the year, characterized by high MDRs. "Natural" dusts from regional soil re-suspension, including from more distant regions like the Sahara desert, might overprint the regional atmospheric baseline composition, as suggested by trace metal trajectories in ternary diagrams and by Sr, Nd and Pb isotope data.

Guéguen, Florence; Stille, Peter; Dietze, Volke; Gieré, Reto

2012-12-01

111

Total chemical synthesis of enzymatically active human type II secretory phospholipase A2  

PubMed Central

Human group II secretory phospholipase A2 (sPLA2) is an enzyme found in the ? granules of platelets and at inflammatory sites. Although its physiological function is unclear, sPLA2 can inhibit blood coagulation reactions independent of its lipolytic action. To study the molecular basis of PLA2 activities, we developed a total chemical synthesis of sPLA2 by chemical ligation of large unprotected peptides. The synthetic segments PLA2-(1–58)-?COSCH2COOH and PLA2-(59–124) were prepared by stepwise solid-phase peptide synthesis and ligated to yield a peptide bond between Gly58 and Cys59. The 124-residue polypeptide product (mass: 13,920 ± 2 Da) was folded to yield one major product (mass: 13,905 ± 1 Da), the loss of 15 ± 3 Da reflecting the formation of seven disulfide bonds. Circular dichroism studies of synthetic sPLA2 showed ?-helix, ?-structure, and random coil contents consistent with those found in the crystal structure of sPLA2. Synthetic sPLA2 had kcat and Km values identical to those of recombinant sPLA2 for hydrolysis of 1,2-bis(heptanoylthio)-phosphatidylcholine. Synthetic sPLA2, like recombinant sPLA2, inhibited thrombin generation from prothrombinase complex (factors Xa, V, II, Ca2+, and phospholipids). In the absence of phospholipids, both synthetic and recombinant sPLA2 inhibited by 70% prothrombin activation by factors Xa, Va, and Ca2+. Thus, synthetic sPLA2 is a phospholipid-independent anticoagulant like recombinant or natural sPLA2. This study demonstrates that chemical synthesis of sPLA2 yields a fully active native-like enzyme and offers a straightforward tool to provide sPLA2 analogs for structure–activity studies of anticoagulant, lipolytic, or inflammatory activities.

Hackeng, Tilman M.; Mounier, Carine M.; Bon, Cassian; Dawson, Philip E.; Griffin, John H.; Kent, Stephen B. H.

1997-01-01

112

Collective synthesis of several 2,7'-cyclolignans and their correlation by chemical transformations.  

PubMed

Collective synthesis of anti-malarial 2,7'-cyclolignans has been stereoselectively achieved employing (±)-cyclogalgravin () as a linchpin through a series of functional group conversions, including redox reactions. Interestingly, can be correlated with the neolignan (±)-kadangustin J () isolated from a different plant source, through a highly efficient dehydrative cyclization reaction with excellent diastereotopic differentiation of the veratryl group and concomitant construction of the C1-C7 bond. It is noteworthy that the first total synthesis of stereodivergent (±)-8,8'-epi-aristoligone (), (±)-8'-epi-aristoligone (), (±)-8'-epi-8-OH-aristoligone () and (±)-8'-epi-aristoligol () was demonstrated. PMID:24097210

Peng, Yu; Luo, Zhen-Biao; Zhang, Jian-Jian; Luo, Long; Wang, Ya-Wen

2013-10-16

113

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

2013-03-26

114

Collective retention and transmission of chemical signals in a social insect  

NASA Astrophysics Data System (ADS)

Social insect colonies exhibit highly coordinated responses to ecological challenges by acquiring information that is disseminated throughout the colony. Some responses are coordinated directly from the signals produced by individuals that acquired the information. Other responses may require information to be transferred indirectly through a third party, thereby requiring colony-wide retention of information. Social insects use colony signature odours to distinguish between nestmates and non-nestmates, and the level of aggression between non-nestmates typically varies according to the distance between colonies and thus their history of interactions. Such coordinated, colony-specific responses may require information about particular odours to be disseminated and retained across the colony. Our field experiments with weaver ants reveal colony-wide, indirect acquisition and retention of the signature odours of a different colony with which they had experienced aggression. These data highlight the significance of interaction history and suggest the presence of a collective memory.

Gill, Katherine P.; van Wilgenburg, Ellen; Taylor, Peter; Elgar, Mark A.

2012-03-01

115

Chemical composition and biological activity of Conyza bonariensis essential oil collected in Mérida, Venezuela.  

PubMed

The essential oil from aerial parts of Conyza bonariensis (L) Cronquist collected in Mérida was obtained by hydrodistillation and analysed by GC/MS. The major components were trans-beta-farnesene (37.8%), trans-ocimene (20.7%) and beta-sesquiphellandrene (9.8%). Cytotoxicity assay was also performed with the essential oil against HeLa (cervix carcinoma), A-459 (lung carcinoma) and MCF-7 (breast adenocarcinoma) human cell lines and against normal Vero cells (African green monkey kidney) with IC50 values ranging from 1.4 to 45.8 microg/mL. Additionally, the essential oil presented a significant bactericidal effect against Bacillus cereus, while a moderate activity was observed against Staphylococcus epidermidis and Candida albicans. PMID:24079198

Araujo, Liliana; Moujir, Laila M; Rojas, Janne; Rojas, Luis; Carmona, Juan; Rondón, María

2013-08-01

116

Chemical characterization of aerosol collected at Mt. Yulong in wintertime on the southeastern Tibetan Plateau  

NASA Astrophysics Data System (ADS)

In order to evaluate the chemical composition of aerosol on the southeastern Tibetan Plateau, aerosol samples were acquired at Mt. Yulong during January to February, 2010. Eighteen elements (Al, Si, P, S, Ca, Ti, K, Cr, Mn, Fe, Ni, Zn, As, Br, Ba, Pb, Sb and Cu) and major water-soluble ions (SO42 -, NO3-, Cl-, Na+, NH4+, K+, Mg2 +, and Ca2 +) were detected. The results show that Ca, Fe, Al, Si, S, K and Ti are major elements which mainly originate from crustal material, while SO42 - and Ca2 + are the dominant anion and cation in the samples, respectively. Results of ion analysis indicate that our samples are alkaline and that the main compounds present are CaCO3, (NH4)2SO4, and CaSO4. The enrichment factors (EFs) determined for As, Br, Ca, Cu, S, Pb and Zn are greater than 10; in particular, EFs for As and Br are above 100. However, the high EF for As could be caused by crustal sources because the high level of As enrichment can be found commonly on the Tibetan Plateau. Analyses including Scanning Electron Microscope (SEM) observations, EF determinations, backward trajectories and correlation coefficients reveal that Al, Fe, Ca, Ti, Mn, Fe, K and Mg2 + mainly originate from crustal sources; Pb, Br, Cu, Ni, Zn and Sb come mainly from traffic-related emissions; and biomass burning influences Cl-, Br, S and P.

Zhang, Ningning; Cao, Junji; Ho, Kinfai; He, Yuanqing

2012-04-01

117

Comparison of remote consequences in Taraxacum officinale seed progeny collected in radioactively or chemically contaminated areas.  

PubMed

We carried out a comparative study of seed progeny taken from the dandelion (Taraxacum officinale s.l.) coenopopulations exposed for a long time to radioactive or chemical contamination originated from the East-Ural radioactive trace zone (EURT) or Nizhniy Tagil metallurgical combine impact zone (NTMC), respectively. Coenopopulations from EURT, NTMC and background areas significantly differ from each other with respect to the qualitative and quantitative composition of allozyme phenes. An analysis of clonal diversity showed the uniqueness of all coenopopulations in terms of their phenogenetics. P-generation seed viability was found to decrease in a similar manner as all types of the industrial stress increased. Studies of F (1)-generation variability in radio- and metal resistance by family analysis showed that seed progeny from EURT impact zone possessed high viability that, however, was accompanied by development of latent injuries resulting in low resistance to additional man-caused impacts. In F (1)-generation originated from NTMC zone, high seed viability was combined with increased resistance to provocative heavy metal and radiation exposure. No significant differences in responses to 'habitual' and 'new' factors, i.e. pre-adaptation effect, were found in samples from the contaminated areas. PMID:22661315

Pozolotina, Vera N; Antonova, Elena V; Bezel, Victor S

2012-06-02

118

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

119

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

NASA Astrophysics Data System (ADS)

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 (i.e., detrital and biogenic particles) in the older sedimentary unit (unit 1 in the West basin) represent 46% wt of the total, and that they were deposited between 23,000 and 15-12,000 years BP with a mass accumulation rate between 109 and 150 kg per thousand years per square metre. The muddy sediment in the upper part of the West basin core (units 2, 3, and 4) consists mainly of metalliferous particles which account for less than 15% wt of the mud, and yield a mass accumulation rate (130-162 kg/k.y./M 2) close to that of nonmetalliferous particles deposited simultaneously. Nonmetalliferous particles were probably the major source of Si and a significant source of Pb through dissolution in the brine system and diagenesis in the metalliferous mud. The metalliferous sediments in the upper unit of the South-West basin (unit U, 1100 cm) were deposited at the same time as those of the upper unit in the West basin (unit 4,335 cm). The calculated mass accumulation rate is about 700 kg/k.y./m 2 for unit U. The recent sediments of the South-West basin are more enriched in Zn and Cu, and more depleted in Mn relative to Fe than the contemporary sediments in the West basin, suggesting that the hydrothermal source has been in, or near, the South-West basin during the last 2,250 years. Assuming that a Salton Sea-like solution supplies all the Fe contained in the West basin metalliferous sedimentary pile, the mineralizing brine flowed at a minimum rate of 30 L/s. Except for the period of Mn-oxide deposition, the difference between the metal/Fe ratios in oxide-rich and sulphide-rich facies is attributed to changes in the chemical composition of the mineralizing fluid rather than to chemical processes acting in the brine system of the Atlantis II Deep.

Anschutz, Pierre; Blanc, Gérard

1995-10-01

120

Low-oxygen and chemical kinetic constraints on the geochemical niche of neutrophilic iron(II) oxidizing microorganisms  

Microsoft Academic Search

Neutrophilic iron oxidizing bacteria (FeOB) must actively compete with rapid abiotic processes governing Fe(II) oxidation and as a result have adapted to primarily inhabit low-O2 environments where they can more successfully compete with abiotic Fe(II) oxidation. The spatial distribution of these microorganisms can be observed through the chemical gradients they affect, as measured using in situ voltammetric analysis for dissolved

Gregory K. Druschel; David Emerson; R. Sutka; P. Suchecki; George W. Luther

2008-01-01

121

Mutagenic activity and chemical analysis of airborne particulates collected in Pisa (Italy)  

SciTech Connect

In the last few years there has been much concern about the problem connected to the exposure to mutagens present in the environment of industrialized countries. Particularly, the mutagenic activity of airborne particulate matter has been studied by many investigators and correlated with elevated lung cancer mortality rates. In most cases the Salmonella typhimurium/microsome test has been used for these studies. This short-term test, which is the most validated among the short-term genotoxicity tests, provides an important indication on the carcinogenic potential of environmental pollutants. That are complex mixtures containing a wide variety of compounds potentially capable of causing additive, antagonistic or synergistic genotoxic response in living organisms. Several studies have suggested that diverse factors, such as traffic and meteorological conditions, could affect the levels of pollutants in the air. In our work, we have investigated three different areas in Pisa, where the intensity and the kind of the road traffic were different. Airborne particles have been collected during a year and the genotoxic activity has been studied using TA98 and TA100 strains of Salmonella typhimurium. 20 refs., 1 fig., 3 tabs.

Vellosi, R.; Fiorio, R.; Rosellini, D.; Bronzetti, G. (Istituto di Mutagenesi e Differenziamento, Pisa (Italy)); Vannucchi, C.; Ciacchini, G.; Giaconi, V. (Unita Operativa Chimica Ambientale, Pisa (Italy)); Bianchi, F. (Istituto di Fisiologia Clinica, Pisa (Italy))

1994-03-01

122

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

123

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

124

Chemical Composition of Samples Collected from Waste Rock Dumps and Other Mining-Related Features at Selected Phosphate Mines in Southeastern Idaho, Western Wyoming, and Northern Utah.  

National Technical Information Service (NTIS)

This report provides chemical analyses for 31 samples collected from various phosphate mine sites in southeastern Idaho (25), northern Utah (2), and western Wyoming (4). The sampling effort was undertaken as a reconnaissance and does not constitute a char...

P. R. Moyle J. D. Causey

2001-01-01

125

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

126

Chemical characteristics of rainwater collected at a western site of Jordan  

NASA Astrophysics Data System (ADS)

A comprehensive study on the chemical composition of rainwater was carried out from October 2006 to May 2007 in Ghore El-Safi area western side of Jordan nearby the Dead Sea. Rainwater samples were analyzed for major ions (Ca 2+, Mg 2+, K +, Na +, NH 4+, HCO 3-, Cl -, NO 3- and SO 42-) and trace metals (Fe, Al, Zn, Pb, Cu, and Cd). The highest concentration of elements is observed at the beginning of the rainfall season when large amounts of dust accumulated in the atmosphere scavenged by rain. The majority of rainwater had a neutral or alkaline character as a result of neutralization caused by the alkaline local dusts which contain large amount of CaCO 3. The pH ranged from 4.8 to 8.2 with a mean value of 6.9 ± 0.65 which was in alkaline range considering 5.6 as the neutral pH of cloud water with atmospheric CO 2 equilibrium. In the total 35 rain events, only three events were observed in acidic range (< 5.6) which occurred after continuous rains. The equivalent concentration of components followed the order: Ca 2+ > HCO 3- > Cl - > Mg 2+ > NO 3- > SO 42- > NH 4+ > Na + > K +. Rainwater chemistry was analyzed using Factor Component Analysis to find the possible sources of the measured species. Three components that accounted for 84% of the total variance were extracted sea salts spray (Na+, Cl - and Mg 2+), and soil particles (natural origin), (Mg 2+, Ca 2+ and HCO 3-) and biomass burning (NH 4+). The results obtained in this study are compared with those other studies conducted at different sites in the world. In general, the results of this study suggested that rainwater chemistry is strongly influenced by local anthropogenic sources (potash factory and agricultural activities in Ghore El-Safi area) rather than natural and marine sources. The pollutants in rainwater samples were mainly derived from long distance transport, local industry and traffic sources.

Al-Khashman, Omar Ali.

2009-01-01

127

Chemical probes of the conformation of DNA modified by cis-diamminedichloroplatinum(II)  

SciTech Connect

The purpose of this work was to analyze at the nucleotide level the distortions induced by the binding of cis-diamminedichloroplatinum(II) (cis-DDP) to DNA by means of chemical probes. In order to test the chemical probes, experiments were first carried out on two platinated oligonucleotides. It has been verified by circular dichroism and gel electrophoresis that the binding of cis-DDP to an AG or to a GTG site within a double-stranded oligonucleotide distorts the double helix. The reactivity of the oligonucleotide platinated at the GTG site with chloroacetaldehyde, diethyl pyrocarbonate, and osmium tetraoxide, respectively, suggests a local denaturation of the double helix. The 5'G residue and the T residue within the adduct are no longer paired, while the 3'G residue is paired. The double helix is more distorted (but not denatured) at the 5' side of the adduct than at the 3' side. The reactivities of the chemical probes with six platinated DNA restriction fragments show that even at a relatively high level of platination only a few base pairs are unpaired but the double helix is largely distorted. No local denaturation has been detected at the GG sites separated from the nearest GG or AG sites by at least three base pairs. The AG sites separated from the nearest AG or GG sites by at least three base pairs do not denature the double helix locally when they are in the sequences puAG/pyTC. It is suggested that the distortion within these sequences is induced by adducts located further away along the DNA fragments, these sequences not being the major sites for the binding of cis-DDP.

Marrot, L.; Leng, M. (Centre de Biophysique Moleculaire, Orleans (France))

1989-02-21

128

The Chemically Controlled Synthesis of Dust in Type II-P Supernovae  

NASA Astrophysics Data System (ADS)

We study the formation of molecules and dust clusters in the ejecta of solar metallicity, Type II-P supernovae (SNe) using a chemical kinetic approach. We follow the evolution of molecules and small dust cluster masses from day 100 to day 1500 after explosion. We consider stellar progenitors with initial masses of 12, 15, 19, and 25 M ? that explode as SNe with stratified ejecta. The molecular precursors to dust grains comprise molecular chains, rings and small clusters of silica, silicates, metal oxides, sulfides and carbides, pure metals, and carbon, where the nucleation of silicate clusters is described by a two-step process of metal and oxygen addition. We study the impact of the 56Ni mass on the type and amount of synthesized dust. We predict that large masses of molecules including CO, SiO, SiS, O2, and SO form in the ejecta. We show that the discrepancy between the small dust masses detected at infrared wavelengths some 500 days post-explosion and the larger amounts of dust recently detected with Herschel in SN remnants can be explained by the non-equilibrium chemistry linked to the formation of molecules and dust clusters in the ejected material. Dust gradually builds up from small (~10–5 M ?) to large masses (~5 × 10–2 M ?) over a 5 yr period after explosion. Subsequent dust formation and/or growth is hampered by the shortage of chemical agents participating in the dust nucleation and the long timescale for accretion. The results highlight the dependence of the dust chemical composition and mass on the amount of 56Ni synthesized during the explosion. This dependence may partly explain the diversity of epochs at which dust forms in SNe. More generally, our results indicate that Type II-P SNe are efficient but moderate dust producers with an upper limit on the mass of synthesized dust ranging from ~0.03 to 0.09 M ?. Other dust sources must then operate at high redshift to explain the large quantities of dust present in young galaxies in the early universe.

Sarangi, Arkaprabha; Cherchneff, Isabelle

2013-10-01

129

Modeling of chemical interactions of fuel rod materials at high temperatures II. Investigation of downward relocation of molten materials  

Microsoft Academic Search

In Part II of the modeling of chemical interactions of fuel rod materials at high temperatures, qualitative results on the nature of Zr-rich melt oxidation and interactions with fuel rods allow further interpretation of the post-test examinations of structures (debris) formed in the CORA tests under more complicated conditions, namely during downward relocation of the melt. In this situation, the

M. S. Veshchunov; A. V. Palagin

1998-01-01

130

Variability of the He I ?5876 Å line in early type chemically peculiar stars. II  

NASA Astrophysics Data System (ADS)

To try to understand the behavior of helium variability in Chemically Peculiar stars, we continued our on-going observational campaign started by \\cite{catanzaro99}. In this paper we present a new set of time resolved spectroscopic observations of the He I 5876 Å line for a sample of 10 stars in the spectral range B3 - A2 and characterized by different overabundances. This line does not show variability in two stars: HD 77350 and HD 175156. It shows instead an equivalent width variation in phase with the Hipparcos light curve for two stars: HD 79158 and HD 196502. Antiphase variations have been found in 4 stars of our sample, namely: HD 35502, HD 124224, HD 129174 and HD 142990. Nothing we can say about HD 115735 because of the constancy of Hipparcos photometric data, while no phase relation has been observed for HD 90044. In the text we discuss the case of HD 175156, according to photometric calibration and our spectroscopic observations we rule out the membership of this star to the main sequence chemically peculiar stars. We confirm the results obtained in the previous paper for which phase relations between light, spectral and magnetic variations are not dependent on stellar spectral type or peculiarity subclass. Based on observations collected at stellar station ``M. G. Fracastoro'' of the Catania Astrophysical Observatory and on observations collected at Complejo Astrónomico El Leoncito (Casleo), which is operated under agreement between the Consejo Nacional de Investigationes Cientifícas y Técnicas (CONICET) and the National Universities of La Plata, Córdoba and San Juan.

Catanzaro, G.; Leone, F.

2003-07-01

131

Chemkin-II: A Fortran chemical kinetics package for the analysis of gas-phase chemical kinetics  

Microsoft Academic Search

This document is the user's manual for the second-generation Chemkin package. Chemkin is a software package for whose purpose is to facilitate the formation, solution, and interpretation of problems involving elementary gas-phase chemical kinetics. It provides an especially flexible and powerful tool for incorporating complex chemical kinetics into simulations of fluid dynamics. The package consists of two major software components:

R. J. Kee; F. M. Rupley; J. A. Miller

1989-01-01

132

Burnup calculations and chemical analysis of irradiated fuel samples studied in LWR-PROTEUS phase II  

SciTech Connect

The isotopic compositions of 5 UO{sub 2} samples irradiated in a Swiss PWR power plant, which were investigated in the LWR-PROTEUS Phase II programme, were calculated using the CASMO-4 and BOXER assembly codes. The burnups of the samples range from 50 to 90 MWd/kg. The results for a large number of actinide and fission product nuclides were compared to those of chemical analyses performed using a combination of chromatographic separation and mass spectrometry. A good agreement of calculated and measured concentrations is found for many of the nuclides investigated with both codes. The concentrations of the Pu isotopes are mostly predicted within {+-}10%, the two codes giving quite different results, except for {sup 242}Pu. Relatively significant deviations are found for some isotopes of Cs and Sm, and large discrepancies are observed for Eu and Gd. The overall quality of the predictions by the two codes is comparable, and the deviations from the experimental data do not generally increase with burnup. (authors)

Grimm, P.; Guenther-Leopold, I. [Paul Scherrer Inst., CH-5232 Villigen PSI (Switzerland); Berger, H. D. [AREVA NP GmbH, FEEP, Bunsenstrasse 43, D-91058 Erlangen (Germany)

2006-07-01

133

Chemkin-II: A Fortran Chemical Kinetics Package for the Analysis of Gas-Phase Chemical Kinetics.  

National Technical Information Service (NTIS)

This document is the user's manual for the second-generation Chemkin package. Chemkin is a software package whose purpose is to facilitate the formation, solution, and interpretation of problems involving elementary gas-phase chemical kinetics. It provide...

R. J. Kee F. M. Rupley J. A. Miller

1989-01-01

134

Extragalactic Chemical Abundances: Do H II Regions and Young Stars Tell the Same Story? The Case of the Spiral Galaxy NGC 300  

NASA Astrophysics Data System (ADS)

We have obtained new spectrophotometric data for 28 H II regions in the spiral galaxy NGC 300, a member of the nearby Sculptor Group. The detection of several auroral lines, including [O III] ?4363, [S III] ?6312, and [N II] ?5755, has allowed us to measure electron temperatures and direct chemical abundances for the whole sample. We determine for the first time in this galaxy a radial gas-phase oxygen abundance gradient based solely on auroral lines, and obtain the following least-square solution: 12 + log(O/H) = 8.57(±0.02) - 0.41(±0.03)R/R 25, where the galactocentric distance is expressed in terms of the isophotal radius R 25. The characteristic oxygen abundance, measured at 0.4 × R 25, is 12 + log(O/H) = 8.41. The gradient corresponds to -0.077 ± 0.006 dex kpc-1, and agrees very well with the galactocentric trend in metallicity obtained for 29 B and A supergiants in the same galaxy, -0.081 ± 0.011 dex kpc-1. The intercept of the regression for the nebular data virtually coincides with the intercept obtained from the stellar data, which is 8.59(±0.05). This allows little room for depletion of nebular oxygen onto dust grains, although in this kind of comparison we are somewhat limited by systematic uncertainties, such as those related to the atomic parameters used to derive the chemical compositions. We discuss the implications of our result with regard to strong-line abundance indicators commonly used to estimate the chemical compositions of star-forming galaxies, such as R 23. By applying a few popular calibrations of these indices based on grids of photoionization models on the NGC 300 H II region fluxes, we find metallicities that are higher by 0.3 dex (a factor of 2) or more relative to our nebular (Te based) and stellar ones. We detect Wolf-Rayet stellar emission features in ~1/3 of our H II region spectra, and find that in one of the nebulae hosting these hot stars the ionizing field has a particularly hard spectrum, as gauged by the "softness" parameter ? = (O+/O++)/(S+/S++). We suggest that this is related to the presence of an early WN star. By considering a larger sample of extragalactic H II regions we confirm, using direct abundance measurements, previous findings of a metallicity dependence of ?, in the sense that softer stellar continua are found at high metallicity. Based on observations collected at the European Southern Observatory, Chile, under program 077.B-0269.

Bresolin, Fabio; Gieren, Wolfgang; Kudritzki, Rolf-Peter; Pietrzy?ski, Grzegorz; Urbaneja, Miguel A.; Carraro, Giovanni

2009-07-01

135

Chemical composition and hygroscopic properties of size-segregated aerosol particles collected at the Adriatic coast of Slovenia.  

PubMed

The chemical composition as well as the water uptake characteristics of aerosols was determined in size-segregated samples collected during November 2002 on the Slovenian coast. Major ions, water-soluble organic compounds (WSOC), short-chain carboxylic acids and trace elements were determined in the water-soluble fraction of the aerosol. Total aerosol black carbon (BC) was measured from filter samples. Our results showed that the origin of air masses is an important factor that controls the variation in the size distribution of the main components. Very high concentrations of WSOC as well as higher concentrations of BC were found under mostly continental influence. Besides the main ionic species (SO4(2-), NH4(+), K+) in the finest size fraction (0.17-0.53 microm), the concentration of NO3(-) was also high. The difference between the two different air mass origins is particularly expressed for Cl-, Na+, Mg2+ and Ca2+ determined in particles larger than 1.6 microm. As expected, a very good correlation was found between Na+ and Cl-. A good correlation was found between sea salt elements and elements of crustal origin (Na+, Cl-, Mg2+, Ca2+, Sr). A good relationship between typical anthropogenic tracers (K, V and Pb) was also observed. The mass growth factors, for all size fractions of aerosols collected under continental influence were very low (maximum 2.23 at 94%, 1.6-5.1 microm), while under marine influence the mass growth factors increased significantly with the particle size. At 97% humidity, the mass growth factors were 6.95 for the size fraction 0.53-1.6 microm and 9.78 for larger particles (1.6-5.1 microm). PMID:16289211

Tursic, Janja; Podkrajsek, Bostjan; Grgi?, Irena; Ctyroky, Peter; Berner, Axel; Dusek, Ulrike; Hitzenberger, Regina

2005-11-09

136

Synthesis, physico-chemical investigations of Co(II), Ni(II) and Cu(II) complexes and their in vitro microbial, cytotoxic, DNA cleavage studies.  

PubMed

A series of metal complexes of cobalt(II), nickel(II), and copper(II) have been synthesized with newly derived biologically active ligands. These ligands were synthesized by the condensation of 2-amino-4-phenyl-1,3-thiazole with 8-formyl-7-hydroxy- 4-methylcoumarin. The probable structure of the complexes has been proposed on the basis of analytical and spectroscopic data (IR, UV-Vis, ESR, FAB-mass, and thermoanalytical). Electrochemical study of the complexes is also reported. Elemental analysis of the complexes confined them to stoichiometry of the type ML(2).2H(2)O [M = Co(II), Ni(II), and Cu(II)]. The Schiff base and its metal(II) complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Staphylococcus pyogenes, and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Aspergillus flavus, and Cladosporium) by the MIC method. The brine shrimp bioassay was carried out to study their in vitro cytotoxic properties, and also the Schiff base and its metal(II) complexes have been studied for DNA cleavage. PMID:20370554

Bagihalli, Gangadhar B; Patil, Sangamesh A

2010-06-01

137

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

138

Chemical and thermal reduction of thin films of copper (II) oxide and copper (I) oxide  

NASA Astrophysics Data System (ADS)

Chemical and thermal reduction of copper oxide thin films (~20 Å) has been studied with x-ray photoelectron spectroscopy (XPS) and temperature programmed desorption (TPD) for application in microelectronic device interconnects. XPS showed that copper (I) oxide (Cu2O) and copper (II) oxide (CuO) were reduced to copper metal at 400 K within a 30 min exposure to deuterium atoms (D*) and molecules at 1×10-4 Torr. Similarly, XPS showed that Cu2O was reduced to copper metal at 400 K within a 30 min exposure to methyl radicals (CH3*) and acetone molecules at 1×10-4 Torr. After D* exposure, TPD showed O leaves the Cu2O surface as D2O from 400 K to 700 K with a peak desorption temperature of 510 K. After CH3* exposure, TPD showed O leaves the Cu2O surface as CO2 over a range from 400 to 700 K with a peak temperature at 590 K. With carbon impurity below the XPS detection limit, thermal reduction of CuO to Cu2O was verified by XPS near 890 K. TPD experiments showed that O leaves the CuO surface as O2 at 890 K. Without surface C, thermal reduction of Cu2O was not observed up to 1073 K. Reduction of Cu2O without reactive radical species (D* or CH3*) was negligible. These results suggest that thin films of copper oxide can be reduced at 400 K with D* and CH3*.

Kirsch, P. D.; Ekerdt, J. G.

2001-10-01

139

Chemical modification of silica gel with synthesized new Schiff base derivatives and sorption studies of cobalt (II) and nickel (II)  

NASA Astrophysics Data System (ADS)

In this study, three Schiff base ligands and their complexes were synthesized and characterized by infrared spectroscopy (IR), thermogravimetric analyses (TGA), nuclear magnetic resonance (NMR), elemental analysis and magnetic susceptibility apparatuses. Silica gel was respectively modified with Schiff base derivatives, (E)-2-[(2-chloroethylimino)methyl]phenol, (E)-4-[(2-chloroethylimino)methyl]phenol and N, N'-[1,4-phenilendi(E)methylidene]bis(2-chloroethanamine), after silanization of silica gel by (3-aminopropyl)trimethoxysilane (APTS) by using a suitable method. Characterization of the surface modification was also performed with IR, TGA and elemental analysis. The immobilized surfaces were used for Co(II) and Ni(II) sorption from aqueous solutions and values of sorption were detected by atomic absorption spectrometer (AAS).

Kursunlu, Ahmed Nuri; Guler, Ersin; Dumrul, Hakan; Kocyigit, Ozcan; Gubbuk, Ilkay Hilal

140

Removal of Pb(II) from aqueous solutions using activated carbon from Sea-buckthorn stones by chemical activation  

Microsoft Academic Search

Two series of activated carbon have been prepared by chemical activation of Sea-buckthorn stones with phosphoric acid and zinc chloride for the removal of Pb(II) ions from aqueous solutions. To characterize the adsorptive characteristics of produced active carbon, surface area was calculated using the standard Brunauer–Emmet–Teller method. The microstructures of the resultant activated carbon were observed by scanning electron micrographs.

Sayed Zia Mohammadi; Mohammad Ali Karimi; Daryoush Afzali; Fatemeh Mansouri

2010-01-01

141

Effect of structural and chemical parameters on magnetic coupling in hydroxo-bridged Cu(II) dimer  

Microsoft Academic Search

The influence of various structural and chemical parameters on magnetic coupling in model hydroxo-bridged Cu(II) dimers has been analyzed using the density functional theory and the broken symmetry approach. These parameters, such as the environment around copper atom, the electro negativity of the nonbridging ligands, the Cu–O–Cu angle, the Cu–O distance, the out-of-plane displacement of hydroxo group and the hinge

Haiquan Hu; Yongjun Liu; Dongju Zhang; Chengbu Liu

2001-01-01

142

Electrocatalytic reduction of nitrite at a carbon fiber microelectrode chemically modified by palladium(II)-substituted Dawson type heptadecatungstodiphosphate  

Microsoft Academic Search

A new type of chemically modified electrode (CME) was fabricated by electrodeposition of palladium(II)-substituted Dawson type heptadecatungstodiphosphate, K8[P2W17O61Pd(H2O)] (abbreviated as P2W17Pd in the following), onto a carbon fiber microelectrode (CFME). A pair of waves was observed on the P2W17Pd CFME, which is ascribed to the redox process of the palladium center in the heteropolytungstate. After continuous potential scanning for 30

Wenliang Sun; Song Zhang; Xinrong Lin; Litong Jin; Songling Jin; Jiaqi Deng; Jilie Kong

1999-01-01

143

Electrospray organometallic chemical vapor deposition—A novel technique for preparation of II–VI quantum dot composites  

Microsoft Academic Search

A novel technique combining electrospray and organometallic chemical vapor deposition (OMCVD) has been developed for the synthesis of new II–VI quantum dot composites. CdSe nanocrystals (quantum dots) of selected size are dispersed in a pyridine\\/acetonitrile mixture. The nanocrystals are transferred by electrospray into the growth zone of an OMCVD reactor and codeposited on a ZnSe matrix grown from hydrogen selenide

M. Danek; K. F. Jensen; C. B. Murray; M. G. Bawendi

1994-01-01

144

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

145

Relationships between Chemical Structure and Rat Repellency. II. Compounds Screened Between 1950 and 1960.  

National Technical Information Service (NTIS)

Over 4,600 compounds, chiefly organic types, were evaluated using both a food acceptance test and a barrier penetration bioassay to correlate relationships between chemical structure and rodent repellency. These chemicals are indexed and classified accord...

J. B. DeWitt J. J. Pratt V. A. Adomaitis W. A. Bowles

1974-01-01

146

TECHNICAL BASIS FOR NARCOTIC CHEMICALS AND POLYCYCLIC AROMATIC HYDROCARBON CRITERIA. II. MIXTURES AND SEDIMENTS  

Microsoft Academic Search

A method is presented for developing sediment quality guidelines (SQG) for narcotic chemicals in general and polycyclic aromatic hydrocarbons (PAHs) in particular. The guidelines can be applied to any individual or mixture of narcotic chemicals including PAHs using only the chemical's octanol\\/water partition coefficient. They are derived using the final chronic values for type I narcotics developed from a database

Dominic M. Di Toro; Joy A. McGrath

2000-01-01

147

Decision-Analytic Aid for Collection and Allocation Planning (CAPS): User's Guide for the Apple II Plus Microcomputer.  

National Technical Information Service (NTIS)

This manual describes an aid based on decision-analytic techniques for preparing the collection plan and allocating collection assets. Dealing with one essential element of information at a time, the aid will encourage the analyst to identify systematical...

J. Hall R. Phelps U. Shvern

1984-01-01

148

Radiation thermo-chemical models of protoplanetary disks. II. Line diagnostics  

NASA Astrophysics Data System (ADS)

Aims: In this paper, we explore the diagnostic power of the far-IR fine-structure lines of [Oi] 63.2 ?m, 145.5 ?m, [Cii] 157.7 ?m, as well as the radio and sub-mm lines of CO J=1-0, 2-1 and 3-2 in application to disks around Herbig Ae stars. We aim at understanding where the lines originate from, how the line formation process is affected by density, temperature and chemical abundance in the disk, and to what extent non-LTE effects are important. The ultimate aim is to provide a robust way to determine the gas mass of protoplanetary disks from line observations. Methods: We use the recently developed disk code ProDiMo to calculate the physico-chemical structure of protoplanetary disks and apply the Monte-Carlo line radiative transfer code Ratran to predict observable line profiles and fluxes. We consider a series of Herbig Ae type disk models ranging from 10-6 M_? to 2.2 × 10-2 M_? (between 0.5 and 700 AU) to discuss the dependency of the line fluxes and ratios on disk mass for otherwise fixed disk parameters. This paper prepares for a more thorough multi-parameter analysis related to the Herschel open time key program Gasps. Results: We find the [Cii] 157.7 ?m line to originate in LTE from the surface layers of the disk, where The total emission is dominated by surface area and hence depends strongly on disk outer radius. The [Oi] lines can be very bright (>10-16 W/m2) and form in slightly deeper and closer regions under non-LTE conditions. For low-mass models, the [Oi] lines come preferentially from the central regions of the disk, and the peak separation widens. The high-excitation [Oi] 145.5 ?m line, which has a larger critical density, decreases more rapidly with disk mass than the 63.2 ?m line. Therefore, the [Oi] 63.2 ?m/145.5 ?m ratio is a promising disk mass indicator, especially as it is independent of disk outer radius for R_out>200 AU. CO is abundant only in deeper layers AV ? 0.05. For too low disk masses (M_disk?10-4~M_?) the dust starts to become transparent, and CO is almost completely photo-dissociated. For masses larger than that the lines are an excellent independent tracer of disk outer radius and can break the outer radius degeneracy in the [Oi] 63.2 ?m/[C ii]157.7 ?m line ratio. Conclusions: The far-IR fine-structure lines of [Cii] and [Oi] observable with Herschel provide a promising tool to measure the disk gas mass, although they are mainly generated in the atomic surface layers. In spatially unresolved observations, none of these lines carry much information about the inner, possibly hot regions <30 AU.

Kamp, I.; Tilling, I.; Woitke, P.; Thi, W.-F.; Hogerheijde, M.

2010-01-01

149

Initial chemical and biological characterization of hydrotreated solvent refined coal (SRC-II) liquids: a status report  

SciTech Connect

This report presents the results of both chemical and biomedical research performed on a solvent refined coal (SRC-II) research material (distillate blend) which was produced by the pilot plant facility at Fort Lewis, Washington. Samples of this distillate blend were subjected to research-scale hydrotreatment by Universal Oil Products, Inc., prior to chemical and biological analysis at PNL. The samples are considered to be, in general, generically representative of raw or hydrotreated materials which might be produced by demonstration or commercial-scale facilities. The above described feedstock and hydrotreated materials were analyzed for chemical composition both prior to and after chemical fractionation. The fractionation procedure used was an acid-base-neutral solvent extraction. The fractions produced, as well as the unfractionated materials, were subjected to microbial mutagenesis testing (Ames assay) and to further chemical analysis. The principal components of the unmodified distillate blend are two and three ringed aromatic and heteroatomic species together with high concentrations of phenolic and polynuclear aromatic components relative to typical levels found in petroleum crudes. The Ames assay mutagenic response for the unfractionated material, as well as the fractions produced by the solvent separation, was reduced considerably in the hydrotreated materials compared to that of the feedstock. Total mutagenic response for the hydrotreated products was approximately 1% of that in the untreated feedstock. The concentrations of two important genetically active compound classes, the polynuclear aromatic hydrocarbons and the primary aromatic amines, were considerably reduced in both of the hydrotreated products compared to the feedstock.

Weimer, W.C.; Wilson, B.W.; Pelroy, R.A.; Craun, J.C.

1980-07-01

150

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

2012-07-04

151

Reciprocal changes in renal ACE/ANG II and ACE2/ANG 1-7 are associated with enhanced collecting duct renin in Goldblatt hypertensive rats.  

PubMed

Alterations in the balance between ANG II/ACE and ANG 1-7/ACE2 in ANG II-dependent hypertension could reduce the generation of ANG 1-7 and contribute further to increased intrarenal ANG II. Upregulation of collecting duct (CD) renin may lead to increased ANG II formation during ANG II-dependent hypertension, thus contributing to this imbalance. We measured ANG I, ANG II, and ANG 1-7 contents, angiotensin-converting enzyme (ACE) and ACE2 gene expression, and renin activity in the renal cortex and medulla in the clipped kidneys (CK) and nonclipped kidneys (NCK) of 2K1C rats. After 3 wk of unilateral renal clipping, systolic blood pressure and plasma renin activity increased in 2K1C rats (n = 11) compared with sham rats (n = 9). Renal medullary angiotensin peptide levels were increased in 2K1C rats [ANG I: (CK = 171 ± 4; NCK = 251 ± 8 vs. sham = 55 ± 3 pg/g protein; P < 0.05); ANG II: (CK = 558 ± 79; NCK = 328 ± 18 vs. sham = 94 ± 7 pg/g protein; P < 0.001)]; and ANG 1-7 levels decreased (CK = 18 ± 2; NCK = 19 ± 2 pg/g vs. sham = 63 ± 10 pg/g; P < 0.001). In renal medullas of both kidneys of 2K1C rats, ACE mRNA levels and activity increased but ACE2 decreased. In further studies, we compared renal ACE and ACE2 mRNA levels and their activities from chronic ANG II-infused (n = 6) and sham-operated rats (n = 5). Although the ACE mRNA levels did not differ between ANG II rats and sham rats, the ANG II rats exhibited greater ACE activity and reduced ACE2 mRNA levels and activity. Renal medullary renin activity was similar in the CK and NCK of 2K1C rats but higher compared with sham. Thus, the differential regulation of ACE and ACE2 along with the upregulation of CD renin in both the CK and NCK in 2K1C hypertensive rats indicates that they are independent of perfusion pressure and contribute to the altered content of intrarenal ANG II and ANG 1-7. PMID:21209009

Prieto, Minolfa C; González-Villalobos, Romer A; Botros, Fady T; Martin, Victoria L; Pagán, Javier; Satou, Ryousuke; Lara, Lucienne S; Feng, Yumei; Fernandes, Fernanda B; Kobori, Hiroyuki; Casarini, Dulce E; Navar, L Gabriel

2011-01-05

152

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

153

Chemical evolution of peroxidase — amino acid pentacyanoferrate (II) complexes as model  

NASA Astrophysics Data System (ADS)

Complexes of the type [Fe(II)(CN)5(L)] n- (wheren=3, or 4;L = glycine, histidine, imidazole, and triglycine) are proposed as evolutionary model of peroxidases. Detailed kinetic investigation for disproportionation of hydrogen peroxide catalysed by [Fe(II)(CN)5(L)] n- complexes at 40°C and pH 9.18 are discussed. Decomposition of hydrogen peroxide catalysed by above complexes conforms to Michaelis-Menten type kinetics.

Kamaluddin; Nath, Mala; Deopujari, Sushama W.

1988-09-01

154

Handbook of environmental fate and exposure data for organic chemicals. Volume II: Solvents  

Microsoft Academic Search

This book outlines in detail how individual solvents are released, transported, and degraded in the environment and how they are exposed to humans and environmental organisms. The chemicals are listed in alphabetical order by the name considered to be the most easily recognized. For each chemical, the physical properties as well as the environmental fate and monitoring data were identified

P. H. Howard; G. W. Sage; W. F. Jarvis; D. A. Gray

1990-01-01

155

Salmonella mutagenicity tests. II. Results from the testing of 270 chemicals  

Microsoft Academic Search

This publication includes data of Salmonella mutagenicity results on 270 coded chemicals, encompassing 329 tests performed by three laboratories under contract to the National Toxicology Program (NTP). The preincubation modification of the Salmonella\\/mammalian microsome assay was used to test chemicals in up to five Salmonella strains in the presence and absence of rat and hamster liver S-9. With a few

Kristien Mortelmans; Steve Haworth; Timothy Lawlor; William Speck; Beth Tainer; Errol Zeiger

1986-01-01

156

CHEMICALLY BONDED CEMENTS FROM BOILER ASH AND SLUDGE WASTES. PHASE II REPORT, SEPT.1998-JULY 1999.  

SciTech Connect

Based upon the previous Phase I research program aimed at looking for ways of recycling the KeySpan-generated wastes, such as waste water treatment sludge (WWTS) and bottom ash (BA), into the potentially useful cementitious materials called chemically bonded cement (CBC) materials, the emphasis of this Phase II program done at Brookhaven National Laboratory, in a period of September 1998 through July 1999, was directed towards the two major subjects: One was to assess the technical feasibility of WWTS-based CBC material for use as Pb-exchange adsorbent (PEA) which remediates Pb-contaminated soils in the field; and the other was related to the establishment of the optimum-packaging storage system of dry BA-based CBC components that make it a promising matrix material for the steam-cured concrete products containing sand and coarse aggregate. To achieve the goal of the first subject, a small-scale field demonstration test was carried out. Using the PEA material consisting of 30 wt% WWTS, 13 wt% Type I cement and 57 wt% water, the PES slurry was prepared using a rotary shear concrete mixer, and then poured on the Pb-contaminated soil. The PEA-to-soil ratio by weight was a factor of 2.0. The placed PEA slurry was blended with soil using hand mixing tools such as claws and shovels. The wettability of soils with the PEA was very good, thereby facilitating the soil-PEA mix procedures. A very promising result was obtained from this field test; in fact, the mount of Pb leached out from the 25-day-aged PEA-treated soil specimen was only 0.74 mg/l, meeting the requirement for EPA safe regulation of < 5 mg/l. In contrast, a large amount (26.4 mg/l) of Pb was detected from the untreated soil of the same age. Thus, this finding demonstrated that the WWTS-based CBC has a potential for use as PEA material. Regarding the second subject, the dry-packed storage system consisting of 68.7 wt% BA, 13.0 wt% calcium aluminate cement (CAC), 13.0 wt% Type I portland cement and 5.3 wt% sodium polyphosphate (NaP), was designed in response to the identification of the most effective CBC formulation in strengthening the steam-cured concrete specimens. Using this storage system with the material cost of 6.32 cents/lb, the 80 C-20 hour-steam-cured concrete specimens displayed the compressive strength of 3980 psi, tensile splitting of 416 psi, flexural strength of 808 psi, and modulus of elasticity of 3.16 x 10{sup 6} psi. Furthermore, the specimens had a good resistance to acid erosion and a lower permeability of water, compared with those of the conventional Type I cement concrete specimens. Consequently, the cost-effective BA-based CBC gave the promise of being a potentially useful material for fabricating high-performance precast concrete products, such as building blocks, pipes, and slabs.

SUGAMA,T.YAGER,K.A.BLANKENHORN,D. (KEYSPAN R AND D INITIATIVE)

1999-08-01

157

Characterizing Materials Sources and Sinks; Current Approaches: Part II. Chemical and Physical Characterization  

EPA Science Inventory

The paper discusses methods for characterizing chemical emissions from material sources, including laboratory, dynamic chamber, and full-scale studies. Indoor sources and their interaction with sinks play a major role in determining indoor air quality (IAQ). Techniques for evalua...

158

Salmonella mutagenicity tests. II. Results from the testing of 270 chemicals  

SciTech Connect

This publication includes data of Salmonella mutagenicity results on 270 coded chemicals, encompassing 329 tests performed by three laboratories under contract to the National Toxicology Program (NTP). The preincubation modification of the Salmonella/mammalian microsome assay was used to test chemicals in up to five Salmonella strains in the presence and absence of rat and hamster liver S-9. With a few exceptions, inter- and intralaboratory reproducibility was good.

Mortelmans, K.; Haworth, S.; Lawlor, T.; Speck, W.; Tainer, B.; Zeiger, E.

1986-01-01

159

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

Microsoft Academic Search

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

S. Dambrine; M. Moreau

1981-01-01

160

Chemical fibres: Present and future. Look at the next century. Part II  

Microsoft Academic Search

The trends in the development of chemical fibre production processes are analyzed and the general characteristics of the change\\u000a in their manufacture as a function of the fundamental determining factors are found. The characteristics of chemical fibre\\u000a production processes and subsequent treatments are examined and the possibilities of optimizing and intensifying existing\\u000a technologies and improving the properties of the fibres

K. E. Perepelkin

2000-01-01

161

CHEMICAL COMPOSITION OF OIL SHALE II. DEPENDENCE ON THE EXTRACTION PROCESS  

Microsoft Academic Search

Eastern and Western U.S. and Australian oil shales were retorted in a fixed-bed, bench-scale retorter, using nitrogen and carbon dioxide as sweep gases. The resulting shale oils were chemically characterized by GC\\/MS techniques. Shale oils extracted by nitrogen and carbon dioxide retorting processes were found to have different chemical compositions, even when applied to the same oil shale samples. The

Sunggyu Lee; Mark E. Polasky; Kathy L. Fullerton

1991-01-01

162

Collection of chemical-specific toxicological and pharmacokinetic data to improve risk assessments based on epidemiology: Example of Mn  

EPA Science Inventory

Data limitations led to the application of default uncertainty factors in prior risk assessments for Mn. These limitations were instrumental in the EPA generation of an alternative tier II test rule under section 211 (b) of the Clean Air Act, (fuels and fuel additives) regarding ...

163

Resonance line of B II in IUE spectra of chemically peculiar stars  

SciTech Connect

High-dispersion IUE spectroscopic observations of the B II resonance line at 1362.46 A are presented for six HgMn stars (kappa Cnc, ..mu.. Lep, 46 Draiola, CrB, HR 4072, and chi Lup), two magnetic peculiar stars (..cap alpha../sup 2/ CVn and HD 32633), and one normal B9.5 V star (..nu.. Cap). The B II line is present in great strength in kappa Cnc. It is absent from the five other HgMn stars. It is probably present, though unresolved and weak, in the magnetic stars. Its strength in ..nu.. Cap is consistent with a normal boron abundance.

Leckrone, D.S.

1981-11-15

164

A simple in situ visual and tristimulus colorimetric method for the determination of trace arsenic in environmental water after its collection on a mercury(II)-impregnated paper.  

PubMed

A simple in situ visual and tristimulus colorimetric method for the determination of trace arsenic in environmental water after collecting arsenic on a test paper impregnated with mercury(II) bromide and rosaniline chloride by its reduction aeration has been developed. The color development on the test paper is based on the formations of AsH(HgBr)2 (yellow) and/or As(HgBr)3 (brownish yellow) by a reaction between mercury(II) bromide and arsine (AsH3), which is produced through the reduction of As(III) (arsenite ion) and/or As(V) (arsenate ion) in a sample solution. To a sample solution, potassium iodide, tin(II) chloride, zinc sand and 4 ml of 6 M hydrochloric acid solution were added successively. The liberated arsine was collected on the test paper. The yellow or brownish-yellow color intensity on the test paper was measured by a tristimulus colorimeter and also by a visual method. The established method is applicable to the determination of arsenic in environmental water sample such as river, brackish, and seawater types. PMID:14753277

Rahman, Md Mustafizur; Fujinaga, Kaoru; Seike, Yasushi; Okumura, Minoru

2004-01-01

165

Topoisomerase II inhibitors, irrespective of their chemical composition, ameliorate experimental arthritis  

Microsoft Academic Search

Objective. Rheumatoid arthritis (RA) is an autoimmune disease, characterized by a chronic inflammation in the joints. The model of collagen-induced arthritis (CIA) has been extensively used to elucidate the pathogenic mechanisms relevant to human RA and is widely employed for the evaluation of potential anti-rheumatic agents. Etoposide and mitoxantrone are immuno- suppressive drugs, both acting by inhibiting the topoisomerase II

M. Verdrengh; O. Isaksson; A. Tarkowski

2004-01-01

166

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 ...

167

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 ...

168

Chemical Remediation of Nickel(II) Waste: A Laboratory Experiment for General Chemistry Students  

ERIC Educational Resources Information Center

|This project involved developing a method to remediate large quantities of aqueous waste from a general chemistry laboratory experiment. Aqueous Ni(II) waste from a general chemistry laboratory experiment was converted into solid nickel hydroxide hydrate with a substantial decrease in waste volume. The remediation method was developed for a…

Corcoran, K. Blake; Rood, Brian E.; Trogden, Bridget G.

2011-01-01

169

?????????? ??? ?????? ?????????? ????????????: ????????? II ??????? ??????? ?? ????  

Microsoft Academic Search

The article discusses the image of Catherine II in the context of the French anti-monarchist pamphlets that abounded after the French revolution and were often directed at the Russian empress as well, representing her as the “Semiramis of the North”. A special case is Marquis de Sade?s Histoire de Juliette, ou les Prospérités du vice, which unmistakably refers to Catherine

Alexandre Stroev

2011-01-01

170

Availability of epidemiologic data on humans exposed to animal carcinogens. II. Chemical uses and production volume  

SciTech Connect

We report further findings of a survey of manufacturers, processors, and importers of chemicals determined by the International Agency for Research on Cancer (IARC) to be animal carcinogens, but whose carcinogenicity in humans was considered uncertain because of inadequate epidemiologic data. We requested epidemiologic studies from the companies marketing or using any of the 75 IARC animal carcinogens in commerce in the United States. Eighteen of the 75 IARC animal carcinogens had volumes listed of 10(6) lb/year or greater, with 8 of the 13 chemicals for which studies had been completed or are in progress in this ''high volume'' category. The use category with the largest number of chemicals was drugs--19 of the 75 IARC animal carcinogens were in this category. However, none of the 13 chemicals included in epidemiologic studies was a drug. Seven of the 13 chemicals included in studies were used primarily as pesticides. We received little information on dyes and dye intermediates, experimental carcinogens, and drugs, all of which are produced in relatively low volumes; these categories represent 42 of the 75 IARC animal carcinogens. Low volumes and declining usage/production appear to be barriers to performance of epidemiologic studies. Information we received suggests that sometimes the problem of low production volume may be avoided by studying users rather than production workers. Overall, however, we expect few additional epidemiologic studies of the 75 IARC animal carcinogens.

Karstadt, M.; Bobal, R.

1982-01-01

171

Low-oxygen and chemical kinetic constraints on the geochemical niche of neutrophilic iron(II) oxidizing microorganisms  

NASA Astrophysics Data System (ADS)

Neutrophilic iron oxidizing bacteria (FeOB) must actively compete with rapid abiotic processes governing Fe(II) oxidation and as a result have adapted to primarily inhabit low-O 2 environments where they can more successfully compete with abiotic Fe(II) oxidation. The spatial distribution of these microorganisms can be observed through the chemical gradients they affect, as measured using in situ voltammetric analysis for dissolved Fe(II), Fe(III), O 2, and FeS (aq). Field and laboratory determination of the chemical environments inhabited by the FeOB were coupled with detailed kinetic competition studies for abiotic and biotic oxidation processes using a pure culture of FeOB to quantify the geochemical niche these organisms inhabit. In gradient culture tubes, the maximum oxygen levels, which were associated with growth bands of Sideroxydans lithotrophicus (ES-1, a novel FeOB), were 15-50 ?M. Kinetic measurements made on S. lithotrophicus compared biotic/abiotic (killed control) Fe oxidation rates. The biotic rate can be a significant and measurable fraction of the total Fe oxidation rate below O 2 concentrations of approximately 50 ?M, but biotic Fe(II) oxidation (via the biotic/abiotic rate comparison) becomes difficult to detect at higher O 2 levels. These results are further supported by observations of conditions supporting FeOB communities in field settings. Variablity in cell densities and cellular activity as well as variations in hydrous ferrous oxide mineral quantities significantly affect the laboratory kinetic rates. The microbial habitat (or geochemical niche) where FeOB are active is thus largely controlled by the competition between abiotic and biotic kinetics, which are dependent on Fe(II) concentration, P O2, temperature and pH in addition to the surface area of hydrous ferric oxide minerals and the cell density/activity of FeOB. Additional field and lab culture observations suggest a potentially important role for the iron-sulfide aqueous molecular cluster, FeS (aq), in the overall cycling of iron associated with the environments these microorganisms inhabit.

Druschel, Gregory K.; Emerson, David; Sutka, R.; Suchecki, P.; Luther, George W., III

2008-07-01

172

NEW YORK CITY BUS TERMINAL DIESEL EMISSIONS STUDY: MEASUREMENT AND COLLECTION OF DIESEL EXHAUST FOR CHEMICAL CHARACTERIZATION AND MUTAGENIC ACTIVITY  

EPA Science Inventory

The paper is concerned with the impact of diesel emissions on the quality of the ambient air and the resulting effects on human health. The study was designed to chemically characterize and bioassay heavy-duty diesel engine exhaust as it exists in the ambient atmosphere. Diesel e...

173

Sequestration of toxic Pb(II) ions by chemically treated rubber (Hevea brasiliensis) leaf powder.  

PubMed

Rubber leaf powder (an agricultural waste) was treated with potassium permanganate followed by sodium carbonate and its performance in the removal of Pb(II) ions from aqueous solution was evaluated. The interactions between Pb(II) ions and functional groups on the adsorbent surface were confirmed by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) coupled with X-ray energy dispersive spectroscopy (EDX). The effects of several important parameters which can affect adsorption capacity such as pH, adsorbent dosage, initial lead concentration and contact time were studied. The optimum pH range for lead adsorption was 4-5. Even at very low adsorbent dosage of 0.02 g, almost 100% of Pb(II) ions (23 mg/L) could be removed. The adsorption capacity was also dependent on lead concentration and contact time, and relatively a short period of time (60-90 min) was required to reach equilibrium. The equilibrium data were analyzed with Langmuir, Freundlich and Dubinin-Radushkevich isotherms. Based on Langmuir model, the maximum adsorption capacity of lead was 95.3 mg/g. Three kinetic models including pseudo first-order, pseudo second-order and Boyd were used to analyze the lead adsorption process, and the results showed that the pseudo second-order fitted well with correlation coefficients greater than 0.99. PMID:20397414

Kamal, Megat Hanafiah Megat Ahmad; Azira, Wan Mat Khalir Wan Khaima; Kasmawati, Mohamed; Haslizaidi, Zakaria; Saime, Wan Ngah Wan

2010-01-01

174

Multiple Equilibria in Complex Chemical Reaction Networks: II. The Species-Reaction Graph  

Microsoft Academic Search

For mass action kinetics, the capacity for multiple equilibria in an isothermal homo- geneous continuous ?ow stirred tank reactor is determined by the structure of the underlying network of chemical reactions. We suggest a new graph-theoretical method for discriminating between com- plex reaction networks that can admit multiple equilibria and those that cannot. In particular, we associate with each network

Gheorghe Craciun; Martin Feinberg

2006-01-01

175

Chemical aversion treatment of alcohol dependence. II. Future research directions for the '90s.  

PubMed

Chemical aversion treatment is one of the most promising modalities currently available for treatment of alcohol dependence. This review highlights potentially fruitful areas for future investigational efforts and poses a number of specific empirical questions. Investigation of issues delineated in this report would advance understanding of pharmacological aversion therapy vis-à-vis utility and mechanisms of action. PMID:2094680

Howard, M O; Jenson, J M

1990-12-01

176

EFFECTS OF CHEMICAL IMPURITIES ON GAS SORPTION IN POLYMERIC MEMBRANES. II. PC1 AND PC2  

Microsoft Academic Search

In recent years, polymeric membranes have been increasingly used in key unit operations such as gas separations. In theory, the performance of a polymeric membrane module depends solely on the chemical structure of the polymer and the feed gas composition. It has, however, been observed that impurities in the feed stream (such as vapors from compressor oils) affect the productivity

Bryan Pereira; Wudneh Admassu; John Jensvold

2001-01-01

177

Variation of the Si II features in the chemically peculiar star - HD 115735  

Microsoft Academic Search

The chemically peculiar star HD 115735 (= HR 5023 = 21 CVn) was observed with the 2.34 meter Vainu Bappu Telescope at Kavalur during the period of January 1999 to April 2000. A total of 47 spectrograms were obtained in the wavelength region of 3900 º to 4400 º at a resolution of 0.65 per pixel. The equivalent widths of

S. M. Sriraghavan; K. Jayakumar; G. S. D. Babu; S. Sajutha

2004-01-01

178

Development of a benchtop baking method for chemically leavened crackers. II. Validation of the method  

Technology Transfer Automated Retrieval System (TEKTRAN)

A benchtop baking method has been developed to predict the contribution of gluten functionality to overall flour performance for chemically leavened crackers. Using a diagnostic formula and procedure, dough rheology was analyzed to evaluate the extent of gluten development during mixing and machinin...

179

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

180

PRELIMINARY ASSESSMENTS OF IN VITRO PHARMACOKINETIC DATA AND EXPOSURE INFORMATION FOR THE TOXCAST PHASE II CHEMICALS  

EPA Science Inventory

Momentum has been growing in Toxicology to assess the utility of high-throughput screening (HTS) assays in the determination of chemical testing priorities. However, in vitro potencies determined in these assays do not consider in vivo bioavailability, clearance or exposure estim...

181

KIVA-II Computer Program for Transient Multidimensional Chemically Reactive Flows with Sprays.  

National Technical Information Service (NTIS)

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...

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

1987-01-01

182

THE CHEMICAL INDUSTRY-A NUCLEAR FUTURE? PART II. REACTOR PHYSICS  

Microsoft Academic Search

A review of progress and applications of nuclear reactors in the ; chemical industry is given. A discussion of reactor statistics including design ; of cores, moderators, reflectors, and shielding is presented. In addition a ; suggested reference list in this field is included. (J.R.D.);

W. R. Tomlinson; W. R. Jr

1959-01-01

183

STUDY OF CHEMICAL EQUILIBRIA IN METHANOL SYNTHESIS II. Calculation of Equilibrium Constant Kp  

Microsoft Academic Search

Based on the experimental data of Kp measured In this paper, the thermodynamic calculation of Kp from Kr and equation of state was studied and it was found that the chemical equilibrium of methanol synthesis can be described well by using Cheredeichenko (1968)'s Kr, 00 and Blssett (1977)' s Kr. rs relationship and a modified SRK equation.Meanwhile, the equilibrium constant

Liu Hui; Luo Zanchun; Zhu Bingchen

1994-01-01

184

RELATIVE DATA OF CHEMICAL EQUILIBRIA GOVERNING THE SEPARATION OF ZIRCONIUM FROM HAFNIUM. PARTS II AND III  

Microsoft Academic Search

The chemical equilibria governing the separation of zirconium from ; hafnium are considered with particular reference to the solvent. The conditions ; of separation of a mixture of tributylphosphate, diluent, and zirconium were ; studied as well as the interacUon of tributylphosphate and zirconium. The latter ; results in the formation of dibutylphosphate which has a strong complexing ; capacity

J. Hure; M. Rastoix; R. Saint-James

1961-01-01

185

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

186

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

187

Results of toxicity tests and chemical analyses conducted on sediments collected from the TNX Outfall Delta Operable Unit, July 1999  

SciTech Connect

In order to provide unit specific toxicity data that will be used to address critical uncertainty in the ecological risk assessment (ERA) for the TNX Outfall Delta Operable Unit (TNXOD OU), sediments were collected from eight locations in the Inner Swamp portion of the operable unit and two unit specific background locations. These samples were analyzed for total mercury, total uranium, and sediment toxicity.

Specht, W.L.

2000-02-11

188

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

189

The Characteristics of Chemical Constituents of Rain Water Collected by the Sequential Constant Volumetric Sampling Method in an Urban Area  

Microsoft Academic Search

In order to unveil the chemical characteristics of rain water from 1 to 8 mm, rain water measurements were conducted in downtown Okayama for one year from March, 2004 to March 2005. Analytical parameters were pH, EC and the ion concentrations, F-, Cl-, NO2-, NO3-, SO42-, PO43-, Na+, NH4+, K+, Mg2+ and Ca2+. The mean pH and EC values of

Ken Kobayashi; Eiji Yamashita; Takatoshi Hiraki; Hiroshi Ishida

2008-01-01

190

Chemical composition of precipitation and watershed samples collected at Deep Creek Lake, Garrett County, Maryland. Final report  

Microsoft Academic Search

The objective of the four-year study was to determine if acid deposition and acid stream drainage pose a significant threat to Deep Creek Lake, Maryland. The chemical composition of rain in the fourth year did not vary significantly from previous years. The annual volume-weighted mean pH of rain at the site is 3.9 - 4.0. Concentrations of hydrogen and sulfate

1985-01-01

191

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

192

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

193

Sonochemistry II.—Effects of ultrasounds on homogeneous chemical reactions and in environmental detoxification  

Microsoft Academic Search

Sonication of aqueous solutions causes cavitation in the liquid which results in the formation of H· and ·OH radical species\\u000a that can be used to reduce or oxidize certain chemical compounds. This article focuses on the effect of ultrasounds in homogeneous\\u000a reactions to examine the type of chemistry that ensues. It also deals with a rather novel method of using

Pina Colarusso; Nick Serpone

1996-01-01

194

Insights on Ceramics as Dental Materials. Part II: Chemical Surface Treatments  

Microsoft Academic Search

The purpose of surface treatment (conditioning) methods on dental ceramics is to improve the retention and bonding between\\u000a the enamel or the dentin and ceramic veneer, with the help of resin composite luting cements. These types of surface treatments\\u000a include chemically altering the surface of ceramics with some specific acidic etchants followed by applying a silane coupling\\u000a agent (silane). The

Gary Willie Ho; Jukka Pekka Matinlinna

2011-01-01

195

Chemical estimation of nitrogen mineralization in paddy rice soils: II. Comparison to greenhouse availability indices  

Microsoft Academic Search

A simple nitrogen (N) availability index is needed to improve fertilizer recommendations and, thus, reduce the opportunity for over? or under?fertilization of rice (Oryza sativa L.). Consequently, a study was conducted to develop a chemical extraction procedure that will estimate the potentially mineralizable N made available to rice during the growing season. The ammonium?nitrogen (NH4+?N) extracted with 0.05M KMnO4 (potassium

C. E. Wilson Jr; R. J. Norman; B. R. Wells; M. D. Correll

1994-01-01

196

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

197

Copper(II) complexes with sulfonamides derived from 2-picolylamine and their use as chemical nucleases  

Microsoft Academic Search

Reaction between 2-picolylamine (2-aminomethylpyridine) with 2-mesitylenesulfonyl and 4-tert-butylbenzene sulfonyl chlorides leads to the formation of 2,4,6-trimethyl-N-[pyridin-2-ilmethyl]benzenesulfonamide (Hpmesa) and 4-ter-butyl-N-[pyridin-2-ilmethyl]benzenesulfonamide (Hptbsa). These compounds react with Cu(II) salts to yield coordination compounds with CuL2 stoichiometry. The immediate environment of the metal ion is a highly distorted tetrahedron, the sulfonamide ligands acting in a bidentate fashion. Compound Hpmesa crystallizes in monoclinic space group

Benigno Macías; María V. Villa; Mónica Salgado; Joaquín Borrás; Marta González-Álvarez; Francisca Sanz

2006-01-01

198

The physico-chemical and bacteriological quality of rainwater collected over different roofing materials in Ile-Ife, southwestern Nigeria  

Microsoft Academic Search

Samples of bulk free-fall and roof-intercepted rainwater over five different roof types (iron–zinc corrugated sheets, concrete slate tiles, Adex\\/asbestos cement sheets, aluminium sheets, and thatch) were collected and analysed using standard methods with adequate quality-control and quality-assurance measures. The mean values of some of the investigated parameters for the roof-intercepted samples occurred within four continuous sets of ranges, viz:<0.11 mg l (NH),

I. F. Adeniyi; I. O. Olabanji

2005-01-01

199

Adsorption of Cu(II), Cd(II), and Pb(II) from aqueous single metal solutions by cellulose and mercerized cellulose chemically modified with succinic anhydride.  

PubMed

This work describes the preparation of new chelating material from mercerized cellulose. The first part treats the chemical modification of non-mercerized cellulose (cell 1) and mercerized cellulose (cell 2) with succinic anhydride. Mass percent gains (mpg) and degree of succinylation (DS) of cell 3 (from cell 1) and cell 4 (from cell 2) were calculated. Cell 4 in relation to cell 3 exhibited an increase in mpg and in the concentration of carboxylic functions of 68.9% and 2.8 mmol/g, respectively. Cells 5 and 6 were obtained by treatment of cells 3 and 4 with bicarbonate solution to release the carboxylate functions and characterized by FTIR. The second part compares the adsorption capacity of cells 5 and 6 for Cu2+, Cd2+, and Pb2+ ions in an aqueous single metal solution. Adsorption isotherms were developed using Langmuir model. Cell 6 in relation to cell 5 exhibited an increase in Qmax for Cu2+ (30.4 mg/g), Cd2+ (86.0 mg/g) and Pb2+ (205.9 mg/g). PMID:17706418

Gurgel, Leandro Vinícius Alves; Júnior, Osvaldo Karnitz; Gil, Rossimiriam Pereira de Freitas; Gil, Laurent Frédéric

2007-08-13

200

A Pre-Protostellar Core in L1551. II. State of Dynamical and Chemical Evolution  

NASA Astrophysics Data System (ADS)

Both analytic and numerical radiative transfer models applied to high spectral resolution CS and N2H+ data give insight into the evolutionary state of L1551 MC. This recently discovered pre-protostellar core in L1551 appears to be in the early stages of dynamical evolution. Line-of-sight infall velocities of >~0.1 km s-1 are needed in the outer regions of L1551 MC to adequately fit the data. This translates to an accretion rate of ~10-6 Msolar yr-1, uncertain to within a factor of 5 owing to unknown geometry. The observed dynamics are not due to spherically symmetric gravitational collapse and are not consistent with the standard model of low-mass star formation. The widespread, fairly uniform CS line asymmetries are more consistent with planar infall. There is modest evidence for chemical depletion in the radial profiles of CS and C18O, suggesting that L1551 MC is also chemically young. The models are not very sensitive to chemical evolution. L1551 MC lies within a quiescent region of L1551 and is evidence for continued star formation in this evolved cloud.

Swift, Jonathan J.; Welch, William J.; Di Francesco, James; Stojimirovi?, Irena

2006-01-01

201

The role of OH in the chemical evolution of protoplanetary disks. II. Gas-rich environments  

NASA Astrophysics Data System (ADS)

Context. We present a method for including gas extinction of cosmic-ray-generated UV photons in chemical models of the midplane of protoplanetary disks, focusing on its implications on ice formation and chemical evolution. Aims: Our goal is to improve on chemical models by treating cosmic rays, the main source of ionization in the midplane of the disk, in a way that is consistent with current knowledge of the gas and grain environment present in those regions. We trace the effects of cosmic rays by identifying the main chemical reaction channels and also the main contributors to the gas opacity to cosmic-ray-induced UV photons. This information is crucial in implementing gas opacities for cosmic-ray-induced reactions in full 2D protoplanetary disk models. Methods: We considered time-dependent chemical models within the range 1-10 AU in the midplane of a T Tauri disk. The extinction of cosmic-ray-induced UV photons by gaseous species was included in the calculation of photorates at each timestep. We integrated the ionization and dissociation cross sections of all atoms/molecules over the cosmic-ray-induced UV emission spectrum of H2. By analyzing the relative contribution of each gas phase species over time, we were able to identify the main contributors to the gas opacity in the midplane of protoplanetary disks. Results: At 1 AU the gas opacity contributes up to 28.2% of the total opacity, including the dust contribution. At 3-5 AU the gas contribution is 14.5% of the total opacity, and at 7-8 AU it reaches a value of 12.2%. As expected, at 10-15 AU freeze-out of species causes the gas contribution to the total opacity to be very low (6%). The main contributors to the gas opacity are CO, CO2, S, SiO, and O2. OH also contributes to the gas opacity, but only at 10-15 AU.

Chaparro Molano, G.; Kamp, I.

2012-11-01

202

Chemical evolution of dehydrogenases: Amino acid pentacyanoferrate (II) as possible intermediates  

NASA Astrophysics Data System (ADS)

Dehydrogenation of ascorbic acid and reduced nicotinamide adenine dinucleotide (NADH) with methylene blue using complexes of the type [Fe(II)(CN)5 (L)] n- (wheren=3 or 4; L=glycine, histidine, imidazole, and triglycine) as catalyst have been studied at pH 9.18. Similar kinetic behavior was observed for the dehydrogenation of ascorbic acid as well as for NADH; both reactions showed first order dependency on the substrates. First order dependence was observed only at lower concentrations of methylene blue; at higher concentrations of methylene blue, the reactions were independent of methylene blue. The order with respect to catalyst varied between 0.3 0.5. A tentative mechanism which conforms to the observed kinetics has been proposed. It is believed that on the primitive earth when the reducing potential of the atmosphere was not high enough, lower oxidation state iron complexes like [Fe(II)(CN)5(L)] n- might have been involved in dehydrogenase-type activity.

Kamaluddin; Nath, Mala; Deopujari, Sushama W.

1989-03-01

203

Synthesis and Physico?chemical Studies on a 15?Membered Hexaaza Macrocyclic Ligand Derived from Hydrazine and Its Complexes with Co(II), Ni(II), Cu(II), and Zn(II)  

Microsoft Academic Search

The macrocyclic ligand, 1,2,6,9,13,14?hexaaza?3,5,10,12?tetramethylcyclopentadecane?2,5,9,12?tetraene (L), has been prepared by the condensation reaction of hydrazine, formaldehyde, ethylenediamine, and 2,4?pentanedione in 2:1:1:2 molar ratio. Metal complexes of the type [MLX2] (M = Co(II), Ni(II), Cu(II), and Zn(II); X = Cl or NO3) have been synthesized by the reaction of L with the corresponding metal salts in methanol. The macrocyclic ligand (L) and its metal complexes have

Mohammad Shakir; Nishat Begum; Shama Parveen; Poonam Chingsubam; Shabana Tabassum

2004-01-01

204

Chemically Modified Silicagel with An Azo-Schiff Ligand and Its Metal Complexes with Cu(II), Co(II), Ni(II) and Mn(II): Applications as Catalysts on the Oxidation of Cyclohexane under Microwave Power  

Microsoft Academic Search

A novel 2-hydroxy-5-((2-hydroxyphenyl)diazenyl)benzaldehyde (L: HPDB) ligand was synthesized and bound to silica-gel which was activated with 3-aminopropyltriethoxysilane (APTES). Cu(II), Co(II), Ni(II) and Mn(II) complexes of silica-supported ligand (L: MDPMP) were synthesized. A buffer (pH = 12) was used for coupling reaction of diazonium electrophile to salicylaldehyde. The ligand and its complexes were characterized by using NMR, FT-MIR\\/FAR, elemental analysis, ICP-OES,

Serhan URU?; Mecit ÖZDEM?R; Gökhan CEYHAN; Mehmet TÜMER

2012-01-01

205

Chemical composition of five wild edible mushrooms collected from Southwest China and their antihyperglycemic and antioxidant activity.  

PubMed

Evaluation of the chemical composition and antihyperglycemic and antioxidant activity of five wild edible mushrooms (Clitocybe maxima, Catathelasma ventricosum, Stropharia rugoso-annulata, Craterellus cornucopioides and Laccaria amethystea) from Southwest China. The chemical composition assay includes proximate analysis (moisture, ash, crude protein, crude fat, total carbohydrates and total energy), bioactive compounds analysis (total phenolic, flavonoid, ascorbic acid, ergosterol, tocopherol), fatty acid analysis, amino acid analysis, phenolic compounds analysis and mineral analysis of these mushrooms. Furthermore, assays of ?-glucosidase inhibitory and ?-amylase inhibitory activity were used for evaluating antihyperglycemic activity of the mushrooms, and assays of reducing power, chelating effect on ferrous ions, scavenging effect on hydroxyl free radicals and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were used for evaluating antioxidant activity of the mushrooms. Based on the results, ethanolic and aqueous extract of these mushroom all showed antihyperglycemic and antioxidant potential. In particular, the aqueous extract of C. ventricosum revealed the highest ?-glucosidase inhibitory activity (EC50 value 2.74 ?g/mL), DPPH radical scavenging activity (EC50 value 2.86 mg/mL) and reducing power (EC50 value 0.96 mg/mL), while the aqueous extract of L. amethystea showed the highest ?-amylase inhibitory activity (EC50 value 4.37 ?g/mL) and metal chelating activity (EC50 value 2.13 mg/mL). PMID:22300772

Liu, Yun-Tao; Sun, Jun; Luo, Ze-Yu; Rao, Sheng-Qi; Su, Yu-Jie; Xu, Rong-Rong; Yang, Yan-Jun

2012-01-28

206

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

NASA Astrophysics Data System (ADS)

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 to the samples. After centrifugation, total mercury was determined in the supernatant. Organomercury compounds were selectively extracted from KBr solution using chloroform and the resultant solution was back extracted with 1% m/v L-cysteine. This solution was used for organic Hg determination. Inorganic Hg remaining in KBr solution was directly determined by chemical vapor generation electrothermal atomic absorption spectrometry. Mercury vapor generation from extracts was performed using 1 mol L - 1 HCl and 2.5% m/v NaBH 4 solutions and a batch chemical vapor generation system. Mercury vapor was collected on the gold gauze heated resistively at 80 °C and the atomization temperature was set at 650 °C. The selectivity of extraction was evaluated using liquid chromatography coupled to chemical vapor generation and determination by inductively coupled plasma mass spectrometry. The proposed method was applied for mercury analysis in shark, croaker and tuna fish tissues. Certified reference materials were used to check accuracy and the agreement was better than 95%. The characteristic mass was 60 pg and method limits of detection were 5, 1 and 1 ng g - 1 for organic, inorganic and total mercury, respectively. With the proposed method it was possible to analyze up to 2, 2 and 6 samples per hour for organic, inorganic and total Hg determination, respectively.

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

2009-06-01

207

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

2012-12-06

208

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

209

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

USGS Publications Warehouse

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 (fig. 1). The results presented here support a study that examines compositional variations of mineral dust deposited during the past few centuries in isolated natural traps spanning a region from the Mojave Desert of southern California to the central Colorado Plateau (Goldstein and others, in press; fig. 1). In particular, the study addresses the spatial and temporal variations in dust composition in the context of landscape geochemistry over a large area of the southwestern United States.

Goldstein, Harland L.; Reynolds, Richard L.; Reheis, Marith C.; Yount, James C.; Lamothe, Paul J.

2007-01-01

210

The resonance line of B II in IUE spectra of chemically peculiar stars  

NASA Astrophysics Data System (ADS)

A description is presented of high-dispersion spectroscopic observations of eight chemically peculiar stars including Kappa Cnc and Mu Lep, and of one normal comparison star, Nu Cap, in the vicinity of 1362 A. The reported data were obtained with the International Ultraviolet Explorer during the first 15 months of its operation. The initial reduction of the data, which were originally described in a qualitative summary by Leckrone (1980), was affected by a serious error in the calibration of the instrument's intensity transfer function. This error has been corrected in the currently presented data. The results of spectrum syntheses of the 1362 A feature are also described for several of the stars.

Leckrone, D. S.

1981-11-01

211

NMR chemical shift reagents in structural determination of lipid derivatives: II. Methyl petroselinate and methyl oleate  

Microsoft Academic Search

Whentris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octaneodionato)europium (III)—Eu(fod)3—forms a complex with a sufficiently basic functional group in a donor molecule, the change in the magnetic environment of\\u000a protons near the coordination site causes their nuclear magnetic resonance (NMR) signals to shift to different positions.\\u000a Consequently Eu(fod)3 and other compounds that similarly affect NMR signals have been designated chemical shift reagents (csr). Because of their\\u000a ability to

John P. Wineburg; Daniel Swern

1972-01-01

212

ANALYSIS OF TWO SMALL MAGELLANIC CLOUD H II REGIONS CONSIDERING THERMAL INHOMOGENEITIES: IMPLICATIONS FOR THE DETERMINATIONS OF EXTRAGALACTIC CHEMICAL ABUNDANCES  

SciTech Connect

We present long-slit spectrophotometry considering the presence of thermal inhomogeneities (t{sup 2}) of two H II regions in the Small Magellanic Cloud (SMC): NGC 456 and NGC 460. Physical conditions and chemical abundances were determined for three positions in NGC 456 and one position in NGC 460, first under the assumption of uniform temperature and then allowing for the possibility of thermal inhomogeneities. We determined t{sup 2} values based on three different methods: (1) by comparing the temperature derived using oxygen forbidden lines with the temperature derived using helium recombination lines (RLs), (2) by comparing the abundances derived from oxygen forbidden lines with those derived from oxygen RLs, and (3) by comparing the abundances derived from ultraviolet carbon forbidden lines with those derived from optical carbon RLs. The first two methods averaged t{sup 2} = 0.067 {+-} 0.013 for NGC 456 and t{sup 2} = 0.036 {+-} 0.027 for NGC 460. These values of t{sup 2} imply that when gaseous abundances are determined with collisionally excited lines they are underestimated by a factor of nearly two. From these objects and others in the literature, we find that in order to account for thermal inhomogeneities and dust depletion, the O/H ratio in low-metallicity H II regions should be corrected by 0.25-0.45 dex depending on the thermal structure of the nebula or by 0.35 dex if such information is not available.

Pena-Guerrero, Maria A.; Peimbert, Antonio; Peimbert, Manuel [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Apdo. Postal 70-264, Mexico 04510 D.F. (Mexico); Ruiz, Maria Teresa, E-mail: guerrero@astroscu.unam.mx, E-mail: antonio@astroscu.unam.mx, E-mail: peimbert@astroscu.unam.mx, E-mail: mtruiz@das.uchile.cl [Departamento de Astronomia, Universidad de Chile, Casilla Postal 36D, Santiago de Chile (Chile)

2012-02-20

213

Toxic essential oils. Part II: chemical, toxicological, pharmacological and microbiological profiles of Artemisia annua L. volatiles.  

PubMed

Botanical drugs based on Artemisia annua L. (Asteraceae) are important in the treatment of malaria. Alongside with artemisinin, this aromatic species produces high and variable amounts of other chemicals that have mostly unknown biological/pharmacological activities. Herein, we have studied the toxicological/pharmacological profile of volatile constituents of a Serbian population of A. annua. Fifty-eight components were identified, among them, artemisia ketone (35.7%), ?-pinene (16.5%) and 1,8-cineole (5.5%) were the most abundant ones. Significant variability of A. annua volatile profile was confirmed by means of agglomerative hierarchical cluster analysis indicating the existence of several different A. annua chemotypes. In an attempt to connect the chemical profile of A. annua oil with its biological/toxicological effects, we have evaluated in vivo and/or in vitro toxicity (including hepato- and nephrotoxicity/protection), antinociceptive, antioxidant (DPPH, ABTS and superoxide radical scavenging activity assays), enzyme inhibiting (protein kinase A and ?-amylase) and antimicrobial potential of A. annua oil and of its constituents. Our results revealed that the beneficial properties of A. annua botanical drugs are not limited only to their antimalarial properties. Taking into account its relatively low toxicity, the usage of A. annua volatiles (at least of the herein studied population) does not represent a health risk. PMID:23607933

Radulovi?, Niko S; Randjelovi?, Pavle J; Stojanovi?, Nikola M; Blagojevi?, Polina D; Stojanovi?-Radi?, Zorica Z; Ili?, Ivan R; Djordjevi?, Vidosava B

2013-04-20

214

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

2012-12-10

215

Chemically synthesised atomically precise gold clusters deposited and activated on titania. Part II.  

PubMed

Synchrotron XPS was used to investigate a series of chemically synthesised, atomically precise gold clusters Au(n)(PPh3)y (n = 8, 9 and 101, y depending on the cluster size) immobilized on anatase (titania) nanoparticles. Effects of post-deposition treatments were investigated by comparison of untreated samples with analogues that have been heat treated at 200 °C in O2, or in O2 followed by H2 atmosphere. XPS data shows that the phosphine ligands are oxidised upon heat treatment in O2. From the position of the Au 4f(7/2) peak it can be concluded that the clusters partially agglomerate immediately upon deposition. Heating in oxygen, and subsequently in hydrogen, leads to further agglomeration of the gold clusters. It is found that the pre-treatment plays a crucial role in the removal of ligands and agglomeration of the clusters. PMID:23907108

Anderson, David P; Adnan, Rohul H; Alvino, Jason F; Shipper, Oliver; Donoeva, Baira; Ruzicka, Jan-Yves; Al Qahtani, Hassan; Harris, Hugh H; Cowie, Bruce; Aitken, Jade B; Golovko, Vladimir B; Metha, Gregory F; Andersson, Gunther G

2013-09-21

216

Chemical behavior of radioiodine in boiling water reactor systems II; Effects of hydrogen water chemistry  

SciTech Connect

The investigation of the chemistry and steam transport behavior of radioiodine is boiling water reactors has been extended to four more reactors during full-scale hydrogen water chemistry (HWC) tests. Under the reducing coolant chemistry environment, most of the radioiodine was found in the iodide (I{sup {minus}}) form. The iodine steam carryover was found to increase in varying degree under HWC conditions in two reactors and was practically unchanged in the other two reactors. In this paper the variations in radioiodine chemical forms and steam carryover are discussed in terms of radiolytic reactions, and the effect of copper ions in the reactor water is qualitatively evaluated. The effect of HWC on radioiodine transport is not significant.

Lin, C.C. (General Electric Co., Pleasanton, CA (United States). Vallecitos Nuclear Center)

1992-01-01

217

Redox-controlled multiple-species reactive chemical transport, part II: Verification and application  

NASA Astrophysics Data System (ADS)

A redox-controlled multiple-species, multidimensional reactive chemical transport model, DYNAMIX, has been presented in part 1 of this paper. In part 2 the model is checked against two other independently developed reactive chemical transport codes. Simulated results from DYNAMIX agree reasonably well with those obtained from the other two models. Two approaches for simulating redox reactions, an external approach (based on hypothetical electron activity) and an effective internal approach (based on conservation of electrons), have been examined. The results show that in the external approach the simulated redox front is smeared out by diffusion and dispersion, whereas in the effective internal approach the redox front is sharp and is controlled by the redox reactions. The evolution of solid phases from the two approaches give markedly different mineral assemblages. It is suggested that the external approach is of relevance in industrial processes such as electrometallurgy, in which mineral dissolution is driven by externally supplied electric power. The effective internal approach is applicable to hydrogeochemical systems (groundwater contamination, diagenesis, ore formation, rock weathering, and soil genesis) in which redox potential is dictated by the states of the redox species. The results also suggest that in the presence of precipitation (and consequent retardation of the concentration front), spreading due to hydrodynamic dispersion may be significantly inhibited. To demonstrate the applicability of DYNAMIX for realistic field problems, two field cases are simulated by this model. In the first case, the supergene enrichment of copper at Butte, Montana, the simulated mineral assemblages and their distributions agree reasonably with the mineral assemblages and the ore grade observed in the field. In the second case, involving two-dimensional contaminant transport in a hypothetic aquifer, the simulated results suggest that DYNAMIX is capable of handling a realistic multi-dimensional field problem with several hundred grid blocks and time scales of practical interest.

Liu, Chen Wuing; Narasimhan, T. N.

1989-05-01

218

Chemical Processes in Protoplanetary Disks. II. On the Importance of Photochemistry and X-Ray Ionization  

NASA Astrophysics Data System (ADS)

We investigate the impact of photochemistry and X-ray ionization on the molecular composition of, and ionization fraction in, a protoplanetary disk surrounding a typical T Tauri star. We use a sophisticated physical model, which includes a robust treatment of the radiative transfer of UV and X-ray radiation, and calculate the time-dependent chemical structure using a comprehensive chemical network. In previous work, we approximated the photochemistry and X-ray ionization; here, we recalculate the photoreaction rates using the explicit UV wavelength spectrum and wavelength-dependent reaction cross sections. We recalculate the X-ray ionization rate using our explicit elemental composition and X-ray energy spectrum. We find that photochemistry has a larger influence on the molecular composition than X-ray ionization. Observable molecules sensitive to the photorates include OH, HCO+, N2H+, H2O, CO2, and CH3OH. The only molecule significantly affected by the X-ray ionization is N2H+, indicating that it is safe to adopt existing approximations of the X-ray ionization rate in typical T Tauri star-disk systems. The recalculation of the photorates increases the abundances of neutral molecules in the outer disk, highlighting the importance of taking into account the shape of the UV spectrum in protoplanetary disks. A recalculation of the photoreaction rates also affects the gas-phase chemistry due to the adjustment of the H/H2 and C+/C ratios. The disk ionization fraction is not significantly affected by the methods adopted to calculate the photochemistry and X-ray ionization. We determine that there is a probable "dead zone" where accretion is suppressed, present in a layer, Z/R <~ 0.1-0.2, in the disk midplane, within R ? 200 AU.

Walsh, Catherine; Nomura, Hideko; Millar, T. J.; Aikawa, Yuri

2012-03-01

219

Martian Surface Composition From Multiple Datasets, Part II: Chemical Analysis of Global Mineral Distributions from MGS-TES  

NASA Astrophysics Data System (ADS)

Koeppen and Hamilton [2008, JGR-Planets] produced global mineral maps of Mars from Thermal Emission Spectrometer (TES) data using a library of mineral and amorphous phase spectra and a linear least squares fitting algorithm. Here we will use known or estimated bulk chemistries of the phases in the Koeppen and Hamilton [2008] spectral library, along with each phase's modeled abundance in the TES data from that work, to calculate effective bulk chemistry for Martian dark regions at a spatial resolution of ~3x6 km. By doing this, we are able to analyze global bulk chemical variation as well as enable direct comparisons between TES data and chemical/elemental abundance maps (e.g., wt.% SiO2) produced using data collected by the Gamma Ray Spectrometer. A second chemical analysis also makes use of the Koeppen and Hamilton [2008] global mineral maps and focuses on the spatial variations in solid solution chemistry among feldspars, pyroxenes, high silica phases (e.g., silica, phyllosilicates, zeolites), and sulfates. Koeppen and Hamilton [2008] demonstrated that there is a range of Mg-Fe olivine compositions on Mars and that there are distinct geographic distributions of those phases, pointing to spatial variations in geologic processes. We use the same methodology to search for correlations between geography (e.g., geologic unit, latitude), elevation, and chemical (solid solution) composition. Preliminary analyses of pyroxene chemical variation reveal that globally, low-Ca pyroxenes are dominated by the clinopyroxene pigeonite and that among orthopyroxenes, Mg-rich phases (enstatite) are virtually never identified and phases with greater proportions of Fe (bronzite and hypersthene) are identified in distinct geographic and/or geologic terrains. Only the distribution of hypersthene (the composition of pyroxene in the Martian meteorite ALH 84001) correlates with the OMEGA-mapped distribution of low-Ca pyroxene suggesting that OMEGA-based maps of high-Ca pyroxene may include pigeonite. Many of the chemical-spatial variations observed among solid solution phases in TES data correspond to both relative surface age and the distribution of lithologic units identified by Rogers and Christensen [2007, JGR-Planets], where the lithologic units were identified using a different analytical approach, giving us confidence in the variations observed in our mineral maps. These results point to variations in and/or the evolution of igneous compositions over time. Any observable variations in other phase groups (e.g., sulfates, phyllosilicates) may indicate variations in the timing and extent of aqueous or alteration processes over time.

Hamilton, V. E.; Rogers, D.

2010-12-01

220

The Characteristics of Chemical Constituents of Rain Water Collected by the Sequential Constant Volumetric Sampling Method in an Urban Area  

NASA Astrophysics Data System (ADS)

In order to unveil the chemical characteristics of rain water from 1 to 8 mm, rain water measurements were conducted in downtown Okayama for one year from March, 2004 to March 2005. Analytical parameters were pH, EC and the ion concentrations, F-, Cl-, NO2-, NO3-, SO42-, PO43-, Na+, NH4+, K+, Mg2+ and Ca2+. The mean pH and EC values of the precipitations from 1 to 4 mm, which would be affected largely by the washout effect in the observational area, were 4.46 and 32.7?S/cm, respectively. And, the mean ion concentrations of NO3- and nss-SO42-, which were main acid rain constituents, were 1.1mg/l and 0.9 mg/l, respectively. The mean pH and EC values of the precipitations from 5 to 8 mm, which would be affected largely by the rainout effect, were 4.60 and 20.4?S/cm, respectively. The mean ion concentrations of NO3- and nss-SO42- were 1.6mg/l and 1.4mg/l, respectively. The air mass back trajectory analysis was conducted for 5 days until the day of the rain event. The analyzed trajectories were classified into 4 typical routes advected from the Eurasian Continent, the central part of the North Pacific Ocean, Southeast Asia and the East Asian coast. And, the different chemical characteristics depending on the route were recognized. In the case of the Southeast Asia route, the ion concentrations of NO3- and nss-SO42- were highest, 2.4mg/l and 2.1mg/l, respectively. Then, in the case of the Eurasian Continent route, the concentrations were 1.5mg/l and 1.5mg/l. In the case of the East Asian coast route, the concentrations were 1.3mg/l and 1.1mg/l. In the case of the central part of the Pacific Ocean route, the concentrations were lowest, 0.7mg/l and 1.1mg/l, respectively.

Kobayashi, Ken; Yamashita, Eiji; Hiraki, Takatoshi; Ishida, Hiroshi

221

Femtochemistry of orange II in solution and in chemical and biological nanocavities.  

PubMed

In this work, we report on studies of the nature of the dynamics and hydrophobic binding in cyclodextrins and human serum albumin protein complexes with orange II. With femtosecond time resolution, we examined the proton-transfer and trans-cis isomerization reactions of the ligand in these nanocavities and in pure solvents. Because of confinement at the ground state, the orientational motion in the formed phototautomer is restricted, leading to a rich dynamics. Therefore, the emission lifetimes span a large window of tens to hundreds of picoseconds in the cavities. Possible H-bond interactions between the guest and cyclodextrin do not affect the caged dynamics. For the protein-ligand complexes, slow diffusional motion ( approximately 630 ps) observed in the anisotropy decay indicates that the binding structure is not completely rigid, and the embedded guest is not frozen with the hydrophobic pocket. The ultrafast isomerization and decays are explained in terms of coupling motions between N-N and C-N stretching modes of the formed tautomer. We discuss the role of confinement on the trans-cis isomerization with the cavities and its relationships to frequency and time domains of nanostructure emission. PMID:16365300

Douhal, Abderrazzak; Sanz, Mikel; Tormo, Laura

2005-12-19

222

Chemical composition of precipitation and watershed samples collected at Deep Creek Lake, Garrett County, Maryland. Final report  

SciTech Connect

The objective of the four-year study was to determine if acid deposition and acid stream drainage pose a significant threat to Deep Creek Lake, Maryland. The chemical composition of rain in the fourth year did not vary significantly from previous years. The annual volume-weighted mean pH of rain at the site is 3.9 - 4.0. Concentrations of hydrogen and sulfate ions are higher in summer rain, particularly for storms characterized by northwesterly winds. Summertime rain produces about 60 percent of the annual sulfate and hydrogen ion deposition at the site. The average lake water pH has remained stable during the four-year study. Acid input from Cherry Creek, impacted by geological acids, was about equal to the acid deposited directly on the lake surface by rain. During most of the year neutralization of geologic acid drainage by the bottom sediments of Cherry Creek Cove is rapid. A USGS investigation of the geology in the area found extensive alkaline rock outcroppings in the basin and underlaying the lake. It appears that concerns about rapid acidification of the lake are not well founded.

Campbell, S.

1985-10-01

223

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

224

Chemicals of emerging concern in water and bottom sediment in Great Lakes areas of concern, 2010 to 2011-Collection methods, analyses methods, quality assurance, and data  

USGS Publications Warehouse

The U.S. Geological Survey (USGS) cooperated with the U.S. Environmental Protection Agency and the U.S. Fish and Wildlife Service on a study to identify the occurrence of chemicals of emerging concern (CECs) in water and bottom-sediment samples collected during 2010–11 at sites in seven areas of concern (AOCs) throughout the Great Lakes. Study sites include tributaries to the Great Lakes in AOCs located near Duluth, Minn.; Green Bay, Wis.; Roches­ter, N.Y.; Detroit, Mich.; Toledo, Ohio; Milwaukee, Wis.; and Ashtabula, Ohio. This report documents the collection meth­ods, analyses methods, quality-assurance data and analyses, and provides the data for this study. Water and bottom-sediment samples were analyzed at the USGS National Water Quality Laboratory in Denver, Colo., for a broad suite of CECs. During this study, 135 environmental and 23 field dupli­cate samples of surface water and wastewater effluent, 10 field blank water samples, and 11 field spike water samples were collected and analyzed. Sixty-one of the 69 wastewater indicator chemicals (laboratory method 4433) analyzed were detected at concentrations ranging from 0.002 to 11.2 micrograms per liter. Twenty-eight of the 48 pharmaceuticals (research method 8244) analyzed were detected at concentrations ranging from 0.0029 to 22.0 micro­grams per liter. Ten of the 20 steroid hormones and sterols analyzed (research method 4434) were detected at concentrations ranging from 0.16 to 10,000 nanograms per liter. During this study, 75 environmental, 13 field duplicate samples, and 9 field spike samples of bottom sediment were collected and analyzed for a wide variety of CECs. Forty-seven of the 57 wastewater indicator chemicals (laboratory method 5433) analyzed were detected at concentrations ranging from 0.921 to 25,800 nanograms per gram. Seventeen of the 20 steroid hormones and sterols (research method 6434) analyzed were detected at concentrations ranging from 0.006 to 8,921 nanograms per gram. Twelve of the 20 pharmaceuticals (research method 8244) analyzed were detected at concentrations ranging from 2.35 to 453.5 nanograms per gram. Six of the 11 antidepressants (research method 9008) analyzed were detected at concentrations ranging from 2.79 to 91.6 nanograms per gram.

Lee, Kathy E.; Langer, Susan K.; Menheer, Michael A.; Foreman, William T.; Furlong, Edward T.; Smith, Steven G.

2012-01-01

225

Chemical analyses of soil samples collected from the Sandia National Laboratories, Kauai Test Facility, HI, 1999-2007.  

SciTech Connect

In 1999, 2002, and 2007, the Environmental Programs and Assurance Department of Sandia National Laboratories (SNL) at the Kauai Test Facility (KTF), HI, has collected soil samples at numerous locations on-site, on the perimeter, and off-site for determining potential impacts to the environs from operations at KTF. These samples were submitted to an analytical laboratory for metal-in-soil analyses. Intercomparisons of these results were then made to determine if there was any statistical difference between on-site, perimeter, and off-site samples, or if there were increasing or decreasing trends that indicated that further investigation might be warranted. This work provided the SNL Environmental Programs and Assurance Department with a sound baseline data reference against which to compare future operational impacts. In addition, it demonstrates the commitment that the Laboratories have to go beyond mere compliance to achieve excellence in its operations. This data is presented in graphical format with narrative commentaries on particular items of interest.

Miller, Mark Laverne

2007-11-01

226

Chemical and colloidal analyses of natural seep water collected from the exploratory studies facility inside Yucca Mountain, Nevada, USA.  

PubMed

Yucca Mountain is being considered as a geological repository for the USA's spent nuclear fuel and high-level nuclear waste. Numerous groundwater seeps appeared during March 2005 within the exploratory studies facility (ESF), a tunnel excavated in the mountain. Because of the relevance to radionuclide transport and unsaturated zone-modeling studies, we analyzed the seep samples for major anions and cations, rare earth elements, and colloids. Major ion species and elemental concentrations in seep samples reflect interaction of the water with the volcanic rock and secondary calcites. Elemental fractograms from flow-injection field-flow fractionation ICP-MS scans detected Br, Ca, Cl, Cu, Fe, I, Mg, Si, Sr, W, and U at void fractions, suggesting they may be present in the form of dissolved anions. Colloids approximately 10 nm in hydrodynamic diameter, possibly calcite, were also present in the seepage samples. Geochemical calculations indicate, however, these may be an artifact (not present in the groundwater) which arose because of loss of CO2 during sample collection and storage. PMID:17505890

Cizdziel, James V; Guo, Caixia; Steinberg, Spencer M; Yu, Zhongbo; Johannesson, Karen H

2007-05-16

227

Chemical analyses of soil samples collected from the Sandia National Laboratories, New Mexico environs, 1993-2005.  

SciTech Connect

From 1993 through 2005, the Environmental Management Department of Sandia National Laboratories in Albuquerque, New Mexico (SNL/NM), has collected soil and sediment samples at numerous locations on-site, on the perimeter, and off-site for the purpose of determining potential impacts to the environs from operations at the Laboratories. These samples were submitted to an analytical laboratory for metal-in-soil analyses. Intercomparisons of these results were then made to determine if there was any statistical difference between on-site, perimeter, and off-site samples, or if there were year-to-year increasing or decreasing trends which indicated that further investigation may be warranted. This work provided the SNL Environmental Management Department with a sound baseline data reference against which to assess potential current operational impacts or to compare future operational impacts. In addition, it demonstrates the commitment that the Laboratories have to go beyond mere compliance to achieve excellence in its operations. This data is presented in graphical format with narrative commentaries on particular items of interest.

Deola, Regina Anne; Oldewage, Hans D.; Herrera, Heidi; Miller, Mark Laverne

2006-03-01

228

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

229

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

2013-01-24

230

Processes involved in salt-dome development II: thermal, gravitational, and chemical effects  

SciTech Connect

The quantitative investigation of processes involved in salt dome development include thermal, gravitational, and chemical effects of uprising salt domes. The authors find that (a) there must be a positive-temperature anomaly occurring around the upper flanks of a salt dome but that organic maturation is typically so low that the resulting enhanced maturation is still insignificant for hydrocarbon generation, (b) there must be a negative temperature anomaly occurring around the lower flanks of a salt dome that significantly inhibits overmaturation of hydrocarbons and so enlarges the hydrocarbon window, (c) the magnitude of the negative gravity anomaly associated with a salt dome, that is predicted by an equilibrium model of gravitational instability is much smaller than the observed values, implying that salt domes are inhibited in their development either by lateral sediment strength, under compaction of the overlying or surrounding sediments, or by the available supply of salt, (d) the 4 major current suggestions for cap-rock formation discussed in the literature have serious deficiencies; none of them is capable of supplying enough anhydrite for the observed thicknesses of cap rocks. Permeability enhancement by 2 orders of magnitude is required for any of these processes to be viable. A method for producing such an enhancement is based on fluid characteristics in generalized sandstone and shale section.

Lerche, I.; O'Brien, J.J.

1985-02-01

231

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

232

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

233

The Dual Origin of Stellar Halos. II. Chemical Abundances as Tracers of Formation History  

NASA Astrophysics Data System (ADS)

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 [?/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 Lsstarf galaxies.

Zolotov, Adi; Willman, Beth; Brooks, Alyson M.; Governato, Fabio; Hogg, David W.; Shen, Sijing; Wadsley, James

2010-09-01

234

Features in chemical kinetics. II. A self-emerging definition of slow manifolds  

NASA Astrophysics Data System (ADS)

In the preceding paper of this series (Part I [P. Nicolini and D. Frezzato, J. Chem. Phys. 138, 234101 (2013)]) we have unveiled some ubiquitous features encoded in the systems of polynomial differential equations normally applied in the description of homogeneous and isothermal chemical kinetics (mass-action law). Here we proceed by investigating a deeply related feature: the appearance of so-called slow manifolds (SMs) which are low-dimensional hyper-surfaces in the neighborhood of which the slow evolution of the reacting system occurs after an initial fast transient. Indeed a geometrical definition of SM, devoid of subjectivity, ``naturally'' follows in terms of a specific sub-dimensional domain embedded in the peculiar region of the concentrations phase-space that in Part I we termed as ``attractiveness region.'' Numerical inspections on simple low-dimensional model cases are presented, including the benchmark case of Davis and Skodje [J. Chem. Phys. 111, 859 (1999)] and the preliminary analysis of a simplified model mechanism of hydrogen combustion.

Nicolini, Paolo; Frezzato, Diego

2013-06-01

235

Features in chemical kinetics. II. A self-emerging definition of slow manifolds.  

PubMed

In the preceding paper of this series (Part I [P. Nicolini and D. Frezzato, J. Chem. Phys. 138, 234101 (2013)]) we have unveiled some ubiquitous features encoded in the systems of polynomial differential equations normally applied in the description of homogeneous and isothermal chemical kinetics (mass-action law). Here we proceed by investigating a deeply related feature: the appearance of so-called slow manifolds (SMs) which are low-dimensional hyper-surfaces in the neighborhood of which the slow evolution of the reacting system occurs after an initial fast transient. Indeed a geometrical definition of SM, devoid of subjectivity, "naturally" follows in terms of a specific sub-dimensional domain embedded in the peculiar region of the concentrations phase-space that in Part I we termed as "attractiveness region." Numerical inspections on simple low-dimensional model cases are presented, including the benchmark case of Davis and Skodje [J. Chem. Phys. 111, 859 (1999)] and the preliminary analysis of a simplified model mechanism of hydrogen combustion. PMID:23802946

Nicolini, Paolo; Frezzato, Diego

2013-06-21

236

Bioactivity, chemical profiling, and 16S rRNA-based phylogeny of Pseudoalteromonas strains collected on a global research cruise.  

PubMed

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 activity. Here, we profile secondary metabolites of these strains to determine if particular compounds serve as strain or species markers and to determine if the secondary metabolite profile of one strain represents the bioactivity of the entire species. 16S rRNA gene similarity divided the strains into two primary groups: One group (51 strains) consisted of bacteria which retained antibacterial activity, 48 of which were pigmented, and another group (50 strains) of bacteria which lost antibacterial activity upon sub-culturing, two of which were pigmented. The group that retained antibacterial activity consisted of six clusters in which strains were identified as Pseudoalteromonas luteoviolacea, Pseudoalteromonas aurantia, Pseudoalteromonas phenolica, Pseudoalteromonas ruthenica, Pseudoalteromonas rubra, and Pseudoalteromonas piscicida. HPLC-UV/VIS analyses identified key peaks, such as violacein in P. luteoviolacea. Some compounds, such as a novel bromoalterochromide, were detected in several species. HPLC-UV/VIS detected systematic intra-species differences for some groups, and testing several strains of a species was required to determine these differences. The majority of non-antibacterial, non-pigmented strains were identified as Pseudoalteromonas agarivorans, and HPLC-UV/VIS did not further differentiate this group. Pseudoalteromonas retaining antibacterial were more likely to originate from biotic or abiotic surfaces in contrast to planktonic strains. Hence, the pigmented, antibacterial Pseudoalteromonas have a niche specificity, and sampling from marine biofilm environments is a strategy for isolating novel marine bacteria that produce antibacterial compounds. PMID:21305330

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

2011-02-09

237

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

SciTech Connect

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. Jr.; Liber, H.L.; Thilly, W.G.

1987-08-01

238

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

239

The influence of chemical composition on the properties of Cepheid stars. II. The iron content  

NASA Astrophysics Data System (ADS)

Context: The Cepheid period-luminosity (PL) relation is unquestionably one of the most powerful tools at our disposal for determining the extragalactic distance scale. While significant progress has been made in the past few years towards its understanding and characterization both on the observational and theoretical sides, the debate on the influence that chemical composition may have on the PL relation is still unsettled. Aims: With the aim to assess the influence of the stellar iron content on the PL relation in the V and K bands, we have related the V-band and the K-band residuals from the standard PL relations of Freedman et al. (2001, ApJ, 553, 47) and Persson et al. (2004, AJ, 128, 2239), respectively, to [Fe/H]. Methods: We used direct measurements of the iron abundances of 68 Galactic and Magellanic Cepheids from FEROS and UVES high-resolution and high signal-to-noise spectra. Results: We find a mean iron abundance ([Fe/H]) about solar (? = 0.10) for our Galactic sample (32 stars), ~-0.33 dex (? = 0.13) for the Large Magellanic Cloud (LMC) sample (22 stars) and ~-0.75 dex (? = 0.08) for the Small Magellanic Cloud (SMC) sample (14 stars). Our abundance measurements of the Magellanic Cepheids double the number of stars studied up to now at high resolution. The metallicity affects the V-band Cepheid PL relation and metal-rich Cepheids appear to be systematically fainter than metal-poor ones. These findings depend neither on the adopted distance scale for Galactic Cepheids nor on the adopted LMC distance modulus. Current data do not allow us to reach a firm conclusion concerning the metallicity dependence of the K-band PL relation. The new Galactic distances indicate a small effect, whereas the old ones support a marginal effect. Conclusions: Recent robust estimates of the LMC distance and current results indicate that the Cepheid PL relation is not Universal. Based on observations made with ESO Telescopes at Paranal and La Silla Observatories under proposal ID 66.D-0571. Full Table [see full textsee full textsee full textsee full text] is only available in electronic form at http://www.aanda.org

Romaniello, M.; Primas, F.; Mottini, M.; Pedicelli, S.; Lemasle, B.; Bono, G.; François, P.; Groenewegen, M. A. T.; Laney, C. D.

2008-09-01

240

Correlations between 31P chemical shift anisotropy and molecular structure in polycrystalline O,O'-dialkyldithiophosphate zinc(II) and nickel(II) complexes: 31P CP/MAS NMR and ab initio quantum mechanical calculation studies.  

PubMed

Different potassium salts and zinc(II) and nickel(II) O,O'-dialkyldithiophosphate complexes were studied by solid-state 31P CP/MAS and static NMR and ab initio quantum mechanical calculations. Spectra were obtained at different spinning frequencies, and the intensities of the spinning sidebands were used to estimate the chemical shift anisotropy parameters. Useful correlations between the shapes of the 31P chemical shift tensor and the type of ligand were found: terminal ligands have negative values of the skew kappa, while bridging and ionic ligands have positive values for this parameter. The experimental results were compared with known X-ray diffraction structures for some of these complexes as well as with ab initio quantum mechanical calculations, and a useful correlation between the delta22 component of the 31P chemical shift tensor and the S-P-S bond angle in the O,O'-dialkyldithiophoshate zinc(II) and nickel(II) complexes was found: delta22 increases more than 50 ppm with the increase of S-P-S bond angle from ca. 100 degrees to 120 degrees , while the other two principal values of the tensor, delta11 and delta33, are almost conserved. This eventually leads to the change in sign for kappa in the bridging type of ligand, which generally has a larger S-P-S bond angle than the terminally bound O,O'-dialkyldithiophosphate group forming chelating four-membered P(ss)Me heterocycles. PMID:15713100

Larsson, Anna-Carin; Ivanov, Alexander V; Forsling, Willis; Antzutkin, Oleg N; Abraham, Anu E; de Dios, Angel C

2005-02-23

241

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

242

Correlating chemical changes in subchondral bone mineral due to aging or defective type II collagen by Raman spectroscopy  

NASA Astrophysics Data System (ADS)

We show that early indicators of osteoarthritis are observed in Raman spectroscopy by probing femur surfaces excised from mouse models of early-onset osteoarthritis. Current clinical methods to examine arthritic joints include radiological examination of the joint, but may not be capable of detecting subtle chemical changes in the bone tissue, which may provide the earliest indications of osteoarthritis. Recent research has indicated that the subchondral bone may have a more significant role in the onset of osteoarthritis than previously realized. We will report the effect of age and defective type II collagen on Raman band area ratios used to describe bone structure and function. The carbonate-to-phosphate ratio is used to assess carbonate substitution into the bone mineral and the mineral-to-matrix ratio is used to measure bone mineralization. Mineral-to-matrix ratios indicate that subchondral bone becomes less mineralized as both the wild-type and Del1 (+/-) transgenic mice age. Moreover, the mineral-to-matrix ratios show that the subchondral bone of Del1 (+/-) transgenic mice is less mineralized than that of the wild-type mice. Carbonate-to-phosphate ratios from Del1 (+/-) transgenic mice follow the same longitudinal trend as wild-type mice. The ratio is slightly higher in the transgenic mice, indicating more carbonate content in the bone mineral. Raman characterization of bone mineralization provides an invaluable insight into the process of cartilage degeneration and the relationship with subchondral bone at the ultrastructural level.

Dehring, Karen A.; Roessler, Blake J.; Morris, Michael D.

2007-03-01

243

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 (PM2.5) would be changed remains unclear. In present study we compared in vitro biological responses of PM2.5 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 20PM2.5 samples. Significant, dose-dependent effects on cell viability, cytokine/chemokine release and mRNA expressions were observed. The cytotoxicity caused at equal mass concentration of PM2.5 was notably reduced (p<0.05) by control measures, and significant association was found for viability and elemental zinc in PM2.5. Endotoxin content in PM2.5 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. PM2.5 toxicity in Beijing was substantially dependent on its chemical components, and lowering the levels of specific components in PM2.5 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

2013-08-17

244

Size-resolved Chemical Composition of Cloud and Rain Water Collected during the Puerto Rico African Dust and Clouds Study (PRADACS) Campaign  

NASA Astrophysics Data System (ADS)

The underlying physico-chemical processes of dust-aerosol interactions are poorly understood; even less understood is how aging impacts cloud properties and climate as the particles travel from Africa to the Caribbean region. Caribbean landmasses have tropical montane cloud forests (TMCFs) that are tightly coupled to the atmospheric hydrologic cycle. Small-scale shifts in temperature and precipitation could have serious ecological consequences. Therefore, this makes TMCFs an interesting ecosystem to see the effects African Dust (AD) might have on cloud formation and precipitation. As part of the Puerto Rico African Dust and Clouds Study (PRADACS) cloud and rain water samples for subsequent chemical analysis were collected at Pico del Este (PE) station in Luquillo, PR (1051 masl) during summer 2011. At PE, two cloud collectors (i.e., single stage (Aluminum version) and 2-stage (Teflon version) Caltech Active Strand Cloudwater Collector (CASCC)), and a rainwater collector were operated. Measurements such as the liquid water content (LWC), pH, conductivity., and composition of single particles using an aerosol time of flight mass spectrometer (ATOFMS) were performed. Preliminary results showed that days with the influence of African dust (AD), had LWC values that ranged from 300 to 500 mg/m3, pH values up to 5.7,, and conductivity up to 180 ?S/cm. The ATOFMS showed titanium and iron ions, suggesting the presence of AD as well as, occasionally, sulfate and nitrate ions suggesting the influence of anthropogenic pollution. Results on the chemical composition and the physical properties of cloud, rainwater, and aerosol for the inorganic as well as the organic fraction and how these properties change for the different air masses observed will also be presented.

Torres, E.; Valle Diaz, C. J.; Zurcher, F.; Lee, T.; Collett, J. L.; Fitzgerald, E.; Cuadra, L.; Prather, K. A.; Mayol-Bracero, O. L.

2011-12-01

245

The New York City bus terminal diesel emissions study measurement and collection of diesel exhaust for chemical characterization and mutagenic activity  

SciTech Connect

In order to evaluate the impact of emission from heavy-duty diesel engines on the mutagenicity of ambient air, this study was designed to compare the mutagenic activity of size-fractionated airborne particles collected inside and outside a large bus terminal. Most diesel exhaust studies have been performed in a laboratory setting. The NYC Port Authority Bus Terminal Study, on the other hand, was designed to collect, measure, chemically characterize, and bioassay diesel exhaust as it exists after becoming resident in the surrounding air. Chamber studies have demonstrated that some of the organic compounds associated with diesel exhaust undergo atmospheric transformation when subjected to ultraviolet light in combination with other pollutants such as ozone, nitrogen dioxide, and reactive hydrocarbons. These studies have also shown that the mutagenic response changes with the transformations. A high ambient loading of the emissions aerosol was chosen for the study in order to maximize the amount of information which could be acquired on the character, ambient exposure level, and potential health effects associated with diesel exhaust.

Burton, R.M.; Suggs, J.C.; Jungers, R.H.; Lewtas, J. (U.S. Environmental Protection Agency, Research Triangle Park, NC (US))

1987-01-01

246

Synthesis, structural, physico-chemical and biological properties of new palladium(II) complexes with 2,6-dimethyl-4-nitropyridine  

Microsoft Academic Search

This paper describes the synthesis and properties of two new palladium(II) complexes with 2,6-dimethyl-4-nitro-pyridine (dmnp): mononuclear [Pd(dmnp)2Cl2] and dinuclear [Pd2(dmnp)2Cl4]. Complexes were characterized on the basis of chemical and chromatographic analyses, MS and conductometric measurements, as well as by IR and NMR (1H and 13C) spectral studies. The crystal structures of ligand and mononuclear complex, trans-dichlorobis(2,6-dimethyl-4-nitro-pyridine)palladium(II), were determined by three-dimensional

Janina Kuduk-Jaworska; Aniela Puszko; Maria Kubiak; Marzena Pe?czy?ska

2004-01-01

247

Electronic structure and chemical bonding of the electron-poor II-V semiconductors ZnSb and ZnAs  

Microsoft Academic Search

The binary compounds ZnSb and ZnAs with the CdSb structure are semiconductors (II-V), although the average electron concentration (3.5 per atom) is lower than that of the tetrahedrally bonded III-V and II-VI archetype systems (four per atom). We report a detailed electronic structure and chemical bonding analysis for ZnSb and ZnAs based on first-principles calculations. ZnSb and ZnAs are compared

Daryn Benson; Otto F. Sankey; Ulrich Häussermann

2011-01-01

248

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

249

77 FR 55473 - Agency Information Collection Activities; Renewal of a Currently Approved Collection; Comment...  

Federal Register 2010, 2011, 2012, 2013

...Collection; Comment Request; Basel II Recordkeeping and Disclosures AGENCY: Federal Deposit...the currently approved Basel II--Recordkeeping and Disclosures information collection...Title: Basel II: Disclosures and Recordkeeping. OMB Number: 3064-0153....

2012-09-10

250

Reaction centers of photosystem II with a chemically-modified pigment composition: exchange of pheophytins with 13 1-deoxo-13 1-hydroxy-pheophytin a  

Microsoft Academic Search

Isolated reaction centers of photosystem II with an altered pigment content were obtained by chemical exchange of the native pheophytin a molecules with externally added 131-deoxo-131-hydroxy-pheophytin a. Judged from a comparison of the absorption spectra and photochemical activities of exchanged and control reaction centers, 70–80% of the pheophytin molecules active in charge separation are replaced by 131-deoxo-131-hydroxy-pheophytin a after double

A. Ya. Shkuropatov; R. A. Khatypov; V. A. Shkuropatova; M. G. Zvereva; T. G. Owens; V. A. Shuvalov

1999-01-01

251

A forgotten collection: the Libyan ethnobotanical exhibits (1912-14) by A. Trotter at the Museum O. Comes at the University Federico II in Naples, Italy  

PubMed Central

Background The Ethnobotanical Collection from the Libyan territories of the botanist Alessandro Trotter is included in the Oratio Comes Botanical Museum at the Faculty of Agraria at the University Federico II in Naples. Trotter explored different territories of Libya, mainly Tripolitania, between 1912-1924, collecting plant specimens and the drugs most frequently sold in the markets. The Libyan herbarium currently includes over 2300 sheets of mounted and accessioned plants. The drugs, mostly acquired by Trotter from Tripolitanian markets, were identified and packed in 87 paper sheets or boxes. Trotter added ethnobotanical information for each species when available. Methods A database of the herbarium species and the drugs has been carried out, after a taxonomic update. Nomenclature has been revised according to the African flowering plants database and the World Checklist of selected plant families, and a comparison with currently available ethnopharmacological data from North African has been attempted. Results In this study, ethnopharmacological data related to about 80 species of flowering plants and to 4 lichens are presented. The plants are mainly from Mediterranean or Sub-Saharan habitats and belong to 37 different families; Lamiaceae was the most cited family, with 10 accessions. Generally, the aerial parts of the plants are the most frequently used (28 species), followed by leaves (15 species), flowers and seeds (9 species), fruits (7 species) and hypogean organs (roots, rhizomes, tubers: 5 species). Plants were generally processed in very simple ways: infusion or decoction of the plants were prepared and orally administered or used for topical applications. A wide range of conditions was treated, ranging from mental disorders to skin affections. All the organs of human body are considered, but the pathologies of gastro-intestinal tract, respiratory system and those related to traumatic accidents were the most frequently mentioned. The comparison with the recent ethnopharmacological research in Maghreb and its neighboring countries reveals a high correspondence; almost all the plants cited by Trotter are still used in the folk medicine of at least one of the North African countries, and the therapeutic uses of each plant appear consistent over time. Conclusions The information collected by Trotter is an important contribution to tracing plant utilization in Libyan folk medicine over the last century.

2012-01-01

252

Chemical genomic screening of a Saccharomyces cerevisiae genomewide mutant collection reveals genes required for defense against four antimicrobial peptides derived from proteins found in human saliva.  

PubMed

To compare the effects of four antimicrobial peptides (MUC7 12-mer, histatin 12-mer, cathelicidin KR20, and a peptide containing lactoferricin amino acids 1 to 11) on the yeast Saccharomyces cerevisiae, we employed a genomewide fitness screen of combined collections of mutants with homozygous deletions of nonessential genes and heterozygous deletions of essential genes. When an arbitrary fitness score cutoffs of 1 (indicating a fitness defect, or hypersensitivity) and -1 (indicating a fitness gain, or resistance) was used, 425 of the 5,902 mutants tested exhibited altered fitness when treated with at least one peptide. Functional analysis of the 425 strains revealed enrichment among the identified deletions in gene groups associated with the Gene Ontology (GO) terms "ribosomal subunit," "ribosome biogenesis," "protein glycosylation," "vacuolar transport," "Golgi vesicle transport," "negative regulation of transcription," and others. Fitness profiles of all four tested peptides were highly similar, particularly among mutant strains exhibiting the greatest fitness defects. The latter group included deletions in several genes involved in induction of the RIM101 signaling pathway, including several components of the ESCRT sorting machinery. The RIM101 signaling regulates response of yeasts to alkaline and neutral pH and high salts, and our data indicate that this pathway also plays a prominent role in regulating protective measures against all four tested peptides. In summary, the results of the chemical genomic screens of S. cerevisiae mutant collection suggest that the four antimicrobial peptides, despite their differences in structure and physical properties, share many interactions with S. cerevisiae cells and consequently a high degree of similarity between their modes of action. PMID:23208710

Lis, Maciej; Bhatt, Sanjay; Schoenly, Nathan E; Lee, Anna Y; Nislow, Corey; Bobek, Libuse A

2012-12-03

253

Long-term observation of water-soluble chemical components and acid-digested metals in the total suspended particles collected at Okinawa, Japan  

NASA Astrophysics Data System (ADS)

The economic growth and population increase in recent Asia have been increasing 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. 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 is ideal in observing East Asia's air quality 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 clean air and can be compared with continental air masses which have been affected by anthropogenic activities. We collected total suspended particles (TSP) on quartz filters by using a high volume air sampler at the Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS), Okinawa, Japan during August 2005 and August 2010. Sampling duration was one week for each sample. We determined the concentrations of water-soluble anions, cations, water-soluble organic carbon (WSOC) and acid-digested metals in TSP samples using ion chromatography, atomic absorption spectrometry, total organic carbon analyzer and Inductively Coupled Plasma Mass spectrometry (ICP-MS), respectively. Seasonal variation of water-soluble chemical components and acid-digested metals showed that the concentrations were the lowest 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 and acid-digested metals were much higher compared to the other directions, suggesting long-range transport of air pollutants from Asian continent. Also, when the air mass came from Asian continent (75-100% dominant), the mean concentrations of non-sea salt sulfate and nitrate increased ca. 1.8 times and ca. 3.7 times, respectively between 2005 and 2010, and the ratio of nitrate to non-sea salt sulfate increased ca. 50% which suggested that automobile exhaust emission increased. In addition, the concentration of soil-originated components such as iron and aluminum increased ca. 2.6 times and ca. 3.0 times, suggesting a probable desertification. We also report the calculated background concentrations of water-soluble chemical components and acid-digested metals at Okinawa, Japan.

Handa, D.; Okada, K.; Kuroki, Y.; Nakama, Y.; Nakajima, H.; Somada, Y.; Ijyu, M.; Azechi, S.; Oshiro, Y.; Nakaema, F.; Miyagi, Y.; Arakaki, T.; Tanahara, A.

2011-12-01

254

Effects of Chemical Sympathectomy on Angiotensin II-Induced Neointimal Growth in the Balloon-Injured Rat Carotid Artery  

Microsoft Academic Search

To investigate the role of the sympathetic nervous system in angiotensin II (AngII)-stimulated medial and neointimal smooth muscle cell (SMC) replication, we sympathectomized rats with 6-hydroxydopamine (6-OHDA) in which the left carotid artery was injured by a balloon catheter. Balloon injury is associated with a loss of specific [3H]-prazosin binding. AngII (250 ng\\/kg\\/min), infused 2 weeks after balloon injury of

Richard H. J. Bruijns; Ellen M. van Kleef; Jos F. M. Smits; Jo G. R. De Mey; Mat J. A. P. Daemen

1998-01-01

255

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

256

Manganese (II) induces chemical hypoxia by inhibiting HIF-prolyl hydroxylase: Implication in manganese-induced pulmonary inflammation  

SciTech Connect

Manganese (II), a transition metal, causes pulmonary inflammation upon environmental or occupational inhalation in excess. We investigated a potential molecular mechanism underlying manganese-induced pulmonary inflammation. Manganese (II) delayed HIF-1{alpha} protein disappearance, which occurred by inhibiting HIF-prolyl hydroxylase (HPH), the key enzyme for HIF-1{alpha} hydroxylation and subsequent von Hippel-Lindau(VHL)-dependent HIF-1{alpha} degradation. HPH inhibition by manganese (II) was neutralized significantly by elevated dose of iron. Consistent with this, the induction of cellular HIF-1{alpha} protein by manganese (II) was abolished by pretreatment with iron. Manganese (II) induced the HIF-1 target gene involved in pulmonary inflammation, vascular endothelial growth factor (VEGF), in lung carcinoma cell lines. The induction of VEGF was dependent on HIF-1. Manganese-induced VEGF promoted tube formation of HUVEC. Taken together, these data suggest that HIF-1 may be a potential mediator of manganese-induced pulmonary inflammation.

Han, Jeongoh [Laboratory of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Busan, 609-735 (Korea, Republic of); Lee, Jong-Suk [Laboratory of Physiology, College of Pharmacy, Yeungnam University, Gyeongsan (Korea, Republic of); Choi, Daekyu; Lee, Youna; Hong, Sungchae; Choi, Jungyun; Han, Songyi [Laboratory of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Busan, 609-735 (Korea, Republic of); Ko, Yujin; Kim, Jung-Ae [Laboratory of Physiology, College of Pharmacy, Yeungnam University, Gyeongsan (Korea, Republic of); Mi Kim, Young [Medicinal Chemistry, College of Pharmacy, Pusan National University, Busan (Korea, Republic of); Jung, Yunjin [Laboratory of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Busan, 609-735 (Korea, Republic of)], E-mail: jungy@pusan.ac.kr

2009-03-15

257

Copper(II) complexes with 2NO and 3N donor ligands: synthesis, structures and chemical nuclease and anticancer activities.  

PubMed

A series of water soluble copper(II) complexes of the types [Cu(L)Cl] 1-2, where LH is 2-(2-(1H-benzimidazol-2-yl)ethyliminomethyl)phenol (H(L1)), and 2-(2-(1H-benzimidazol-2-yl)-ethyliminomethyl)-4-methylphenol (H(L2)), and [Cu(L)Cl2] 3-6, where L is (2-pyridin-2-yl-ethyl)pyridin-2-ylmethyleneamine (L3), 2-(1H-benzimidazol-2-yl)ethylpyridin-2-yl-methyleneamine (L4), 2-(1H-benzimidazol-2-yl)ethyl(1H-imidazol-2-ylmethylene)amine (L5), and 2-(1H-benzimidazol-2-yl)ethyl-(4,4a-dihydroquinolin-2-ylmethylene)amine (L6), have been isolated and characterized by elemental analysis, electronic absorption, ESI-MS and EPR spectral techniques and the electrochemical method. The single crystal X-ray structures of [Cu(L1)Cl] 1 and [Cu(L2)Cl] 2 possess a distorted square-based coordination geometry while [Cu(L4)Cl2] 4 and [Cu(L6)Cl2] 6 possess a distorted trigonal bipyramidal coordination geometry. Both absorption spectral titration and an EthBr displacement assay reveal that all the complexes bind with calf thymus (CT) DNA through covalent mode of DNA interaction involving the replacement of an easily removable chloride ion with DNA nucleobases. All the complexes exhibit oxidative cleavage of supercoiled (SC) plasmid DNA in the presence of hydrogen peroxide as an activator. It is remarkable that at 50 ?M concentration 5 and 6 completely degrade SC DNA into undetectable minor fragments and thus they act as efficient chemical nucleases. All the complexes are remarkable in displaying cytotoxicity against the HBL-100 human breast cancer cell line with potency more than that of the widely used drug cisplatin and hence they have the potential to act as promising anticancer drugs. Interestingly, they are non-toxic to normal cell lymphocytes isolated from human blood samples, revealing that they are selective in killing only the cancer cells. PMID:23612925

Rajarajeswari, Chandrasekaran; Loganathan, Rangasamy; Palaniandavar, Mallayan; Suresh, Eringathodi; Riyasdeen, Anvarbatcha; Akbarsha, Mohamad Abdulkadhar

2013-04-24

258

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

2013-06-10

259

Chemical changes of kenaf core binderless boards during hot pressing (II): effects on the binderless board properties  

Microsoft Academic Search

To provide basic information on self-bonding in kenaf core binderless boards, a series of chemical analyses was conducted\\u000a on binderless boards and their chemical changes during hot pressing were examined in our previous study. In this study, binderless\\u000a boards were manufactured under conditions that may accelerate the supposed chemical changes to investigate their effect on\\u000a the board properties. First, to

Nobuhisa Okuda; Keko Hori; Masatoshi Sato

2006-01-01

260

Physico-chemical studies and CO adsorption on zeolite-encapsulated MnII, MnIII hydrazone complexes  

NASA Astrophysics Data System (ADS)

Complexes of Mn(II) and Mn(III) with N2O3 hydrazone ligand derived from salicylaldehyde and benzenesulphonylhydrazide have been encapsulated in zeolite Y- supercages by a diffusion method. The synthesized new materials have been characterized by combination of elemental analysis, FT-IR, UV vis., magnetic measurements, XRD, thermal analysis (TG, DTG and DTA), as well as surface area measurements and nitrogen adsorption studies. Investigation of the stereochemistry of these incorporated chelates pointed out that, Mn(II) complex is tetrahedral with involvement of zeolite oxygen in coordination meanwhile Mn(III) complex has octahedral configuration without contribution of the lattice oxygen. The intrazeolitic hydrazone complexes are thermally stable up to 1000 °C without decomposition. Catalytic activity towards CO adsorption for these zeolite encapsulated complexes has been investigated and compared with MnII-Y using in situ FT-IR spectroscopy. The results revealed that, MnII(SBSH)/Y and MnIII(SBSH)/Y give an elementary peak near 1728 cm-1 indicating a selectivity to form COOH species while MnII-Y catalyst gives a broad band in the region of 1765 1560 cm-1 assigned to different (COOH) and carbonates species. On the other hand, the in situ FT-IR data indicate that MnII(SBSH)/Y and MnIII(SBSH)/Y can be used as reactive catalysts in water gas shift reaction (WGSR).

Ahmed, Ayman H.

2007-08-01

261

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

262

EXTRAGALACTIC CHEMICAL ABUNDANCES: DO H II REGIONS AND YOUNG STARS TELL THE SAME STORY? THE CASE OF THE SPIRAL GALAXY NGC 300  

SciTech Connect

We have obtained new spectrophotometric data for 28 H II regions in the spiral galaxy NGC 300, a member of the nearby Sculptor Group. The detection of several auroral lines, including [O III] {lambda}4363, [S III] {lambda}6312, and [N II] {lambda}5755, has allowed us to measure electron temperatures and direct chemical abundances for the whole sample. We determine for the first time in this galaxy a radial gas-phase oxygen abundance gradient based solely on auroral lines, and obtain the following least-square solution: 12 + log(O/H) = 8.57({+-}0.02) - 0.41({+-}0.03)R/R {sub 25}, where the galactocentric distance is expressed in terms of the isophotal radius R {sub 25}. The characteristic oxygen abundance, measured at 0.4 x R{sub 25}, is 12 + log(O/H) = 8.41. The gradient corresponds to -0.077 {+-} 0.006 dex kpc{sup -1}, and agrees very well with the galactocentric trend in metallicity obtained for 29 B and A supergiants in the same galaxy, -0.081 {+-} 0.011 dex kpc{sup -1}. The intercept of the regression for the nebular data virtually coincides with the intercept obtained from the stellar data, which is 8.59({+-}0.05). This allows little room for depletion of nebular oxygen onto dust grains, although in this kind of comparison we are somewhat limited by systematic uncertainties, such as those related to the atomic parameters used to derive the chemical compositions. We discuss the implications of our result with regard to strong-line abundance indicators commonly used to estimate the chemical compositions of star-forming galaxies, such as R {sub 23}. By applying a few popular calibrations of these indices based on grids of photoionization models on the NGC 300 H II region fluxes, we find metallicities that are higher by 0.3 dex (a factor of 2) or more relative to our nebular (T{sub e} based) and stellar ones. We detect Wolf-Rayet stellar emission features in {approx}1/3 of our H II region spectra, and find that in one of the nebulae hosting these hot stars the ionizing field has a particularly hard spectrum, as gauged by the 'softness' parameter {eta} = (O{sup +}/O{sup ++})/(S{sup +}/S{sup ++}). We suggest that this is related to the presence of an early WN star. By considering a larger sample of extragalactic H II regions we confirm, using direct abundance measurements, previous findings of a metallicity dependence of {eta}, in the sense that softer stellar continua are found at high metallicity.

Bresolin, Fabio; Kudritzki, Rolf-Peter; Urbaneja, Miguel A. [Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Gieren, Wolfgang; Pietrzynski, Grzegorz [Universidad de Concepcion, Departamento de Astronomia, Casilla 160-C, Concepcion (Chile); Carraro, Giovanni [European Southern Observatory, Alonso de Cordova 3107, Santiago (Chile)

2009-07-20

263

Fractionally distilled SRC-I, SRC-II, EDS, H-Coal and ITSL direct coal liquefaction process materials: a comparative summary of chemical analysis and biological testing  

SciTech Connect

This document reports and compares the results compiled from chemical analyses and biological testing of coal liquefaction process materials which were fractionally distilled, after production, into various comparable boiling-point range cuts. Comparative analyses were performed on solvent refined coal (SRC)-I, SRC-II, H-Coal, EDS an integrated two-stage liquefaction (ITSL) distillate materials. Mutagenicity and carcinogenicity assays were conducted in conjunction with chromatographic and mass spectrometric analyses to provide detailed, comparative, chemical and biological assessments. Where possible, results obtained from the distillate cuts are compared to those from coal liquefaction materials with limited boiling ranges. Work reported here was conducted by investigators in the Biology and Chemistry Department at the Pacific Northwest Laboratory (PNL), Richland, WA. 38 refs., 16 figs., 27 tabs.

Wright, C.W.; Later, D.W.; Dauble, D.D.; Wilson, B.W.

1985-07-01

264

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

265

Chemical Shifts and Coupling Constants in Pentafluorophenyl Derivatives. Ii. Application to a Study of Bonding in Selected Compounds.  

National Technical Information Service (NTIS)

The pi interactions within molecules containing the pentafluorophenyl group are examined using the coupling constant-chemical shift relationship as proposed in the preceding paper. The following series, selected from the 73 pentafluorophenyl compounds stu...

M. G. Hogben R. S. Gay A. J. Oliver J. A. J. Thompson W. A. G. Graham

1968-01-01

266

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

267

Oxidative Stress-mediated Chemical Modifications to Biomacromolecules: Mechanism and Implication of Modifications to Human Skin Keratins and Angiotensin II.  

PubMed

  Dysregulated production of reactive oxygen species (ROS) during oxidative stress has been associated with a number of inflammatory and age-related degenerative diseases. ROS can directly react with DNA to form oxidized DNA bases. Direct protein oxidation and carbonylation occur on certain amino acid residues resulting in various post-translational modifications. ROS can also initiate the formation of lipid hydroperoxides, which undergo homolytic decomposition to the ?,?-unsaturated aldehydic bifunctional electrophiles such as 4-oxo-2(E)-nonenal (ONE) and 4-hydroxy-2(E)-nonenal (HNE). Intracellular generation of highly reactive aldehydes can then result in the formation of DNA and protein adducts. ONE-derived heptanone-etheno and HNE-derived propano DNA adducts have been detected and shown to be mutagenic in a variety of biological systems. In addition, ONE and HNE are involved in protein dysfunctions and altered gene regulations through the modification of amino acid residues and crosslinking of proteins. Our recent study on human skin keratins has identified specific K1 methionine residues as the most susceptible sites to oxidation with hydrogen peroxide, which can be potential biomarkers of oxidative skin damage. The reactions of angiotensin (Ang) II with ONE or HNE produced several modified Ang IIs including a novel pyruvamide-Ang II that formed via oxidative decarboxylation of N-terminal aspartic acid. Subsequently, it has been revealed that the oxidative modifications on the N-terminus of Ang II disrupt interactions with Ang II type 1 receptor and aminopeptidase A, which could affect the regulation of cardiovascular function. PMID:24088349

Hwa Lee, Seon

2013-01-01

268

Chromosome aberration and sister chromatid exchange tests in Chinese hamster ovary cells in vitro: II. Results with 20 chemicals  

SciTech Connect

Twenty chemicals were tested for their ability to induce sister chromatid exchanges (SCEs) and chromosomal aberrations (ABs) in cultured Chinese hamster ovary cells (CHO). These chemicals were tested with and without an added metabolic activation system (rat liver S9 fraction). Four chemicals were negative in both assays, 1 induced ABs only, and 15 were positive for SCEs; 6 of these 15 also induced ABs. The effect of cell harvest time on the ability to detect the induction of chromosomal aberrations was examined for six chemicals. Five of these had caused at least one of the following cell cycle delay, aberrations observed in first division metaphase cells in SCE assay, or a weak response in the standard AB assay (10-12-hr growth period). Three chemicals, chlorinated trisodium phosphate, 1,2-dibromo-3-chloropropane, and tetrakis(hydroxymethyl)phosphonium chloride, were positive using both the standard and extended harvest times. N-Nitrosodimethylamine and diphenhydramine HCl were only positive using an extended harvest time, and malonaldehyde was negative using both standard and extended harvest times.

Loveday, K.S.; Lugo, M.H. (American Biogenecis Corp., Woburn, MA (USA)); Resnick, M.A.; Anderson, B.E.; Zeiger, E. (Institute of Environmental Health Sciences, Research Triangle Park, NC (USA))

1989-01-01

269

Solution chemical properties and catecholase-like activity of the copper(II)-Ac-His-His-Gly-His-OH system, a relevant functional model for copper containing oxidases.  

PubMed

The solution chemical properties, superoxide dismutase and catecholase activity of the copper(ii)-Ac-His-His-Gly-His-OH (hhgh) complexes were studied to identify functional and structural models of copper-containing oxidases. The solution speciation was determined in the pH range 3-11 by two independent methods (potentiometry and pH-dependent EPR measurements). The results obtained by the two methods agree very well with each other and show the formation of differently protonated CuH(x)L complexes (where x= 2 ,1, 0, -1, -2, -3) in aqueous solution. The spectroscopic (UV-Vis, CD, EPR) data indicate that the coordination of the imidazole rings is a determinant factor in all these complexes. Amide coordinated complexes are dominant only above pH 8. This offers excellent possibilities for structural/functional modelling of copper(ii) containing metalloenzymes. Indeed, the {3N(im)} coordinated CuL species (pH = 6-7) has efficient superoxide dismutase-like activity. The {3N(im),OH(-)} coordinated CuH(-1)L possesses outstanding activity to catalyze the oxidation of 3,5-di-tert-butylcatechol (H(2)dtbc) by dioxygen in 86 wt% methanol-water, providing the first example that copper(ii)-peptide complexes are able to mimic copper containing oxidases. PMID:16172644

Jancsó, A; Paksi, Z; Jakab, N; Gyurcsik, B; Rockenbauer, A; Gajda, T

2005-08-19

270

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

271

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

272

Highly sensitive sensing of zinc(II) by development and characterization of a PVC-based fluorescent chemical sensor.  

PubMed

A sensor membrane with excellent performance based on 1-methyl-1-phenyl-3-[1-hydroxyimino-2-(succinimido)ethyl]cyclobutane has been developed for the determination of zinc(II) ions. The sensing membrane is capable of determining zinc(II) with an outstanding high selectivity over a dynamic range between 8.0×10(-8) and 1.6×10(-4) mol L(-1) with a limit of detection of 2.5×10(-8) mol L(-1) (1.6 ?g L(-1)). It can be easily and completely regenerated by using 0.1 mol L(-1) EDTA solution. The optical sensor developed here was found to be stable, cost effective, easy to prepare, and has unique selectivity towards Zn(2+) ion with respect to common metal ions. The proposed sensor was then applied for the determination of zinc in tap water and hair samples with satisfactory results. PMID:21257342

Aksuner, Nur; Henden, Emur; Yenigul, Berrin; Yilmaz, Ibrahim; Cukurovali, Alaaddin

2010-12-24

273

Giant polarized optical properties in type-II ZnTe\\/CdSemultiple quantum wells induced by interface chemical bonds  

Microsoft Academic Search

Photoluminescence (PL) and photoconductivity (PC) spectra were studied in type-II ZnTe\\/CdSe multiple quantum wells. It was found that the PL spectrum exhibits a strong in-plane polarization with respect to 011 axis with polarization degree up to 30%. The degree of polarization does not depend on the excitation intensity and temperature, which excludes extrinsic mechanisms related to the observed in-plane anisotropy.

Y. F. Chen; W. S. Su; M. H. Ya; Y. S. Chiu

2004-01-01

274

Polarized optical properties in type-II ZnTe\\/CdSe multiple quantum wells induced by interface chemical bonds  

Microsoft Academic Search

Photoluminescence (PL) and photoconductivity (PC) spectra were studied in type-II ZnTe\\/CdSe multiple quantum wells. It was found that the PL spectrum exhibits a strong in-plane polarization with respect to axis with a polarization degree up to 30%. The degree of polarization does not depend on the excitation intensity and temperature, which excludes extrinsic mechanisms related to the observed in-plane anisotropy.

W. S. Su; M. H. Ya; Y. S. Chiu; Y. F. Chen

2002-01-01

275

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)

1995-10-01

276

Chemical Modifications of Douglas Fir Bark, a Lignocellulosic By?product—Enhancement of Their Lead(II) Binding Capacities  

Microsoft Academic Search

Chemical modification of Douglas fir bark and its subsequent utilization in adsorption of Pb from aqueous solutions was investigated. We developed a new solvent?free approach to enhance the natural properties of bark by utilizing polyfunctional groups covalently attached at their surface. The hydroxyl groups of their polysaccharide moiety were functionalized by periodate oxidation and derivatized via reductive amination in presence

Vincent Gloaguen; Robert Granet; Michel Guilloton; Pierre Krausz

2005-01-01

277

Identification of QTLs influencing wood property traits in loblolly pine ( Pinus taeda L.). II. Chemical wood properties.  

PubMed

Chemical wood property traits were analyzed for the presence of quantitative trait loci (QTLs) in a three-generation outbred pedigree of loblolly pine ( Pinus taeda L.). These traits were assayed using pyrolysis molecular beam mass spectrometry and include mass spectrum peak intensities associated with carbohydrates, alpha-cellulose and hemicellulose sugars, and lignin. Models for projection to latent structures (PLS) were used to also estimate the chemical composition of cell walls (i.e., alpha-cellulose, galactan and lignin) from mass spectrum data using multivariate regression. Both earlywood and latewood fractions from the fifth annual ring were analyzed for each trait. An interval mapping approach designed for an outbred pedigree was used to estimate the number of QTLs, the magnitude of QTL effects, and their genomic position. Eight unique QTLs influencing cell wall chemistry were detected from multiple peak intensities and/or PLS estimates using the one- and two-QTL models. Significant differences in chemical contents were observed among the populations from North Carolina vs Oklahoma, and results from QTLxenvironment analyses suggest that QTLs interact with environmental location. QTLs should be verified in larger experiments and in different genetic and environmental backgrounds. QTL mapping will help towards eventually identifying genes having a major effect on chemical wood properties. PMID:12582689

Sewell, M. M.; Davis, M. F.; Tuskan, G. A.; Wheeler, N. C.; Elam, C. C.; Bassoni, D. L.; Neale, D. B.

2002-02-01

278

Chemical Products in the Home, Workshop and Garden. Proceed with Caution; Consumer Safety in the Home, II.  

ERIC Educational Resources Information Center

The average home has chemical products to clean floors, kill insects, clean ovens, thin paint, remove grease, and perform countless other chores. Many consumers remain unaware of the dangers these products bring into the home. This booklet provides information on the safe use, storage, and disposal of these products. The compounds found in…

Saskatchewan Consumer and Commercial Affairs, Regina.

279

Studies of Chemical Shift Anisotropy in Liquid-Crystal Solvents. II. Theoretical Calculations for the Methyl Halides  

Microsoft Academic Search

Experimentally determined values of the proton chemical-shift anisotropy for the methyl halides have been used to test simple phenomenological theories which have been proposed to account for proton magnetic shielding. It is shown that the frequently used magnetic dipole model predicts that the long-range contribution to the proton shielding anisotropy should largely depend on the average neighbor magnetic susceptibility. Anisotropies

Gerald P. Ceasar; Benjamin P. Dailey

1969-01-01

280

Chemical and Morphological Studies of Bacterial Spore Formation: II. Spore and Parasporal Protein Formation in Bacillus cereus var. Alesti  

Microsoft Academic Search

The development of both the spore and parasporal protein crystal of Bacillus cereus var. alesti was followed using chemical and cytological techniques. The changes which led to the formation of the fore-spore were similar to those already described for Bacillus cereus. However, adjacent to the developing fore-spore a small inclusion became discernible in phase contrast. This protein inclusion dur- ing

I. ELIZABETH YOUNG; PHILIP C. FITZ-JAMES

1959-01-01

281

Chemical Products in the Home, Workshop and Garden. Proceed with Caution; Consumer Safety in the Home, II.  

ERIC Educational Resources Information Center

|The average home has chemical products to clean floors, kill insects, clean ovens, thin paint, remove grease, and perform countless other chores. Many consumers remain unaware of the dangers these products bring into the home. This booklet provides information on the safe use, storage, and disposal of these products. The compounds found in…

Saskatchewan Consumer and Commercial Affairs, Regina.

282

Chemical evolution of the Milky Way Galaxy. II. On the origin of scatter in the age-metallicity relation  

Microsoft Academic Search

We present a model for chemical evolution of the solar vicinity region taking into account both an irregular rate of unenriched gas infall onto the disk and the self-enrichment of star formation regions with sequential star formation. The evolution of oxygen, iron and deuterium abundances has been followed. It has been found that a present-day and past scatter of oxygen

L. S. Pilyugin; M. G. Edmunds

1996-01-01

283

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

284

Fluid and chemical flux in and out of sediments hosting methane hydrate deposits on Hydrate Ridge, OR, II: Hydrological processes  

Microsoft Academic Search

Multiple, long-term measurements of aqueous and chemical flux through regions of active fluid seeps and gas vents on Hydrate Ridge, Cascadia accretionary prism, were accomplished during 1998 and 1999 as part of the international TECFLUX project. These measurements indicate that flow is highly heterogeneous in both time and space with areas of inflow, outflow, and outflow of fluids of both

M. D Tryon; K. M Brown; M. E Torres

2002-01-01

285

Characterization of Chemical Sputtering Using the Mark II DIMES Porous Plug Injector in Attached and Semi-detached Divertor Plasmas of DIII-D  

SciTech Connect

An improved, self-contained gas injection system for the divertor material evaluation system (DIMES) on DIII-D has been employed for in situ study of chemical erosion in the tokamak divertor environment. To minimize perturbation to local plasma, the Mark II porous plug injector (PPI) releases methane through a porous graphite surface at the outer strike point at a rate precisely controlled by a micro-orifice flow restrictor to be approximately equal as that predicted for intrinsic chemical sputtering. Effective photon efficiencies resulting from CH(4) are found to be 58 +/- 12 in an attached divertor (n(e) similar to 1.5 x 10(13)/cm(3), T(e) similar to 25 eV, T(surf)similar to 450 K), and 94 +/- 20 in a semi-detached cold divertor (n(e) similar to 6.0 x 10(13)/cm(3), T(e) similar to 2-3 eV, T(surf) similar to 350 K). These values are significantly more than previous measurements in similar plasma conditions, indicating the importance of the injection rate and local re-erosion for the integrity of this analysis. The contribution of chemical versus physical sputtering to the source of C(+) at the target is assessed through simultaneous measurement of CII line, and CD plus CH-band emissions during release of CH(4) from the Pill, then compared with that seen in intrinsic sputtering. (C) 2009 Elsevier B.V. All rights reserved.

McLean, A. G. [University of Toronto Institute for Aerospace Studies; Davis, J. W. [University of Toronto Institute for Aerospace Studies; Stangeby, P. C. [University of Toronto Institute for Aerospace Studies; Allen, S. L. [Lawrence Livermore National Laboratory (LLNL); Boedo, J. A. [University of California, San Diego; Bray, B. D. [General Atomics, San Diego; Brezinsek, S. [Forschungszentrum Julich, Julich, Germany; Brooks, N. H. [General Atomics, San Diego; Fenstermacher, M. E. [Lawrence Livermore National Laboratory (LLNL); Groth, M. [Lawrence Livermore National Laboratory (LLNL); Haasz, A. A. [University of Toronto Institute for Aerospace Studies; Hollmann, E. M. [University of California, San Diego; Isler, Ralph C [ORNL; Lasnier, C. J. [Lawrence Livermore National Laboratory (LLNL); Mu, Y. [University of Toronto Institute for Aerospace Studies; Petrie, T. W. [General Atomics, San Diego; Rudakov, D. L. [University of California, San Diego; Watkins, J. G. [Sandia National Laboratories (SNL); West, W. P. [General Atomics, San Diego; Whyte, D. G. [Massachusetts Institute of Technology (MIT); Wong, C. P. C. [General Atomics, San Diego

2009-01-01

286

Responsible Collecting  

NSDL National Science Digital Library

This article, part of Biodiversity Counts, examines how to responsibly collect and keep specimens. The article discusses the reasons why collecting specimens is important and the behaviors and attitudes that define responsible collecting for both scientists and students.

287

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

288

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

289

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

290

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

291

Chemical reactions involved in the deep fat frying of foods. II. Identification of acidic volatile decomposition products of corn oil  

Microsoft Academic Search

Chemical identification of the volatile decomposition products (VDP) produced by fats and oils under conditions of deep fat\\u000a frying is important for the elucidation of the mechanisms of thermal oxidation, for the study of their effects upon human\\u000a nutrition, and for their contribution to the deep fat fried flavor of foods. The acidic VDP produced by corn oil maintained\\u000a at

Tsukasa Kawada; R. G. Krishnamurthy; B. D. Mookherjee; S. S. Chang

1967-01-01

292

MULTIDIMENSIONAL CHEMICAL MODELING OF YOUNG STELLAR OBJECTS. II. IRRADIATED OUTFLOW WALLS IN A HIGH-MASS STAR-FORMING REGION  

SciTech Connect

Observations of the high-mass star-forming region AFGL 2591 reveal a large abundance of CO{sup +}, a molecule known to be enhanced by far-ultraviolet (FUV) and X-ray irradiation. In chemical models assuming a spherically symmetric envelope, the volume of gas irradiated by protostellar FUV radiation is very small due to the high extinction by dust. The abundance of CO{sup +} is thus underpredicted by orders of magnitude. In a more realistic model, FUV photons can escape through an outflow region and irradiate gas at the border to the envelope. Thus, we introduce the first two-dimensional axisymmetric chemical model of the envelope of a high-mass star-forming region to explain the CO{sup +} observations as a prototypical FUV tracer. The model assumes an axisymmetric power-law density structure with a cavity due to the outflow. The local FUV flux is calculated by a Monte Carlo radiative transfer code taking scattering on dust into account. A grid of precalculated chemical abundances, introduced in the first part of this series of papers, is used to quickly interpolate chemical abundances. This approach allows us to calculate the temperature structure of the FUV-heated outflow walls self-consistently with the chemistry. Synthetic maps of the line flux are calculated using a raytracer code. Single-dish and interferometric observations are simulated and the model results are compared to published and new JCMT and Submillimeter Array (SMA) observations. The two-dimensional model of AFGL 2591 is able to reproduce the JCMT single-dish observations and also explains the nondetection by the SMA. We conclude that the observed CO{sup +} line flux and its narrow width can be interpreted by emission from the warm and dense outflow walls irradiated by protostellar FUV radiation.

Bruderer, S.; Benz, A.O. [Institute of Astronomy, ETH Zurich, CH-8093 Zurich (Switzerland); Doty, S. D. [Department of Physics and Astronomy, Denison University, Granville, OH 43023 (United States); Van Dishoeck, E. F. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Bourke, T. L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)], E-mail: simonbr@astro.phys.ethz.ch

2009-07-20

293

Identification of QTLs influencing wood property traits in loblolly pine ( Pinus taeda L.). II. Chemical wood properties  

Microsoft Academic Search

Chemical wood property traits were analyzed for the presence of quantitative trait loci (QTLs) in a three-generation outbred\\u000a pedigree of loblolly pine (Pinus taeda L.). These traits were assayed using pyrolysis molecular beam mass spectrometry and include mass spectrum peak intensities\\u000a associated with carbohydrates, ?-cellulose and hemicellulose sugars, and lignin. Models for projection to latent structures\\u000a (PLS) were used to

M. M. Sewell; M. F. Davis; G. A. Tuskan; N. C. Wheeler; C. C. Elam; D. L. Bassoni; D. B. Neale

2002-01-01

294

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

295

Collection Management  

Microsoft Academic Search

The OCLC ICAS (Interactive Collection Analysis System) offers a means to effectively document the state of a foreign language collection as well as a means to systematically develop a collection for the future. Data were collected from the ICAS compact disc generated by OCLC\\/WLN from WorldCat holdings and information from the library's integrated library system (ILS). Data were used to

Pauline C. Williams; Brent N. Halvonik

2004-01-01

296

Effects of chemical chaperones on partially retarded NaCl cotransporter mutants associated with Gitelman's syndrome in a mouse cortical collecting duct cell line  

Microsoft Academic Search

BACKGROUND: Epithelial cells lining the distal convoluted tubule express the thiazide-sensitive Na-Cl cotransporter (NCC) that is responsible for the reabsorption of 5-10% of the filtered load of Na(+) and Cl(-). Mutations in NCC cause the autosomal recessive renal disorder Gitelman's syndrome (GS). GS mutations give rise to mutant transporters that are either fully (class I) or partially (class II) retarded.

Joke C. de Jong; Peter H. G. M. Willems; Monique Goossens; A. van de Walle; L. P. W. J. van den Heuvel; N. V. A. M. Knoers; R. J. M. Bindels

2004-01-01

297

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

298

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

PubMed

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. PMID:22373387

Li, Li-Gong; Liu, Shu-Man; Luo, Shuai; Yang, Tao; Wang, Li-Jun; Liu, Feng-Qi; Ye, Xiao-Ling; Xu, Bo; Wang, Zhan-Guo

2012-02-28

299

Analytical simulation and PROFAT II: a new methodology and a computer automated tool for fault tree analysis in chemical process industries.  

PubMed

Fault tree analysis (FTA) is based on constructing a hypothetical tree of base events (initiating events) branching into numerous other sub-events, propagating the fault and eventually leading to the top event (accident). It has been a powerful technique used traditionally in identifying hazards in nuclear installations and power industries. As the systematic articulation of the fault tree is associated with assigning probabilities to each fault, the exercise is also sometimes called probabilistic risk assessment. But powerful as this technique is, it is also very cumbersome and costly, limiting its area of application. We have developed a new algorithm based on analytical simulation (named as AS-II), which makes the application of FTA simpler, quicker, and cheaper; thus opening up the possibility of its wider use in risk assessment in chemical process industries. Based on the methodology we have developed a computer-automated tool. The details are presented in this paper. PMID:10828384

Khan, F I; Abbasi, S A

2000-07-10

300

Summary of photo-id information of blue whales collected by JARPA\\/JARPA II and preliminary analysis of matches in the feeding grounds  

Microsoft Academic Search

This paper summarizes the information on photo-identification of blue whales obtained by JARPA\\/JARPA II surveys in Antarctic Areas IIIE, IV, V and VIW during the austral summer seasons from 1992\\/93 to 2008\\/09. There are a total of 476 pictures of blue whales in the photo-id catalogue held by the Institute of Cetacean Research, which were selected from the total obtained.

Koji Matsuoka; Luis A. Pastene

301

H+ATPase Activity in Collecting Duct Segments in Protein-Deprived Rats – Role of Angiotensin II on Its Regulation  

Microsoft Academic Search

Background: Enhanced expression of the genes that encode for components of the renin-angiotensin system (RAS) has been exhibited in low-protein-fed (LP) rats. We examined distal proton secretion in LP rats through the activity of H+-ATPase on microdissected CCD, OMCD and IMCD segments. The effect of angiotensin II AT1 receptor inhibition and protein recovery (24% protein) on H+-ATPase activity was studied.

Patricia G. Vallés; Liliana Carrizo; Alicia Seltzer; Walter Manucha

2005-01-01

302

Effective Nuclear Charge and Chemical Shifts in X-Ray Absorption Spectra of Polymeric Copper(II) Salicylhydroxamates  

NASA Astrophysics Data System (ADS)

Edge shifts, \\varDelta E, and effective nuclear charges, Zeff, for several polymeric copper(II) complexes of salicylhydroxamic acids have been estimated from copper K-absorption discontinuity using a 40 cm curved crystal spectrograph. The shifts show a parabolic dependence on the effective atomic charge, Zeff, of copper, indicating that an expression of the type \\varDelta E{=}aZeff+b(Zeff)2, where Zeff is the effective atomic charge on the atom in a binary compound, is equally applicable to the complex systems. Finally, the XANES is analyzed critically in terms of edge shifts as well as of effective nuclear charge. Increase of the edge shift due to metal-metal interaction is not observed in the present case.

Khadikar, Padmakar V.; Mangelson, Nolan F.; Pandharkar, Sadhana P.

1989-04-01

303

Antagonists reversibly reverse chemical LTD induced by group I, group II and group III metabotropic glutamate receptors.  

PubMed

Metabotropic glutamate (mGlu) receptors are implicated in many neurological and psychiatric diseases and are the targets of therapeutic agents currently in clinical development. Their activation has diverse effects in the central nervous system (CNS) that includes an involvement in synaptic plasticity. We previously reported that the brief exposure of hippocampal slices to dihydroxyphenylglycine (DHPG) can result in a long-term depression (LTD) of excitatory synaptic transmission. Surprisingly, this LTD could be fully reversed by mGlu receptor antagonists in a manner that was itself fully reversible upon washout of the antagonist. Here, 15 years after the discovery of DHPG-LTD and its reversible reversibility, we summarise these initial findings. We then present new data on DHPG-LTD, which demonstrates that evoked epileptiform activity triggered by activation of group I mGlu receptors can also be reversibly reversed by mGlu receptor antagonists. Furthermore, we show that the phenomenon of reversible reversibility is not specific to group I mGlu receptors. We report that activation of group II mGlu receptors in the temporo-ammonic pathway (TAP) and mossy fibre pathway within the hippocampus and in the cortical input to neurons of the lateral amygdala induces an LTD that is reversed by LY341495, a group II mGlu receptor antagonist. We also show that activation of group III mGlu8 receptors induces an LTD at lateral perforant path inputs to the dentate gyrus and that this LTD is reversed by MDCPG, an mGlu8 receptor antagonist. In conclusion, we have shown that activation of representative members of each of the three groups of mGlu receptors can induce forms of LTD than can be reversed by antagonists, and that in each case washout of the antagonist is associated with the re-establishment of the LTD. This article is part of the Special Issue entitled 'Glutamate Receptor-Dependent Synaptic Plasticity'. PMID:23542080

Lodge, David; Tidball, Patrick; Mercier, Marion S; Lucas, Sarah J; Hanna, Lydia; Ceolin, Laura; Kritikos, Minos; Fitzjohn, Stephen M; Sherwood, John L; Bannister, Neil; Volianskis, Arturas; Jane, David E; Bortolotto, Zuner A; Collingridge, Graham L

2013-03-26

304

The chemical form of selenium affects insulinomimetic properties of the trace element: investigations in type II diabetic dbdb mice.  

PubMed

The objective of the present study was to investigate the effects of oral selenate application in comparison to selenium deficiency and selenite treatment on the development of the diabetic status (glucose tolerance, insulin resistance and activities of glycolytic and gluconeogenic marker enzymes) in dbdb mice, representing a type II diabetic animal model. Therefore 21 adult male dbdb mice were assigned to 3 experimental groups of 7 animals each and put on a selenium deficient diet (< 0.03 mg/kg diet) based on torula yeast. Group 0Se was kept on selenium deficiency for 10 weeks while the mice of the groups SeIV and SeVI were supplemented daily with 15% of their individual LD(50) of sodium selenite or sodium selenate in addition to the diet. After 10 weeks a distinct melioration of the diabetic status indicated by a corrected glucose tolerance and a lowered insulin resistance was measured in selenate treated mice (group SeVI) in comparison to their selenium deficient and selenite treated companions and to their initial status. Activities of the glycolytic marker enzymes hexokinase, phosphofructokinase and pyruvate kinase were increased 1.7 to 3-fold in liver and/or adipose tissue by selenate treatment as compared to mice on selenium deficiency and mice with selenite administration. In contrast selenate treatment (SeVI) repressed the activity of liver pyruvate carboxylase the first enzyme in gluconeogenesis by about 33% in comparison to the selenium deficient (0Se) and selenite treated mice (SeIV). However the current study revealed an insulinomimetic role for selenate (selenium VI) also in type II diabetic animals due to a melioration of insulin resistance. In contrast selenium deficiency and especially selenite (selenium IV) impaired the diabetic status of dbdb mice, demonstrating the need for investigations on the insulinomimetic action of selenium due to the metabolism of different selenium compounds. PMID:14629895

Mueller, Andreas S; Pallauf, Josef; Rafael, Johannes

2003-11-01

305

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

306

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

307

Induced mutagenesis of plasmid and chromosomal genes inserted into the plasmid DNA. II. Mutagenic action of chemical factors  

SciTech Connect

Following the study of the mutagenic action of UV and ..gamma..-radiation on plasmid DNA in vitro, they investigated the induction of mutations under the influence of chemical mutagens on the same DNA of plasmid RSF2124, determining the synthesis of colicine E1 and resistance to ampicillin. The inactivating action of the mutagen was assessed from the yield of transformants resistant to the antibiotic and the mutagenic effect from the loss by colonies of transformants that were capable of releasing colicine into the external medium. In these experiments they mainly used chemical compounds whose mutagenic effect if well known in other systems (transforming and transfecting DNA, microbial viruses). As a result all mutagens tested for their activity were divided into four groups: first group, those exceeding the level of mutagenesis by more than 100-fold above the spontaneous background (hydroxylamine, O-methylhydroxylamine); second group, those exceeding it by a factor of 10 (UV radiation (lambda = 254 nm), W-mutagenesis, ionizing radiation, nitrous acid, mitomycin C); third group, those exceeding it by a factor of <10 (indirect UV mutagenesis, nitrous acid, ..beta..-chloroethyldiethylamine hydrochloride, nitrosoguanidine); fourth group, no mutagenic effect (acridine orange, ethyl methane sulfonate, sodium azide, 0-..beta..-diethylaminoethylhydroxylamine).

Esipova, V.V.; Vedunova, S.L.; Kriviskii, A.S.

1986-02-01

308

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

309

Review of the Department of the Army Pesticide Monitoring Program: Evaluation of Soil and Sediment Samples Collected during Calendar Years 1975-1978. Part II.  

National Technical Information Service (NTIS)

Results of four years monitoring data for soil and sediment collected as part of the Department of the Army Pesticide Monitoring Program are presented. Significant findings are as follows: (a) The various land use stratifications show significant (p=0.05)...

K. L. Olds J. H. Vinopal J. F. Suprock T. M. White

1981-01-01

310

Prognostic significance of the detection of tumour cells in peripheral blood stem cell collections in stage II and III breast cancer patients treated with high-dose therapy.  

PubMed

The purpose of this study was to evaluate the incidence and extent of tumour cell contamination in bone marrow specimens and stem cell collections from 34 breast cancer patients undergoing high-dose therapy as adjuvant treatment, and to determine the prognostic significance for the clinical outcome. Tumour cell contamination was evaluated by flow cytometry using a double-colour test and an anti- Pan cytokeratin (CK) antibody. Two out of 34 (6%) baseline bone marrow specimens, none of seven marrow harvests and nine out of 32 aphereses (28%) mobilised from seven out of 27 patients (26%) contained CK+ cells. Tumour contamination was more frequent in patients with 10 or more involved lymph nodes and in those who received a shorter course of adjuvant chemotherapy before mobilisation. At a median follow-up of 43 months, 24 patients are in complete remission, whereas 10 patients experienced recurrence. Out of the 10 patients who relapsed, five (50%) had CK+ peripheral blood stem cell (PBSC) collections, whereas disease recurrence was seen in only two out of 24 (8%) patients who received CK- products (P=0.02). Moreover, CK+ PBSC collections were associated with a significantly shorter event-free survival and overall survival. CK+ collection is an unfavourable prognostic factor for patients treated with high-dose therapy. Whether the negative impact on clinical outcome depends on reinfusion of tumour cells or whether it simply indicates a larger disease extension is still unclear. PMID:12732886

Patriarca, F; Sacco, C; Sperotto, A; Geromin, A; Damiani, D; Fili, C; Cerno, M; Clochiatti, L; Cartei, G; Fanin, R

2003-05-01

311

Prognostic significance of the detection of tumour cells in peripheral blood stem cell collections in stage II and III breast cancer patients treated with high-dose therapy  

Microsoft Academic Search

The purpose of this study was to evaluate the incidence and extent of tumour cell contamination in bone marrow specimens and stem cell collections from 34 breast cancer patients undergoing high-dose therapy as adjuvant treatment, and to determine the prognostic significance for the clinical outcome. Tumour cell contamination was evaluated by flow cytometry using a double-colour test and an anti-

F Patriarca; C Sacco; A Sperotto; A Geromin; D Damiani; C Fili; M Cerno; L Clochiatti; G Cartei; R Fanin

2003-01-01

312

Integrated chemical\\/biochemical sample collection, pre-concentration, and analysis on a digital microfluidic lab-on-a-chip platform  

Microsoft Academic Search

An ideal on-site chemical\\/biochemical analysis system must be inexpensive, sensitive, fully automated and integrated, reliable, and compatible with a broad range of sa mples. The advent of digital microfluidic lab-on-a-chip (LoC) technology offers such a detection system due to the advantages in portability, reduction of the volumes of the sample and reagents, faster analysis times, increased automation, low power consumption,

R. B. Fair; A. Khlystova; V. Srinivasan; V. K. Pamula; K. N. Weaver

313

Physical and chemical variations within the W3 star-forming region. II. The 345 GHz spectral line survey.  

NASA Astrophysics Data System (ADS)

Results are presented of the 345 GHz spectral survey toward three sources in the W3 Giant Molecular Cloud: W3 IRS4, W3 IRS5 and W3(H_2O). Nearly 90% of the atmospheric window between 334 and 365 GHz has been scanned using the James Clerk Maxwell Telescope down to a noise level of ~80 mK per resolution element. These observations are complemented by a large amount of data in the 230 GHz atmospheric window. From this data set physical conditions and beam-averaged column densities are derived for more than 14 chemically different species (over 24 different isotopes). The physical parameters derived in Paper I (\\cite[Helmich et al. 1994]{ref36}) are confirmed by the analysis of the excitation of other species, although there is evidence that the silicon- and sulfur-bearing molecules exist in a somewhat denser and warmer environment. The densities are high, >= 10^6 cm^{-3}, in the three sources and the kinetic temperatures for the bulk of the gas range from 55 K for IRS4 to 220 K for W3(H_2O). The chemical differences between the three sources are very striking: silicon- and sulfur-bearing molecules such as SiO and SO_2 are prominent toward IRS5, whereas organic molecules like CH_3OH, CH_3OCH_3 and CH_3OCHO are at least an order of magnitude more abundant toward W3(H_2O). Vibrationally excited molecules are also detected toward this source. Only simple molecules are found toward IRS4. The data provide constraints on the amount of deuterium fractionation and the ionization fraction in the observed regions as well. These chemical characteristics are discussed in the context of an evolutionary sequence, in which IRS5 is the youngest, W3(H_2O) somewhat older and IRS4, although still enigmatic, the oldest. The James Clerk Maxwell Telescope is operated by the The Joint Astronomy Centre on behalf of the Particle Physics and Astronomy Research Council of the United Kingdom, the Netherlands Organisation for Scientific Research, and the National Research Council of Canada. Tables 7--12 are also available in electronic form at the CDS via anonymous ftp to cdsarc.u.strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

Helmich, F. P.; van Dishoeck, E. F.

1997-08-01

314

Non-empirical quantum chemical studies on electron transfer reactions in trans- and cis-diamminedichloroplatinum(II) complexes.  

PubMed

The search was made for theoretical confirmation of hypothesis that mechanism of cisplatin cytotoxicity is based on dissociative electron transfer (ET) processes. Applying quantum chemical calculations based on supermolecular approach, the reactions mimicking presumed steps of cisplatin activation were evaluated. The electronic structure of model systems: cis- and transplatin with free electrons, hydrated electrons, and water, was studied by using density functional (DFT) within the Huzinaga basis set and GAUSSIAN-09 package. The respective energy was evaluated with the use of B3LYP density hybrid functional. The calculations were performed for gas phase and water solution; the solvent effects were studied by using the polarizable continuum model. Analysis of the energetic and structural parameters of cisplatin vs. transplatin behavior in the model systems leads to conclusion: there are two possible ways of cisplatin biotransformation, hydrolysis and hydrated electron impact, dependent on the medium redox state. PMID:21559964

Kuduk-Jaworska, Janina; Chojnacki, Henryk; Ja?ski, Jerzy J

2011-05-11

315

Enskog’s kinetic theory of dense gases for chemically reacting binary mixtures, II: Light scattering and sound propagation  

NASA Astrophysics Data System (ADS)

Enskog’s kinetic theory for a symmetric moderately dense reaction A+A?B+B is used to determine Fick’s and Fourier’s law. The transport coefficients of diffusion, thermal-diffusion rate and thermal conductivity are represented graphically for endothermic and exothermic reactions and are analyzed as a function of the activation energy and of the density of the mixture. The Onsager reciprocity relations are numerically investigated and verified. The problems related to sound propagation and light scattering are investigated for such a mixture and it is shown that the influence of chemical reactions on phase velocity, attenuation coefficient and light scattering spectra is more pronounced for rarefied gases although there is a considerable change in these quantities as the mixture becomes denser.

Silva, Adriano W.; Alves, Giselle M.; Marques, Wilson; Kremer, Gilberto M.

2009-02-01

316

Luminescent chemical waves in the Cu(II)-catalyzed oscillatory oxidation of SCN- ions with hydrogen peroxide.  

PubMed

The oscillatory oxidation of thiocyanate ions with hydrogen peroxide, catalyzed by Cu2+ ions in alkaline media, was so far observed as occurring simultaneously in the entire space of the batch or flow reactor. We performed this reaction for the first time in the thin-layer reactor and observed the spatiotemporal course of the above process, in the presence of luminol as the chemiluminescent indicator. A series of luminescent patterns periodically starting from the random reaction center and spreading throughout the entire solution layer was reported. For a batch-stirred system, the bursts of luminescence were found to correlate with the steep decreases of the oscillating Pt electrode potential. These novel results open possibilities for further experimental and theoretical investigations of those spatiotemporal patterns, including studies of the mechanism of this chemically complex process. PMID:17439108

Pekala, Katarzyna; Jurczakowski, Rafa?; Lewera, Adam; Orlik, Marek

2007-04-17

317

Chemical structure of cement aged at normal and elevated temperatures and pressures, Part II: Low permeability class G oilwell cement  

SciTech Connect

Recently, Low Permeability Cement formulation has been developed for oilwell cementing. Therefore, it is important to understand the physical and chemical processes causing cement degradation in the downhole environment. In this study, we have characterised a Low Permeability Class G oilwell Cement immersed for one year in brine at T = 293 K, p = 10{sup 5} Pa and T = 353 K, p = 7 x 10{sup 6} Pa using {sup 29}Si, {sup 27}Al NMR and XRD techniques. Elevated temperature and pressure conditions increase the rate of the pozzolanic reaction and have significant effects on the polymerisation of C-S-H and on the incorporation of Al in the C-S-H structure. Leaching resulted in the formation of calcite and a more polymerised C-S-H with the appearance of tobermorite in the sample cured at elevated temperature and pressure.

Le Saout, Gwenn [Institut Francais du Petrole, 1-4 av de Bois Preau, 92852 Rueil-Malmaison (France) and Laboratoire de Physique et Mecanique des Milieux Heterogenes UMR CNRS 7636, Ecole Superieure de Physique et Chimie Industrielles, 10 rue Vauquelin, 75231 Paris Cedex 05 (France)]. E-mail: gwenn.lesaout@epfl.ch; Lecolier, Eric [Institut Francais du Petrole, 1-4 av de Bois Preau, 92852 Rueil-Malmaison (France); Rivereau, Alain [Institut Francais du Petrole, 1-4 av de Bois Preau, 92852 Rueil-Malmaison (France); Zanni, Helene [Laboratoire de Physique et Mecanique des Milieux Heterogenes UMR CNRS 7636, Ecole Superieure de Physique et Chimie Industrielles, 10 rue Vauquelin, 75231 Paris Cedex 05 (France)

2006-03-15

318

Collecting Plants  

NSDL National Science Digital Library

This article, part of Biodiversity Counts, takes a look at collecting plant specimens. The article discusses what tools are needed to collect specimens, how to press and dry specimens and has tips for numbering and labeling specimens.

319

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

320

Chemical and photophysical properties of AuI, AuII, AuIII, and AuI-dimer complexes  

NASA Astrophysics Data System (ADS)

Various AuI, AuII, AuIII, and AuI-dimer complexes were probed using density-functional theory (DFT), specifically the B3PW91 hybrid functional, and relativistic effective core potentials. The research aimed to investigate the photophysical properties of gold complexes, and inspect the factors that influence the geometry and bonding properties of gold compounds. The results illustrate that the geometry of AuI complexes (ground-state singlet) is very sensitive to the electronic nature of the ligands: ?-donors give a two-coordinate, linear shape; however, ?-acceptors yield a three-coordinate, trigonal planar geometry. Doublet AuIIL3 complexes distort to a T-shape coordination geometry, and are thus ground state models of the corresponding AuIL3 triplet excitons. The disproportionation of AuIIL3 to AuIL3 and AuIIIL3 complexes is endothermic for all ligands investigated, suggesting that these complexes, neglected by experimentalists, are interesting subjects for study and may display unique photochemical properties. For dimeric AuI complexes, the optimized triplet exciton shows a Jahn Teller distortion around only one of the gold centers. Furthermore, the Au Au distance is reduced in the dimer excited state versus the ground state, which should yield interesting Stokes’ shifts.

Barakat, Khaldoon; Cundari, Thomas R.

2005-04-01

321

Collections Conservation.  

ERIC Educational Resources Information Center

Collections conservation is an approach to the preservation treatment of books and book-like materials that is conceptualized and organized in terms of large groups of materials. This guide is intended to enable a library to evaluate its current collections conservation activities. The introduction describes collections conservation and gives…

DeCandido, Robert

322

Collections Conservation.  

ERIC Educational Resources Information Center

|Collections conservation is an approach to the preservation treatment of books and book-like materials that is conceptualized and organized in terms of large groups of materials. This guide is intended to enable a library to evaluate its current collections conservation activities. The introduction describes collections conservation and gives…

DeCandido, Robert

323

Investigation of the Efficiencies of Bioaerosol Samplers for Collecting Aerosolized Bacteria Using a Fluorescent Tracer. II: Sampling Efficiency and Half-Life Time  

Microsoft Academic Search

Using uranine as a physical tracer, this study assessed the sampling efficiencies of four bioaerosol samplers (Andersen 6-stage impactor, all glass impinger “AGI-30,” OMNI-3000, and Airport MD8 with gelatin filter) for collecting Gram-positive bacteria (Enterococcus faecalis), Gram-negative bacteria (Escherichia coli and Campylobacter jejuni), and bacteria without cell wall (Mycoplasma synoviae) which were aerosolized in a HEPA isolator. In addition, the

Yang Zhao; Andre J. A. Aarnink; Piet Doornenbal; Thuy T. T. Huynh; Peter W. G. Groot Koerkamp; Wil J. M. Landman; Mart C. M. de Jong

2011-01-01

324

Effect of bamboo vinegar on regulation of germination and radicle growth of seed plants II: composition of moso bamboo vinegar at different collection temperature and its effects  

Microsoft Academic Search

Moso bamboo vinegar was treated with extractive and separation methods. The acidic, neutral, and phenolic fractions separated from ether-extracted vinegar were analyzed by gas chromatography and gas chromatography-mass spectrometry to identify the major components in moso bamboo vinegar. The compositions of eight moso vinegar fractions collected over different temperature ranges from 100°C to 480°C were also analyzed and their effects

Jun Mu; Tohru Uehara; Takeshi Furuno

2004-01-01

325

Solvent Refined Coal (SRC) process. Selected physical, chemical, and thermodynamic properties of narrow boiling range coal liquids for the SRC-II process. Interim report, March 1980February 1981  

Microsoft Academic Search

Physical, chemical, and thermodynamic properties of coal liquids as a function of boiling range via the pseudocomponent approach are needed for process design now that various direct coal liquefaction processes are being scaled to semi-commercial size. Products from the SRC-II processing of a high volatile bituminous coal were distilled into narrow boiling fractions with average boiling points ranging up to

Gray

1981-01-01

326

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

327

Top Value-Added Chemicals from Biomass - Volume II—Results of Screening for Potential Candidates from Biorefinery Lignin  

SciTech Connect

This report evaluates lignin’s role as a renewable raw material resource. Opportunities that arise from utilizing lignin fit into one of three categories: 1)power, fuel and syngas (generally near-term opportunities) 2) macromolecules (generally medium-term opportunities) 3) aromatics and miscellaneous monomers (long-term opportunities). Biorefineries will receive and process massive amounts of lignin. For this reason, how lignin can be best used to support the economic health of the biorefinery must be defined. An approach that only considers process heat would be shortsighted. Higher value products present economic opportunities and the potential to significantly increase the amount of liquid transportation fuel available from biomass. In this analysis a list of potential uses of lignin was compiled and sorted into “product types” which are broad classifications (listed above as power—fuel—syngas; macromolecules; and aromatics). In the first “product type” (power—fuel—gasification) lignin is used purely as a carbon source and aggressive means are employed to break down its polymeric structure. In the second “product type” (macromolecules) the opposite extreme is considered and advantage of the macromolecular structure imparted by nature is retained in high-molecular weight applications. The third “product type” (aromatics) lies somewhere between the two extremes and employs technologies that would break up lignin’s macromolecular structure but maintain the aromatic nature of the building block molecules. The individual opportunities were evaluated based on their technical difficulty, market, market risk, building block utility, and whether a pure material or a mixture would be produced. Unlike the “Sugars Top 10” report it was difficult to identify the ten best opportunities, however, the potential opportunities fell nicely into near-, medium- and long-term opportunities. Furthermore, the near-, medium- and long-term opportunities roughly align with the three “product types.” From this analysis a list of technical barriers was developed which can be used to identify research needs. Lignin presents many challenges for use in the biorefinery. Chemically it differs from sugars having a complex aromatic substructure. Unlike cellulose, which has a relatively simple substructure of glucose subunits, lignin has a high degree of variability in its structure which differs both from biomass source and from the recovery process used. In addition to its variability lignin is also reactive and to some degree less stable thermally and oxidatively to other biomass streams. What this means is that integrating a lignin process stream within the biorefinery will require identifying the best method to separate lignin from biomass cost-effectively.

Holladay, John E.; White, James F.; Bozell, Joseph J.; Johnson, David

2007-10-01

328

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

329

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

330

New on-line NMR/ON nuclear magnetic dipole moments near 132Sn: II variation with proton and neutron number: shell model treatment of `collective' effects  

NASA Astrophysics Data System (ADS)

Recent on-line nuclear orientation measurements of odd-A nuclear magnetic dipole moments of odd-A Sb, Te and I isotopes by the method of NMR on oriented nuclei mean that we now have complete series of odd-A moments up to, and including, those closest to the double shell closure at 132Sn. In this paper we consider the systematic changes in the measured moments as a function of proton number for the isotonic sequence 133Sb [g7/2+]1 139La [g7/2+]7 and as a function of neutron number for the isotopic sequences 125-133Sb and 127-135I and their interpretation using collective and shell model approaches.

White, G. N.; Stone, N. J.; Rikovska, J.; Ohya, S.; Giles, T. J.; Towner, I. S.; Brown, B. A.; Fogelberg, B.; Jacobsson, L.; Hjorth-Jensen, M.

1999-09-01

331

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

332

The effect of chemical information on the spatial distribution of fruit flies: II Parameterization, calibration, and sensitivity.  

PubMed

In a companion paper (Lof et al., in Bull. Math. Biol., 2008), we describe a spatio-temporal model for insect behavior. This model includes chemical information for finding resources and conspecifics. As a model species, we used Drosophila melanogaster, because its behavior is documented comparatively well. We divide a population of Drosophila into three states: moving, searching, and settled. Our model describes the number of flies in each state, together with the concentrations of food odor and aggregation pheromone, in time and in two spatial dimensions. Thus, the model consists of 5 spatio-temporal dependent variables, together with their constituting relations. Although we tried to use the simplest submodels for the separate variables, the parameterization of the spatial model turned out to be quite difficult, even for this well-studied species. In the first part of this paper, we discuss the relevant results from the literature, and their possible implications for the parameterization of our model. Here, we focus on three essential aspects of modeling insect behavior. First, there is the fundamental discrepancy between the (lumped) measured behavioral properties (i.e., fruit fly displacements) and the (detailed) properties of the underlying mechanisms (i.e., dispersivity, sensory perception, and state transition) that are adopted as explanation. Detailed quantitative studies on insect behavior when reacting to infochemicals are scarce. Some information on dispersal can be used, but quantitative data on the transition between the three states could not be found. Second, a dose-response relation as used in human perception research is not available for the response of the insects to infochemicals; the behavioral response relations are known mostly in a qualitative manner, and the quantitative information that is available does not depend on infochemical concentration. We show how a commonly used Michaelis-Menten type dose-response relation (incorporating a saturation effect) can be adapted to the use of two different but interrelated stimuli (food odors and aggregation pheromone). Although we use all available information for its parameterization, this model is still overparameterized. Third, the spatio-temporal dispersion of infochemicals is hard to model: Modeling turbulent dispersal on a length scale of 10 m is notoriously difficult. Moreover, we have to reduce this inherently three-dimensional physical process to two dimensions in order to fit in the two-dimensional model for the insects. We investigate the consequences of this dimension reduction, and we demonstrate that it seriously affects the parameterization of the model for the infochemicals. In the second part of this paper, we present the results of a sensitivity analysis. This sensitivity analysis can be used in two manners: firstly, it tells us how general the simulation results are if variations in the parameters are allowed, and secondly, we can use it to infer which parameters need more precise quantification than is available now. It turns out that the short term outcome of our model is most sensitive to the food odor production rate and the fruit fly dispersivity. For the other parameters, the model is quite robust. The dependence of the model outcome with respect to the qualitative model choices cannot be investigated with a parameter sensitivity analysis. We conclude by suggesting some experimental setups that may contribute to answering this question. PMID:18780000

de Gee, Maarten; Lof, Marjolein E; Hemerik, Lia

2008-09-09

333

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

334

Collecting Rocks.  

ERIC Educational Resources Information Center

One of a series of general interest publications on science topics, the booklet provides those interested in rock collecting with a nontechnical introduction to the subject. Following a section examining the nature and formation of igneous, sedimentary, and metamorphic rocks, the booklet gives suggestions for starting a rock collection and using…

Barker, Rachel M.

335

Counting Collections  

ERIC Educational Resources Information Center

|This article explores how counting collections of objects helps elementary-age children develop number sense and number relations. The authors provide evidence that counting collections offers multiple entry points for children at different places on the counting trajectory. It is suggested that the teacher's role is one of noticing, questioning,…

Schwerdtfeger, Julie Kern; Chan, Angela

2007-01-01

336

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

2013-04-18

337

Persistent accumulation of calcium/calmodulin-dependent protein kinase II in dendritic spines after induction of NMDA receptor-dependent chemical long-term potentiation.  

PubMed

Calcium/calmodulin-dependent protein kinase II (CaMKII) is a leading candidate for a synaptic memory molecule because it is persistently activated after long-term potentiation (LTP) induction and because mutations that block this persistent activity prevent LTP and learning. Previous work showed that synaptic stimulation causes a rapidly reversible translocation of CaMKII to the synaptic region. We have now measured green fluorescent protein (GFP)-CaMKIIalpha translocation into synaptic spines during NMDA receptor-dependent chemical LTP (cLTP) and find that under these conditions, translocation is persistent. Using red fluorescent protein as a cell morphology marker, we found that there are two components of the persistent accumulation. cLTP produces a persistent increase in spine volume, and some of the increase in GFP-CaMKIIalpha is secondary to this volume change. In addition, cLTP results in a dramatic increase in the bound fraction of GFP-CaMKIIalpha in spines. To further study the bound pool, immunogold electron microscopy was used to measure CaMKIIalpha in the postsynaptic density (PSD), an important regulator of synaptic function. cLTP produced a persistent increase in the PSD-associated pool of CaMKIIalpha. These results are consistent with the hypothesis that CaMKIIalpha accumulation at synapses is a memory trace of past synaptic activity. PMID:15496668

Otmakhov, Nikolai; Tao-Cheng, Jung-Hwa; Carpenter, Stephen; Asrican, Brent; Dosemeci, Ayse; Reese, Thomas S; Lisman, John

2004-10-20

338

Collection and chemical derivatization of airborne phosgene with 1-(2-pyridyl)-piperazine and determination by high performance liquid chromatography  

SciTech Connect

As an alternative to currently available measurement methods, Chromosorb coated with 1-(2-pyridyl)-piperazine (PYP) was evaluated for collection/derivatization of phosgene gas. Solid sorbent tubes contained 100 mg of 2.5% PYP coated on Chromosorb. Phosgene reacts with two equivalents of PYP to form a substituted urea derivative which is desorbed with acetonitrile and determined by reversed phase high performance liquid chromatography with ultraviolet absorbance detection. In comparison to the 4,4[prime]-nitrobenzyl pyridine in diethylphthalate colorimetric technique, the recovery of phosgene from the sorbent tube was quantitative from 0.02 to 1 ppm phosgene and was unaffected by humidity. The limit of detection for a 20 L air sample was estimated to be 0.005 ppm. The utility of the method was further improved by demonstrating the use of triphosgene (bis-(trichloromethyl)-carbonate) in the synthesis of the urea derivative used for standardization, thus eliminating the need for working with gaseous phosgene in preparing analytical standards.

Rando, R.J.; Poovey, H.G. (Tulane Univ. Medical Center, New Orleans, LA (United States). Section of Bioenvironmental Research); Chang, Shau-nong (Tulane Univ. Medical Center, New Orleans, LA (United States). Dept. of Environmental Health Sciences)

1993-01-01

339

Synthesis, structural elucidation, electro-chemical behaviour and fungitoxic activity of transition metal(II) mixed-ligand complexes with some Schiff bases  

Microsoft Academic Search

The Schiff bases, potassium salt of salicylidene-?-alanine [KHL], bis(benzylidene)ethylenediamine [SB] and thiophene-o-carboxaldene-p-toluidine [SB], and mixed-ligand complexes with Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) have been prepared. They were characterized by elemental analyses, magnetic susceptibility measurements, thermogravimetric analyses (t.g.a.), infrared spectra and electronic spectra. The mixed-ligand complexes were found to have the general composition [M(L)(SB)(H2O)]. All the mixed-ligand complexes were

Hitesh M. Parekh; Mohan N. Patel

2005-01-01

340

75 FR 8996 - Notice of Information Collection  

Federal Register 2010, 2011, 2012, 2013

...products or 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

341

75 FR 63205 - Notice of Information Collection.  

Federal Register 2010, 2011, 2012, 2013

...recertification of eligibility of compliance with SBIR/ STTR program requirements. II. Method of Collection The SBIR/STTR contractor may submit the required...collected electronically. III. Data Title: SBIR/STTR Contractor Recertification....

2010-10-14

342

Application of a high surface area solid-phase microextraction air sampling device: collection and analysis of chemical warfare agent surrogate and degradation compounds.  

PubMed

This work examines a recently improved, dynamic air sampling technique, high surface area solid-phase microextraction (HSA-SPME), developed for time-critical, high-volume sampling and analysis scenarios. The previously reported HSA-SPME sampling device, which provides 10-fold greater surface area compared to commercially available SPME fibers, allowed for an increased analyte uptake per unit time relative to exhaustive sampling through a standard sorbent tube. This sampling device has been improved with the addition of a type-K thermocouple and a custom heater control circuit for direct heating, providing precise (relative standard deviation ?1%) temperature control of the desorption process for trapped analytes. Power requirements for the HSA-SPME desorption process were 30-fold lower than those for conventional sorbent-bed-based desorption devices, an important quality for a device that could be used for field analysis. Comparisons of the HSA-SPME device when using fixed sampling times for the chemical warfare agent (CWA) surrogate compound, diisopropyl methylphosphonate (DIMP), demonstrated that the HSA-SPME device yielded a greater chromatographic response (up to 50%) relative to a sorbent-bed method. Another HSA-SPME air sampling approach, in which two devices are joined in tandem, was also evaluated for very rapid, low-level, and representative analysis when using discrete sampling times for the compounds of interest. The results indicated that subparts per billion by volume concentration levels of DIMP were detectable with short sampling times (?15 s). Finally, the tandem HSA-SPME device was employed for the headspace sampling of a CWA degradation compound, 2-(diisopropylaminoethyl) ethyl sulfide, present on cloth material, which demonstrated the capability to detect trace amounts of a CWA degradation product that is estimated to be less volatile than sarin. The rapid and highly sensitive detection features of this device may be beneficial in decision making for law enforcement, military, and civilian emergency organizations and responders, providing critical information in a contaminated environment scenario when time is of the essence. PMID:23902152

Stevens, Michael E; Tipple, Christopher A; Smith, Philip A; Cho, David S; Mustacich, Robert V; Eckenrode, Brian A

2013-08-29

343

Collected Reprints.  

National Technical Information Service (NTIS)

The report contains a collection of reprints from ESSA Institute of Oceanography, Atlantic and Pacific Oceanographic laboratories, that includes meteorological oceanography, geological oceanography, physical oceanography as well as general reports in ocea...

1966-01-01

344

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

345

Chemical Reactions (Netorials)  

NSDL National Science Digital Library

Chemical Reactions: this is a resource in the collection "Netorials". The Netorials cover selected topics in first-year chemistry including: Chemical Reactions, Stoichiometry, Thermodynamics, Intermolecular Forces, Acids & Bases, Biomolecules, and Electrochemistry.

346

Chemical warfare agents  

Microsoft Academic Search

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

S. Chauhan; R. D’Cruz; S. Faruqi; K. K. Singh; S. Varma; M. Singh; V. Karthik

2008-01-01

347

Possible Bose-condensate behavior in a quantum phase originating in a collective excitation in the chemically and optically doped Mott-Hubbard system UO2+x  

NASA Astrophysics Data System (ADS)

X-ray pair distribution function (pdf) and U L3 extended x-ray absorption fine structure (EXAFS) and neutron pdf measurements that give identical results for UO2 show U(VI)-oxo moieties with x rays for mixed valence U4O9 and U3O7, in contrast to the neutron data that indicate only U(V) sites with no short U-O bonds as well as other differences. In addition, although the EXAFS spectra of UO2 are essentially identical at 30, 100, and 200 K, those of the UO2+x compounds exhibit different nearest-neighbor U-O distributions at each temperature. Further tunneling polaron-type behavior is found in the broadening of the features of the O K-edge x-ray absorption spectra (XAS) of the UO2+x compounds. Raman spectra of powders also show a large increase in scattering cross section with increasing O content that would originate in a change in the electronic structure that increases the overall polarizability. The XAS and Raman also show that U4O9 does not behave as a linear combination of the UO2 and U3O7 fluorite endpoints. The properties induced by mobile rather than static charged quasiparticles were explored by optical pumping of the metal-to-metal charge-transfer transition. The temperature dependence of 4.71 eV pump-1.57 eV probe reflectivity on UO2 that initially populates the U 6d-dominated portion of the upper Hubbard band (UHB) shows a sharp 28-?sec lifetime peak at 25 K that may be associated with the fluctuations of its antiferromagnetic transition. Pumping at 3.14 eV into the 5f-dominated portion of the UHB shows an analogous 2.8-?sec peak but also a plateau bracketing this peak that ends in a cusp at 50-60 K and an abrupt change in the hardening rate of a novel 12-15 GHz phonon that is the signature for the quasiparticle quantum phase. The different results for the different excitation channels indicate a highly specific nonthermal relaxation mechanism. These results constitute the first observation of a distinct phase of photoinduced quasiparticles that is sufficiently coupled to the lattice to undergo a gap-opening transition. When the intragap state is probed with a terahertz time domain spectroscopy (TTDS) measurement 33 psec after a 3.14 excitation pulse, it shows increased absorption in the 0.5-1.1 THz range with a decrease in temperature from ˜30 to 10 K instead of the expected decrease, a result consistent with the presence of a condensate. These results are too extreme to originate in the dynamical, nonadiabatic, coupled charge-transfer-phonon/tunneling polaron scenario previously used for doped Mott-Hubbard insulators with intermediate electron-phonon coupling and therefore indicate novel physics. One possibility that could cause all of these behaviors is that a collective, dynamical, charge transfer-coupled Peierls distortion involving the 2 U(V) ? U(IV)+U(VI)-oxo excitation occurs coherently over an entire domain to cause the atoms in this domain to condense into a system with Bose-Einstein or Bose-Einstein-Hubbard properties.

Conradson, Steven D.; Durakiewicz, Tomasz; Espinosa-Faller, Francisco J.; An, Yong Q.; Andersson, David A.; Bishop, Alan R.; Boland, Kevin S.; Bradley, Joseph A.; Byler, Darrin D.; Clark, David L.; Conradson, Dylan R.; Conradson, Leilani L.; Costello, Alison L.; Hess, Nancy J.; Lander, Gerard H.; Llobet, Anna; Martucci, Mary B.; Mustre de Leon, Jose; Nordlund, Dennis; Lezama-Pacheco, Juan S.; Proffen, Thomas E.; Rodriguez, George; Schwarz, Daniel E.; Seidler, Gerald T.; Taylor, Antoinette J.; Trugman, Stuart A.; Tyson, Trevor A.; Valdez, James A.

2013-09-01

348

Pioneer game in collective actions: Experimental evidence  

Microsoft Academic Search

Collective actions are typical social and economic behavior, in which free riders exist objectively. Successful execution of collective actions is related to pioneer game, the value expectation and the follow-up sequence of followers. Through localized experiments, this paper verifies that: (i) collective actions are realizable, (ii) free riders can be weakened or relieved, and (iii) the realization probability of collective

Yichuan Wang

2011-01-01

349

I. Probing polymer adsorption using an emissive semiconductor substrate. II. Correlation of chemical structure and swelling behavior in N-alkylcrylamide hydrogels  

NASA Astrophysics Data System (ADS)

Semiconductor photoluminescence (PL) is a highly surface-sensitive technique that has allowed characterization of a wide variety of semiconductor-adsorbate interactions. This surface sensitivity can be rationalized through an understanding of the mechanisms by which adsorbate interactions can perturb the electronic structure of semiconductors, leading to observable changes in PL intensity. Using this approach, quenching of the photoluminescence (PL) intensity of single-crystal CdSe by adsorption of poly(acrylic acid) (PAA) from methanol solutions is introduced in Part I as a sensitive probe of polymer interactions with a semiconductor surface. Comparison with the influence on CdSe PL of methanol solutions of acrylic acid (AA), propionic acid (PrA), methyl acrylate (MA), along with IR data, indicate that surface binding leading to PL quenching involves the carboxylic acid proton. Over the range of PAA molecular weights studied in methanol (Mw ˜2K to 100K), the dependence of PL quenching on concentration is found to be insensitive to PAA chain length and markedly different from that of a surface COOH-derivatived dendrimer (PAMAM-COOH), suggesting that PAA uncoils upon adsorption onto the CdSe surface. The time-dependence of the PL decay indicates diffusion-controlled adsorption kinetics for the PAA/methanol system. Implications of the use of this methodology for characterizing semiconductor-polymer interfaces are discussed. Based on this understanding of the PAA/CdSe interface, molecularly imprinted PAA-film-coated CdSe surfaces are described as a strategy for selective chemical sensing. In this way, selective detection of ammonia from a mixture of trimethylamine and ammonia is achieved. Part II focuses on the swelling properties of hydrogels, which exhibit up to 1000-fold changes in volume in response to various stimuli. The thermoshrinking properties for the series of N-alkylacrylamide hydrogels (alkyl = methyl, ethyl, isopropyl, and n-propyl), are investigated in order to study the effect of the chemical structure of the alkyl substituent on the gel swelling behavior as a function of temperature. Generally, larger alkyl chains produced dramatic decreases in gel transition temperature, as well as influenced the nature of thermoshrinking. Additionally, a quantitative correlation was found between the gel transition temperatures and the water/octanol partition coefficients for appropriately chosen small molecule model compounds.

Seker, Fazila

350

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

2013-03-04

351

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

352

Oz Collection  

NSDL National Science Digital Library

The world of Oz is a big place, and this particular digital collection from the University of Minnesota pays homage to some of its many characters, stories, and more. The materials here were collected by Laura Jane Musser, and they include annual meeting program notes from the International Wizard of Oz club, sheet music from Oz-related productions, catalogs, and coloring books. The digitized materials also include a number of famous books from the Oz series, such as "The Marvelous Land of Oz" and "The Land of Oz". Visitors can use a finding aid to make their way through the materials, and if they are interested in doing research with these materials they can learn more about making a visit to the collections.

353

Preparation of an ion-selective electrode by chemical treatment of copper wire for the measurement of copper(II) and iodide by batch and flow-injection potentiometry  

Microsoft Academic Search

The preparation of an ion-selective electrode by chemical treatment of copper wire and its application for the measurements\\u000a of copper (II) and iodide ions is described. The proposed reaction mechanism at the sensing surface, which explains the response\\u000a of the electrode to Cu2+ and iodide ions, is discussed. The prepared electrode was suitable for direct potentiometric measurements of iodide and

D. Dob?nik; M. Kolar; J. Komljenovi?; Nj. Radi?

1999-01-01

354

Formation of ((CN)âRu\\/sup II\\/-CN-Ru\\/sup III\\/(CN)â)\\/sup 6 -\\/ by chemical oxidation, electrochemical oxidation, and photooxidation of Ru(CN)â\\/sup 4 -  

Microsoft Academic Search

Electron transfer to a ligand field excited state of tris(glycinato)cobalt(III) by hexacyanoruthenium(II) was observed in pH 5 acetate-buffered aqueous solution. A product of the reaction is a species that has an intervalence transfer band at 9.1 x 10³ cm⁻¹ (1094 nm) with a molar absorptivity of about 7 x 10³ M⁻¹ cm⁻¹. The same spectroscopic band results from chemical oxidation

K. Z. Ismail; M. S. Tunuli; S. G. Weber

1987-01-01

355

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

356

Diabetes Collection.  

National Technical Information Service (NTIS)

This is a collection of fact sheets and reports dealing with information on diabetes. Diabetes is a disease in which the body does not produce or properly use insulin. Insulin is a hormone that is needed to convert sugar, starches and other food into ener...

2005-01-01

357

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

Microsoft Academic Search

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

M. V. Cone; R. A. Faust; M. F. Baldauf

1982-01-01

358

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

359

Digitial Collections: Boston College  

NSDL National Science Digital Library

John J. Burns Library, Rare Books and Special Collections at Boston College, offers some of its collections on the Web. The largest is the Liturgy and Life Collection, approximately 1,200 artifacts selected from perhaps the "most comprehensive archive in America on the pre-Vatican II Catholic Church." Also available are Boston Gas Company photos, about 400 images from the 1880s to the 1970s, documenting both the company and the city of Boston, and Thomas P. O'Neill Photographs, primarily from O'Neill's years as Speaker of the US House of Representatives. All of the databases allow browsing as well as searching, very helpful for users who do not know if Saint Christopher is entered as St. or Saint. Unlike other religious history collections, many of the pictures in Liturgy & Life are images of objects that people owned and carried in their pockets, such as the nineteen Saint Christopher medals that I located with the browse function. Be sure to check out the Gas Company collection's fascinating views of pre-1900 Boston, including over 200 cyanotypes that reproduce beautifully on the Web.

360

Structure of the oxygen-evolving complex of photosystem II: information on the S(2) state through quantum chemical calculation of its magnetic properties.  

PubMed

Twelve structural models for the S(2) state of the oxygen-evolving complex (OEC) of photosystem II are evaluated in terms of their magnetic properties. The set includes ten models based on the 'fused twist' core topology derived by polarized EXAFS spectra and two related models proposed in recent mechanistic investigations. Optimized geometries and spin population analyses suggest that Mn(iii), which is most often identified with the manganese ion at site D, is always associated with a penta-coordinate environment, unless a chloride is directly ligated to the metal. Exchange coupling constants were determined by broken-symmetry density functional theory calculations and the complete spectrum of magnetic sublevels was obtained by direct diagonalization of the Heisenberg Hamiltonian. Seven models display a doublet ground state and are considered spectroscopic models for the ground state corresponding to the multiline signal (MLS) of the S(2) state of the OEC, whereas the remaining five models display a sextet ground state and could be related to the g = 4.1 signal of the S(2) state. It is found that the sign of the exchange coupling constant between the Mn centres at positions A and B of the cluster is directly related to the ground state multiplicity, implying that interconversion between the doublet and sextet can be induced by only small structural perturbations. The recently proposed quantum chemical method for the calculation of (55)Mn hyperfine coupling constants is subsequently applied to the S(2) MLS state models and the quantities that enter into the individual steps of the procedure (site-spin expectation values, intrinsic site isotropic hyperfine parameters and projected (55)Mn isotropic hyperfine constants) are analyzed and discussed in detail with respect to the structural and electronic features of each model. The current approach performs promisingly. It reacts sensitively to structural distortions and hence may be able to distinguish between different structural proposals. Thus it emerges as a useful contributor to the ongoing efforts that aim at establishing correlations between the body of spectroscopic data available for the various S(i) states of the OEC and their actual geometric features. PMID:19639153

Pantazis, Dimitrios A; Orio, Maylis; Petrenko, Taras; Zein, Samir; Lubitz, Wolfgang; Messinger, Johannes; Neese, Frank

2009-06-23

361

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.

362

Xenobiotic metabolism capacities of human skin in comparison with a 3D-epidermis model and keratinocyte-based cell culture as in vitro alternatives for chemical testing: phase II enzymes.  

PubMed

The 7th Amendment to the EU Cosmetics Directive prohibits the use of animals in cosmetic testing for certain endpoints, such as genotoxicity. Therefore, skin in vitro models have to replace chemical testing in vivo. However, the metabolic competence neither of human skin nor of alternative in vitro models has so far been fully characterized, although skin is the first-pass organ for accidentally or purposely (cosmetics and pharmaceuticals) applied chemicals. Thus, there is an urgent need to understand the xenobiotic-metabolizing capacities of human skin and to compare these activities to models developed to replace animal testing. We have measured the activity of the phase II enzymes glutathione S-transferase, UDP-glucuronosyltransferase and N-acetyltransferase in ex vivo human skin, the 3D epidermal model EpiDerm 200 (EPI-200), immortalized keratinocyte-based cell lines (HaCaT and NCTC 2544) and primary normal human epidermal keratinocytes. We show that all three phase II enzymes are present and highly active in skin as compared to phase I. Human skin, therefore, represents a more detoxifying than activating organ. This work systematically compares the activities of three important phase II enzymes in four different in vitro models directly to human skin. We conclude from our studies that 3D epidermal models, like the EPI-200 employed here, are superior over monolayer cultures in mimicking human skin xenobiotic metabolism and thus better suited for dermatotoxicity testing. PMID:22509834

Götz, Christine; Pfeiffer, Roland; Tigges, Julia; Ruwiedel, Karsten; Hübenthal, Ulrike; Merk, Hans F; Krutmann, Jean; Edwards, Robert J; Abel, Josef; Pease, Camilla; Goebel, Carsten; Hewitt, Nicola; Fritsche, Ellen

2012-05-01

363

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.

364

Random chemical mutagenesis of a specific psbDI region coding for a lumenal loop of the D2 protein of photosystem II in Synechocystis sp. PCC 6803  

Microsoft Academic Search

To identify amino acid residues of the D2 protein that are critical for functional photosystem II (PS II), sodium bisulfite was utilized for in vitro random mutagenesis of the psbDI gene from Synechocystis sp. PCC 6803. Sodium bisulfite reacts specifically with cytosine in single-stranded regions of DNA and does not attack double-stranded DNA. Using a hybrid plasmid that was single-stranded

Svetlana Ermakova-Gerdes; Sergey Shestakov; Wim Vermaas

1996-01-01

365

Formation of ((CN)/sub 5/Ru/sup II/-CN-Ru/sup III/(CN)/sub 5/)/sup 6 -/ by chemical oxidation, electrochemical oxidation, and photooxidation of Ru(CN)/sub 6//sup 4 -/  

SciTech Connect

Electron transfer to a ligand field excited state of tris(glycinato)cobalt(III) by hexacyanoruthenium(II) was observed in pH 5 acetate-buffered aqueous solution. A product of the reaction is a species that has an intervalence transfer band at 9.1 x 10/sup 3/ cm/sup -1/ (1094 nm) with a molar absorptivity of about 7 x 10/sup 3/ M/sup -1/ cm/sup -1/. The same spectroscopic band results from chemical oxidation (H/sub 2/O/sub 2/, Ce/sup 4 +/), anodic oxidation (Pt electrode), and excited-state electron transfer to tris(2,2'-bipyridine) ruthenium(II). Steady-state analysis of the kinetics of the reaction leads to an estimation of the lifetime of the excited state of tris(glycinato)cobalt(III) as 23 +/- 4 ns. The most likely species responsible for the infrared band is the cyanide-bridged dimer ((CN)/sub 5/Ru/sup II/-CN-Ru/sup III/(CN)/sub 5/)/sup 6 -/. The kinetics of its formation from hexacyanoruthenium(II) and -(III) are rapid (second-order rate constant approx. 1 x 10/sup 4/ M/sup -1/ s/sup -1/) in contrast to recent observations on nonphotochemical reactions of hexacyanoruthenium(III).

Ismail, K.Z.; Tunuli, M.S.; Weber, S.G.

1987-05-20

366

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.

367

Synthesis, antitumor activity, and chemical properties of silaplatin and related platinum (II) and platinum (IV) complexes derived from beta-silyl amines.  

PubMed

Platinum (II) and platinum (IV) coordination complexes derived from beta-silyl-substituted amines were prepared. The solubility of selected complexes in water and physiological saline was measured, and the effect of the beta-silicon on the reactivity of the complex in aqueous solution was determined by HPLC. The stabilities of selected silyl complexes were compared to the carbon analogues. The cyclic complexes 2a ("silaplatin") and its Pt(IV) analogue, 2b, were very active against L1210 leukemia in vivo. Both the platinum (II) complex 2a and the platinum (IV) complex 2b produced a significant number of cures over the dose range 10-40 mg/kg. The platinum (II) complex 2a, silaplatin, was very active in vivo against an L1210 leukemia subline that was resistant to cisplatin; 2a was also active, when given ip, against ic implanted L1210. The cyclobutanedicarboxylic acid complex 3c was synthesized; this complex was active against both cisplatin sensitive and resistant L1210 leukemia but was less potent than the analogous dichloro compound 2a. The acyclic platinum (II) and platinum (IV) complexes 1a,b were synthesized and unexpectedly found to be inactive in vivo against L1210 leukemia. More lipophilic silaplatin analogues were prepared--Pt(II) complex 2c and Pt(IV) complex 2d have one additional methylene carbon compared to 2a,b, whereas Pt(II) complex 2e and Pt(IV) complex 2f have two additional methylene carbons. Cyclization of the alkyl groups attached to the silicon gave the spiro bicyclic Pt(II) complexes 10a and 11a and the Pt(IV) complexes 10b and 11b. PMID:7562909

Anderson, W K; Kasliwal, R; Houston, D M; Wang, Y S; Narayanan, V L; Haugwitz, R D; Plowman, J

1995-09-15

368

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

2013-06-13

369

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

370

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

371

Double Potential Step Chronocoulometry. II. Measurement of the Chemical Reaction Rate in an EC Mechanism when Both Electrode Reactant and Product are Adsorbed.  

National Technical Information Service (NTIS)

The double potential step chronocoulometric theory for EC-type electrode reactions (irreversible chemical kinetics) both with and without complications arising from the adsorption of electrode reactant and product has been verified using the reduction of ...

C. N. Reilley R. P. Van Duyne T. H. Ridgway

1971-01-01

372

Adsorption performance of Al-pillared bentonite clay for the removal of cobalt(II) from aqueous phase  

Microsoft Academic Search

In this research, the natural bentonite clay collected from Ashapura Clay Mines, Gujarat State, India, was utilized as a precursor to produce aluminium-pillared bentonite clay (Al-PILC) for the removal of cobalt(II) [Co(II)] ions from aqueous solutions. The original bentonite clay and Al-PILC were characterized with the help of chemical analyses, methylene blue (MB) adsorption isotherm, powder X-ray diffraction (XRD), scanning

D. M. Manohar; B. F. Noeline; T. S. Anirudhan

2006-01-01

373

Effect of mining chemicals on biosorption of Cu(II) by the non-living biomass of the macrophyte Potamogeton lucens  

Microsoft Academic Search

The present work investigates the effect of some compounds commonly discharged from mineral processing plants on biosorption of heavy metals by the non-living biomass of the freshwater macrophyte Potamogeton lucens. Studies of sorption of Cu (II) in the presence of metal ions, surfactants, EDTA and cyanide were carried out at laboratory scale. The results show that copper adsorption by ion

I. A. H. Schneider; R. W. Smith; J. Rubio

1999-01-01

374

Engineering a chemical implementation device and an imaging device for detecting chemiluminescence with a Polaroid high-speed detector film: application to influenza diagnostics with the ZstatFlu-II test.  

PubMed

We describe the engineering and product development of the chemiluminescent ZstatFlu-II Test kit for influenza diagnostics. The reaction vessel is a chemical implementation device with a polystyrene bottom chamber and a polypropylene top chamber that screw together. The patient's specimen is dispersed in a proprietary diluent and mixed inside the bottom chamber with the influenza viral neuraminidase-specific substrate, 1,2-dioxetane-4,7-dimethoxy-Neu5Ac. Neuraminidase catalysis releases the dioxetane. The top chamber contains 40% NaOH and is sealed at the top with an ABS plastic plug-crush pin assembly. The top chamber floor is 85% thinner at the centre, forming a frangible flap. An automated imaging device serves as an incubator for the chemical implementation devices and also facilitates the piercing of the flap by the crush pin. This action results in NaOH flushing into the bottom chamber, initiating chemiluminescence. The imaging device also exposes the Polaroid high-speed detector film to chemiluminescence. At the end of exposure, the film is automatically processed and ejected. Chemiluminescence from an influenza virus-positive specimen produces a "+"-shaped white image, archiving the diagnostic outcome. The modular ZstatFlu-II test kit components are easily adaptable for the chemiluminescent detection of a wide range of analytes. PMID:12687627

Achyuthan, Komandoor E; Pence, Lisa M; Mantell, Daniel R; Nangeroni, Paul E; Mauchan, Donald M; Aitken, William M; Appleman, James R; Shimasaki, Craig D

375

Gamma II  

NASA Astrophysics Data System (ADS)

GAMMA II is the Guide Star Automatic Measuring MAchine relocated from STScI to the Astronomical Photographic Data Archive (APDA) at the Pisgah Astronomical Research Institute (PARI). GAMMA II is a multi-channel laser-scanning microdensitometer that was used to measure POSS and SERC plates to create the Guide Star Catalog and the Digital Sky Survey. The microdensitometer is designed with submicron accuracy in x and y measurements using a HP 5507 laser interferometer, 15 micron sampling, and the capability to measure plates as large as 0.5-m across. GAMMA II is a vital instrument for the success of digitizing the direct, objective prism, and spectra photographic plate collections in APDA for research. We plan several targeted projects. One is a collaboration with Drs. P.D. Hemenway and R. L. Duncombe who plan to scan 1000 plates of 34 minor planets to identify systematic errors in the Fundamental System of celestial coordinates. Another is a collaboration with Dr. R. Hudec (Astronomical Institute, Academy of Sciences of the Czech Republic) who is working within the Gaia Variability Unit CU7 to digitize objective prism spectra on the Henize plates and Burrell-Schmidt plates located in APDA. These low dispersion spectral plates provide optical counterparts of celestial high-energy sources and cataclysmic variables enabling the simulation of Gaia BP/RP outputs. The astronomical community is invited to explore the more than 140,000 plates from 20 observatories now archived in APDA, and use GAMMA II. The process of relocating GAMMA to APDA, re-commissioning, and starting up the production scan programs will be described. Also, we will present planned research and future upgrades to GAMMA II.

Barker, Thurburn; Castelaz, M.; Cline, J.; Owen, L.; Boehme, J.; Rottler, L.; Whitworth, C.; Clavier, D.

2011-05-01

376

Uranium favorability of tertiary sedimentary rocks of the western Okanogan highlands and of the upper Columbia River valley, Washington. [Measurement and sampling of surface sections, collection of samples from isolated outcrops, and chemical and mineralogical analyses of samples; no known uranium deposits  

Microsoft Academic Search

Tertiary sedimentary rocks in the northern portions of the western Okanogan highlands and in the upper Columbia River valley were investigated during a regional study to determine the favorability for potential uranium resources of the Tertiary sedimentary rocks of northeastern Washington. This project involved measurement and sampling of surface sections, collection of samples from isolated outcrops, and chemical and mineralogical

D. K. Marjaniemi; J. W. Robins

1975-01-01

377

Chemical Reactor Theory Applied to Modeling the Dynamics of a Control System for Water Quality of a River: Phase II. Study of a River System as a Chemical Reactor.  

National Technical Information Service (NTIS)

The report discusses research modelling a river system as a tubular chemical reactor which can purge itself of oxidizable organics if scheduling of pollution inputs from known sources is guided by a feed-forward control scheme which responds to continuous...

E. G. Bobalek

1969-01-01

378

The 5th World Congress of chemical engineering: Technologies critical to a changing World. Volume II: Agriculture, food biotechnology biomedical electric power process safety  

SciTech Connect

Volume 2 of the proceedings from the 5th World Congress of Chemical Engineering covers four major topic areas from which papers were selected for the database: Agriculture, Food; Biotechnology; Electric Power, and Process Safety. Pertinent subtopics include: Renewable Resource Engineering; Special Processes in the Food Industry; Advances in Metabolite Production; Advances in Fermentation and Cell Culture Engineering; Coal and Nuclear Central Station Power Plants; Large Natural Gas Fired Power Stations; Distributed Generation; Potential Impact of Biomass Energy; and Chemical Hazards in Plant Design. 29 papers were selected from Volume 1 for the database.

NONE

1996-12-31

379

A density functional study of the chemical differences between Type I and Type II MoS2-based structures in hydrotreating catalysts.  

PubMed

Density functional theory is used to investigate the origin of the activity differences between Type I and Type II MoS2-based structures in hydrotreating catalysts. It is well known that the Type II structures, where only weak interactions with the support exist, have a higher catalytic activity than Type I structures, where Mo-O linkages to the alumina are present. The present results show that the differences in activities for MoS2 and Co-Mo-S structures can be attributed to the electronic and bonding differences introduced by the bridging O bonds. We find that the Mo-O linkages are most probably located on the (1010) S edge. The presence of oxygen linkages increases the energy required to form sulfur vacancies significantly so that almost no vacancies can be formed at these and neighboring sites. In this way, the reactivity of the S edge is reduced. In addition, the studies also show that the linkages introduce changes in the one-dimensional metallic-like brim states. Furthermore, the presence of oxygen linkages also changes the energetics of hydrogen adsorption, which becomes less exothermic on sulfur sites directly above linkages and more exothermic on sulfur sites adjacent to linkages. The present results explain previously observed differences in Type I-Type II transition temperatures for Co-Mo-S structures with different Co contents. PMID:16851217

Hinnemann, Berit; Nørskov, Jens K; Topsøe, Henrik

2005-02-17

380

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

PubMed

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 of evidence paradigm using rats, mice, and rabbit reprotox study data and are designed to identify trans-species reprotoxicants. The majority of the reprotox QSARs exhibit good predictive performance properties: high specificity (>80%), low false positives (<20%), significant receiver operating characteristic (ROC) values (>2.00), and high coverage (>80%) in 10% leave-many-out validation experiments. The QSARs are based on 627-2023 chemicals and exhibited a wide applicability domain for FDA regulated organic chemicals for which they were designed. Experiments were also performed using the MC4PC multiple module prediction technology, and ROC statistics, and adjustments to the ratio of active to inactive (A/I ratio) chemicals in training data sets were made to optimize the predictive performance of QSAR models. Results revealed that an A/I ratio of approximately 40% was optimal for MC4PC. We discuss specific recommendations for the application of the reprotox QSAR battery. PMID:17175082

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

2006-12-18

381

Measurements of atmospheric parameters during Indian Space Research Organization Geosphere Biosphere Program Land Campaign II at a typical location in the Ganga Basin: 2. Chemical properties  

Microsoft Academic Search

This paper attempts to analyze the chemical compositions of the near surface aerosols at a typical location in the Ganga basin with an emphasis on delineating the source of aerosols in foggy\\/hazy conditions. Collocated measurements of a number of atmospheric and aerosol parameters along with simultaneous sampling of near surface aerosols of size less than 10 ?m (PM10) were made

Vinod Tare; S. N. Tripathi; N. Chinnam; A. K. Srivastava; Sagnik Dey; M. Manar; Vijay P. Kanawade; A. Agarwal; S. Kishore; R. B. Lal; M. Sharma

2006-01-01

382

Studies on chemical modification and biology of a natural product, gambogic acid (II): Synthesis and bioevaluation of gambogellic acid and its derivatives from gambogic acid as antitumor agents  

Microsoft Academic Search

Gambogic acid (GA) has been reported to be a potent apoptosis inducer. The fact that it is amenable to chemical modification makes GA an attractive molecule for the development of anticancer agents. We firstly reported the synthesis of gambogellic acid, which was generated under acid catalysis from readily available GA by a base-catalyzed diene intramolecular annelation. Sequentially, thirteen new compounds

Jinxin Wang; Junhai Ma; Qidong You; Li Zhao; Fan Wang; Chong Li; Qinglong Guo

2010-01-01

383

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

384

The Entropy and Thermodynamic Potentials of Real Gases and Mixtures of Real Gases and a Mass Action Law for Chemical Reaction Between Real Gases: II. Integrated Equations  

Microsoft Academic Search

The general thermodynamic equations derived in the first paper are integrated by means of a new equation of state for gas mixtures. Thus the energy, heat content, entropy and thermodynamic potentials FV,T and Fp,T of a mixture of real gases, and the chemical potential and fugacity of a gas in a mixture are expressed as integrated functions of V, T,

James A. Beattie

1928-01-01

385

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

386

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

387

78 FR 9429 - Agency Information Collection Activities; Proposed Collection; Comments Requested: Application...  

Federal Register 2010, 2011, 2012, 2013

...Procurement Quota for Controlled Substances and Ephedrine, Pseudoephedrine, and Phenylpropanolamine...Procurement Quota for Controlled Substances and Ephedrine, Pseudoephedrine, and Phenylpropanolamine...Schedule I or II or the List I chemicals ephedrine, pseudoephedrine, and...

2013-02-08

388

77 FR 71832 - Agency Information Collection Activities: Proposed Collection; Comments Requested: Application...  

Federal Register 2010, 2011, 2012, 2013

...Procurement Quota for Controlled Substances and Ephedrine, Pseudoephedrine, and Phenylpropanolamine...Procurement Quota for Controlled Substances and Ephedrine, Pseudoephedrine, and Phenylpropanolamine...Schedule I or II or the List I chemicals ephedrine, pseudoephedrine, and...

2012-12-04

389

75 FR 42133 - Agency Information Collection Activities: Proposed Collection; Comments Requested: Application...  

Federal Register 2010, 2011, 2012, 2013

...Procurement Quota for Controlled Substances and Ephedrine, Pseudoephedrine, and Phenylpropanolamine...Procurement Quota for Controlled Substances and Ephedrine, Pseudoephedrine, and Phenylpropanolamine...Schedule I or II or the List I chemicals ephedrine, pseudoephedrine, and...

2010-07-20

390

75 FR 59294 - Agency Information Collection Activities: Proposed Collection; Comments Requested: Application...  

Federal Register 2010, 2011, 2012, 2013

...Procurement Quota for Controlled Substances and Ephedrine, Pseudoephedrine, and Phenylpropanolamine...Procurement Quota for Controlled Substances and Ephedrine, Pseudoephedrine, and Phenylpropanolamine...Schedule I or II or the List I chemicals ephedrine, pseudoephedrine, and...

2010-09-27

391

Combustion mechanism of double-base propellant containing nitrogen heterocyclic nitroamines (II): The temperature distribution of the flame and its chemical structure  

Microsoft Academic Search

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

Qi-Long Yan; Zhen-Wei Song; Xiao-Bing Shi; Zhi-Yuan Yang; Xiao-Hong Zhang

2009-01-01

392

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

393

The influence of the Henry number on the conjugate mass transfer from a sphere: II – mass transfer accompanied by a first-order chemical reaction  

Microsoft Academic Search

Conjugate mass transfer between a sphere and a surrounding fluid flow in the presence of an isothermal, first-order irreversible\\u000a chemical reaction occurring either in the continuous or in the dispersed phase has been analysed. Two sphere models, the sphere\\u000a with rigid interface and the sphere with mobile interface and internal circulation, have been studied. Creeping flow is assumed.\\u000a The mass

Gh. Juncu

2002-01-01

394

Photooxidation-Reduction Sensitized by Copolymers of [2-(9,10Anthraquinonyl) methyl Methacrylate. II. Intramolecular Chemical Quenching by 2-Hydroxyethyl Methacrylate Units  

Microsoft Academic Search

Copolymers of [2-(9,10-anthraquinonyl)] methyl methacrylate (AQMMA) with 2-hydroxyethyl methacrylate(HEMA) were prepared, and their photosensitizing efficiencies were examined with respect to oxidation-reduction between L-ascorbic acid and Fast Red A in dimethylformamide. The photosensitizing efficiency was found to decrease with increasing HEMA content in the polymer. Intramolecular chemical quenching of anthraquinone triplet by HEMA units leading to the formation of O-alkylated anthra-hydroquinone

Takayuki Nakahira; Hirofumi Maruyama; Susumu Iwabuchi; Kuniharu Kojima

1980-01-01

395

Dose and Time-Course Evaluation of a Redox-Based Estradiol-Chemical Delivery System for the Brain. II. Pharmacodynamic Responses  

Microsoft Academic Search

Clinically, brain-enhanced delivery and sustained release of estradiol (E2) are desirable for effective treatments of menopausal hot flushes and prostatic adenocarcinoma and for fertility regulation. Thus, we conducted studies to determine the dose- and time-dependent effects of a brain-enhanced estradiol-chemical delivery system (E2-CDS) on anterior pituitary hormones secretion in ovariectomized (OVX) rats. The E2-CDS has consistently demonstrated preferential retention of

Mohamad H. Rahimy; James W. Simpkins; Nicholas Bodor

1990-01-01

396

Structural changes without stable intermediate state in inelastic material. Part II. Applications to displacive and diffusional–displacive phase transformations, strain-induced chemical reactions and ductile fracture  

Microsoft Academic Search

A number of simple examples demonstrate the applicability of the general theory developed in Part I of this paper to various structural changes in solids, namely to displacive and generalized second-order phase transformations, twinning and reorientation of crystal lattice, ductile fracture, and strain-induced chemical reactions. The theory is extended to diffusional-displacive phase transitions. The following problems for elastic and elastoplastic

Valery I. Levitas

2000-01-01

397

Copper(I)\\/(II) or silver(I) ions towards 2-mercaptopyrimidine: An exploration of a chemical variability with possible biological implication  

Microsoft Academic Search

Direct reaction of copper(I) chloride with 2-mercaptopyrimidine (pmtH) in the presence of the triphenylphosphine (tpp) in 1:1:2M ratio forms the mixed ligand Cu(I) complex with formula [CuCl(tpp)2(pmtH)] (1). The dimeric {[Cu(tpp)(pmt)]2 0.5(MeOH)} (2) complex was derived from the reaction of 1 with twofold molar amount of sodium hydroxide. However, the reaction of copper(II) sulfate or nitrate with pmtH and tpp

G. K. Batsala; V. Dokorou; N. Kourkoumelis; M. J. Manos; A. J. Tasiopoulos; T. Mavromoustakos; M. Sim?i?; S. Goli?-Grdadolnik; S. K. Hadjikakou

398

Chemical and dynamical processes in the atmospheres of, I. Ancient and present-day earth, II. Jupiter and Galilean satellites, III. Extrasolar "Hot Jupiters"  

NASA Astrophysics Data System (ADS)

When exposed to stellar UV radiation, chemical processes will be governed not only by temperature/pressure but also the spectrum of the incoming dissociative photon flux; the system will approach kinetic, or photochemical, equilibrium, instead of thermochemical equilibrium. Over the previous decades, photochemistry has proven to be a powerful tool for predicting the chemical composition in the atmospheres of solar planets and their satellites. For example, the ozone layer in our own atmosphere (stratosphere) is a photochemical product of oxygen. In this thesis, I apply a photochemical model to the study of a variety of astronomical objects: the Earth, Jupiter, the Galilean satellite Callisto, and extrasolar "hot Jupiters" (HD 209458b). For the Earth, a method for utilizing the isotopic composition of CO 2 and N 2 O to monitor global changes due to these two greenhouse gases is developed. For objects other than the Earth, the model facilitates in the interpretation of data acquired by remote (telescopic) and in situ (spacecraft) measurements. The ultimate goal is to understand the conditions of chemical and physical environments in protoplanetary nebulae, which will provide clues as to the formation of planetary systems; the synthesis of organic compounds which could lead to the appearance of life; and the evolution of planetary atmospheres such as the formation of Titan's nitrogen-rich atmosphere.

Liang, Mao-Chang

399

Benefits and risks of fish consumption Part II. RIBEPEIX, a computer program to optimize the balance between the intake of omega-3 fatty acids and chemical contaminants.  

PubMed

In recent years, and based on the importance of fish as a part of a healthy diet, there has been a notable promotion of fish and seafood consumption. However, a number of recent studies have shown that fish may be a potential source of exposure to chemical pollutants, some of them with well known adverse effects on human health. Recently, we determined in 14 edible marine species the concentrations of eicosapentaenoic acid (EPA) and docosohexaenoic acid (DHA), as well as those of a number of chemical contaminants: Cd, Hg, Pb, polychlorinated dibenzo-p-dioxins and furans, polychlorinated biphenyls, hexachlorobenzene, polycyclic aromatic hydrocarbons, polychlorinated naphthalenes, polybrominated diphenylethers and polychlorinated diphenylethers. To quantitative establish the intake of these pollutants (risks) versus that of EPA+DHA (benefits), we designed a simple computer program, RIBEPEIX. The concentrations of EPA, DHA, and the chemical pollutants were introduced into the program. We here present how RIBEPEIX may be used as an easy tool to optimize fish consumption: most suitable species, frequency of consumption, and size of meals. RIBEPEIX can be useful not only for professionals (cardiologists, general physicians, nutritionists, toxicologists, etc.), but also for the general population. It is available at: . PMID:17178182

Domingo, José L; Bocio, Ana; Martí-Cid, Roser; Llobet, Juan M

2006-11-21

400

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

401

Chemical Abundances of the Milky Way Thick Disk and Stellar Halo. II. Sodium, Iron-peak, and Neutron-capture Elements  

NASA Astrophysics Data System (ADS)

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 ? elements by performing a one-dimensional LTE abundance analysis based on the high-resolution (R ~ 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] ~-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] gsim -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.; Aoki, W.; Chiba, M.

2013-07-01

402

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

403

Journal of Chemical Education  

NSDL National Science Digital Library

The Journal of Chemical Education digital library provides a collection of chemistry related education resources online. Users may search or browse the online collection. Materials are available for a range of educational levels and on a variety of chemistry related topics.

2011-03-10

404

CHEMICAL EVOLUTION IN HIERARCHICAL MODELS OF COSMIC STRUCTURE. II. THE FORMATION OF THE MILKY WAY STELLAR HALO AND THE DISTRIBUTION OF THE OLDEST STARS  

SciTech Connect

This paper presents theoretical star formation and chemical enrichment histories for the stellar halo of the Milky Way (MW) based on new chemodynamical modeling. The goal of this study is to assess the extent to which metal-poor stars in the halo reflect the star formation conditions that occurred in halo progenitor galaxies at high redshift, before, and during the epoch of re-ionization. Simple prescriptions that translate dark-matter (DM) halo mass into baryonic gas budgets and star formation histories yield models that resemble the observed MW halo in its total stellar mass, metallicity distribution, and the luminosity function and chemical enrichment of dwarf satellite galaxies. These model halos in turn allow an exploration of how the populations of interest for probing the epoch of re-ionization are distributed in physical and phase space, and of how they are related to lower-redshift populations of the same metallicity. The fraction of stars dating from before a particular time or redshift depends strongly on radius within the galaxy, reflecting the 'inside-out' growth of cold DM halos, and on metallicity, reflecting the general trend toward higher metallicity at later times. These results suggest that efforts to discover stars from z>6-10 should select for stars with [Fe/H] approx<-3 and favor stars on more tightly bound orbits in the stellar halo, where the majority are from z>10 and 15%-40% are from z>15. The oldest, most metal-poor stars-those most likely to reveal the chemical abundances of the first stars-are most common in the very center of the Galaxy's halo: they are in the bulge, but not of the bulge. These models have several implications for the larger project of constraining the properties of the first stars and galaxies using data from the local universe.

Tumlinson, Jason [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

2010-01-10

405

Chemical Changes  

NSDL National Science Digital Library

In this activity you will learn what a chemical change is. The first step to understanding chemical changes is to recognize the difference between chemical properties and physical properties. Click here for an example: Chemical and Physical Changes What are the signs of a chemical reaction occuring? Signs of Chemical Change What variables affect a chemical reaction? Variables ...

Jolley, Mr.

2005-10-25

406

Physico-chemical modeling of the role of free radicals in photodynamic therapy. II. Interactions of ground state sensitizers with free radicals studied by chemiluminescence spectrometry.  

PubMed

Chemiluminescence (CL) studies of the interaction between ground state hematoporphyrin photosensitizer (Hp) and peroxy radicals generated by the initiated oxidation of ethylbenzene at 60-80 degrees C revealed, that Hp is a singlet-singlet acceptor similarly to 9,10-diphenylanthracene. Furthermore, the fast decrease in the CL signal in the presence of Hp indicated that its consumption also took place due to chemical transformation, presumably by the attack of peroxy radicals on Hp. The rate constant of this attack has been calculated and it supports the view that such interaction can lead to an essential contribution to the bleaching processes in vivo. PMID:8280173

Vasvári, G; Elzemzam, S; Gál, D

1993-12-30

407

TAN-931, a novel nonsteroidal aromatase inhibitor produced by Penicillium funiculosum No. 8974. II. Structure elucidation, chemical modification and biological activity.  

PubMed

The structure of TAN-931, a novel nonsteroidal aromatase inhibitor, was determined by chemical reactions and spectral analyses including 2D NMR experiments to be 4-(2,6-dihydroxybenzoyl)-3-formyl-5-hydroxybenzoic acid. Several derivatives of TAN-931 were prepared, and it was found that the 3-formyl and 2'- and/or 6'-hydroxyl groups play an important role in its inhibitory activity. Among the compounds synthesized, 4-(2,6-dihydroxybenzoyl)-3-formyl-5-methoxy-N,N-dimethyl-benzamide was found to be more effective than TAN-931 when administered orally. PMID:2071488

Hida, T; Ishii, T; Kanamaru, T; Muroi, M

1991-06-01

408

Collection, Isolation and Culture of Marine Algae.  

ERIC Educational Resources Information Center

|Methods of collecting, isolating, and culturing microscopic and macroscopic marine algae are described. Three different culture media list of chemicals needed and procedures for preparing Erdschreiber's and Provasoli's E. S. media. (BC)|

James, Daniel E.

1984-01-01

409

Evaluation of A MBER force field parameters for copper(II) with pyridylmethyl-amine and benzimidazolylmethyl-amine ligands: A quantum chemical study  

NASA Astrophysics Data System (ADS)

We present the theoretical evaluations on the two new sets of A MBER force field parameters for the two copper(II) nucleases, Cu(BPA)Cl 2 (BPA = bis(2-pyridylmethyl)amine) and Cu(IDB)Cl 2 (IDB = N, N-bis(2-benzimidazolylmethyl)amine) based on the DFT/B3LYP level of theory, incorporating with atomic charges calculated by the RESP method. The new force field parameters have been successfully applied in the testing molecular dynamic simulations for the nuclease-DNA combining systems. The developed force field parameters in this work can be applied in DNA-binding modeling for other artificial copper nucleases with same Cu-N type environments.

Zhu, Yanyan; Su, Yanwei; Li, Xichen; Wang, Yan; Chen, Guangju

2008-04-01

410

Synthesis of some fluorescent benzimidazole derivatives using cobalt(ii) hydroxide as highly efficient catalyst - spectral and physico-chemical studies and ESIPT process.  

PubMed

Some fluorescent benzimidazole derivatives have been designed and synthesized using cobalt(ii) hydroxide as highly efficient catalyst. Synthesized compounds have been characterized by (1)H and (13)C-NMR and mass spectral analysis. The solvent effect on the absorption and fluorescence bands has been analyzed and supplemented by computational studies. Solvatochromic effects on the spectral position and profile of the stationary fluorescence spectra clearly indicate the charge transfer (CT) character of the emitting singlet states of all of the compounds studied in both polar and non-polar environments. The fluorescence decays for the benzimidazoles fit satisfactorily to a single exponential kinetics. HOMO and LUMO orbital pictures [DFT/B3LYP/6-31G(d,p)] evidence the existence of excited state intramolecular proton transfer (ESIPT) in benzimidazole derivatives containing a hydroxy group. PMID:23824328

Jayabharathi, J; Thanikachalam, V; Jayamoorthy, K

2013-10-23

411

Analysis of gasifier samples collected with a high-temperature\\/high-pressure cascade impactor: electron spectroscopy for chemical analysis, energy dispersive x-ray analysis, and scanning electron microscopy  

Microsoft Academic Search

A particulate sample was collected from the process stream of a low Btu gasifier in a cascade impactor operated at 400°C and 10-12 atmospheres pressure. Stainless stell shim stock was used as collection substrate. The sample, which weighed less than 1 mg, was successfully mounted and examined by ESCA, EDXA, and SEM. The ESCA spectra of the samples and of

S. J. Rothenberg; C. R. Brundle; P. B. Denee; R. L. Carpenter; G. J. Newton; R. F. Henderson

1984-01-01

412

Chemical process control education and practice  

Microsoft Academic Search

Chemical process control textbooks and courses differ significantly from their electrical or mechanical control equivalents. The primary goals of this article are to i) emphasize the distinctly challenging characteristics of chemical processes, ii) present a typical process control curriculum and iii) discuss how chemical process control courses can be revised to better meet the needs of a typical BSc-level chemical

B. Wayne Bequette; Babatunde A. Ogunnaike

2001-01-01

413

Synthesis, crystal structure, and magnetic properties of an alkoxo-hydroxo-bridged octanuclear copper(II) complex showing chemically significant hydrogen-bonding interactions involving a metallamacrocyclic core.  

PubMed

A novel 16-member metallamacrocyclic octanuclear copper(II) complex of formulation [Cu8L4(OH)4] (1) has been prepared from a reaction of [Cu2L(O2CMe)] and NaOH in methanol, where L is a pentadentate trianionic Schiff base ligand N,N'-(2-hydroxypropane-1,3-diyl)bis(salicylaldimine). The complex has been characterized by analytical, structural, and spectral methods. It crystallizes in the monoclinic space group C2/c with the following unit cell dimensions: a = 30.365(3) A; b = 14.320(2) A; c = 19.019(2) A; beta = 125.33(2) degrees; V = 6746.7(13) A3; Z = 4. A total of 4589 unique data with l > 2 sigma (l) were used to refine the structure to R1(F0) = 0.0525 and wR2 = 0.1156. The structure consists of four binuclear [Cu2L]+ units linked covalently by four hydroxide ligands to form an octanuclear core which is stabilized by strong hydrogen-bonding interactions involving the hydroxide ligands. Each binuclear unit has a pentadentate ligand L showing N2O3 coordination with an endogenous alkoxide bridging atom. The magnetic susceptibility data of 1, obtained in the temperature range 14-306 K, show the presence of antiferromagnetic exchange interactions between adjacent spin-1/2 Cu(II) ions. The mu eff values are 1.54 and 0.26 microB (per copper) at 295 and 15 K, respectively. The magnetic data have been theoretically fitted using a Heisenberg spin-1/2 Hamiltonian with nearest-neighbor antiferromagnetic interactions. The spin coupling in the metallamacrocyclic ring has been modeled using four different coupling constants (J) on the basis of the structural parameters of the octanuclear core. The coupling constants obtained are J1 = -318.8, J2 = -293.3, J3 = -111.6, and J4 = -63.8 cm-1. The theoretical modeling of the susceptibility data gives a higher magnitude of the antiferromagnetic interaction within the binuclear [Cu2L]+ unit compared to those involving adjacent dimeric units. PMID:12693228

Mukherjee, Arindam; Rudra, Indranil; Nethaji, Munirathinam; Ramasesha, Suryanarayanasastry; Chakravarty, Akhil R

2003-01-27

414

Waste tank vapor project: Vapor characterization of Tank 241-C-103: Data report for OVS samples collected from Sample Job 7b, Parts I and II, received 5/18/94 and 5/24/94  

SciTech Connect

On 5/18/94, Westinghouse Hanford Company (WHC) delivered samples to Pacific Northwest Laboratory (PNL) that were collected from waste Tank 241-C-103 on 5/16/94. These samples were from Sample Job (SJ) 7b, Part 1. On 5/24/94, WHC delivered samples to PNL that were collected from waste Tank 241-C-103 on 5/18/94. These samples were from SJ7b, Part 2. A summary of data derived from the sampling of waste Tank 241-C-103 for gravimetric (H{sub 2}O) and normal paraffin hydrocarbon (NPH) concentrations are shown for SJ7b. Gravimetric analysis was performed on the samples within 24 hours of receipt by PNL. The NPH concentration of 10 samples collected for Part 1 was slightly higher than the average concentration for 15 samples collected in Part 2, 812 ({+-} 133) mg/m{sup 3} and 659 ({+-} 88) mg/m{sup 3}, respectively. The higher concentrations measured in Part 1 samples may be because the samples in Part 1 were collected at a single level, 0.79 meters above the air-liquid interface. Part 2 samples were collected at three different tank levels, 0.79, 2.92, and 5.05 m above the air-liquid interface. In Part 2, the average NPH concentrations for 5 samples collected at each of three levels was similar: 697 (60) mg/m{sup 3} at the low level, 631 (51) mg/m{sup 3} at the mid level, and 651 (134) mg/m{sup 3} at the high level. It is important to note that the measured tridecane to dodecane concentration remained constant in all samples collected in Parts 1 and 2. That ratio is 1.2 {+-} 0.05. This consistent ratio indicates that there were no random analytical biases towards either compound.

Clauss, T.R.; Edwards, J.A.; Fruchter, J.S.

1994-09-01

415

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

416

Collective Dynamics in Ionic Fluids  

Microsoft Academic Search

A solution of strong electrolytes can be considered as a multicomponent system composed of a neutral solvent and a number\\u000a of ionic species, the concentration of which is constrained by the requirement of overall electroneutrality. The general theoretical\\u000a framework is developed for the study of collective dynamics in multi-component, chemically nonreactive fluids. On this basis\\u000a we consider a few simplified

I. Mryglod; T. Bryk; V. Kuporov

417

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

418

Collective patterns and decision-making  

Microsoft Academic Search

Autocatalytic interactions between the members of an animal group or society, and particularly chemically or visually mediated allelomimesis, can be an important factor in the organisation of their collective activity. Furthermore, the interactions between the individuals and the environment allow different collective patterns and decisions to appear under different conditions, with the same individual behaviour. While most clearly demonstrable in

J. L. Deneubourg; S. Goss

1989-01-01

419

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

420

The Nainital-Cape Survey. II. Report for pulsation in five chemically peculiar A-type stars and presentation of 140 null results  

NASA Astrophysics Data System (ADS)

Aims.We search for photometric variability in chemically peculiar A type stars in the northern hemisphere. Methods: .High-speed photometric observations of Ap and Am star candidates have been carried out from ARIES (Manora Peak, Nainital) using a three-channel fast photometer attached to the ARIES 104-cm Sampurnanand telescope. Results: .This paper presents three new variables: HD 113878, HD 118660 and HD 207561. During the time span of the survey (1999 December to 2004 January) pulsations of the ? Sct type were also found for the two evolved Am stars HD 102480 and HD 98851, as reported in Joshi et al. (2002, 2003). Additionally, we present 140 null results of the survey for this time span. Conclusions: .The star HD 113878 pulsates with a period of 2.31 h, which is typical of ? Sct stars. HD 118660 exhibits multi-periodic variability with a prominent period of nearly 1 h. These periods need to be investigated and make HD 118660 a particularly interesting target for further observations. For HD 207561, a star classified as Am, a probable pulsation with a period of 6 min was found in the light curves obtained on two consecutive nights. Both HD 102480 and HD 98851 exhibit unusual alternating high and low amplitude maxima, with a period ratio of 2:1. The analysis of the null results confirms the photometric quality of the Nainital site.

Joshi, S.; Mary, D. L.; Martinez, P.; Kurtz, D. W.; Girish, V.; Seetha, S.; Sagar, R.; Ashoka, B. N.

2006-08-01

421

[Comparative investigation of structural and gene somatic mutations in workers of nuclear chemical plants. II. Frequency of lymphocytes mutant in T-cell receptor loci].  

PubMed

Frequency of lymphocytes mutant at T-cell receptor (TCR) loci was defined in 42 workers of nuclear chemical plants. In 11 persons mainly exposed to external radiation the mean frequency of TCR-mutant lymphocytes was statistically significant by higher compared with control group of unexposed donors: 9.1 x 10(-4) vs 3.5 x 10(-4) correspondently (p < 0.01). Frequency of TCR-mutant lymphocytes did not correlate neither the frequency of structural mutations non doses of external exposure. In group of workers exposed to combined external and internal radiation (n = 31) the average frequency of TCR-mutant lymphocytes was higher compared with control level: 8.9 x 10(-4) vs 3.5 x 10(-4) correspondently (p < 0.01). Correlations between the frequency of TCR-mutant cells and Pu content in organism (r = 0.5; p = 0.005) and between the frequency of chromosome aberration of unstable and stable types (r = 0.5; p = 0.002 and r = 0.6; p = 0.036, correspondently) were set. Comparison of results of analysis of structural and gene mutations allows us to supose that in case of external exposure the observed disturbances can result from genome instability in remote period after irradiation. In case of combined exposure the genetic changes were possibly caused by the constant action of alpha-radiation from Pu containing in the body. PMID:15906856

Smirnova, S G; Zamulaeva, I A; Orlova, N V; Saenko, A S; Sevan'kaev, A V; Gasteva, G N; Nugis, V Iu; Molokanov, A A

422

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

423

A fresh look at dense hydrogen under pressure. II. Chemical and physical models aiding our understanding of evolving H-H separations  

NASA Astrophysics Data System (ADS)

In order to explain the intricate dance of intramolecular (intra-proton-pair) H-H separations observed in a numerical laboratory of calculationally preferred static hydrogen structures under pressure, we examine two effects through discrete molecular models. The first effect, we call it physical, is of simple confinement. We review a salient model already in the literature, that of LeSar and Herschbach, of a hydrogen molecule in a spheroidal cavity. As a complement, we also study a hydrogen molecule confined along a line between two helium atoms. As the size of the cavity/confining distance decreases (a surrogate for increasing pressure), in both models the equilibrium proton separation decreases and the force constant of the stretching vibration increases. The second effect, which is an orbital or chemical factor, emerges from the electronic structure of the known molecular transition metal complexes of dihydrogen. In these the H-H bond is significantly elongated (and the vibron much decreased in frequency) as a result of depopulation of the ?g bonding molecular orbital of H2, and population of the antibonding ?u* MO. The general phenomenon, long known in chemistry, is analyzed through a specific molecular model of three hydrogen molecules interacting in a ring, a motif found in some candidate structures for dense hydrogen.

Labet, Vanessa; Hoffmann, Roald; Ashcroft, N. W.

2012-02-01

424

Anthropological Collections Management  

NSDL National Science Digital Library

This online article explains the meticulous care and tracking that goes into storing the 530,000 items in the museum's anthropology collection. Along with discussing the inherent differences between the items in each of the collection's three subdivisions (archaeology, ethnology, and biological anthropology), the article covers the nature of collections, preserving anthropology collections and computerizing collections management

425

Mostly Plants. Individualized Biology Activities on: I. Investigating Bread Mold; II. Transpiration; III. Botany Project; IV. Collecting/Preserving/Identifying Leaves; [and] V. Student Science Laboratory Write-Ups.  

ERIC Educational Resources Information Center

Individualized biology activities for secondary students are presented in this teaching guide. The guide is divided into five sections: (1) investigating bread mold; (2) investigating transpiration; (3) completing a botany project; (4) collecting, preserving, and identifying leaves; and (5) writing up science laboratory investigations. The…

Gibson, Paul R.

426

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 t