Mechanical-chemical analyses and sub-chronic systemic toxicity of chemical treated organic bovine bone.

PubMed

Lee, Kwang-il; Lee, Jung-soo; Lee, Keun-soo; Jung, Hong-hee; Ahn, Chan-min; Kim, Young-sik; Shim, Young-bock; Jang, Ju-woong

2015-12-01

Sequentially chemical-treated bovine bone was not only evaluated by mechanical and chemical analyses but also implanted into the gluteal muscles of rats for 12 weeks to investigate potential local pathological effects and systemic toxicities. The test (chemical treated bone) and control (heat treated bone) materials were compared using scanning electron microscope (SEM), x-ray diffraction pattern, inductively coupled plasma analysis, and bending strength test. In the SEM images, the micro-porous structure of heat-treated bone was changed to sintered ceramic-like structure. The structure of bone mineral from test and control materials was analyzed as100% hydroxyapatite. The ratio of calcium (Ca) to potassium (P), the main inorganic elements, was same even though the Ca and P percentages of the control material was relatively higher than the test material. No death or critical symptoms arose from implantation of the test (chemical treated bone) and control (physiological saline) materials during 12 weeks. The implanted sites were macroscopically examined, with all the groups showing non-irritant results. Our results indicate that chemical processed bovine bone has a better mechanical property than the heat treated bone and the implantation of this material does not produce systemic or pathological toxicity. Copyright © 2015 Elsevier Inc. All rights reserved.

Biological Sampling and Analysis in Sinclair and Dyes Inlets, Washington: Chemical Analyses for 2007 Puget Sound Biota Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brandenberger, Jill M.; Suslick, Carolynn R.; Johnston, Robert K.

2008-10-09

Evaluating spatial and temporal trends in contaminant residues in Puget Sound fish and macroinvertebrates are the objectives of the Puget Sound Ambient Monitoring Program (PSAMP). In a cooperative effort between the ENVironmental inVESTment group (ENVVEST) and Washington State Department of Fish and Wildlife, additional biota samples were collected during the 2007 PSAMP biota survey and analyzed for chemical residues and stable isotopes of carbon (δ13C) and nitrogen (δ15N). Approximately three specimens of each species collected from Sinclair Inlet, Georgia Basin, and reference locations in Puget Sound were selected for whole body chemical analysis. The muscle tissue of specimens selected formore » chemical analyses were also analyzed for δ13C and δ15N to provide information on relative trophic level and food sources. This data report summarizes the chemical residues for the 2007 PSAMP fish and macro-invertebrate samples. In addition, six Spiny Dogfish (Squalus acanthias) samples were necropsied to evaluate chemical residue of various parts of the fish (digestive tract, liver, embryo, muscle tissue), as well as, a weight proportional whole body composite (WBWC). Whole organisms were homogenized and analyzed for silver, arsenic, cadmium, chromium, copper, nickel, lead, zinc, mercury, 19 polychlorinated biphenyl (PCB) congeners, PCB homologues, percent moisture, percent lipids, δ13C, and δ15N.« less

Initial analyses of the relationship between 'Thresholds' of toxicity for individual chemicals and 'Interaction Thresholds' for chemical mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Raymond S.H.; Dennison, James E.

2007-09-01

The inter-relationship of 'Thresholds' between chemical mixtures and their respective component single chemicals was studied using three sets of data and two types of analyses. Two in vitro data sets involve cytotoxicity in human keratinocytes from treatment of metals and a metal mixture [Bae, D.S., Gennings, C., Carter, Jr., W.H., Yang, R.S.H., Campain, J.A., 2001. Toxicological interactions among arsenic, cadmium, chromium, and lead in human keratinocytes. Toxicol. Sci. 63, 132-142; Gennings, C., Carter, Jr., W.H., Campain, J.A., Bae, D.S., Yang, R.S.H., 2002. Statistical analysis of interactive cytotoxicity in human epidermal keratinocytes following exposure to a mixture of four metals. J.more » Agric. Biol. Environ. Stat. 7, 58-73], and induction of estrogen receptor alpha (ER-{alpha}) reporter gene in MCF-7 human breast cancer cells by estrogenic xenobiotics [Gennings, C., Carter, Jr., W.H., Carney, E.W., Charles, G.D., Gollapudi, B.B., Carchman, R.A., 2004. A novel flexible approach for evaluating fixed ratio mixtures of full and partial agonists. Toxicol. Sci. 80, 134-150]. The third data set came from PBPK modeling of gasoline and its components in the human. For in vitro cellular responses, we employed Benchmark Dose Software (BMDS) to obtain BMD{sub 01}, BMD{sub 05}, and BMD{sub 10}. We then plotted these BMDs against exposure concentrations for the chemical mixture and its components to assess the ranges and slopes of these BMD-concentration lines. In doing so, we consider certain BMDs to be 'Interaction Thresholds' or 'Thresholds' for mixtures and their component single chemicals and the slope of the line must be a reflection of the potency of the biological effects. For in vivo PBPK modeling, we used 0.1x TLVs, TLVs, and 10x TLVs for gasoline and six component markers as input dosing for PBPK modeling. In this case, the venous blood levels under the hypothetical exposure conditions become our designated 'Interaction Thresholds' or 'Thresholds' for

Improving phylogenetic analyses by incorporating additional information from genetic sequence databases.

PubMed

Liang, Li-Jung; Weiss, Robert E; Redelings, Benjamin; Suchard, Marc A

2009-10-01

Statistical analyses of phylogenetic data culminate in uncertain estimates of underlying model parameters. Lack of additional data hinders the ability to reduce this uncertainty, as the original phylogenetic dataset is often complete, containing the entire gene or genome information available for the given set of taxa. Informative priors in a Bayesian analysis can reduce posterior uncertainty; however, publicly available phylogenetic software specifies vague priors for model parameters by default. We build objective and informative priors using hierarchical random effect models that combine additional datasets whose parameters are not of direct interest but are similar to the analysis of interest. We propose principled statistical methods that permit more precise parameter estimates in phylogenetic analyses by creating informative priors for parameters of interest. Using additional sequence datasets from our lab or public databases, we construct a fully Bayesian semiparametric hierarchical model to combine datasets. A dynamic iteratively reweighted Markov chain Monte Carlo algorithm conveniently recycles posterior samples from the individual analyses. We demonstrate the value of our approach by examining the insertion-deletion (indel) process in the enolase gene across the Tree of Life using the phylogenetic software BALI-PHY; we incorporate prior information about indels from 82 curated alignments downloaded from the BAliBASE database.

15 CFR 714.3 - Advance declaration requirements for additionally planned production of Schedule 3 chemicals.

Code of Federal Regulations, 2011 CFR

2011-01-01

... COMMERCE CHEMICAL WEAPONS CONVENTION REGULATIONS ACTIVITIES INVOLVING SCHEDULE 3 CHEMICALS § 714.3 Advance declaration requirements for additionally planned production of Schedule 3 chemicals. (a) Declaration... additionally planned production of Schedule 3 chemicals. 714.3 Section 714.3 Commerce and Foreign Trade...

Extraction of information from major element chemical analyses of lunar basalts

NASA Technical Reports Server (NTRS)

Butler, J. C.

1985-01-01

Major element chemical analyses often form the framework within which similarities and differences of analyzed specimens are noted and used to propose or devise models. When percentages are formed the ratios of pairs of components are preserved whereas many familiar statistical and geometrical descriptors are likely to exhibit major changes. This ratio preserving aspect forms the basis for a proposed framework. An analysis of compositional variability within the data set of 42 major element analyses of lunar reference samples was selected to investigate this proposal.

Chemical and physical analyses of selected plants and soils from Puerto Rico (1981-2000)

Treesearch

M.J. Sanchez; E. Lopez; A.E. Lugo

2015-01-01

This report contains the results of analyses conducted at the chemistry laboratory of the International Institute of Tropical Forestry in Puerto Rico from 1981 to 2000. The data set includes 109,177 plant analyses and 70,729 soil analyses. We report vegetation chemical data by plant part, species, life zone, soil order, geology, or parent material. Soil data are...

Response of the bacterial community in oil-contaminated marine water to the addition of chemical and biological dispersants.

PubMed

Couto, Camila Rattes de Almeida; Jurelevicius, Diogo de Azevedo; Alvarez, Vanessa Marques; van Elsas, Jan Dirk; Seldin, Lucy

2016-12-15

The use of dispersants in different stages of the oil production chain and for the remediation of water and soil is a well established practice. However, the choice for a chemical or biological dispersant is still a controversial subject. Chemical surfactants that persist long in the environment may pose problems of toxicity themselves; therefore, biosurfactants are considered to constitute an environmentally friendly and effective alternative. Nevertheless, the putative effects of such agents on the microbiomes of oil-contaminated and uncontaminated marine environments have not been sufficiently evaluated. Here, we studied the effects of the surfactant Ultrasperse II ® and the surfactin (biosurfactant) produced by Bacillus sp. H2O-1 on the bacterial communities of marine water. Specifically, we used quantitative PCR and genetic fingerprint analyses to study the abundance and structure of the bacterial communities in marine water collected from two regions with contrasting climatic conditions. The addition of either chemical surfactant or biosurfactant influenced the structure and abundance of total and oil-degrading bacterial communities of oil-contaminated and uncontaminated marine waters. Remarkably, the bacterial communities responded similarly to the addition of oil and/or either the surfactant or the biosurfactant in both set of microcosms. After 30 days of incubation, the addition of surfactin enhanced the oil-degrading bacteria more than the chemical surfactant. However, no increase of hydrocarbon biodegradation values was observed, irrespective of the dispersant used. These data contribute to an increased understanding of the impact of novel dispersants on marine bacteriomes before commercial release into the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemical and Solar Electric Propulsion Systems Analyses for Mars Sample Return Missions

NASA Technical Reports Server (NTRS)

Donahue, Benjamin B.; Green, Shaun E.; Coverstone, Victoria L.; Woo, Byoungsam

2004-01-01

Conceptual in-space transfer stages, including those utilizing solar electric propulsion, chemical propulsion, and chemical propulsion with aerobraking or aerocapture assist at Mars, were evaluated. Roundtrip Mars sample return mission vehicles were analyzed to determine how specific system technology selections influence payload delivery capability. Results show how specific engine, thruster, propellant, capture mode, trip time and launch vehicle technology choices would contribute to increasing payload or decreasing the size of the required launch vehicles. Heliocentric low-thrust trajectory analyses for Solar Electric Transfer were generated with the SEPTOP code.

Disclosure of hydraulic fracturing fluid chemical additives: analysis of regulations.

PubMed

Maule, Alexis L; Makey, Colleen M; Benson, Eugene B; Burrows, Isaac J; Scammell, Madeleine K

2013-01-01

Hydraulic fracturing is used to extract natural gas from shale formations. The process involves injecting into the ground fracturing fluids that contain thousands of gallons of chemical additives. Companies are not mandated by federal regulations to disclose the identities or quantities of chemicals used during hydraulic fracturing operations on private or public lands. States have begun to regulate hydraulic fracturing fluids by mandating chemical disclosure. These laws have shortcomings including nondisclosure of proprietary or "trade secret" mixtures, insufficient penalties for reporting inaccurate or incomplete information, and timelines that allow for after-the-fact reporting. These limitations leave lawmakers, regulators, public safety officers, and the public uninformed and ill-prepared to anticipate and respond to possible environmental and human health hazards associated with hydraulic fracturing fluids. We explore hydraulic fracturing exemptions from federal regulations, as well as current and future efforts to mandate chemical disclosure at the federal and state level.

49 CFR 107.807 - Approval of non-domestic chemical analyses and tests.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Approval of non-domestic chemical analyses and tests. 107.807 Section 107.807 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS AND OIL TRANSPORTATION HAZARDOUS MATERIALS PROGRAM...

76 FR 20992 - Sun Chemical Corp.; Filing of Color Additive Petition

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-14

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2011-C-0050] Sun Chemical Corp.; Filing of Color Additive Petition AGENCY: Food and Drug Administration, HHS... filed a petition proposing that the color additive regulations for D&C Red No. 6 and D&C Red No. 7 be...

Fundamentals of the knowledge about chemical additives present in rubber gloves.

PubMed

Oliveira, Hegles Rosa de; Alchorne, Alice de Oliveira de Avelar

2011-01-01

One of the most frequent causes of allergic contact dermatitis of occupational origin are rubber additives, which are present in Personal Protective Equipment (PPE). The most allergenic additives of natural and synthetic gloves are thiurams, carbamates and mercapto group. To investigate the state of knowledge about the chemical additives used in the manufacture of synthetic rubber gloves. This was a qualitative research study in which professionals working in the manufacture, research, prescription and commercialization of gloves answered an open questionnaire. 30 individuals were interviewed: 4 researchers in occupational medicine, 5 occupational physicians, 2 occupational safety technicians, a rubber workers' union physician, an occupational safety engineer, a pro duction engineer of rubber gloves, 4 importers of gloves, a manufacturer of gloves, 3 businessmen who sell PPE, 3 salesclerks working in stores that sell PPE, 2 businessmen who own stores that sell products for allergic individuals, and 3 dermatologists. Knowledge of the chemical composition of rubber gloves is scant. The labeling of gloves, with the description of their chemical composition, would facilitate choosing the best type of glove for each person. This low-cost action to businesses would be a gain from the standpoint of public health, with huge repercussions for users of rubber gloves.

Explanation of non-additive effects in mixtures of similar mode of action chemicals.

PubMed

Kamo, Masashi; Yokomizo, Hiroyuki

2015-09-01

Many models have been developed to predict the combined effect of drugs and chemicals. Most models are classified into two additive models: independent action (IA) and concentration addition (CA). It is generally considered if the modes of action of chemicals are similar then the combined effect obeys CA; however, many empirical studies report nonlinear effects deviating from the predictions by CA. Such deviations are termed synergism and antagonism. Synergism, which leads to a stronger toxicity, requires more careful management, and hence it is important to understand how and which combinations of chemicals lead to synergism. In this paper, three types of chemical reactions are mathematically modeled and the cause of the nonlinear effects among chemicals with similar modes of action was investigated. Our results show that combined effects obey CA only when the modes of action are exactly the same. Contrary to existing knowledge, combined effects are generally nonlinear even if the modes of action of the chemicals are similar. Our results further show that the nonlinear effects vanish out when the chemical concentrations are low, suggesting that the current management procedure of assuming CA is rarely inappropriate because environmental concentrations of chemicals are generally low. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

78 FR 68461 - Guidance for Industry: Studies To Evaluate the Utility of Anti-Salmonella Chemical Food Additives...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-14

...] Guidance for Industry: Studies To Evaluate the Utility of Anti- Salmonella Chemical Food Additives in Feeds... Industry: Studies to Evaluate the Utility of Anti-Salmonella Chemical Food Additives in Feeds,'' and is... of Anti-Salmonella Chemical Food Additives in Feeds (GFI 80) is to help sponsors design efficacy...

Spacelab Charcoal Analyses

NASA Technical Reports Server (NTRS)

Slivon, L. E.; Hernon-Kenny, L. A.; Katona, V. R.; Dejarme, L. E.

1995-01-01

This report describes analytical methods and results obtained from chemical analysis of 31 charcoal samples in five sets. Each set was obtained from a single scrubber used to filter ambient air on board a Spacelab mission. Analysis of the charcoal samples was conducted by thermal desorption followed by gas chromatography/mass spectrometry (GC/MS). All samples were analyzed using identical methods. The method used for these analyses was able to detect compounds independent of their polarity or volatility. In addition to the charcoal samples, analyses of three Environmental Control and Life Support System (ECLSS) water samples were conducted specifically for trimethylamine.

CAES 2014 Chemical Analyses of Thermal Wells and Springs in Southeastern Idaho

DOE Data Explorer

Baum, Jeffrey

2014-03-10

This dataset contains chemical analyses for thermal wells and springs in Southeastern Idaho. Data includes all major cations, major anions, pH, collection temperature, and some trace metals, These samples were collected in 2014 by the Center for Advanced Energy Studies (CAES), and are part of a continuous effort to analyze the geothermal potential of Southeastern Idaho.

Assets and pitfalls of chemical and microscopic analyses on gunshot residues in skeletonized bodies: a report of five cases.

PubMed

Amadasi, Alberto; Gibelli, Daniele; Mazzarelli, Debora; Porta, Davide; Gaudio, Daniel; Salsarola, Dominic; Brandone, Alberto; Rizzi, Agostino; Cattaneo, Cristina

2015-07-01

In case of gunshot wounds, forensic anthropologists and pathologists have many tools at hand, and the assistance that chemical and microscopic investigations can provide in such scenarios is often valuable and crucial. However, the results of such analyses in the search of gunshot residues (GSR) ought not to be acritically considered. We report five cases where chemical (sodium rhodizonate) and microscopic (scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX)) analyses were performed for the search of GSR. Four cases concerned the forensic field and analyses on buried, charred, or submerged remains, whereas one case concerned the historical remains of a soldier of the First World War. In every case, the search for GSR with these techniques showed their persistence even after long periods and preservation in peculiar environments. However, chemical analyses provided their contribution, but in two cases, anthropological analyses provided crucial and solving results. The five cases show the indisputable usefulness of chemical and microscopic analyses in the search of GSR in gunshot wounds and especially how such residues may survive in time and in adverse environmental conditions. However, experts should always be dubious about some pitfalls (such as contamination) one can frequently find in these scenarios.

Chemical and physical analyses of selected plants and soils from Puerto Rico (1981-1990)

Treesearch

M. J. Sanchez; E. Lopez; A. E. Lugo

1997-01-01

This report contains the result of many analyses conducted at the laboratory of the IITF of Puerto Rico between 1981 and 1990. our objective was to make available the chemical and physical data developed for tropical forest ecosystems.

Review on effect of chemical, thermal, additive treatment on mechanical properties of basalt fiber and their composites

NASA Astrophysics Data System (ADS)

Jain, Naman; Singh, Vinay Kumar; Chauhan, Sakshi

2017-12-01

Basalt fiber is emerging out the new reinforcing material for composites. To overcome some of the disadvantages of fibers such as poor bonding to polymers, low thermal stability and high moisture absorption fiber characteristics are modified with chemical, thermal and additive treatments. Chemical treatment corrosive resistance to alkali and acid were investigated which were used to clean and modify the surface of fiber for higher bonding with resins. To improve the thermal stability and reduce moisture uptake thermal treatment such as plasma and non thermal plasma were used which increased the surface roughness and change the chemical composition of surface of basalt fiber. Additive treatment is used to improve the mechanical properties of fibers, in basalt fiber additive treatment was done with SiO2 additive because of its chemical composition which contains major content of SiO2. In present investigation review on the effect of different treatment such as chemical, thermal and additive were studied. Effect of these treatment on chemical composition of the surface of basalt fiber and corrosion to acidic and alkali solution were studied with their effect on mechanical properties of basalt fiber and their composite.

15 CFR 714.3 - Advance declaration requirements for additionally planned production of Schedule 3 chemicals.

Code of Federal Regulations, 2010 CFR

2010-01-01

... additionally planned production of Schedule 3 chemicals. 714.3 Section 714.3 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE CHEMICAL WEAPONS CONVENTION REGULATIONS ACTIVITIES INVOLVING SCHEDULE 3 CHEMICALS § 714.3 Advance...

The effect of lactic acid bacterial starter culture and chemical additives on wilted rice straw silage.

PubMed

Wang, Yan-Su; Shi, Wei; Huang, Lin-Ting; Ding, Cheng-Long; Dai, Chuan-Chao

2016-04-01

Lactic acid bacteria (LAB) are suitable for rice straw silage fermentation, but have been studied rarely, and rice straw as raw material for ensiling is difficult because of its disadvantages, such as low nutrition for microbial activities and low abundances of natural populations of LAB. So we investigated the effect of application of LAB and chemical additives on the fermentation quality and microbial community of wilted rice straw silage. Treatment with chemical additives increased the concentrations of crude protein (CP), water soluble carbohydrate (WSC), acetic acid and lactic acid, reduced the concentrations of acid detergent fiber (ADF) and neutral detergent fiber (NDF), but did not effectively inhibit the growth of spoilage organisms. Inoculation with LABs did not improve the nutritional value of the silage because of poor growth of LABs in wilted rice straw. Inoculation with LAB and addition of chemical materials improved the quality of silage similar to the effects of addition of chemical materials alone. Growth of aerobic and facultatively anaerobic bacteria was inhibited by this mixed treatment and the LAB gradually dominated the microbial community. In summary, the fermentation quality of wilted rice straw silage had improved by addition of LAB and chemical materials. © 2015 Japanese Society of Animal Science.

Multivariate Quantitative Chemical Analysis

NASA Technical Reports Server (NTRS)

Kinchen, David G.; Capezza, Mary

1995-01-01

Technique of multivariate quantitative chemical analysis devised for use in determining relative proportions of two components mixed and sprayed together onto object to form thermally insulating foam. Potentially adaptable to other materials, especially in process-monitoring applications in which necessary to know and control critical properties of products via quantitative chemical analyses of products. In addition to chemical composition, also used to determine such physical properties as densities and strengths.

Arsenic Remediation Enhancement Through Chemical Additions to Pump and Treat Operations

NASA Astrophysics Data System (ADS)

Wovkulich, K.; Mailloux, B. J.; Stute, M.; Simpson, H. J.; Keimowitz, A. R.; Powell, A.; Lacko, A.; Chillrud, S. N.

2008-12-01

Arsenic is a contaminant found at more than 500 US Superfund sites. Since pump and treat technologies are widely used for remediation of contaminated groundwater, increasing the efficiency of contaminant removal at such sites should allow limited financial resources to clean up more sites. The Vineland Chemical Company Superfund site is extensively contaminated with arsenic after waste arsenic salts were stored and disposed of improperly for much of the company's 44 year manufacturing lifetime. Despite approximately eight years of pump and treat remediation, arsenic concentrations in the recovery wells can still be greater than 1000 ppb. The arsenic concentrations in the groundwater remain high because of slow desorption of arsenic from contaminated aquifer solids. Extrapolation of laboratory column experiments suggest that continuing the current groundwater remediation practice based on flushing ambient groundwater through the system may require on the order of hundreds of years to clean the site. However, chemical additions of phosphate or oxalic acid into the aquifer could decrease the remediation time scale substantially. Laboratory results from a soil column experiment using input of 10 mM oxalic acid suggest that site clean up of groundwater could be decreased to as little as four years. Pilot scale forced gradient field experiments will help establish whether chemical additions can be effective for increasing arsenic mobilization from aquifer solids and thus substantially decrease pump and treat clean up time.

Using US EPA’s Chemical Safety for Sustainability’s Comptox Chemistry Dashboard and Tools for Bioactivity, Chemical and Toxicokinetic Modeling Analyses (Course at 2017 ISES Annual Meeting)

EPA Science Inventory

Title: Using US EPA’s Chemical Safety for Sustainability’s Comptox Chemistry Dashboard and Tools for Bioactivity, Chemical and Toxicokinetic Modeling Analyses • Class format: half-day (4 hours) • Course leader(s): Barbara A. Wetmore and Antony J. Williams,...

Optimizing use of the structural chemical analyser (variable pressure FESEM-EDX Raman spectroscopy) on micro-size complex historical paintings characterization.

PubMed

Guerra, I; Cardell, C

2015-10-01

The novel Structural Chemical Analyser (hyphenated Raman spectroscopy and scanning electron microscopy equipped with an X-ray detector) is gaining popularity since it allows 3-D morphological studies and elemental, molecular, structural and electronic analyses of a single complex micro-sized sample without transfer between instruments. However, its full potential remains unexploited in painting heritage where simultaneous identification of inorganic and organic materials in paintings is critically yet unresolved. Despite benefits and drawbacks shown in literature, new challenges have to be faced analysing multifaceted paint specimens. SEM-Structural Chemical Analyser systems differ since they are fabricated ad hoc by request. As configuration influences the procedure to optimize analyses, likewise analytical protocols have to be designed ad hoc. This paper deals with the optimization of the analytical procedure of a Variable Pressure Field Emission scanning electron microscopy equipped with an X-ray detector Raman spectroscopy system to analyse historical paint samples. We address essential parameters, technical challenges and limitations raised from analysing paint stratigraphies, archaeological samples and loose pigments. We show that accurate data interpretation requires comprehensive knowledge of factors affecting Raman spectra. We tackled: (i) the in-FESEM-Raman spectroscopy analytical sequence, (ii) correlations between FESEM and Structural Chemical Analyser/laser analytical position, (iii) Raman signal intensity under different VP-FESEM vacuum modes, (iv) carbon deposition on samples under FESEM low-vacuum mode, (v) crystal nature and morphology, (vi) depth of focus and (vii) surface-enhanced Raman scattering effect. We recommend careful planning of analysis strategies prior to research which, although time consuming, guarantees reliable results. The ultimate goal of this paper is to help to guide future users of a FESEM-Structural Chemical Analyser system

Botanical discrimination of Greek unifloral honeys with physico-chemical and chemometric analyses.

PubMed

Karabagias, Ioannis K; Badeka, Anastasia V; Kontakos, Stavros; Karabournioti, Sofia; Kontominas, Michael G

2014-12-15

The aim of the present study was to investigate the possibility of characterisation and classification of Greek unifloral honeys (pine, thyme, fir and orange blossom) according to botanical origin using volatile compounds, conventional physico-chemical parameters and chemometric analyses (MANOVA and Linear Discriminant Analysis). For this purpose, 119 honey samples were collected during the harvesting period 2011 from 14 different regions in Greece known to produce unifloral honey of good quality. Physico-chemical analysis included the identification and semi quantification of fifty five volatile compounds performed by Headspace Solid Phase Microextraction coupled to gas chromatography/mass spectroscopy and the determination of conventional quality parameters such as pH, free, lactonic, total acidity, electrical conductivity, moisture, ash, lactonic/free acidity ratio and colour parameters L, a, b. Results showed that using 40 diverse variables (30 volatile compounds of different classes and 10 physico-chemical parameters) the honey samples were satisfactorily classified according to botanical origin using volatile compounds (84.0% correct prediction), physicochemical parameters (97.5% correct prediction), and the combination of both (95.8% correct prediction) indicating that multi element analysis comprises a powerful tool for honey discrimination purposes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of argon addition on a-CNx film deposition by hot carbon filament chemical vapor deposition

NASA Astrophysics Data System (ADS)

Watanabe, Yoshihisa; Aono, Masami; Yamazaki, Ayumi; Kitazawa, Nobuaki; Nakamura, Yoshikazu

2002-07-01

Using a carbon filament which supplies carbon and heat, amorphous carbon nitride (a-CNx) films were prepared on Si (100) substrates by hot filament chemical vapor deposition. Deposition was performed in a low-pressure atmosphere of pure nitrogen and a gas mixture of nitrogen and argon. Effects of argon additions to the nitrogen atmosphere on the film microstructure and interface composition between the film and substrate were studied by field-emission scanning electron microscopy (FESEM) and x-ray photoelectron spectroscopy (XPS). FESEM observations reveal that the film prepared in a pure nitrogen atmosphere has uniform nucleation and a densely packed columnar pieces structure. The film prepared in the nitrogen and argon gas mixture exhibits preferential nucleation and a tapered structure with macroscopic voids. Depth analyses using XPS reveal that the film prepared in pure nitrogen possesses a broad interface, which includes silicon carbide as well as a-CNx, whereas a sharp interface is discerned in the film prepared in the mixed nitrogen and argon gas. We observed that silicon carbide formation is suppressed by an argon addition to the nitrogen atmosphere during deposition. copyright 2002 American Vacuum Society.

Lessons learned from additional research analyses of unsolved clinical exome cases.

PubMed

Eldomery, Mohammad K; Coban-Akdemir, Zeynep; Harel, Tamar; Rosenfeld, Jill A; Gambin, Tomasz; Stray-Pedersen, Asbjørg; Küry, Sébastien; Mercier, Sandra; Lessel, Davor; Denecke, Jonas; Wiszniewski, Wojciech; Penney, Samantha; Liu, Pengfei; Bi, Weimin; Lalani, Seema R; Schaaf, Christian P; Wangler, Michael F; Bacino, Carlos A; Lewis, Richard Alan; Potocki, Lorraine; Graham, Brett H; Belmont, John W; Scaglia, Fernando; Orange, Jordan S; Jhangiani, Shalini N; Chiang, Theodore; Doddapaneni, Harsha; Hu, Jianhong; Muzny, Donna M; Xia, Fan; Beaudet, Arthur L; Boerwinkle, Eric; Eng, Christine M; Plon, Sharon E; Sutton, V Reid; Gibbs, Richard A; Posey, Jennifer E; Yang, Yaping; Lupski, James R

2017-03-21

Given the rarity of most single-gene Mendelian disorders, concerted efforts of data exchange between clinical and scientific communities are critical to optimize molecular diagnosis and novel disease gene discovery. We designed and implemented protocols for the study of cases for which a plausible molecular diagnosis was not achieved in a clinical genomics diagnostic laboratory (i.e. unsolved clinical exomes). Such cases were recruited to a research laboratory for further analyses, in order to potentially: (1) accelerate novel disease gene discovery; (2) increase the molecular diagnostic yield of whole exome sequencing (WES); and (3) gain insight into the genetic mechanisms of disease. Pilot project data included 74 families, consisting mostly of parent-offspring trios. Analyses performed on a research basis employed both WES from additional family members and complementary bioinformatics approaches and protocols. Analysis of all possible modes of Mendelian inheritance, focusing on both single nucleotide variants (SNV) and copy number variant (CNV) alleles, yielded a likely contributory variant in 36% (27/74) of cases. If one includes candidate genes with variants identified within a single family, a potential contributory variant was identified in a total of ~51% (38/74) of cases enrolled in this pilot study. The molecular diagnosis was achieved in 30/63 trios (47.6%). Besides this, the analysis workflow yielded evidence for pathogenic variants in disease-associated genes in 4/6 singleton cases (66.6%), 1/1 multiplex family involving three affected siblings, and 3/4 (75%) quartet families. Both the analytical pipeline and the collaborative efforts between the diagnostic and research laboratories provided insights that allowed recent disease gene discoveries (PURA, TANGO2, EMC1, GNB5, ATAD3A, and MIPEP) and increased the number of novel genes, defined in this study as genes identified in more than one family (DHX30 and EBF3). An efficient genomics pipeline in which

Dental caries and chemical analyses in reconstruction of diet, health and hygienic behaviour in the Middle Euphrates valley (Syria).

PubMed

Tomczyk, Jacek; Szostek, Krzysztof; Komarnitki, Iulian; Mańkowska-Pliszka, Hanna; Zalewska, Marta

2013-06-01

The aim of this study was to use two methods, biological and chemical, to examine changes in diet and health in individuals from the Middle Euphrates valley (Syria). We determined the frequency distribution of dental caries. Chemical analyses were concerned with the presence of elements such as strontium, barium, calcium and stable carbon isotopes ((13)C/(14)C). We chose three consecutive periods: Late Roman (2nd-4th century AD), Islamic (600-1200 AD) and Modern Islamic (1850-1950 AD). We analysed the dental remains of 145 individuals, with a total of 2530 teeth. We used visual research (magnifying glass/sharp dental probe) and radiography. The frequencies of caries were calculated on the basis of the proportional correction factor of Erdal and Duyar. We chose 39 permanent second molars for chemical analyses. The frequency of carious lesions was similar in all three periods (6-8%). In the Modern Islamic and Islamic periods, occlusal surfaces were infected with caries most often, while the cemento-enamel junction (CEJ) and approximal surfaces were affected to a lesser degree. However, in the Late Roman period, the CEJ and approximal surfaces showed caries most frequently, in contrast to occlusal surfaces, which seldom showed signs of caries. Chemical analyses showed lower Sr/Ca ratios and Observed Ratio index values for the Modern Islamic and higher values for the Islamic and Late Roman periods. Mean stable isotope (δ(13)C) analyses demonstrated that the Modern Islamic period was strongly divergent from the other periods. These data suggest a similar socio-economic status during the Late Roman and Islamic periods. The diet of the population living in the Late Roman and Islamic periods contained a larger number of products containing strontium than calcium. In the modern population these proportions have been reversed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Selected chemical analyses of water from formations of Mesozoic and Paleozoic age in parts of Oklahoma, northern Texas, and Union County, New Mexico

USGS Publications Warehouse

Parkhurst, R.S.; Christenson, S.C.

1987-01-01

Hydrochemical data were compiled into a data base as part of the Central Midwest Regional Aquifer System Analysis project. The data consist of chemical analyses of water samples collected from wells that are completed in formations of Mesozoic and Paleozoic age. The data base includes data from the National Water Data Storage and Retrieval System, the Petroleum Data System, the National Uranium Resource Evaluation, and selected publications. Chemical analyses were selected for inclusion within the hydrochemical data base if the total concentration of the cations differed from the total 10 percent or less of the total concentration of all ions. Those analyses which lacked the necessary data for an ionic balance were included if the ratios of dissolved-solids concentration to specific conductance were between 0.55 and 0.75. The tabulated chemical analyses, grouped by county, and a statistical summary of the analyses, listed by geologic unit, are presented.

Evaluation of Two Surface Sampling Methods for Microbiological and Chemical Analyses To Assess the Presence of Biofilms in Food Companies.

PubMed

Maes, Sharon; Huu, Son Nguyen; Heyndrickx, Marc; Weyenberg, Stephanie van; Steenackers, Hans; Verplaetse, Alex; Vackier, Thijs; Sampers, Imca; Raes, Katleen; Reu, Koen De

2017-12-01

Biofilms are an important source of contamination in food companies, yet the composition of biofilms in practice is still mostly unknown. The chemical and microbiological characterization of surface samples taken after cleaning and disinfection is very important to distinguish free-living bacteria from the attached bacteria in biofilms. In this study, sampling methods that are potentially useful for both chemical and microbiological analyses of surface samples were evaluated. In the manufacturing facilities of eight Belgian food companies, surfaces were sampled after cleaning and disinfection using two sampling methods: the scraper-flocked swab method and the sponge stick method. Microbiological and chemical analyses were performed on these samples to evaluate the suitability of the sampling methods for the quantification of extracellular polymeric substance components and microorganisms originating from biofilms in these facilities. The scraper-flocked swab method was most suitable for chemical analyses of the samples because the material in these swabs did not interfere with determination of the chemical components. For microbiological enumerations, the sponge stick method was slightly but not significantly more effective than the scraper-flocked swab method. In all but one of the facilities, at least 20% of the sampled surfaces had more than 10 2 CFU/100 cm 2 . Proteins were found in 20% of the chemically analyzed surface samples, and carbohydrates and uronic acids were found in 15 and 8% of the samples, respectively. When chemical and microbiological results were combined, 17% of the sampled surfaces were contaminated with both microorganisms and at least one of the analyzed chemical components; thus, these surfaces were characterized as carrying biofilm. Overall, microbiological contamination in the food industry is highly variable by food sector and even within a facility at various sampling points and sampling times.

Chemical analyses and K-Ar ages of samples from 13 drill holes, Medicine Lake volcano, California

USGS Publications Warehouse

Donnelly-Nolan, Julie M.

2006-01-01

Chemical analyses and K-Ar ages are presented for rocks sampled from drill holes at Medicine Lake volcano, northern California. A location map and a cross-section are included, as are separate tables for drill hole information, major and trace element data, and for K-Ar dates.

Carbon speciation in ash, residual waste and contaminated soil by thermal and chemical analyses.

PubMed

Kumpiene, Jurate; Robinson, Ryan; Brännvall, Evelina; Nordmark, Désirée; Bjurström, Henrik; Andreas, Lale; Lagerkvist, Anders; Ecke, Holger

2011-01-01

Carbon in waste can occur as inorganic (IC), organic (OC) and elemental carbon (EC) each having distinct chemical properties and possible environmental effects. In this study, carbon speciation was performed using thermogravimetric analysis (TGA), chemical degradation tests and the standard total organic carbon (TOC) measurement procedures in three types of waste materials (bottom ash, residual waste and contaminated soil). Over 50% of the total carbon (TC) in all studied materials (72% in ash and residual waste, and 59% in soil) was biologically non-reactive or EC as determined by thermogravimetric analyses. The speciation of TOC by chemical degradation also showed a presence of a non-degradable C fraction in all materials (60% of TOC in ash, 30% in residual waste and 13% in soil), though in smaller amounts than those determined by TGA. In principle, chemical degradation method can give an indication of the presence of potentially inert C in various waste materials, while TGA is a more precise technique for C speciation, given that waste-specific method adjustments are made. The standard TOC measurement yields exaggerated estimates of organic carbon and may therefore overestimate the potential environmental impacts (e.g. landfill gas generation) of waste materials in a landfill environment. Copyright © 2010 Elsevier Ltd. All rights reserved.

Medicinal Plants Recommended by the World Health Organization: DNA Barcode Identification Associated with Chemical Analyses Guarantees Their Quality

PubMed Central

Palhares, Rafael Melo; Gonçalves Drummond, Marcela; dos Santos Alves Figueiredo Brasil, Bruno; Pereira Cosenza, Gustavo; das Graças Lins Brandão, Maria; Oliveira, Guilherme

2015-01-01

Medicinal plants are used throughout the world, and the regulations defining their proper use, such as identification of the correct species and verification of the presence, purity and concentration of the required chemical compounds, are widely recognized. Herbal medicines are made from vegetal drugs, the processed products of medicinal species. These processed materials present a number of challenges in terms of botanical identification, and according to the World Health Organization (WHO), the use of incorrect species is a threat to consumer safety. The samples used in this study consisted of the dried leaves, flowers and roots of 257 samples from 8 distinct species approved by the WHO for the production of medicinal herbs and sold in Brazilian markets. Identification of the samples in this study using DNA barcoding (matK, rbcL and ITS2 regions) revealed that the level of substitutions may be as high as 71%. Using qualitative and quantitative chemical analyses, this study identified situations in which the correct species was being sold, but the chemical compounds were not present. Even more troubling, some samples identified as substitutions using DNA barcoding contained the chemical compounds from the correct species at the minimum required concentration. This last situation may lead to the use of unknown species or species whose safety for human consumption remains unknown. This study concludes that DNA barcoding should be used in a complementary manner for species identification with chemical analyses to detect and quantify the required chemical compounds, thus improving the quality of this class of medicines. PMID:25978064

Physico-chemical analyses of Hispano-Moresque lustred ceramic: a precursor for Italian majolica?

NASA Astrophysics Data System (ADS)

Chabanne, D.; Bouquillon, A.; Aucouturier, M.; Dectot, X.; Padeletti, G.

2008-07-01

The paper presents a comprehensive physico-chemical investigation on a series of Hispano-Moresque objects produced in the eastern Spain workshops between the XIV and XVIII centuries and fragments from XII century, in order to compare them with the Italian Renaissance majolica production. The techniques used are mainly non-destructive (ion beam analyses and X-ray diffraction), sometimes complemented by SEM observation and microanalysis, and electrothermal atomic emission spectrometry. Such methods allow a full description of the terra cotta, of the glaze and of the different surface layers which constitute the lustre decoration indicating individual elemental composition and thickness of each layer containing or not metallic nanoparticles. Principal results show the following: i) a constant source of supply for the eastern Spain terra cotta; ii) a significant change in the composition of the Spanish glazes around the XVII century, with the disappearance of the opacifying tin oxide addition; iii) significant evolutions in the structure and composition of the lustre layers, in particular related to the presence or not of a metal-free surface glaze film and its thickness; iv) interesting analogies and differences with the Italian majolica; v) confirmation of the change in the quality of blue pigment during XVI century, already evidenced by the authors in previous publications. A discussion about the transmission of the lustre technique between eastern Spain and Italy at the Renaissance period is proposed.

Additional Measurements and Analyses of H217O and H218O

NASA Astrophysics Data System (ADS)

Pearson, John; Yu, Shanshan; Walters, Adam; Daly, Adam M.

2015-06-01

Historically the analysis of the spectrum of water has been a balance between the quality of the data set and the applicability of the Hamiltonian to a highly non-rigid molecule. Recently, a number of different non-rigid analysis approaches have successfully been applied to 16O water resulting in a self-consistent set of transitions and energy levels to high J which allowed the spectrum to be modeled to experimental precision. The data set for 17O and 18O water was previously reviewed and many of the problematic measurements identified, but Hamiltonian modeling of the remaining data resulted in significantly poorer quality fits than that for the 16O parent. As a result, we have made additional microwave measurements and modeled the existing 17O and 18O data sets with an Euler series model. This effort has illuminated a number of additional problematic measurements in the previous data sets and has resulted in analyses of 17O and 18O water that are of similar quality to the 16O analysis. We report the new lines, the analyses and make recommendations on the quality of the experimental data sets. SS. Yu, J.C. Pearson, B.J. Drouin et al. J. Mol. Spectrosc. 279,~16-25 (2012) J. Tennyson, P.F. Bernath, L.R. Brown et al. J. Quant. Spectrosc. Rad. Trans. 117, 29-58 (2013) J. Tennyson, P.F. Bernath, L.R. Brown et al. J. Quant. Spectrosc. Rad. Trans. 110, 573-596 (2009) H.M. Pickett, J.C. Pearson, C.E. Miller J. Mol. Spectrosc. 233, 174-179 (2005)

Chemical analyses of water samples from the Picher mining area, northeast Oklahoma and southeast Kansas

USGS Publications Warehouse

Parkhurst, David L.

1987-01-01

Chemical analyses are presented for 169 water samples from Tar Creek drainage and the Picher lead-zinc mining area of northeast Oklahoma and southeast Kansas. Water samples were taken from November 1983 through February 1986 from the abandoned mines, from points of mine-water discharge, and from surface-water locations upstream and downstream from mine discharge area. The pH, temperature, alkalinity, dissolved oxygen, and specific conductance were measured in the field. Laboratory analyses routinely included the major ions plus aluminum, cadmium, copper, iron, lead, manganese, nickel, and zinc. Non-routine analyses of dissolved gases and tritium are presented. Stable carbon-isotope ratios for 11 mine-water samples and three carbonate-rock samples are reported. Miscellaneous stream-discharge measurements made at the time of sampling or taken from gaging-station records are included in the report.

MIXTURES OF THYROID DISRUPTING CHEMICALS: TESTING ADDITIVITY OF HEPATIC INDUCERS AND THYROID PEROXIDASE INHIBITORS.

EPA Science Inventory

Humans are exposed to chemical mixtures via diet, occupation, and the environment. Previous data demonstrated that low doses of polycyclic halogenated aromatic hydrocarbons (PHAHs) acting through similar mechanisms result in an additive reduction of thyroxine (T4). If xenobioti...

Chemical characteristic and functional properties of arenga starch-taro (Colocasia esculanta L.) flour noodle with turmeric extracts addition

NASA Astrophysics Data System (ADS)

Ervika Rahayu N., H.; Ariani, Dini; Miftakhussolikhah, E., Maharani P.; Yudi, P.

2017-01-01

Arenga starch-taro (Colocasia esculanta L.) flour noodle is an alternative carbohydrate source made from 75% arenga starch and 25% taro flour, but it has a different color with commercial noodle product. The addition of natural color from turmeric may change the consumer preference and affect chemical characteristic and functional properties of noodle. This research aims to identify chemical characteristic and functional properties of arenga starch-taro flour noodle with turmeric extract addition. Extraction was performed using 5 variances of turmeric rhizome (0.06; 0.12; 0.18; 0.24; and 0.30 g (fresh weight/ml water). Then, noodle was made and chemical characteristic (proximate analysis) as well as functional properties (amylose, resistant starch, dietary fiber, antioxidant activity) were then evaluated. The result showed that addition of turmeric extract did not change protein, fat, carbohydrate, amylose, and resistant starch content significantly, while antioxidant activity was increased (23,41%) with addition of turmeric extract.

Testing for Additivity in Chemical Mixtures Using a Fixed-Ratio Ray Design and Statistical Equivalence Testing Methods

EPA Science Inventory

Fixed-ratio ray designs have been used for detecting and characterizing interactions of large numbers of chemicals in combination. Single chemical dose-response data are used to predict an “additivity curve” along an environmentally relevant ray. A “mixture curve” is estimated fr...

ADDITIONAL STRESS AND FRACTURE MECHANICS ANALYSES OF PRESSURIZED WATER REACTOR PRESSURE VESSEL NOZZLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walter, Matthew; Yin, Shengjun; Stevens, Gary

2012-01-01

In past years, the authors have undertaken various studies of nozzles in both boiling water reactors (BWRs) and pressurized water reactors (PWRs) located in the reactor pressure vessel (RPV) adjacent to the core beltline region. Those studies described stress and fracture mechanics analyses performed to assess various RPV nozzle geometries, which were selected based on their proximity to the core beltline region, i.e., those nozzle configurations that are located close enough to the core region such that they may receive sufficient fluence prior to end-of-life (EOL) to require evaluation of embrittlement as part of the RPV analyses associated with pressure-temperaturemore » (P-T) limits. In this paper, additional stress and fracture analyses are summarized that were performed for additional PWR nozzles with the following objectives: To expand the population of PWR nozzle configurations evaluated, which was limited in the previous work to just two nozzles (one inlet and one outlet nozzle). To model and understand differences in stress results obtained for an internal pressure load case using a two-dimensional (2-D) axi-symmetric finite element model (FEM) vs. a three-dimensional (3-D) FEM for these PWR nozzles. In particular, the ovalization (stress concentration) effect of two intersecting cylinders, which is typical of RPV nozzle configurations, was investigated. To investigate the applicability of previously recommended linear elastic fracture mechanics (LEFM) hand solutions for calculating the Mode I stress intensity factor for a postulated nozzle corner crack for pressure loading for these PWR nozzles. These analyses were performed to further expand earlier work completed to support potential revision and refinement of Title 10 to the U.S. Code of Federal Regulations (CFR), Part 50, Appendix G, Fracture Toughness Requirements, and are intended to supplement similar evaluation of nozzles presented at the 2008, 2009, and 2011 Pressure Vessels and Piping (PVP

Chemical analyses of micrometre-sized solids by a miniature laser ablation/ionisation mass spectrometer (LMS)

NASA Astrophysics Data System (ADS)

Tulej, Marek; Wiesendanger, Reto; Neuland, Maike; Meyer, Stefan; Wurz, Peter; Neubeck, Anna; Ivarsson, Magnus; Riedo, Valentine; Moreno-Garcia, Pavel; Riedo, Andreas; Knopp, Gregor

2017-04-01

Investigation of elemental and isotope compositions of planetary solids with high spatial resolution are of considerable interest to current space research. Planetary materials are typically highly heterogenous and such studies can deliver detailed chemical information of individual sample components with the sizes down to a few micrometres. The results of such investigations can yield mineralogical surface context including mineralogy of individual grains or the elemental composition of of other objects embedded in the sample surface such as micro-sized fossils. The identification of bio-relevant material can follow by the detection of bio-relevant elements and their isotope fractionation effects [1, 2]. For chemical analysis of heterogenous solid surfaces we have combined a miniature laser ablation mass spectrometer (LMS) (mass resolution (m/Dm) 400-600; dynamic range 105-108) with in situ microscope-camera system (spatial resolution ˜2um, depth 10 um). The microscope helps to find the micrometre-sized solids across the surface sample for the direct mass spectrometric analysis by the LMS instrument. The LMS instrument combines an fs-laser ion source and a miniature reflectron-type time-of-flight mass spectrometer. The mass spectrometric analysis of the selected on the sample surface objects followed after ablation, atomisation and ionisation of the sample by a focussed laser radiation (775 nm, 180 fs, 1 kHz; the spot size of ˜20 um) [4, 5, 6]. Mass spectra of almost all elements (isotopes) present in the investigated location are measured instantaneously. A number of heterogenous rock samples containing micrometre-sized fossils and mineralogical grains were investigated with high selectivity and sensitivity. Chemical analyses of filamentous structures observed in carbonate veins (in harzburgite) and amygdales in pillow basalt lava can be well characterised chemically yielding elemental and isotope composition of these objects [7, 8]. The investigation can be

Additive mixture effects of estrogenic chemicals in human cell-based assays can be influenced by inclusion of chemicals with differing effect profiles.

PubMed

Evans, Richard Mark; Scholze, Martin; Kortenkamp, Andreas

2012-01-01

A growing body of experimental evidence indicates that the in vitro effects of mixtures of estrogenic chemicals can be well predicted from the estrogenicity of their components by the concentration addition (CA) concept. However, some studies have observed small deviations from CA. Factors affecting the presence or observation of deviations could include: the type of chemical tested; number of mixture components; mixture design; and assay choice. We designed mixture experiments that address these factors, using mixtures with high numbers of components, chemicals from diverse chemical groups, assays with different in vitro endpoints and different mixture designs and ratios. Firstly, the effects of mixtures composed of up to 17 estrogenic chemicals were examined using estrogenicity assays with reporter-gene (ERLUX) and cell proliferation (ESCREEN) endpoints. Two mixture designs were used: 1) a 'balanced' design with components present in proportion to a common effect concentration (e.g. an EC(10)) and 2) a 'non-balanced' design with components in proportion to potential human tissue concentrations. Secondly, the individual and simultaneous ability of 16 potential modulator chemicals (each with minimal estrogenicity) to influence the assay outcome produced by a reference mixture of estrogenic chemicals was examined. Test chemicals included plasticizers, phthalates, metals, PCBs, phytoestrogens, PAHs, heterocyclic amines, antioxidants, UV filters, musks, PBDEs and parabens. In all the scenarios tested, the CA concept provided a good prediction of mixture effects. Modulation studies revealed that chemicals possessing minimal estrogenicity themselves could reduce (negatively modulate) the effect of a mixture of estrogenic chemicals. Whether the type of modulation we observed occurs in practice most likely depends on the chemical concentrations involved, and better information is required on likely human tissue concentrations of estrogens and of potential modulators

Additive Mixture Effects of Estrogenic Chemicals in Human Cell-Based Assays Can Be Influenced by Inclusion of Chemicals with Differing Effect Profiles

PubMed Central

Evans, Richard Mark; Scholze, Martin; Kortenkamp, Andreas

2012-01-01

A growing body of experimental evidence indicates that the in vitro effects of mixtures of estrogenic chemicals can be well predicted from the estrogenicity of their components by the concentration addition (CA) concept. However, some studies have observed small deviations from CA. Factors affecting the presence or observation of deviations could include: the type of chemical tested; number of mixture components; mixture design; and assay choice. We designed mixture experiments that address these factors, using mixtures with high numbers of components, chemicals from diverse chemical groups, assays with different in vitro endpoints and different mixture designs and ratios. Firstly, the effects of mixtures composed of up to 17 estrogenic chemicals were examined using estrogenicity assays with reporter-gene (ERLUX) and cell proliferation (ESCREEN) endpoints. Two mixture designs were used: 1) a ‘balanced’ design with components present in proportion to a common effect concentration (e.g. an EC10) and 2) a ‘non-balanced’ design with components in proportion to potential human tissue concentrations. Secondly, the individual and simultaneous ability of 16 potential modulator chemicals (each with minimal estrogenicity) to influence the assay outcome produced by a reference mixture of estrogenic chemicals was examined. Test chemicals included plasticizers, phthalates, metals, PCBs, phytoestrogens, PAHs, heterocyclic amines, antioxidants, UV filters, musks, PBDEs and parabens. In all the scenarios tested, the CA concept provided a good prediction of mixture effects. Modulation studies revealed that chemicals possessing minimal estrogenicity themselves could reduce (negatively modulate) the effect of a mixture of estrogenic chemicals. Whether the type of modulation we observed occurs in practice most likely depends on the chemical concentrations involved, and better information is required on likely human tissue concentrations of estrogens and of potential modulators

MODEL OF ADDITIVE EFFECTS OF MIXTURES OF NARCOTIC CHEMICALS

EPA Science Inventory

Biological effects data with single chemicals are far more abundant than with mixtures. et, environmental exposures to chemical mixtures, for example near hazardous waste sites or nonpoint sources, are very common and using test data from single chemicals to approximate effects o...

A Four-Step and Four-Criteria Approach for Evaluating Evidence of Dose Addition in Chemical Mixture Toxicity

EPA Science Inventory

Dose addition is the most frequently-used component-based approach for predicting dose response for a mixture of toxicologically-similar chemicals and for statistical evaluation of whether the mixture response is consistent with dose additivity and therefore predictable from the ...

Finding Chemical Structures Corresponding to a Set of Coordinates in Chemical Descriptor Space.

PubMed

Miyao, Tomoyuki; Funatsu, Kimito

2017-08-01

When chemical structures are searched based on descriptor values, or descriptors are interpreted based on values, it is important that corresponding chemical structures actually exist. In order to consider the existence of chemical structures located in a specific region in the chemical space, we propose to search them inside training data domains (TDDs), which are dense areas of a training dataset in the chemical space. We investigated TDDs' features using diverse and local datasets, assuming that GDB11 is the chemical universe. These two analyses showed that considering TDDs gives higher chance of finding chemical structures than a random search-based method, and that novel chemical structures actually exist inside TDDs. In addition to those findings, we tested the hypothesis that chemical structures were distributed on the limited areas of chemical space. This hypothesis was confirmed by the fact that distances among chemical structures in several descriptor spaces were much shorter than those among randomly generated coordinates in the training data range. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of Natural Mineral Additives in Construction

NASA Astrophysics Data System (ADS)

Linek, Malgorzata; Nita, Piotr; Wolka, Paweł; Zebrowski, Wojciech

2017-12-01

The article concerns the idea of using selected mineral additives in the pavement quality concrete composition. The basis of the research paper was the modification of cement concrete intended for airfield pavements. The application of the additives: metakaolonite and natural zeolite was suggested. Analyses included the assessment of basic physical properties of modifiers. Screening analysis, assessment of micro structure and chemical microanalysis were conducted in case of these materials. The influence of the applied additives on the change of concrete mix parameters was also presented. The impact of zeolite and metakaolinite on the mix density, oxygen content and consistency class was analysed. The influence of modifiers on physical and mechanical changes of the hardened cement concrete was discussed (concrete density, compressive strength and bending strength during fracturing) in diversified research periods. The impact of the applied additives on the changes of internal structure of cement concrete was discussed. Observation of concrete micro structure was conducted using the scanning electron microscope. According to the obtained lab test results, parameters of the applied modifiers and their influence on changes of internal structure of cement concrete are reflected in the increase of mechanical properties of pavement quality concrete. The increase of compressive and bending strength in case of all analysed research periods was proved.

Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling

PubMed Central

Mao, Bing; Mao, Rong; Zeng, De-Hui

2017-01-01

Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling. PMID:28686660

Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling.

PubMed

Mao, Bing; Mao, Rong; Zeng, De-Hui

2017-01-01

Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling.

Chemical Analyses of Ground Water in the Carson Desert near Stillwater, Churchill County, Nevada, 2005

USGS Publications Warehouse

Fosbury, DeEtta; Walker, Mark; Stillings, Lisa L.

2008-01-01

This report presents the chemical analyses of ground-water samples collected in 2005 from domestic wells located in the Stillwater area of the Carson Desert (fig. 1). These data were evaluated for evidence of mixing with nearby geothermal waters (Fosbury, 2007). That study used several methods to identify mixing zones of ground and geothermal waters using trace elements, chemical equilibria, water temperature, geothermometer estimates, and statistical techniques. In some regions, geothermal sources influence the chemical quality of ground water used for drinking water supplies. Typical geothermal contaminants include arsenic, mercury, antimony, selenium, thallium, boron, lithium, and fluoride (Webster and Nordstrom, 2003). The Environmental Protection Agency has established primary drinking water standards for these, with the exception of boron and lithium. Concentrations of some trace metals in geothermal water may exceed drinking water standards by several orders of magnitude. Geothermal influences on water quality are likely to be localized, depending on directions of ground water flow, the relative volumes of geothermal sources and ground water originating from other sources, and depth below the surface from which water is withdrawn. It is important to understand the areal extent of shallow mixing of geothermal water because it may have adverse chemical and aesthetic effects on domestic drinking water. It would be useful to understand the areal extent of these effects.

ADDITIVITY ASSESSMENT OF TRIHALOMETHANE MIXTURES BY PROPORTIONAL RESPONSE ADDITION

EPA Science Inventory

If additivity is known or assumed, the toxicity of a chemical mixture may be predicted from the dose response curves of the individual chemicals comprising the mixture. As single chemical data are abundant and mixture data sparse, mixture risk methods that utilize single chemical...

Occupational allergic contact dermatitis caused by sterile non-latex protective gloves: clinical investigation and chemical analyses.

PubMed

Pontén, Ann; Hamnerius, Nils; Bruze, Magnus; Hansson, Christer; Persson, Christina; Svedman, Cecilia; Thörneby Andersson, Kirsten; Bergendorff, Ola

2013-02-01

An increased frequency of occupational contact hand dermatitis among surgical operating theatre personnel has been noticed. To evaluate patients with occupational contact dermatitis caused by their rubber gloves, and to describe a method for analysing the content of the allergens in the gloves. Patch tests were performed with the baseline series, a rubber chemical series, and the patients' own gloves. A method for analysing 1,3-diphenylguanidine (DPG) and cetylpyridinium chloride in the gloves was developed. Contact allergy to thiuram mix was found in 8 of 16 patients, whereas 12 of 16 patients reacted to DPG. In 7 of 8 patients, contact allergy to cetylpyridinium chloride was found. In the patients' gloves, cetylpyridinium chloride and DPG were detected at higher concentrations on the inside of the gloves than on the outside. Most patients had worked for decades in their present occupations, but their hand dermatitis had only been present for months. Contact allergy to DPG in gloves has been disputed, but, in this study, we were able to confirm the presence of DPG and cetylpyridinium chloride in the causative gloves by using a modified method for the analysis. The presence of these chemicals in gloves caused an increase in occupational contact dermatitis in surgical operating theatre personnel. © 2012 John Wiley & Sons A/S.

Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses

NASA Astrophysics Data System (ADS)

Dou, Xiaolin; He, Ping; Cheng, Xiaoli; Zhou, Wei

2016-01-01

Quantification of dynamics of soil organic carbon (SOC) pools under the influence of long-term fertilization is essential for predicting carbon (C) sequestration. We combined soil chemical fractionation with stable C isotope analyses to investigate the C dynamics of the various SOC pools after 25 years of fertilization. Five types of soil samples (0-20, 20-40 cm) including the initial level (CK) and four fertilization treatments (inorganic nitrogen fertilizer, IN; balanced inorganic fertilizer, NPK; inorganic fertilizer plus farmyard manure, MNPK; inorganic fertilizer plus corn straw residue, SNPK) were separated into recalcitrant and labile fractions, and the fractions were analysed for C content, C:N ratios, δ13C values, soil C and N recalcitrance indexes (RIC and RIN). Chemical fractionation showed long-term MNPK fertilization strongly increased the SOC storage in both soil layers (0-20 cm = 1492.4 gC m2 and 20-40 cm = 1770.6 gC m2) because of enhanced recalcitrant C (RC) and labile C (LC). The 25 years of inorganic fertilizer treatment did not increase the SOC storage mainly because of the offsetting effects of enhanced RC and decreased LC, whereas no clear SOC increases under the SNPK fertilization resulted from the fast decay rates of soil C.

Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses.

PubMed

Dou, Xiaolin; He, Ping; Cheng, Xiaoli; Zhou, Wei

2016-01-11

Quantification of dynamics of soil organic carbon (SOC) pools under the influence of long-term fertilization is essential for predicting carbon (C) sequestration. We combined soil chemical fractionation with stable C isotope analyses to investigate the C dynamics of the various SOC pools after 25 years of fertilization. Five types of soil samples (0-20, 20-40 cm) including the initial level (CK) and four fertilization treatments (inorganic nitrogen fertilizer, IN; balanced inorganic fertilizer, NPK; inorganic fertilizer plus farmyard manure, MNPK; inorganic fertilizer plus corn straw residue, SNPK) were separated into recalcitrant and labile fractions, and the fractions were analysed for C content, C:N ratios, δ(13)C values, soil C and N recalcitrance indexes (RIC and RIN). Chemical fractionation showed long-term MNPK fertilization strongly increased the SOC storage in both soil layers (0-20 cm = 1492.4 gC m(2) and 20-40 cm = 1770.6 gC m(2)) because of enhanced recalcitrant C (RC) and labile C (LC). The 25 years of inorganic fertilizer treatment did not increase the SOC storage mainly because of the offsetting effects of enhanced RC and decreased LC, whereas no clear SOC increases under the SNPK fertilization resulted from the fast decay rates of soil C.

Chemical stabilization of polymers: Implications for dermal exposure to additives.

PubMed

Bartsch, N; Girard, M; Schneider, L; Weijgert, V Van De; Wilde, A; Kappenstein, O; Vieth, B; Hutzler, C; Luch, A

2018-04-16

distinct skin layers was demonstrated. This is exemplified by the penetration of the procarcinogenic antioxidant N-phenylnaphthalen-2-amine (Neozon D) into the viable epidermis and the permeation through the skin of the neurotoxic plasticizer N-butylbenzenesulfonamide (NBBS). In addition, the analyses of additive degradation products in the isolated skin layers revealed the presence of 2-tert-butyl-4-methylphenol in all layers after contact to a polymer with substances of origin like Antioxidant 2246. Thus, attention needs to be paid to absorption of polymer additives together with their degradation products when it comes to dermal exposure assessment.

Operando Multi-modal Synchrotron Investigation for Structural and Chemical Evolution of Cupric Sulfide (CuS) Additive in Li-S battery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Ke; Zhao, Chonghang; Lin, Cheng-Hung

Conductive metal sulfides are promising multi-functional additives for future lithium-sulfur (Li-S) batteries. These can increase the sulfur cathode’s electrical conductivity to improve the battery’s power capability, as well as contribute to the overall cell-discharge capacity. This multi-functional electrode design showed initial promise; however, complicated interactions at the system level are accompanied by some detrimental side effects. The metal sulfide additives with a chemical conversion as the reaction mechanism, e.g., CuS and FeS 2, can increase the theoretical capacity of the Li-S system. However, these additives may cause undesired parasitic reactions, such as the dissolution of the additive in the electrolyte.more » Studying such complex reactions presents a challenge because it requires experimental methods that can track the chemical and structural evolution of the system during an electrochemical process. To address the fundamental mechanisms in these systems, we employed an operando multimodal x-ray characterization approach to study the structural and chemical evolution of the metal sulfide—utilizing powder diffraction and fluorescence imaging to resolve the former and absorption spectroscopy the latter—during lithiation and de-lithiation of a Li-S battery with CuS as the multi-functional cathode additive. The resulting elucidation of the structural and chemical evolution of the system leads to a new description of the reaction mechanism.« less

Operando Multi-modal Synchrotron Investigation for Structural and Chemical Evolution of Cupric Sulfide (CuS) Additive in Li-S battery

DOE PAGES

Sun, Ke; Zhao, Chonghang; Lin, Cheng-Hung; ...

2017-10-11

Conductive metal sulfides are promising multi-functional additives for future lithium-sulfur (Li-S) batteries. These can increase the sulfur cathode’s electrical conductivity to improve the battery’s power capability, as well as contribute to the overall cell-discharge capacity. This multi-functional electrode design showed initial promise; however, complicated interactions at the system level are accompanied by some detrimental side effects. The metal sulfide additives with a chemical conversion as the reaction mechanism, e.g., CuS and FeS 2, can increase the theoretical capacity of the Li-S system. However, these additives may cause undesired parasitic reactions, such as the dissolution of the additive in the electrolyte.more » Studying such complex reactions presents a challenge because it requires experimental methods that can track the chemical and structural evolution of the system during an electrochemical process. To address the fundamental mechanisms in these systems, we employed an operando multimodal x-ray characterization approach to study the structural and chemical evolution of the metal sulfide—utilizing powder diffraction and fluorescence imaging to resolve the former and absorption spectroscopy the latter—during lithiation and de-lithiation of a Li-S battery with CuS as the multi-functional cathode additive. The resulting elucidation of the structural and chemical evolution of the system leads to a new description of the reaction mechanism.« less

Metal and physico-chemical variations at a hydroelectric reservoir analyzed by Multivariate Analyses and Artificial Neural Networks: environmental management and policy/decision-making tools.

PubMed

Cavalcante, Y L; Hauser-Davis, R A; Saraiva, A C F; Brandão, I L S; Oliveira, T F; Silveira, A M

2013-01-01

This paper compared and evaluated seasonal variations in physico-chemical parameters and metals at a hydroelectric power station reservoir by applying Multivariate Analyses and Artificial Neural Networks (ANN) statistical techniques. A Factor Analysis was used to reduce the number of variables: the first factor was composed of elements Ca, K, Mg and Na, and the second by Chemical Oxygen Demand. The ANN showed 100% correct classifications in training and validation samples. Physico-chemical analyses showed that water pH values were not statistically different between the dry and rainy seasons, while temperature, conductivity, alkalinity, ammonia and DO were higher in the dry period. TSS, hardness and COD, on the other hand, were higher during the rainy season. The statistical analyses showed that Ca, K, Mg and Na are directly connected to the Chemical Oxygen Demand, which indicates a possibility of their input into the reservoir system by domestic sewage and agricultural run-offs. These statistical applications, thus, are also relevant in cases of environmental management and policy decision-making processes, to identify which factors should be further studied and/or modified to recover degraded or contaminated water bodies. Copyright © 2012 Elsevier B.V. All rights reserved.

Additional and revised thermochemical data and computer code for WATEQ2: a computerized chemical model for trace and major element speciation and mineral equilibria of natural waters

USGS Publications Warehouse

Ball, James W.; Nordstrom, D. Kirk; Jenne, Everett A.

1980-01-01

A computerized chemical model, WATEQ2, has resulted from extensive additions to and revision of the WATEQ model of Truesdell and Jones (Truesdell, A. H., and Jones, B. F., 1974, WATEQ, a computer program for calculating chemical equilibria of natural waters: J. Res. U. S. Geol, Survey, v. 2, p. 233-274). The model building effort has necessitated searching the literature and selecting thermochemical data pertinent to the reactions added to the model. This supplementary report manes available the details of the reactions added to the model together with the selected thermochemical data and their sources. Also listed are details of program operation and a brief description of the output of the model. Appendices-contain a glossary of identifiers used in the PL/1 computer code, the complete PL/1 listing, and sample output from three water analyses used as test cases.

Detection and characterisation of frauds in bovine meat in natura by non-meat ingredient additions using data fusion of chemical parameters and ATR-FTIR spectroscopy.

PubMed

Nunes, Karen M; Andrade, Marcus Vinícius O; Santos Filho, Antônio M P; Lasmar, Marcelo C; Sena, Marcelo M

2016-08-15

Concerns about meat authenticity are increasing recently, due to great fraud scandals. This paper analysed real samples (43 adulterated and 12 controls) originated from criminal networks dismantled by the Brazilian Police. This fraud consisted of injecting solutions of non-meat ingredients (NaCl, phosphates, carrageenan, maltodextrin) in bovine meat, aiming to increase its water holding capacity. Five physico-chemical variables were determined, protein, ash, chloride, sodium, phosphate. Additionally, infrared spectra were recorded. Supervised classification PLS-DA models were built with each data set individually, but the best model was obtained with data fusion, correctly detecting 91% of the adulterated samples. From this model, a variable selection based on the highest VIPscores was performed and a new data fusion model was built with only one chemical variable, providing slightly lower predictions, but a good cost/performance ratio. Finally, some of the selected infrared bands were specifically associated to the presence of adulterants NaCl, tripolyphosphate and carrageenan. Copyright © 2016 Elsevier Ltd. All rights reserved.

An alpha particle instrument with alpha, proton, and X-ray modes for planetary chemical analyses

NASA Technical Reports Server (NTRS)

Economou, T. E.; Turkevich, A. L.

1976-01-01

The interaction of alpha particles with matter is employed in a compact instrument that could provide rather complete in-situ chemical analyses of surfaces and thin atmospheres of extraterrestrial bodies. The instrument is a miniaturized and improved version of the Surveyor lunar instrument. The backscattering of alpha particles and (alpha, p) reactions provide analytical data on the light elements (carbon-iron). An X-ray mode that detects the photons produced by the alpha sources provides sensitivity and resolution for the chemical elements heavier than about silicon. The X-rays are detected by semiconductor detectors having a resolution between 150 and 250 eV at 5.9 keV. Such an instrument can identify and determine with good accuracy 99 percent of the atoms (except hydrogen) in rocks. For many trace elements, the detecting sensitivity is a few ppm. Auxiliary sources could be used to enhance the sensitivities for elements of special interest. The instrument could probably withstand the acceleration involved in semi-hard landings.

Chemical analyses of ground water for saline-water resources studies in Texas Coastal Plain stored in National Water Data Storage and Retrieval System

USGS Publications Warehouse

Taylor, R.E.

1975-01-01

Chemical analyses of 4,269 water samples from wells in 66 counties in Texas have been processed into the National Water Data Storage and Retrieval System by the Gulf Coast Hydrogeology Project of the U. S. Geological Survey. More than 65,000 chemical analyses of saline waters produced by oil test and production wells have been contributed to the project by major oil companies. The computerized tabulation and the computer-drawn map of the locations of sampling sites are the initial release of oil company, State, and Federal data in Texas Coastal Plain from the data bank.

Intramolecular hydrogen-bond activation for the addition of nucleophilic imines: 2-hydroxybenzophenone as a chemical auxiliary.

PubMed

Choubane, Houcine; Garrido-Castro, Alberto F; Alvarado, Cuauhtemoc; Martín-Somer, Ana; Guerrero-Corella, Andrea; Daaou, Mortada; Díaz-Tendero, Sergio; Carmen Maestro, M; Fraile, Alberto; Alemán, José

2018-03-29

The addition of nucleophilic imines, using 2-hydroxybenzophenone as a chemical auxiliary, is presented. An intramolecular six-membered ring via hydrogen bonding that enhances the reactivity and selectivity is the key of this strategy, which is supported by DFT calculations and experimental trials.

Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses

PubMed Central

Dou, Xiaolin; He, Ping; Cheng, Xiaoli; Zhou, Wei

2016-01-01

Quantification of dynamics of soil organic carbon (SOC) pools under the influence of long-term fertilization is essential for predicting carbon (C) sequestration. We combined soil chemical fractionation with stable C isotope analyses to investigate the C dynamics of the various SOC pools after 25 years of fertilization. Five types of soil samples (0–20, 20–40 cm) including the initial level (CK) and four fertilization treatments (inorganic nitrogen fertilizer, IN; balanced inorganic fertilizer, NPK; inorganic fertilizer plus farmyard manure, MNPK; inorganic fertilizer plus corn straw residue, SNPK) were separated into recalcitrant and labile fractions, and the fractions were analysed for C content, C:N ratios, δ13C values, soil C and N recalcitrance indexes (RIC and RIN). Chemical fractionation showed long-term MNPK fertilization strongly increased the SOC storage in both soil layers (0–20 cm = 1492.4 gC m2 and 20–40 cm = 1770.6 gC m2) because of enhanced recalcitrant C (RC) and labile C (LC). The 25 years of inorganic fertilizer treatment did not increase the SOC storage mainly because of the offsetting effects of enhanced RC and decreased LC, whereas no clear SOC increases under the SNPK fertilization resulted from the fast decay rates of soil C. PMID:26750143

Chemical Sensing for Buried Landmines - Fundamental Processes Influencing Trace Chemical Detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

PHELAN, JAMES M.

2002-05-01

Mine detection dogs have a demonstrated capability to locate hidden objects by trace chemical detection. Because of this capability, demining activities frequently employ mine detection dogs to locate individual buried landmines or for area reduction. The conditions appropriate for use of mine detection dogs are only beginning to emerge through diligent research that combines dog selection/training, the environmental conditions that impact landmine signature chemical vapors, and vapor sensing performance capability and reliability. This report seeks to address the fundamental soil-chemical interactions, driven by local weather history, that influence the availability of chemical for trace chemical detection. The processes evaluated include:more » landmine chemical emissions to the soil, chemical distribution in soils, chemical degradation in soils, and weather and chemical transport in soils. Simulation modeling is presented as a method to evaluate the complex interdependencies among these various processes and to establish conditions appropriate for trace chemical detection. Results from chemical analyses on soil samples obtained adjacent to landmines are presented and demonstrate the ultra-trace nature of these residues. Lastly, initial measurements of the vapor sensing performance of mine detection dogs demonstrates the extreme sensitivity of dogs in sensing landmine signature chemicals; however, reliability at these ultra-trace vapor concentrations still needs to be determined. Through this compilation, additional work is suggested that will fill in data gaps to improve the utility of trace chemical detection.« less

Chemical analyses in the World Coal Quality Inventory

USGS Publications Warehouse

Tewalt, Susan J.; Belkin, Harvey E.; SanFilipo, John R.; Merrill, Matthew D.; Palmer, Curtis A.; Warwick, Peter D.; Karlsen, Alexander W.; Finkelman, Robert B.; Park, Andy J.

2010-01-01

The main objective of the World Coal Quality Inventory (WoCQI) was to collect and analyze a global set of samples of mined coal during a time period from about 1995 to 2006 (Finkelman and Lovern, 2001). Coal samples were collected by foreign collaborators and submitted to country specialists in the U.S. Geological Survey (USGS) Energy Program. However, samples from certain countries, such as Afghanistan, India, and Kyrgyzstan, were collected collaboratively in the field with USGS personnel. Samples were subsequently analyzed at two laboratories: the USGS Inorganic Geochemistry Laboratory located in Denver, CO and a commercial laboratory (Geochemical Testing, Inc.) located in Somerset, PA. Thus the dataset, which is in Excel (2003) format and includes 1,580 samples from 57 countries, does not have the inter-laboratory variability that is present in many compilations. Major-, minor-, and trace-element analyses from the USGS laboratory, calculated to a consistent analytical basis (dry, whole-coal) and presented with available sample identification information, are sorted alphabetically by country name. About 70 percent of the samples also have data from the commercial laboratory, which are presented on an as-received analytical basis. The USGS initiated a laboratory review of quality assurance in 2008, covering quality control and methodology used in inorganic chemical analyses of coal, coal power plant ash, water, and sediment samples. This quality control review found that data generated by the USGS Inorganic Geochemistry Laboratory from 1996 through 2006 were characterized by quality practices that did not meet USGS requirements commonly in use at the time. The most serious shortcomings were (1) the adjustment of raw sample data to standards when the instrument values for those standards exceeded acceptable limits or (2) the insufficient use of multiple standards to provide adequate quality assurance. In general, adjustment of raw data to account for instrument

Nature and prevalence of non-additive toxic effects in industrially relevant mixtures of organic chemicals.

PubMed

Parvez, Shahid; Venkataraman, Chandra; Mukherji, Suparna

2009-06-01

The concentration addition (CA) and the independent action (IA) models are widely used for predicting mixture toxicity based on its composition and individual component dose-response profiles. However, the prediction based on these models may be inaccurate due to interaction among mixture components. In this work, the nature and prevalence of non-additive effects were explored for binary, ternary and quaternary mixtures composed of hydrophobic organic compounds (HOCs). The toxicity of each individual component and mixture was determined using the Vibrio fischeri bioluminescence inhibition assay. For each combination of chemicals specified by the 2(n) factorial design, the percent deviation of the predicted toxic effect from the measured value was used to characterize mixtures as synergistic (positive deviation) and antagonistic (negative deviation). An arbitrary classification scheme was proposed based on the magnitude of deviation (d) as: additive (< or =10%, class-I) and moderately (10< d < or =30 %, class-II), highly (30< d < or =50%, class-III) and very highly (>50%, class-IV) antagonistic/synergistic. Naphthalene, n-butanol, o-xylene, catechol and p-cresol led to synergism in mixtures while 1, 2, 4-trimethylbenzene and 1, 3-dimethylnaphthalene contributed to antagonism. Most of the mixtures depicted additive or antagonistic effect. Synergism was prominent in some of the mixtures, such as, pulp and paper, textile dyes, and a mixture composed of polynuclear aromatic hydrocarbons. The organic chemical industry mixture depicted the highest abundance of antagonism and least synergism. Mixture toxicity was found to depend on partition coefficient, molecular connectivity index and relative concentration of the components.

Additives

NASA Technical Reports Server (NTRS)

Smalheer, C. V.

1973-01-01

The chemistry of lubricant additives is discussed to show what the additives are chemically and what functions they perform in the lubrication of various kinds of equipment. Current theories regarding the mode of action of lubricant additives are presented. The additive groups discussed include the following: (1) detergents and dispersants, (2) corrosion inhibitors, (3) antioxidants, (4) viscosity index improvers, (5) pour point depressants, and (6) antifouling agents.

Halogenation of Hydraulic Fracturing Additives in the Shale Well Parameter Space

NASA Astrophysics Data System (ADS)

Sumner, A. J.; Plata, D.

2017-12-01

Horizontal Drilling and Hydraulic fracturing (HDHF) involves the deep-well injection of a `fracking fluid' composed of diverse and numerous chemical additives designed to facilitate the release and collection of natural gas from shale plays. The potential impacts of HDHF operations on water resources and ecosystems are numerous, and analyses of flowback samples revealed organic compounds from both geogenic and anthropogenic sources. Furthermore, halogenated chemicals were also detected, and these compounds are rarely disclosed, suggesting the in situ halogenation of reactive additives. To test this transformation hypothesis, we designed and operated a novel high pressure and temperature reactor system to simulate the shale well parameter space and investigate the chemical reactivity of twelve commonly disclosed and functionally diverse HDHF additives. Early results revealed an unanticipated halogenation pathway of α-β unsaturated aldehyde, Cinnamaldehyde, in the presence of oxidant and concentrated brine. Ongoing experiments over a range of parameters informed a proposed mechanism, demonstrating the role of various shale-well specific parameters in enabling the demonstrated halogenation pathway. Ultimately, these results will inform a host of potentially unintended interactions of HDHF additives during the extreme conditions down-bore of a shale well during HDHF activities.

Landfill mining: Resource potential of Austrian landfills--Evaluation and quality assessment of recovered municipal solid waste by chemical analyses.

PubMed

Wolfsberger, Tanja; Aldrian, Alexia; Sarc, Renato; Hermann, Robert; Höllen, Daniel; Budischowsky, Andreas; Zöscher, Andreas; Ragoßnig, Arne; Pomberger, Roland

2015-11-01

Since the need for raw materials in countries undergoing industrialisation (like China) is rising, the availability of metal and fossil fuel energy resources (like ores or coal) has changed in recent years. Landfill sites can contain considerable amounts of recyclables and energy-recoverable materials, therefore, landfill mining is an option for exploiting dumped secondary raw materials, saving primary sources. For the purposes of this article, two sanitary landfill sites have been chosen for obtaining actual data to determine the resource potential of Austrian landfills. To evaluate how pretreating waste before disposal affects the resource potential of landfills, the first landfill site has been selected because it has received untreated waste, whereas mechanically-biologically treated waste was dumped in the second. The scope of this investigation comprised: (1) waste characterisation by sorting analyses of recovered waste; and (2) chemical analyses of specific waste fractions for quality assessment regarding potential energy recovery by using it as solid recovered fuels. The content of eight heavy metals and the net calorific values were determined for the chemical characterisation tests. © The Author(s) 2015.

Evaluation of food-relevant chemicals in the ToxCast high ...

EPA Pesticide Factsheets

There are thousands of chemicals that are directly added to or come in contact with food, many of which have undergone little to no toxicological evaluation. The ToxCast high-throughput screening (HTS) program has evaluated over 1,800 chemicals in concentration-response across ~820 assay endpoints and continues to grow; with all data completely available to the public, this resource serves as a unique opportunity to evaluate the bioactivity of chemicals in vitro. This study investigated the chemical landscape of the food-relevant chemical universe using cheminformatics analyses, and subsequently evaluated the bioactivity of food-relevant chemicals included in the ToxCast HTS program. Initially, a list of 9,437 food-relevant chemicals was compiled by comprehensively mining publicly available sources for direct food additives, food contact substances, indirect food additives, and pesticides. Of these food-relevant chemicals, 4,638 were associated with curated structure definition files amenable to defining physical/chemical features used to generate chemical fingerprints. Clustering was conducted based on the chemical fingerprints using a self-organizing map approach. This revealed that pesticides, food contact substances, and direct food additives generally clustered apart from one another, supporting that these categories reflect not only different uses but also distinct chemistries. Subsequently, 967 of the 9,437 food-relevant chemicals were identified in the T

Evaluation of Pre- and Post- Redevelopment Groundwater Chemical Analyses from LM Monitoring Wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamp, Susan; Dayvault, Jalena

This report documents the efforts and analyses conducted for the Applied Studies and Technology (AS&T) Ancillary Work Plan (AWP) project titled Evaluation of Pre- and Post- Redevelopment Groundwater Sample Laboratory Analyses from Selected LM Groundwater Monitoring Wells. This effort entailed compiling an inventory of nearly 500 previous well redevelopment events at 16 U.S. Department of Energy Office of Legacy Management (LM) sites, searching the literature for impacts of well redevelopment on groundwater sample quality, and—the focus of this report—evaluating the impacts of well redevelopment on field measurements and sample analytical results. Study Catalyst Monitoring well redevelopment, the surging or high-volumemore » pumping of a well to loosen and remove accumulated sediment and biological build-up from a well, is considered an element of monitoring well maintenance that is implemented periodically during the lifetime of the well to mitigate its gradual deterioration. Well redevelopment has been conducted fairly routinely at a few LM sites in the western United States (e.g., the Grand Junction office site and the Gunnison processing site in Colorado), but at most other sites in this region it is not a routine practice. Also, until recently (2014–2015), there had been no specific criteria for implementing well redevelopment, and documentation of redevelopment events has been inconsistent. A catalyst for this evaluation was the self-identification of these inconsistencies by the Legacy Management Support contractor. As a result, in early 2015 Environmental Monitoring Operations (EMO) staff began collecting and documenting additional field measurements during well redevelopment events. In late 2015, AS&T staff undertook an independent internal evaluation of EMO's well redevelopment records and corresponding pre- and post-well-redevelopment groundwater analytical results. Study Findings Although literature discussions parallel the prevailing industry

Dissecting the effect of chemical additives on the enzymatic hydrolysis of pretreated wheat straw.

PubMed

Monschein, Mareike; Reisinger, Christoph; Nidetzky, Bernd

2014-10-01

Chemical additives were examined for ability to increase the enzymatic hydrolysis of thermo-acidically pretreated wheat straw by Trichoderma reesei cellulase at 50 °C. Semi-empirical descriptors derived from the hydrolysis time courses were applied to compare influence of these additives on lignocellulose bioconversion on a kinetic level, presenting a novel view on their mechanism of action. Focus was on rate retardation during hydrolysis, substrate conversion and enzyme adsorption. PEG 8000 enabled a reduction of enzyme loading by 50% while retaining the same conversion of 67% after 24h. For the first time, a beneficial effect of urea is reported, increasing the final substrate conversion after 48 h by 16%. The cationic surfactant cetyl-trimethylammonium bromide (CTAB) enhanced the hydrolysis rate at extended reaction time (rlim) by 34% and reduced reaction time by 28%. A combination of PEG 8000 and urea increased sugar release more than additives used individually. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of electronegative additives on physical properties and chemical activity of gas discharge plasma

NASA Astrophysics Data System (ADS)

Kuznetsov, D. L.; Filatov, I. E.; Uvarin, V. V.

2018-01-01

Effect of electronegative additives (oxygen O2, sulfur dioxide SO2, carbon disulfide CS2, and carbon tetrachloride CCl4) on physical properties and chemical activity of plasma formed by pulsed corona discharge and by non-self-sustained discharge supported by pulsed electron beam in atmospheric pressure gas mixtures was investigated. It is shown that a decrease in discharge current depends on a sort of the additive and on its concentration. The reason is the difference in rate constants of electron attachment processes for the above molecules. In experiments on volatile organic compounds (VOCs) conversion in air by streamer corona it is obtained that an addition of CCl4 both decreases the discharge current amplitude and increases the VOCs conversion degree. An installation for investigation of electron attachment processes and for study of toxic impurities conversion in plasma formed by non-self-sustained discharge initiated by pulsed nanosecond electron beam is created.

Multivariate analyses of crater parameters and the classification of craters

NASA Technical Reports Server (NTRS)

Siegal, B. S.; Griffiths, J. C.

1974-01-01

Multivariate analyses were performed on certain linear dimensions of six genetic types of craters. A total of 320 craters, consisting of laboratory fluidization craters, craters formed by chemical and nuclear explosives, terrestrial maars and other volcanic craters, and terrestrial meteorite impact craters, authenticated and probable, were analyzed in the first data set in terms of their mean rim crest diameter, mean interior relief, rim height, and mean exterior rim width. The second data set contained an additional 91 terrestrial craters of which 19 were of experimental percussive impact and 28 of volcanic collapse origin, and which was analyzed in terms of mean rim crest diameter, mean interior relief, and rim height. Principal component analyses were performed on the six genetic types of craters. Ninety per cent of the variation in the variables can be accounted for by two components. Ninety-nine per cent of the variation in the craters formed by chemical and nuclear explosives is explained by the first component alone.

Chemical analyses of elutriates, native water, and bottom material from the Chetco, Rogue, and Columbia rivers in western Oregon

USGS Publications Warehouse

Fuhrer, Gregory J.

1984-01-01

Chemical analyses of elutriates, bottom sediment, and water samples for selected metals, nutrients and organic compounds including insecticides, herbicides, and acid/neutral extractables have been made to provide data to determine short-term water-quality conditions associated with dredging operations in rivers and estuaries. Between April and August 1982, data were collected from the Chetco and Rogue River estuaries in southwestern Oregon, and from the mouth of the Columbia River in the northwestern Oregon to Cathlamet Bay, 18.2 miles upstream. In an elutriation test, bottom materials from a potential dredge site are mixed with native water - collected from either a dredge or disposal site - and the liquid portion of the mixture is removed, filtered, and chemically analyzed. Presented in this report are chemical and physical analyses of elutriates, native water, and bottom material for selected metals, ammonia, organic carbon, pesticides, particle size, and gas chromatographic/mass spectrometric semi-quantitative organic scans. Elutriate and bottom-material samples were screened specifically for phenolic compounds, particularly the chlorinated phenols; phenol was the only compound identified. Elutriate-test results showed variability for selected trace-metal concentrations of dissolved chemicals as follows: in micrograms per liter, arsenic ranged from < 1 to 15, cadmium from 1 to 210, copper from < 1 to 13, chromium from < 1 to 5, and nickel from 2 to 18. Results of computations to determine the amount of a constituent associated with bottom material and interstitial water and subsequently released (dissolved) into the elutriate-test native-mixing water are presented for selected trace metals. The highest elutriate-test release was 35 percent for manganese; the second highest, 5 percent for cadmium. All other computed releases were less than or equal to 1 percent. (USGS)

Central Processing of the Chemical Senses: An Overview

PubMed Central

2010-01-01

Our knowledge regarding the neural processing of the three chemical senses has been considerably lagging behind that of our other senses. It is only during the last 25 years that significant advances have been made in our understanding of where in the human brain odors, tastants, and trigeminal stimuli are processed. Here, we provide an overview of the current knowledge of how the human brain processes chemical stimuli based on findings in neuroimaging studies using positron emission tomography and functional magnetic resonance imaging. Additionally, we provide new insights from recent meta-analyses, on the basis of all published neuroimaging studies of the chemical senses, of where the chemical senses converge in the brain. PMID:21503268

The effect of a chemical additive on the fermentation and aerobic stability of high-moisture corn.

PubMed

Da Silva, T C; Smith, M L; Barnard, A M; Kung, L

2015-12-01

The objective of this experiment was to evaluate the effect of a chemical additive on the fermentation and aerobic stability of high-moisture corn (HMC). Ground HMC (~63% dry matter) was untreated, or treated with an additive containing sodium benzoate, potassium sorbate, and sodium nitrite as active ingredients, at 0, 2, 3, or 4 L/t of fresh matter. Laboratory silos (7.5 L) were prepared and ensiled for 21 and 90d (4 silos/treatment per d of ensiling). Small bag silos were prepared for untreated HMC and HMC treated with 4 L/t of the additive and analyzed for nitrate-N and nitrite-N after 0, 3, and 7d of ensiling. The concentration of nitrate-N was similar between these 2 treatments and was below levels considered problematic for ruminants. Nitrite-N was greater in HMC treated with the high level of additive but was also very low for both treatments. Numbers of yeasts were similar among treatments in fresh HMC and decreased substantially after ensiling. Numbers of yeasts were similar among treatments after 21d of ensiling but after 90d they were lower in treated versus untreated HMC. Concentrations of organic acids (lactic, acetic, and propionic) and pH were not different among treatments at any time of ensiling. In contrast, treatment with the additive markedly decreased the concentration of ethanol in HMC after 21 and 90d when compared with untreated HMC. Treatment with all levels of the additive markedly improved the aerobic stability and improved the recovery of dry matter compared with untreated HMC. Overall, our findings suggest that the chemical additive used in this study has the potential to improve the fermentation and aerobic stability of HMC after a relatively short period (21d) and after a moderate length (90d) of ensiling. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Molecular phylogenetic and chemical analyses of the microbial mats in deep-sea cold seep sediments at the northeastern Japan Sea.

PubMed

Arakawa, Shizuka; Sato, Takako; Sato, Rumi; Zhang, Jing; Gamo, Toshitaka; Tsunogai, Urumu; Hirota, Akinari; Yoshida, Yasuhiko; Usami, Ron; Inagaki, Fumio; Kato, Chiaki

2006-08-01

Microbial communities inhabiting deep-sea cold seep sediments at the northeastern Japan Sea were characterized by molecular phylogenetic and chemical analyses. White patchy microbial mats were observed along the fault offshore the Hokkaido Island and sediment samples were collected from two stations at the southern foot of the Shiribeshi seamount (M1 site at a depth of 2,961 m on the active fault) and off the Motta Cape site (M2 site at a depth of 3,064 m off the active fault). The phylogenetic and terminal-restriction fragment polymorphism analyses of PCR-amplified 16S rRNA genes revealed that microbial community structures were different between two sampling stations. The members of ANME-2 archaea and diverse bacterial components including sulfate reducers within Deltaproteobacteria were detected from M1 site, indicating the occurrence of biologically mediated anaerobic oxidation of methane, while microbial community at M2 site was predominantly composed of members of Marine Crenarchaeota group I, sulfate reducers of Deltaproteobacteria, and sulfur oxidizers of Epsilonproteobacteria. Chemical analyses of seawater above microbial mats suggested that concentrations of sulfate and methane at M1 site were largely decreased relative to those at M2 site and carbon isotopic composition of methane at M1 site shifted heavier ((13)C-enriched), the results of which are consistent with molecular analyses. These results suggest that the mat microbial communities in deep-sea cold seep sediments at the northeastern Japan Sea are significantly responsible for sulfur and carbon circulations and the geological activity associated with plate movements serves unique microbial habitats in deep-sea environments.

Chemical Analyses of Wasp-Associated Streptomyces Bacteria Reveal a Prolific Potential for Natural Products Discovery

PubMed Central

Clardy, Jon; Currie, Cameron R.

2011-01-01

Identifying new sources for small molecule discovery is necessary to help mitigate the continuous emergence of antibiotic-resistance in pathogenic microbes. Recent studies indicate that one potentially rich source of novel natural products is Actinobacterial symbionts associated with social and solitary Hymenoptera. Here we test this possibility by examining two species of solitary mud dauber wasps, Sceliphron caementarium and Chalybion californicum. We performed enrichment isolations from 33 wasps and obtained more than 200 isolates of Streptomyces Actinobacteria. Chemical analyses of 15 of these isolates identified 11 distinct and structurally diverse secondary metabolites, including a novel polyunsaturated and polyoxygenated macrocyclic lactam, which we name sceliphrolactam. By pairing the 15 Streptomyces strains against a collection of fungi and bacteria, we document their antifungal and antibacterial activity. The prevalence and anti-microbial properties of Actinobacteria associated with these two solitary wasp species suggest the potential role of these Streptomyces as antibiotic-producing symbionts, potentially helping defend their wasp hosts from pathogenic microbes. Finding phylogenetically diverse and chemically prolific Actinobacteria from solitary wasps suggests that insect-associated Actinobacteria can provide a valuable source of novel natural products of pharmaceutical interest. PMID:21364940

Joint effects of heterogeneous estrogenic chemicals in the E-screen--exploring the applicability of concentration addition.

PubMed

Silva, Elisabete; Rajapakse, Nissanka; Scholze, Martin; Backhaus, Thomas; Ermler, Sibylle; Kortenkamp, Andreas

2011-08-01

In the last few years, significant advances have been made toward understanding the joint action of endocrine disrupting chemicals (EDCs). A number of studies have demonstrated that the combined effects of different types of EDCs (e.g., estrogenic, antiandrogenic, or thyroid-disrupting agents) can be predicted by the model of concentration addition (CA). However, there is still limited information on the effects of mixtures of large numbers of chemicals with varied structural features, which are more representative of realistic human exposure scenarios. The work presented here aims at filling this gap. Using a breast cancer cell proliferation assay (E-Screen), we assessed the joint effects of five mixtures, containing between 3 and 16 estrogenic agents, including compounds as diverse as steroidal hormones (endogenous and synthetic), pesticides, cosmetic additives, and phytoestrogens. CA was employed to predict mixture effects, which were then compared with experimental outcomes. The effects of two of the mixtures tested were additive, being accurately predicted by CA. However, for the three other mixtures, CA slightly overestimated the experimental observations. In view of these results, we hypothesized that the deviations were due to increased metabolism of steroidal estrogens in the mixture setting. We investigated this by testing the impact of two such mixtures on the activation and expression of steroidal estrogen metabolizing enzymes, such as cytochrome P450 (CYP) 1A1, CYP 1B1, and CYP 3A4. Activation of CYP 1B1 and, consequently, a reduction in the levels of steroidal estrogens in the mixture could contribute to the shortfall from the additivity prediction that we observed.

Chemical variations among L-chondrites. IV - Analyses, with petrographic notes, of 13 L-group and 3 LL-group chondrites

NASA Astrophysics Data System (ADS)

Jarosewich, E.; Dodd, R. T.

1985-03-01

Procedures are reviewed for selecting, preparing and analyzing meteorite samples, present new analyses of 16 ordinary chondrites, and discuss variations of Fe, S and Si in the L-group. A tendency for Fe/Mg, S/Mg and Si/Mg to be low in L chondrites of facies d to f testifies that post-metamorphic shock melting played a significant role in the chemical diversification of the L-group. However, these ratios also vary widely and sympathetically in melt-free chondrites, indicating that much of the L-group's chemical variation arose prior to thermal metamorphism and is in that sense primary. If all L chondrites come from one parent body, type-correlated chemical trends suggest: (1) that the body had a tradiational 'onion skin' structure, with metamorphic intensity increasing with depth; and (2) that it formed from material that became more homogeneous, slightly poorer in iron, and significantly richer in sulfur as accretion proceeded.

Chemical Variations Among L-Chondrites--IV. Analyses, with Petrographic Notes, of 13 L-group and 3 LL-group Chondrites

NASA Astrophysics Data System (ADS)

Jarosewich, E.; Dodd, R. T.

1985-03-01

We review our procedures for selecting, preparing and analyzing meteorite samples, present new analyses of 16 ordinary chondrites, and discuss variations of Fe, S and Si in the L-group. A tendency for Fe/Mg, S/Mg and Si/Mg to be low in L chondrites of facies d to f testifies that post-metamorphic shock melting played a significant role in the chemical diversification of the L-group. However, these ratios also vary widely and sympathetically in melt-free chondrites, indicating that much of the L-group's chemical variation arose prior to thermal metamorphism and is in that sense primary. If all L chondrites come from one parent body, type-correlated chemical trends suggest: 1) that the body had a traditional "onion skin" structure, with metamorphic intensity increasing with depth; and 2) that it formed from material that became more homogeneous, slightly poorer in iron, and significantly richer in sulfur as accretion proceeded.

Records of wells, drillers' logs, water-level measurements, and chemical analyses of ground water in Harris and Galveston Counties, Texas, 1984-1989

USGS Publications Warehouse

Coplin, L.S.; Campodonico, Al

1991-01-01

Data for water wells and ground water in Harris and Galveston Counties were collected during 1984-89 by the U.S. Geological Survey. This report presents a compilation of records for 243 wells in Harris and Galveston Counties and drillers' logs for 174 of these wells. Water-level data and chemical-quality data of water for new and previously inventoried wells were also collected. Water levels in 521 wells and chemical analyses of water from 249 wells are presented in this report.

Poisoned Wine: Regulation, Chemical Analyses, and Spanish-French Trade in the 1930s.

PubMed

Suay-Matallana, Ignacio; Guillem-Llobat, Ximo

2018-05-01

This paper describes the resources, scientific spaces, and experts involved in the study of a mass poisoning caused by the drinking of arsenic-contaminated wine exported from Spain to France in 1932. Local and international periodicals record the poisoning of 300 French sailors, and stressed the commercial implications of the case. We discuss the reports prepared by different experts (mainly physicians, agricultural engineers, and customs chemists). Their work was not limited to preparing technical publications or chemical analyses; they also actively defended the quality of their local wine, and played a major role in the discussions regarding the regulation of the international wine market in the 1930s, when new standards regarding the analysis of wine were being considered. Curiously, this well-publicised case of mass poisoning did not have any noticeable consequences in the international regulation of wine. This absence of subsequent regulatory action and the role of experts are central topics of the paper.

Evaluation of food-relevant chemicals in the ToxCast high-throughput screening program

EPA Pesticide Factsheets

Thousands of chemicals are directly added to or come in contact with food, many of which have undergone little to no toxicological evaluation. The landscape of the food-relevant chemical universe was evaluated using cheminformatics, and subsequently the bioactivity of food-relevant chemicals across the publicly available ToxCast highthroughput screening program was assessed. In total, 8659 food-relevant chemicals were compiled including direct food additives, food contact substances, and pesticides. Of these food-relevant chemicals, 4719 had curated structure definition files amenable to defining chemical fingerprints, which were used to cluster chemicals using a selforganizing map approach. Pesticides, and direct food additives clustered apart from one another with food contact substances generally in between, supporting that these categories not only reflect different uses but also distinct chemistries. Subsequently, 1530 food-relevant chemicals were identified in ToxCast comprising 616 direct food additives, 371 food contact substances, and 543 pesticides. Bioactivity across ToxCast was filtered for cytotoxicity to identify selective chemical effects. Initiating analyses from strictly chemical-based methodology or bioactivity/cytotoxicity-driven evaluation presents unbiased approaches for prioritizing chemicals. Although bioactivity in vitro is not necessarily predictive of adverse effects in vivo, these data provide insight into chemical properties and cellu

Nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions.

PubMed

Song, Yong-Hui; Qiu, Guang-Lei; Yuan, Peng; Cui, Xiao-Yu; Peng, Jian-Feng; Zeng, Ping; Duan, Liang; Xiang, Lian-Cheng; Qian, Feng

2011-06-15

Anaerobically digested swine wastewater contains high concentrations of phosphorus (P) and nitrogen (N). A pilot-scale experiment was carried out for nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization. In the pilot plant, a sequencing batch reactor (SBR) and a continuous-flow reactor with struvite accumulation devices were designed and employed. The wastewater pH value was increased by CO(2) stripping, and the struvite crystallization process was performed without alkali and Mg(2+) additions. Results of the long-term operation of the system showed that, both reactors provided up to 85% P removal and recovery over wide ranges of aeration times (1.0-4.0 h), hydraulic retention times (HRT) (6.0-15.0 h) and temperatures (0-29.5°C) for an extended period of 247 d, in which approximate 30% of P was recovered by the struvite accumulation devices. However, 40-90% of NH(4)(+)-N removed was through air stripping instead of being immobilized in the recovered solids. The recovered products were detected and analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and chemical methods, which were proved to be struvite with purity of more than 90%. This work demonstrated the feasibility and effects of nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions. Copyright © 2011 Elsevier B.V. All rights reserved.

[Safety of food additives in Japan].

PubMed

Ito, Sumio

2011-01-01

Recently, many accidents relating to food happened in Japan. The consumer's distrust for food, food companies, and the administration is increasing. The consumer especially has an extreme refusal feeling for chemicals such as food additives and agricultural chemicals, and begins to request agricultural chemical-free vegetables and food additive-free food. Food companies also state no agricultural chemicals and no food additives to correspond with consumers' request and aim at differentiating. The food additive is that the Ministry of Health, Labour and Welfare specifies the one that person's health might not be ruined by providing for Food Sanitation Law Article 10 in our country. The standard for food additives and standard for use of food additives are provided according to regulations of Food Sanitation Law Article 11. Therefore, it is thought that the food additive used is safe now. Then, it reports on the procedure and the safety examination, etc. in our country for designation for food additive this time.

Data Disclosure for Chemical Evaluations

PubMed Central

Barrow, Craig; Borgert, Christopher J.; Conrad, James W.; Edwards, Debra; Felsot, Allan

2012-01-01

Background: Public disclosure of scientific data used by the government to make regulatory decisions for chemicals is a practical step that can enhance public confidence in the scientific basis of such decisions. Objectives: We reviewed the U.S. Environmental Protection Agency’s (EPA) current practices regarding disclosure of data underlying regulatory and policy decisions involving chemicals, including pesticides. We sought to identify additional opportunities for the U.S. EPA to disclose data and, more generally, to promote broad access to data it uses, regardless of origin. Discussion: We recommend that when the U.S. EPA proposes a regulatory determination or other policy decision that relies on scientific research, it should provide sufficient underlying raw data and information about methods to enable reanalysis and attempts to independently reproduce the work, including the sensitivity of results to alternative analyses. This recommendation applies regardless of who conducted the work. If the U.S. EPA is unable to provide such transparency, it should state whether it had full access to all underlying data and methods. A timely version of submitted data cleared of information about confidential business matters and personal privacy should fully meet the standards of transparency described below, including public access sufficient for others to undertake an independent reanalysis. Conclusion: Reliable chemical evaluation is essential for protecting public health and the environment and for ensuring availability of useful chemicals under appropriate conditions. Permitting qualified researchers to endeavor to independently reproduce the analyses used in regulatory determinations of pesticides and other chemicals would increase confidence in the scientific basis of such determinations. PMID:23228957

Data disclosure for chemical evaluations.

PubMed

Lutter, Randall; Barrow, Craig; Borgert, Christopher J; Conrad, James W; Edwards, Debra; Felsot, Allan

2013-02-01

Public disclosure of scientific data used by the government to make regulatory decisions for chemicals is a practical step that can enhance public confidence in the scientific basis of such decisions. We reviewed the U.S. Environmental Protection Agency's (EPA) current practices regarding disclosure of data underlying regulatory and policy decisions involving chemicals, including pesticides. We sought to identify additional opportunities for the U.S. EPA to disclose data and, more generally, to promote broad access to data it uses, regardless of origin. We recommend that when the U.S. EPA proposes a regulatory determination or other policy decision that relies on scientific research, it should provide sufficient underlying raw data and information about methods to enable reanalysis and attempts to independently reproduce the work, including the sensitivity of results to alternative analyses. This recommendation applies regardless of who conducted the work. If the U.S. EPA is unable to provide such transparency, it should state whether it had full access to all underlying data and methods. A timely version of submitted data cleared of information about confidential business matters and personal privacy should fully meet the standards of transparency described below, including public access sufficient for others to undertake an independent reanalysis. Reliable chemical evaluation is essential for protecting public health and the environment and for ensuring availability of useful chemicals under appropriate conditions. Permitting qualified researchers to endeavor to independently reproduce the analyses used in regulatory determinations of pesticides and other chemicals would increase confidence in the scientific basis of such determinations.

Proteomic analyses of the environmental toxicity of carcinogenic chemicals

EPA Science Inventory

Protein expression and posttranslational modifications consistently change in response to the exposure to environmental chemicals. Recent technological advances in proteomics provide new tools for more efficient characterization of protein expression and posttranslational modific...

Tying Biological Activity to Changes in Sea Spray Aerosol Chemical Composition via Single Particle Analyses

NASA Astrophysics Data System (ADS)

Sultana, C. M.; Lee, C.; Collins, D. B.; Axson, J. L.; Laskina, O.; Grandquist, J. R.; Grassian, V. H.; Prather, K. A.

2014-12-01

In remote marine environments, sea spray aerosols (SSA) often represent the greatest aerosol burden, thus having significant impacts on direct radiative interactions and cloud processes. Previous studies have shown that SSA is a complex mixture of inorganic salts and an array of dissolved and particulate organic components. Enrichment of SSA organic content is often correlated to seawater chlorophyll concentrations, a measure of oceanic biological activity. As the physical and chemical properties of aerosols control their radiative effects, recent studies conducted by the Center for Aerosol Impacts on Climate and the Environment have endeavored to further elucidate the ties between marine biological activity and primary SSA chemical composition using highly time resolved single particle analyses. A series of experiments performed in the recently developed Marine Aerosol Reference Tank evaluated the effect of changing marine microbial populations on SSA chemical composition, which was monitored via an aerosol time-of-flight mass spectrometer and a variety of offline spectroscopic and microscopic techniques. Each experiment was initiated using unfiltered and untreated seawater, thus maintaining a high level of biogeochemical complexity. This study is the first of its kind to capture daily changes in the primary SSA mixing state over the growth and death of a natural phytoplankton bloom. Increases in organic aerosol types (0.4-3 μm), internally and externally mixed with sea salt, could not be correlated to chlorophyll concentrations. Maximum production of these populations occurred two to four days after the in vivo chlorophyll fluorescence peaked in intensity. This work is in contrast to the current paradigm of correlating SSA organic content to seawater chlorophyll concentration.

The Chemical Basis of Thiol Addition to Nitro-conjugated Linoleic Acid, a Protective Cell-signaling Lipid*♦

PubMed Central

Turell, Lucía; Vitturi, Darío A.; Coitiño, E. Laura; Lebrato, Lourdes; Möller, Matías N.; Sagasti, Camila; Salvatore, Sonia R.; Woodcock, Steven R.; Alvarez, Beatriz; Schopfer, Francisco J.

2017-01-01

Nitroalkene fatty acids are formed in vivo and exert protective and anti-inflammatory effects via reversible Michael addition to thiol-containing proteins in key signaling pathways. Nitro-conjugated linoleic acid (NO2-CLA) is preferentially formed, constitutes the most abundant nitrated fatty acid in humans, and contains two carbons that could potentially react with thiols, modulating signaling actions and levels. In this work, we examined the reactions of NO2-CLA with low molecular weight thiols (glutathione, cysteine, homocysteine, cysteinylglycine, and β-mercaptoethanol) and human serum albumin. Reactions followed reversible biphasic kinetics, consistent with the presence of two electrophilic centers in NO2-CLA located on the β- and δ-carbons with respect to the nitro group. The differential reactivity was confirmed by computational modeling of the electronic structure. The rates (kon and koff) and equilibrium constants for both reactions were determined for different thiols. LC-UV-Visible and LC-MS analyses showed that the fast reaction corresponds to β-adduct formation (the kinetic product), while the slow reaction corresponds to the formation of the δ-adduct (the thermodynamic product). The pH dependence of the rate constants, the correlation between intrinsic reactivity and thiol pKa, and the absence of deuterium solvent kinetic isotope effects suggested stepwise mechanisms with thiolate attack on NO2-CLA as rate-controlling step. Computational modeling supported the mechanism and revealed additional features of the transition states, anionic intermediates, and final neutral products. Importantly, the detection of cysteine-δ-adducts in human urine provided evidence for the biological relevance of this reaction. Finally, human serum albumin was found to bind NO2-CLA both non-covalently and to form covalent adducts at Cys-34, suggesting potential modes for systemic distribution. These results provide new insights into the chemical basis of NO2-CLA

Evaluation of food-relevant chemicals in the ToxCast high-throughput screening program.

PubMed

Karmaus, Agnes L; Filer, Dayne L; Martin, Matthew T; Houck, Keith A

2016-06-01

Thousands of chemicals are directly added to or come in contact with food, many of which have undergone little to no toxicological evaluation. The landscape of the food-relevant chemical universe was evaluated using cheminformatics, and subsequently the bioactivity of food-relevant chemicals across the publicly available ToxCast highthroughput screening program was assessed. In total, 8659 food-relevant chemicals were compiled including direct food additives, food contact substances, and pesticides. Of these food-relevant chemicals, 4719 had curated structure definition files amenable to defining chemical fingerprints, which were used to cluster chemicals using a selforganizing map approach. Pesticides, and direct food additives clustered apart from one another with food contact substances generally in between, supporting that these categories not only reflect different uses but also distinct chemistries. Subsequently, 1530 food-relevant chemicals were identified in ToxCast comprising 616 direct food additives, 371 food contact substances, and 543 pesticides. Bioactivity across ToxCast was filtered for cytotoxicity to identify selective chemical effects. Initiating analyses from strictly chemical-based methodology or bioactivity/cytotoxicity-driven evaluation presents unbiased approaches for prioritizing chemicals. Although bioactivity in vitro is not necessarily predictive of adverse effects in vivo, these data provide insight into chemical properties and cellular targets through which foodrelevant chemicals elicit bioactivity. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

The effect of benzalkonium chloride additions to AH Plus sealer. Antimicrobial, physical and chemical properties.

PubMed

Arias-Moliz, M T; Ruiz-Linares, M; Cassar, G; Ferrer-Luque, C M; Baca, P; Ordinola-Zapata, R; Camilleri, J

2015-07-01

The aim of this study was to determine the antimicrobial and antibiofilm activities and physicochemical properties of AH Plus sealer mixed with different concentrations of benzalkonium chloride (BC). AH Plus was tested alone and mixed with 1%, 2% and 3% of BC. The antimicrobial and antibiofilm activities of the sealers against Enterococcus faecalis were evaluated by the direct contact test (DCT) and by confocal laser scanning microscopy, respectively. Setting time, flow and solubility were assessed according to ANSI/ADA specifications. Microhardness and contact angle tests were also performed. The chemical changes of the sealers were evaluated by X-ray diffraction analysis, and both Fourier transform infrared spectroscopy (FT-IR) and attenuated total reflectance Fourier transform infrared (ATR FT-IR). AH Plus+3% BC was the only sealer to promote total elimination of E. faecalis and the biovolume in this group was significantly lower than in the rest of the sealers (p>0.05). The physical properties of the sealers were according to the ANSI/ADA specifications. The microhardness decreased significantly when BC was added and a significant reduction in contact angle was obtained when incorporating 2% and 3% BC (p<0.05). No phase changes were observed with the modified sealers. The addition of 2% or higher concentrations BC to AH Plus showed antimicrobial and antibiofilm activities without affecting the properties specified in ANSI/ADA standards. However, additives to the root canal sealer altered other physical and chemical properties that are not commonly found in the literature to evaluate filling materials. The present study highlights that the antimicrobial properties of AH Plus can be significantly improved with the addition of BC. Testing beyond what is specified in standards may be indicated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Towards interoperable and reproducible QSAR analyses: Exchange of datasets.

PubMed

Spjuth, Ola; Willighagen, Egon L; Guha, Rajarshi; Eklund, Martin; Wikberg, Jarl Es

2010-06-30

QSAR is a widely used method to relate chemical structures to responses or properties based on experimental observations. Much effort has been made to evaluate and validate the statistical modeling in QSAR, but these analyses treat the dataset as fixed. An overlooked but highly important issue is the validation of the setup of the dataset, which comprises addition of chemical structures as well as selection of descriptors and software implementations prior to calculations. This process is hampered by the lack of standards and exchange formats in the field, making it virtually impossible to reproduce and validate analyses and drastically constrain collaborations and re-use of data. We present a step towards standardizing QSAR analyses by defining interoperable and reproducible QSAR datasets, consisting of an open XML format (QSAR-ML) which builds on an open and extensible descriptor ontology. The ontology provides an extensible way of uniquely defining descriptors for use in QSAR experiments, and the exchange format supports multiple versioned implementations of these descriptors. Hence, a dataset described by QSAR-ML makes its setup completely reproducible. We also provide a reference implementation as a set of plugins for Bioclipse which simplifies setup of QSAR datasets, and allows for exporting in QSAR-ML as well as old-fashioned CSV formats. The implementation facilitates addition of new descriptor implementations from locally installed software and remote Web services; the latter is demonstrated with REST and XMPP Web services. Standardized QSAR datasets open up new ways to store, query, and exchange data for subsequent analyses. QSAR-ML supports completely reproducible creation of datasets, solving the problems of defining which software components were used and their versions, and the descriptor ontology eliminates confusions regarding descriptors by defining them crisply. This makes is easy to join, extend, combine datasets and hence work collectively, but

Towards interoperable and reproducible QSAR analyses: Exchange of datasets

PubMed Central

2010-01-01

Background QSAR is a widely used method to relate chemical structures to responses or properties based on experimental observations. Much effort has been made to evaluate and validate the statistical modeling in QSAR, but these analyses treat the dataset as fixed. An overlooked but highly important issue is the validation of the setup of the dataset, which comprises addition of chemical structures as well as selection of descriptors and software implementations prior to calculations. This process is hampered by the lack of standards and exchange formats in the field, making it virtually impossible to reproduce and validate analyses and drastically constrain collaborations and re-use of data. Results We present a step towards standardizing QSAR analyses by defining interoperable and reproducible QSAR datasets, consisting of an open XML format (QSAR-ML) which builds on an open and extensible descriptor ontology. The ontology provides an extensible way of uniquely defining descriptors for use in QSAR experiments, and the exchange format supports multiple versioned implementations of these descriptors. Hence, a dataset described by QSAR-ML makes its setup completely reproducible. We also provide a reference implementation as a set of plugins for Bioclipse which simplifies setup of QSAR datasets, and allows for exporting in QSAR-ML as well as old-fashioned CSV formats. The implementation facilitates addition of new descriptor implementations from locally installed software and remote Web services; the latter is demonstrated with REST and XMPP Web services. Conclusions Standardized QSAR datasets open up new ways to store, query, and exchange data for subsequent analyses. QSAR-ML supports completely reproducible creation of datasets, solving the problems of defining which software components were used and their versions, and the descriptor ontology eliminates confusions regarding descriptors by defining them crisply. This makes is easy to join, extend, combine datasets

Assessment of chemical analyses by means of portable XRF in the Roman mortars of Complutum archaeological site (Spain)

NASA Astrophysics Data System (ADS)

Ergenç, Duygu; Freire, David; Fort, Rafael

2016-04-01

The chemical characterization of lime mortars used in Roman period has a great significance and plays a key role in the acquisition of knowledge with respect to construction technology, raw materials and, accordingly, in its conservation works. When it comes to cultural heritage studies, sampling is always complicated since the minimum damage is the primary concern. The use of non-destructive techniques and direct measurements with portable devices reduce the amount of samples and time consumed in analyses, consequently it could be stated that such techniques are extremely useful in conservation and restoration works. In this study, the portable XRF device was used to determine the composition of chemical elements which compose the Roman lime mortars in the archaeological site of Complutum, Alcalá de Henares (Madrid, Spain) which is listed as a World Heritage Site by UNESCO since 1998. Portable XRF devices have some detection limits below the ones of the laboratory equipment that are immovable and require sampling. In order to correlate the results, sampling and grinding were initially done to prepare the powders for the laboratory XRF analysis with the following elements: Si, Al, Fe, Ca, Mg, K, Ti, Nb, Zr, Sr, Rb, Pb, Zn and Cr. The analyses of the powdered samples were conducted with the laboratory equipment PHILIPS Magix Pro (PW-2440) from the Centre of Scientific Instrumentation CIC in the University of Granada, and the results were compared to the results gathered with X Ray Florescence (EDTRX) THERMO NITON model XL3T from the Petrophysics Laboratory Geosciences Institute IGEO (CSIC-UCM). Analyses were performed on the surfaces of the samples -without any previous preparation-, and on the powdered samples to compare the variations between both traditional XRF analyses and the portable XRF. A good correlation was found among the results obtained by the laboratory equipment, the portable device as well as the surface measurements. The results of this study

Chemical and sensory characteristics of frozen wheygurt with the addition of taro and lesser yam flours as thickening agent

NASA Astrophysics Data System (ADS)

Nurhartadi, E.; Utami, R.; Widowati, E.; Karunawati, B. M.

2018-01-01

Cheese whey is a waste product from cheese processing. It has low solid contents thus required the addition of a thickening agent. Lactic acid bacteria could utilize it in the fermented drink. This research aims to study the effect of taro and lesser yam flour addition as a thickening agent on chemical and sensory characteristics of frozen wheygurt. This research used Complete Randomized Design (CRD) with one factor that is variation ratio of taro and lesser yam flour F1 (4: 0), F2 (3: 1), F3 (2: 2), F4 (1: 3), F5 (0: 4). The number of lactic acid bacteria cell determined by using hemocytometer. The lactic acid content determined by the titrimetric method by using 0.1 N NaOH and phenolphthalein as indicator. pH value measured with pH meter. Sensory characteristics evaluated using hedonic test. The result showed that the addition of taro and lesser yam flour have a significant effect on the number of lactic acid bacteria in frozen wheygurt. The higher lesser yam flour addition, the higher lactic acid bacteria count on frozen wheygurt, due to lesser yam higher glucose and fructo-oligosaccharide content than taro. The higher lesser yam addition, the higher the lactic acid produced. The higher the total bacteria and higher levels of lactic acid, the lower the pH obtained. The conclusion of this study is addition ratio of taro and lesser yam flour effect on the chemical characteristics of frozen wheygurt. There is no difference in the level of acceptance of the panelists in sensory evaluation.

Food additives

PubMed Central

Spencer, Michael

1974-01-01

Food additives are discussed from the food technology point of view. The reasons for their use are summarized: (1) to protect food from chemical and microbiological attack; (2) to even out seasonal supplies; (3) to improve their eating quality; (4) to improve their nutritional value. The various types of food additives are considered, e.g. colours, flavours, emulsifiers, bread and flour additives, preservatives, and nutritional additives. The paper concludes with consideration of those circumstances in which the use of additives is (a) justified and (b) unjustified. PMID:4467857

Synergistic influence of Al, Ni, Bi and Sn addition to a zinc bath upon growth kinetics and the structure of coatings

NASA Astrophysics Data System (ADS)

Kania, H.; Liberski, P.

2012-05-01

In this article the authors have analysed the current knowledge about the influence of alloy additions used in galvanizing baths. The optimum concentration of Al, Ni, Bi and Sn addition has been established. Some tests have been conducted to determine the synergistic effect of the addition of AlNiBiSn to a zinc bath upon the structure and growth kinetics of coatings. The structure of the coatings obtained on steel with low silicon contents and on Sandelin steel as well as their chemical composition have been revealed. It has been established that the addition of AlNiBiSn helps to reduce excessive growth of coating on Sandelin steel. The chemical composition and the structure of the coating on Sandelin steel are similar to the chemical composition and structure obtained on steel with regular silicon contents.

Effect of water treatment additives on lime softening residual trace chemical composition--implications for disposal and reuse.

PubMed

Cheng, Weizhi; Roessler, Justin; Blaisi, Nawaf I; Townsend, Timothy G

2014-12-01

Drinking water treatment residues (WTR) offer potential benefits when recycled through land application. The current guidance in Florida, US allows for unrestricted land application of lime softening WTR; alum and ferric WTR require additional evaluation of total and leachable concentrations of select trace metals prior to land application. In some cases a mixed WTR is produced when lime softening is accompanied by the addition of a coagulant or other treatment chemical; applicability of the current guidance is unclear. The objective of this research was to characterize the total and leachable chemical content of WTR from Florida facilities that utilize multiple treatment chemicals. Lime and mixed lime WTR samples were collected from 18 water treatment facilities in Florida. Total and leachable concentrations of the WTR were measured. To assess the potential for disposal of mixed WTR as clean fill below the water table, leaching tests were conducted at multiple liquid to solid ratios and under reducing conditions. The results were compared to risk-based soil and groundwater contamination thresholds. Total metal concentrations of WTR were found to be below Florida soil contaminant thresholds with Fe found in the highest abundance at a concentration of 3600 mg/kg-dry. Aluminum was the only element that exceeded the Florida groundwater contaminant thresholds using SPLP (95% UCL = 0.23 mg/L; risk threshold = 0.2 mg/L). Tests under reducing conditions showed elevated concentrations of Fe and Mn, ranging from 1 to 3 orders of magnitude higher than SPLP leachates. Mixed lime WTR concentrations (total and leachable) were lower than the ferric and alum WTR concentrations, supporting that mixed WTR are appropriately represented as lime WTR. Testing of WTR under reducing conditions demonstrated the potential for release of certain trace metals (Fe, Al, Mn) above applicable regulatory thresholds; additional evaluation is needed to assess management options where

Physico-chemical protection, rather than biochemical composition, governs the responses of soil organic carbon decomposition to nitrogen addition in a temperate agroecosystem.

PubMed

Tan, Wenbing; Wang, Guoan; Huang, Caihong; Gao, Rutai; Xi, Beidou; Zhu, Biao

2017-11-15

The heterogeneous responses of soil organic carbon (SOC) decomposition in different soil fractions to nitrogen (N) addition remain elusive. In this study, turnover rates of SOC in different aggregate fractions were quantified based on changes in δ 13 C following the conversion of C 3 to C 4 vegetation in a temperate agroecosystem. The turnover of both total organic matter and specific organic compound classes within each aggregate fraction was inhibited by N addition. Moreover, the intensity of inhibition increases with decreasing aggregate size and increasing N addition level, but does not vary among chemical compound classes within each aggregate fraction. Overall, the response of SOC decomposition to N addition is dependent on the physico-chemical protection of SOC by aggregates and minerals, rather than the biochemical composition of organic substrates. The results of this study could help to understand the fate of SOC in the context of increasing N deposition. Copyright © 2017 Elsevier B.V. All rights reserved.

The enhanced stability and biodegradation of dispersed crude oil droplets by Xanthan Gum as an additive of chemical dispersant.

PubMed

Wang, Aiqin; Li, Yiming; Yang, Xiaolong; Bao, Mutai; Cheng, Hua

2017-05-15

It is necessary for chemical dispersant to disperse oil effectively and maintain the stability of oil droplets. In this work, Xanthan Gum (XG) was used as an environmentally friendly additive in oil dispersant formulation to enhance the stability and biodegradation of dispersed crude oil droplets. When XG was used together with chemical dispersant 9500A, the dispersion effectiveness of crude oil in artificial sea water (ASW) and the oil droplet stability were both greatly enhanced. In the presence of XG, lower concentration of 9500A was needed to achieve the effective dispersion and stabilization. In addition to the enhancement of dispersion and stabilization, it was found that the biodegradation rate of crude oil by bacteria was dramatically enhanced when a mixture of 9500A and XG was used as a dispersant. Because of the low environmental impact of XG, this would be a potential way to formulate the dispersant with lower toxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Microbial and Chemical Combo Additives on Nutritive Value and Fermentation Characteristic of Whole Crop Barley Silage

PubMed Central

Kim, Dong Hyeon; Amanullah, Sardar M.; Lee, Hyuk Jun; Joo, Young Ho; Kim, Sam Churl

2015-01-01

This study was conducted to assess the effects of microbial and chemical combo additives on nutritive values, fermentation indices and aerobic stability of whole crop barley silage. Barley forage (Youngyang) was harvested at about 30% dry matter (DM) by treatments, chopped to 5 cm length and treated with distilled water only (CON), Lactobacillus plantarum (INO), propionic acid (PRO) or an equal mixture of INO and PRO (MIX). Barley forages were ensiled in 4 replications for 0, 2, 7, and 100 days. On 100 days of ensiling, MIX silage had higher (p<0.05) in vitro DM digestibility than CON silage, but lower (p<0.05) acid detergent fiber concentration. The pH in all treated silages was lower (p<0.05) than CON silage. The MIX silage had higher (p<0.05) lactate concentration and lactate to acetate ratio than in CON, but lower (p<0.05) yeast count. Aerobic stability in CON, PRO, and MIX silages were higher (p<0.05) than in INO silage. It is concluded that microbial and chemical combo additives using L. plantarum and propionic acid could efficiently improve nutritive values of barley silage in terms of increased in vitro DM digestibility compared to other treatments. In addition, all treatments except CON reduced yeast count which is the initiate microorganism of aerobic spoilage. PMID:26323517

Burst and Principal Components Analyses of MEA Data Separates Chemicals by Class

EPA Science Inventory

Microelectrode arrays (MEAs) detect drug and chemical induced changes in action potential "spikes" in neuronal networks and can be used to screen chemicals for neurotoxicity. Analytical "fingerprinting," using Principal Components Analysis (PCA) on spike trains recorded from prim...

The effect of hyaluronic acid addition on the properties of smoked homogenised sausages.

PubMed

Zając, Marzena; Kulawik, Piotr; Tkaczewska, Joanna; Migdał, Władysław; Filipczak-Fiutak, Magda; Fiutak, Grzegorz

2017-06-01

This research studied the possibility of using hyaluronic acid (HA) as a food additive for meat emulsions to create a novel functional food with improved rheological and water binding properties. Sausages with 200 and 500 g kg -1 water addition were supplemented with 0, 0.01, 0.05 and 0.1 g kg -1 of HA and stored for 14 days in vacuum. Rheology, texture, weight losses, proximate composition and microbiological analyses were performed together with the sensory evaluation of produced sausages. Surprisingly, the results show that the addition of 0.05 and 0.1 g kg -1 HA reduced yield and the stability of meat emulsion by causing water outflow from the product and decreased the sensory scores of the produced sausages. The sausage with 500 g kg -1 water and 0.01 g kg -1 HA addition was the only economically viable option for introducing the product on the market. HA has a potential of being a perfect functional food additive for meat industry, although further research regarding processing conditions should be performed. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Physical Characteristics, Chemical Composition, Organoleptic Test And The Number Of Microbes In The Biscuits With Addition Of Flour Banana Peels

NASA Astrophysics Data System (ADS)

Hernawati; Aryani, A.; Shintawati, R.

2017-02-01

The purpose of this study to analyze the physical characteristics, chemical composition and organoleptic test of biscuit flour with the addition of flour banana peel. Materials used are banana peels Kepok. Kepok banana peel has been found to contain high fiber food. Biscuit-making stage includes the formation of cream, adding flour and wheat flour dietary fiber from banana peels to concentrations of 0% as control, 25%, 50% and 75% of 100 grams of wheat flour; mixing; molding; baking in the oven for 20-25 minutes with a temperature of 180°C. Parameters to be measured, namely the physical characteristics include: hardness, softness, consistency, crispness. Furthermore, the biscuits were tested by chemical analysis (proximate). Organoleptic test include: aroma, taste, mouthfeel, aftertaste. Data were analyzed statistically using SAS computing programs. Physical and organoleptic test results biscuits with the addition of flour banana peels has sufficient level of preference between like-liked. Based on the results of the proximate analysis of biscuits with the addition of flour banana peels has generally been in accordance with the National Standards of Indonesia (SNI). Conclusion of the study that the addition of flour banana peels in biscuits has the potential to become functional foods that contain high fiber.

Chemical analyses of surface waters in Oklahoma, September - December, 1944

USGS Publications Warehouse

,

1945-01-01

Red River at Denison Dam, Texas Sport samples were collected at the remainder of the stations. The analyses of the spot samples were made largely in a laboratory provided by the Oklahoma A. & M. College, under the supervision of Dr. O.M. Smith, Head, Department of Chemistry; Dr. S.R. Wood, Associate Professor of Chemistry; and W.W. Hastings, U.S. Geological Survey. The daily samples were analyzed in the water resources laboratory of the Geological Survey at Austin, Texas. These data have been summarized in a report to the Oklahoma Planning and Resources Board prepared by the U.S. Geological Survey, March 1, 1945. The streams of Oklahoma are classified into two major drainage basins: the Arkansas River and the Red River and their tributaries. The attached analyses are arranged in geographical order for their respective drainage basins, with records listed in downstream order for stations on the main stem first, followed by the analyses for the tributaries. When available, the mean daily discharge is given for the analyses.

Toxicogenomics concepts and applications to study hepatic effects of food additives and chemicals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stierum, Rob; Heijne, Wilbert; Kienhuis, Anne

2005-09-01

Transcriptomics, proteomics and metabolomics are genomics technologies with great potential in toxicological sciences. Toxicogenomics involves the integration of conventional toxicological examinations with gene, protein or metabolite expression profiles. An overview together with selected examples of the possibilities of genomics in toxicology is given. The expectations raised by toxicogenomics are earlier and more sensitive detection of toxicity. Furthermore, toxicogenomics will provide a better understanding of the mechanism of toxicity and may facilitate the prediction of toxicity of unknown compounds. Mechanism-based markers of toxicity can be discovered and improved interspecies and in vitro-in vivo extrapolations will drive model developments in toxicology. Toxicologicalmore » assessment of chemical mixtures will benefit from the new molecular biological tools. In our laboratory, toxicogenomics is predominantly applied for elucidation of mechanisms of action and discovery of novel pathway-supported mechanism-based markers of liver toxicity. In addition, we aim to integrate transcriptome, proteome and metabolome data, supported by bioinformatics to develop a systems biology approach for toxicology. Transcriptomics and proteomics studies on bromobenzene-mediated hepatotoxicity in the rat are discussed. Finally, an example is shown in which gene expression profiling together with conventional biochemistry led to the discovery of novel markers for the hepatic effects of the food additives butylated hydroxytoluene, curcumin, propyl gallate and thiabendazole.« less

Chemical analyses of stream sediment in the Tar Creek basin of the Picher mining area, northeast Oklahoma

USGS Publications Warehouse

Parkhurst, David L.; Doughten, Michael; Hearn,, Paul P.

1988-01-01

Chemical analyses are presented for 47 sediment samples from the Tar Creek drainage in the Picher mining area of northeast Oklahoma. The samples were taken in December 1983, June 1984, and June 1985. All of the samples were taken downstream from mine-water discharge points of abandoned lead and zinc mines. The 34 samples taken in December 1983 and June 1984 were analyzed semiquantitatively by emission spectrography for 64 elements and quantitatively for cadmium, copper, iron, manganese, nickel, lead, sulfur, zinc, and organic carbon. The 13 samples taken in June 1985 were analyzed quantitatively for aluminum, cadmium, cobalt, chromium, copper, iron, manganese, molybdenum, nickel, phosphorus, lead, sulfur, silicon, titanium, vanadium, zinc, and organic carbon.

Chemical and biomolecular analyses to discriminate three taxa of Pistacia genus from Sardinia Island (Italy) and their antifungal activity.

PubMed

Marengo, Arianna; Piras, Alessandra; Falconieri, Danilo; Porcedda, Silvia; Caboni, Pierluigi; Cortis, Pierluigi; Foddis, Caterina; Loi, Claudia; Gonçalves, Maria José; Salgueiro, Lígia; Maxia, Andrea

2017-09-20

This work reports the results and the comparison concerning the chemical and biomolecular analyses and the antifungal activity of three wild Pistacia species (Anacardiaceae) from Sardinia. Volatile oils from leaves and twigs of Pistacia x saportae, Pistacia lentiscus and Pistacia terebinthus were characterised using GC-FID and GC-MS techniques and tested against some fungal strains. Two DNA nuclear regions (ITS and 5S-rRNA-NTS) were amplified through PCR technique and sequenced. The three **Pistacia have similar chemical profile, although there are some important quantitative differences. The analysis of ITS and 5S-rRNA-NTS regions, reveals a species-specific nucleotide variation among the three **taxa. This method could emerge as a powerful tool for the species identification, especially because the discrimination of these three **taxa appears difficult for non-expert botanists. Concerning the antifungal activity, P. lentiscus and P. x saportae show the highest activity against Cryptococcus neoformans, with a MIC value of 0.32 μL/mL.

Mineralogical and Chemical Characterization of Lunar Highland Regolith: Lessons Learned from Mare Soils

NASA Technical Reports Server (NTRS)

Taylor, L. A.; Cahill, J. T.; Patchen, A.; Pieters, C.; Morris, R.; Keller, L. P.; McKay, D. S.

2001-01-01

The Lunar Soil Characterization Consortium has begun study of the <45 m fractions of ten representative highland soils, chosen for their contrasting maturities. Difficulties are addressed in the modal and chemical analyses of these highland soils. Additional information is contained in the original extended abstract.

Chemical analyses of geothermal waters from a South Louisiana well

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hankins, B.E.; Chavanne, R.E.; Ham, R.A.

1977-11-16

The abandoned Edna Delcambre No. 1 gas well, about 8 miles south of Delcambre, Louisiana was reopened and bottom-hole and flowing samples were collected. McNeese State University was responsible for the analyses of the products of the well. Typical values from the analyses are shown for such quantities as: pH, turbidity, conductance, density, total dissolved solids, hardness, viscosity, dissolved silicates, chlorides, bicarbonates, etc. Some observations on these values are made. (MHR)

Accelerated Stability Studies on Dried Extracts of Centella asiatica Through Chemical, HPLC, HPTLC, and Biological Activity Analyses.

PubMed

Kaur, Ishtdeep; Suthar, Nancy; Kaur, Jasmeen; Bansal, Yogita; Bansal, Gulshan

2016-10-01

Regulatory guidelines recommend systematic stability studies on a herbal product to establish its shelf life. In the present study, commercial extracts (Types I and II) and freshly prepared extract (Type III) of Centella asiatica were subjected to accelerated stability testing for 6 months. Control and stability samples were evaluated for organoleptics, pH, moisture, total phenolic content (TPC), asiatic acid, kaempherol, and high-performance thin layer chromatography fingerprints, and for antioxidant and acetylcholinesterase inhibitory activities. Markers and TPC and both the activities of each extract decreased in stability samples with respect to control. These losses were maximum in Type I extract and minimum in Type III extract. Higher stability of Type III extract than others might be attributed to the additional phytoconstituents and/or preservatives in it. Pearson correlation analysis of the results suggested that TPC, asiatic acid, and kaempferol can be taken as chemical markers to assess chemical and therapeutic shelf lives of herbal products containing Centella asiatica. © The Author(s) 2016.

Nanofibrillated cellulose as an additive in papermaking process: A review.

PubMed

Boufi, Sami; González, Israel; Delgado-Aguilar, Marc; Tarrès, Quim; Pèlach, M Àngels; Mutjé, Pere

2016-12-10

During the last two decades, cellulose nanofibres (CNF) have emerged as a promising, sustainable reinforcement with outstanding potential in material sciences. Though application of CNF in papermaking is recent, it is expected to find implementation in the near future to give a broader commercial market to this type of cellulose. The present review highlights recent progress in the field of the application of cellulose nanofibres as additives in papermaking. The effect of CNF addition on the wet end process is analysed according to the type of pulp used for papermaking. According to the literature consulted, improvement in paper's overall properties after CNF addition depended not only on the type and amount of CNF applied, but also in the pulp's origin and treatment. Bulk and surface application of CNF also presented significant differences regarding paper's final properties. This review also revises the mechanisms behind CNF reinforcing effect on paper and the effect of chemically modified CNF as additives. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of casein and inulin addition on physico-chemical characteristics of low fat camel dairy cream.

PubMed

Ziaeifar, Leila; Labbafi Mazrae Shahi, Mohsen; Salami, Maryam; Askari, Gholam R

2018-05-21

The effect of the addition of the camel casein fraction on some physico-chemical properties of low fat camel milk cream was studied. Oil-in-water emulsions, 25, 30, and 35 (w/w) fat, were prepared using inulin, camel skim milk, milk fat and variable percentages of casein (1, 2, and 3% w/w). The droplet size, ζ-potential, surface protein concentration, viscosity and surface tension of low fat dairy creams was measured. Cream containing 2% (w/w) casein had better stability. The modifications in physico-chemical properties appeared to be driven by changes in particle size distribution caused by droplet aggregation. The cream containing 2% casein leads to a gradual decrease in droplet size, as the particle size decreased, apparent viscosity increased. When casein concentration increased, ζ-potential decreased due to combination of c terminal (negative charge) with the surface of fat particles but steric repulsion improved textural properties. Cream with 30% fat and 2% casein had the best result. Copyright © 2018 Elsevier B.V. All rights reserved.

GRANNY, a data bank of chemical analyses of Laramide and younger high-silica rhyolites and granites from Colorado and north-central New Mexico

USGS Publications Warehouse

Steigerwald, Celia H.; Mutschler, Felix E.; Ludington, Steve

1983-01-01

GRANNY is a data bank containing information on 507 chemically analyzed Laramide or younger high-silica rhyolites and granites from Colorado and north-central New Mexico. The data were compiled from both published and unpublished sources. The data bank is designed to aid in the recognition of igneous rocks with a high exploration potential for the discovery of molybdenum (and other lithophile element) deposits. Information on source reference, geographic location, age, mineralogic and petrologic characteristics, major constituent analyses, and trace element analyses for each sample are given. The data bank is available in two formats: 1) paper- or microfiche-hardcopy, and 2) fixed format computer readable magnetic tape.

A computational method for the identification of new candidate carcinogenic and non-carcinogenic chemicals.

PubMed

Chen, Lei; Chu, Chen; Lu, Jing; Kong, Xiangyin; Huang, Tao; Cai, Yu-Dong

2015-09-01

Cancer is one of the leading causes of human death. Based on current knowledge, one of the causes of cancer is exposure to toxic chemical compounds, including radioactive compounds, dioxin, and arsenic. The identification of new carcinogenic chemicals may warn us of potential danger and help to identify new ways to prevent cancer. In this study, a computational method was proposed to identify potential carcinogenic chemicals, as well as non-carcinogenic chemicals. According to the current validated carcinogenic and non-carcinogenic chemicals from the CPDB (Carcinogenic Potency Database), the candidate chemicals were searched in a weighted chemical network constructed according to chemical-chemical interactions. Then, the obtained candidate chemicals were further selected by a randomization test and information on chemical interactions and structures. The analyses identified several candidate carcinogenic chemicals, while those candidates identified as non-carcinogenic were supported by a literature search. In addition, several candidate carcinogenic/non-carcinogenic chemicals exhibit structural dissimilarity with validated carcinogenic/non-carcinogenic chemicals.

Enhanced anti-counterfeiting measures for additive manufacturing: coupling lanthanide nanomaterial chemical signatures with blockchain technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kennedy, Zachary C.; Stephenson, David E.; Christ, Josef F.

The significant rise of additive manufacturing (AM) in recent years is in part due to the open sourced nature of the printing processes and reduced cost and capital barriers relative to traditional manufacturing. However, this democratization of manufacturing spurs an increased demand for producers and end-users to verify the authenticity and quality of individual parts. To this end, we introduce an anti-counterfeiting method composed of first embedding engineered nanomaterials into features of a 3D-printed part followed by non-destructive interrogation of these features to quantify a chemical signature profile. The part specific chemical signature data is then linked to a securitized,more » distributed, and time-stamped blockchain ledger entry. To demonstrate the utility of this approach, lanthanide-aspartic acid nanoscale coordination polymers (Ln3+- Asp NCs) / poly(lactic) acid (PLA) composites were formulated and transformed into a filament feedstock for fused deposition modeling (FDM) 3D printing. In the present case, a quick-response (QR) code containing the doped Ln3+-Asp NCs was printed using a dual-extruder FDM printer into pure PLA parts. The QR code provides a searchable reference to an Ethereum-based blockchain entry. The QR code physical features also serve as defined areas to probe the signatures arising from the embedded Ln3+-Asp NCs. Visible fluorescence emission with UV-excitation was quantified in terms of color using a smartphone camera and incorporated into blockchain entries. Ultimately, linking unique chemical signature data to blockchain databases is anticipated to make the costs of counterfeiting AM materials significantly more prohibitive and transactions between those in the supply chain more trustworthy.« less

Theoretical and practical aspects of improving the durability of steel reinforcement in transport designs, using passivation and plasticizing chemical additives

NASA Astrophysics Data System (ADS)

Velichko, Evgenij; Talipov, Linar

2017-10-01

The article deals with the problem of steel reinforcement corrosion in reinforced concrete structures exposed to aggressive media, in particular in reinforced concrete construction of transport infrastructure, in snowy areas, and subject to the influence of chlorides contained in applied deicing agents. Basic schemes for preventing the reinforcement corrosion in reinforced-concrete structures have been considered and analyzed. Prospects of primary protection against corrosion of reinforcement by introducing chemical additives with plasticizing/passivating action in a concrete mixture with mixing water have been considered in detail. The physical/chemical mechanism of the protective action of a superplasticizer together with a passivator has been highlighted.

The Use of Natural Pozzolan in Concrete as an Additive or Substitute for Cement

DTIC Science & Technology

2011-12-01

identified opal and chert as the common forms of reactive silica. ERDC/CERL TR-11-46 4 For cracking and expansion to result from the ASR, the following combi...chemical composition of three natural pozzolanic samples was deter- mined through XRD analysis. In addition to these analyses, several addi- tional tests...reflected angle, which results in an inaccurate plot. The correct angle is required to deter- mine the correct composition. A very finely ground sample

Chemically activated manganese dioxide for dry batteries

NASA Astrophysics Data System (ADS)

Askar, M.; Abbas, H.

1994-10-01

The present investigation has enabled us to convert inactive beta-manganese dioxide to high electrochemically active types by chemical processes. Natural and chemically prepared beta-manganese dioxides were roasted at 1050 C to form Mn3O4. This compound was subjected to activation treatment using hydrochloric and sulfuric acid under various reaction conditions. The manganese dioxide so obtained was examined by x-ray diffraction, thermogravimetric, differential thermal, and chemical analyses. The structure of the dioxide obtained was found to be greatly dependent on the origin of MnO2 and type of acid used. Treatment with hydrochloric acid yielded the so-called gamma-variety while sulfuric acid tended to produce gamma- or alpha-MnO2. In addition, waste manganese sulfate obtained as by-product from sulfuric acid digestion treatment was recycled and electrolytically oxidized to gamma-MnO2. The discharge performance of the above-mentioned MnO2 samples as battery cathodic active material was evaluated and compared with the ordinary battery grade.

Extra virgin olive oil bitterness evaluation by sensory and chemical analyses.

PubMed

Favati, Fabio; Condelli, Nicola; Galgano, Fernanda; Caruso, Marisa Carmela

2013-08-15

An experimental investigation was performed on blend extra virgin olive oils (EVOOs) from different cultivars and EVOO from different olive monovarieties (Coratina, Leccino, Maiatica, Ogliarola) with the aim to evaluate the possibility of estimating the perceived bitterness intensity by using chemical indices, such as the total phenol content and the compounds responsible for oil bitterness measured spectrophotometrically at 225 nm (K225 value), as bitterness predictors in different EVOO. Therefore, a bitterness predictive model, based on the relationship between the perceived bitterness intensity of the selected stimuli and the chosen chemicals parameters has been built and validated. The results indicated that the oil bitterness intensity could be satisfactorily predicted by using the K225 values of oil samples. Copyright © 2013 Elsevier Ltd. All rights reserved.

Exploring biological, chemical and geomorphological patterns in fluvial ecosystems with Structural Equation Modelling

NASA Astrophysics Data System (ADS)

Bizzi, S.; Surridge, B.; Lerner, D. N.:

2009-04-01

River ecosystems represent complex networks of interacting biological, chemical and geomorphological processes. These processes generate spatial and temporal patterns in biological, chemical and geomorphological variables, and a growing number of these variables are now being used to characterise the status of rivers. However, integrated analyses of these biological-chemical-geomorphological networks have rarely been undertaken, and as a result our knowledge of the underlying processes and how they generate the resulting patterns remains weak. The apparent complexity of the networks involved, and the lack of coherent datasets, represent two key challenges to such analyses. In this paper we describe the application of a novel technique, Structural Equation Modelling (SEM), to the investigation of biological, chemical and geomorphological data collected from rivers across England and Wales. The SEM approach is a multivariate statistical technique enabling simultaneous examination of direct and indirect relationships across a network of variables. Further, SEM allows a-priori conceptual or theoretical models to be tested against available data. This is a significant departure from the solely exploratory analyses which characterise other multivariate techniques. We took biological, chemical and river habitat survey data collected by the Environment Agency for 400 sites in rivers spread across England and Wales, and created a single, coherent dataset suitable for SEM analyses. Biological data cover benthic macroinvertebrates, chemical data relate to a range of standard parameters (e.g. BOD, dissolved oxygen and phosphate concentration), and geomorphological data cover factors such as river typology, substrate material and degree of physical modification. We developed a number of a-priori conceptual models, reflecting current research questions or existing knowledge, and tested the ability of these conceptual models to explain the variance and covariance within the

Infrared Spectroscopy as a Chemical Fingerprinting Tool

NASA Technical Reports Server (NTRS)

Huff, Tim; Munafo, Paul M. (Technical Monitor)

2002-01-01

Infrared (IR) spectroscopy is a powerful analytical tool in the chemical fingerprinting of materials. The technique is rapid, reproducible and usually non-invasive. With the appropriate accessories, the technique can be used to examine samples in either a solid, liquid or gas phase. Solid samples of varying sizes and shapes may be used, and with the addition of microscopic IR (microspectroscopy) capabilities, minute materials such as single fibers and threads may be examined. With the addition of appropriate software, microspectroscopy can be used for automated discrete point or compositional surface area mapping, with the latter providing a means to record changes in the chemical composition of a material surface over a defined area. Both aqueous and non-aqueous free-flowing solutions can be analyzed using appropriate IR techniques, as can viscous liquids such as heavy oils and greases. Due to the ability to characterize gaseous samples, IR spectroscopy can also be coupled with thermal processes such as thermogravimetric (TG) analyses to provide both thermal and chemical data in a single run. In this configuration, solids (or liquids) heated in a TG analyzer undergo decomposition, with the evolving gases directed into the IR spectrometer. Thus, information is provided on the thermal properties of a material and the order in which its chemical constituents are broken down during incremental heating. Specific examples of these varied applications will be cited, with data interpretation and method limitations further discussed.

Decontamination formulation with sorbent additive

DOEpatents

Tucker; Mark D. , Comstock; Robert H.

2007-10-16

A decontamination formulation and method of making that neutralizes the adverse health effects of both chemical and biological compounds, especially chemical warfare (CW) and biological warfare (BW) agents, and toxic industrial chemicals. The formulation provides solubilizing compounds that serve to effectively render the chemical and biological compounds, particularly CW and BW compounds, susceptible to attack, and at least one reactive compound that serves to attack (and detoxify or kill) the compound. The formulation includes at least one solubilizing agent, a reactive compound, a bleaching activator, a sorbent additive, and water. The highly adsorbent, water-soluble sorbent additive (e.g., sorbitol or mannitol) is used to "dry out" one or more liquid ingredients, such as the liquid bleaching activator (e.g., propylene glycol diacetate or glycerol diacetate) and convert the activator into a dry, free-flowing powder that has an extended shelf life, and is more convenient to handle and mix in the field.

Solar Electric and Chemical Propulsion for a Titan Mission

NASA Technical Reports Server (NTRS)

Cupples, Michael; Green, Shaun E.; Donahue, Benjamin B.; Coverstone, Victoria L.

2005-01-01

Systems analyses were performed for a Titan Explorer Mission characterized by Earth-Saturn transfer stages using solar electric power generation and propulsion systems for primary interplanetary propulsion, and chemical propulsion for capture at Titan. An examination of a range of system factors was performed to determine their effect on the payload delivery capability to Titan. The effect of varying launch vehicle type, solar array power level, ion thruster number, specific impulse, trip time, and Titan capture stage chemical propellant choice was investigated. The major purpose of the study was to demonstrate the efficacy of applying advanced ion propulsion system technologies like NASA's Evolutionary Xenon Thruster (NEXT), coupled with state-of-the-art (SOA) and advanced chemical technologies to a Flagship class mission. This study demonstrated that a NASA Design Reference Mission (DRM) payload of 406 kg could be successfully delivered to Titan using the baseline advanced ion propulsion system in conjunction with SOA chemical propulsion for Titan capture. In addition, the SEPS/Chemical system of this study is compared to an all- chemical NASA DRM mission. Results showed that the NEXT- based SEPS/Chemical system was able to deliver the required payload to Titan in 5 years less transfer time and on a smaller launch vehicle than the SOA chemical option.

Physical, chemical, and biological properties of white MTA with additions of AlF3.

PubMed

Marciano, Marina Angélica; Camilleri, Josette; Lucateli, Ribamar Lazanha; Costa, Reginaldo Mendonça; Matsumoto, Mariza Akemi; Duarte, Marco Antonio Hungaro

2018-04-13

Addition of aluminum fluoride (AlF 3 ) to MTA was tested to inhibit dental discoloration. MTA Angelus with 0, 5, 15, and 45% AlF 3 were tested. The set cements were characterized using scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. Radiopacity and setting time were analyzed according to ANSI/ADA 57 and ASTM C266-08. Volume change was evaluated using volumetric micro-CT analysis. The pH and calcium ion release were assessed after 3 and 24 h and 28 days. Dental discoloration in contact with the cements was assessed after 24 h and 28 and 90 days of contact with bovine and human dentine. Tissue reaction to subcutaneous implantation in rats was examined after 30 and 60 days. AlF 3 altered the microstructure of MTA. The addition of 5% AlF 3 did not significantly alter the radiopacity, setting time, and volume change (p > 0.05). pH and calcium ion release significantly increased with addition of AlF 3 (p > 0.05). All the tested proportions of AlF 3 prevented the dental darkening verified for MTA Angelus in bovine and human teeth. AlF 3 did not interfere in inflammatory response of MTA in all periods of analysis; otherwise, lower amounts showed less intense inflammatory infiltrate. AlF 3 prevents destabilization of bismuth oxide and consequent tooth darkening, frequently verified in clinical practice when using white MTA. The use of 5% of AlF 3 in combination to MTA resulted in a cement that did not result in dental discoloration and did not affect significantly physical, chemical, and biological properties.

Late Chondritic Additions and Planet and Planetesimal Growth: Evaluation of Physical and Chemical Mechanisms

NASA Technical Reports Server (NTRS)

Righter, Kevin

2013-01-01

Studies of terrestrial peridotite and martian and achondritic meteorites have led to the conclusion that addition of chondritic material to growing planets or planetesimals, after core formation, occurred on Earth, Mars, asteroid 4 Vesta, and the parent body of the angritic meteorites [1-4]. One study even proposed that this was a common process in the final stages of growth [5]. These conclusions are based almost entirely on the highly siderophile elements (HSE; Re, Au, Pt, Pd, Rh, Ru, Ir, Os). The HSE are a group of eight elements that have been used to argue for late accretion of chondritic material to the Earth after core formation was complete (e.g., [6]). This idea was originally proposed because the D(metal/silicate) values for the HSE are so high, yet their concentration in the mantle is too high to be consistent with such high Ds. The HSE also are present in chondritic relative abundances and hence require similar Ds if this is the result of core-mantle equilibration. Since the work of [6] there has been a realization that core formation at high PT conditions can explain the abundances of many siderophile elements in the mantle (e.g., [7]), but such detailed high PT partitioning data are lacking for many of the HSE to evaluate whether such ideas are viable for all four bodies. Consideration of other chemical parameters reveals larger problems that are difficult to overcome, but must be addressed in any scenario which calls on the addition of chondritic material to a reduced mantle. Yet these problems are rarely discussed or emphasized, making the late chondritic (or late veneer) addition hypothesis suspect.

Understanding Polycyclic Aromatic Hydrocarbon transfers at the catchment scale combining chemical and fallout radionuclide analyses

NASA Astrophysics Data System (ADS)

Gateuille, D.; Evrard, O.; Lefevre, I.; Moreau-Guigon, E.; Alliot, F.; Chevreuil, M.; Mouchel, J.-M.

2012-04-01

Reducing environmental contamination constitutes a major challenge for industrialized countries. Furthermore, in the European Union, Water Framework Directive (WFD; Directive 2000/60/EC) requires that the member state water bodies reach good ecological and chemical status by 2015. Polycyclic Aromatic Hydrocarbons (PAHs) are a group of persistent organic pollutants considered as priority pollutants because of their mutagenic and carcinogenic properties. They are mostly emitted by human activities such as household heating or road traffic. Although emissions have decreased during the last decades, a large amount of PAHs have been released into the atmosphere for the last two centuries. In recent years, studies dealing with PAHs have grown in number but most of them were restricted to the measurement of PAHs concentrations in the different compartments of the environment (air, soil, sediment, water, etc.). In this context, there remains a lack of knowledge about the transfers and, consequently, about the persistence of these compounds in the environment. This question is particularly acute in the Seine River basin where very high concentrations in PAHs are reported in sediment, thereby compromising the achievement of the good chemical status required by WFD. Our study aims to quantify PAHs transfers at the catchment scale by combining chemical analysis with gamma spectrometry. Atmospheric fallout, soil, river water and sediment samples were collected in two upstream sub-catchments of the Seine River basin during one year. Chemical analyses, restricted to 15 of the 16 PAHs selected by the US Environmental Protection Agency (USEPA), were carried out to determine PAHs concentrations in all samples. Contamination spectra were used to outline the potential origin of pollution. Measurement of fallout radionuclides (Beryllium-7, Lead-210, Caesium-137) in both rainfall and river sediment provided a way to discriminate between freshly eroded sediment vs. material that

Chemical and Sensory Quality Preservation in Coated Almonds with the Addition of Antioxidants.

PubMed

Larrauri, Mariana; Demaría, María Gimena; Ryan, Liliana C; Asensio, Claudia M; Grosso, Nelson R; Nepote, Valeria

2016-01-01

Almonds provide many benefits such as preventing heart disease due to their high content of oleic fatty acid-rich oil and other important nutrients. However, they are susceptible to oxidation reactions causing rancidity during storage. The objective of this work was to evaluate the chemical and sensory quality preservation of almonds coated with carboxymethyl cellulose and with the addition of natural and synthetic antioxidants during storage. Four samples were prepared: almonds without coating (C), almonds coated with carboxymethyl cellulose (CMC), almonds coated with CMC supplemented with peanut skins extract (E), and almonds coated with CMC and supplemented with butylhydroxytoluene (BHT). Proximate composition and fatty acid profile were determined on raw almonds. Almond samples (C, CMC, E and BHT) were stored at 40 °C for 126 d. Lipid oxidation indicators: peroxide value (PV), conjugated dienes (CD), volatile compounds (hexanal and nonanal), and sensory attributes were determined for the stored samples. Samples showed small but significant increases in PV, CD, hexanal and nonanal contents, and intensity ratings of negative sensory attributes (oxidized and cardboard). C had the highest tendency to deterioration during storage. At the end of storage (126 d), C had the highest PV (3.90 meqO2 /kg), and BHT had the lowest PV (2.00 meqO2 /kg). CMC and E samples had similar intermediate PV values (2.69 and 2.57 meqO2 /kg, respectively). CMC coating and the addition of natural (peanut skin extract) and synthetic (BHT) antioxidants provide protection to the roasted almond product. © 2015 Institute of Food Technologists®

Computational Analyses of Complex Flows with Chemical Reactions

NASA Astrophysics Data System (ADS)

Bae, Kang-Sik

The heat and mass transfer phenomena in micro-scale for the mass transfer phenomena on drug in cylindrical matrix system, the simulation of oxygen/drug diffusion in a three dimensional capillary network, and a reduced chemical kinetic modeling of gas turbine combustion for Jet propellant-10 have been studied numerically. For the numerical analysis of the mass transfer phenomena on drug in cylindrical matrix system, the governing equations are derived from the cylindrical matrix systems, Krogh cylinder model, which modeling system is comprised of a capillary to a surrounding cylinder tissue along with the arterial distance to veins. ADI (Alternative Direction Implicit) scheme and Thomas algorithm are applied to solve the nonlinear partial differential equations (PDEs). This study shows that the important factors which have an effect on the drug penetration depth to the tissue are the mass diffusivity and the consumption of relevant species during the time allowed for diffusion to the brain tissue. Also, a computational fluid dynamics (CFD) model has been developed to simulate the blood flow and oxygen/drug diffusion in a three dimensional capillary network, which are satisfied in the physiological range of a typical capillary. A three dimensional geometry has been constructed to replicate the one studied by Secomb et al. (2000), and the computational framework features a non-Newtonian viscosity model for blood, the oxygen transport model including in oxygen-hemoglobin dissociation and wall flux due to tissue absorption, as well as an ability to study the diffusion of drugs and other materials in the capillary streams. Finally, a chemical kinetic mechanism of JP-10 has been compiled and validated for a wide range of combustion regimes, covering pressures of 1atm to 40atm with temperature ranges of 1,200 K--1,700 K, which is being studied as a possible Jet propellant for the Pulse Detonation Engine (PDE) and other high-speed flight applications such as hypersonic

Students' Predictions about the Sensory Properties of Chemical Compounds: Additive versus Emergent Frameworks

ERIC Educational Resources Information Center

Talanquer, Vicente

2008-01-01

We investigated general chemistry students' intuitive ideas about the expected properties of the products of a chemical reaction. In particular, we analyzed college chemistry students' predictions about the color, smell, and taste of the products of chemical reactions represented at the molecular level. The study was designed to explore the extent…

Infrared Spectroscopy as a Chemical Fingerprinting Tool

NASA Technical Reports Server (NTRS)

Huff, Timothy L.

2003-01-01

Infrared (IR) spectroscopy is a powerful analytical tool in the chemical fingerprinting of materials. Any sample material that will interact with infrared light produces a spectrum and, although normally associated with organic materials, inorganic compounds may also be infrared active. The technique is rapid, reproducible and usually non-invasive to the sample. That it is non-invasive allows for additional characterization of the original material using other analytical techniques including thermal analysis and RAMAN spectroscopic techniques. With the appropriate accessories, the technique can be used to examine samples in liquid, solid or gas phase. Both aqueous and non-aqueous free-flowing solutions can be analyzed, as can viscous liquids such as heavy oils and greases. Solid samples of varying sizes and shapes may also be examined and with the addition of microscopic IR (microspectroscopy) capabilities, minute materials such as single fibers and threads may be analyzed. With the addition of appropriate software, microspectroscopy can be used for automated discrete point or compositional surface area mapping, with the latter providing a means to record changes in the chemical composition of a material surface over a defined area. Due to the ability to characterize gaseous samples, IR spectroscopy can also be coupled with thermal processes such as thermogravimetric (TG) analyses to provide both thermal and chemical data in a single run. In this configuration, solids (or liquids) heated in a TG analyzer undergo decomposition, with the evolving gases directed into the IR spectrometer. Thus, information is provided on the thermal properties of a material and the order in which its chemical constituents are broken down during incremental heating. Specific examples of these varied applications will be cited, with data interpretation and method limitations further discussed.

In situ chemical analyses of extraterrestrial bodies

NASA Technical Reports Server (NTRS)

Economou, Thanasis E.; Turkevich, Anthony L.

1988-01-01

One of the most important tasks on any sample return mission will have to be a quick sample characterization in order to guarantee a variety of collected samples. An alpha particle instrument with alpha, proton and X-ray modes can provide a quick and almost complete chemical analysis of Mars samples. This instrument is based on three interactions of the alpha particles from a radioactive source with matter: elastic scattering of the alpha particles by nuclei (alpha mode), (alpha,p) nuclear reaction with some light elements (proton mode), and excitation of the atomic structure of atoms by alpha particles, leading to emission of characteristic X-rays of the lunar surface at three sites during the Surveyor mission of 1967 to 1968. Since then the instrument has been improved and miniaturized substantially. As shown in the past, the alpha particle instrument can operate under Martian conditions without any degradation in the performance. The alpha and proton modes can provide vital information about the light elements, while the X-ray mode with its ambient temperature X-ray detector will be useful for the heavier elements. The excitation of the atomic structure is provided by the same alpha radioactive source that is used by alpha and proton modes or by an auxiliary X-ray source that is selected to enhance the sensitivity to some important geochemical elements.

An analysis of candidates for addition to the Clean Air Act list of hazardous air pollutants.

PubMed

Lunder, Sonya; Woodruff, Tracey J; Axelrad, Daniel A

2004-02-01

There are 188 air toxics listed as hazardous air pollutants (HAPs) in the Clean Air Act (CAA), based on their potential to adversely impact public health. This paper presents several analyses performed to screen potential candidates for addition to the HAPs list. We analyzed 1086 HAPs and potential HAPs, including chemicals regulated by the state of California or with emissions reported to the Toxics Release Inventory (TRI). HAPs and potential HAPs were ranked by their emissions to air, and by toxicity-weighted (tox-wtd) emissions for cancer and noncancer, using emissions information from the TRI and toxicity information from state and federal agencies. Separate consideration was given for persistent, bioaccumulative toxins (PBTs), reproductive or developmental toxins, and chemicals under evaluation for regulation as toxic air contaminants in California. Forty-four pollutants were identified as candidate HAPs based on three ranking analyses and whether they were a PBT or a reproductive or developmental toxin. Of these, nine qualified in two or three different rankings (ammonia [NH3], copper [Cu], Cu compounds, nitric acid [HNO3], N-methyl-2-pyrrolidone, sulfuric acid [H2SO4], vanadium [V] compounds, zinc [Zn], and Zn compounds). This analysis suggests further evaluation of several pollutants for possible addition to the CAA list of HAPs.

Chemical structures and characteristics of animal manures and composts during composting and assessment of maturity indices

PubMed Central

Huang, Jieying; Yu, Zixuan; Gao, Hongjian; Yan, Xiaoming; Chang, Jiang; Wang, Chengming; Hu, Jingwei

2017-01-01

Changes in physicochemical characteristics, chemical structures and maturity of swine, cattle and chicken manures and composts during 70-day composting without addition of bulking agents were investigated. Physicochemical characteristics were measured by routine analyses and chemical structures by solid-state 13C NMR and FT-IR. Three manures were of distinct properties. Their changes in physicochemical characteristics, chemical structures, and maturity were different not only from each other but also from those with addition of bulking agents during composting. Aromaticity in chicken manure composts decreased at first, and then increased whereas that in cattle and swine manure composts increased. Enhanced ammonia volatilization occurred without addition of bulking agents. NMR structural information indicated that cattle and chicken composts were relatively stable at day 36 and 56, respectively, but swine manure composts were not mature up to day 70. Finally, the days required for three manures to reach the threshold values of different maturity indices were different. PMID:28604783

Influence of organic waste and residue mud additions on chemical, physical and microbial properties of bauxite residue sand.

PubMed

Jones, Benjamin E H; Haynes, Richard J; Phillips, Ian R

2011-02-01

In an alumina refinery, bauxite ore is treated with sodium hydroxide at high temperatures and pressures and for every tone of alumina produced, about 2 tones of alkaline, saline bauxite processing waste is also produced. At Alcoa, a dry stacking system of disposal is used, and it is the sand fraction of the processing waste that is rehabilitated. There is little information available regarding the most appropriate amendments to add to the processing sand to aid in revegetation. The purpose of this study was to investigate how the addition of organic wastes (biosolids and poultry manure), in the presence or absence of added residue mud, would affect the properties of the residue sand and its suitability for revegetation. Samples of freshly deposited residue sand were collected from Alcoa's Kwinana refinery. Samples were treated with phosphogypsum (2% v/v), incubated, and leached. A laboratory experiment was then set up in which the two organic wastes were applied at 0 or the equivalent to 60 tones ha(-1) in combination with residue mud added at rates of 0%, 10% and 20% v/v. Samples were incubated for 8 weeks, after which, key chemical, physical and microbial properties of the residue sand were measured along with seed germination. Additions of residue mud increased exchangeable Na(+), ESP and the pH, and HCO (3) (-) and Na(+) concentrations in saturation paste extracts. Additions of biosolids and poultry manure increased concentrations of extractable P, NH (4) (+) , K, Mg, Cu, Zn, Mn and Fe. Addition of residue mud, in combination with organic wastes, caused a marked decrease in macroporosity and a concomitant increase in mesoporosity, available water holding capacity and the quantity of water held at field capacity. With increasing residue mud additions, the percentage of sample present as sand particles (<1 mm diameter) decreased, and the percentage present in aggregated form (>2 mm diameter) increased; greatest aggregation occurred where a combination of residue

Quantification of chemical contaminants in the paper and board fractions of municipal solid waste.

PubMed

Pivnenko, K; Olsson, M E; Götze, R; Eriksson, E; Astrup, T F

2016-05-01

Chemicals are used in materials as additives in order to improve the performance of the material or the production process itself. The presence of these chemicals in recyclable waste materials may potentially affect the recyclability of the materials. The addition of chemicals may vary depending on the production technology or the potential end-use of the material. Paper has been previously shown to potentially contain a large variety of chemicals. Quantitative data on the presence of chemicals in paper are necessary for appropriate waste paper management, including the recycling and re-processing of paper. However, a lack of quantitative data on the presence of chemicals in paper is evident in the literature. The aim of the present work is to quantify the presence of selected chemicals in waste paper derived from households. Samples of paper and board were collected from Danish households, including both residual and source-segregated materials, which were disposed of (e.g., through incineration) and recycled, respectively. The concentration of selected chemicals was quantified for all of the samples. The quantified chemicals included mineral oil hydrocarbons, phthalates, phenols, polychlorinated biphenyls, and selected toxic metals (Cd, Co, Cr, Cu, Ni, and Pb). The results suggest large variations in the concentration of chemicals depending on the waste paper fraction analysed. Research on the fate of chemicals in waste recycling and potential problem mitigation measures should be focused on in further studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Toxicity and chemical analyses of airport runoff waters in Poland.

PubMed

Sulej, Anna Maria; Polkowska, Zaneta; Wolska, Lidia; Cieszynska, Monika; Namieśnik, Jacek

2014-05-01

The aim of this study was to assess the ecotoxicological effects of various compounds in complex airport effluents using a chemical and ecotoxicological integrated strategy. The present work deals with the determination of sum of PCBs, PAHs, pesticides, cations, anions, phenols, anionic, cationic, non-ionic detergents, formaldehyde and metals--as well as TOC and conductivity--in runoff water samples collected from 2009 to 2011 at several locations on two Polish international airports. Two microbiotests (Vibrio fischeri bacteria and the crustacean Thamnocephalus platyurus) have been used to determine the ecotoxicity of airport runoff waters. The levels of many compounds exceeded several or even several tens of times the maximum permissible levels. Analysis of the obtained data shows that samples that displayed maximum toxicity towards the bioindicators Vibrio fischeri were not toxic towards Thamnocephalus platyurus. Levels of toxicity towards T. platyurus are strongly correlated with pollutants that originate from the technological operations related to the maintenance of airport infrastructure. The integrated (chemical-ecotoxicological) approach to environmental contamination assessment in and around airports yields extensive information on the quality of the environment. These methodologies can be then used as tools for tracking the environmental fate of these compounds and for assessing the environmental effect of airports. Subsequently, these data will provide a basis for airport infrastructure management.

Concentration Addition, Independent Action and Generalized Concentration Addition Models for Mixture Effect Prediction of Sex Hormone Synthesis In Vitro

PubMed Central

Hadrup, Niels; Taxvig, Camilla; Pedersen, Mikael; Nellemann, Christine; Hass, Ulla; Vinggaard, Anne Marie

2013-01-01

Humans are concomitantly exposed to numerous chemicals. An infinite number of combinations and doses thereof can be imagined. For toxicological risk assessment the mathematical prediction of mixture effects, using knowledge on single chemicals, is therefore desirable. We investigated pros and cons of the concentration addition (CA), independent action (IA) and generalized concentration addition (GCA) models. First we measured effects of single chemicals and mixtures thereof on steroid synthesis in H295R cells. Then single chemical data were applied to the models; predictions of mixture effects were calculated and compared to the experimental mixture data. Mixture 1 contained environmental chemicals adjusted in ratio according to human exposure levels. Mixture 2 was a potency adjusted mixture containing five pesticides. Prediction of testosterone effects coincided with the experimental Mixture 1 data. In contrast, antagonism was observed for effects of Mixture 2 on this hormone. The mixtures contained chemicals exerting only limited maximal effects. This hampered prediction by the CA and IA models, whereas the GCA model could be used to predict a full dose response curve. Regarding effects on progesterone and estradiol, some chemicals were having stimulatory effects whereas others had inhibitory effects. The three models were not applicable in this situation and no predictions could be performed. Finally, the expected contributions of single chemicals to the mixture effects were calculated. Prochloraz was the predominant but not sole driver of the mixtures, suggesting that one chemical alone was not responsible for the mixture effects. In conclusion, the GCA model seemed to be superior to the CA and IA models for the prediction of testosterone effects. A situation with chemicals exerting opposing effects, for which the models could not be applied, was identified. In addition, the data indicate that in non-potency adjusted mixtures the effects cannot always be

Sustainable nutrients recovery and recycling by optimizing the chemical addition sequence for struvite precipitation from raw swine slurries.

PubMed

Taddeo, Raffaele; Kolppo, Kari; Lepistö, Raghida

2016-09-15

Livestock farming contributes heavily to nitrogen (N) and phosphorus (P) flows into the environment, a major cause of eutrophication of coastal and freshwater systems. Furthermore, the growing demand for N-P fertilizers is increasing the emission of anthropogenic reactive N into the atmosphere and the depletion of the current P reserves. Therefore, it is essential to minimize the anthropogenic impact on the environment and recycle the wasted N-P for agricultural reuse. This study focused on enhancing struvite (MgNH4PO4*6H2O) precipitation from raw swine slurries in batch and laboratory-scale reactors. Different chemical addition sequences were evaluated, and the best removal efficiency (E%) was obtained when the chemicals were mixed before the precipitation process. Struvite was detected at a pH as low as 6 (E%N-P∼50%), and high E%N-P was found at pH 7-9.5 (80-95%). Furthermore, air stripping was used in place of NaOH to adjust pH, returning the same efficiency as if only alkali had been used. XRD and FE-SEM analysis of the precipitate showed that the recovered struvite was of high purity with orthorhombic crystalline structure and only trace amounts of impurities from matrix organics, co-precipitation products (CaO and amorphous calcium-phosphates), and residuals of added chemicals (MgO). Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessment of Weighted Quantile Sum Regression for Modeling Chemical Mixtures and Cancer Risk

PubMed Central

Czarnota, Jenna; Gennings, Chris; Wheeler, David C

2015-01-01

In evaluation of cancer risk related to environmental chemical exposures, the effect of many chemicals on disease is ultimately of interest. However, because of potentially strong correlations among chemicals that occur together, traditional regression methods suffer from collinearity effects, including regression coefficient sign reversal and variance inflation. In addition, penalized regression methods designed to remediate collinearity may have limitations in selecting the truly bad actors among many correlated components. The recently proposed method of weighted quantile sum (WQS) regression attempts to overcome these problems by estimating a body burden index, which identifies important chemicals in a mixture of correlated environmental chemicals. Our focus was on assessing through simulation studies the accuracy of WQS regression in detecting subsets of chemicals associated with health outcomes (binary and continuous) in site-specific analyses and in non-site-specific analyses. We also evaluated the performance of the penalized regression methods of lasso, adaptive lasso, and elastic net in correctly classifying chemicals as bad actors or unrelated to the outcome. We based the simulation study on data from the National Cancer Institute Surveillance Epidemiology and End Results Program (NCI-SEER) case–control study of non-Hodgkin lymphoma (NHL) to achieve realistic exposure situations. Our results showed that WQS regression had good sensitivity and specificity across a variety of conditions considered in this study. The shrinkage methods had a tendency to incorrectly identify a large number of components, especially in the case of strong association with the outcome. PMID:26005323

Assessment of weighted quantile sum regression for modeling chemical mixtures and cancer risk.

PubMed

Czarnota, Jenna; Gennings, Chris; Wheeler, David C

2015-01-01

In evaluation of cancer risk related to environmental chemical exposures, the effect of many chemicals on disease is ultimately of interest. However, because of potentially strong correlations among chemicals that occur together, traditional regression methods suffer from collinearity effects, including regression coefficient sign reversal and variance inflation. In addition, penalized regression methods designed to remediate collinearity may have limitations in selecting the truly bad actors among many correlated components. The recently proposed method of weighted quantile sum (WQS) regression attempts to overcome these problems by estimating a body burden index, which identifies important chemicals in a mixture of correlated environmental chemicals. Our focus was on assessing through simulation studies the accuracy of WQS regression in detecting subsets of chemicals associated with health outcomes (binary and continuous) in site-specific analyses and in non-site-specific analyses. We also evaluated the performance of the penalized regression methods of lasso, adaptive lasso, and elastic net in correctly classifying chemicals as bad actors or unrelated to the outcome. We based the simulation study on data from the National Cancer Institute Surveillance Epidemiology and End Results Program (NCI-SEER) case-control study of non-Hodgkin lymphoma (NHL) to achieve realistic exposure situations. Our results showed that WQS regression had good sensitivity and specificity across a variety of conditions considered in this study. The shrinkage methods had a tendency to incorrectly identify a large number of components, especially in the case of strong association with the outcome.

SIMS analyses of minor and trace element distributions in fracture calcite from Yucca Mountain, Nevada, USA

NASA Astrophysics Data System (ADS)

Denniston, Rhawn F.; Shearer, Charles K.; Layne, Graham D.; Vaniman, David T.

1997-05-01

Fracture-lining calcite samples from Yucca Mountain, Nevada, obtained as part of the extensive vertical sampling in studies of this site as a potential high-level waste repository, have been characterized according to microbeam-scale (25-30 μm) trace and minor element chemistry, and cathodoluminescent zonation patterns. As bulk chemical analyses are limited in spatial resolution and are subject to contamination by intergrown phases, a technique for analysis by secondary ion mass spectrometry (SIMS) of minor (Mn, Fe, Sr) and trace (REE) elements in calcite was developed and applied to eighteen calcite samples from four boreholes and one trench. SIMS analyses of REE in calcite and dolomite have been shown to be quantitative to abundances < 1 × chondrite. Although the low secondary ion yields associated with carbonates forced higher counting times than is necessary in most silicates, Mn, Fe, Sr, and REE analyses were obtained with sub-ppm detection limits and 2-15% analytical precision. Bulk chemical signatures noted by Vaniman (1994) allowed correlation of minor and trace element signatures in Yucca Mountain calcite with location of calcite precipitation (saturated vs. unsaturated zone). For example, upper unsaturated zone calcite exhibits pronounced negative Ce and Eu anomalies not observed in calcite collected below in the deep unsaturated zone. These chemical distinctions served as fingerprints which were applied to growth zones in order to examine temporal changes in calcite crystallization histories; analyses of such fine-scale zonal variations are unattainable using bulk analytical techniques. In addition, LREE (particularly Ce) scavenging of calcite-precipitating solutions by manganese oxide phases is discussed as the mechanism for Ce-depletion in unsaturated zone calcite.

Tafamidis delays disease progression in patients with early stage transthyretin familial amyloid polyneuropathy: additional supportive analyses from the pivotal trial.

PubMed

Keohane, Denis; Schwartz, Jeffrey; Gundapaneni, Balarama; Stewart, Michelle; Amass, Leslie

2017-03-01

Tafamidis, a non-NSAID highly specific transthyretin stabilizer, delayed neurologic disease progression as measured by Neuropathy Impairment Score-Lower Limbs (NIS-LL) in an 18-month, double-blind, placebo-controlled randomized trial in 128 patients with early-stage transthyretin V30M familial amyloid polyneuropathy (ATTRV30M-FAP). The current post hoc analyses aimed to further evaluate the effects of tafamidis in delaying ATTRV30M-FAP progression in this trial. Pre-specified, repeated-measures analysis of change from baseline in NIS-LL in this trial (ClinicalTrials.gov NCT00409175) was repeated with addition of baseline as covariate and multiple imputation analysis for missing data by treatment group. Change in NIS-LL plus three small-fiber nerve tests (NIS-LL + Σ3) and NIS-LL plus seven nerve tests (NIS-LL + Σ7) were assessed without baseline as covariate. Treatment outcomes over the NIS-LL, Σ3, Σ7, modified body mass index and Norfolk Quality of Life-Diabetic Neuropathy Total Quality of Life Score were also examined using multivariate analysis techniques. Neuropathy progression based on NIS-LL change from baseline to Month 18 remained significantly reduced for tafamidis versus placebo in the baseline-adjusted and multiple imputation analyses. NIS-LL + Σ3 and NIS-LL + Σ7 captured significant treatment group differences. Multivariate analyses provided strong statistical evidence for a superior tafamidis treatment effect. These supportive analyses confirm that tafamidis delays neurologic progression in early-stage ATTRV30M-FAP. NCT00409175.

Hair analyses: worthless for vitamins, limited for minerals.

PubMed

Hambidge, K M

1982-11-01

Despite many major and minor problems with interpretation of analytical data, chemical analyses of human hair have some potential value. Extensive research will be necessary to define this value, including correlation of hair concentrations of specific elements with those in other tissues and metabolic pools and definition of normal physiological concentration ranges. Many factors that may compromise the correct interpretation of analytical data require detailed evaluation for each specific element. Meanwhile, hair analyses are of some value in the comparison of different populations and, for example, in public health community surveys of environmental exposure to heavy metals. On an individual basis, their established usefulness is much more restricted and the limitations are especially notable for evaluation of mineral nutritional status. There is a wide gulf between the limited and mainly tentative scientific justification for their use on an individual basis and the current exploitation of multielement chemical analyses of human hair.

Transformation of oil palm fronds into pentose sugars using copper (II) sulfate pentahydrate with the assistance of chemical additive.

PubMed

Loow, Yu-Loong; Wu, Ta Yeong

2018-06-15

Among the chemical pretreatments available for pretreating biomass, the inorganic salt is considered to be a relatively new but simple reagent that offers comparable pentose (C5) sugar recoveries as the conventional dilute acid hydrolysis. This study investigated the effects of different concentrations (1.5-6.0% (v/v)) of H 2 O 2 or Na 2 S 2 O 8 in facilitating CuSO 4 ·5H 2 O pretreatment for improving pentose sugar recovery from oil palm fronds. The best result was observed when 0.2 mol/L of CuSO 4 ·5H 2 O was integrated with 4.5% (v/v) of Na 2 S 2 O 8 to recover 8.2 and 0.9 g/L of monomeric xylose and arabinose, respectively in the liquid fraction. On the other hand, an addition of 1.5% (v/v) of H 2 O 2 yielded approximately 74% lesser total pentose sugars as compared to using 4.5% (v/v) Na 2 S 2 O 8 . By using CuSO 4 ·5H 2 O alone (control), only 0.8 and 1.0 g/L xylose and arabinose, respectively could be achieved. The results mirrored the importance of using chemical additives together with the inorganic salt pretreatment of oil palm fronds. Thus, an addition of 4.5% (v/v) of Na 2 S 2 O 8 during CuSO 4 ·5H 2 O pretreatment of oil palm fronds at 120 °C and 30 min was able to attain a total pentose sugar yield up to ∼40%. Copyright © 2017 Elsevier Ltd. All rights reserved.

Innovative Additive for Bitumen Based on Processed Fats

NASA Astrophysics Data System (ADS)

Babiak, Michał; Kosno, Jacek; Ratajczak, Maria; Zieliński, Krzysztof

2017-10-01

Various additives, admixtures and modifiers are used to improve technical properties and strength characteristics of building materials. Manufacturers of waterproofing materials, concrete, ceramics and bitumen have to use innovative, increasingly complex and costly additives, admixtures or modifiers. As a result, simple and inexpensive substances have been replaced by complex, long chain polymers, multi component resins or plastics. For economic and ecological reasons waste materials are more frequently used as additives, admixtures and modifiers. Nowadays the most commonly used physical modifiers of bitumen belong to the group of polymers - large molecular organic compounds of natural origin or being the result of planned chemical synthesis. Polymers are substances that do not chemically react with bitumen, they act as fillers or create a spatial network within bitumen (the so called physical cross-linking). The development of organic chemistry has allowed the synthesis of a number of substances chemically modifying bitumen. The most promising are heterocyclic organic compounds belonging to the group of imidazolines. The aim of the study presented in this paper was to demonstrate the suitability of processed natural and post-refining fat waste (diamidoamine dehydrate) as bitumen modifier. This paper discusses the impact of adding technical imidazoline on selected bitumen characteristics. Samples of bitumen 160/220, which is most commonly used for the production of waterproofing products, were analysed. For base bitumen and bitumen modified with technical imidazoline the following measurements were taken: measurement of the softening point by Ball and Ring method, determination of the breaking point by Fraass method and needle penetration measurement at 25°C. Later the samples were aged using TFOT laboratory method and the basic characteristics were determined again. The results showed that a small amount of imidazoline improved bitumen thermoplastic parameters at

Hazardous organic chemicals in rubber recycled tire playgrounds and pavers.

PubMed

Llompart, Maria; Sanchez-Prado, Lucia; Pablo Lamas, J; Garcia-Jares, Carmen; Roca, Enrique; Dagnac, Thierry

2013-01-01

In this study, the presence of hazardous organic chemicals in surfaces containing recycled rubber tires is investigated. Direct material analyses using solvent extraction, as well as SPME analysis of the vapour phase above the sample, were carried out. Twenty-one rubber mulch samples were collected from nine different playgrounds. In addition, seven commercial samples of recycled rubber pavers were acquired in a local store of a multinational company. All samples were extracted by ultrasound energy, followed by analysis of the extract by GC-MS. The analysis confirmed the presence of a large number of hazardous substances including PAHs, phthalates, antioxidants (e.g. BHT, phenols), benzothiazole and derivatives, among other chemicals. The study evidences the high content of toxic chemicals in these recycled materials. The concentration of PAHs in the commercial pavers was extremely high, reaching values up to 1%. In addition, SPME studies of the vapour phase above the samples confirm the volatilisation of many of those organic compounds. Uses of recycled rubber tires, especially those targeting play areas and other facilities for children, should be a matter of regulatory concern. Copyright © 2012 Elsevier Ltd. All rights reserved.

Applying Data Mining Techniques to Chemical Analyses of Pre-drill Groundwater Samples within the Marcellus Formation Shale Play in Bradford County, Pennsylvania

NASA Astrophysics Data System (ADS)

Wen, T.; Niu, X.; Gonzales, M. S.; Li, Z.; Brantley, S.

2017-12-01

Groundwater samples are collected for chemical analyses by shale gas industry consultants in the vicinity of proposed gas wells in Pennsylvania. These data sets are archived so that the chemistry of water from homeowner wells can be compared to chemistry after gas-well drilling. Improved public awareness of groundwater quality issues will contribute to designing strategies for both water resource management and hydrocarbon exploration. We have received water analyses for 11,000 groundwater samples from PA Department of Environmental Protection (PA DEP) in the Marcellus Shale footprint in Bradford County, PA for the years ranging from 2010 to 2016. The PA DEP has investigated these analyses to determine whether gas well drilling or other activities affected water quality. We are currently investigating these analyses to look for patterns in chemistry throughout the study area (related or unrelated to gas drilling activities) and to look for evidence of analytes that may be present at concentrations higher than the advised standards for drinking water. Our preliminary results reveal that dissolved methane concentrations tend to be higher along fault lines in Bradford County [1]. Lead (Pb), arsenic (As), and barium (Ba) are sometimes present at levels above the EPA maximum contaminant level (MCL). Iron (Fe) and manganese (Mn) more frequently violate the EPA standard. We find that concentrations of some chemical analytes (e.g., Ba and Mn) are dependent on bedrock formations (i.e., Catskill vs. Lock Haven) while concentrations of other analytes (e.g., Pb) are not statistically significantly distinct between different bedrock formations. Our investigations are also focused on looking for correlations that might explain water quality patterns with respect to human activities such as gas drilling. However, percentages of water samples failing EPA MCL with respect to Pb, As, and Ba have decreased from previous USGS and PSU studies in the 1990s and 2000s. Public access to

Evaluation of toxicity and estrogenicity of the landfill-concentrated leachate during advanced oxidation treatment: chemical analyses and bioanalytical tools.

PubMed

Wang, Guifang; Lu, Gang; Zhao, Jiandi; Yin, Pinghe; Zhao, Ling

2016-08-01

Landfill-concentrated leachate from membrane separation processes is a potential pollution source for the surroundings. In this study, the toxicity and estrogenicity potentials of concentrated leachate prior to and during UV-Fenton and Fenton treatments were assessed by a combination of chemical (di (2-ethylhexyl) phthalate and dibutyl phthalate were chosen as targets) and biological (Daphnia magna, Chlorella vulgaris, and E-screen assay) analyses. Removal efficiencies of measured di (2-ethylhexyl) phthalate and dibutyl phthalate were more than 97 % after treatment with the two methods. Biological tests showed acute toxicity effects on D. magna tests in untreated concentrated leachate samples, whereas acute toxicity on C. vulgaris tests was not observed. Both treatment methods were found to be efficient in reducing acute toxicity effects on D. magna tests. The E-screen test showed concentrated leachate had significant estrogenicity, UV-Fenton and Fenton treatment, especially the former, were effective methods for reducing estrogenicity of concentrated leachate. The EEQchem (estradiol equivalent concentration) of all samples could only explain 0.218-5.31 % range of the EEQbio. These results showed that UV-Fenton reagent could be considered as a suitable method for treatment of concentrated leachate, and the importance of the application of an integrated (biological + chemical) analytical approach for a comprehensive evaluation of treatment suitability.

Assessing the effects of adsorptive polymeric resin additions on fungal secondary metabolite chemical diversity.

PubMed

González-Menéndez, Víctor; Asensio, Francisco; Moreno, Catalina; de Pedro, Nuria; Monteiro, Maria Candida; de la Cruz, Mercedes; Vicente, Francisca; Bills, Gerald F; Reyes, Fernando; Genilloud, Olga; Tormo, José R

2014-07-03

Adsorptive polymeric resins have been occasionally described to enhance the production of specific secondary metabolites (SMs) of interest. Methods that induce the expression of new chemical entities in fungal fermentations may lead to the discovery of new bioactive molecules and should be addressed as possible tools for the creation of new microbial chemical libraries for drug lead discovery. Herein, we apply both biological activity and chemical evaluations to assess the use of adsorptive resins as tools for the differential expression of SMs in fungal strain sets. Data automation approaches were applied to ultra high performance liquid chromatography analysis of extracts to evaluate the general influence in generating new chemical entities or in changing the production of specific SMs by fungi grown in the presence of resins and different base media.

Additive effects on the androgen signaling pathway by chemicals with different modes of action-COW2015

EPA Science Inventory

Risk assessments have traditionally been developed on a chemical-by-chemical basis. However, regulatory agencies recently have been considering cumulative effects of chemicals that act via a common mechanism of toxicity. Here we present data on several mixture studies of chemic...

24 CFR 81.65 - Other information and analyses.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Other information and analyses. 81... information and analyses. When deemed appropriate and requested in writing, on a case by-case basis, by the... conduct additional analyses concerning any such report. A GSE shall submit additional reports or other...

24 CFR 81.65 - Other information and analyses.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 24 Housing and Urban Development 1 2012-04-01 2012-04-01 false Other information and analyses. 81... information and analyses. When deemed appropriate and requested in writing, on a case by-case basis, by the... conduct additional analyses concerning any such report. A GSE shall submit additional reports or other...

24 CFR 81.65 - Other information and analyses.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false Other information and analyses. 81... information and analyses. When deemed appropriate and requested in writing, on a case by-case basis, by the... conduct additional analyses concerning any such report. A GSE shall submit additional reports or other...

24 CFR 81.65 - Other information and analyses.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 24 Housing and Urban Development 1 2014-04-01 2014-04-01 false Other information and analyses. 81... information and analyses. When deemed appropriate and requested in writing, on a case by-case basis, by the... conduct additional analyses concerning any such report. A GSE shall submit additional reports or other...

24 CFR 81.65 - Other information and analyses.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 24 Housing and Urban Development 1 2013-04-01 2013-04-01 false Other information and analyses. 81... information and analyses. When deemed appropriate and requested in writing, on a case by-case basis, by the... conduct additional analyses concerning any such report. A GSE shall submit additional reports or other...

How many food additives are rodent carcinogens?

PubMed

Johnson, F M

2002-01-01

One generally assumes that chemical agents added to foods are reasonably free of risks to human health, and practically everyone consumes some additives in his or her food daily throughout life. In the United States, the 1958 Food Additives Amendment to the Federal Food, Drug and Cosmetic Act of 1938 requires food manufacturers to demonstrate the safety of food additives to the Food and Drug Administration (FDA). The Amendment contains a provision that prohibits approval of an additive if it is found to cause cancer in humans or animals. In the present study, data from the National Toxicology Program rodent bioassay (NTPRB) were used to identify a sample of approximately 50 rodent-tested additives and other chemicals added to food that had been evaluated independently of the FDA/food industry. Surprisingly, the sample shows more than 40% of these food chemicals to be carcinogenic in one or more rodent groups. If this percentage is extrapolated to all substances added to food in the United States, it would imply that more than 1000 of such substances are potential rodent carcinogens. The NTP and FDA test guidelines use similar, though not necessarily identical, rodent test procedures, including near lifetime exposures to the maximum tolerated dose. The FDA specifies that test chemicals should be administered by the oral route. However, the oral route includes three methods of delivering chemicals, that is, mixed in the food or water or delivered by stomach tube (gavage). The NTP data show only 1 of 18 food chemicals mixed in the food are rodent carcinogens, but 16 of 23 gavage-administered food chemicals are carcinogenic to rodents. The distribution suggests that among orally delivered chemicals, those administered in the feed will more likely prove to be noncarcinogens than chemicals given by gavage. The rodent data also reveal that effects may vary according to dose and genotype, as well as by route of administration, to further complicate extrapolation to humans

Sampling and physico-chemical analysis of precipitation: a review.

PubMed

Krupa, Sagar V

2002-01-01

Wet deposition is one of two processes governing the transfer of beneficial and toxic chemicals from the atmosphere on to surfaces. Since the early 1970s, numerous investigators have sampled and analyzed precipitation for their chemical constituents, in the context of "acidic rain" and related atmospheric processes. Since then, significant advances have been made in our understanding of how to sample rain, cloud and fog water to preserve their physico-chemical integrity prior to analyses. Since the 1970s large-scale precipitation sampling networks have been in operation to broadly address regional and multi-regional issues. However, in examining the results from such efforts at a site-specific level, concerns have been raised about the accuracy and precision of the information gathered. There is mounting evidence to demonstrate the instability of precipitation samples (e.g. with N species) that have been subjected to prolonged ambient or field conditions. At the present time precipitation sampling procedures allow unrefrigerated or refrigerated collection of wet deposition from individual events, sequential fractions within events, in situ continuous chemical analyses in the field and even sampling of single or individual rain, cloud and fog droplets. Similarly analytical procedures of precipitation composition have advanced from time-consuming methods to rapid and simultaneous analyses of major anions and cations, from bulk samples to single droplets. For example, analytical techniques have evolved from colorimetry to ion chromatography to capillary electrophoresis. Overall, these advances allow a better understanding of heterogeneous reactions and atmospheric pollutant scavenging processes by precipitation. In addition, from an environmental perspective, these advances allow better quantification of semi-labile (e.g. NH4+, frequently its deposition values are underestimated) or labile species [e.g. S (IV)] in precipitation and measurements of toxic chemicals such

Evaluation of antistripping additives.

DOT National Transportation Integrated Search

1989-01-01

Several chemical antistripping additives were used in field installations and compared to a similar installation using hydrated lime. The performance of the installations was monitored periodically, and material that was sampled during construction w...

The effects of chemical additives on the production of disinfection byproducts and ecotoxicity in simulated ballast water

NASA Astrophysics Data System (ADS)

Park, Chul; Cha, Hyung-Gon; Lee, Ji-Hyun; Choi, Tae Seop; Lee, Jungsuk; Kim, Young-Hee; Bae, Minjung; Shin, Kyoungsoon; Choi, Keun-Hyung

2017-11-01

The management of ship ballast water is essential to stemming the introduction of non-indigenous species. Approval for onboard installation of a system to treat ballast water requires rigorous land-based testing as dictated in the G8 guideline by the International Maritime Organization. However, this testing lacks standardization-most notably augmentation of organic carbon for influent water by adding chemical additives. Electrochlorination is a popular treatment method for ballast water, in which chlorinated oxidants react with organisms and organic matter in water. The additives could thus affect the treatment efficacy of the ballast water. Here, we examined the effects of several candidates of organic carbon additives on the consumption of total residual oxidant (TRO), the production of disinfection byproducts (DBPs), plankton survival, and ecotoxicity. The TRO consumption over five days of storage was higher in electrochlorinated seawater amended with lignin and Metamucil when compared with seawaters with other organic carbon compounds. DBP production varied by almost two orders of magnitude as a function of the various additives. This was largely attributed to the production of tribromomethane and dibromoacetic acid. The survival of Artemia franciscana was significantly different across waters of different organic carbon additives. Algal toxicity testing with the marine haptophyte Isochrysis galbana significantly reduced growth in lignin- and Metamucil-treated seawaters, but not with other organic carbon compounds. Bioluminescence in Vibrio fischeri sharply declined in electrochlorinated seawaters with all types of organic carbon compounds, but no toxicity was manifested once the electrochlorinated seawaters were neutralized with sodium thiosulfate. The varying degrees of outcome suggest that it might be better to eliminate the requirements of adding organic carbon to test water as long as natural water was used for land-based testing of BWMS. If needed, the

Sampling and Chemical Analysis of Potable Water for ISS Expeditions 12 and 13

NASA Technical Reports Server (NTRS)

Straub, John E. II; Plumlee, Deborah K.; Schultz, John R.

2007-01-01

The crews of Expeditions 12 and 13 aboard the International Space Station (ISS) continued to rely on potable water from two different sources, regenerated humidity condensate and Russian ground-supplied water. The Space Shuttle launched twice during the 12- months spanning both expeditions and docked with the ISS for delivery of hardware and supplies. However, no Shuttle potable water was transferred to the station during either of these missions. The chemical quality of the ISS onboard potable water supplies was verified by performing ground analyses of archival water samples at the Johnson Space Center (JSC) Water and Food Analytical Laboratory (WAFAL). Since no Shuttle flights launched during Expedition 12 and there was restricted return volume on the Russian Soyuz vehicle, only one chemical archive potable water sample was collected with U.S. hardware and returned during Expedition 12. This sample was collected in March 2006 and returned on Soyuz 11. The number and sensitivity of the chemical analyses performed on this sample were limited due to low sample volume. Shuttle flights STS-121 (ULF1.1) and STS-115 (12A) docked with the ISS in July and September of 2006, respectively. These flights returned to Earth with eight chemical archive potable water samples that were collected with U.S. hardware during Expedition 13. The average collected volume increased for these samples, allowing full chemical characterization to be performed. This paper presents a discussion of the results from chemical analyses performed on Expeditions 12 and 13 archive potable water samples. In addition to the results from the U.S. samples analyzed, results from pre-flight samples of Russian potable water delivered to the ISS on Progress vehicles and in-flight samples collected with Russian hardware during Expeditions 12 and 13 and analyzed at JSC are also discussed.

Quantum chemical investigation of levofloxacin-boron complexes: A computational approach

NASA Astrophysics Data System (ADS)

Sayin, Koray; Karakaş, Duran

2018-04-01

Quantum chemical calculations are performed over some boron complexes with levofloxacin. Boron complex with fluorine atoms are optimized at three different methods (HF, B3LYP and M062X) with 6-31 + G(d) basis set. The best level is determined as M062X/6-31 + G(d) by comparison of experimental and calculated results of complex (1). The other complexes are optimized by using the best level. Structural properties, IR and NMR spectrum are examined in detail. Biological activities of mentioned complexes are investigated by some quantum chemical descriptors and molecular docking analyses. As a result, biological activities of complex (2) and (4) are close to each other and higher than those of other complexes. Additionally, NLO properties of mentioned complexes are investigated by some quantum chemical parameters. It is found that complex (3) is the best candidate for NLO applications.

Mechanism of action of additives in chemical vapor generation of hydrogen selenide: Iodide and thiocyanate

NASA Astrophysics Data System (ADS)

Pitzalis, Emanuela; Onor, Massimo; Spiniello, Roberto; Braz, Carlos Eduardo Mendes; D'Ulivo, Alessandro

2018-07-01

The chemical vapor generation of H2Se has been investigated in the presence and in the absence of either NaI or NaSCN as additives (0.5 mol L-1), in HClO4 media (0.1-5.0 mol L-1) and using a low concentration of NaBH4 (0.02 mol L-1). The enhancement of generation efficiency of H2Se produced by iodide and thiocyanate was measured by a continuous flow reaction system coupled with a miniature argon‑hydrogen diffusion flame and atomic absorption detection. The chemifold of the continuous flow reactor was designed in order to change the mixing sequence and the interaction time of the reagents. By this way it has been possible to evaluate the contribution of additive‑selenium and additive-borane species to the mechanism producing the increase of generation efficiency of H2Se. Both the iodide complexes of selenium and borane contribute to enhance generation efficiency of H2Se, whereas the thiocyanate complexes of selenium rather than thiocyanate-borane complexes play a major role in the enhancement of the efficiency. At elevated acidities (2 < [H+] < 5 mol L-1), only thiocyanate continues to maintain its properties to increase H2Se generation efficiency while iodide causes a marked signal depression unless its addition is performed after the starting of SeIV- [BH4-] reaction with an appropriate time delay. Both iodide and thiocyanate caused marked depression of H2Se generation when NaBH4 was replaced by the amine boranes, NH3-BH3 and tert-ButylNH2-BH3.

15 CFR 714.3 - Advance declaration requirements for additionally planned production of Schedule 3 chemicals.

Code of Federal Regulations, 2013 CFR

2013-01-01

... a Schedule 3 chemical above the declaration threshold; (ii) You plan to produce at a plant declared...; (iii) You plan to increase the production of a Schedule 3 chemical by declared plants on your plant... production of a Schedule 3 chemical at a declared plant site to an amount above the upper limit of the range...

15 CFR 714.3 - Advance declaration requirements for additionally planned production of Schedule 3 chemicals.

Code of Federal Regulations, 2012 CFR

2012-01-01

... a Schedule 3 chemical above the declaration threshold; (ii) You plan to produce at a plant declared...; (iii) You plan to increase the production of a Schedule 3 chemical by declared plants on your plant... production of a Schedule 3 chemical at a declared plant site to an amount above the upper limit of the range...

15 CFR 714.3 - Advance declaration requirements for additionally planned production of Schedule 3 chemicals.

Code of Federal Regulations, 2014 CFR

2014-01-01

... a Schedule 3 chemical above the declaration threshold; (ii) You plan to produce at a plant declared...; (iii) You plan to increase the production of a Schedule 3 chemical by declared plants on your plant... production of a Schedule 3 chemical at a declared plant site to an amount above the upper limit of the range...

The quantitative surface analysis of an antioxidant additive in a lubricant oil matrix by desorption electrospray ionization mass spectrometry

PubMed Central

Da Costa, Caitlyn; Reynolds, James C; Whitmarsh, Samuel; Lynch, Tom; Creaser, Colin S

2013-01-01

RATIONALE Chemical additives are incorporated into commercial lubricant oils to modify the physical and chemical properties of the lubricant. The quantitative analysis of additives in oil-based lubricants deposited on a surface without extraction of the sample from the surface presents a challenge. The potential of desorption electrospray ionization mass spectrometry (DESI-MS) for the quantitative surface analysis of an oil additive in a complex oil lubricant matrix without sample extraction has been evaluated. METHODS The quantitative surface analysis of the antioxidant additive octyl (4-hydroxy-3,5-di-tert-butylphenyl)propionate in an oil lubricant matrix was carried out by DESI-MS in the presence of 2-(pentyloxy)ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate as an internal standard. A quadrupole/time-of-flight mass spectrometer fitted with an in-house modified ion source enabling non-proximal DESI-MS was used for the analyses. RESULTS An eight-point calibration curve ranging from 1 to 80 µg/spot of octyl (4-hydroxy-3,5-di-tert-butylphenyl)propionate in an oil lubricant matrix and in the presence of the internal standard was used to determine the quantitative response of the DESI-MS method. The sensitivity and repeatability of the technique were assessed by conducting replicate analyses at each concentration. The limit of detection was determined to be 11 ng/mm2 additive on spot with relative standard deviations in the range 3–14%. CONCLUSIONS The application of DESI-MS to the direct, quantitative surface analysis of a commercial lubricant additive in a native oil lubricant matrix is demonstrated. © 2013 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons, Ltd. PMID:24097398

Ferreting Out the Identity of Gasoline Additives

EPA Science Inventory

Chemical dispersing agents for oil spills, hydraulic fracturing fluids for natural-gas production, and chemicals serving as gasoline additives share a common characteristic—for the most part, they are proprietary compounds. In the name of competitive advantage, companies carefull...

RNA-sequencing-based transcriptome and biochemical analyses of steroidal saponin pathway in a complete set of Allium fistulosum—A. cepa monosomic addition lines

PubMed Central

Abdelrahman, Mostafa; El-Sayed, Magdi; Sato, Shusei; Hirakawa, Hideki; Ito, Shin-ichi; Tanaka, Keisuke; Mine, Yoko; Sugiyama, Nobuo; Suzuki, Minoru; Yamauchi, Naoki

2017-01-01

The genus Allium is a rich source of steroidal saponins, and its medicinal properties have been attributed to these bioactive compounds. The saponin compounds with diverse structures play a pivotal role in Allium’s defense mechanism. Despite numerous studies on the occurrence and chemical structure of steroidal saponins, their biosynthetic pathway in Allium species is poorly understood. The monosomic addition lines (MALs) of the Japanese bunching onion (A. fistulosum, FF) with an extra chromosome from the shallot (A. cepa Aggregatum group, AA) are powerful genetic resources that enable us to understand many physiological traits of Allium. In the present study, we were able to isolate and identify Alliospiroside A saponin compound in A. fistulosum with extra chromosome 2A from shallot (FF2A) and its role in the defense mechanism against Fusarium pathogens. Furthermore, to gain molecular insight into the Allium saponin biosynthesis pathway, high-throughput RNA-Seq of the root, bulb, and leaf of AA, MALs, and FF was carried out using Illumina's HiSeq 2500 platform. An open access Allium Transcript Database (Allium TDB, http://alliumtdb.kazusa.or.jp) was generated based on RNA-Seq data. The resulting assembled transcripts were functionally annotated, revealing 50 unigenes involved in saponin biosynthesis. Differential gene expression (DGE) analyses of AA and MALs as compared with FF (as a control) revealed a strong up-regulation of the saponin downstream pathway, including cytochrome P450, glycosyltransferase, and beta-glucosidase in chromosome 2A. An understanding of the saponin compounds and biosynthesis-related genes would facilitate the development of plants with unique saponin content and, subsequently, improved disease resistance. PMID:28800607

RNA-sequencing-based transcriptome and biochemical analyses of steroidal saponin pathway in a complete set of Allium fistulosum-A. cepa monosomic addition lines.

PubMed

Abdelrahman, Mostafa; El-Sayed, Magdi; Sato, Shusei; Hirakawa, Hideki; Ito, Shin-Ichi; Tanaka, Keisuke; Mine, Yoko; Sugiyama, Nobuo; Suzuki, Yutaka; Yamauchi, Naoki; Shigyo, Masayoshi

2017-01-01

The genus Allium is a rich source of steroidal saponins, and its medicinal properties have been attributed to these bioactive compounds. The saponin compounds with diverse structures play a pivotal role in Allium's defense mechanism. Despite numerous studies on the occurrence and chemical structure of steroidal saponins, their biosynthetic pathway in Allium species is poorly understood. The monosomic addition lines (MALs) of the Japanese bunching onion (A. fistulosum, FF) with an extra chromosome from the shallot (A. cepa Aggregatum group, AA) are powerful genetic resources that enable us to understand many physiological traits of Allium. In the present study, we were able to isolate and identify Alliospiroside A saponin compound in A. fistulosum with extra chromosome 2A from shallot (FF2A) and its role in the defense mechanism against Fusarium pathogens. Furthermore, to gain molecular insight into the Allium saponin biosynthesis pathway, high-throughput RNA-Seq of the root, bulb, and leaf of AA, MALs, and FF was carried out using Illumina's HiSeq 2500 platform. An open access Allium Transcript Database (Allium TDB, http://alliumtdb.kazusa.or.jp) was generated based on RNA-Seq data. The resulting assembled transcripts were functionally annotated, revealing 50 unigenes involved in saponin biosynthesis. Differential gene expression (DGE) analyses of AA and MALs as compared with FF (as a control) revealed a strong up-regulation of the saponin downstream pathway, including cytochrome P450, glycosyltransferase, and beta-glucosidase in chromosome 2A. An understanding of the saponin compounds and biosynthesis-related genes would facilitate the development of plants with unique saponin content and, subsequently, improved disease resistance.

Chemical facility vulnerability assessment project.

PubMed

Jaeger, Calvin D

2003-11-14

Sandia National Laboratories, under the direction of the Office of Science and Technology, National Institute of Justice, conducted the chemical facility vulnerability assessment (CFVA) project. The primary objective of this project was to develop, test and validate a vulnerability assessment methodology (VAM) for determining the security of chemical facilities against terrorist or criminal attacks (VAM-CF). The project also included a report to the Department of Justice for Congress that in addition to describing the VAM-CF also addressed general observations related to security practices, threats and risks at chemical facilities and chemical transport. In the development of the VAM-CF Sandia leveraged the experience gained from the use and development of VAs in other areas and the input from the chemical industry and Federal agencies. The VAM-CF is a systematic, risk-based approach where risk is a function of the severity of consequences of an undesired event, the attack potential, and the likelihood of adversary success in causing the undesired event. For the purpose of the VAM-CF analyses Risk is a function of S, L(A), and L(AS), where S is the severity of consequence of an event, L(A) is the attack potential and L(AS) likelihood of adversary success in causing a catastrophic event. The VAM-CF consists of 13 basic steps. It involves an initial screening step, which helps to identify and prioritize facilities for further analysis. This step is similar to the prioritization approach developed by the American Chemistry Council (ACC). Other steps help to determine the components of the risk equation and ultimately the risk. The VAM-CF process involves identifying the hazardous chemicals and processes at a chemical facility. It helps chemical facilities to focus their attention on the most critical areas. The VAM-CF is not a quantitative analysis but, rather, compares relative security risks. If the risks are deemed too high, recommendations are developed for

Assessment of wastewater and recycled water quality: a comparison of lines of evidence from in vitro, in vivo and chemical analyses.

PubMed

Leusch, Frederic D L; Khan, Stuart J; Gagnon, M Monique; Quayle, Pam; Trinh, Trang; Coleman, Heather; Rawson, Christopher; Chapman, Heather F; Blair, Palenque; Nice, Helen; Reitsema, Tarren

2014-03-01

We investigated water quality at an advanced water reclamation plant and three conventional wastewater treatment plants using an "ecotoxicity toolbox" consisting of three complementary analyses (chemical analysis, in vitro bioanalysis and in situ biological monitoring), with a focus on endocrine disruption. The in vitro bioassays were chosen to provide an appropriately wide coverage of biological effects relevant to managed aquifer recharge and environmental discharge of treated wastewater, and included bioassays for bacterial toxicity (Microtox), genotoxicity (umuC), photosynthesis inhibition (Max-I-PAM) and endocrine effects (E-SCREEN and AR-CALUX). Chemical analysis of hormones and pesticides using LCMSMS was performed in parallel to correlate standard analytical methods with the in vitro assessment. For two plants with surface water discharge into open drains, further field work was carried out to examine in situ effects using mosquitofish (Gambusia holbrooki) as a bioindicator species for possible endocrine effects. The results show considerable cytotoxicity, phytotoxicity, estrogenicity and androgenicity in raw sewage, all of which were significantly reduced by conventional wastewater treatment. No biological response was detected to RO water, suggesting that reverse osmosis is a significant barrier to biologically active compounds. Chemical analysis and in situ monitoring revealed trends consistent with the in vitro results: chemical analysis confirmed the removal trends observed by the bioanalytical tools, and in situ sampling did not reveal any evidence of endocrine disruption specifically due to discharge of treated wastewater (although other sources may be present). Biomarkers of exposure (in vitro) and effect (in vivo or in situ) are complementary and together provide information with a high level of ecological relevance. This study illustrates the utility of combining multiple lines of evidence in the assessment of water quality. Copyright �

Influence of nitrogen fertilization on tropical-grass silage assessed by ensiling process monitoring using chemical and microbial community analyses.

PubMed

Namihira, T; Shinzato, N; Akamine, H; Maekawa, H; Matsui, T

2010-06-01

Utilization of silage in livestock farming is expected to increase in developing countries in the tropical and subtropical parts of the world. The aim of this study was to investigate the influence of nitrogen fertilization on the chemical composition of herbage, ensiling process and silage quality, and to contribute to the improvement of tropical-grass silage preparation. Guinea grass grown under two different nitrogen-fertilizer application conditions [1.5 kg N a(-1) (high-N) and 0.5 kg N a(-1) (low-N)] was packed in plastic bags, and its ensiling process was investigated by chemical and microbial-community analyses. Relatively well-preserved silage was obtained from high-N herbage, which accumulated a high nitrate concentration. Denaturing gradient gel electrophoresis analysis revealed that Lactobacillus plantarum dominated throughout the ensiling of high-N herbage and in the early phase of that of low-N herbage. In low-N silages prepared from ammonium sulfate- and urea-fertilized herbage, Lact. plantarum was replaced by clostridia after 40 and 15 days of ensiling, respectively. Nitrate content of herbage is an important factor that influences silage quality, and careful fertilization management can facilitate stable and successful fermentation of tropical-grass silage without any pretreatment. The positive effect of nitrate on the ensiling process of tropical-grass was proved by microbial-community analysis.

Contracting of Samples for Chemical Analyses. What You Should Know about It

DTIC Science & Technology

1990-08-01

Laboratory (AFSC) Human Systems Division Brooks Air Force Base , Texas 78235-5501 o O NOTICES When Government drawings, specifications, or other data...Assurance Efforts 3 Analyses Costs 3 Certifications 4 How To Protect Your Base And The Air Force 4 References 6 Appendix A - IG Writeup Of A Laboratory...their agency certifications showing the period of certitication and for what analyses. HOW TO PROTECT YOUR BASE AND THE AIR FORCE What I am wondering on

Oil mist and vapour concentrations from drilling fluids: inter- and intra-laboratory comparison of chemical analyses.

PubMed

Galea, Karen S; Searl, Alison; Sánchez-Jiménez, Araceli; Woldbæk, Torill; Halgard, Kristin; Thorud, Syvert; Steinsvåg, Kjersti; Krüger, Kirsti; Maccalman, Laura; Cherrie, John W; van Tongeren, Martie

2012-01-01

There are no recognized analytical methods for measuring oil mist and vapours arising from drilling fluids used in offshore petroleum drilling industry. To inform the future development of improved methods of analysis for oil mist and vapours this study assessed the inter- and intra-laboratory variability in oil mist and vapour analysis. In addition, sample losses during transportation and storage were assessed. Replicate samples for oil mist and vapour were collected using the 37-mm Millipore closed cassette and charcoal tube assembly. Sampling was conducted in a simulated shale shaker room, similar to that found offshore for processing drilling fluids. Samples were analysed at two different laboratories, one in Norway and one in the UK. Oil mist samples were analysed using Fourier transform infrared spectroscopy (FTIR), while oil vapour samples were analysed by gas chromatography (GC). The comparison of replicate samples showed substantial within- and between-laboratory variability in reported oil mist concentrations. The variability in oil vapour results was considerably reduced compared to oil mist, provided that a common method of calibration and quantification was adopted. The study also showed that losses can occur during transportation and storage of samples. There is a need to develop a harmonized method for the quantification of oil mist on filter and oil vapour on charcoal supported by a suitable proficiency testing scheme for laboratories involved in the analysis of occupational hygiene samples for the petroleum industry. The uncertainties in oil mist and vapour measurement have substantial implications in relation to compliance with occupational exposure limits and also in the reliability of any exposure-response information reported in epidemiological studies.

Effects of the addition of blood plasma proteins on physico-chemical properties of emulsion-type pork sausage during cold storage.

PubMed

Kim, Sungho; Jin, Sangkeun; Choi, Jungseok

2017-10-01

Most slaughter blood is discarded, resulting in problems related to costs for wastewater disposal and environmental pollution. However, animal blood contains various proteins such as albumin, globulin and globin and can be used as a natural emulsifier, stabiliser and colour additive. Thus, this study was carried out to investigate the effect of blood plasma proteins on the physico-chemical properties of emulsion-type pork sausages stored at 4°C over 5 weeks. The emulsion-type pork sausages with plasma powders had higher pH than the other treatments during week 5, and higher shear force than the control (P < 0.05). The lightness values of the sausages with plasma powders were lower than the other treatments, whereas the redness and yellowness values were similar with those of the others. The sausages with plasma powders (cattle plasma powder and commercial pig plasma powder) had respectively increased texture properties. In the sensory evaluation, all proteins did not have significant impact on sensory of pork sausages. The results confirmed that plasma protein powders can be considered as a binder for the production of excellent meat products compared to other binders. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Conceptual Chemical Process Design for Sustainability.

EPA Science Inventory

This chapter examines the sustainable design of chemical processes, with a focus on conceptual design, hierarchical and short-cut methods, and analyses of process sustainability for alternatives. The chapter describes a methodology for incorporating process sustainability analyse...

Chemical characteristics of beddings for swine: effects of bedding depths and of addition of inoculums in a pilot-scale.

PubMed

Corrêa, E K; Corezzolla, J L; Corrêa, M N; Bianchi, I; Gil-Turnes, C; Lucia, T

2012-11-01

The effect of depths and of addition of inoculums on the chemical content of swine beddings was evaluated. For beddings 0.25m (25D) and 0.50m (50D) deep, three treatments were tested in two repeats with the same beddings: control (no inoculums); T1 (250g of Bacillus cereus var. toyoii at 8.4×10(7)CFU/g); and T2 (250g of a pool of Bacillus sp. at 8.4×10(7)CFU/g) (250g for 25D and 500g for 50D). For 25D, the C:N ratio was lower, but N, K and C contents were greater than for 50D (P<0.05). The inoculums did not benefit any chemical parameter (P>0.05). In the second repeat, beddings presented lower C:N ratio and greater N, P and K contents than in the first repeat (P<0.05). Thus, the compost produced after using 25D twice had greater fertilizer value than that of 50D. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mobile app for chemical detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klunder, Gregory; Cooper, Chadway R.; Satcher, Jr., Joe H.

The present invention incorporates the camera from a mobile device (phone, iPad, etc.) to capture an image from a chemical test kit and process the image to provide chemical information. A simple user interface enables the automatic evaluation of the image, data entry, gps info, and maintain records from previous analyses.

Fracture Toughness, Mechanical Property, And Chemical Characterization Of A Critical Modification To The NASA SLS Solid Booster Internal Material System

NASA Technical Reports Server (NTRS)

Pancoast, Justin; Garrett, William; Moe, Gulia

2015-01-01

A modified propellant-liner-insulation (PLI) bondline in the Space Launch System (SLS) solid rocket booster required characterization for flight certification. The chemical changes to the PLI bondline and the required additional processing have been correlated to mechanical responses of the materials across the bondline. Mechanical properties testing and analyses included fracture toughness, tensile, and shear tests. Chemical properties testing and analyses included Fourier transform infrared (FTIR) spectroscopy, cross-link density, high-performance liquid chromatography (HPLC), gas chromatography (GC), gel permeation chromatography (GPC), and wave dispersion X-ray fluorescence (WDXRF). The testing identified the presence of the expected new materials and found the functional bondline performance of the new PLI system was not significantly changed from the old system.

Chemical evaluation of electronic cigarettes

PubMed Central

Cheng, Tianrong

2014-01-01

Objective To review the available evidence evaluating the chemicals in refill solutions, cartridges, aerosols and environmental emissions of electronic cigarettes (e-cigarettes). Methods Systematic literature searches were conducted to identify research related to e-cigarettes and chemistry using 5 reference databases and 11 search terms. The search date range was January 2007 to September 2013. The search yielded 36 articles, of which 29 were deemed relevant for analysis. Results The levels of nicotine, tobacco-specific nitrosamines (TSNAs), aldehydes, metals, volatile organic compounds (VOCs), flavours, solvent carriers and tobacco alkaloids in e-cigarette refill solutions, cartridges, aerosols and environmental emissions vary considerably. The delivery of nicotine and the release of TSNAs, aldehydes and metals are not consistent across products. Furthermore, the nicotine level listed on the labels of e-cigarette cartridges and refill solutions is often significantly different from measured values. Phenolic compounds, polycyclic aromatic hydrocarbons and drugs have also been reported in e-cigarette refill solutions, cartridges and aerosols. Varying results in particle size distributions of particular matter emissions from e-cigarettes across studies have been observed. Methods applied for the generation and chemical analyses of aerosols differ across studies. Performance characteristics of e-cigarette devices also vary across and within brands. Conclusions Additional studies based on knowledge of e-cigarette user behaviours and scientifically validated aerosol generation and chemical analysis methods would be helpful in generating reliable measures of chemical quantities. This would allow comparisons of e-cigarette aerosol and traditional smoke constituent levels and would inform an evaluation of the toxicity potential of e-cigarettes. PMID:24732157

Chemical evaluation of electronic cigarettes.

PubMed

Cheng, Tianrong

2014-05-01

To review the available evidence evaluating the chemicals in refill solutions, cartridges, aerosols and environmental emissions of electronic cigarettes (e-cigarettes). Systematic literature searches were conducted to identify research related to e-cigarettes and chemistry using 5 reference databases and 11 search terms. The search date range was January 2007 to September 2013. The search yielded 36 articles, of which 29 were deemed relevant for analysis. The levels of nicotine, tobacco-specific nitrosamines (TSNAs), aldehydes, metals, volatile organic compounds (VOCs), flavours, solvent carriers and tobacco alkaloids in e-cigarette refill solutions, cartridges, aerosols and environmental emissions vary considerably. The delivery of nicotine and the release of TSNAs, aldehydes and metals are not consistent across products. Furthermore, the nicotine level listed on the labels of e-cigarette cartridges and refill solutions is often significantly different from measured values. Phenolic compounds, polycyclic aromatic hydrocarbons and drugs have also been reported in e-cigarette refill solutions, cartridges and aerosols. Varying results in particle size distributions of particular matter emissions from e-cigarettes across studies have been observed. Methods applied for the generation and chemical analyses of aerosols differ across studies. Performance characteristics of e-cigarette devices also vary across and within brands. Additional studies based on knowledge of e-cigarette user behaviours and scientifically validated aerosol generation and chemical analysis methods would be helpful in generating reliable measures of chemical quantities. This would allow comparisons of e-cigarette aerosol and traditional smoke constituent levels and would inform an evaluation of the toxicity potential of e-cigarettes.

A combined approach to investigate the toxicity of an industrial landfill's leachate: Chemical analyses, risk assessment and in vitro assays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baderna, D., E-mail: diego.baderna@marionegri.it; Maggioni, S.; Boriani, E.

2011-05-15

Solid wastes constitute an important and emerging problem. Landfills are still one of the most common ways to manage waste disposal. The risk assessment of pollutants from landfills is becoming a major environmental issue in Europe, due to the large number of sites and to the importance of groundwater protection. Furthermore, there is lack of knowledge for the environmental, ecotoxicological and toxicological characteristics of most contaminants contained into landfill leacheates. Understanding leachate composition and creating an integrated strategy for risk assessment are currently needed to correctly face the landfill issues and to make projections on the long-term impacts of amore » landfill, with particular attention to the estimation of possible adverse effects on human health and ecosystem. In the present study, we propose an integrated strategy to evaluate the toxicity of the leachate using chemical analyses, risk assessment guidelines and in vitro assays using the hepatoma HepG2 cells as a model. The approach was applied on a real case study: an industrial waste landfill in northern Italy for which data on the presence of leachate contaminants are available from the last 11 years. Results from our ecological risk models suggest important toxic effects on freshwater fish and small rodents, mainly due to ammonia and inorganic constituents. Our results from in vitro data show an inhibition of cell proliferation by leachate at low doses and cytotoxic effect at high doses after 48 h of exposure. - Research highlights: {yields} We study the toxicity of leachate from a non-hazardous industrial waste landfill. {yields} We perform chemical analyses, risk assessments and in vitro assays on HepG2 cells. {yields} Risk models suggest toxic effects due to ammonia and inorganic constituents. {yields} In vitro assays show that leachate inhibits cell proliferation at low doses. {yields} Leachate can induce cytotoxic effects on HepG2 cells at high doses.« less

Additive manufacturing of microfluidic glass chips

NASA Astrophysics Data System (ADS)

Kotz, F.; Helmer, D.; Rapp, B. E.

2018-02-01

Additive manufacturing has gained great interest in the microfluidic community due to the numerous channel designs which can be tested in the early phases of a lab-on-a-chip device development. High resolution additive manufacturing like microstereolithography is largely associated with polymers. Polymers are at a disadvantage compared to other materials due to their softness and low chemical resistance. Whenever high chemical and thermal resistance combined with high optical transparency is needed, glasses become the material of choice. However, glasses are difficult to structure at the microscale requiring hazardous chemicals for etching processes. In this work we present additive manufacturing and high resolution patterning of microfluidic chips in transparent fused silica glass using stereolithography and microlithography. We print an amorphous silica nanocomposite at room temperature using benchtop stereolithography printers and a custom built microlithography system based on a digital mirror device. Using microlithography we printed structures with tens of micron resolution. The printed part is then converted to a transparent fused silica glass using thermal debinding and sintering. Printing of a microfluidic chip can be done within 30 minutes. The heat treatment can be done within two days.

Guidelines for the identification of unknown samples for laboratories performing forensic analyses for chemical terrorism.

PubMed

Magnuson, Matthew L; Satzger, R Duane; Alcaraz, Armando; Brewer, Jason; Fetterolf, Dean; Harper, Martin; Hrynchuk, Ronald; McNally, Mary F; Montgomery, Madeline; Nottingham, Eric; Peterson, James; Rickenbach, Michael; Seidel, Jimmy L; Wolnik, Karen

2012-05-01

Since the early 1990s, the FBI Laboratory has sponsored Scientific Working Groups to improve discipline practices and build consensus among the forensic community. The Scientific Working Group on the Forensic Analysis of Chemical, Biological, Radiological and Nuclear Terrorism developed guidance, contained in this document, on issues forensic laboratories encounter when accepting and analyzing unknown samples associated with chemical terrorism, including laboratory capabilities and analytical testing plans. In the context of forensic analysis of chemical terrorism, this guidance defines an unknown sample and addresses what constitutes definitive and tentative identification. Laboratory safety, reporting issues, and postreporting considerations are also discussed. Utilization of these guidelines, as part of planning for forensic analysis related to a chemical terrorism incident, may help avoid unfortunate consequences not only to the public but also to the laboratory personnel. 2011 American Academy of Forensic Sciences. Published 2011. This article is a U.S. Government work and is in the public domain in the U.S.A.

Identifying novel genes and chemicals related to nasopharyngeal cancer in a heterogeneous network.

PubMed

Li, Zhandong; An, Lifeng; Li, Hao; Wang, ShaoPeng; Zhou, You; Yuan, Fei; Li, Lin

2016-05-05

Nasopharyngeal cancer or nasopharyngeal carcinoma (NPC) is the most common cancer originating in the nasopharynx. The factors that induce nasopharyngeal cancer are still not clear. Additional information about the chemicals or genes related to nasopharyngeal cancer will promote a better understanding of the pathogenesis of this cancer and the factors that induce it. Thus, a computational method NPC-RGCP was proposed in this study to identify the possible relevant chemicals and genes based on the presently known chemicals and genes related to nasopharyngeal cancer. To extensively utilize the functional associations between proteins and chemicals, a heterogeneous network was constructed based on interactions of proteins and chemicals. The NPC-RGCP included two stages: the searching stage and the screening stage. The former stage is for finding new possible genes and chemicals in the heterogeneous network, while the latter stage is for screening and removing false discoveries and selecting the core genes and chemicals. As a result, five putative genes, CXCR3, IRF1, CDK1, GSTP1, and CDH2, and seven putative chemicals, iron, propionic acid, dimethyl sulfoxide, isopropanol, erythrose 4-phosphate, β-D-Fructose 6-phosphate, and flavin adenine dinucleotide, were identified by NPC-RGCP. Extensive analyses provided confirmation that the putative genes and chemicals have significant associations with nasopharyngeal cancer.

Identifying novel genes and chemicals related to nasopharyngeal cancer in a heterogeneous network

PubMed Central

Li, Zhandong; An, Lifeng; Li, Hao; Wang, ShaoPeng; Zhou, You; Yuan, Fei; Li, Lin

2016-01-01

Nasopharyngeal cancer or nasopharyngeal carcinoma (NPC) is the most common cancer originating in the nasopharynx. The factors that induce nasopharyngeal cancer are still not clear. Additional information about the chemicals or genes related to nasopharyngeal cancer will promote a better understanding of the pathogenesis of this cancer and the factors that induce it. Thus, a computational method NPC-RGCP was proposed in this study to identify the possible relevant chemicals and genes based on the presently known chemicals and genes related to nasopharyngeal cancer. To extensively utilize the functional associations between proteins and chemicals, a heterogeneous network was constructed based on interactions of proteins and chemicals. The NPC-RGCP included two stages: the searching stage and the screening stage. The former stage is for finding new possible genes and chemicals in the heterogeneous network, while the latter stage is for screening and removing false discoveries and selecting the core genes and chemicals. As a result, five putative genes, CXCR3, IRF1, CDK1, GSTP1, and CDH2, and seven putative chemicals, iron, propionic acid, dimethyl sulfoxide, isopropanol, erythrose 4-phosphate, β-D-Fructose 6-phosphate, and flavin adenine dinucleotide, were identified by NPC-RGCP. Extensive analyses provided confirmation that the putative genes and chemicals have significant associations with nasopharyngeal cancer. PMID:27149165

Chemical and Isotopic Exploration: A Tale of Two Telepresence-Enabled Cruises

NASA Astrophysics Data System (ADS)

Wankel, S. D.; Michel, A.

2016-02-01

Ocean exploration has traditionally required a large team of shipboard scientists for quick decision-making as well as for sample handling and processing tasks. However, with the development of new field-going in situ sensors for chemical oceanography, comes the capability of making measurements in the deep ocean without the need for sample collection, processing and laboratory analysis. Through our participation in two cruises aboard the E/V Nautilus, we tested a new model for ocean exploration using Telepresence technology for making chemical analyses in the deep ocean with a laser spectrometer designed for in situ analyses of methane and carbon dioxide. In 2014, we used the E/V Nautilus and ROV Hercules to explore the chemical and isotopic composition of fluids and bubbles in the crater of the Kick `Em Jenny volcano ( 180m depth) just northwest off the island of Grenada. In 2015, we carried out exploration of a mud volcano/brine pool in the western Gulf of Mexico ( 1300m depth). For our focused chemical explorations in 2014, one scientist was shipboard while two were ashore at the Inner Space Center at the University of Rhode Island. Decisions concerning instrument parameters, sampling strategies and data collection and management were all carried out through this two-way remote operation scheme, while the shipboard scientist was responsible for all deployments, maintenance, and troubleshooting technical issues with instrumentation. In comparison, in 2015, two scientists were shipboard. Here we compare the successes and challenges of using Telepresence for chemical exploration. In addition, we detail our interactions with scientists, educators, and interested citizens ashore. The use of Telepresence enhanced both science communication, by enabling direct scientist-to-scientist interactions and decision-making, and science education, through broad participation of a global audience. As in situ chemical sensing advances, telepresence promises to increase

USING DOSE ADDITION TO ESTIMATE CUMULATIVE RISKS FROM EXPOSURES TO MULTIPLE CHEMICALS

EPA Science Inventory

The Food Quality Protection Act (FQPA) of 1996 requires the EPA to consider the cumulative risk from exposure to multiple chemicals that have a common mechanism of toxicity. Three methods, hazard index (HI), point-of-departure index (PODI), and toxicity equivalence factor (TEF), ...

Maps showing mines, quarries, and prospects, with analyses of samples, Gee Creek Wilderness, Polk and Monroe counties, Tennessee

USGS Publications Warehouse

Gazdik, Gertrude C.; Behum, Paul T.

1983-01-01

During the recent U.S. Bureau of Mines field investigation, 21 samples were collected (fig. 2) and were submitted to the Bureau's Reno Metallurgy Research Center, Reno, Nev., for analysis. All samples were tested for 40 elements by semiquantitative spectrographic analyses. Additional testing by atomic absorption, neutron activation, and wet chemical techniques was performed for selected elements on some samples. Two shale samples were submitted to the Bureau of Mines, Tuscaloosa Metallurgy Research Center, Tuscaloosa, Ala., for the evaluation of ceramic properties. 

Giant increase in piezoelectric coefficient of AlN by Mg-Nb simultaneous addition and multiple chemical states of Nb

NASA Astrophysics Data System (ADS)

Uehara, Masato; Shigemoto, Hokuto; Fujio, Yuki; Nagase, Toshimi; Aida, Yasuhiro; Umeda, Keiichi; Akiyama, Morito

2017-09-01

Aluminum nitride (AlN) is one of piezoelectric materials, which are eagerly anticipated for use in microelectromechanical systems (MEMS) applications such as communication resonators, sensors, and energy harvesters. AlN is particularly excellent in generated voltage characteristics for the MEMS rather than oxide piezoelectric materials such as lead zirconium titanate Pb(Zr, Ti)O3. However, it is necessary to improve the piezoelectric properties of AlN in order to advance the performance of the MEMS. We dramatically increased the piezoelectric coefficient d33 of AlN films by simultaneously adding magnesium (Mg) and niobium (Nb). The d33 of Mg39.3Nb25.0Al35.7N is 22 pC/N, which is about four times that of AlN. The d33 is increased by Mg and Nb simultaneous addition, and is not increased by Mg or Nb single addition. Interestingly, the Nb has multiple chemical states, and which are influenced by the Mg concentration.

Studies on nano-additive for the substitution of hazardous chemical substances in antifouling coatings for the protection of ship hulls.

PubMed

Zhao, Xiaodong; Fan, Weijie; Duan, Jizhou; Hou, Baorong

2014-07-01

Adhesion and growth of biofouling organisms have severe influence on the reliability, service life and environmental adaptability of marine ships. Based on the bactericidal capacity of cuprous oxide and photochemical effect of nano-additive, environment-friendly and efficient marine antifouling paints were prepared in this study. The evaluation of the antifouling paints was carried out by the laboratory method using bacteria and phytoplanktonic microorganisms as target organisms, as well as measurements with panels in shallow submergence in natural seawater. Results showed good agreement of all the tests, indicating the remarkable antifouling performance of the paints. To our knowledge, this was one of the first systematic studies on effects of nano-additive for the substitution of hazardous chemical substances in antifouling coatings for the protection of ship hulls by measurements on bacterial inhibition, algal adhesion and growth of large organisms.

Assessing electronic cigarette emissions: linking physico-chemical properties to product brand, e-liquid flavoring additives, operational voltage and user puffing patterns.

PubMed

Zhao, Jiayuan; Nelson, Jordan; Dada, Oluwabunmi; Pyrgiotakis, Georgios; Kavouras, Ilias G; Demokritou, Philip

2018-02-01

Users of electronic cigarettes (e-cigs) are exposed to particles and other gaseous pollutants. However, major knowledge gaps on the physico-chemical properties of such exposures and contradictory data in published literature prohibit health risk assessment. Here, the effects of product brand, type, e-liquid flavoring additives, operational voltage, and user puffing patterns on emissions were systematically assessed using a recently developed, versatile, e-cig exposure generation platform and state-of-the-art analytical methods. Parameters of interest in this systematic evaluation included two brands (A and B), three flavors (tobacco, menthol, and fruit), three types of e-cigs (disposable, pre-filled, and refillable tanks), two puffing protocols (4 and 2 s/puff), and four operational voltages (2.2-5.7 V). Particles were generated at a high number concentration (10 6 -10 7 particles/cm 3 ). The particle size distribution was bi-modal (∼200 nm and 1 µm). Furthermore, organic species (humectants propylene glycol and glycerin, nicotine) that were present in e-liquid and trace metals (potassium and sodium) that were present on e-cig heating coil were also released into the emission. In addition, combustion-related byproducts, such as benzene and toluene, were also detected in the range of 100-38,000 ppbv/puff. Parametric analyzes performed in this study show the importance of e-cig brand, type, flavor additives, user puffing pattern (duration and frequency), and voltage on physico-chemical properties of emissions. This observed influence is indicative of the complexity associated with the toxicological screening of emissions from e-cigs and needs to be taken into consideration.

An Assessment of the Model of Concentration Addition for Predicting the Estrogenic Activity of Chemical Mixtures in Wastewater Treatment Works Effluents

PubMed Central

Thorpe, Karen L.; Gross-Sorokin, Melanie; Johnson, Ian; Brighty, Geoff; Tyler, Charles R.

2006-01-01

The effects of simple mixtures of chemicals, with similar mechanisms of action, can be predicted using the concentration addition model (CA). The ability of this model to predict the estrogenic effects of more complex mixtures such as effluent discharges, however, has yet to be established. Effluents from 43 U.K. wastewater treatment works were analyzed for the presence of the principal estrogenic chemical contaminants, estradiol, estrone, ethinylestradiol, and nonylphenol. The measured concentrations were used to predict the estrogenic activity of each effluent, employing the model of CA, based on the relative potencies of the individual chemicals in an in vitro recombinant yeast estrogen screen (rYES) and a short-term (14-day) in vivo rainbow trout vitellogenin induction assay. Based on the measured concentrations of the four chemicals in the effluents and their relative potencies in each assay, the calculated in vitro and in vivo responses compared well and ranged between 3.5 and 87 ng/L of estradiol equivalents (E2 EQ) for the different effluents. In the rYES, however, the measured E2 EQ concentrations in the effluents ranged between 0.65 and 43 ng E2 EQ/L, and they varied against those predicted by the CA model. Deviations in the estimation of the estrogenic potency of the effluents by the CA model, compared with the measured responses in the rYES, are likely to have resulted from inaccuracies associated with the measurement of the chemicals in the extracts derived from the complex effluents. Such deviations could also result as a consequence of interactions between chemicals present in the extracts that disrupted the activation of the estrogen response elements in the rYES. E2 EQ concentrations derived from the vitellogenic response in fathead minnows exposed to a series of effluent dilutions were highly comparable with the E2 EQ concentrations derived from assessments of the estrogenic potency of these dilutions in the rYES. Together these data support the

Portable gas chromatograph mass spectrometer for on-site chemical analyses

DOEpatents

Haas, Jeffrey S.; Bushman, John F.; Howard, Douglas E.; Wong, James L.; Eckels, Joel D.

2002-01-01

A portable, lightweight (approximately 25 kg) gas chromatograph mass spectrometer, including the entire vacuum system, can perform qualitative and quantitative analyses of all sample types in the field. The GC/MS has a conveniently configured layout of components for ease of serviceability and maintenance. The GC/MS system can be transported under operating or near-operating conditions (i.e., under vacuum and at elevated temperature) to reduce the downtime before samples can be analyzed on-site.

Teachers' Misconceptions about the Effects of Addition of More Reactants or Products on Chemical Equilibrium

ERIC Educational Resources Information Center

Cheung, Derek; Ma, Hong-jia; Yang, Jie

2009-01-01

The importance of research on misconceptions about chemical equilibrium is well recognized by educators, but in the past, researchers' interest has centered on student misconceptions and has neglected teacher misconceptions. Focusing on the effects of adding more reactants or products on chemical equilibrium, this article discusses the various…

COCAP: a carbon dioxide analyser for small unmanned aircraft systems

NASA Astrophysics Data System (ADS)

Kunz, Martin; Lavric, Jost V.; Gerbig, Christoph; Tans, Pieter; Neff, Don; Hummelgård, Christine; Martin, Hans; Rödjegård, Henrik; Wrenger, Burkhard; Heimann, Martin

2018-03-01

Unmanned aircraft systems (UASs) could provide a cost-effective way to close gaps in the observation of the carbon cycle, provided that small yet accurate analysers are available. We have developed a COmpact Carbon dioxide analyser for Airborne Platforms (COCAP). The accuracy of COCAP's carbon dioxide (CO2) measurements is ensured by calibration in an environmental chamber, regular calibration in the field and by chemical drying of sampled air. In addition, the package contains a lightweight thermal stabilisation system that reduces the influence of ambient temperature changes on the CO2 sensor by 2 orders of magnitude. During validation of COCAP's CO2 measurements in simulated and real flights we found a measurement error of 1.2 µmol mol-1 or better with no indication of bias. COCAP is a self-contained package that has proven well suited for the operation on board small UASs. Besides carbon dioxide dry air mole fraction it also measures air temperature, humidity and pressure. We describe the measurement system and our calibration strategy in detail to support others in tapping the potential of UASs for atmospheric trace gas measurements.

Multi-Platform Metabolomic Analyses of Rat Urine Following Exposure to Perfluorinated Chemicals (PFCs)

EPA Science Inventory

Perfluorinated chemicals (PFCs), namely perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), represent an emerging class of persistent and bioaccumulative compounds. Global occurrence of these fluorochemicals, coupled with probable human exposure, has prompted inv...

The dilemma in prioritizing chemicals for environmental analysis: known versus unknown hazards.

PubMed

Anna, Sobek; Sofia, Bejgarn; Christina, Rudén; Magnus, Breitholtz

2016-08-10

A major challenge for society is to manage the risks posed by the many chemicals continuously emitted to the environment. All chemicals in production and use cannot be monitored and science-based strategies for prioritization are essential. In this study we review available data to investigate which substances are included in environmental monitoring programs and published research studies reporting analyses of chemicals in Baltic Sea fish between 2000 and 2012. Our aim is to contribute to the discussion of priority settings in environmental chemical monitoring and research, which is closely linked to chemical management. In total, 105 different substances or substance groups were analyzed in Baltic Sea fish. Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were the most studied substances or substance groups. The majority, 87%, of all analyses comprised 20% of the substances or substance groups, whereas 46 substance groups (44%) were analyzed only once. Almost three quarters of all analyses regarded a POP-substance (persistent organic pollutant). These results demonstrate that the majority of analyses on environmental contaminants in Baltic Sea fish concern a small number of already regulated chemicals. Legacy pollutants such as POPs pose a high risk to the Baltic Sea due to their hazardous properties. Yet, there may be a risk that prioritizations for chemical analyses are biased based on the knowns of the past. Such biases may lead to society failing in identifying risks posed by yet unknown hazardous chemicals. Alternative and complementary ways to identify priority chemicals are needed. More transparent communication between risk assessments performed as part of the risk assessment process within REACH and monitoring programs, and information on chemicals contained in consumer articles, would offer ways to identify chemicals for environmental analysis.

Conceptual Chemical Process Design for Sustainability. ...

EPA Pesticide Factsheets

This chapter examines the sustainable design of chemical processes, with a focus on conceptual design, hierarchical and short-cut methods, and analyses of process sustainability for alternatives. The chapter describes a methodology for incorporating process sustainability analyses throughout the conceptual design. Hierarchical and short-cut decision-making methods will be used to approach sustainability. An example showing a sustainability-based evaluation of chlor-alkali production processes is presented with economic analysis and five pollutants described as emissions. These emissions are analyzed according to their human toxicity potential by ingestion using the Waste Reduction Algorithm and a method based on US Environmental Protection Agency reference doses, with the addition of biodegradation for suitable components. Among the emissions, mercury as an element will not biodegrade, and results show the importance of this pollutant to the potential toxicity results and therefore the sustainability of the process design. The dominance of mercury in determining the long-term toxicity results when energy use is included suggests that all process system evaluations should (re)consider the role of mercury and other non-/slow-degrading pollutants in sustainability analyses. The cycling of nondegrading pollutants through the biosphere suggests the need for a complete analysis based on the economic, environmental, and social aspects of sustainability. Chapter reviews

Chemical and optical characterization of white efflorescences on dry fermented sausages under modified atmosphere packaging.

PubMed

Walz, Felix H; Gibis, Monika; Herrmann, Kurt; Hinrichs, Jörg; Weiss, Jochen

2017-11-01

Dry fermented sausages that are packed under modified atmosphere are often affected by the formation of white crystals on the surface. These so called efflorescences are rejected by consumers and lead to high financial losses for the meat processing industry. In this study, the distribution of efflorescence-causing components was investigated over the sausage profile during 8 weeks of storage under modified atmosphere at 4 °C. In addition, two visual methods (image and sensory analyses) were compared regarding the ability to quantify the efflorescence content. The initial formation of efflorescences was observed after 2 weeks (7%). After 4 weeks of storage, 23.4% of the sausage surface was covered with efflorescences, and the amount of efflorescences did not change significantly by the end of storage. Furthermore, chemical analyses revealed that magnesium (increased by 98.1%), lactate (increased by 54.2%) and creatine (increased by 51.8%) are enriched on the sausage surface during storage. Sensory and image analyses lead to comparable results (r = 0.992) and therefore both are suitable to quantify the amount of efflorescences. The moisture gradient in the interior of the sausages which is built upon drying is supposed to be the driving force for the movement of efflorescence-causing compounds. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Toxic Release Inventory Chemicals by Groupings

EPA Pesticide Factsheets

The Toxics Release Inventory (TRI) makes available information for more than 600 toxic chemicals that are being used, manufactured, treated, transported, or released into the environment since 1987. EPA makes changes (additions, deletions, or changes in definition) to the TRI chemical list. As a result, the TRI list of reportable toxic chemicals can vary from year to year. EPA created groupings such as the core chemical lists (of 1988, 1991, 1995, 1998, 2000, and 2001) to facilitate year-to-year comparison based on a consistent set of reporting requirements and assure that changes in TRI release or other waste management amounts do not reflect the addition, deletion, or change in definition of reportable chemicals. EPA also created groupings of specific chemicals of interest by categories such as Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), Hazardous Air Pollutants (HAPs), Metals, Newly Added TRI Chemicals in 1995, Occupational Safety and Health Administration (OSHA, Carcinogens), Persistent Bioaccumulative and Toxic (PBT) Chemicals, and Priority Chemicals.

Chemical and isotopic database of water and gas from hydrothermal systems with an emphasis for the western United States

USGS Publications Warehouse

Mariner, R.H.; Venezky, D.Y.; Hurwitz, S.

2006-01-01

Chemical and isotope data accumulated by two USGS Projects (led by I. Barnes and R. Mariner) over a time period of about 40 years can now be found using a basic web search or through an image search (left). The data are primarily chemical and isotopic analyses of waters (thermal, mineral, or fresh) and associated gas (free and/or dissolved) collected from hot springs, mineral springs, cold springs, geothermal wells, fumaroles, and gas seeps. Additional information is available about the collection methods and analysis procedures.The chemical and isotope data are stored in a MySQL database and accessed using PHP from a basic search form below. Data can also be accessed using an Open Source GIS called WorldKit by clicking on the image to the left. Additional information is available about WorldKit including the files used to set up the site.

Assessing the Extent of Sediment Contamination Around Creosote-treated Pilings Through Chemical and Biological Analyses

NASA Astrophysics Data System (ADS)

Stefansson, E. S.

2008-12-01

Creosote is a common wood preservative used to treat marine structures, such as docks and bulkheads. Treated dock pilings continually leach polycyclic aromatic hydrocarbons (PAHs) and other creosote compounds into the surrounding water and sediment. Over time, these compounds can accumulate in marine sediments, reaching much greater concentrations than those in seawater. The purpose of this study was to assess the extent of creosote contamination in sediments, at a series of distances from treated pilings. Three pilings were randomly selected from a railroad trestle in Fidalgo Bay, WA and sediment samples were collected at four distances from each: 0 meters, 0.5 meters, 1 meter, and 2 meters. Samples were used to conduct two bioassays: an amphipod bioassay (Rhepoxynius abronius) and a sand dollar embryo bioassay. Grain size and PAH content (using a fluorometric method) were also measured. Five samples in the amphipod bioassay showed significantly lower effective survival than the reference sediment. These consisted of samples closest to the piling at 0 and 0.5 meters. One 0 m sample in the sand dollar embryo bioassay also showed a significantly lower percentage of normal embryos than the reference sediment. Overall, results strongly suggest that creosote-contaminated sediments, particularly those closest to treated pilings, can negatively affect both amphipods and echinoderm embryos. Although chemical data were somewhat ambiguous, 0 m samples had the highest levels of PAHs, which corresponded to the lowest average survival in both bioassays. Relatively high levels of PAHs were found as far as 2 meters away from pilings. Therefore, we cannot say how far chemical contamination can spread from creosote-treated pilings, and at what distance this contamination can still affect marine organisms. These results, as well as future research, are essential to the success of proposed piling removal projects. In addition to creosote-treated pilings, contaminated sediments must

In-Space Chemical Propulsion System Model

NASA Technical Reports Server (NTRS)

Byers, David C.; Woodcock, Gordon; Benfield, Michael P. J.

2004-01-01

Multiple, new technologies for chemical systems are becoming available and include high temperature rockets, very light propellant tanks and structures, new bipropellant and monopropellant options, lower mass propellant control components, and zero boil off subsystems. Such technologies offer promise of increasing the performance of in-space chemical propulsion for energetic space missions. A mass model for pressure-fed, Earth and space-storable, advanced chemical propulsion systems (ACPS) was developed in support of the NASA MSFC In-Space Propulsion Program. Data from flight systems and studies defined baseline system architectures and subsystems and analyses were formulated for parametric scaling relationships for all ACPS subsystem. The paper will first provide summary descriptions of the approaches used for the systems and the subsystems and then present selected analyses to illustrate use of the model for missions with characteristics of current interest.

In-Space Chemical Propulsion System Model

NASA Technical Reports Server (NTRS)

Byers, David C.; Woodcock, Gordon; Benfield, M. P. J.

2004-01-01

Multiple, new technologies for chemical systems are becoming available and include high temperature rockets, very light propellant tanks and structures, new bipropellant and monopropellant options, lower mass propellant control components, and zero boil off subsystems. Such technologies offer promise of increasing the performance of in-space chemical propulsion for energetic space missions. A mass model for pressure-fed, Earth and space-storable, advanced chemical propulsion systems (ACPS) was developed in support of the NASA MSFC In-Space Propulsion Program. Data from flight systems and studies defined baseline system architectures and subsystems and analyses were formulated for parametric scaling relationships for all ACPS subsystems. The paper will first provide summary descriptions of the approaches used for the systems and the subsystems and then present selected analyses to illustrate use of the model for missions with characteristics of current interest.

10 CFR 436.24 - Uncertainty analyses.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Procedures for Life Cycle Cost Analyses § 436.24 Uncertainty analyses. If particular items of cost data or... impact of uncertainty on the calculation of life cycle cost effectiveness or the assignment of rank order... and probabilistic analysis. If additional analysis casts substantial doubt on the life cycle cost...

10 CFR 436.24 - Uncertainty analyses.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Procedures for Life Cycle Cost Analyses § 436.24 Uncertainty analyses. If particular items of cost data or... impact of uncertainty on the calculation of life cycle cost effectiveness or the assignment of rank order... and probabilistic analysis. If additional analysis casts substantial doubt on the life cycle cost...

10 CFR 436.24 - Uncertainty analyses.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Procedures for Life Cycle Cost Analyses § 436.24 Uncertainty analyses. If particular items of cost data or... impact of uncertainty on the calculation of life cycle cost effectiveness or the assignment of rank order... and probabilistic analysis. If additional analysis casts substantial doubt on the life cycle cost...

10 CFR 436.24 - Uncertainty analyses.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Procedures for Life Cycle Cost Analyses § 436.24 Uncertainty analyses. If particular items of cost data or... impact of uncertainty on the calculation of life cycle cost effectiveness or the assignment of rank order... and probabilistic analysis. If additional analysis casts substantial doubt on the life cycle cost...

Mineralogical and chemical characterization of iron-, manganese-, and copper-containing synthetic hydroxyapatites.

PubMed

Sutter, B; Ming, D W; Clearfield, A; Hossner, L R

2003-01-01

The National Aeronautics and Space Administration's (NASA) Advanced Life Support (ALS) Program is evaluating the use of Fe-, Mn-, and Cu-containing synthetic hydroxyapatite (SHA) as a slow release fertilizer for crops that might be grown on the International Space Station or at Lunar and Martian outposts. Separate Fe-, Mn-, and Cu-containing SHA materials along with a transition-metal free SHA (pure-SHA) were synthesized using a precipitation method. Chemical and mineralogical analyses determined if and how Fe, Mn, and Cu were incorporated into the SHA structure. X-ray diffraction (XRD), Rietveld refinement, and transmission electron microscopy (TEM) confirmed that SHA materials with the apatite structure were produced. Chemical analyses indicated that the metal containing SHA materials were deficient in Ca relative to pure-SHA. The shift in the infrared PO4-mu 3 vibrations, smaller unit cell parameters, smaller particle size, and greater structural strain for Fe-, Mn-, and Cu-containing SHA compared with pure-SHA suggested that Fe, Mn, and Cu were incorporated into SHA structure. Rietveld analyses revealed that Fe, Mn, and Cu substituted into the Ca2 site of SHA. An Fe-rich phase was detected by TEM analyses and backscattered electron microscopy in the Fe-containing SHA material with the greatest Fe content. The substitution of metals into SHA suggests that metal-SHA materials are potential slow-release sources of micronutrients for plant uptake in addition to Ca and P.

Mineralogical and chemical characterization of iron-, manganese-, and copper-containing synthetic hydroxyapatites

NASA Technical Reports Server (NTRS)

Sutter, B.; Ming, D. W.; Clearfield, A.; Hossner, L. R.

2003-01-01

The National Aeronautics and Space Administration's (NASA) Advanced Life Support (ALS) Program is evaluating the use of Fe-, Mn-, and Cu-containing synthetic hydroxyapatite (SHA) as a slow release fertilizer for crops that might be grown on the International Space Station or at Lunar and Martian outposts. Separate Fe-, Mn-, and Cu-containing SHA materials along with a transition-metal free SHA (pure-SHA) were synthesized using a precipitation method. Chemical and mineralogical analyses determined if and how Fe, Mn, and Cu were incorporated into the SHA structure. X-ray diffraction (XRD), Rietveld refinement, and transmission electron microscopy (TEM) confirmed that SHA materials with the apatite structure were produced. Chemical analyses indicated that the metal containing SHA materials were deficient in Ca relative to pure-SHA. The shift in the infrared PO4-mu 3 vibrations, smaller unit cell parameters, smaller particle size, and greater structural strain for Fe-, Mn-, and Cu-containing SHA compared with pure-SHA suggested that Fe, Mn, and Cu were incorporated into SHA structure. Rietveld analyses revealed that Fe, Mn, and Cu substituted into the Ca2 site of SHA. An Fe-rich phase was detected by TEM analyses and backscattered electron microscopy in the Fe-containing SHA material with the greatest Fe content. The substitution of metals into SHA suggests that metal-SHA materials are potential slow-release sources of micronutrients for plant uptake in addition to Ca and P.

Results of chemical and isotopic analyses of sediment and water from alluvium of the Canadian River near a closed municipal landfill, Norman, Oklahoma

USGS Publications Warehouse

Breit, George N.; Tuttle, Michele L.W.; Cozzarelli, Isabelle M.; Christenson, Scott C.; Jaeschke, Jeanne B.; Fey, David L.; Berry, Cyrus J.

2005-01-01

Results of physical and chemical analyses of sediment and water collected near a closed municipal landfill at Norman, Oklahoma are presented in this report. Sediment analyses are from 40 samples obtained by freeze-shoe coring at 5 sites, and 14 shallow (depth <1.3 m) sediment samples. The sediment was analyzed to determine grain size, the abundance of extractable iron species and the abundances and isotopic compositions of forms of sulfur. Water samples included pore water from the freeze-shoe core, ground water, and surface water. Pore water from 23 intervals of the core was collected and analyzed for major and trace dissolved species. Thirteen ground-water samples obtained from wells within a few meters of the freeze-shoe core sites and one from the landfill were analyzed for major and trace elements as well as the sulfur and oxygen isotope composition of dissolved sulfate. Samples of surface water were collected at 10 sites along the Canadian River from New Mexico to central Oklahoma. These river-water samples were analyzed for major elements, trace elements, and the isotopic composition of dissolved sulfate.

78 FR 74218 - Imposition of Additional Sanctions on Syria Under the Chemical and Biological Weapons Control and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-10

... Chemical and Biological Weapons Control and Warfare Elimination Act of 1991 AGENCY: Bureau of International... determination was made that the Government of Syria used chemical weapons in violation of international law or lethal chemical weapons against its own nationals. Notice of this determination was published on...

Vector diagram of the chemical compositions of tektites and earth lavas

NASA Technical Reports Server (NTRS)

Kvasha, L. G.; Gorshkov, G. S.

1978-01-01

The chemical compositions of tektites and various volcanic glasses, similar in composition to tektites are compared by a petrochemical method. The advantage of the method is that a large number of chemical analyses of igneous rocks can be graphically compared with the help of vectors, plotted in relation to six parameters. These parameters, calculated from ratios of the main oxides given by silicate analysis, reflect the chief characteristics of igneous rock. Material for the study was suppled by data from chemical analysis characterizing tektites of all known locations and data from chemical analyses of obsidians similar in chemical composition to tektites of various petrographical provinces.

The relationship of physical and chemical conditions of CEP diluent with egg yolk addition to bull spermatozoa quality before and after storage at temperaturof 4-5°C

NASA Astrophysics Data System (ADS)

Ducha, N.; Hariani, D.; Budijastuti, W.

2018-01-01

Storage of semen requires diluent to dilute semen and maintain sperm quality. One of the diluent for bull semen was CEP. The purpose of this study was to assess the association of bull spermatozoa quality with the physical and chemical conditions of CEP diluents with the addition of egg yolk before and after the storage process. The study used Limousin bull with 5 replications. The quality of spermatozoa included motility and viability. Physical and chemical conditions included the pH and osmolarity of the diluent. The motility of spermatozoa was observed under a light microscope with 200 X magnification at 37°C by two people. The viability of spermatozoa was observed under a light microscope with 400 X magnification with nigrosine eosin staining. Data were analyzed with ANOVA and continued Duncan’s test. Dilution pH was measured using pH indicator paper ranging from 6-8. The osmolarity of the diluent was measured by electrical osmolarity. The results showed that the addition of egg yolk in the CEP diluent decreased the pH and increased osmolartitas, but the quality of spermatozoa can be kept up to 8 days of storage. The conclusion in this study was the addition of egg yolk in the CEP diluent provided physical and chemical conditions that can maintain the quality of spermatozoa during storage at a temperature of 4-5 ° C.

Statistical Data Analyses of Trace Chemical, Biochemical, and Physical Analytical Signatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Udey, Ruth Norma

Analytical and bioanalytical chemistry measurement results are most meaningful when interpreted using rigorous statistical treatments of the data. The same data set may provide many dimensions of information depending on the questions asked through the applied statistical methods. Three principal projects illustrated the wealth of information gained through the application of statistical data analyses to diverse problems.

Antimony leaching and chemical species analyses in an industrial solid waste: Surface and bulk speciation using ToF-SIMS and XANES.

PubMed

Kappen, P; Ferrando-Miguel, G; Reichman, S M; Innes, L; Welter, E; Pigram, P J

2017-05-05

The surface chemistry and bulk chemical speciation of solid industrial wastes containing 8wt-% antimony (Sb) were investigated using synchrotron X-ray Absorption Near Edge Structure (XANES) and Time-of-Flight Ion Secondary Mass Spectrometry (ToF-SIMS). Leaching experiments were conducted in order to better understand the behavior of Sb in waste streams and to inform regulatory management of antimony-containing wastes. The experiments also demonstrate how a combination of XANES and ToF-SIMS adds value to the field of waste investigations. Leaching treatments (acid and base) were performed at a synchrotron over 24h time periods. Surface analyses of the wastes before leaching showed the presence of Sb associated with S and O. Bulk analyses revealed Sb to be present, primarily, as trivalent sulfide species. Both acid and base leaching did not change the antimony speciation on the solid. Leaching transferred about 1% of the total Sb into solution where Sb was found to be present as Sb(V). XANES data showed similarities between leachate and FeSbO 4 . During base leaching, the Sb content in solution gradually increased over time, and potential desorption mechanisms are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

15 CFR 713.4 - Advance declaration requirements for additionally planned production, processing, or consumption...

Code of Federal Regulations, 2010 CFR

2010-01-01

... INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE CHEMICAL WEAPONS CONVENTION REGULATIONS ACTIVITIES INVOLVING SCHEDULE 2 CHEMICALS § 713.4 Advance declaration requirements for additionally planned production... additionally planned production, processing, or consumption of Schedule 2 chemicals. 713.4 Section 713.4...

15 CFR 713.4 - Advance declaration requirements for additionally planned production, processing, or consumption...

Code of Federal Regulations, 2011 CFR

2011-01-01

... INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE CHEMICAL WEAPONS CONVENTION REGULATIONS ACTIVITIES INVOLVING SCHEDULE 2 CHEMICALS § 713.4 Advance declaration requirements for additionally planned production... additionally planned production, processing, or consumption of Schedule 2 chemicals. 713.4 Section 713.4...

Detection of uranium and chemical state analysis of individual radioactive microparticles emitted from the Fukushima nuclear accident using multiple synchrotron radiation X-ray analyses.

PubMed

Abe, Yoshinari; Iizawa, Yushin; Terada, Yasuko; Adachi, Kouji; Igarashi, Yasuhito; Nakai, Izumi

2014-09-02

Synchrotron radiation (SR) X-ray microbeam analyses revealed the detailed chemical nature of radioactive aerosol microparticles emitted during the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, resulting in better understanding of what occurred in the plant during the early stages of the accident. Three spherical microparticles (∼2 μm, diameter) containing radioactive Cs were found in aerosol samples collected on March 14th and 15th, 2011, in Tsukuba, 172 km southwest of the FDNPP. SR-μ-X-ray fluorescence analysis detected the following 10 heavy elements in all three particles: Fe, Zn, Rb, Zr, Mo, Sn, Sb, Te, Cs, and Ba. In addition, U was found for the first time in two of the particles, further confirmed by U L-edge X-ray absorption near-edge structure (XANES) spectra, implying that U fuel and its fission products were contained in these particles along with radioactive Cs. These results strongly suggest that the FDNPP was damaged sufficiently to emit U fuel and fission products outside the containment vessel as aerosol particles. SR-μ-XANES spectra of Fe, Zn, Mo, and Sn K-edges for the individual particles revealed that they were present at high oxidation states, i.e., Fe(3+), Zn(2+), Mo(6+), and Sn(4+) in the glass matrix, confirmed by SR-μ-X-ray diffraction analysis. These radioactive materials in a glassy state may remain in the environment longer than those emitted as water-soluble radioactive Cs aerosol particles.

A thermal and chemical degradation approach to decipher pristane and phytane precursors in sedimentary organic matter

USGS Publications Warehouse

Koopmans, M.P.; Rijpstra, W.I.C.; Klapwijk, M.M.; De Leeuw, J. W.; Lewan, M.D.; Sinninghe, Damste J.S.

1999-01-01

A thermal and chemical degradation approach was followed to determine the precursors of pristane (Pr) and phytane (Ph) in samples from the Gessoso-solfifera, Ghareb and Green River Formations. Hydrous pyrolysis of these samples yields large amounts of Pr and Ph carbon skeletons, indicating that their precursors are predominantly sequestered in high-molecular-weight fractions. However, chemical degradation of the polar fraction and the kerogen of the unheated samples generally does not release large amounts of Pr and Ph. Additional information on the precursors of Pr and Ph is obtained from flash pyrolysis analyses of kerogens and residues after hydrous pyrolysis and after chemical degradation. Multiple precursors for Pr and Ph are recognised in these three samples. The main increase of the Pr/Ph ratio with increasing maturation temperature, which is associated with strongly increasing amounts of Pr and Ph, is probably due to the higher amount of precursors of Pr compared to Ph, and not to the different timing of generation of Pr and Ph.A thermal and chemical degradation approach was followed to determine the precursors of pristane (Pr) and phytane (Ph) in samples from the Gessoso-solfifera, Ghareb and Green River Formations. Hydrous pyrolysis of these samples yields large amounts of Pr and Ph carbon skeletons, indicating that their precursors are predominantly sequestered in high-molecular-weight fractions. However, chemical degradation of the polar fraction and the kerogen of the unheated samples generally does not release large amounts of Pr and Ph. Additional information on the precursors of Pr and Ph is obtained from flash pyrolysis analyses of kerogens and residues after hydrous pyrolysis and after chemical degradation. Multiple precursors for Pr and Ph are recognised in these three samples. The main increase of the Pr/Ph ratio with increasing maturation temperature, which is associated with strongly increasing amounts of Pr and Ph, is probably due to the

Advanced Chemical Propulsion

NASA Technical Reports Server (NTRS)

Alexander, Leslie, Jr.

2006-01-01

Advanced Chemical Propulsion (ACP) provides near-term incremental improvements in propulsion system performance and/or cost. It is an evolutionary approach to technology development that produces useful products along the way to meet increasingly more demanding mission requirements while focusing on improving payload mass fraction to yield greater science capability. Current activities are focused on two areas: chemical propulsion component, subsystem, and manufacturing technologies that offer measurable system level benefits; and the evaluation of high-energy storable propellants with enhanced performance for in-space application. To prioritize candidate propulsion technology alternatives, a variety of propulsion/mission analyses and trades have been conducted for SMD missions to yield sufficient data for investment planning. They include: the Advanced Chemical Propulsion Assessment; an Advanced Chemical Propulsion System Model; a LOx-LH2 small pumps conceptual design; a space storables propellant study; a spacecraft cryogenic propulsion study; an advanced pressurization and mixture ratio control study; and a pump-fed vs. pressure-fed study.

Pediatric susceptibility to 18 industrial chemicals: a comparative analysis of newborn with young animals.

PubMed

Hasegawa, R; Hirata-Koizumi, M; Dourson, M; Parker, A; Hirose, A; Nakai, S; Kamata, E; Ema, M

2007-04-01

We comprehensively re-analyzed the toxicity data for 18 industrial chemicals from repeated oral exposures in newborn and young rats, which were previously published. Two new toxicity endpoints specific to this comparative analysis were identified, the first, the presumed no observed adverse effect level (pNOAEL) was estimated based on results of both main and dose-finding studies, and the second, the presumed unequivocally toxic level (pUETL) was defined as a clear toxic dose giving similar severity in both newborn and young rats. Based on the analyses of both pNOAEL and pUETL ratios between the different ages, newborn rats demonstrated greater susceptibility (at most 8-fold) to nearly two thirds of these 18 chemicals (mostly phenolic substances), and less or nearly equal sensitivity to the other chemicals. Exceptionally one chemical only showed toxicity in newborn rats. In addition, Benchmark Dose Lower Bound (BMDL) estimates were calculated as an alternative endpoint. Most BMDLs were comparable to their corresponding pNOAELs and the overall correlation coefficient was 0.904. We discussed how our results can be incorporated into chemical risk assessment approaches to protect pediatric health from direct oral exposure to chemicals.

Cigarette pack messages about toxic chemicals: a randomised clinical trial.

PubMed

Brewer, Noel T; Jeong, Michelle; Mendel, Jennifer R; Hall, Marissa G; Zhang, Dongyu; Parada, Humberto; Boynton, Marcella H; Noar, Seth M; Baig, Sabeeh A; Morgan, Jennifer C; Ribisl, Kurt M

2018-04-13

The USA can require tobacco companies to disclose information about harmful and potentially harmful chemicals in cigarette smoke, but the impact of these messages is uncertain. We sought to assess the effect of placing messages about toxic chemicals on smokers' cigarette packs. Participants were 719 adult cigarette smokers from California, USA, recruited from September 2016 through March 2017. We randomly assigned smokers to receive either factual messages about chemicals in cigarette smoke and their health harms (intervention) or messages about not littering cigarette butts (control) on the side of their cigarette packs for 3 weeks. The primary trial outcome was intention to quit smoking. In intent-to-treat analyses, smokers whose packs had chemical messages did not have higher intentions to quit smoking at the end of the trial than those whose packs had control messages (P=0.56). Compared with control messages, chemical messages led to higher awareness of the chemicals (28% vs 15%, P<0.001) and health harms (60% vs 52%, P=0.02) featured in the messages. In addition, chemical messages led to greater negative affect, thinking about the chemicals in cigarettes and the harms of smoking, conversations about the messages and forgoing a cigarette (all P<0.05). Chemical messages on cigarette packs did not lead to higher intentions to quit among smokers in our trial. However, chemical messages informed smokers of chemicals in cigarettes and harms of smoking, which directly supports their implementation and would be critical to defending the messages against cigarette company legal challenges. NCT02785484. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Chemical Warfare: Many Unanswered Questions.

DTIC Science & Technology

1983-04-29

of Defense DSB Defense Science Board GAO U.S. General Accounting Office IDA Institute for Defense Analyses JCS Joint Chiefs of Staff SIPRI Stockholm...Defense Science Board in 1980, DOD specifically asked it to review intelligence data on chemical warfare, and DSB’s 1981 report accordingly presents its...Defense Science Board report suggests, however, that its com- - ments are based on a composite of intelligence information on Soviet chemical warfare

GHGRP Chemicals Sector Industrial Profile

EPA Pesticide Factsheets

EPA's Greenhouse Gas Reporting Program periodically produces detailed profiles of the various industries that report under the program. The profiles available for download below contain detailed analyses for the Chemicals industry.

7 CFR 3201.103 - Gasoline fuel additives.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 15 2014-01-01 2014-01-01 false Gasoline fuel additives. 3201.103 Section 3201.103... Designated Items § 3201.103 Gasoline fuel additives. (a) Definition. Chemical agents added to gasoline to increase octane levels, improve lubricity, and provide engine cleaning properties to gasoline-fired engines...

Terminal Olefin Profiles and Phylogenetic Analyses of Olefin Synthases of Diverse Cyanobacterial Species.

PubMed

Zhu, Tao; Scalvenzi, Thibault; Sassoon, Nathalie; Lu, Xuefeng; Gugger, Muriel

2018-07-01

Cyanobacteria can synthesize alkanes and alkenes, which are considered to be infrastructure-compatible biofuels. In terms of physiological function, cyanobacterial hydrocarbons are thought to be essential for membrane flexibility for cell division, size, and growth. The genetic basis for the biosynthesis of terminal olefins (1-alkenes) is a modular type I polyketide synthase (PKS) termed olefin synthase (Ols). The modular architectures of Ols and structural characteristics of alkenes have been investigated only in a few species of the small percentage (approximately 10%) of cyanobacteria that harbor putative Ols pathways. In this study, investigations of the domains, modular architectures, and phylogenies of Ols in 28 cyanobacterial strains suggested distinctive pathway evolution. Structural feature analyses revealed 1-alkenes with three carbon chain lengths (C 15 , C 17 , and C 19 ). In addition, the total cellular fatty acid profile revealed the diversity of the carbon chain lengths, while the fatty acid feeding assay indicated substrate carbon chain length specificity of cyanobacterial Ols enzymes. Finally, in silico analyses suggested that the N terminus of the modular Ols enzyme exhibited characteristics typical of a fatty acyl-adenylate ligase (FAAL), suggesting a mechanism of fatty acid activation via the formation of acyl-adenylates. Our results shed new light on the diversity of cyanobacterial terminal olefins and a mechanism for substrate activation in the biosynthesis of these olefins. IMPORTANCE Cyanobacterial terminal olefins are hydrocarbons with promising applications as advanced biofuels. Despite the basic understanding of the genetic basis of olefin biosynthesis, the structural diversity and phylogeny of the key modular olefin synthase (Ols) have been poorly explored. An overview of the chemical structural traits of terminal olefins in cyanobacteria is provided in this study. In addition, we demonstrated by in vivo fatty acid feeding assays that

Nonindependence and sensitivity analyses in ecological and evolutionary meta-analyses.

PubMed

Noble, Daniel W A; Lagisz, Malgorzata; O'dea, Rose E; Nakagawa, Shinichi

2017-05-01

Meta-analysis is an important tool for synthesizing research on a variety of topics in ecology and evolution, including molecular ecology, but can be susceptible to nonindependence. Nonindependence can affect two major interrelated components of a meta-analysis: (i) the calculation of effect size statistics and (ii) the estimation of overall meta-analytic estimates and their uncertainty. While some solutions to nonindependence exist at the statistical analysis stages, there is little advice on what to do when complex analyses are not possible, or when studies with nonindependent experimental designs exist in the data. Here we argue that exploring the effects of procedural decisions in a meta-analysis (e.g. inclusion of different quality data, choice of effect size) and statistical assumptions (e.g. assuming no phylogenetic covariance) using sensitivity analyses are extremely important in assessing the impact of nonindependence. Sensitivity analyses can provide greater confidence in results and highlight important limitations of empirical work (e.g. impact of study design on overall effects). Despite their importance, sensitivity analyses are seldom applied to problems of nonindependence. To encourage better practice for dealing with nonindependence in meta-analytic studies, we present accessible examples demonstrating the impact that ignoring nonindependence can have on meta-analytic estimates. We also provide pragmatic solutions for dealing with nonindependent study designs, and for analysing dependent effect sizes. Additionally, we offer reporting guidelines that will facilitate disclosure of the sources of nonindependence in meta-analyses, leading to greater transparency and more robust conclusions. © 2017 John Wiley & Sons Ltd.

Flavour chemicals in electronic cigarette fluids.

PubMed

Tierney, Peyton A; Karpinski, Clarissa D; Brown, Jessica E; Luo, Wentai; Pankow, James F

2016-04-01

Most e-cigarette liquids contain flavour chemicals. Flavour chemicals certified as safe for ingestion by the Flavor Extracts Manufacturers Association may not be safe for use in e-cigarettes. This study identified and measured flavour chemicals in 30 e-cigarette fluids. Two brands of single-use e-cigarettes were selected and their fluids in multiple flavour types analysed by gas chromatography/mass spectrometry. For the same flavour types, and for selected confectionary flavours (eg, bubble gum and cotton candy), also analysed were convenience samples of e-cigarette fluids in refill bottles from local 'vape' shops and online retailers. In many liquids, total flavour chemicals were found to be in the ∼1-4% range (10-40 mg/mL); labelled levels of nicotine were in the range of 0.6-2.4% (6 to 24 mg/mL). A significant number of the flavour chemicals were aldehydes, a compound class recognised as 'primary irritants' of mucosal tissue of the respiratory tract. Many of the products contained the same flavour chemicals: vanillin and/or ethyl vanillin was found in 17 of the liquids as one of the top three flavour chemicals, and/or at ≥0.5 mg/mL. The concentrations of some flavour chemicals in e-cigarette fluids are sufficiently high for inhalation exposure by vaping to be of toxicological concern. Regulatory limits should be contemplated for levels of some of the more worrisome chemicals as well as for total flavour chemical levels. Ingredient labeling should also be required. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Novel poly(dimethylsiloxane) bonding strategy via room temperature "chemical gluing".

PubMed

Lee, Nae Yoon; Chung, Bong Hyun

2009-04-09

Here we propose a new scheme for bonding poly(dimethylsiloxane) (PDMS), namely, a "chemical gluing", at room temperature by anchoring chemical functionalities on the surfaces of PDMS. Aminosilane and epoxysilane are anchored separately on the surfaces of two PDMS substrates, the reaction of which are well-known to form a strong amine-epoxy bond, therefore acting as a chemical glue. The bonding is performed for 1 h at room temperature without employing heat. We characterize the surface properties and composition by contact angle measurement, X-ray photoelectron spectroscopy analysis, and fluorescence measurement to confirm the formation of surface functionalities and investigate the adhesion strength by means of pulling, tearing, and leakage tests. As confirmed by the above-mentioned analyses and tests, PDMS surfaces were successfully modified with amine and epoxy functionalities, and a bonding based on the amine-epoxy chemical gluing was successfully realized within 1 h at room temperature. The bonding was sufficiently robust to tolerate intense introduction of liquid whose per minute injection volume was almost 2000 times larger than the total internal volume of the microchannel used. In addition to the bonding of PDMS-PDMS homogeneous assembly, the bonding of the PDMS-poly(ethylene terephthalate) heterogeneous assembly was also examined. We also investigate the potential use of the multifunctionalized walls inside the microchannel, generated as a consequence of the chemical gluing, as a platform for the targeted immobilization.

Chemical and Thermal Analysis

NASA Technical Reports Server (NTRS)

Bulluck, J. W.; Rushing, R. A.

1995-01-01

During the past six months we have conducted significant research in several domains in order to clarify and understanding the aging and chemical failure mechanism of thermoplastics (PVDF or Tefzel) for pipes. We organized numerous analytical studies with methods including Fourier Transform Infrared Spectroscopy, Dynamic Mechanical Analysis, Differential Scanning Calorimetry, and Stress Relaxation experiments. In addition we have reanalyzed previous thermogravimetric data concerning the rate of deplasticization of Coflon pipe. We investigated a number of aged samples of both Tefzel and Coflon that were forwarded from MERL. We conducted stress relaxation experiments of Coflon pipe at several temperatures and determined an activation energy. We also examined the dynamic mechanical response PVDF during deplasticization and during methanol plasticization. We performed numerous DSC analyses to research the changing crystalline morphology. We have noted significant changes in crystallinity upon aging for both PVDF and Tefzel. Little variation in elemental composition was noted for many of the aged Coflon and Tefzel samples tested.

Lipids: From Chemical Structures, Biosynthesis, and Analyses to Industrial Applications.

PubMed

Li-Beisson, Yonghua; Nakamura, Yuki; Harwood, John

2016-01-01

Lipids are one of the major subcellular components, and play numerous essential functions. As well as their physiological roles, oils stored in biomass are useful commodities for a variety of biotechnological applications including food, chemical feedstocks, and fuel. Due to their agronomic as well as economic and societal importance, lipids have historically been subjected to intensive studies. Major current efforts are to increase the energy density of cell biomass, and/or create designer oils suitable for specific applications. This chapter covers some basic aspects of what one needs to know about lipids: definition, structure, function, metabolism and focus is also given on the development of modern lipid analytical tools and major current engineering approaches for biotechnological applications. This introductory chapter is intended to serve as a primer for all subsequent chapters in this book outlining current development in specific areas of lipids and their metabolism.

Unnecessary Chemicals

ERIC Educational Resources Information Center

Johnson, Anita

1978-01-01

Discusses the health hazards resulting from chemical additions of many common products such as cough syrups, food dyes, and cosmetics. Steps being taken to protect consumers from these health hazards are included. (MDR)

Changes in extra-virgin olive oil added with Lycium barbarum L. carotenoids during frying: Chemical analyses and metabolomic approach.

PubMed

Blasi, F; Rocchetti, G; Montesano, D; Lucini, L; Chiodelli, G; Ghisoni, S; Baccolo, G; Simonetti, M S; Cossignani, L

2018-03-01

In this work, an Italian extra-virgin olive oil (EVOO) sample and the same sample added with a carotenoid-rich nutraceutical extract from Lycium barbarum L. (EVOOCar) were subjected to a frying process to comparatively assess chemical and physical changes and heat stability. Oxidation progress was monitored by measuring oil quality changes such as peroxide value, free acidity, K232, K268, and fatty acid composition as well as minor compound content, phenols, α-tocopherol, and carotenoids. An UHPLC/QTOF-MS metabolomics approach discriminated the two oil samples based on their chemical changes during frying, identifying also the phenolic classes most exposed to statistically significant variations. Partial least square discriminant analysis and volcano analysis were applied together to identify the most significant markers allowing group separation. The decrease in total phenolic content was lower in EVOOCar than in EVOO during frying. Monounsaturated and polyunsaturated fatty acids showed a significant percentage loss, 3.7% and 17.2%, respectively, in EVOO after 180min frying at 180°C, while they remained constant or slightly changed in EVOOCar. Zeaxanthin added to the oil rapidly decreased during the frying process. These findings showed that the addition of a carotenoid extract from L. barbarum can help to improve the oxidative stability of extra-virgin olive oil. Copyright © 2017 Elsevier Ltd. All rights reserved.

Developmental neurotoxicity of industrial chemicals.

PubMed

Grandjean, P; Landrigan, P J

2006-12-16

Neurodevelopmental disorders such as autism, attention deficit disorder, mental retardation, and cerebral palsy are common, costly, and can cause lifelong disability. Their causes are mostly unknown. A few industrial chemicals (eg, lead, methylmercury, polychlorinated biphenyls [PCBs], arsenic, and toluene) are recognised causes of neurodevelopmental disorders and subclinical brain dysfunction. Exposure to these chemicals during early fetal development can cause brain injury at doses much lower than those affecting adult brain function. Recognition of these risks has led to evidence-based programmes of prevention, such as elimination of lead additives in petrol. Although these prevention campaigns are highly successful, most were initiated only after substantial delays. Another 200 chemicals are known to cause clinical neurotoxic effects in adults. Despite an absence of systematic testing, many additional chemicals have been shown to be neurotoxic in laboratory models. The toxic effects of such chemicals in the developing human brain are not known and they are not regulated to protect children. The two main impediments to prevention of neurodevelopmental deficits of chemical origin are the great gaps in testing chemicals for developmental neurotoxicity and the high level of proof required for regulation. New, precautionary approaches that recognise the unique vulnerability of the developing brain are needed for testing and control of chemicals.

27 CFR 19.303 - Addition of caramel to rum or brandy and addition of oak chips to spirits.

Code of Federal Regulations, 2012 CFR

2012-04-01

... or brandy and addition of oak chips to spirits. 19.303 Section 19.303 Alcohol, Tobacco Products and... rum or brandy and addition of oak chips to spirits. A proprietor may add caramel that has no material... oak chips that have not been treated with any chemical to packages of spirits prior to or after the...

27 CFR 19.303 - Addition of caramel to rum or brandy and addition of oak chips to spirits.

Code of Federal Regulations, 2014 CFR

2014-04-01

... or brandy and addition of oak chips to spirits. 19.303 Section 19.303 Alcohol, Tobacco Products and... rum or brandy and addition of oak chips to spirits. A proprietor may add caramel that has no material... oak chips that have not been treated with any chemical to packages of spirits prior to or after the...

27 CFR 19.303 - Addition of caramel to rum or brandy and addition of oak chips to spirits.

Code of Federal Regulations, 2011 CFR

2011-04-01

... or brandy and addition of oak chips to spirits. 19.303 Section 19.303 Alcohol, Tobacco Products and... rum or brandy and addition of oak chips to spirits. A proprietor may add caramel that has no material... oak chips that have not been treated with any chemical to packages of spirits prior to or after the...

27 CFR 19.303 - Addition of caramel to rum or brandy and addition of oak chips to spirits.

Code of Federal Regulations, 2013 CFR

2013-04-01

... or brandy and addition of oak chips to spirits. 19.303 Section 19.303 Alcohol, Tobacco Products and... rum or brandy and addition of oak chips to spirits. A proprietor may add caramel that has no material... oak chips that have not been treated with any chemical to packages of spirits prior to or after the...

Taking Multiple Exposure Into Account Can Improve Assessment of Chemical Risks.

PubMed

Clerc, Frédéric; Bertrand, Nicolas Jean Hyacinthe; La Rocca, Bénédicte

2017-12-15

During work, operators may be exposed to several chemicals simultaneously. Most exposure assessment approaches only determine exposure levels for each substance individually. However, such individual-substance approaches may not correctly estimate the toxicity of 'cocktails' of chemicals, as the toxicity of a cocktail may differ from the toxicity of substances on their own. This study presents an approach that can better take into account multiple exposure when assessing chemical risks. Almost 30000 work situations, monitored between 2005 and 2014 and recorded in two French databases, were analysed using MiXie software. The algorithms employed in MiXie can identify toxicological classes associated with several substances, based on the additivity of the selected effects of each substance. The results of our retrospective analysis show that MiXie was able to identify almost 20% more potentially hazardous situations than identified using a single-substance approach. It therefore appears essential to review the ways in which multiple exposure is taken into account during risk assessment. © The Author(s) 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

SALI chemical analysis of provided samples

NASA Technical Reports Server (NTRS)

Becker, Christopher H.

1993-01-01

SRI has completed the chemical analysis of all the samples supplied by NASA. The final batch of four samples consisted of: one inch diameter MgF2 mirror, control 1200-ID-FL3; one inch diameter neat resin, PMR-15, AO171-IV-55, half exposed and half unexposed; one inch diameter chromic acid anodized, EOIM-3 120-47 aluminum disc; and AO-exposed and unexposed samples of fullerene extract material in powdered form, pressed into In foil for analysis. Chemical analyses of the surfaces were performed by the surface analysis by laser ionization (SALI) method. The analyses emphasize surface contamination or general organic composition. SALI uses nonselective photoionization of sputtered or desorbed atoms and molecules above but close (approximately one mm) to the surface, followed by time-of-flight (TOF) mass spectrometry. In these studies, we used laser-induced desorption by 5-ns pulse-width 355-nm light (10-100 mJ/sq cm) and single-photon ionization (SPI) by coherent 118-nm radiation (at approximately 5 x 10(exp 5) W/sq cm). SPI was chosen primarily for its ability to obtain molecular information, whereas multiphoton ionization (not used in the present studies) is intended primarily for elemental and small molecule information. In addition to these four samples, the Au mirror (EOIM-3 200-11, sample four) was depth profiled again. Argon ion sputtering was used together with photoionization with intense 355-nm radiation (35-ps pulsewidths). Depth profiles are similar to those reported earlier, showing reproducibility. No chromium was found in the sample above noise level; its presence could at most be at the trace level. Somewhat more Ni appears to be present in the Au layer in the unexposed side, indicating thermal diffusion without chemical enhancement. The result of the presence of oxygen is apparently to tie-up/draw out the Ni as an oxide at the surface. The exposed region has a brownish tint appearance to the naked eye.

Composition and Chemical Stability of Motor Fuels,

DTIC Science & Technology

Fuels, *Hydrocarbons, Cycloalkanes, Chemical analysis, Gasoline, Diesel fuels, Fuel additives, Chemical reactions, Stability, Jet engine fuels...Aviation gasoline, Aviation fuels, Chemical composition, Aromatic hydrocarbons, Unsaturated hydrocarbons, Storage, USSR, Translations, Fuel systems, Alkanes

An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling.

PubMed

Hahladakis, John N; Velis, Costas A; Weber, Roland; Iacovidou, Eleni; Purnell, Phil

2018-02-15

Over the last 60 years plastics production has increased manifold, owing to their inexpensive, multipurpose, durable and lightweight nature. These characteristics have raised the demand for plastic materials that will continue to grow over the coming years. However, with increased plastic materials production, comes increased plastic material wastage creating a number of challenges, as well as opportunities to the waste management industry. The present overview highlights the waste management and pollution challenges, emphasising on the various chemical substances (known as "additives") contained in all plastic products for enhancing polymer properties and prolonging their life. Despite how useful these additives are in the functionality of polymer products, their potential to contaminate soil, air, water and food is widely documented in literature and described herein. These additives can potentially migrate and undesirably lead to human exposure via e.g. food contact materials, such as packaging. They can, also, be released from plastics during the various recycling and recovery processes and from the products produced from recyclates. Thus, sound recycling has to be performed in such a way as to ensure that emission of substances of high concern and contamination of recycled products is avoided, ensuring environmental and human health protection, at all times. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Analysis of hydraulic fracturing additives by LC/Q-TOF-MS.

PubMed

Ferrer, Imma; Thurman, E Michael

2015-08-01

The chemical additives used in fracturing fluids can be used as tracers of water contamination caused by hydraulic fracturing operations. For this purpose, a complete chemical characterization is necessary using advanced analytical techniques. Liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC/Q-TOF-MS) was used to identify chemical additives present in flowback and produced waters. Accurate mass measurements of main ions and fragments were used to characterize the major components of fracking fluids. Sodium adducts turned out to be the main molecular adduct ions detected for some additives due to oxygen-rich structures. Among the classes of chemical components analyzed by mass spectrometry include gels (guar gum), biocides (glutaraldehyde and alkyl dimethyl benzyl ammonium chloride), and surfactants (cocamidopropyl dimethylamines, cocamidopropyl hydroxysultaines, and cocamidopropyl derivatives). The capabilities of accurate mass and MS-MS fragmentation are explored for the unequivocal identification of these compounds. A special emphasis is given to the mass spectrometry elucidation approaches used to identify a major class of hydraulic fracturing compounds, surfactants.

Cumulative effects of anti-androgenic chemical mixtures and ...

EPA Pesticide Factsheets

Kembra L. Howdeshell and L. Earl Gray, Jr.Toxicological studies of defined chemical mixtures assist human health risk assessment by characterizing the joint action of chemicals. This presentation will review the effects of anti-androgenic chemical mixtures on reproductive tract development in rats with a special focus on the reproductive toxicant phthalates. Observed mixture data are compared to mathematical mixture model predictions to determine how the individual chemicals in a mixture interact (e.g., response addition – probabilities of response for each individual chemical are added; dose-addition – the doses of each individual chemical at a given mixture dose are combined together based on the relative potency of the individual chemicals). Phthalate mixtures are observed to act in a dose-additive manner based on the relative potency of the individual phthalates to suppress fetal testosterone production. Similar dose-additive effects have been reported for mixtures of phthalates with anti-androgenic pesticides of differing mechanisms. Data from these phthalate experiments in rats can be used in conjunction with human biomonitoring data to determine individual hazard ratios. Furthermore, data from the toxicological studies can inform the analysis of human biomonitoring data on the association of detected chemicals and their metabolites with measured health outcomes. Data from phthalate experiments in rats can be used in conjunction with human biomonit

Analysing and Navigating Natural Products Space for Generating Small, Diverse, But Representative Chemical Libraries.

PubMed

O'Hagan, Steve; Kell, Douglas B

2018-01-01

Armed with the digital availability of two natural products libraries, amounting to some 195 885 molecular entities, we ask the question of how we can best sample from them to maximize their "representativeness" in smaller and more usable libraries of 96, 384, 1152, and 1920 molecules. The term "representativeness" is intended to include diversity, but for numerical reasons (and the likelihood of being able to perform a QSAR) it is necessary to focus on areas of chemical space that are more highly populated. Encoding chemical structures as fingerprints using the RDKit "patterned" algorithm, we first assess the granularity of the natural products space using a simple clustering algorithm, showing that there are major regions of "denseness" but also a great many very sparsely populated areas. We then apply a "hybrid" hierarchical K-means clustering algorithm to the data to produce more statistically robust clusters from which representative and appropriate numbers of samples may be chosen. There is necessarily again a trade-off between cluster size and cluster number, but within these constraints, libraries containing 384 or 1152 molecules can be found that come from clusters that represent some 18 and 30% of the whole chemical space, with cluster sizes of, respectively, 50 and 27 or above, just about sufficient to perform a QSAR. By using the online availability of molecules via the Molport system (www.molport.com), we are also able to construct (and, for the first time, provide the contents of) a small virtual library of available molecules that provided effective coverage of the chemical space described. Consistent with this, the average molecular similarities of the contents of the libraries developed is considerably smaller than is that of the original libraries. The suggested libraries may have use in molecular or phenotypic screening, including for determining possible transporter substrates. © 2017 The Authors. Biotechnology Journal Published by Wiley

Chemical composition studies of flint with different origins

NASA Astrophysics Data System (ADS)

Zarina, Liga; Seglins, Valdis; Kostjukovs, Juris; Burlakovs, Juris

2015-04-01

Flint is a widely used material in the Stone Age because of its physical characteristics, which makes the material suitable for obtaining tools with sharp working edges. Chert, flint, chalcedony, agate and jasper in composition and several other physical characteristics are very similar. Therefore in archaeology most often they are determined simplified and are not distinguished, but described as flint or chert, denoting only the material in a general sense. However, in-depth studies it is necessary accurately identify the rock type and, in addition, to determine the origin of the flint and the conditions of the formation for the various archaeological research needs. As a typical example can be noted the localization problems in determining whether flint is local, or have emerged in the region through the exchange or by transportation. Flint consists mainly from quartz and mostly it has cryptocrystalline or amorphous structure. In nature it occurs as nodules and interbedded inclusions in sedimentary deposits as a result of digenesis processes when calcium carbonate is replaced with silicia. Bedded chert primarily is accumulations originated from excess alkalinity in the sediments. Flint can also be formed in the crystallization processes of the chemically unstable amorphous silicia. In this context, it should be noted that flint is naturally heterogeneous and very varied material by the physical properties and therefore problematic in many contemporary studies. In the study different origin flint samples from England, Denmark and Latvia were compared after their chemical composition. Flint nodules from Northern Europe chalk cliffs formed as inclusions in interbedded deposits or results of the digenesis and samples of chalcedony saturated dolomite from Latvia formed in hydrothermal processes were analysed using XRD and XRF methods. The obtained data were statistically analysed, identifying major, minor and trace elements and subsequently assessing the chemical

Tough, High-Performance, Thermoplastic Addition Polymers

NASA Technical Reports Server (NTRS)

Pater, Ruth H.; Proctor, K. Mason; Gleason, John; Morgan, Cassandra; Partos, Richard

1991-01-01

Series of addition-type thermoplastics (ATT's) exhibit useful properties. Because of their addition curing and linear structure, ATT polymers have toughness, like thermoplastics, and easily processed, like thermosets. Work undertaken to develop chemical reaction forming stable aromatic rings in backbone of ATT polymer, combining high-temperature performance and thermo-oxidative stability with toughness and easy processibility, and minimizing or eliminating necessity for tradeoffs among properties often observed in conventional polymer syntheses.

An Additive Definition of Molecular Complexity.

PubMed

Böttcher, Thomas

2016-03-28

A framework for molecular complexity is established that is based on information theory and consistent with chemical knowledge. The resulting complexity index Cm is derived from abstracting the information content of a molecule by the degrees of freedom in the microenvironments on a per-atom basis, allowing the molecular complexity to be calculated in a simple and additive way. This index allows the complexity of any molecule to be universally assessed and is sensitive to stereochemistry, heteroatoms, and symmetry. The performance of this complexity index is evaluated and compared against the current state of the art. Its additive character gives consistent values also for very large molecules and supports direct comparisons of chemical reactions. Finally, this approach may provide a useful tool for medicinal chemistry in drug design and lead selection, as demonstrated by correlating molecular complexities of antibiotics with compound-specific parameters.

Non-autoclaved aerated concrete with mineral additives

NASA Astrophysics Data System (ADS)

Il'ina, L. V.; Rakov, M. A.

2016-01-01

We investigated the effect of joint grinding of Portland cement clinker, silica and carbonate components and mineral additives to specific surface of 280 - 300 m2/kg on the properties (strength, average density and thermal conductivity) of non-autoclaved aerated concrete, and the porosity of the hardened cement paste produced from Portland cement clinker with mineral additives. The joint grinding of the Portland cement clinker with silica and carbonate components and mineral additives reduces the energy consumption of non-autoclaved aerated concrete production. The efficiency of mineral additives (diopside, wollastonite) is due to the closeness the composition, the type of chemical bonds, physical and chemical characteristics (specific enthalpy of formation, specific entropy) to anhydrous clinker minerals and their hydration products. Considering the influence of these additions on hydration of clinker minerals and formation of hardened cement paste structure, dispersed wollastonite and diopside should be used as mineral additives. The hardness and, consequently, the elastic modulus of diopside are higher than that of hardened cement paste. As a result, there is a redistribution of stresses in the hardened cement paste interporous partitions and hardening, both the partitions and aerated concrete on the whole. The mineral additives introduction allowed to obtain the non-autoclaved aerated concrete with average density 580 kg/m3, compressive strength of 3.3 MPa and thermal conductivity of 0.131 W/(m.°C).

[Developmental neurotoxicity of industrial chemicals].

PubMed

Labie, Dominique

2007-10-01

"A Silent Pandemic : Industrial Chemicals Are Impairing the Brain Development of Children Worldwide" Fetal and early childhood exposures to industrial chemicals in the environment can damage the developing brain and can lead to neurodevelopmental disorders (NDDs)--autism, attention deficit disorder (ADHD), and mental retardation. In a new review study, published in The Lancet, Philip Grandjean and Philip Landrigan from the Harvard School of Public Health systematically examined publicly available data on chemical toxicity in order to identify the industrial chemicals that are the most likely to damage the developing brain. The researchers found that 202 industrial chemicals have the capacity to damage the human brain, and they conclude that chemical pollution may have harmed the brains of millions of children worldwide. The authors conclude further that the toxic effects of industrial chemicals on children have generally been overlooked. In North Amercia, the commission for environmental cooperation, and in European Union the DEVNERTOX projects had reached to the same conclusions. We analyse this review and discuss these rather pessimistic conclusions.

Microbial community diversity patterns are related to physical and chemical differences among temperate lakes near Beaver Island, MI

PubMed Central

Hengy, Miranda H.; Horton, Dean J.; Uzarski, Donald G.

2017-01-01

Lakes are dynamic and complex ecosystems that can be influenced by physical, chemical, and biological processes. Additionally, individual lakes are often chemically and physically distinct, even within the same geographic region. Here we show that differences in physicochemical conditions among freshwater lakes located on (and around) the same island, as well as within the water column of each lake, are significantly related to aquatic microbial community diversity. Water samples were collected over time from the surface and bottom-water within four freshwater lakes located around Beaver Island, MI within the Laurentian Great Lakes region. Three of the sampled lakes experienced seasonal lake mixing events, impacting either O2, pH, temperature, or a combination of the three. Microbial community alpha and beta diversity were assessed and individual microbial taxa were identified via high-throughput sequencing of the 16S rRNA gene. Results demonstrated that physical and chemical variability (temperature, dissolved oxygen, and pH) were significantly related to divergence in the beta diversity of surface and bottom-water microbial communities. Despite its correlation to microbial community structure in unconstrained analyses, constrained analyses demonstrated that dissolved organic carbon (DOC) concentration was not strongly related to microbial community structure among or within lakes. Additionally, several taxa were correlated (either positively or negatively) to environmental variables, which could be related to aerobic and anaerobic metabolisms. This study highlights the measurable relationships between environmental conditions and microbial communities within freshwater temperate lakes around the same island. PMID:29062609

Characterization of chemical interactions during chemical mechanical polishing (CMP) of copper

NASA Astrophysics Data System (ADS)

Lee, Seung-Mahn

2003-10-01

Chemical mechanical polishing (CMP) has received much attention as an unique technique to provide a wafer level planarization in semiconductor manufacturing. However, despite the extensive use of CMP, it still remains one of the least understood areas in semiconductor processing. The lack of the fundamental understanding is a significant barrier to further advancements in CMP technology. One critical aspect of metal CMP is the formation of a thin surface layer on the metal surface. The formation and removal of this layer controls all the aspects of the CMP process, including removal rate, surface finish, etc. In this dissertation, we focus on the characterization of the formation and removal of the thin surface layer on the copper surface. The formation dynamics was investigated using static and dynamic electrochemical techniques, including potentiodynamic scans and chronoamperometry. The results were validated using XPS measurements. The mechanical properties of the surface layer were investigated using nanoindentation measurements. The electrochemical investigation showed that the thickness of the surface layer is controlled by the chemicals such as an oxidizer (hydrogen peroxide), a corrosion inhibitor (benzotriazole), a complexing agent (citric acid), and their concentrations. The dynamic electrochemical measurements indicated that the initial layer formation kinetics is unaffected by the corrosion inhibitors. The passivation due to the corrosion inhibitor becomes important only on large time scales (>200 millisecond). The porosity and the density of the chemically modified surface layer can be affected by additives of other chemicals such as citric acid. An optimum density of the surface layer is required for high polishing rate while at the same time maintaining a high degree of surface finish. Nanoindentation measurements indicated that the mechanical properties of the surface layer are strongly dependent on the chemical additives in the slurry. The CMP

Evaluation of C60 secondary ion mass spectrometry for the chemical analysis and imaging of fingerprints.

PubMed

Sisco, Edward; Demoranville, Leonard T; Gillen, Greg

2013-09-10

The feasibility of using C60(+) cluster primary ion bombardment secondary ion mass spectrometry (C60(+) SIMS) for the analysis of the chemical composition of fingerprints is evaluated. It was found that C60(+) SIMS could be used to detect and image the spatial localization of a number of sebaceous and eccrine components in fingerprints. These analyses were also found to not be hindered by the use of common latent print powder development techniques. Finally, the ability to monitor the depth distribution of fingerprint constituents was found to be possible - a capability which has not been shown using other chemical imaging techniques. This paper illustrates a number of strengths and potential weaknesses of C60(+) SIMS as an additional or complimentary technique for the chemical analysis of fingerprints. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Phenylethynyl Containing Reactive Additives

NASA Technical Reports Server (NTRS)

Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

2002-01-01

Phenylethynyl containing reactive additives were prepared from aromatic diamines containing phenylethynyl groups and various ratios of phthalic anhydride and 4-phenylethynylphthalic anhydride in glacial acetic acid to form the imide in one step or in N-methyl-2-pyrrolidi none to form the amide acid intermediate. The reactive additives were mixed in various amounts (10% to 90%) with oligomers containing either terminal or pendent phenylethynyl groups (or both) to reduce the melt viscosity and thereby enhance processability. Upon thermal cure, the additives react and become chemically incorporated into the matrix and effect an increase in crosslink density relative to that of the host resin. This resultant increase in crosslink density has advantageous consequences on the cured resin properties such as higher glass transition temperature and higher modulus as compared to that of the host resin.

Phenylethynyl Containing Reactive Additives

NASA Technical Reports Server (NTRS)

Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

2002-01-01

Phenylethynyl containing reactive additives were prepared from aromatic diamine, containing phenylethvnvl groups and various ratios of phthalic anhydride and 4-phenylethynviphthalic anhydride in glacial acetic acid to form the imide in one step or in N-methyl-2-pvrrolidinone to form the amide acid intermediate. The reactive additives were mixed in various amounts (10% to 90%) with oligomers containing either terminal or pendent phenylethynyl groups (or both) to reduce the melt viscosity and thereby enhance processability. Upon thermal cure, the additives react and become chemically incorporated into the matrix and effect an increase in crosslink density relative to that of the host resin. This resultant increase in crosslink density has advantageous consequences on the cured resin properties such as higher glass transition temperature and higher modulus as compared to that of the host resin.

New directions: Atmospheric chemical mechanisms for the future

EPA Science Inventory

The chemical reaction scheme or mechanism used to represent atmospheric chemical reactions is at the heart of each air quality model used in research and policy applications to predict and analyse the complex air pollutants: ozone, air toxics and PM2.5. This is necessarily only a...

Physical-chemical evaluation of hydraulic fracturing chemicals in the context of produced water treatment.

PubMed

Camarillo, Mary Kay; Domen, Jeremy K; Stringfellow, William T

2016-12-01

Produced water is a significant waste stream that can be treated and reused; however, the removal of production chemicals-such as those added in hydraulic fracturing-must be addressed. One motivation for treating and reusing produced water is that current disposal methods-typically consisting of deep well injection and percolation in infiltration pits-are being limited. Furthermore, oil and gas production often occurs in arid regions where there is demand for new water sources. In this paper, hydraulic fracturing chemical additive data from California are used as a case study where physical-chemical and biodegradation data are summarized and used to screen for appropriate produced water treatment technologies. The data indicate that hydraulic fracturing chemicals are largely treatable; however, data are missing for 24 of the 193 chemical additives identified. More than one-third of organic chemicals have data indicating biodegradability, suggesting biological treatment would be effective. Adsorption-based methods and partitioning of chemicals into oil for subsequent separation is expected to be effective for approximately one-third of chemicals. Volatilization-based treatment methods (e.g. air stripping) will only be effective for approximately 10% of chemicals. Reverse osmosis is a good catch-all with over 70% of organic chemicals expected to be removed efficiently. Other technologies such as electrocoagulation and advanced oxidation are promising but lack demonstration. Chemicals of most concern due to prevalence, toxicity, and lack of data include propargyl alcohol, 2-mercaptoethyl alcohol, tetrakis hydroxymethyl-phosphonium sulfate, thioglycolic acid, 2-bromo-3-nitrilopropionamide, formaldehyde polymers, polymers of acrylic acid, quaternary ammonium compounds, and surfactants (e.g. ethoxylated alcohols). Future studies should examine the fate of hydraulic fracturing chemicals in produced water treatment trains to demonstrate removal and clarify interactions

Results of chemical analyses of soil, shale, and soil/shale extract from the Mancos Shale formation in the Gunnison Gorge National Conservation Area, southwestern Colorado, and at Hanksville, Utah

USGS Publications Warehouse

Tuttle, Michele L.W.; Fahy, Juli; Grauch, Richard I.; Ball, Bridget A.; Chong, Geneva W.; Elliott, John G.; Kosovich, John J.; Livo, Keith E.; Stillings, Lisa L.

2007-01-01

Results of chemical and some isotopic analyses of soil, shale, and water extracts collected from the surface, trenches, and pits in the Mancos Shale are presented in this report. Most data are for sites on the Gunnison Gorge National Conservation Area (GGNCA) in southwestern Colorado. For comparison, data from a few sites from the Mancos landscape near Hanksville, Utah, are included. Twelve trenches were dug on the GGNCA from which 258 samples for whole-rock (total) analyses and 187 samples for saturation paste extracts were collected. Sixteen of the extract samples were duplicated and subjected to a 1:5 water extraction for comparison. A regional soil survey across the Mancos landscape on the GGNCA generated 253 samples for whole-rock analyses and saturation paste extractions. Seventeen gypsum samples were collected on the GGNCA for sulfur and oxygen isotopic analysis. Sixteen samples were collected from shallow pits in the Mancos Shale near Hanksville, Utah.

Reduction of dioxin-like toxicity in effluents by additional wastewater treatment and related effects in fish.

PubMed

Maier, Diana; Benisek, Martin; Blaha, Ludek; Dondero, Francesco; Giesy, John P; Köhler, Heinz-R; Richter, Doreen; Scheurer, Marco; Triebskorn, Rita

2016-10-01

Efficiency of advanced wastewater treatment technologies to reduce micropollutants which mediate dioxin-like toxicity was investigated. Technologies compared included ozonation, powdered activated carbon and granular activated carbon. In addition to chemical analyses in samples of effluents, surface waters, sediments, and fish, (1) dioxin-like potentials were measured in paired samples of effluents, surface waters, and sediments by use of an in vitro biotest (reporter gene assay) and (2) dioxin-like effects were investigated in exposed fish by use of in vivo activity of the mixed-function, monooxygenase enzyme, ethoxyresorufin O-deethylase (EROD) in liver. All advanced technologies studied, based on degradation or adsorption, significantly reduced dioxin-like potentials in samples and resulted in lesser EROD activity in livers of fish. Results of in vitro and in vivo biological responses were not clearly related to quantification of targeted analytes by use of instrumental analyses. Copyright © 2016 Elsevier Inc. All rights reserved.

Results of mineral, chemical, and sulfate isotopic analyses of water, soil, rocks, and soil extracts from the Pariette Draw Watershed, Uinta Basin, Utah

USGS Publications Warehouse

Morrison, Jean M.; Tuttle, Michele L.W.; Fahy, Juli W.

2015-08-06

The goal of this study was to establish a process-based understanding of salt, Se, and B behavior to address whether these contaminants can be better managed, or if uncontrollable natural processes will overwhelm any attempts to bring Pariette Draw into compliance with respect to recently established total maximum daily limits (TMDLs). We collected data to refine our knowledge about the role of rock weathering and soil formation in the transport and storage of salt in the watershed and to show how salt is cycled under irrigated and natural conditions. Our approach was to sample rock, soils, and sediment on irrigated and natural terrain for mineralogical analysis to determine the residence of salt and associated Se and B, classify minerals as primary (related to rock formation) or secondary weathering products, and characterize mineral dissolution kinetics. Mineral and chemical analyses and selective extractions of rocks and soils provide useful information in understanding solute movement and mineral dissolution/ formation. The resulting data are critical in determining residence of salt, Se, and B in weathered rock and soil and understanding the mobility during water-rock-soil interactions. This report summarizes our methods for sample and data collection and tabulates the mineral, chemical, and isotopic data collected.

Exploring the hydraulic fracturing parameter space: a novel high-pressure, high-throughput reactor system for investigating subsurface chemical transformations.

PubMed

Sumner, Andrew J; Plata, Desiree L

2018-02-21

Hydraulic fracturing coupled with horizontal drilling (HDHF) involves the deep-well injection of a fracturing fluid composed of diverse and numerous chemical additives designed to facilitate the release and collection of natural gas from shale plays. Analyses of flowback wastewaters have revealed organic contamination from both geogenic and anthropogenic sources. The additional detections of undisclosed halogenated chemicals suggest unintended in situ transformation of reactive additives, but the formation pathways for these are unclear in subsurface brines. To develop an efficient experimental framework for investigating the complex shale-well parameter space, we have reviewed and synthesized geospatial well data detailing temperature, pressure, pH, and halide ion values as well as industrial chemical disclosure and concentration data. Our findings showed subsurface conditions can reach pressures up to 4500 psi (310 bars) and temperatures up to 95 °C, while at least 588 unique chemicals have been disclosed by industry, including reactive oxidants and acids. Given the extreme conditions necessary to simulate the subsurface, we briefly highlighted existing geochemical reactor systems rated to the necessary pressures and temperatures, identifying throughput as a key limitation. In response, we designed and developed a custom reactor system capable of achieving 5000 psi (345 bars) and 90 °C at low cost with 15 individual reactors that are readily turned over. To demonstrate the system's throughput, we simultaneously tested 12 disclosed HDHF chemicals against a radical initiator compound in simulated subsurface conditions, ruling out a dozen potential transformation pathways in a single experiment. This review outlines the dynamic and diverse parameter range experienced by HDHF chemical additives and provides an optimized framework and novel reactor system for the methodical study of subsurface transformation pathways. Ultimately, enabling such studies will provide

Intrinsic dependence of the magnetic properties of CoFe2O4 nanoparticles prepared via chemical methods with addition of chelating agents

NASA Astrophysics Data System (ADS)

Mendonça, E. C.; Tenório, Mayara A.; Mecena, S. G.; Zucolotto, B.; Silva, L. S.; Jesus, C. B. R.; Meneses, C. T.; Duque, J. G. S.

2015-12-01

In this work, the effect of addition of different chelating agents on the magnetic properties of cobalt ferrite nanoparticles produced by the combining of both co-precipitation and hydrothermal methods is reported. The Rietveld analyses of X-ray diffraction patterns reveal that our samples are single phase (space group: Fd-3m) with small average sizes. The weight losses observed in the thermogravimetric measurements together with the M×H curves show that the organic contamination coming from chelating agent decomposition can give rise to misinterpretation of the magnetization measurements. Besides, analyses of the zero-field-cooled (ZFC) and field-cooled (FC) magnetization measurements and the M×H curves measured at room temperature allows us to state that both the average blocking temperature and particles size distribution are sensitive to the kind of chelating agent.

Exposure Levels for Chemical Threat Compounds; Information to Facilitate Chemical Incident Response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hauschild, Veronique; Watson, Annetta Paule

2013-01-01

Exposure Standards, Limits and Guidelines for Chemical Threat Compunds ABSTRACT Exposure criteria for chemical warfare (CW) agents and certain toxic industrial chemicals (TICs) used as CW agents (such as chlorine fill in an improvised explosive device) have been developed for protection of the civilian general public, civilian employees in chemical agent processing facilities and deployed military populations. In addition, compound-specific concentrations have been developed to serve as how clean is clean enough clearance criteria guiding facility recovery following chemical terrorist or other hazardous release events. Such criteria are also useful to verify compound absence, identify containment boundaries and expedite facilitymore » recovery following chemical threat release. There is no single right value or concentration appropriate for all chemical hazard control applications. It is acknowledged that locating and comparing the many sources of CW agent and TIC exposure criteria has not been previously well-defined. This paper summarizes many of these estimates and assembles critical documentation regarding their derivation and use.« less

Environmental Fate and Ecological Impact of Emerging Energetic Chemicals (ADN, DNAN and its Amino-Derivatives, PETN, NTO, NQ, FOX-7, and FOX-12) and an Insensitive Formulation

DTIC Science & Technology

2014-07-01

the two soils [12,32]. Chemical analyses of test soil (Fig. 4A) and earthworm tissue (Fig. 4B) showed that addition of earthworms to soil aided in...the soil DNAN concentration (30 mg/kg, measured prior to addition of earthworms to test soils). 3.0 ECOTOXICOLOGY OF NTO, NQ, FOX-7, AND FOX-12... addition , Sarlauska et al. [40] examined the toxicity of NTO by looking at selected enzymes isolated from pig, or a virus-transformed lamb kidney

The potential for chemical evolution on Titan

NASA Technical Reports Server (NTRS)

Beauchamp, P. M.; Lunine, J. I.; Welch, C.

2002-01-01

Sampling of organics to determine oxygen content, extent of acetylene polymerization, existence of chiral molecules and enantiomeric excesses, and searches for specific polymer products, would be of interest in assessing how organic chemistry evolves toward biochemistry. Such efforts would require fairly sophisticated chemical analyses from landed missions. This paper examines this chemistry and the potential instruments that could distinguish chemical evolution.

Double quick, double click reversible peptide “stapling”† †Electronic supplementary information (ESI) available: Synthesis and characterization, additional biophysical and biochemical analyses. See DOI: 10.1039/c7sc01342f Click here for additional data file. Click here for additional data file. Click here for additional data file.

PubMed Central

Grison, Claire M.; Burslem, George M.; Miles, Jennifer A.; Pilsl, Ludwig K. A.; Yeo, David J.; Imani, Zeynab; Warriner, Stuart L.; Webb, Michael E.

2017-01-01

The development of constrained peptides for inhibition of protein–protein interactions is an emerging strategy in chemical biology and drug discovery. This manuscript introduces a versatile, rapid and reversible approach to constrain peptides in a bioactive helical conformation using BID and RNase S peptides as models. Dibromomaleimide is used to constrain BID and RNase S peptide sequence variants bearing cysteine (Cys) or homocysteine (hCys) amino acids spaced at i and i + 4 positions by double substitution. The constraint can be readily removed by displacement of the maleimide using excess thiol. This new constraining methodology results in enhanced α-helical conformation (BID and RNase S peptide) as demonstrated by circular dichroism and molecular dynamics simulations, resistance to proteolysis (BID) as demonstrated by trypsin proteolysis experiments and retained or enhanced potency of inhibition for Bcl-2 family protein–protein interactions (BID), or greater capability to restore the hydrolytic activity of the RNAse S protein (RNase S peptide). Finally, use of a dibromomaleimide functionalized with an alkyne permits further divergent functionalization through alkyne–azide cycloaddition chemistry on the constrained peptide with fluorescein, oligoethylene glycol or biotin groups to facilitate biophysical and cellular analyses. Hence this methodology may extend the scope and accessibility of peptide stapling. PMID:28970902

The regulatory use of the Local Lymph Node Assay for the notification of new chemicals in Europe.

PubMed

Angers-Loustau, Alexandre; Tosti, Luca; Casati, Silvia

2011-08-01

The regulatory use of the Local Lymph Node Assay (LLNA) for new chemicals registration was monitored by screening the New Chemicals Database (NCD), which was managed by the former European Chemicals Bureau (ECB) at the European Commission Joint Research Centre (JRC). The NCD centralised information for chemicals notified after 1981, where toxicological information has been generated predominantly according to approved test methods. The database was searched to extract notifications for which the information for skin sensitisation labelling was based on results derived with the LLNA. The details of these records were extracted and pooled, and evaluated with regard to the extent of use of the LLNA over time, as well as for analysing the information retrieved on critical aspects of the procedure e.g. strain and amount of animals used, lymph node processing, solvent and doses selected, stimulation indices, and for assessing their level of compliance to the OECD Test Guideline 429. In addition the accuracy of the reduced LLNA when applied to new chemicals was investigated. Copyright © 2011 Elsevier Inc. All rights reserved.

Using Additional Analyses to Clarify the Functions of Problem Behavior: An Analysis of Two Cases

ERIC Educational Resources Information Center

Payne, Steven W.; Dozier, Claudia L.; Neidert, Pamela L.; Jowett, Erica S.; Newquist, Matthew H.

2014-01-01

Functional analyses (FA) have proven useful for identifying contingencies that influence problem behavior. Research has shown that some problem behavior may only occur in specific contexts or be influenced by multiple or idiosyncratic variables. When these contexts or sources of influence are not assessed in an FA, further assessment may be…

X-ray diffraction and TGA kinetic analyses for chemical looping combustion applications.

PubMed

Tijani, Mansour Mohammedramadan; Aqsha, Aqsha; Mahinpey, Nader

2018-04-01

Synthesis and characterization of supported metal-based oxygen carriers were carried out to provide information related to the use of oxygen carriers for chemical looping combustion processes. The Cu, Co, Fe, Ni metals supported with Al 2 O 3 , CeO 2 , TiO 2 , ZrO 2 were prepared using the wetness impregnation technique. Then, the X-ray Diffraction (XRD) characterization of oxidized and reduced samples was obtained and presented. The kinetic analysis using Thermogravimetric analyzer (TGA) of the synthesized samples was conducted. The kinetics of reduction reaction of all samples were estimated and explained.

Method for Derivatization and Detection of Chemical Weapons Convention Related Sulfur Chlorides via Electrophilic Addition with 3-Hexyne.

PubMed

Goud, D Raghavender; Pardasani, Deepak; Purohit, Ajay Kumar; Tak, Vijay; Dubey, Devendra Kumar

2015-07-07

Sulfur monochloride (S2Cl2) and sulfur dichloride (SCl2) are important precursors of the extremely toxic chemical warfare agent sulfur mustard and classified, respectively, into schedule 3.B.12 and 3.B.13 of the Chemical Weapons Convention (CWC). Hence, their detection and identification is of vital importance for verification of CWC. These chemicals are difficult to detect directly using chromatographic techniques as they decompose and do not elute. Until now, the use of gas chromatographic approaches to follow the derivatized sulfur chlorides is not reported in the literature. The electrophilic addition reaction of sulfur monochloride and sulfur dichloride toward 3-hexyne was explored for the development of a novel derivatization protocol, and the products were subjected to gas chromatography-mass spectrometric (GC-MS) analysis. Among various unsaturated reagents like alkenes and alkynes, symmetrical alkyne 3-hexyne was optimized to be the suitable derivatizing agent for these analytes. Acetonitrile was found to be the suitable solvent for the derivatization reaction. The sample preparation protocol for the identification of these analytes from hexane spiked with petrol matrix was also optimized. Liquid-liquid extraction followed by derivatization was employed for the identification of these analytes from petrol matrix. Under the established conditions, the detection and quantification limits are 2.6 μg/mL, 8.6 μg/mL for S2Cl2 and 2.3 μg/mL, 7.7 μg/mL for SCl2, respectively, in selected ion monitoring (SIM) mode. The calibration curve had a linear relationship with y = 0.022x - 0.331 and r(2) = 0.992 for the working range of 10 to 500 μg/mL for S2Cl2 and y = 0.007x - 0.064 and r(2) = 0.991 for the working range of 10 to 100 μg/mL for SCl2, respectively. The intraday RSDs were between 4.80 to 6.41%, 2.73 to 6.44% and interday RSDs were between 2.20 to 7.25% and 2.34 to 5.95% for S2Cl2 and SCl2, respectively.

Coordinating Chemical and Mineralogical Analyses of Antarctic Dry Valley Sediments as Potential Analogs for Mars

NASA Technical Reports Server (NTRS)

Patel, S. N.; Bishop, J. L.; Englert, P.; Gibson, E. K.

2015-01-01

The Antarctic Dry Valleys (ADV) provide a unique terrestrial analog for Martian surface processes as they are extremely cold and dry sedimentary environments. The surface geology and the chemical composition of the Dry Valleys that are similar to Mars suggest the possible presence of these soil-formation processes on Mars. The soils and sediments from Wright Valley, Antarctica were investigated in this study to examine mineralogical and chemical changes along the surface layer in this region and as a function of depth. Surface samples collected near Prospect Mesa and Don Juan Pond of the ADV were analyzed using visible/near-infrared (VNIR) and mid-IR reflectance spectroscopy and major and trace element abundances.

A Novel Approach for Evaluating Carbamate Mixtures for Dose Additivity

EPA Science Inventory

Two mathematical approaches were used to test the hypothesis ofdose-addition for a binary and a seven-chemical mixture ofN-methyl carbamates, toxicologically similar chemicals that inhibit cholinesterase (ChE). In the more novel approach, mixture data were not included in the ana...

Mitigation of Humic Acid Inhibition in Anaerobic Digestion of Cellulose by Addition of Various Salts.

PubMed

Azman, Samet; Khadem, Ahmad F; Zeeman, Grietje; van Lier, Jules B; Plugge, Caroline M

2015-03-25

Humic compounds are inhibitory to the anaerobic hydrolysis of cellulosic biomass. In this study, the impact of salt addition to mitigate the inhibitory effects of humic compounds was investigated. The experiment was conducted using batch tests to monitor the anaerobic hydrolysis of cellulose in the presence of humic acid. Sodium, potassium, calcium, magnesium and iron salts were tested separately for their efficiency to mitigate humic acid inhibition. All experiments were done under mesophilic conditions (30 °C) and at pH 7. Methane production was monitored online, using the Automatic Methane Potential Test System. Methane production, soluble chemical oxygen demand and volatile fatty acid content of the samples were measured to calculate the hydrolysis efficiencies. Addition of magnesium, calcium and iron salts clearly mitigated the inhibitory effects of humic acid and hydrolysis efficiencies reached up to 75%, 65% and 72%, respectively, which were similar to control experiments. Conversely, potassium and sodium salts addition did not mitigate the inhibition and hydrolysis efficiencies were found to be less than 40%. Mitigation of humic acid inhibition via salt addition was also validated by inductively coupled plasma atomic emission spectroscopy analyses, which showed the binding capacity of different cations to humic acid.

Chemical quality of ground water in the central Sacramento Valley, California

USGS Publications Warehouse

Fogelman, Ronald P.

1978-01-01

The study area includes about 1,200 square miles in the central Sacramento Valley adjacent to the Sacramento River from Knights Landing to Los Molinos, Calif. With recent agricultural development in the area, additional land has been brought under irrigation from land which had been used primarily for dry farming and grazing. This report documents the chemical character of the ground water prior to water-level declines resulting from extensive pumping for irrigation or to changes caused by extensive use of imported surface water. Chemical analyses of samples from 209 wells show that most of the area is underlain by ground water of a quality suitable for most agricultural and domestic purposes. Most of the water sampled in the area has dissolved-solids concentrations ranging from 100 to 700 milligrams per liter. The general water types for the area are a calcium magnesium bicarbonate or magnesium calcium bicarbonate and there are negligible amounts of toxic trace elements. (Woodard-USGS)

Soil chemical sensor and precision agricultural chemical delivery system and method

DOEpatents

Colburn, Jr., John W.

1991-01-01

A real time soil chemical sensor and precision agricultural chemical delivery system includes a plurality of ground-engaging tools in association with individual soil sensors which measure soil chemical levels. The system includes the addition of a solvent which rapidly saturates the soil/tool interface to form a conductive solution of chemicals leached from the soil. A multivalent electrode, positioned within a multivalent frame of the ground-engaging tool, applies a voltage or impresses a current between the electrode and the tool frame. A real-time soil chemical sensor and controller senses the electrochemical reaction resulting from the application of the voltage or current to the leachate, measures it by resistivity methods, and compares it against pre-set resistivity levels for substances leached by the solvent. Still greater precision is obtained by calibrating for the secondary current impressed through solvent-less soil. The appropriate concentration is then found and the servo-controlled delivery system applies the appropriate amount of fertilizer or agricultural chemicals substantially in the location from which the soil measurement was taken.

Soil chemical sensor and precision agricultural chemical delivery system and method

DOEpatents

Colburn, J.W. Jr.

1991-07-23

A real time soil chemical sensor and precision agricultural chemical delivery system includes a plurality of ground-engaging tools in association with individual soil sensors which measure soil chemical levels. The system includes the addition of a solvent which rapidly saturates the soil/tool interface to form a conductive solution of chemicals leached from the soil. A multivalent electrode, positioned within a multivalent frame of the ground-engaging tool, applies a voltage or impresses a current between the electrode and the tool frame. A real-time soil chemical sensor and controller senses the electrochemical reaction resulting from the application of the voltage or current to the leachate, measures it by resistivity methods, and compares it against pre-set resistivity levels for substances leached by the solvent. Still greater precision is obtained by calibrating for the secondary current impressed through solvent-less soil. The appropriate concentration is then found and the servo-controlled delivery system applies the appropriate amount of fertilizer or agricultural chemicals substantially in the location from which the soil measurement was taken. 5 figures.

Chemical plant innovative safety investments decision-support methodology.

PubMed

Reniers, G L L; Audenaert, A

2009-01-01

This article examines the extent to which investing in safety during the creation of a new chemical installation proves profitable. The authors propose a management supporting cost-benefit model that identifies and evaluates investments in safety within a chemical company. This innovative model differentiates between serious accidents and less serious accidents, thus providing an authentic image of prevention-related costs and benefits. In classic cost-benefit analyses, which do not make such differentiations, only a rudimentary image of potential profitability resulting from investments in safety is obtained. The resulting management conclusions that can be drawn from such classical analyses are of a very limited nature. The proposed model, however, is applied to a real case study and the proposed investments in safety at an appointed chemical installation are weighed against the estimated hypothetical benefits resulting from the preventive measures to be installed at the installation. In the case-study carried out in question, it would appear that the proposed prevention investments are justified. Such an economic exercise may be very important to chemical corporations trying to (further) improve their safety investments.

Suspect Screening Analysis of Chemicals in Consumer Products.

PubMed

Phillips, Katherine A; Yau, Alice; Favela, Kristin A; Isaacs, Kristin K; McEachran, Andrew; Grulke, Christopher; Richard, Ann M; Williams, Antony J; Sobus, Jon R; Thomas, Russell S; Wambaugh, John F

2018-03-06

A two-dimensional gas chromatography-time-of-flight/mass spectrometry (GC×GC-TOF/MS) suspect screening analysis method was used to rapidly characterize chemicals in 100 consumer products-which included formulations (e.g., shampoos, paints), articles (e.g., upholsteries, shower curtains), and foods (cereals)-and therefore supports broader efforts to prioritize chemicals based on potential human health risks. Analyses yielded 4270 unique chemical signatures across the products, with 1602 signatures tentatively identified using the National Institute of Standards and Technology 2008 spectral database. Chemical standards confirmed the presence of 119 compounds. Of the 1602 tentatively identified chemicals, 1404 were not present in a public database of known consumer product chemicals. Reported data and model predictions of chemical functional use were applied to evaluate the tentative chemical identifications. Estimated chemical concentrations were compared to manufacturer-reported values and other measured data. Chemical presence and concentration data can now be used to improve estimates of chemical exposure, and refine estimates of risk posed to human health and the environment.

Chemical Shuttle Additives in Lithium Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patterson, Mary

2013-03-31

is higher than NMC) and the DDB is useful for lithium ion cells with LFP cathodes (potential that is lower than NMC). A 4.5 V class redox shuttle provided by Argonne National Laboratory was evaluated which provides a few cycles of overcharge protection for lithium ion cells containing NMC cathodes but it is not stable enough for consideration. Thus, a redox shuttle with an appropriate redox potential and sufficient chemical and electrochemical stability for commercial use in larger format lithium ion cells with NMC cathodes was not found. Molecular imprinting of the redox shuttle molecule during solid electrolyte interphase (SEI) layer formation likely contributes to the successful reduction of oxidized redox shuttle species at carbon anodes. This helps to understand how a carbon anode covered with an SEI layer, that is supposed to be electrically insulating, can reduce the oxidized form of a redox shuttle.« less

Role of chemical interaction between MgH2 and TiO2 additive on the hydrogen storage behavior of MgH2

NASA Astrophysics Data System (ADS)

Pukazhselvan, D.; Nasani, Narendar; Sandhya, K. S.; Singh, Budhendra; Bdikin, Igor; Koga, Nobuaki; Fagg, Duncan Paul

2017-10-01

The present study explores how the additive titania chemically reacts with magnesium hydride and influences the dehydrogenation of MgH2. Quantitative X - ray diffraction study of ball milled MgH2 + xTiO2 (x = 0.25, 0.33, 0.5 and 1) suggests that Ti substituted MgO is the main reaction product in all the product powders. Convincing evidence is obtained to conclude that Ti dissolution in MgO makes a dramatic behavioral change to MgO; passive MgO turns as an active in-built catalyst. The analysis correlating the dehydrogenation kinetics, composition of in-situ catalyst and sample durability suggests that effectiveness of Ti substituted MgO (MgxTiyOx+y) as a catalyst for MgH2 depends on the concentration of Ti in MgxTiyOx+y rock salt. These observations are immensely helpful for understanding the hydrogen desorption mechanism of metal oxide additives loaded MgH2 system.

Stabilization of the cubic phase of HfO2 by Y addition in films grown by metal organic chemical vapor deposition

NASA Astrophysics Data System (ADS)

Rauwel, E.; Dubourdieu, C.; Holländer, B.; Rochat, N.; Ducroquet, F.; Rossell, M. D.; Van Tendeloo, G.; Pelissier, B.

2006-07-01

Addition of yttrium in HfO2 thin films prepared on silicon by metal organic chemical vapor deposition is investigated in a wide compositional range (2.0-99.5at.%). The cubic structure of HfO2 is stabilized for 6.5at.%. The permittivity is maximum for yttrium content of 6.5-10at.%; in this range, the effective permittivity, which results from the contribution of both the cubic phase and silicate phase, is of 22. These films exhibit low leakage current density (5×10-7A /cm2 at -1V for a 6.4nm film). The cubic phase is stable upon postdeposition high temperature annealing at 900°C under NH3.

INTEGRATED CHEMICAL INFORMATION TECHNOLOGIES ...

EPA Pesticide Factsheets

A central regulatory mandate of the Environmental Protection Agency, spanning many Program Offices and issues, is to assess the potential health and environmental risks of large numbers of chemicals released into the environment, often in the absence of relevant test data. Models for predicting potential adverse effects of chemicals based primarily on chemical structure play a central role in prioritization and screening strategies yet are highly dependent and conditional upon the data used for developing such models. Hence, limits on data quantity, quality, and availability are considered by many to be the largest hurdles to improving prediction models in diverse areas of toxicology. Generation of new toxicity data for additional chemicals and endpoints, development of new high-throughput, mechanistically relevant bioassays, and increased generation of genomics and proteomics data that can clarify relevant mechanisms will all play important roles in improving future SAR prediction models. The potential for much greater immediate gains, across large domains of chemical and toxicity space, comes from maximizing the ability to mine and model useful information from existing toxicity data, data that represent huge past investment in research and testing expenditures. In addition, the ability to place newer “omics” data, data that potentially span many possible domains of toxicological effects, in the broader context of historical data is the means for opti

Chemical compositions of primitive solar system particles

NASA Technical Reports Server (NTRS)

Sutton, Steve R.; Bajt, S.

1994-01-01

Chemical studies of micrometeorites are of fundamental importance primarily because atmospheric entry selection effects (such as destruction of friable objects) are less significant than those for conventional meteorites. As a result, particles that have experienced very little postaccretional processing have a significant chance of surviving the Earth encounter and subsequent collection. Thus, chemical analyses of these relatively unaltered micrometeorites may lead to a better understanding of the compositions of the most primitive materials in the solar system and thereby constrain the conditions (physical and chemical) that existed in the early solar nebula. Micrometeorites have been collected from the stratosphere, polar ices, and ocean sediments, but the stratospheric collection is the best source for the most unaltered material because they are small and are not heated to their melting points. Despite the fact that the stratospheric micrometeorites have masses in the nanogram range, a variety of microanalytical techniques have been applied to bulk chemical analyses with part-per-million sensitivity. In some cases, multi-disciplinary studies (e.g., chemistry and mineralogy) have been performed on individual particles. The first-order conclusion is that the chondrite-like particles are chemically similar to carbonaceous chondrites but in detail are distinct from members of the conventional meteorite collection. The purpose of this paper is to provide an overview of the results to date and identify important areas for further study.

Chemical Kinetics Database

National Institute of Standards and Technology Data Gateway

SRD 17 NIST Chemical Kinetics Database (Web, free access)   The NIST Chemical Kinetics Database includes essentially all reported kinetics results for thermal gas-phase chemical reactions. The database is designed to be searched for kinetics data based on the specific reactants involved, for reactions resulting in specified products, for all the reactions of a particular species, or for various combinations of these. In addition, the bibliography can be searched by author name or combination of names. The database contains in excess of 38,000 separate reaction records for over 11,700 distinct reactant pairs. These data have been abstracted from over 12,000 papers with literature coverage through early 2000.

Coupled Metagenomic and Chemical Analyses of Degrading Fungal Necromass and Implications for Microbial Contributions to Stable Soil OC

NASA Astrophysics Data System (ADS)

Schreiner, K. M.; Morgan, B. S. T.; Schultz, J.; Blair, N. E.; Egerton-Warburton, L. M.

2014-12-01

Fungi comprise a significant portion of total soil biomass, the turnover of which must represent a dominant flux within the soil carbon cycle. Fungal OC can turn over on time scales of days to months, but this process is poorly understood. Here, we examined temporal changes in the chemical and microbial community composition of fungal necromass during a 2 month decomposition experiment in which Fusarium avenaceum (a common saprophyte) was exposed to a natural soil microbial community. Over the course of the experiment, residual fungal necromass was harvested and analyzed using FTIR and thermochemolysis-GCMS to examine chemical changes in the tissue. Additionally, genomic DNA was extracted from tissues, amplified with barcoded ITS primers, and sequenced using the high-throughput Illumina platform to examine changes in microbial community composition. Up to 80% of the fungal necromass turned over in the first week. This rapid degradation phase corresponded to colonization of the necromass by known chitinolytic soil fungi including Mortierella species. Zygomycetes and Ascomycetes were among the dominant fungal species involved in degradation with very small contributions from Basidiomycetes. At the end of the 2 month degradation, only 15% of the original necromass remained. The residual material was rich in amide and C-O moieties which is consistent with previous work predicting that peptidoglycans are the main residual product from microbial tissue degradation. Straight-chain fatty acids exhibit varying degradation profiles, with some fatty acids (e.g. C16 and C18:1) degrading more rapidly than bulk tissue, others maintaining steady concentrations relative to bulk OC (e.g. C18), and some increasing in concentration throughout the degradation (e.g. C24). These results indicate that the turnover of fungal necromass has the potential to significantly influence a variety of soil OC properties, including C/N ratios, lipid biomarker distributions, and OC turnover times.

Additivity and Interactions in Ecotoxicity of Pollutant Mixtures: Some Patterns, Conclusions, and Open Questions

PubMed Central

Rodea-Palomares, Ismael; González-Pleiter, Miguel; Martín-Betancor, Keila; Rosal, Roberto; Fernández-Piñas, Francisca

2015-01-01

Understanding the effects of exposure to chemical mixtures is a common goal of pharmacology and ecotoxicology. In risk assessment-oriented ecotoxicology, defining the scope of application of additivity models has received utmost attention in the last 20 years, since they potentially allow one to predict the effect of any chemical mixture relying on individual chemical information only. The gold standard for additivity in ecotoxicology has demonstrated to be Loewe additivity which originated the so-called Concentration Addition (CA) additivity model. In pharmacology, the search for interactions or deviations from additivity (synergism and antagonism) has similarly captured the attention of researchers over the last 20 years and has resulted in the definition and application of the Combination Index (CI) Theorem. CI is based on Loewe additivity, but focused on the identification and quantification of synergism and antagonism. Despite additive models demonstrating a surprisingly good predictive power in chemical mixture risk assessment, concerns still exist due to the occurrence of unpredictable synergism or antagonism in certain experimental situations. In the present work, we summarize the parallel history of development of CA, IA, and CI models. We also summarize the applicability of these concepts in ecotoxicology and how their information may be integrated, as well as the possibility of prediction of synergism. Inside the box, the main question remaining is whether it is worthy to consider departures from additivity in mixture risk assessment and how to predict interactions among certain mixture components. Outside the box, the main question is whether the results observed under the experimental constraints imposed by fractional approaches are a de fide reflection of what it would be expected from chemical mixtures in real world circumstances. PMID:29051468

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

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

2012-01-01

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

Nanometer-resolved chemical analyses of femtosecond laser-induced periodic surface structures on titanium

NASA Astrophysics Data System (ADS)

Kirner, Sabrina V.; Wirth, Thomas; Sturm, Heinz; Krüger, Jörg; Bonse, Jörn

2017-09-01

The chemical characteristics of two different types of laser-induced periodic surface structures (LIPSS), so-called high and low spatial frequency LIPSS (HSFL and LSFL), formed upon irradiation of titanium surfaces by multiple femtosecond laser pulses in air (30 fs, 790 nm, 1 kHz), are analyzed by various optical and electron beam based surface analytical techniques, including micro-Raman spectroscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The latter method was employed in a high-resolution mode being capable of spatially resolving even the smallest HSFL structures featuring spatial periods below 100 nm. In combination with an ion sputtering technique, depths-resolved chemical information of superficial oxidation processes was obtained, revealing characteristic differences between the two different types of LIPSS. Our results indicate that a few tens of nanometer shallow HSFL are formed on top of a ˜150 nm thick graded superficial oxide layer without sharp interfaces, consisting of amorphous TiO2 and partially crystallized Ti2O3. The larger LSFL structures with periods close to the irradiation wavelength originate from the laser-interaction with metallic titanium. They are covered by a ˜200 nm thick amorphous oxide layer, which consists mainly of TiO2 (at the surface) and other titanium oxide species of lower oxidation states underneath.

Preface: Chemical Forensics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fraga, Carlos G.

This virtual special issue is devoted to chemical forensics, a developing scientific discipline that aims to provide information to support the attribution of a chemical (or mixture) of interest to its source. This process is carried out through the analysis of the chemical itself or associated material constituents to address investigative, legal or intelligence questions. “Source” refers to how, where and when a chemical was handled or produced. Source information is critical in investigations of incidents of chemicals used for illicit or nefarious purposes, especially when toxic chemicals are used as weapons. The Chemical Weapons Convention (CWC), an international disarmamentmore » treaty that entered into force in 1997, prohibits the use of chemicals as weapons. This treaty has 192 States Parties (the countries who have joined the treaty) encompassing more than 98% of the global population and landmass, yet chemical attacks have continued to increase since this treaty was opened for signature to the governments of the world in 1993. The first notorious use of a chemical weapon since 1993 was by the Aum Shinrikyo cult whose sarin attack on the Tokyo subway system in March 1995 killed 13 and drove another 6,000 to seek medical treatment. More recently, over 160 alleged chemical attacks have been reported in Syria and Iraq with both governments and terrorist groups being accused, and casualties numbering in the thousands. Additionally, recent high profile nerve agent poisoning of dissidents from North Korea and Russia illustrate a willingness to use chemical threat agents (CTAs) with impunity. Given the threat posed by those that choose to use CTAs as weapons, there is a dire need for advancements in chemical forensics that can be used in investigations and inquiries to help find and hold to account, the perpetrators of chemical attacks.« less

Preface: Chemical Forensics

DOE PAGES

Fraga, Carlos G.

2018-04-22

This virtual special issue is devoted to chemical forensics, a developing scientific discipline that aims to provide information to support the attribution of a chemical (or mixture) of interest to its source. This process is carried out through the analysis of the chemical itself or associated material constituents to address investigative, legal or intelligence questions. “Source” refers to how, where and when a chemical was handled or produced. Source information is critical in investigations of incidents of chemicals used for illicit or nefarious purposes, especially when toxic chemicals are used as weapons. The Chemical Weapons Convention (CWC), an international disarmamentmore » treaty that entered into force in 1997, prohibits the use of chemicals as weapons. This treaty has 192 States Parties (the countries who have joined the treaty) encompassing more than 98% of the global population and landmass, yet chemical attacks have continued to increase since this treaty was opened for signature to the governments of the world in 1993. The first notorious use of a chemical weapon since 1993 was by the Aum Shinrikyo cult whose sarin attack on the Tokyo subway system in March 1995 killed 13 and drove another 6,000 to seek medical treatment. More recently, over 160 alleged chemical attacks have been reported in Syria and Iraq with both governments and terrorist groups being accused, and casualties numbering in the thousands. Additionally, recent high profile nerve agent poisoning of dissidents from North Korea and Russia illustrate a willingness to use chemical threat agents (CTAs) with impunity. Given the threat posed by those that choose to use CTAs as weapons, there is a dire need for advancements in chemical forensics that can be used in investigations and inquiries to help find and hold to account, the perpetrators of chemical attacks.« less

Assessment of toxicological profiles of the municipal wastewater effluents using chemical analyses and bioassays.

PubMed

Smital, Tvrtko; Terzic, Senka; Zaja, Roko; Senta, Ivan; Pivcevic, Branka; Popovic, Marta; Mikac, Iva; Tollefsen, Knut Erik; Thomas, Kevin V; Ahel, Marijan

2011-05-01

The hazardous chemical contamination of untreated wastewater and secondary effluent from the wastewater treatment plant (WWTP) of the city of Zagreb, Croatia was comprehensively characterized using large-volume solid-phase extraction (SPE) and silica gel fractionation, followed by a detailed analysis of the resulting extracts by a combination of chemical and bioassay methods. Over 100 individual contaminants or closely related-contaminant groups were identified by high-resolution gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-QTOF). Ecotoxicity profiling of the investigated samples, including cytotoxicity, chronic toxicity and EROD activity; inhibition of the multixenobiotic resistance (MXR), genotoxicity and estrogenic potential, revealed the most significant contribution of toxic compounds to be present in polar fractions. Wastewater treatment using conventional activated sludge process reduced the initial toxicity of raw wastewater to various extents, ranging from 28% for algal toxicity to 73.2% for an estrogenic activity. The most efficient toxicity removal was observed for the polar compounds. Copyright © 2010 Elsevier Inc. All rights reserved.

Constitutive Analyses of Nontraditional Stabilization Additives

DTIC Science & Technology

2004-11-01

cm-I Figure 29. FTIRIATR spectrum of Ven-Set 950 soil stabilization agent Based on the information provided in the MSDS and the FTIR analysis above...emulsion. The MSDS states that it is composed of an acrylic polymer (52 percent) with zinc oxide (2 percent), activated carbon (8 to 9 percent), and...water. The polymer as yet is unidentified. However, it appears to be an acrylate/ methacrylate with some aromaticity (peak about 1,635 c-f’). The

Evaluation of a biocidal turbine-fuel additive.

DOT National Transportation Integrated Search

1967-08-01

Growth of microorganisms in water-contaminated, kerosene-type fuels is a widespread problem in aviation. One approach to the solution of this problem is the introduction into fuel of a chemical additive which could stop or retard growth of microbes. ...

Archive of GHGRP Chemicals Sector Industrial Profile

EPA Pesticide Factsheets

EPA's Greenhouse Gas Reporting Program periodically produces detailed profiles of the various industries that report under the program. The profiles available for download below contain detailed analyses for the Chemicals industry.

Exposure Assessment of Chemicals from Packaging Materials

NASA Astrophysics Data System (ADS)

Poças, Maria De Fátima; Hogg, Timothy

A variety of chemicals may enter our food supply, by means of intentional or unintentional addition, at different stages of the food chain. These chemicals include food additives, pesticide residues, environmental contaminants, mycotox-ins, flavoring substances, and micronutrients. Packaging systems and other food-contact materials are also a source of chemicals contaminating food products and beverages. Monitoring exposure to these chemicals has become an integral part of ensuring the safety of the food supply. Within the context of the risk analysis approach and more specifically as an integral part of risk assessment procedures, the exercise known as exposure assessment is crucial in providing data to allow sound judgments concerning risks to human health. The exercise of obtaining this data is part of the process of revealing sources of contamination and assessing the effectiveness of strategies for minimizing the risk from chemical contamination in the food supply (Lambe, 2002).

Chemical communication threatened by endocrine-disrupting chemicals.

PubMed Central

Fox, Jennifer E

2004-01-01

Communication on a cellular level--defined as chemical signaling, sensing, and response--is an essential and universal component of all living organisms and the framework that unites all ecosystems. Evolutionarily conserved signaling "webs," existing both within an organism and between organisms, rely on efficient and accurate interpretation of chemical signals by receptors. Therefore, endocrine-disrupting chemicals (EDCs), which have been shown to disrupt hormone signaling in laboratory animals and exposed wildlife, may have broader implications for disrupting signaling webs that have yet to be identified as possible targets. In this article, I explore common evolutionary themes of chemical signaling (e.g., estrogen signaling in vertebrates and phytoestrogen signaling from plants to symbiotic soil bacteria) and show that such signaling systems are targets of disruption by EDCs. Recent evolutionary phylogenetic data have shown that the estrogen receptor (ER) is the ancestral receptor from which all other steroid receptors have evolved. In addition to binding endogenous estrogens, ERs also bind phytoestrogens, an ability shared in common with nodulation D protein (NodD) receptors found in Rhizobium soil bacteria. Recent data have shown that many of the same synthetic and natural environmental chemicals that disrupt endocrine signaling in vertebrates also disrupt phytoestrogen-NodD receptor signaling in soil bacteria, which is necessary for nitrogen-fixing symbiosis. Bacteria-plant symbiosis is an unexpected target of EDCs, and other unexpected nontarget species may also be vulnerable to EDCs found in the environment. PMID:15121505

Local chemical potential, local hardness, and dual descriptors in temperature dependent chemical reactivity theory.

PubMed

Franco-Pérez, Marco; Ayers, Paul W; Gázquez, José L; Vela, Alberto

2017-05-31

In this work we establish a new temperature dependent procedure within the grand canonical ensemble, to avoid the Dirac delta function exhibited by some of the second order chemical reactivity descriptors based on density functional theory, at a temperature of 0 K. Through the definition of a local chemical potential designed to integrate to the global temperature dependent electronic chemical potential, the local chemical hardness is expressed in terms of the derivative of this local chemical potential with respect to the average number of electrons. For the three-ground-states ensemble model, this local hardness contains a term that is equal to the one intuitively proposed by Meneses, Tiznado, Contreras and Fuentealba, which integrates to the global hardness given by the difference in the first ionization potential, I, and the electron affinity, A, at any temperature. However, in the present approach one finds an additional temperature-dependent term that introduces changes at the local level and integrates to zero. Additionally, a τ-hard dual descriptor and a τ-soft dual descriptor given in terms of the product of the global hardness and the global softness multiplied by the dual descriptor, respectively, are derived. Since all these reactivity indices are given by expressions composed of terms that correspond to products of the global properties multiplied by the electrophilic or nucleophilic Fukui functions, they may be useful for studying and comparing equivalent sites in different chemical environments.

Use of hydrated lime as an antistripping additive : installation report.

DOT National Transportation Integrated Search

1983-01-01

The purpose of this investigation is to evaluate the effectiveness of hydrated lime as an antistripping additive in several test sections. The two sections installed in 1982 contain S-5 surface mixes with (1) hydrated lime, (2) a chemical additive, a...

Curation of food-relevant chemicals in ToxCast.

PubMed

Karmaus, Agnes L; Trautman, Thomas D; Krishan, Mansi; Filer, Dayne L; Fix, Laurel A

2017-05-01

High-throughput in vitro assays and exposure prediction efforts are paving the way for modeling chemical risk; however, the utility of such extensive datasets can be limited or misleading when annotation fails to capture current chemical usage. To address this data gap and provide context for food-use in the United States (US), manual curation of food-relevant chemicals in ToxCast was conducted. Chemicals were categorized into three food-use categories: (1) direct food additives, (2) indirect food additives, or (3) pesticide residues. Manual curation resulted in 30% of chemicals having new annotation as well as the removal of 319 chemicals, most due to cancellation or only foreign usage. These results highlight that manual curation of chemical use information provided significant insight affecting the overall inventory and chemical categorization. In total, 1211 chemicals were confirmed as current day food-use in the US by manual curation; 1154 of these chemicals were also identified as food-related in the globally sourced chemical use information from Chemical/Product Categories database (CPCat). The refined list of food-use chemicals and the sources highlighted for compiling annotated information required to confirm food-use are valuable resources for providing needed context when evaluating large-scale inventories such as ToxCast. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Evidence for dose-additive effects of pyrethroids on motor activity in rats.

PubMed

Wolansky, Marcelo J; Gennings, Chris; DeVito, Michael J; Crofton, Kevin M

2009-10-01

Pyrethroids are neurotoxic insecticides used in a variety of indoor and outdoor applications. Previous research characterized the acute dose-effect functions for 11 pyrethroids administered orally in corn oil (1 mL/kg) based on assessment of motor activity. We used a mixture of these 11 pyrethroids and the same testing paradigm used in single-compound assays to test the hypothesis that cumulative neurotoxic effects of pyrethroid mixtures can be predicted using the default dose-addition theory. Mixing ratios of the 11 pyrethroids in the tested mixture were based on the ED30 (effective dose that produces a 30% decrease in response) of the individual chemical (i.e., the mixture comprised equipotent amounts of each pyrethroid). The highest concentration of each individual chemical in the mixture was less than the threshold for inducing behavioral effects. Adult male rats received acute oral exposure to corn oil (control) or dilutions of the stock mixture solution. The mixture of 11 pyrethroids was administered either simultaneously (2 hr before testing) or after a sequence based on times of peak effect for the individual chemicals (4, 2, and 1 hr before testing). A threshold additivity model was fit to the single-chemical data to predict the theoretical dose-effect relationship for the mixture under the assumption of dose additivity. When subthreshold doses of individual chemicals were combined in the mixtures, we found significant dose-related decreases in motor activity. Further, we found no departure from the predicted dose-additive curve regardless of the mixture dosing protocol used. In this article we present the first in vivo evidence on pyrethroid cumulative effects supporting the default assumption of dose addition.

9 CFR 318.16 - Pesticide chemicals and other residues in products.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Pesticide chemicals and other residues... PREPARATION OF PRODUCTS General § 318.16 Pesticide chemicals and other residues in products. (a) Nonmeat ingredients. Residues of pesticide chemicals, food additives and color additives or other substances in or on...

9 CFR 318.16 - Pesticide chemicals and other residues in products.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Pesticide chemicals and other residues... PREPARATION OF PRODUCTS General § 318.16 Pesticide chemicals and other residues in products. (a) Nonmeat ingredients. Residues of pesticide chemicals, food additives and color additives or other substances in or on...

9 CFR 318.16 - Pesticide chemicals and other residues in products.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Pesticide chemicals and other residues... PREPARATION OF PRODUCTS General § 318.16 Pesticide chemicals and other residues in products. (a) Nonmeat ingredients. Residues of pesticide chemicals, food additives and color additives or other substances in or on...

9 CFR 318.16 - Pesticide chemicals and other residues in products.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Pesticide chemicals and other residues... PREPARATION OF PRODUCTS General § 318.16 Pesticide chemicals and other residues in products. (a) Nonmeat ingredients. Residues of pesticide chemicals, food additives and color additives or other substances in or on...

Delicious Chemicals.

ERIC Educational Resources Information Center

Barry, Dana M.

This paper presents an approach to chemistry and nutrition that focuses on food items that people consider delicious. Information is organized according to three categories of food chemicals that provide energy to the human body: (1) fats and oils; (2) carbohydrates; and (3) proteins. Minerals, vitamins, and additives are also discussed along with…

Whole-rock analyses of core samples from the 1988 drilling of Kilauea Iki lava lake, Hawaii

USGS Publications Warehouse

Helz, Rosalind Tuthill; Taggart, Joseph E.

2010-01-01

This report presents and evaluates 64 major-element analyses of previously unanalyzed Kilauea Iki drill core, plus three samples from the 1959 and 1960 eruptions of Kilauea, obtained by X-ray fluorescence (XRF) analysis during the period 1992 to 1995. All earlier major-element analyses of Kilauea Iki core, obtained by classical (gravimetric) analysis, were reported and evaluated in Helz and others (1994). In order to assess how well the newer data compare with this earlier suite of analyses, a subset of 24 samples, which had been analyzed by classical analysis, was reanalyzed using the XRF technique; those results are presented and evaluated in this report also. The XRF analyses have not been published previously. This report also provides an overview of how the chemical variations observed in these new data fit in with the chemical zonation patterns and petrologic processes inferred in earlier studies of Kilauea Iki.

Fire-Retardant Polymeric Additives

NASA Technical Reports Server (NTRS)

Williams, Martha K.; Smith, Trent M.

2011-01-01

Polyhydroxyamide (PHA) and polymethoxyamide (PMeOA) are fire-retardant (FR) thermoplastic polymers and have been found to be useful as an additive for imparting fire retardant properties to other compatible, thermoplastic polymers (including some elastomers). Examples of compatible flammable polymers include nylons, polyesters, and acrylics. Unlike most prior additives, PHA and PMeOA do not appreciably degrade the mechanical properties of the matrix polymer; indeed, in some cases, mechanical properties are enhanced. Also, unlike some prior additives, PHA and PMeOA do not decompose into large amounts of corrosive or toxic compounds during combustion and can be processed at elevated temperatures. PMeOA derivative formulations were synthesized and used as an FR additive in the fabrication of polyamide (PA) and polystyrene (PS) composites with notable reduction (>30 percent for PS) in peak heat release rates compared to the neat polymer as measured by a Cone Calorimeter (ASTM E1354). Synergistic effects were noted with nanosilica composites. These nanosilica composites had more than 50-percent reduction in peak heat release rates. In a typical application, a flammable thermoplastic, thermoplastic blend, or elastomer that one seeks to render flame-retardant is first dry-mixed with PHA or PMeOA or derivative thereof. The proportion of PHA or PMeOA or derivative in the mixture is typically chosen to lie between 1 and 20 weight percent. The dry blend can then be melt-extruded. The extruded polymer blend can further be extruded and/or molded into fibers, pipes, or any other of a variety of objects that may be required to be fire-retardant. The physical and chemical mechanisms which impart flame retardancy of the additive include inhibiting free-radical oxidation in the vapor phase, preventing vaporization of fuel (the polymer), and cooling through the formation of chemical bonds in either the vapor or the condensed phase. Under thermal stress, the cyclic hydroxyl/ methoxy

76 FR 3907 - Designation of a Class of Employees for Addition to the Special Exposure Cohort

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-21

... addition to the SEC: All Atomic Weapons Employer employees who worked at Texas City Chemicals, Inc., from... designate a class of employees from Texas City Chemicals, Inc., Texas City, Texas, as an addition to the...

Hazard assessment of hydraulic fracturing chemicals using an indexing method.

PubMed

Hu, Guangji; Liu, Tianyi; Hager, James; Hewage, Kasun; Sadiq, Rehan

2018-04-01

The rapid expansion of unconventional natural gas production has triggered considerable public concerns, particularly regarding environmental and human health (EHH) risks posed by various chemical additives used in hydraulic fracturing (HF) operations. There is a need to assess the potential EHH hazards of additives used in real-world HF operations. In this study, HF additive and fracturing fluid data was acquired, and EHH hazards were assessed using an indexing approach. The indexing system analyzed chemical toxicological data of different ingredients contained within additives and produced an aggregated EHH safety index for each additive, along with an indicator describing the completeness of the chemical toxicological data. The results show that commonly used additives are generally associated with medium-level EHH hazards. In each additive category, ingredients of high EHH concern were identified, and the high hazard designation was primarily attributed to ingredients' high aquatic toxicity and carcinogenic effects. Among all assessed additive categories, iron control agents were identified as the greatest EHH hazards. Lack of information, such as undisclosed ingredients and chemical toxicological data gaps, has resulted in different levels of assessment uncertainties. In particular, friction reducers show the highest data incompleteness with regards to EHH hazards. This study reveals the potential EHH hazards associated with chemicals used in current HF field operations and can provide decision makers with valuable information to facilitate sustainable and responsible unconventional gas production. Copyright © 2017 Elsevier B.V. All rights reserved.

New High Throughput Methods to Estimate Chemical ...

EPA Pesticide Factsheets

EPA has made many recent advances in high throughput bioactivity testing. However, concurrent advances in rapid, quantitative prediction of human and ecological exposures have been lacking, despite the clear importance of both measures for a risk-based approach to prioritizing and screening chemicals. A recent report by the National Research Council of the National Academies, Exposure Science in the 21st Century: A Vision and a Strategy (NRC 2012) laid out a number of applications in chemical evaluation of both toxicity and risk in critical need of quantitative exposure predictions, including screening and prioritization of chemicals for targeted toxicity testing, focused exposure assessments or monitoring studies, and quantification of population vulnerability. Despite these significant needs, for the majority of chemicals (e.g. non-pesticide environmental compounds) there are no or limited estimates of exposure. For example, exposure estimates exist for only 7% of the ToxCast Phase II chemical list. In addition, the data required for generating exposure estimates for large numbers of chemicals is severely lacking (Egeghy et al. 2012). This SAP reviewed the use of EPA's ExpoCast model to rapidly estimate potential chemical exposures for prioritization and screening purposes. The focus was on bounded chemical exposure values for people and the environment for the Endocrine Disruptor Screening Program (EDSP) Universe of Chemicals. In addition to exposure, the SAP

TESTING FOR ADDITIVITY IN THE LOW DOSE REGION OF AN ENVIRONMENTALLY RELEVANT MIXTURE OF 18 OLYHALOGENATED AROMATIC HYDROCARBONS.

EPA Science Inventory

A common default assumption in risk assessment of chemical mixtures is that the chemicals combine additively in the low dose region. Under additivity, with information from single chemical dose-response data, the risk associated with the mixture can be estimated. The objective ...

Oral LD50 toxicity modeling and prediction of per- and polyfluorinated chemicals on rat and mouse.

PubMed

Bhhatarai, Barun; Gramatica, Paola

2011-05-01

Quantitative structure-activity relationship (QSAR) analyses were performed using the LD(50) oral toxicity data of per- and polyfluorinated chemicals (PFCs) on rodents: rat and mouse. PFCs are studied under the EU project CADASTER which uses the available experimental data for prediction and prioritization of toxic chemicals for risk assessment by using the in silico tools. The methodology presented here applies chemometrical analysis on the existing experimental data and predicts the toxicity of new compounds. QSAR analyses were performed on the available 58 mouse and 50 rat LD(50) oral data using multiple linear regression (MLR) based on theoretical molecular descriptors selected by genetic algorithm (GA). Training and prediction sets were prepared a priori from available experimental datasets in terms of structure and response. These sets were used to derive statistically robust and predictive (both internally and externally) models. The structural applicability domain (AD) of the models were verified on 376 per- and polyfluorinated chemicals including those in REACH preregistration list. The rat and mouse endpoints were predicted by each model for the studied compounds, and finally 30 compounds, all perfluorinated, were prioritized as most important for experimental toxicity analysis under the project. In addition, cumulative study on compounds within the AD of all four models, including two earlier published models on LC(50) rodent analysis was studied and the cumulative toxicity trend was observed using principal component analysis (PCA). The similarities and the differences observed in terms of descriptors and chemical/mechanistic meaning encoded by descriptors to prioritize the most toxic compounds are highlighted.

Chemical dispersants enhance the activity of oil- and gas condensate-degrading marine bacteria.

PubMed

Tremblay, Julien; Yergeau, Etienne; Fortin, Nathalie; Cobanli, Susan; Elias, Miria; King, Thomas L; Lee, Kenneth; Greer, Charles W

2017-12-01

Application of chemical dispersants to oil spills in the marine environment is a common practice to disperse oil into the water column and stimulate oil biodegradation by increasing its bioavailability to indigenous bacteria capable of naturally metabolizing hydrocarbons. In the context of a spill event, the biodegradation of crude oil and gas condensate off eastern Canada is an essential component of a response strategy. In laboratory experiments, we simulated conditions similar to an oil spill with and without the addition of chemical dispersant under both winter and summer conditions and evaluated the natural attenuation potential for hydrocarbons in near-surface sea water from the vicinity of crude oil and natural gas production facilities off eastern Canada. Chemical analyses were performed to determine hydrocarbon degradation rates, and metagenome binning combined with metatranscriptomics was used to reconstruct abundant bacterial genomes and estimate their oil degradation gene abundance and activity. Our results show important and rapid structural shifts in microbial populations in all three different oil production sites examined following exposure to oil, oil with dispersant and dispersant alone. We found that the addition of dispersant to crude oil enhanced oil degradation rates and favored the abundance and expression of oil-degrading genes from a Thalassolituus sp. (that is, metagenome bin) that harbors multiple alkane hydroxylase (alkB) gene copies. We propose that this member of the Oceanospirillales group would be an important oil degrader when oil spills are treated with dispersant.

Analysis of entry of additional energy to gunpowder in electrothermal chemical shot

NASA Astrophysics Data System (ADS)

Burkin, Viktor; Ishchenko, Alexandr; Kasimov, Vladimir; Samorokova, Nina; Sidorov, Aleksey

2017-11-01

In the article two series of ballistic experiments conducted according to the scheme of electrothermal chemical control of ballistic parameters of the shot at the Research Institute of Applied Mathematics and Mechanics of Tomsk State University (RIAMM TSU, Russia) are considered. The experimental part of the work is described. The analysis of the electro physical data of ballistic experiments is carried out. A methodical approach that allows to take into account the entry of an electric discharge plasma in a gunpowder in the mathematical model of internal ballistic processes in barrel systems is proposed and tested. Under the conditions of these experiments, the effects of various characteristics of the plasmatron on the nature of the energy entry are estimated.

LOX/GOX sensitivity of fluoroelastomers. [effect of formulation components and addition of fire retardants

NASA Technical Reports Server (NTRS)

Kirshen, N.; Mill, T.

1973-01-01

The effect of formulation components and the addition of fire retardants on the impact sensitivity of Viton B fluoroelastomer in liquid oxygen was studied with the objective of developing a procedure for reliably reducing this sensitivity. Component evaluation, carried out on more than 40 combinations of components and cure cycles, showed that almost all the standard formulation agents, including carbon, MgO, Diak-3, and PbO2, will sensitize the Viton stock either singly or in combinations, some combinations being much more sensitive than others. Cure and postcure treatments usually reduced the sensitivity of a given formulation, often dramatically, but no formulated Viton was as insensitive as the pure Viton B stock. Coating formulated Viton with a thin layer of pure Viton gave some indication of reduced sensitivity, but additional tests are needed. It is concluded that sensitivity in formulated Viton arises from a variety of sources, some physical and some chemical in origin. Elemental analyses for all the formulated Vitons are reported as are the results of a literature search on the subject of LOX impact sensitivity.

Mitigation of Humic Acid Inhibition in Anaerobic Digestion of Cellulose by Addition of Various Salts

PubMed Central

Azman, Samet; Khadem, Ahmad F.; Zeeman, Grietje; van Lier, Jules B.; Plugge, Caroline M.

2015-01-01

Humic compounds are inhibitory to the anaerobic hydrolysis of cellulosic biomass. In this study, the impact of salt addition to mitigate the inhibitory effects of humic compounds was investigated. The experiment was conducted using batch tests to monitor the anaerobic hydrolysis of cellulose in the presence of humic acid. Sodium, potassium, calcium, magnesium and iron salts were tested separately for their efficiency to mitigate humic acid inhibition. All experiments were done under mesophilic conditions (30 °C) and at pH 7. Methane production was monitored online, using the Automatic Methane Potential Test System. Methane production, soluble chemical oxygen demand and volatile fatty acid content of the samples were measured to calculate the hydrolysis efficiencies. Addition of magnesium, calcium and iron salts clearly mitigated the inhibitory effects of humic acid and hydrolysis efficiencies reached up to 75%, 65% and 72%, respectively, which were similar to control experiments. Conversely, potassium and sodium salts addition did not mitigate the inhibition and hydrolysis efficiencies were found to be less than 40%. Mitigation of humic acid inhibition via salt addition was also validated by inductively coupled plasma atomic emission spectroscopy analyses, which showed the binding capacity of different cations to humic acid. PMID:28955013

Analytical methods for the quantification of bisphenol A, alkylphenols, phthalate esters, and perfluoronated chemicals in biological samples.

PubMed

Nakazawa, Hiroyuki; Iwasaki, Yusuke; Ito, Rie

2014-01-01

Our modern society has created a large number of chemicals that are used for the production of everyday commodities including toys, food packaging, cosmetic products, and building materials. We enjoy a comfortable and convenient lifestyle with access to these items. In addition, in specialized areas, such as experimental science and various medical fields, laboratory equipment and devices that are manufactured using a wide range of chemical substances are also extensively employed. The association between human exposure to trace hazardous chemicals and an increased incidence of endocrine disease has been recognized. However, the evaluation of human exposure to such endocrine disrupting chemicals is therefore imperative, and the determination of exposure levels requires the analysis of human biological materials, such as blood and urine. To obtain as much information as possible from limited sample sizes, highly sensitive and reliable analytical methods are also required for exposure assessments. The present review focuses on effective analytical methods for the quantification of bisphenol A (BPA), alkylphenols (APs), phthalate esters (PEs), and perfluoronated chemicals (PFCs), which are chemicals used in the production of everyday commodities. Using data obtained from liquid chromatography/mass spectrometry (LC/MS) and LC/MS/MS analyses, assessments of the risks to humans were also presented based on the estimated levels of exposure to PFCs.

ISS Expeditions 16 through 20: Chemical Analysis Results for Potable Water

NASA Technical Reports Server (NTRS)

Straub, John E., II; Plumlee, Debrah K.; Schultz, John R.

2010-01-01

During the 2-year span from Expedition 16 through Expedition 20, the chemical quality of the potable water onboard the International Space Station (ISS) was verified safe for crew consumption through the return and chemical analysis of archival water samples by the Water and Food Analytical Laboratory (WAFAL) at Johnson Space Center (JSC). Reclaimed cabin humidity condensate and Russian ground-supplied water were the principal sources of potable water for Expeditions 16 through 18. During Expedition 18 the U.S. water processor assembly was delivered, installed, and tested during a 90-day checkout period. Beginning with Expedition 19, U.S. potable water recovered from a combined waste stream of humidity condensate and pretreated urine was also available for ISS crew use. A total of 74 potable water samples were collected using U.S. sampling hardware during Expeditions 16 through 20 and returned on both Shuttle and Soyuz vehicles. The results of JSC chemical analyses of these ISS potable water samples are presented in this paper. Eight potable water samples collected in flight with Russian hardware were also received for analysis, as well as 5 preflight samples of Rodnik potable water delivered to ISS on Russian Progress vehicles 28 to 34. Analytical results for these additional potable water samples are also reported and discussed.

Microbial biosurfactants as additives for food industries.

PubMed

Campos, Jenyffer Medeiros; Stamford, Tânia Lúcia Montenegro; Sarubbo, Leonie Asfora; de Luna, Juliana Moura; Rufino, Raquel Diniz; Banat, Ibrahim M

2013-01-01

Microbial biosurfactants with high ability to reduce surface and interfacial surface tension and conferring important properties such as emulsification, detergency, solubilization, lubrication and phase dispersion have a wide range of potential applications in many industries. Significant interest in these compounds has been demonstrated by environmental, bioremediation, oil, petroleum, food, beverage, cosmetic and pharmaceutical industries attracted by their low toxicity, biodegradability and sustainable production technologies. Despite having significant potentials associated with emulsion formation, stabilization, antiadhesive and antimicrobial activities, significantly less output and applications have been reported in food industry. This has been exacerbated by uneconomical or uncompetitive costing issues for their production when compared to plant or chemical counterparts. In this review, biosurfactants properties, present uses and potential future applications as food additives acting as thickening, emulsifying, dispersing or stabilising agents in addition to the use of sustainable economic processes utilising agro-industrial wastes as alternative substrates for their production are discussed. © 2013 American Institute of Chemical Engineers.

Comparing GWAS Results of Complex Traits Using Full Genetic Model and Additive Models for Revealing Genetic Architecture

PubMed Central

Monir, Md. Mamun; Zhu, Jun

2017-01-01

Most of the genome-wide association studies (GWASs) for human complex diseases have ignored dominance, epistasis and ethnic interactions. We conducted comparative GWASs for total cholesterol using full model and additive models, which illustrate the impacts of the ignoring genetic variants on analysis results and demonstrate how genetic effects of multiple loci could differ across different ethnic groups. There were 15 quantitative trait loci with 13 individual loci and 3 pairs of epistasis loci identified by full model, whereas only 14 loci (9 common loci and 5 different loci) identified by multi-loci additive model. Again, 4 full model detected loci were not detected using multi-loci additive model. PLINK-analysis identified two loci and GCTA-analysis detected only one locus with genome-wide significance. Full model identified three previously reported genes as well as several new genes. Bioinformatics analysis showed some new genes are related with cholesterol related chemicals and/or diseases. Analyses of cholesterol data and simulation studies revealed that the full model performs were better than the additive-model performs in terms of detecting power and unbiased estimations of genetic variants of complex traits. PMID:28079101

NEUROBEHAVIORAL EVALUATIONS OF BINARY AND TERTIARY MIXTURES OF CHEMICALS: LESSIONS LEARNING.

EPA Science Inventory

The classical approach to the statistical analysis of binary chemical mixtures is to construct full dose-response curves for one compound in the presence of a range of doses of the second compound (isobolographic analyses). For interaction studies using more than two chemicals, ...

Chemical decomposition of 5-aza-2'-deoxycytidine (Decitabine): kinetic analyses and identification of products by NMR, HPLC, and mass spectrometry.

PubMed

Rogstad, Daniel K; Herring, Jason L; Theruvathu, Jacob A; Burdzy, Artur; Perry, Christopher C; Neidigh, Jonathan W; Sowers, Lawrence C

2009-06-01

The nucleoside analogue 5-aza-2'-deoxycytidine (Decitabine, DAC) is one of several drugs in clinical use that inhibit DNA methyltransferases, leading to a decrease of 5-methylcytosine in newly replicated DNA and subsequent transcriptional activation of genes silenced by cytosine methylation. In addition to methyltransferase inhibition, DAC has demonstrated toxicity and potential mutagenicity, and can induce a DNA-repair response. The mechanisms accounting for these events are not well understood. DAC is chemically unstable in aqueous solutions, but there is little consensus between previous reports as to its half-life and corresponding products of decomposition at physiological temperature and pH, potentially confounding studies on its mechanism of action and long-term use in humans. Here, we have employed a battery of analytical methods to estimate kinetic rates and to characterize DAC decomposition products under conditions of physiological temperature and pH. Our results indicate that DAC decomposes into a plethora of products, formed by hydrolytic opening and deformylation of the triazine ring, in addition to anomerization and possibly other changes in the sugar ring structure. We also discuss the advantages and problems associated with each analytical method used. The results reported here will facilitate ongoing studies and clinical trials aimed at understanding the mechanisms of action, toxicity, and possible mutagenicity of DAC and related analogues.

Evidence for Dose-Additive Effects of Pyrethroids on Motor Activity in Rats

PubMed Central

Wolansky, Marcelo J.; Gennings, Chris; DeVito, Michael J.; Crofton, Kevin M.

2009-01-01

Background Pyrethroids are neurotoxic insecticides used in a variety of indoor and outdoor applications. Previous research characterized the acute dose–effect functions for 11 pyrethroids administered orally in corn oil (1 mL/kg) based on assessment of motor activity. Objectives We used a mixture of these 11 pyrethroids and the same testing paradigm used in single-compound assays to test the hypothesis that cumulative neurotoxic effects of pyrethroid mixtures can be predicted using the default dose–addition theory. Methods Mixing ratios of the 11 pyrethroids in the tested mixture were based on the ED30 (effective dose that produces a 30% decrease in response) of the individual chemical (i.e., the mixture comprised equipotent amounts of each pyrethroid). The highest concentration of each individual chemical in the mixture was less than the threshold for inducing behavioral effects. Adult male rats received acute oral exposure to corn oil (control) or dilutions of the stock mixture solution. The mixture of 11 pyrethroids was administered either simultaneously (2 hr before testing) or after a sequence based on times of peak effect for the individual chemicals (4, 2, and 1 hr before testing). A threshold additivity model was fit to the single-chemical data to predict the theoretical dose–effect relationship for the mixture under the assumption of dose additivity. Results When subthreshold doses of individual chemicals were combined in the mixtures, we found significant dose-related decreases in motor activity. Further, we found no departure from the predicted dose-additive curve regardless of the mixture dosing protocol used. Conclusion In this article we present the first in vivo evidence on pyrethroid cumulative effects supporting the default assumption of dose addition. PMID:20019907

NMC stratospheric analyses during the 1987 Antarctic expedition

NASA Technical Reports Server (NTRS)

Gelman, Melvyn E.; Newman, Paul A.

1988-01-01

Stratospheric constant pressure analyses of geopotential height and temperature, produced as part of regular operations at the National Meteorological Center (NMC), were used by several participants of the Antarctic Ozone Expedition. A brief decription is given of the NMC stratospheric analyses and the data that are used to derive them. In addition, comparisons of the analysis values at the locations of radiosonde and aircraft data are presented to provide indications for assessing the representativeness of the NMC stratospheric analyses during the 1987 Antarctic winter-spring period.

Characterization of Nano-Hydroxyapatite Synthesized from Sea Shells Through Wet Chemical Method

NASA Astrophysics Data System (ADS)

Santhosh, S.; Prabu, S. Balasivanandha

2012-10-01

Nano-hydroxyapatite (HA) was synthesized by a wet chemical reaction using powdered sea shells (CaO) as starting material which was converted to calcium hydroxide (Ca(OH)2) and subsequently reacted with phosphoric acid (H3PO4). Initially raw sea shells (CaCO3) were thermally converted to amorphous calcium oxide by heat treatment. Two sets of experiments were done; in the first experiment, HA powder was dried in an electric furnace and in the second experiment, the reactants were irradiated in a domestic microwave oven followed by microwave drying. In each set of experiments, the concentrations of the reactants were decreased gradually. HA was synthesized by slow addition of phosphoric acid (H3PO4) in to calcium hydroxide (Ca(OH)2) maintaining the pH of the solution at 10 to avoid the formation of calcium deficient apatites. In both the experiments, Ca:P ratio of 1.67 was maintained for the reagents. The synthesized samples showed X-ray diffraction (XRD) patterns corresponding to hydroxyapatite. The wet chemical process with furnace drying resulted in HA particles of size 7-34 nm, whereas microwave irradiated process yielded HA particles of size 34-102 nm as evidenced from XRD analyses. The above experimental work done by wet chemical synthesis to produce HA powder from sea shells is a simple processing method at room temperature. Microwave irradiation leads to uniform crystallite sizes as evident from this study, at differing concentrations of the reactants and is a comparatively easy method to synthesize HA. The high resolution scanning electron microscopy (HRSEM)/transmission electron microscopic (TEM) analyses revealed the characteristic rod-shaped nanoparticles of HA for the present study.

Coupled Metagenomic and Chemical Analyses of Degrading Fungal Necromass and Implications for Fungal contributions to Stable Soil Organic Carbon

NASA Astrophysics Data System (ADS)

Egerton-Warburton, L. M.; Schreiner, K. M.; Morgan, B. S. T.; Schultz, J.; Blair, N. E.

2016-12-01

Fungi comprise a significant portion of total soil biomass, the turnover of which must represent a dominant flux within the soil carbon cycle. Fungal organic carbon (OC) can turn over on time scales of days to months, but this process is poorly understood. Here, we examined temporal changes in the chemical and microbial community composition of fungal necromass during a 2-month decomposition experiment in which Fusarium avenaceum (a common saprophyte) was exposed to a natural soil microbial community. Over the course of the experiment, residual fungal necromass was harvested and analyzed using FTIR and thermochemolysis-GCMS to examine chemical changes in the tissue. In addition, genomic DNA was extracted from tissues, amplified with barcoded ITS primers, and sequenced using the high-throughput Illumina platform to examine changes in microbial community composition. Up to 80% of the fungal necromass turned over in the first week. This rapid degradation phase corresponded to colonization of the necromass by known chitinolytic soil fungi including Mortierella species. Members of the Zygomycota and Ascomycota were among the dominant fungal groups involved in degradation with very small contributions from Basidiomycota. At the end of the 2-month degradation, only 15% of the original necromass remained. The residual material was rich in amide and C-O moieties which is consistent with previous work predicting that peptidoglycans are the main residual product from microbial tissue degradation. Straight-chain fatty acids exhibited varying degradation profiles, with some fatty acids (e.g. C16, C18:1) degrading more rapidly than bulk tissue while others maintained steady concentrations relative to bulk OC (C18) or increased in concentration throughout the degradation sequence (C24). These results indicate that the turnover of fungal necromass has the potential to rapidly and significantly influence a variety of soil OC properties including C/N ratios, lipid biomarker

Integrated light chemical tagging analyses of seven M31 outer halo globular clusters from the Pan-Andromeda Archaeological Survey

NASA Astrophysics Data System (ADS)

Sakari, Charli M.; Venn, Kim A.; Mackey, Dougal; Shetrone, Matthew D.; Dotter, Aaron; Ferguson, Annette M. N.; Huxor, Avon

2015-04-01

Detailed chemical abundances are presented for seven M31 outer halo globular clusters (with projected distances from M31 greater than 30 kpc), as derived from high-resolution integrated light spectra taken with the Hobby-Eberly Telescope. Five of these clusters were recently discovered in the Pan-Andromeda Archaeological Survey (PAndAS) - this paper presents the first determinations of integrated Fe, Na, Mg, Ca, Ti, Ni, Ba, and Eu abundances for these clusters. Four of the target clusters (PA06, PA53, PA54, and PA56) are metal poor ([Fe/H] < -1.5), α-enhanced (though they are possibly less α-enhanced than Milky Way stars at the 1σ level), and show signs of star-to-star Na and Mg variations. The other three globular clusters (H10, H23, and PA17) are more metal rich, with metallicities ranging from [Fe/H] = -1.4 to -0.9. While H23 is chemically similar to Milky Way field stars, Milky Way globular clusters, and other M31 clusters, H10 and PA17, have moderately low [Ca/Fe], compared to Milky Way field stars and clusters. Additionally, PA17's high [Mg/Ca] and [Ba/Eu] ratios are distinct from Milky Way stars, and are in better agreement with the stars and clusters in the Large Magellanic Cloud. None of the clusters studied here can be conclusively linked to any of the identified streams from PAndAS; however, based on their locations, kinematics, metallicities, and detailed abundances, the most metal-rich PAndAS clusters H23 and PA17 may be associated with the progenitor of the Giant Stellar Stream, H10 may be associated with the SW cloud, and PA53 and PA56 may be associated with the eastern cloud.

The use of hydrated lime as an antistripping additive : final report.

DOT National Transportation Integrated Search

1987-01-01

The purpose of this investigation was to evaluate the performance of six test sections of asphalt concrete that contained no additive, hydrated lime, and a chemical additive. Tests were also conducted on pavement samples taken periodically to determi...

Occurrence and effects of plastic additives on marine environments and organisms: A review.

PubMed

Hermabessiere, Ludovic; Dehaut, Alexandre; Paul-Pont, Ika; Lacroix, Camille; Jezequel, Ronan; Soudant, Philippe; Duflos, Guillaume

2017-09-01

Plastics debris, especially microplastics, have been found worldwide in all marine compartments. Much research has been carried out on adsorbed pollutants on plastic pieces and hydrophobic organic compounds (HOC) associated with microplastics. However, only a few studies have focused on plastic additives. These chemicals are incorporated into plastics from which they can leach out as most of them are not chemically bound. As a consequence of plastic accumulation and fragmentation in oceans, plastic additives could represent an increasing ecotoxicological risk for marine organisms. The present work reviewed the main class of plastic additives identified in the literature, their occurrence in the marine environment, as well as their effects on and transfers to marine organisms. This work identified polybrominated diphenyl ethers (PBDE), phthalates, nonylphenols (NP), bisphenol A (BPA) and antioxidants as the most common plastic additives found in marine environments. Moreover, transfer of these plastic additives to marine organisms has been demonstrated both in laboratory and field studies. Upcoming research focusing on the toxicity of microplastics should include these plastic additives as potential hazards for marine organisms, and a greater focus on the transport and fate of plastic additives is now required considering that these chemicals may easily leach out from plastics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Technical guide for applications of gene expression profiling in human health risk assessment of environmental chemicals.

PubMed

Bourdon-Lacombe, Julie A; Moffat, Ivy D; Deveau, Michelle; Husain, Mainul; Auerbach, Scott; Krewski, Daniel; Thomas, Russell S; Bushel, Pierre R; Williams, Andrew; Yauk, Carole L

2015-07-01

Toxicogenomics promises to be an important part of future human health risk assessment of environmental chemicals. The application of gene expression profiles (e.g., for hazard identification, chemical prioritization, chemical grouping, mode of action discovery, and quantitative analysis of response) is growing in the literature, but their use in formal risk assessment by regulatory agencies is relatively infrequent. Although additional validations for specific applications are required, gene expression data can be of immediate use for increasing confidence in chemical evaluations. We believe that a primary reason for the current lack of integration is the limited practical guidance available for risk assessment specialists with limited experience in genomics. The present manuscript provides basic information on gene expression profiling, along with guidance on evaluating the quality of genomic experiments and data, and interpretation of results presented in the form of heat maps, pathway analyses and other common approaches. Moreover, potential ways to integrate information from gene expression experiments into current risk assessment are presented using published studies as examples. The primary objective of this work is to facilitate integration of gene expression data into human health risk assessments of environmental chemicals. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

An Ice Core Melter System for Continuous Major and Trace Chemical Analyses of a New Mt. Logan Summit Ice Core

NASA Astrophysics Data System (ADS)

Osterberg, E. C.; Handley, M. J.; Sneed, S. D.; Mayewski, P. A.; Kreutz, K. J.; Fisher, D. A.

2004-12-01

The ice core melter system at the University of Maine Climate Change Institute has been recently modified and updated to allow high-resolution (<1-2 cm ice/sample), continuous and coregistered sampling of ice cores, most notably the 2001 Mt. Logan summit ice core (187 m to bedrock), for analyses of 34 trace elements (Sr, Cd, Sb, Cs, Ba, Pb, Bi, U, As, Al, S, Ca, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, REE suite) by inductively coupled plasma mass spectrometry (ICP-MS), 8 major ions (Na+, Ca2+, Mg2+, K+, Cl-, SO42-, NO3-, MSA) by ion chromatography (IC), stable water isotopes (δ 18O, δ D, d) and volcanic tephra. The UMaine continuous melter (UMCoM) system is housed in a dedicated clean room with HEPA filtered air. Standard clean room procedures are employed during melting. A Wagenbach-style continuous melter system has been modified to include a pure Nickel melthead that can be easily dismantled for thorough cleaning. The system allows melting of both ice and firn without wicking of the meltwater into unmelted core. Contrary to ice core melter systems in which the meltwater is directly channeled to online instruments for continuous flow analyses, the UMCoM system collects discrete samples for each chemical analysis under ultraclean conditions. Meltwater from the pristine innermost section of the ice core is split between one fraction collector that accumulates ICP-MS samples in acid pre-cleaned polypropylene vials under a class-100 HEPA clean bench, and a second fraction collector that accumulates IC samples. A third fraction collector accumulates isotope and tephra samples from the potentially contaminated outer portion of the core. This method is advantageous because an archive of each sample remains for subsequent analyses (including trace element isotope ratios), and ICP-MS analytes are scanned for longer intervals and in replicate. Method detection limits, calculated from de-ionized water blanks passed through the entire UMCoM system, are below 10% of average Mt

Chemical markers for bacteria in extraterrestrial samples.

PubMed

Fox, Alvin

2002-11-01

Interplanetary missions to collect pristine Martian surface samples for analysis of organic molecules, and to search for evidence of life, are in the planning phases. The only extraterrestrial samples currently on Earth are lunar dust and rocks, brought back by the Apollo (U.S.) and Luna (Soviet Union) missions to the moon, and meteorites. Meteorites are contaminated when they pass through the Earth's atmosphere, and during environmental exposure on Earth. Lunar fines have been stored on Earth for over 30 years under conditions designed to avoid chemical but not microbiological contamination. It has been extremely difficult to draw firm conclusions about the origin of chemicals (including amino acids) in extraterrestrial samples. Of particular concern has been the possibility of bacterial contamination. Recent work using state-of-the-art gas chromatography tandem mass spectrometry (GC-MS/MS) has dramatically lowered the chemical background, allowing a clear demonstration that lunar fines are remarkably different from terrestrial dust in that they generally lack certain chemical markers (muramic acid and 3-hydroxy fatty acids) characteristic of Earth's bacteria. Thus, lunar dust might be used as a negative control, in conjunction with GC-MS/MS analyses, in future analytical studies of lunar dust and meteorites. Such analyses may also be important in studies designed to search for the presence of life on Mars. Copyright 2002 Wiley-Liss, Inc.

Fourier Transform Mass Spectrometry: The Transformation of Modern Environmental Analyses

PubMed Central

Lim, Lucy; Yan, Fangzhi; Bach, Stephen; Pihakari, Katianna; Klein, David

2016-01-01

Unknown compounds in environmental samples are difficult to identify using standard mass spectrometric methods. Fourier transform mass spectrometry (FTMS) has revolutionized how environmental analyses are performed. With its unsurpassed mass accuracy, high resolution and sensitivity, researchers now have a tool for difficult and complex environmental analyses. Two features of FTMS are responsible for changing the face of how complex analyses are accomplished. First is the ability to quickly and with high mass accuracy determine the presence of unknown chemical residues in samples. For years, the field has been limited by mass spectrometric methods that were based on knowing what compounds of interest were. Secondly, by utilizing the high resolution capabilities coupled with the low detection limits of FTMS, analysts also could dilute the sample sufficiently to minimize the ionization changes from varied matrices. PMID:26784175

Shielding Analyses for VISION Beam Line at SNS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popova, Irina; Gallmeier, Franz X

2014-01-01

Full-scale neutron and gamma transport analyses were performed to design shielding around the VISION beam line, instrument shielding enclosure, beam stop, secondary shutter including a temporary beam stop for the still closed neighboring beam line to meet requirement is to achieve dose rates below 0.25 mrem/h at 30 cm from the shielding surface. The beam stop and the temporary beam stop analyses were performed with the discrete ordinate code DORT additionally to Monte Carlo analyses with the MCNPX code. Comparison of the results is presented.

Logical positivism as a tool to analyse the problem of chemistry's lack of relevance in secondary school chemical education

NASA Astrophysics Data System (ADS)

van Aalsvoort, Joke

2004-09-01

Secondary school chemical education has a problem: namely, the seeming irrelevance to the pupils of chemistry. Chemical education prepares pupils for participation in society. Therefore, it must imply a model of society, of chemistry, and of the relation between them. In this article it is hypothesized that logical positivism currently offers this model. Logical positivism is a philosophy of science that creates a divide between science and society. It is therefore further hypothesized that the adoption of logical positivism causes chemistry's lack of relevance in chemical education. Both hypotheses could be confirmed by an analysis of a grade nine course.

Metagenomic analyses of the late Pleistocene permafrost - additional tools for reconstruction of environmental conditions

NASA Astrophysics Data System (ADS)

Rivkina, Elizaveta; Petrovskaya, Lada; Vishnivetskaya, Tatiana; Krivushin, Kirill; Shmakova, Lyubov; Tutukina, Maria; Meyers, Arthur; Kondrashov, Fyodor

2016-04-01

A comparative analysis of the metagenomes from two 30 000-year-old permafrost samples, one of lake-alluvial origin and the other from late Pleistocene Ice Complex sediments, revealed significant differences within microbial communities. The late Pleistocene Ice Complex sediments (which have been characterized by the absence of methane with lower values of redox potential and Fe2+ content) showed a low abundance of methanogenic archaea and enzymes from both the carbon and nitrogen cycles, but a higher abundance of enzymes associated with the sulfur cycle. The metagenomic and geochemical analyses described in the paper provide evidence that the formation of the sampled late Pleistocene Ice Complex sediments likely took place under much more aerobic conditions than lake-alluvial sediments.

Base Oil-Extreme Pressure Additive Synergy in Lubricants

USDA-ARS?s Scientific Manuscript database

Extreme pressure (EP) additives are those containing reactive elements such as sulfur, phosphorus, and chlorine. In lubrication processes that occur under extremely severe conditions (e.g., high pressure and/or slow speed), these elements undergo chemical reactions generating new materials (tribofi...

Treatment Process Requirements for Waters Containing Hydraulic Fracturing Chemicals

NASA Astrophysics Data System (ADS)

Stringfellow, W. T.; Camarillo, M. K.; Domen, J. K.; Sandelin, W.; Varadharajan, C.; Cooley, H.; Jordan, P. D.; Heberger, M. G.; Reagan, M. T.; Houseworth, J. E.; Birkholzer, J. T.

2015-12-01

A wide variety of chemical additives are used as part of the hydraulic fracturing (HyF) process. There is concern that HyF chemicals will be released into the environment and contaminate drinking water, agricultural water, or other water used for beneficial purposes. There is also interest in using produced water (water extracted from the subsurface during oil and gas production) for irrigation and other beneficial purposes, especially in the arid Southwest US. Reuse of produced water is not speculative: produced water can be low in salts and is being used in California for irrigation after minimal treatment. In this study, we identified chemicals that are used for hydraulic fracturing in California and conducted an analysis to determine if those chemicals would be removed by a variety of technically available treatment processes, including oil/water separation, air stripping, a variety of sorption media, advanced oxidation, biological treatment, and a variety of membrane treatment systems. The approach taken was to establish major physiochemical properties for individual chemicals (log Koc, Henry's constant, biodegradability, etc.), group chemicals by function (e.g corrosion inhibition, biocides), and use those properties to predict the fate of chemical additives in a treatment process. Results from this analysis is interpreted in the context of what is known about existing systems for the treatment of produced water before beneficial reuse, which includes a range of treatment systems from oil/water separators (the most common treatment) to sophisticated treatment trains used for purifying produced water for groundwater recharge. The results show that most HyF chemical additives will not be removed in existing treatment systems, but that more sophisticated treatment trains can be designed to remove additives before beneficial reuse.

ISS Expeditions 16 & 17: Chemical Analysis Results for Potable Water

NASA Technical Reports Server (NTRS)

Straub, John E., II; Plumlee, Debrah K.; Schultz, John R.

2009-01-01

During the twelve month span of Expeditions 16 and 17 beginning October of 2007, the chemical quality of the potable water onboard the International Space Station (ISS) was verified safe for crew consumption through the return and chemical analysis of water samples by the Water and Food Analytical Laboratory (WAFAL) at Johnson Space Center (JSC). Reclaimed cabin humidity condensate and Russian ground-supplied water were the principle sources of potable water and for the first time, European groundsupplied water was also available. Although water was transferred from Shuttle to ISS during Expeditions 16 and 17, no Shuttle potable water was consumed during this timeframe. A total of 12 potable water samples were collected using U.S. hardware during Expeditions 16 and 17 and returned on Shuttle flights 1E (STS122), 1JA (STS123), and 1J (STS124). The average sample volume was sufficient for complete chemical characterization to be performed. The results of JSC chemical analyses of these potable water samples are presented in this paper. The WAFAL also received potable water samples for analysis from the Russian side collected inflight with Russian hardware, as well as preflight samples of Rodnik potable water delivered to ISS on Russian Progress vehicles 28 to 30. Analytical results for these additional potable water samples are also reported and discussed herein. Although the potable water supplies available during Expeditions 16 and 17 were judged safe for crew consumption, a recent trending of elevated silver levels in the SVOZV water is a concern for longterm consumption and efforts are being made to lower these levels.

Non-allergic cutaneous reactions in airborne chemical sensitivity--a population based study.

PubMed

Berg, Nikolaj Drimer; Linneberg, Allan; Thyssen, Jacob Pontoppidan; Dirksen, Asger; Elberling, Jesper

2011-06-01

Multiple chemical sensitivity (MCS) is characterised by adverse effects due to exposure to low levels of chemical substances. The aetiology is unknown, but chemical related respiratory symptoms have been found associated with positive patch test. The purpose of this study was to investigate the relationship between cutaneous reactions from patch testing and self-reported severity of chemical sensitivity to common airborne chemicals. A total of 3460 individuals participating in a general health examination, Health 2006, were patch tested with allergens from the European standard series and screened for chemical sensitivity with a standardised questionnaire dividing the participants into four severity groups of chemical sensitivity. Both allergic and non-allergic cutaneous reactions--defined as irritative, follicular, or doubtful allergic reactions--were analysed in relationship with severity of chemical sensitivity. Associations were controlled for the possible confounding effects of sex, age, asthma, eczema, atopic dermatitis, psychological and social factors, and smoking habits. In unadjusted analyses we found associations between allergic and non-allergic cutaneous reactions on patch testing and the two most severe groups of self-reported sensitivity to airborne chemicals. When adjusting for confounding, associations were weakened, and only non-allergic cutaneous reactions were significantly associated with individuals most severely affected by inhalation of airborne chemicals (odds ratio = 2.5, p = 0.006). Our results suggest that individuals with self-reported chemical sensitivity show increased non-allergic cutaneous reactions based on day 2 readings of patch tests. Copyright © 2011 Elsevier GmbH. All rights reserved.

Chemical Degradation of Polyacrylamide during Hydraulic Fracturing

NASA Astrophysics Data System (ADS)

Xiong, B.; Tasker, T.; Miller, Z.; Roman-White, S.; Farina, B.; Piechowicz, B.; Burgos, W.; Joshi, P.; Zhu, L.; Gorski, C.; Zydney, A.; Kumar, M.

2017-12-01

Polyacrylamide (PAM) based friction reducers are a primary ingredient of slickwater hydraulic fracturing fluids. Little is known regarding the fate of these polymers under downhole conditions, which could have important environmental impacts including strategies for reuse or treatment of flowback water. The objective of this study was to evaluate the chemical degradation of high molecular weight PAM, including the effects of shale, oxygen, temperature, pressure, and salinity. Data were obtained with a slickwater fracturing fluid exposed to both a shale sample collected from a Marcellus shale outcrop and to Marcellus core samples at high pressures/temperatures (HPT) simulating downhole conditions. Based on size exclusion chromatography analyses, the peak molecular weight of the PAM was reduced by two orders of magnitude, from roughly 10 MDa to 200 kDa under typical HPT fracturing conditions. The rate of degradation was independent of pressure and salinity but increased significantly at high temperatures and in the presence of oxygen dissolved in fracturing fluid. Results were consistent with a free radical chain scission mechanism, supported by measurements of sub-M hydroxyl radical concentrations. The shale sample adsorbed some PAM ( 30%), but importantly it catalyzed the chemical degradation of PAM, likely due to dissolution of Fe2+ at low pH. These results provide the first evidence of radical-induced degradation of PAM under HPT hydraulic fracturing conditions without additional oxidative breaker.

Chemical Degradation of Polyacrylamide during Hydraulic Fracturing.

PubMed

Xiong, Boya; Miller, Zachary; Roman-White, Selina; Tasker, Travis; Farina, Benjamin; Piechowicz, Bethany; Burgos, William D; Joshi, Prachi; Zhu, Liang; Gorski, Christopher A; Zydney, Andrew L; Kumar, Manish

2018-01-02

Polyacrylamide (PAM) based friction reducers are a primary ingredient of slickwater hydraulic fracturing fluids. Little is known regarding the fate of these polymers under downhole conditions, which could have important environmental impacts including decisions on strategies for reuse or treatment of flowback water. The objective of this study was to evaluate the chemical degradation of high molecular weight PAM, including the effects of shale, oxygen, temperature, pressure, and salinity. Data were obtained with a slickwater fracturing fluid exposed to both a shale sample collected from a Marcellus outcrop and to Marcellus core samples at high pressures/temperatures (HPT) simulating downhole conditions. Based on size exclusion chromatography analyses, the peak molecular weight of the PAM was reduced by 2 orders of magnitude, from roughly 10 MDa to 200 kDa under typical HPT fracturing conditions. The rate of degradation was independent of pressure and salinity but increased significantly at high temperatures and in the presence of oxygen dissolved in fracturing fluids. Results were consistent with a free radical chain scission mechanism, supported by measurements of sub-μM hydroxyl radical concentrations. The shale sample adsorbed some PAM (∼30%), but importantly it catalyzed the chemical degradation of PAM, likely due to dissolution of Fe 2+ at low pH. These results provide the first evidence of radical-induced degradation of PAM under HPT hydraulic fracturing conditions without additional oxidative breaker.

Occurrence of endocrine-disrupting chemicals in indoor dust

PubMed Central

Hwang, Hyun-Min; Park, Eun-Kee; Young, Thomas M.; Hammock, Bruce D.

2010-01-01

Human exposure to indoor dust enriched with endocrine-disrupting chemicals released from numerous indoor sources has been a focus of increasing concern. Longer residence times and elevated contaminant concentrations in the indoor environment may increase chances of exposure to these contaminants by 1000-fold compared to outdoor exposure. To investigate the occurrence of semi-volatile endocrine-disrupting chemicals, including PBDEs (polybrominated diphenyl ethers), PCBs (polychlorinated biphenyls), phthalates, pyrethroids, DDT (dichlorodiphenyltrichloroethane) and its metabolites, and chlordanes, indoor dust samples were collected from household vacuum cleaner bags provided by 10 apartments and 1 community hall in Davis, California, USA. Chemical analyses show that all indoor dust samples are highly contaminated by target analytes measured in the present study. Di-(2-ethylhexyl)phthalate was the most abundant (104–7630 μg/g) in all samples and higher than other target analytes by 2 to 6 orders of magnitude. PBDEs were also found at high concentrations (1780–25,200 ng/g). Although the use of PCBs has been banned or restricted for decades, some samples had PCBs at levels that are considered to be concerns for human health, indicating that the potential risk posed by PCBs still remains high in the indoor environment, probably due to a lack of dissipation processes and continuous release from the sources. Although the use of some PBDEs is being phased out in some parts of the U.S., this trend may apply to PBDEs as well. We can anticipate that exposure to PBDEs will continue as long as the general public keeps using existing household items such as sofas, mattresses, and carpets that contain PBDEs. This study provides additional information that indoor dust is highly contaminated by persistent and endocrine-disrupting chemicals. PMID:18632138

Toxics Release Inventory Chemical Hazard Information Profiles (TRI-CHIP) Dataset

EPA Pesticide Factsheets

The Toxics Release Inventory (TRI) Chemical Hazard Information Profiles (TRI-CHIP) dataset contains hazard information about the chemicals reported in TRI. Users can use this XML-format dataset to create their own databases and hazard analyses of TRI chemicals. The hazard information is compiled from a series of authoritative sources including the Integrated Risk Information System (IRIS). The dataset is provided as a downloadable .zip file that when extracted provides XML files and schemas for the hazard information tables.

Cumulative effects of antiandrogenic chemical mixtures and their relevance to human health risk assessment.

PubMed

Howdeshell, Kembra L; Hotchkiss, Andrew K; Gray, L Earl

2017-03-01

Toxicological studies of defined chemical mixtures assist human health risk assessment by establishing how chemicals interact with one another to induce an effect. This paper reviews how antiandrogenic chemical mixtures can alter reproductive tract development in rats with a focus on the reproductive toxicant phthalates. The reviewed studies compare observed mixture data to mathematical mixture model predictions based on dose addition or response addition to determine how the individual chemicals in a mixture interact (e.g., additive, greater, or less than additive). Phthalate mixtures were observed to act in a dose additive manner based on the relative potency of the individual phthalates to suppress fetal testosterone production. Similar dose additive effects have been reported for mixtures of phthalates with antiandrogenic pesticides of differing mechanisms of action. Overall, data from these phthalate experiments in rats can be used in conjunction with human biomonitoring data to determine individual hazard indices, and recent cumulative risk assessments in humans indicate an excess risk to antiandrogenic chemical mixtures that include phthalates only or phthalates in combination with other antiandrogenic chemicals. Published by Elsevier GmbH.

Recent meta-analyses neglect previous systematic reviews and meta-analyses about the same topic: a systematic examination.

PubMed

Helfer, Bartosz; Prosser, Aaron; Samara, Myrto T; Geddes, John R; Cipriani, Andrea; Davis, John M; Mavridis, Dimitris; Salanti, Georgia; Leucht, Stefan

2015-04-14

As the number of systematic reviews is growing rapidly, we systematically investigate whether meta-analyses published in leading medical journals present an outline of available evidence by referring to previous meta-analyses and systematic reviews. We searched PubMed for recent meta-analyses of pharmacological treatments published in high impact factor journals. Previous systematic reviews and meta-analyses were identified with electronic searches of keywords and by searching reference sections. We analyzed the number of meta-analyses and systematic reviews that were cited, described and discussed in each recent meta-analysis. Moreover, we investigated publication characteristics that potentially influence the referencing practices. We identified 52 recent meta-analyses and 242 previous meta-analyses on the same topics. Of these, 66% of identified previous meta-analyses were cited, 36% described, and only 20% discussed by recent meta-analyses. The probability of citing a previous meta-analysis was positively associated with its publication in a journal with a higher impact factor (odds ratio, 1.49; 95% confidence interval, 1.06 to 2.10) and more recent publication year (odds ratio, 1.19; 95% confidence interval 1.03 to 1.37). Additionally, the probability of a previous study being described by the recent meta-analysis was inversely associated with the concordance of results (odds ratio, 0.38; 95% confidence interval, 0.17 to 0.88), and the probability of being discussed was increased for previous studies that employed meta-analytic methods (odds ratio, 32.36; 95% confidence interval, 2.00 to 522.85). Meta-analyses on pharmacological treatments do not consistently refer to and discuss findings of previous meta-analyses on the same topic. Such neglect can lead to research waste and be confusing for readers. Journals should make the discussion of related meta-analyses mandatory.

Analyses of soft tissue from Tyrannosaurus rex suggest the presence of protein.

PubMed

Schweitzer, Mary Higby; Suo, Zhiyong; Avci, Recep; Asara, John M; Allen, Mark A; Arce, Fernando Teran; Horner, John R

2007-04-13

We performed multiple analyses of Tyrannosaurus rex (specimen MOR 1125) fibrous cortical and medullary tissues remaining after demineralization. The results indicate that collagen I, the main organic component of bone, has been preserved in low concentrations in these tissues. The findings were independently confirmed by mass spectrometry. We propose a possible chemical pathway that may contribute to this preservation. The presence of endogenous protein in dinosaur bone may validate hypotheses about evolutionary relationships, rates, and patterns of molecular change and degradation, as well as the chemical stability of molecules over time.

NMR relaxometry study of plaster mortar with polymer additives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jumate, E.; Manea, D.; Moldovan, D.

2013-11-13

The cement mixed with water forms a plastic paste or slurry which stiffness in time and finally hardens into a resistant stone. The addition of sand aggregates, polymers (Walocel) and/or calcium carbonate will modify dramatically the final mortar mechanic and thermal properties. The hydration processes can be observed using the 1D NMR measurements of transverse T{sub 2} relaxation times distributions analysed by a Laplace inversion algorithm. These distributions were obtained for mortar pasta measured at 2 hours after preparation then at 3, 7 and 28 days after preparation. Multiple components are identified in the T{sub 2} distributions. These can bemore » associated with the proton bounded chemical or physical to the mortar minerals characterized by a short T{sub 2} relaxation time and to water protons in pores with three different pore sizes as observed from SEM images. The evaporation process is faster in the first hours after preparation, while the mortar hydration (bonding of water molecules to mortar minerals) can be still observed after days or months from preparation. Finally, the mechanic resistance was correlated with the transverse T{sub 2} relaxation rates corresponding to the bound water.« less

NMR relaxometry study of plaster mortar with polymer additives

NASA Astrophysics Data System (ADS)

Jumate, E.; Moldovan, D.; Fechete, R.; Manea, D.

2013-11-01

The cement mixed with water forms a plastic paste or slurry which stiffness in time and finally hardens into a resistant stone. The addition of sand aggregates, polymers (Walocel) and/or calcium carbonate will modify dramatically the final mortar mechanic and thermal properties. The hydration processes can be observed using the 1D NMR measurements of transverse T2 relaxation times distributions analysed by a Laplace inversion algorithm. These distributions were obtained for mortar pasta measured at 2 hours after preparation then at 3, 7 and 28 days after preparation. Multiple components are identified in the T2 distributions. These can be associated with the proton bounded chemical or physical to the mortar minerals characterized by a short T2 relaxation time and to water protons in pores with three different pore sizes as observed from SEM images. The evaporation process is faster in the first hours after preparation, while the mortar hydration (bonding of water molecules to mortar minerals) can be still observed after days or months from preparation. Finally, the mechanic resistance was correlated with the transverse T2 relaxation rates corresponding to the bound water.

Correlation analyses of phytochemical composition, chemical, and cellular measures of antioxidant activity of broccoli (Brassica oleracea L. Var. italica).

PubMed

Eberhardt, Marian V; Kobira, Kanta; Keck, Anna-Sigrid; Juvik, John A; Jeffery, Elizabeth H

2005-09-21

Chemical measures of antioxidant activity within the plant, such as the oxygen radical absorbance capacity (ORAC) assay, have been reported for many plant-based foods. However, the extent to which chemical measures relate to cellular measures of oxidative stress is unclear. The natural variation in the phytochemical content of 22 broccoli genotypes was used to determine correlations among chemical composition (carotenoids, tocopherols and polyphenolics), chemical antioxidant activity (ORAC), and measures of cellular antioxidation [prevention of DNA oxidative damage and of oxidation of the biomarker dichlorofluorescein (DCFH) in HepG2 cells] using hydrophilic and lipophilic extracts of broccoli. For lipophilic extracts, ORAC (ORAC-L) correlated with inhibition of cellular oxidation of DCFH (DCFH-L, r = 0.596, p = 0.006). Also, DNA damage in the presence of the lipophilic extract was negatively correlated with both chemical and cellular measures of antioxidant activity as measured by ORAC-L (r = -0.705, p = 0.015) and DCFH-L (r = -0.671, p = 0.048), respectively. However, no correlations were observed for hydrophilic (-H) extracts, except between polyphenol content and ORAC (ORAC-H; r = 0.778, p < 0.001). Inhibition of cellular oxidation by hydrophilic extracts (DCFH-H) and ORAC-H were approximately 8- and 4-fold greater than DCFH-L and ORAC-L, respectively. Whether ORAC-H has more biological relevance than ORAC-L because of its magnitude or whether ORAC-L bears more biological relevance because it relates to cellular estimates of antioxidant activity remains to be determined. Chemical estimates of antioxidant capacity within the plant may not accurately reflect the complex nature of the full antioxidant activity of broccoli extracts within cells.

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

PubMed

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

2014-07-01

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

Quantifying Special Generator Ridership in Transit Analyses

DOT National Transportation Integrated Search

1997-01-01

In major investment analyses and transit corridor studies, the impact of conventions, sporting matches, and other special events on transit ridership is often of interest. In many locations, it is hypothesized that additional ridership to and from su...

Carcinogenic chemicals in food: evaluating the health risk.

PubMed

Abbott, P J

1992-04-01

The presence of a low level of potentially harmful chemicals in food continues to be a concern to many individuals. A major concern is that these chemicals, which can be synthetic or naturally occurring, may be a causative factor in human cancer. Synthetic chemicals in food may be present either as specific additives or as contaminants derived from environmental or agricultural chemicals. Food also contains a variety of naturally occurring chemicals derived from vegetables or other plants. These may in some cases be considered as contaminants, and are occasionally used as specific additives. New chemicals can also be formed during the cooking or preserving processes. The capacity of any of these chemicals to induce cellular damage and mutation is minimized by natural defence systems such as an efficient cellular detoxification system and DNA repair. The factors influencing tumour formation in humans are numerous and interrelated and exposure to minor dietary chemicals needs to be considered in this context. Thus, the results of animal carcinogenicity assays on individual chemicals need to be interpreted with care, taking into account the mechanisms by which mutagenic and other chemicals initiate cancer, as well as the level of human exposure to these chemicals. Further research is necessary to determine the role, if any, of minor dietary components in tumour formation. Meanwhile, there needs to be a more holistic approach to the multitude of factors, including total diet, that may influence human cancer incidence. In this way, the relative risk of dietary chemicals may be given a more meaningful perspective for health professionals and consumers alike.

Advances in Chemical Mixtures Risk Methods

EPA Science Inventory

This presentation is an overview of emerging issues for dose addition in chemical mixtures risk assessment. It is intended to give the participants a perspective of recent developments in methods for dose addition. The workshop abstract is as follows:This problems-based, half-day...

Anti-Vascular Endothelial Growth Factor Comparative Effectiveness Trial for Diabetic Macular Edema: Additional Efficacy Post Hoc Analyses of a Randomized Clinical Trial.

PubMed

Jampol, Lee M; Glassman, Adam R; Bressler, Neil M; Wells, John A; Ayala, Allison R

2016-12-01

Post hoc analyses from the Diabetic Retinopathy Clinical Research Network randomized clinical trial comparing aflibercept, bevacizumab, and ranibizumab for diabetic macular edema (DME) might influence interpretation of study results. To provide additional outcomes comparing 3 anti-vascular endothelial growth factor (VEGF) agents for DME. Post hoc analyses performed from May 3, 2016, to June 21, 2016, of a randomized clinical trial performed from August 22, 2012, to September 23, 2015, of 660 participants comparing 3 anti-VEGF treatments in eyes with center-involved DME causing vision impairment. Randomization to intravitreous aflibercept (2.0 mg), bevacizumab (1.25 mg), or ranibizumab (0.3 mg) administered up to monthly based on a structured retreatment regimen. Focal/grid laser treatment was added after 6 months for the treatment of persistent DME. Change in visual acuity (VA) area under the curve and change in central subfield thickness (CST) within subgroups based on whether an eye received laser treatment for DME during the study. Post hoc analyses were performed for 660 participants (mean [SD] age, 61 [10] years; 47% female, 65% white, 16% black or African American, 16% Hispanic, and 3% other). For eyes with an initial VA of 20/50 or worse, VA improvement was greater with aflibercept than the other agents at 1 year but superior only to bevacizumab at 2 years. Mean (SD) letter change in VA over 2 years (area under curve) was greater with aflibercept (+17.1 [9.7]) than with bevacizumab (+12.1 [9.4]; 95% CI, +1.6 to +7.3; P < .001) or ranibizumab (+13.6 [8.5]; 95% CI, +0.7 to +6.0; P = .009). When VA was 20/50 or worse at baseline, bevacizumab reduced CST less than the other agents at 1 year, but at 2 years the differences had diminished. In subgroups stratified by baseline VA, anti-VEGF agent, and whether focal/grid laser treatment was performed for DME, the only participants to have a substantial reduction in mean CST between 1 and 2 years were those

Logical Positivism as a Tool to Analyse the Problem of Chemistry's Lack of Relevance in Secondary School Chemical Education

ERIC Educational Resources Information Center

Van Aalsvoort, Joke

2004-01-01

Secondary school chemical education has a problem: namely, the seeming irrelevance to the pupils of chemistry. Chemical education prepares pupils for participation in society. Therefore, it must imply a model of society, of chemistry, and of the relation between them. In this article it is hypothesized that logical positivism currently offers this…

Chemical composition of Texas surface waters, 1949

USGS Publications Warehouse

Irelan, Burdge

1950-01-01

This report is the fifth the a series of publications by the Texas Board of Water Engineers giving chemical analyses of the surface waters in the State of Texas. The samples for which data are given were collected between October 1, 1948 and September 30, 1949. During the water year 25 daily sampling stations were maintained by the Geological Survey. Sampled were collected less frequently during the year at many other points. Quality of water records for previous years can be found in the following reports: "Chemical Composition of Texas Surface Waters, 1938-1945," by W. W. Hastings, and J. H. Rowley; "Chemical Composition of Texas Surface Waters, 1946," by W. W. Hastings and B. Irelan; "Chemical Composition of Texas Surface Waters, 1947," by B. Irelan and J. R. Avrett; "Chemical Composition of Texas Surface Waters, 1948," by B. Irelan, D. E. Weaver, and J. R. Avrett. These reports may be obtained from the Texas Board of Water Engineers and Geological Survey at Austin, Texas. Samples for chemical analysis were collected daily at or near points on streams where gaging stations are maintained for measurement of discharge. Most of the analyses were made of 10-day composites of daily samples collected for a year at each sampling point. Three composite samples were usually prepared each month by mixing together equal quantities of daily samples collected for the 1st to the 10th, from the 11th to the 20th, and during the remainder of the month. Monthly composites were made at a few stations where variation in daily conductance was small. For some streams that are subject to sudden large changes in chemical composition, composite samples were made for shorter periods on the basis of the concentration of dissolved solids as indicated by measurement of specific conductance of the daily samples. The mean discharge for the composite period is reported in second-feet. Specific conductance values are expressed as "micromhos, K x 10 at 25° C." Silica, calcium, magnesium, sodium

Manipulating crystallization with molecular additives.

PubMed

Shtukenberg, Alexander G; Lee, Stephanie S; Kahr, Bart; Ward, Michael D

2014-01-01

Given the importance of organic crystals in a wide range of industrial applications, the chemistry, biology, materials science, and chemical engineering communities have focused considerable attention on developing methods to control crystal structure, size, shape, and orientation. Tailored additives have been used to control crystallization to great effect, presumably by selectively binding to particular crystallographic surfaces and sites. However, substantial knowledge gaps still exist in the fundamental mechanisms that govern the formation and growth of organic crystals in both the absence and presence of additives. In this review, we highlight research discoveries that reveal the role of additives, either introduced by design or present adventitiously, on various stages of formation and growth of organic crystals, including nucleation, dislocation spiral growth mechanisms, growth inhibition, and nonclassical crystal morphologies. The insights from these investigations and others of their kind are likely to guide the development of innovative methods to manipulate crystallization for a wide range of materials and applications.

The chemical foundations of nitroalkene fatty acid signaling through addition reactions with thiols.

PubMed

Turell, Lucía; Steglich, Martina; Alvarez, Beatriz

2018-03-22

Nitroalkene fatty acids can be formed in vivo and administered exogenously. They exert pleiotropic signaling actions with cytoprotective and antiinflammatory effects. The presence of the potent electron withdrawing nitro group confers electrophilicity to the adjacent β-carbon. Thiols (precisely, thiolates) are strong nucleophiles and can react with nitroalkene fatty acids through reversible Michael addition reactions. In addition, nitroalkene fatty acids can undergo several other processes including metabolic oxidation, reduction, esterification, nitric oxide release and partition into hydrophobic compartments. The signaling actions of nitroalkenes are mainly mediated by reactions with critical thiols in regulatory proteins. Thus, the thio-Michael addition reaction provides a framework for understanding the molecular basis of the biological effects of nitroalkene fatty acids at the crossroads of thiol signaling and electrophilic lipid signaling. In this review, we describe the reactions of nitroalkene fatty acids in biological contexts. We focus on the Michael addition-elimination reaction with thiols and its mechanism, and extrapolate kinetic and thermodynamic considerations to in vivo settings. Copyright © 2018 Elsevier Inc. All rights reserved.

Lipid Adjustment for Chemical Exposures: Accounting for Concomitant Variables

PubMed Central

Li, Daniel; Longnecker, Matthew P.; Dunson, David B.

2013-01-01

Background Some environmental chemical exposures are lipophilic and need to be adjusted by serum lipid levels before data analyses. There are currently various strategies that attempt to account for this problem, but all have their drawbacks. To address such concerns, we propose a new method that uses Box-Cox transformations and a simple Bayesian hierarchical model to adjust for lipophilic chemical exposures. Methods We compared our Box-Cox method to existing methods. We ran simulation studies in which increasing levels of lipid-adjusted chemical exposure did and did not increase the odds of having a disease, and we looked at both single-exposure and multiple-exposures cases. We also analyzed an epidemiology dataset that examined the effects of various chemical exposures on the risk of birth defects. Results Compared with existing methods, our Box-Cox method produced unbiased estimates, good coverage, similar power, and lower type-I error rates. This was the case in both single- and multiple-exposure simulation studies. Results from analysis of the birth-defect data differed from results using existing methods. Conclusion Our Box-Cox method is a novel and intuitive way to account for the lipophilic nature of certain chemical exposures. It addresses some of the problems with existing methods, is easily extendable to multiple exposures, and can be used in any analyses that involve concomitant variables. PMID:24051893

Phospholipid and Respiratory Quinone Analyses From Extreme Environments

NASA Astrophysics Data System (ADS)

Pfiffner, S. M.

2008-12-01

Extreme environments on Earth have been chosen as surrogate sites to test methods and strategies for the deployment of space craft in the search for extraterrestrial life. Surrogate sites for many of the NASA astrobiology institutes include the South African gold mines, Canadian subpermafrost, Atacama Desert, and acid rock drainage. Soils, sediments, rock cores, fracture waters, biofilms, and service and drill waters represent the types of samples collected from these sites. These samples were analyzed by gas chromatography mass spectrometry for phospholipid fatty acid methyl esters and by high performance liquid chromatography atmospheric pressure chemical ionization tandem mass spectrometry for respiratory quinones. Phospholipid analyses provided estimates of biomass, community composition, and compositional changes related to nutritional limitations or exposure to toxic conditions. Similar to phospholipid analyses, respiratory quinone analyses afforded identification of certain types of microorganisms in the community based on respiration and offered clues to in situ redox conditions. Depending on the number of samples analyzed, selected multivariate statistical methods were applied to relate membrane lipid results with site biogeochemical parameters. Successful detection of life signatures and refinement of methodologies at surrogate sites on Earth will be critical for the recognition of extraterrestrial life. At this time, membrane lipid analyses provide useful information not easily obtained by other molecular techniques.

Development of Brassica oleracea-nigra monosomic alien addition lines: genotypic, cytological and morphological analyses.

PubMed

Tan, Chen; Cui, Cheng; Xiang, Yi; Ge, Xianhong; Li, Zaiyun

2017-12-01

We report the development and characterization of Brassica oleracea - nigra monosomic alien addition lines (MAALs) to dissect the Brassica B genome. Brassica nigra (2n = 16, BB) represents the diploid Brassica B genome which carries many useful genes and traits for breeding but received limited studies. To dissect the B genome from B. nigra, the triploid F 1 hybrid (2n = 26, CCB) obtained previously from the cross B. oleracea var. alboglabra (2n = 18, CC) × B. nigra was used as the maternal parent and backcrossed successively to parental B. oleracea. The progenies in BC 1 to BC 3 generations were analyzed by the methods of FISH and SSR markers to screen the monosomic alien addition lines (MAALs) with each of eight different B-genome chromosomes added to C genome (2n = 19, CC + 1B 1-8 ), and seven different MAALs were established, except for the one with chromosome B2 which existed in one triple addition. Most of these MAALs were distinguishable morphologically from each other, as they expressed the characters from B. nigra differently and at variable extents. The alien chromosome remained unpaired as a univalent in 86.24% pollen mother cells at diakinesis or metaphase I, and formed a trivalent with two C-genome chromosomes in 13.76% cells. Transmission frequency of all the added chromosomes was far higher through the ovules (averagely 14.40%) than the pollen (2.64%). The B1, B4 and B5 chromosomes were transmitted by female at much higher rates (22.38-30.00%) than the other four (B3, B6, B7, B8) (5.04-8.42%). The MAALs should be valuable for exploiting the genome structure and evolution of B. nigra.

40 CFR 230.61 - Chemical, biological, and physical evaluation and testing.

Code of Federal Regulations, 2013 CFR

2013-07-01

... potential effects on the water column and on communities of aquatic organisms. (1) Evaluation of chemical... further analyses and how the results of the analyses will be of value in evaluating potential... sites may aid in making an environmental assessment of the proposed disposal operation. Such differences...

A new grading system for plant-available potassium using exhaustive cropping techniques combined with chemical analyses of soils

PubMed Central

Li, Ting; Wang, Huoyan; Zhou, Zijun; Chen, Xiaoqin; Zhou, Jianmin

2016-01-01

A new grading system for plant-available potassium (K) in soils based on K release rate from soils and plant growth indices was established. In the study, fourteen different agricultural soils from the southern subtropical to the northern temperate zones in China were analyzed by both chemical extraction methods and exhaustive cropping techniques. Based on the change trends in plant growth indices, relative biomass yields of 70% and 50%, K-deficient coefficients of 35 and 22 under conventional exhaustive experiments, and tissue K concentrations of 40 g kg−1 and 15 g kg−1 under intensive exhaustive experiments were obtained as critical values that represent different change trends. In addition, the extraction method using 0.2 mol L−1 sodium tetraphenylboron (NaTPB) suggested soil K release rates of 12 mg kg−1 min−1 and 0.4 mg kg−1 min−1 as turning points that illustrated three different release trends. Thus, plant-available K in soils was classified into three categories: high available K, medium available K and low available K, and grading criteria and measurement methods were also proposed. This work has increased our understanding of soil K bioavailability and has direct application in terms of routine assessment of agriculture soils. PMID:27876838

Neutral insulin solutions physically stabilized by addition of Zn2+.

PubMed

Brange, J; Havelund, S; Hommel, E; Sørensen, E; Kühl, C

1986-01-01

Commercial neutral insulin solutions, all of which contain 2-3 zinc atoms per hexameric unit of insulin, have a relatively limited physical stability when exposed to heat and movement, as for example in insulin infusion pumps. Physical stabilization of neutral insulin solutions has been obtained by addition of two extra Zn2+ per hexamer of insulin. This addition stabilizes porcine and human neutral solutions equally well and does not affect the chemical stability of the insulin. The stabilization is probably obtained by a further strengthening of the hexameric structure of insulin, so that the formation of insoluble insulin fibrils (via the dissociation into the insulin monomer or dimer) is impeded or prevented. The addition of an extra 2 Zn2+ has been shown to be without influence on the insulin immunogenicity in rabbits or on the rate of absorption after subcutaneous injection in diabetic patients. It is concluded that neutral insulin solution can be physically stabilized by addition of extra Zn2+ without affecting other qualities of the insulin preparation including chemical stability, immunogenicity, and duration of action after injection.

Surface molecular imprinting onto fluorescein-coated magnetic nanoparticlesvia reversible addition fragmentation chain transfer polymerization: A facile three-in-one system for recognition and separation of endocrine disrupting chemicals

NASA Astrophysics Data System (ADS)

Li, Ying; Dong, Cunku; Chu, Jia; Qi, Jingyao; Li, Xin

2011-01-01

In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads viareversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms) = 3.67 emu g-1). The hybrids bind the original template 17β-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals.In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads viareversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms) = 3.67 emu g-1). The hybrids bind the original template 17β-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals. Electronic

Entropy Generation in a Chemical Reaction

ERIC Educational Resources Information Center

Miranda, E. N.

2010-01-01

Entropy generation in a chemical reaction is analysed without using the general formalism of non-equilibrium thermodynamics at a level adequate for advanced undergraduates. In a first approach to the problem, the phenomenological kinetic equation of an elementary first-order reaction is used to show that entropy production is always positive. A…

Integrated Light Chemical Abundance Analyses of 7 M31 Outer Halo Globular Clusters from the Pan-Andromeda Archaeological Survey

NASA Astrophysics Data System (ADS)

Sakari, Charli; Venn, Kim; Mackey, Dougal; Shetrone, Matthew D.; Dotter, Aaron L.; Wallerstein, George

2015-01-01

Detailed chemical abundances of globular clusters provide insight into the formation and evolution of galaxies and their globular cluster systems. This talk presents detailed chemical abundances for seven M31 outer halo globular clusters (with projected radii greater than 30 kpc), as derived from high resolution integrated light spectra. Five of these clusters were recently discovered in the Pan-Andromeda Archaeological Survey (PAndAS). The integrated abundances show that 4 of these clusters are metal-poor ([Fe/H] < -1.5) while the other 3 are more metal-rich. The most metal-poor globular clusters are α-enhanced, though 3 of the 4 are possibly less α-enhanced than MW stars (at the 1σ level). Other chemical abundance ratios ([Ba/Eu], [Eu/Ca], and [Ni/Fe]) are consistent with origins in low mass dwarf galaxies (similar to Fornax). The most metal-rich cluster ([Fe/H] ~ -1) stands out as being chemically distinct from Milky Way field stars of the same metallicity---its chemical abundance ratios agree best with the stars and clusters in the Large Magellanic Cloud (LMC) and the Sagittarius dwarf spheroidal (Sgr) than with the Milky Way field stars. The other metal-rich clusters, H10 and H23, look similar to the LMC and Milky Way field stars in all abundance ratios. These results indicate that M31's outer halo is being at least partially built up by the accretion of dwarf satellites, in agreement with previous observations.

Comparison of macronutrient contents in human milk measured using mid-infrared human milk analyser in a field study vs. chemical reference methods.

PubMed

Zhu, Mei; Yang, Zhenyu; Ren, Yiping; Duan, Yifan; Gao, Huiyu; Liu, Biao; Ye, Wenhui; Wang, Jie; Yin, Shian

2017-01-01

Macronutrient contents in human milk are the common basis for estimating these nutrient requirements for both infants and lactating women. A mid-infrared human milk analyser (HMA, Miris, Sweden) was recently developed for determining macronutrient levels. The purpose of the study is to compare the accuracy and precision of HMA method with fresh milk samples in the field studies with chemical methods with frozen samples in the lab. Full breast milk was collected using electric pumps and fresh milk was analyzed in the field studies using HMA. All human milk samples were thawed and analyzed with chemical reference methods in the lab. The protein, fat and total solid levels were significantly correlated between the two methods and the correlation coefficient was 0.88, 0.93 and 0.78, respectively (p  <  0.001). The mean protein content was significantly lower and the mean fat level was significantly greater when measured using HMA method (1.0 g 100 mL -1 vs 1.2 g 100 mL -1 and 3. 7 g 100 mL -1 vs 3.2 g 100 mL -1 , respectively, p  <  0.001). Thus, linear recalibration could be used to improve mean estimation for both protein and fat. There was no significant correlation for lactose between the two methods (p  >  0.05). There was no statistically significant difference in the mean total solid concentration (12.2 g 100 mL -1 vs 12.3 g 100 mL -1 , p  >  0.05). Overall, HMA might be used to analyze macronutrients in fresh human milk with acceptable accuracy and precision after recalibrating fat and protein levels of field samples. © 2016 John Wiley & Sons Ltd.

Quantum chemical calculations of Cr2O3/SnO2 using density functional theory method

NASA Astrophysics Data System (ADS)

Jawaher, K. Rackesh; Indirajith, R.; Krishnan, S.; Robert, R.; Das, S. Jerome

2018-03-01

Quantum chemical calculations have been employed to study the molecular effects produced by Cr2O3/SnO2 optimised structure. The theoretical parameters of the transparent conducting metal oxides were calculated using DFT / B3LYP / LANL2DZ method. The optimised bond parameters such as bond lengths, bond angles and dihedral angles were calculated using the same theory. The non-linear optical property of the title compound was calculated using first-order hyperpolarisability calculation. The calculated HOMO-LUMO analysis explains the charge transfer interaction between the molecule. In addition, MEP and Mulliken atomic charges were also calculated and analysed.

Reduction of nitrate in aquifer microcosms by carbon additions

USGS Publications Warehouse

Obenhuber, Donald C.; Lowrance , Richard

1991-01-01

Aquifer microcosms were used to examine the effects of NO−3 and C amendments on groundwater from the Claiborne aquifer. Nitrate concentrations of 12.17 mg L−1 in aquifer microcosms were reduced 0.92%/d to 5.84 mg L−1 by the addition of 10 mg C L−1 for 35 d. Nitrate disappearance correlated with increases in number of denitrifiers and dissolved N2O concentration and decreases in dissolved oxygen, suggesting biological denitrification. Nitrate/chloride ratios decreased in microcosms with 10 mg C L−1 added and then increased when the C addition was removed. Carbon additions of 0.4 mg C L−1 had no effect on the microbial or chemical properties of the microcosms. Nitrous oxide levels in wells sampling the Claiborne aquifer showed an increase with depth, indicating N2O production within the aquifer. Microcosms are useful tools to examine biological transformations of chemical contaminants in unconsolidated aquifer material. The remediation of NO−3 contaminated aquifers by organic infusion is possible and appears to be a function of microbial denitrification.

Resin additive improves performance of high-temperature hydrocarbon lubricants

NASA Technical Reports Server (NTRS)

Johnson, R. L.; Loomis, W. R.

1971-01-01

Paraffinic resins, in high temperature applications, improve strength of thin lubricant film in Hertzian contacts even though they do not increase bulk oil viscosity. Use of resin circumvents corrosivity and high volatility problems inherent with many chemical additives.

Superhydrophobic powder additives to enhance chemical agent resistant coating systems for military equipment for the U.S. Marine Corps (USMC) Corrosion Prevention and Control (CPAC) Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pawel, Steven J.; Armstrong, Beth L.; Haynes, James A.

The primary goal of the CPAC program at ORNL was to explore the feasibility of introducing various silica-based superhydrophobic (SH) powder additives as a way to improve the corrosion resistance of US Department of Defense (DOD) military-grade chemical agent resistant coating (CARC) systems. ORNL had previously developed and patented several SH technologies of interest to the USMC, and one of the objectives of this program was to identify methods to incorporate these technologies into the USMC’s corrosion-resistance strategy. This report discusses findings of the CPAC and their application.

Effect of Coulomb interaction on chemical potential of metal film

NASA Astrophysics Data System (ADS)

Kostrobij, P. P.; Markovych, B. M.

2018-07-01

The chemical potential of a metal film within the jellium model taking into account the Coulomb interaction between electrons is calculated. The surface potential is modelled as the infinite rectangular potential well. The behaviour of the chemical potential as a function of the film thickness is studied, the quantum size effect for this quantity is analysed. It is shown that taking into account the Coulomb interaction leads to a significant decrease of the chemical potential and to an enhancement of the quantum size effect.

Non-target screening analyses of organic contaminants in river systems as a base for monitoring measures

NASA Astrophysics Data System (ADS)

Schwarzbauer, J.

2009-04-01

Organic contaminants discharged to the aquatic environment exhibit a high diversity with respect to their molecular structures and the resulting physico-chemical properties. The chemical analysis of anthropogenic contamination in river systems is still an important feature, especially with respect to (i) the identification and structure elucidation of novel contaminants, (ii) to the characterisation of their environmental behaviour and (iii) to their risk for natural systems. A huge proportion of riverine contamination is caused by low-molecular weight organic compounds, like pesticides plasticizers, pharmaceuticals, personal care products, technical additives etc. Some of them, like PCB or PAH have already been investigated thoroughly and, consequently, their behaviour in aqueous systems is very well described. Although analyses on organic substances in river water traditionally focused on selected pollutants, in particular on common priority pollutants which are monitored routinely, the occurrence of further contaminants, e.g. pharmaceuticals, personal care products or chelating agents has received increasing attention within the last decade. Accompanied, screening analyses revealing an enormous diversity of low-molecular weight organic contaminants in waste water effluents and river water become more and more noticed. Since many of these substances have been rarely noticed so far, it will be an important task for the future to study their occurrence and fate in natural environments. Further on, it should be a main issue of environmental studies to provide a comprehensive view on the state of pollution of river water, in particular with respect to lipophilic low molecular weight organic contaminants. However, such non-target-screening analyses has been performed only rarely in the past. Hence, we applied extended non-target screening analyses on longitudinal sections of the rivers Rhine, Rur and Lippe (Germany) on the base of GC/MS analyses. The investigations

Synthesis, characterization, cytotoxicity, cell cycle analysis of 3-(4-methoxyphenyl)-1-(pyridin-2-ylmethyl)thiourea and quantum chemical analyses

NASA Astrophysics Data System (ADS)

Mushtaque, Md.; Avecilla, Fernando; Khan, Md. Shahzad; Hafeez, Zubair Bin; Rezvi, M. Moshahid A.; Srivastava, Anurag

2017-08-01

Thiourea derivative,3-(4-methoxyphenyl)-1-(pyridin-2-ylmethyl)thiourea, was synthesized. The structure of the synthesized compound (3) was elucidated by IR, UV-visible, 1H NMR, mass Spectrometry, and X-ray single crystal structure. The computational quantum chemical studies like, IR, UV, NBO analysis were performed by DFT with Becke-3-Lee-Yang- Parr (B3LYP) exchange-correlation functional in combination with 6-311++G(d,p) basis sets. It was observed experimentally and theoretically that compound (3) exhibited syn-anti-conformation around sulphur atom. The DNA-binding constant Kb was found 3.3 × 106 Lmol-1. The docking energy of compound (3) with 1BNA was found -6.2 kcal/mol. MTT-assay against HepG2 (IC50 = 140.39) and Siha (IC50 = 119.87 μM) cell lines revealed that compound (3) wasnon-toxic up to140.39 μM against HepG2 and 119.87 μM against Siha cells respectively. It was also found that compound (3) is non-toxic against normal human cell line HEK-293(IC50 = 148.67 μM). Cell cycle analyses displayed that treated HepG2 cells at 40 μM and 80 μM showed 65% and 70% arrest in G0/G1with respect to untreated controls (60%) and Siha cells at the same concentration displayed 59% and 65% arrest with respect to G0/G1 as compared to untreated control (45%).

Enhanced understanding of the relationship between chemical modification and mechanical properties of wood

Treesearch

Charles R. Frihart; Daniel J. Yelle; John Ralph; Robert J. Moon; Donald S. Stone; Joseph E. Jakes

2008-01-01

Chemical additions to wood often change its bulk properties, which can be determined using conventional macroscopic mechanical tests. However, the controlling interactions between chemicals and wood take place at and below the scale of individual cells and cell walls. To better understand the effects of chemical additions to wood, we have adapted and extended two...

A Comprehensive Review on Chemical Profiling of Nelumbo Nucifera: Potential for Drug Development.

PubMed

Sharma, Bhesh Raj; Gautam, Lekh Nath S; Adhikari, Deepak; Karki, Rajendra

2017-01-01

Nelumbo nucifera, also known as sacred lotus, has primarily been used as food throughout the Asian continent, and its medicinal values have been described in Ayurvedic and Traditional Chinese Medicine. The purpose of this study is to systematically characterize the chemical profiling and pharmacological activities of N. nucifera. Herein, we critically reviewed and analysed the phytochemical and pharmacological reports of N. nucifera. Our search for the keyword 'Nelumbo nucifera pharmacology' in all databases reported in Web of Science yielded 373 results excluding reviews and abstracts in document types. Two hundred and forty-three spectrum natural compounds from different parts of N. nucifera belonging to diverse chemical groups, including alkaloids, flavonoids, glycosides, terpenoids, steroids, fatty acids, proteins, minerals, and vitamins have been reported. In addition, distinct pharmacological activities, mainly against cancer, microbial infection, diabetes, inflammation, atherosclerosis, and obesity, have been associated with crude extracts, fractions, and isolated compounds. This review highlights potential use of neferine, liensinine, isoliensinine, and nuciferine in clinical trials. In depth, mechanism of the potential chemical entities from N. nucifera via structure activity relationship needs to be explored to guarantee the stability and safety for the clinical use. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Characterization of traditional Istrian dry-cured ham by means of physical and chemical analyses and volatile compounds.

PubMed

Marušić, Nives; Petrović, Marinko; Vidaček, Sanja; Petrak, Tomislav; Medić, Helga

2011-08-01

The aroma-active compounds of Istrian dry-cured ham were investigated by using headspace-solid phase microextraction and gas chromatography-mass spectrometry (GC-MS). Samples of biceps femoris were also evaluated by measuring physical and chemical characteristics: moisture, protein, fat, ash and NaCl content, a(w) value; colour: L*, a*, b* and oxidation of fat: TBARS test. About 50 volatile compounds were identified and quantified which belonged to several classes of chemical: 5 alcohols, 8 aldehydes, 7 alkanes, 1 ketone, 2 esters, 9 monoterpenes and 15 sesquiterpenes. Except volatile compounds derived from lipolysis and proteolysis the most abundant constituents were terpenes (62.97; 41.43%) that originate from spices added in the salting phase of the production process. Copyright © 2011 Elsevier Ltd. All rights reserved.

Active mineral additives of sapropel ashes

NASA Astrophysics Data System (ADS)

Khomich, V. A.; Danilina, E. V.; Krivonos, O. I.; Plaksin, G. V.

2015-01-01

The goal of the presented research is to establish a scientific rational for the possibility of sapropel ashes usage as an active mineral additive. The research included the study of producing active mineral additives from sapropels by their thermal treatment at 850900 °C and afterpowdering, the investigation of the properties of paste matrix with an ash additive, and the study of the ash influence on the cement bonding agent. Thermogravimetric analysis and X-ray investigations allowed us to establish that while burning, organic substances are removed, clay minerals are dehydrated and their structure is broken. Sapropel ashes chemical composition was determined. An amorphous ash constituent is mainly formed from silica of the mineral sapropel part and alumosilicagels resulted from clay minerals decomposition. Properties of PC 400 and PC 500A0 sparopel ash additives were studied. Adding ashes containing Glenium plasticizer to the cement increases paste matrix strength and considerably reduces its water absorption. X-ray phase analysis data shows changes in the phase composition of the paste matrix with an ash additive. Ash additives produce a pozzolanic effect on the cement bonding agent. Besides, an ash additive due to the alumosilicagels content causes transformation from unstable calcium aluminate forms to the stable ones.

Identification of candidate reference chemicals for in vitro steroidogenesis assays.

PubMed

Pinto, Caroline Lucia; Markey, Kristan; Dix, David; Browne, Patience

2018-03-01

The Endocrine Disruptor Screening Program (EDSP) is transitioning from traditional testing methods to integrating ToxCast/Tox21 in vitro high-throughput screening assays for identifying chemicals with endocrine bioactivity. The ToxCast high-throughput H295R steroidogenesis assay may potentially replace the low-throughput assays currently used in the EDSP Tier 1 battery to detect chemicals that alter the synthesis of androgens and estrogens. Herein, we describe an approach for identifying in vitro candidate reference chemicals that affect the production of androgens and estrogens in models of steroidogenesis. Candidate reference chemicals were identified from a review of H295R and gonad-derived in vitro assays used in methods validation and published in the scientific literature. A total of 29 chemicals affecting androgen and estrogen levels satisfied all criteria for positive reference chemicals, while an additional set of 21 and 15 chemicals partially fulfilled criteria for positive reference chemicals for androgens and estrogens, respectively. The identified chemicals included pesticides, pharmaceuticals, industrial and naturally-occurring chemicals with the capability to increase or decrease the levels of the sex hormones in vitro. Additionally, 14 and 15 compounds were identified as potential negative reference chemicals for effects on androgens and estrogens, respectively. These candidate reference chemicals will be informative for performance-based validation of in vitro steroidogenesis models. Copyright © 2017. Published by Elsevier Ltd.

Selected chemical compounds in firm and mellow persimmon fruit before and after the drying process.

PubMed

Senica, Mateja; Veberic, Robert; Grabnar, Jana Jurhar; Stampar, Franci; Jakopic, Jerneja

2016-07-01

Persimmon is a seasonal fruit and only available in fresh form for a short period of each year. In addition to freezing, drying is the simplest substitute for the fresh fruit and accessible throughout the year. The effect of mellowing and drying was evaluated in 'Tipo' persimmon, an astringent cultivar. 'Tipo' firm fruit contained high levels of tannins (1.1 mg g(-1) DW), which were naturally decreased to 0.2 mg g(-1) DW after mellowing. The drying process greatly impacted the contents of carotenoids, total phenols, individual phenolics, tannins, organic acids, sugars and colour parameters in firm and mellow fruit. The reduction of tannins, phenolic compounds and organic acids were accompanied by the increase of sugars and carotenoids, improving the colour of the analysed samples. These results showed that the drying process improved the quality of persimmon products and extended their shelf life. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Incorporating zebrafish omics into chemical biology and toxicology.

PubMed

Sukardi, Hendrian; Ung, Choong Yong; Gong, Zhiyuan; Lam, Siew Hong

2010-03-01

In this communication, we describe the general aspects of omics approaches for analyses of transcriptome, proteome, and metabolome, and how they can be strategically incorporated into chemical screening and perturbation studies using the zebrafish system. Pharmacological efficacy and selectivity of chemicals can be evaluated based on chemical-induced phenotypic effects; however, phenotypic observation has limitations in identifying mechanistic action of chemicals. We suggest adapting gene-expression-based high-throughput screening as a complementary strategy to zebrafish-phenotype-based screening for mechanistic insights about the mode of action and toxicity of a chemical, large-scale predictive applications and comparative analysis of chemical-induced omics signatures, which are useful to identify conserved biological responses, signaling pathways, and biomarkers. The potential mechanistic, predictive, and comparative applications of omics approaches can be implemented in the zebrafish system. Examples of these using the omics approaches in zebrafish, including data of ours and others, are presented and discussed. Omics also facilitates the translatability of zebrafish studies across species through comparison of conserved chemical-induced responses. This review is intended to update interested readers with the current omics approaches that have been applied in chemical studies on zebrafish and their potential in enhancing discovery in chemical biology.

Preparation and Characterization of SN-38-Encapsulated Phytantriol Cubosomes Containing α-Monoglyceride Additives.

PubMed

Ali, Md Ashraf; Noguchi, Shuji; Iwao, Yasunori; Oka, Toshihiko; Itai, Shigeru

2016-01-01

SN-38 is a potent active metabolite of irinotecan that has been considered as an anticancer candidate. However, the clinical development of this compound has been hampered by its poor aqueous solubility and chemical instability. In this study, we developed SN-38-encapsulated cubosomes to resolve these problems. Six α-monoglyceride additives, comprising monocaprylin, monocaprin, monolaurin, monomyristin, monopalmitin, and monostearin, were used to prepare phytantriol (PHYT) cubosomes by probe sonication. The mean particle size, polydispersity index, and zeta potential values of these systems were around 190-230 nm, 0.19-0.25 and -17 to -22 mV, respectively. Small-angle X-ray scattering analyses confirmed that the SN-38-encapsulated cubosomes existed in the Pn̄3m space group both with and without the additives. The monoglyceride additives led to around a two-fold increase in the solubility of SN-38 compared with the PHYT cubosome. The drug entrapment efficiency of PHYT cubosomes with additives was greater than 97%. The results of a stability study at 25°C showed no dramatic changes in the particle size or polydispersity index characteristics, with at least 85% of the SN-38 existing in its active lactone form after 10 d, demonstrating the high stability of the cubosome nanoparticles. Furthermore, approximately 55% of SN-38 was slowly released from the cubosomes with additives over 96 h in vitro under physiological conditions. Taken together, these results show that the SN-38-encapsulated PHYT cubosome particles are promising drug carriers that should be considered for further in vivo experiments, including drug delivery to tumor cells using the enhanced permeability and retention effect.

Improvement of Expansive Soils Using Chemical Stabilizers

NASA Astrophysics Data System (ADS)

Ikizler, S. B.; Senol, A.; Khosrowshahi, S. K.; Hatipoğlu, M.

2014-12-01

The aim of this study is to investigate the effect of two chemical stabilizers on the swelling potential of expansive soil. A high plasticity sodium bentonite was used as the expansive soil. The additive materials including fly ash (FA) and lime (L) were evaluated as potential stabilizers to decrease the swelling pressure of bentonite. Depending on the type of additive materials, they were blended with bentonite in different percentages to assess the optimum state and approch the maximum swell pressure reduction. According to the results of swell pressure test, both fly ash and lime reduce the swelling potential of bentonite but the maximum improvement occurs using bentonite-lime mixture while the swelling pressure reduction approaches to 49%. The results reveal a significant reduction of swelling potential of expansive soil using chemical stabilizers. Keywords: Expansive soil; swell pressure; chemical stabilization; fly ash; lime

Analytical methods for chemical and sensory characterization of scent-markings in large wild mammals: a review.

PubMed

Soso, Simone B; Koziel, Jacek A; Johnson, Anna; Lee, Young Jin; Fairbanks, W Sue

2014-03-05

In conjoining the disciplines of "ethology" and "chemistry" the field of "Ethochemistry" has been instituted. Ethochemistry is an effective tool in conservation efforts of endangered species and the understanding of behavioral patterns across all species. Chemical constituents of scent-markings have an important, yet poorly understood function in territoriality, reproduction, dominance, and impact on evolutionary biology, especially in large mammals. Particular attention has recently been focused on scent-marking analysis of great cats (Kalahari leopards (Panthera pardus), puma (Puma concolor) snow leopard (Panthera uncia), African lions (Panthera leo), cheetahs (Acinonyx jubatus), and tigers (Panthera tigris)) for the purpose of conservation. Sensory analyses of scent-markings could address knowledge gaps in ethochemistry. The objective of this review is to summarize the current state-of-the art of both the chemical and sensory analyses of scent-markings in wild mammals. Specific focus is placed on sampling and sample preparation, chemical analysis, sensory analysis, and simultaneous chemical and sensory analyses. Constituents of exocrine and endocrine secretions have been most commonly studied with chromatography-based analytical separations. Odor analysis of scent-markings provides an insight into the animal's sensory perception. A limited number of articles have been published in the area of sensory characterization of scent marks. Simultaneous chemical and sensory analyses with chromatography-olfactometry hyphenation could potentially aid conservation efforts by linking perceived odor, compounds responsible for odor, and resulting behavior.

Chemical and microstructural analyses for heavy metals removal from water media by ceramic membrane filtration.

PubMed

Ali, Asmaa; Ahmed, Abdelkader; Gad, Ali

2017-01-01

This study aims to investigate the ability of low cost ceramic membrane filtration in removing three common heavy metals namely; Pb 2+ , Cu 2+ , and Cd 2+ from water media. The work includes manufacturing ceramic membranes with dimensions of 15 by 15 cm and 2 cm thickness. The membranes were made from low cost materials of local clay mixed with different sawdust percentages of 0.5%, 2.0%, and 5.0%. The used clay was characterized by X-ray diffraction (XRD) and X-ray fluorescence analysis. Aqueous solutions of heavy metals were prepared in the laboratory and filtered through the ceramic membranes. The influence of the main parameters such as pH, initial driving pressure head, and concentration of heavy metals on their removal efficiency by ceramic membranes was investigated. Water samples were collected before and after the filtration process and their heavy metal concentrations were determined by chemical analysis. Moreover, a microstructural analysis using scanning electronic microscope (SEM) was performed on ceramic membranes before and after the filtration process. The chemical analysis results showed high removal efficiency up to 99% for the concerned heavy metals. SEM images approved these results by showing adsorbed metal ions on sides of the internal pores of the ceramic membranes.

Diagrams for comprehensive molecular orbital-based chemical reaction analyses: reactive orbital energy diagrams.

PubMed

Tsuneda, Takao; Singh, Raman Kumar; Chattaraj, Pratim Kumar

2018-05-15

Reactive orbital energy diagrams are presented as a tool for comprehensively performing orbital-based reaction analyses. The diagrams rest on the reactive orbital energy theory, which is the expansion of conceptual density functional theory (DFT) to an orbital energy-based theory. The orbital energies on the intrinsic reaction coordinates of fundamental reactions are calculated by long-range corrected DFT, which is confirmed to provide accurate orbital energies of small molecules, combining with a van der Waals (vdW) correlation functional, in order to examine the vdW effect on the orbital energies. By analysing the reactions based on the reactive orbital energy theory using these accurate orbital energies, it is found that vdW interactions significantly affect the orbital energies in the initial reaction processes and that more than 70% of reactions are determined to be initially driven by charge transfer, while the remaining structural deformation (dynamics)-driven reactions are classified into identity, cyclization and ring-opening, unimolecular dissociation, and H2 reactions. The reactive orbital energy diagrams, which are constructed using these results, reveal that reactions progress so as to delocalize the occupied reactive orbitals, which are determined as contributing orbitals and are usually not HOMOs, by hybridizing the unoccupied reactive orbitals, which are usually not LUMOs. These diagrams also raise questions about conventional orbital-based diagrams such as frontier molecular orbital diagrams, even for the well-established interpretation of Diels-Alder reactions.

Ultrafast chemical interface scattering as an additional decay channel for nascent nonthermal electrons in small metal nanoparticles.

PubMed

Bauer, Christophe; Abid, Jean-Pierre; Fermin, David; Girault, Hubert H

2004-05-15

The use of 4.2 nm gold nanoparticles wrapped in an adsorbates shell and embedded in a TiO2 metal oxide matrix gives the opportunity to investigate ultrafast electron-electron scattering dynamics in combination with electronic surface phenomena via the surface plasmon lifetimes. These gold nanoparticles (NPs) exhibit a large nonclassical broadening of the surface plasmon band, which is attributed to a chemical interface damping. The acceleration of the loss of surface plasmon phase coherence indicates that the energy and the momentum of the collective electrons can be dissipated into electronic affinity levels of adsorbates. As a result of the preparation process, gold NPs are wrapped in a shell of sulfate compounds that gives rise to a large density of interfacial molecules confined between Au and TiO2, as revealed by Fourier-transform-infrared spectroscopy. A detailed analysis of the transient absorption spectra obtained by broadband femtosecond transient absorption spectroscopy allows separating electron-electron and electron-phonon interaction. Internal thermalization times (electron-electron scattering) are determined by probing the decay of nascent nonthermal electrons (NNEs) and the build-up of the Fermi-Dirac electron distribution, giving time constants of 540 to 760 fs at 0.42 and 0.34 eV from the Fermi level, respectively. Comparison with literature data reveals that lifetimes of NNEs measured for these small gold NPs are more than four times longer than for silver NPs with similar sizes. The surprisingly long internal thermalization time is attributed to an additional decay mechanism (besides the classical e-e scattering) for the energy loss of NNEs, identified as the ultrafast chemical interface scattering process. NNEs experience an inelastic resonant scattering process into unoccupied electronic states of adsorbates, that directly act as an efficient heat bath, via the excitation of molecular vibrational modes. The two-temperature model is no longer

Chemical fingerprinting of naphthenic acids and oil sands process waters-A review of analytical methods for environmental samples.

PubMed

Headley, J V; Peru, K M; Mohamed, M H; Frank, R A; Martin, J W; Hazewinkel, R R O; Humphries, D; Gurprasad, N P; Hewitt, L M; Muir, D C G; Lindeman, D; Strub, R; Young, R F; Grewer, D M; Whittal, R M; Fedorak, P M; Birkholz, D A; Hindle, R; Reisdorph, R; Wang, X; Kasperski, K L; Hamilton, C; Woudneh, M; Wang, G; Loescher, B; Farwell, A; Dixon, D G; Ross, M; Pereira, A Dos Santos; King, E; Barrow, M P; Fahlman, B; Bailey, J; McMartin, D W; Borchers, C H; Ryan, C H; Toor, N S; Gillis, H M; Zuin, L; Bickerton, G; Mcmaster, M; Sverko, E; Shang, D; Wilson, L D; Wrona, F J

2013-01-01

This article provides a review of the routine methods currently utilized for total naphthenic acid analyses. There is a growing need to develop chemical methods that can selectively distinguish compounds found within industrially derived oil sands process affected waters (OSPW) from those derived from the natural weathering of oil sands deposits. Attention is thus given to the characterization of other OSPW components such as oil sands polar organic compounds, PAHs, and heavy metals along with characterization of chemical additives such as polyacrylamide polymers and trace levels of boron species. Environmental samples discussed cover the following matrices: OSPW containments, on-lease interceptor well systems, on- and off-lease groundwater, and river and lake surface waters. There are diverse ranges of methods available for analyses of total naphthenic acids. However, there is a need for inter-laboratory studies to compare their accuracy and precision for routine analyses. Recent advances in high- and medium-resolution mass spectrometry, concomitant with comprehensive mass spectrometry techniques following multi-dimensional chromatography or ion-mobility separations, have allowed for the speciation of monocarboxylic naphthenic acids along with a wide range of other species including humics. The distributions of oil sands polar organic compounds, particularly the sulphur containing species (i.e., OxS and OxS2) may allow for distinguishing sources of OSPW. The ratios of oxygen- (i.e., Ox) and nitrogen-containing species (i.e., NOx, and N2Ox) are useful for differentiating organic components derived from OSPW from natural components found within receiving waters. Synchronous fluorescence spectroscopy also provides a powerful screening technique capable of quickly detecting the presence of aromatic organic acids contained within oil sands naphthenic acid mixtures. Synchronous fluorescence spectroscopy provides diagnostic profiles for OSPW and potentially impacted

Effects of chemical additives on hydrocarbon disappearance and biodegradation in freshwater marsh microcosms.

PubMed

Nyman, J A; Klerks, P L; Bhattacharyya, S

2007-09-01

We determined how a cleaner and a dispersant affected hydrocarbon biodegradation in wetland soils dominated by the plant Panicum hemitomon, which occurs throughout North and South America. Microcosms received no hydrocarbons, South Louisiana crude, or diesel; and no additive, a dispersant, or a cleaner. We determined the concentration of four total petroleum hydrocarbon (TPH) measures and 43 target hydrocarbons in water and sediment fractions 1, 7, 31, and 186 days later. Disappearance was distinguished from biodegradation via hopane-normalization. After 186 days, TPH disappearance ranged from 24% to 97%. There was poor correlation among the four TPH measures, which indicated that each quantified a different suite of hydrocarbons. Hydrocarbon disappearance and biodegradation were unaltered by these additives under worse-case scenarios. Any use of these additives must generate benefits that outweigh the lack of effect on biodegradation demonstrated in this report, and the increase in toxicity that we reported earlier.

Photomixotrophic chemical production in cyanobacteria.

PubMed

Matson, Morgan M; Atsumi, Shota

2018-04-01

The current global dependence on fossil fuels for both energy and chemical production has spurred concerns regarding long-term resource security and environmental detriments resulting from increased CO 2 levels. Through the installation of exogenous metabolic pathways, engineered cyanobacteria strains can directly fix CO 2 into industrially relevant chemicals currently produced from petroleum. This review highlights some of the studies that have successfully implemented photomixotrophic conditions to increase cyanobacterial chemical production. Supplementation with fixed carbon sources provides additional carbon building blocks and energy to enhance production and occasionally aid in growth. Photomixotrophic production has increased titers up to 5-fold over traditional autotrophic conditions, demonstrating promising applications for future commercialization. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of liberibacter infection (huanglongbing disease) of citrus on orange fruit physiology and fruit/fruit juice quality: chemical and physical analyses.

PubMed

Baldwin, Elizabeth; Plotto, Anne; Manthey, John; McCollum, Greg; Bai, Jinhe; Irey, Mike; Cameron, Randall; Luzio, Gary

2010-01-27

More than 90% of oranges in Florida are processed, and since Huanglongbing (HLB) disease has been rumored to affect fruit flavor, chemical and physical analyses were conducted on fruit and juice from healthy (Las -) and diseased (Las +) trees on three juice processing varieties over two seasons, and in some cases several harvests. Fruit, both asymptomatic and symptomatic for the disease, were used, and fresh squeezed and processed/pasteurized juices were evaluated. Fruit and juice characteristics measured included color, size, solids, acids, sugars, aroma volatiles, ascorbic acid, secondary metabolites, pectin, pectin-demethylating enzymes, and juice cloud. Results showed that asymptomatic fruit from symptomatic trees were similar to healthy fruit for many of the quality factors measured, but that juice from asymptomatic and especially symptomatic fruits were often higher in the bitter compounds limonin and nomilin. However, values were generally below reported taste threshold levels, and only symptomatic fruit seemed likely to cause flavor problems. There was variation due to harvest date, which was often greater than that due to disease. It is likely that the detrimental flavor attributes of symptomatic fruit (which often drop off the tree) will be largely diluted in commercial juice blends that include juice from fruit of several varieties, locations, and seasons.

Diallyl disulphide as natural organosulphur friction modifier via the in-situ tribo-chemical formation of tungsten disulphide

NASA Astrophysics Data System (ADS)

Rodríguez Ripoll, Manel; Totolin, Vladimir; Gabler, Christoph; Bernardi, Johannes; Minami, Ichiro

2018-01-01

The present work shows a novel method for generating in-situ low friction tribofilms containing tungsten disulphide in lubricated contacts using diallyl disulphide as sulphur precursor. The approach relies on the tribo-chemical interaction between the diallyl disulphide and a surface containing embedded sub-micrometer tungsten carbide particles. The results show that upon sliding contact between diallyl disulphide and the tungsten-containing surface, the coefficient of friction drops to values below 0.05 after an induction period. The reason for the reduction in friction is due to tribo-chemical reactions that leads to the in-situ formation of a complex tribofilm that contains iron and tungsten components. X-ray photoelectron spectroscopy analyses indicate the presence of tungsten disulphide at the contact interface, thus justifying the low coefficient of friction achieved during the sliding experiments. It was proven that the low friction tribofilms can only be formed by the coexistence of tungsten and sulphur species, thus highlighting the synergy between diallyl disulphide and the tungsten-containing surface. The concept of functionalizing surfaces to react with specific additives opens up a wide range of possibilities, which allows tuning on-site surfaces to target additive interactions.

Physical, chemical and sensory properties of brownies substituted with sweet potato flour (Ipomoea batatas L.) with addition of black cumin oil (Nigella sativa L.)

NASA Astrophysics Data System (ADS)

Ligarnasari, I. P.; Anam, C.; Sanjaya, A. P.

2018-01-01

Effect of addition black cumin oil on the physical (hardness) characteristics, chemical (water, ash, fat, protein, carbohydrate, antioxidant IC50, total phenol and active component) characteristics and sensory (flavor, taste, texture, overall) characteristics of brownies substituted sweet potato flour were investigated. Substituted brownies was added with 0.05%, 0.10%, 0.15%, 0.20% and 0.25% of nigella sativa oil. The result showed that water content, ash, protein, fat, total phenol were increased and carbohydrate, antioxidant IC50 was decreased by the addition of nigella sativa oil. Due to the sensory characteristics, panelist gave the high score for substituted brownies which was added 0.05% nigella sativa oil. The result showed that the best formula of substituted brownies which was added 0.05% of nigella sativa oil had 24.89% water content, 1.19% ash content, 7.54% protein content, 37.79% fat content, 53.06% carbohydrate contain, 1043.6 ppm IC50 antioxidant and 0.22% total phenol. The active component on the brownies using GCMS identification were palmitic acid, oleic acid, lauric acid, theobromine and vitamin E.

Risk assessment of PCDD/Fs levels in human tissues related to major food items based on chemical analyses and micro-EROD assay.

PubMed

Tsang, H L; Wu, S C; Wong, C K C; Leung, C K M; Tao, S; Wong, M H

2009-10-01

Nine groups of food items (freshwater fish, marine fish, pork, chicken, chicken eggs, leafy, non-leafy vegetables, rice and flour) and three types of human samples (human milk, maternal serum and cord serum) were collected for the analysis of PCDD/Fs. Results of chemical analysis revealed PCDD/Fs concentrations (pg g(-1) fat) in the following ascending order: pork (0.289 pg g(-1) fat), grass carp (Ctenopharyngodon idellus) (freshwater fish) (0.407), golden thread (Nemipterus virgatus) (marine fish) (0.511), chicken (0.529), mandarin fish (Siniperca kneri) (marine fish) (0.535), chicken egg (0.552), and snubnose pompano (Trachinotus blochii) (marine fish) (1.219). The results of micro-EROD assay showed relatively higher PCDD/Fs levels in fish (2.65 pg g(-1) fat) when compared with pork (0.47), eggs (0.33), chicken (0.13), flour (0.07), vegetables (0.05 pg g(-1) wet wt) and rice (0.05). The estimated average daily intake of PCDD/Fs of 3.51 pg EROD-TEQ/kg bw/day was within the range of WHO Tolerable Daily Intake (1-4 pg WHO-TEQ/kg bw/day) and was higher than the Provisional Tolerable Daily Intake (PMTL) (70 pg for dioxins and dioxin-like PCBs) recommended by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) [Joint FAO/WHO Expert Committee on Food Additives (JECFA), Summary and conclusions of the fifty-seventh meeting, JECFA, 2001.]. Nevertheless, the current findings were significantly lower than the TDI (14 pg WHO-TEQ/kg/bw/day) recommended by the Scientific Committee on Food of the Europe Commission [European Scientific Committee on Food (EU SCF), Opinions on the SCF on the risk assessment of dioxins and dioxin-like PCBs in food, 2000.]. However, it should be noted that micro-EROD assay overestimates the PCDD/Fs levels by 2 to 7 folds which may also amplify the PCDD/Fs levels accordingly. Although the levels of PCDD/Fs obtained from micro-EROD assay were much higher than those obtained by chemical analysis by 2 to 7 folds, it provides a cost-effective and

Effect of salt additives on concrete degradation : interim report

DOT National Transportation Integrated Search

1993-06-01

Many chemical additives designed to inhibit the corrosive effect of salt on rebars are being marketed. Their effect on Portland Cement Concrete is neither known nor understood. This study is an attempt to determine if there is an effect and to unders...

Calibration and use of the polar organic chemical integrative sampler--a critical review.

PubMed

Harman, Christopher; Allan, Ian John; Vermeirssen, Etiënne L M

2012-12-01

The implementation of strict environmental quality standards for polar organic priority pollutants poses a challenge for monitoring programs. The polar organic chemical integrative sampler (POCIS) may help to address the challenge of measuring low and fluctuating trace concentrations of such organic contaminants, offering significant advantages over traditional sampling. In the present review, the authors evaluate POCIS calibration methods and factors affecting sampling rates together with reported environmental applications. Over 300 compounds have been shown to accumulate in POCIS, including pesticides, pharmaceuticals, hormones, and industrial chemicals. Polar organic chemical integrative sampler extracts have been used for both chemical and biological analyses. Several different calibration methods have been described, which makes it difficult to directly compare sampling rates. In addition, despite the fact that some attempts to correlate sampling rates with the properties of target compounds such as log K(OW) have been met with varying success, an overall model that can predict uptake is lacking. Furthermore, temperature, water flow rates, salinity, pH, and fouling have all been shown to affect uptake; however, there is currently no robust method available for adjusting for these differences. Overall, POCIS has been applied to a wide range of sampling environments and scenarios and has been proven to be a useful screening tool. However, based on the existing literature, a more mechanistic approach is required to increase understanding and thus improve the quantitative nature of the measurements. Copyright © 2012 SETAC.

Probabilistic Exposure Analysis for Chemical Risk Characterization

PubMed Central

Bogen, Kenneth T.; Cullen, Alison C.; Frey, H. Christopher; Price, Paul S.

2009-01-01

This paper summarizes the state of the science of probabilistic exposure assessment (PEA) as applied to chemical risk characterization. Current probabilistic risk analysis methods applied to PEA are reviewed. PEA within the context of risk-based decision making is discussed, including probabilistic treatment of related uncertainty, interindividual heterogeneity, and other sources of variability. Key examples of recent experience gained in assessing human exposures to chemicals in the environment, and other applications to chemical risk characterization and assessment, are presented. It is concluded that, although improvements continue to be made, existing methods suffice for effective application of PEA to support quantitative analyses of the risk of chemically induced toxicity that play an increasing role in key decision-making objectives involving health protection, triage, civil justice, and criminal justice. Different types of information required to apply PEA to these different decision contexts are identified, and specific PEA methods are highlighted that are best suited to exposure assessment in these separate contexts. PMID:19223660

Quarterly progress report for the Chemical and Energy Research Section of the Chemical Technology Division, April--June 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jubin, R.T.

The Chemical and Energy Research Section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within six major areas of research: Hot Cell Operations, Process Chemistry and thermodynamics, Separations and Materials Synthesis, Solution Thermodynamics, biotechnology Research, and Molecular Studies. The name of a technical contact is included with each task described, and readers are encouraged to contact these individuals if they need additional information.

Investigation of Acrylic Resin Disinfection Using Chemicals and Ultrasound.

PubMed

Muscat, Ylainia; Farrugia, Cher; Camilleri, Liberato; Arias-Moliz, Maria Teresa; Valdramidis, Vasilis; Camilleri, Josette

2018-06-01

Dental prosthetic and orthodontic appliances are transported from the clinic to the laboratory for additions and repairs. These appliances, containing microbes from the oral flora, are a high risk for cross-contamination. The aim of this study was to evaluate the effect of chemical and ultrasound disinfection against two in vitro biofilms and an in vivo formed biofilm grown on unprepared and polished polymethyl methacrylate (PMMA) surfaces. Rough and polished self-curing PMMA surfaces were infected with strains of both Candida albicans and Streptococcus oralis. After incubation, the samples were treated with different disinfection methods, including ultrasound treatment for both 15 and 30 seconds, and immersion in glutaraldehyde and alcohol-based chemical disinfectants (MD520 and Minuten, respectively). The disinfecting efficacy was assessed by colony forming units (CFU) analysis and by scanning electron microscopy (SEM). Furthermore the adequacy of bacterial elimination of application of 30-second ultrasound and MD520 was assessed on PMMA retrieved from ten volunteers by CFU analyses. ANOVA with p = 0.05 followed by the Tukey post hoc test and the Student t-test was used to analyze the data. The ultrasound treatment for 30 seconds, MD520, and Minuten were the most effective disinfectant methods as they reduced the microbial counts compared to the control (p < 0.05) as shown in the in vitro analyses. S. oralis adhered more to rough acrylic resin surfaces (p < 0.05). Ultrasound treatment was the most effective way to reduce microbial counts on PMMA exposed to oral flora (p = 0.043). Ultrasound treatment for 30 seconds was effective against C. albicans, S. oralis, and the oral flora as shown by testing microbial growth on agar plates and SEM. © 2016 by the American College of Prosthodontists.

Real-time chemical characterization of atmospheric particulate matter in China: A review

NASA Astrophysics Data System (ADS)

Li, Yong Jie; Sun, Yele; Zhang, Qi; Li, Xue; Li, Mei; Zhou, Zhen; Chan, Chak K.

2017-06-01

Atmospheric particulate matter (PM) pollution has become a major health threat accompanying the rapid economic development in China. For decades, filter-based offline chemical analyses have been the most widely adopted means to investigate PM and have provided much information for understanding this type of pollution in China. However, offline analyses have low time resolutions and the chemical information thus obtained fail to reflect the dynamic nature of the sources and the rapid processes leading to the severe PM pollution in China. In recent years, advances in real-time PM chemical characterization have created a new paradigm for PM studies in China. In this review, we summarize those advances, focusing on the most widely used mass spectrometric and ion chromatographic techniques. We describe the findings from those studies in terms of spatiotemporal variabilities, degree of neutralization and oxygenation, source apportionment, secondary formation, as well as collocated measurements of the chemical and physical (hygroscopic and optical) properties of PM. We also highlight the new insights gained from those findings and suggest future directions for further advancing our understanding of PM pollution in China via real-time chemical characterization.

Comparative chemical analyses of soils formed on carbonate rocks in Hungary

NASA Astrophysics Data System (ADS)

Németh, Eszter; Sajó, István; Bidló, András

2014-05-01

The present study focuses on the physical and chemical investigation of soils formed primarily on carbonate rocks. One part of the investigated soil profiles originated from the top of the Bükk Hills, the Bükk-Highlands' limestone plateau, which is located in the North-Eastern part of Hungary. The rest of the samples were taken from the Szárhalom Forest (located in West Hungary). The different location and climate of the sites forms a basis of the comparison of the soils with similar base rock. These soils are formed mainly on limestones, however they differ significantly in terms of certain characteristic properties. The following physical parameters were evaluated from the samples: transition, structure, compactness, roots, skeletal percent, colour, physical assortment, concretion and soil defect. Laboratory analysis involved the measurement of acidity, particle distribution, carbonated lime content, humus content, ammonium lactate-acetic acid soluble phosphorus- and potassium content, potassium chloride soluble calcium- and magnesium content, ethylene-diamine-tetraacetic-acid (EDTA) and diethylene-triamine-pentaacetic-acid (DTPA) soluble copper-, iron-, manganese- and zinc content. X-ray diffraction, thermoanalytical measurements and ICP-OES were also carried out to determine the mineral composition of the soils and the content of heavy metals. Evaluation focused on the comprehensive analysis of the data with a special regard to possible relationships and correlations. Research was supported financially by the "Silva naturalis (TÁMOP-4.2.2.A-11/1/KONV-2012-0004)" project.

Food additives and preschool children.

PubMed

Martyn, Danika M; McNulty, Breige A; Nugent, Anne P; Gibney, Michael J

2013-02-01

Food additives have been used throughout history to perform specific functions in foods. A comprehensive framework of legislation is in place within Europe to control the use of additives in the food supply and ensure they pose no risk to human health. Further to this, exposure assessments are regularly carried out to monitor population intakes and verify that intakes are not above acceptable levels (acceptable daily intakes). Young children may have a higher dietary exposure to chemicals than adults due to a combination of rapid growth rates and distinct food intake patterns. For this reason, exposure assessments are particularly important in this age group. The paper will review the use of additives and exposure assessment methods and examine factors that affect dietary exposure by young children. One of the most widely investigated unfavourable health effects associated with food additive intake in preschool-aged children are suggested adverse behavioural effects. Research that has examined this relationship has reported a variety of responses, with many noting an increase in hyperactivity as reported by parents but not when assessed using objective examiners. This review has examined the experimental approaches used in such studies and suggests that efforts are needed to standardise objective methods of measuring behaviour in preschool children. Further to this, a more holistic approach to examining food additive intakes by preschool children is advisable, where overall exposure is considered rather than focusing solely on behavioural effects and possibly examining intakes of food additives other than food colours.

EAST ELEVATION OF HIGH BAY ADDITION OF FUEL STORAGE BUILDING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

EAST ELEVATION OF HIGH BAY ADDITION OF FUEL STORAGE BUILDING (CPP-603). INL DRAWING NUMBER 200-0603-00-706-051286. - Idaho National Engineering Laboratory, Idaho Chemical Processing Plant, Fuel Reprocessing Complex, Scoville, Butte County, ID

The Effects of Chemical Wash Additives on the Corrosion of Aerospace Alloys in Marine Environments

NASA Technical Reports Server (NTRS)

MacDowell, Louis; Calle, Luz Marina; Curran, Joseph; Hodge, Tim; Barile, Ronald; Heidersbach, Robert; Steinrock, T. (Technical Monitor)

2002-01-01

This paper presents the methodology for comparing the relative effectiveness of four chemical products used for rinsing airplanes and helicopters. The products were applied on a weekly basis to a series of flat alloy panels exposed to an oceanfront marine environment for one year. The results are presented along with comparisons of exposures of the same alloys that were not washed, were washed with seawater, or washed with de-ionized water.

An experiment in software reliability: Additional analyses using data from automated replications

NASA Technical Reports Server (NTRS)

Dunham, Janet R.; Lauterbach, Linda A.

1988-01-01

A study undertaken to collect software error data of laboratory quality for use in the development of credible methods for predicting the reliability of software used in life-critical applications is summarized. The software error data reported were acquired through automated repetitive run testing of three independent implementations of a launch interceptor condition module of a radar tracking problem. The results are based on 100 test applications to accumulate a sufficient sample size for error rate estimation. The data collected is used to confirm the results of two Boeing studies reported in NASA-CR-165836 Software Reliability: Repetitive Run Experimentation and Modeling, and NASA-CR-172378 Software Reliability: Additional Investigations into Modeling With Replicated Experiments, respectively. That is, the results confirm the log-linear pattern of software error rates and reject the hypothesis of equal error rates per individual fault. This rejection casts doubt on the assumption that the program's failure rate is a constant multiple of the number of residual bugs; an assumption which underlies some of the current models of software reliability. data raises new questions concerning the phenomenon of interacting faults.

Modular Chemical Descriptor Language (MCDL): Stereochemical modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gakh, Andrei A; Burnett, Michael N; Trepalin, Sergei V.

2011-01-01

In our previous papers we introduced the Modular Chemical Descriptor Language (MCDL) for providing a linear representation of chemical information. A subsequent development was the MCDL Java Chemical Structure Editor which is capable of drawing chemical structures from linear representations and generating MCDL descriptors from structures. In this paper we present MCDL modules and accompanying software that incorporate unique representation of molecular stereochemistry based on Cahn-Ingold-Prelog and Fischer ideas in constructing stereoisomer descriptors. The paper also contains additional discussions regarding canonical representation of stereochemical isomers, and brief algorithm descriptions of the open source LINDES, Java applet, and Open Babel MCDLmore » processing module software packages. Testing of the upgraded MCDL Java Chemical Structure Editor on compounds taken from several large and diverse chemical databases demonstrated satisfactory performance for storage and processing of stereochemical information in MCDL format.« less

Desorption kinetics of organic chemicals from albumin.

PubMed

Krause, Sophia; Ulrich, Nadin; Goss, Kai-Uwe

2018-03-01

When present in blood, most chemicals tend to bind to the plasma protein albumin. For distribution into surrounding tissues, desorption from albumin is necessary, because only the unbound form of a chemical is assumed to be able to cross cell membranes. For metabolism of chemicals, the liver is a particularly important organ. One potentially limiting step for hepatic uptake of the chemicals is desorption from albumin, because blood passes the human liver within seconds. Desorption kinetics from albumin can thus be an important parameter for our pharmacokinetic and toxicokinetic understanding of chemicals. This work presents a dataset of measured desorption rate constants and reveals a possibility for their prediction. Additionally, the obtained extraction profiles directly indicate physiological relevance of desorption kinetics, because desorption of the test chemicals is still incomplete after time frames comparable to the residence time of blood in the liver.

Operational and biological analyses of branched water-adjustment and combined treatment of wastewater from a chemical industrial park.

PubMed

Xu, Ming; Cao, Jiashun; Li, Chao; Tu, Yong; Wu, Haisuo; Liu, Weijing

2018-01-01

The combined biological processes of branched water-adjustment, chemical precipitation, hydrolysis acidification, secondary sedimentation, Anoxic/Oxic and activated carbon treatment were used for chemical industrial wastewater treatment in the Taihu Lake Basin. Full-scale treatment resulted in effluent chemical oxygen demand, total nitrogen, NH 3 -N and total phosphorus of 35.1, 5.20, 3.10 and 0.15 mg/L, respectively, with a total removal efficiency of 91.1%, 67.1%, 70.5% and 89.3%, respectively. In this process, short-circuited organic carbon from brewery wastewater was beneficial for denitrification and second-sulfate reduction. The concentration of effluent fluoride was 6.22 mg/L, which also met the primary standard. Gas Chromatography-Mass Spectrometry analysis revealed that many types of refractory compounds were present in the inflow. Microbial community analysis performed in the summer by PCR-denaturing gradient gel electrophoresis and MiSeq demonstrated that certain special functional bacteria, such as denitrificans, phosphorus-accumulating bacteria, sulfate- and perhafnate-reducing bacteria, aromatic compound-degrading bacteria and organic fluoride-degrading bacteria, present in the bio-tanks were responsible for the acceptable specific biological pollutant reduction achieved.

10 CFR 52.158 - Contents of application; additional technical information.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Contents of application; additional technical information... APPROVALS FOR NUCLEAR POWER PLANTS Manufacturing Licenses § 52.158 Contents of application; additional technical information. The application must contain: (a)(1) Inspections, tests, analyses, and acceptance...

Chemical and biological consequences of using carbon dioxide versus acid additions in ocean acidification experiments

USGS Publications Warehouse

Yates, Kimberly K.; DuFore, Christopher M.; Robbins, Lisa L.

2013-01-01

Use of different approaches for manipulating seawater chemistry during ocean acidification experiments has confounded comparison of results from various experimental studies. Some of these discrepancies have been attributed to whether addition of acid (such as hydrochloric acid, HCl) or carbon dioxide (CO2) gas has been used to adjust carbonate system parameters. Experimental simulations of carbonate system parameter scenarios for the years 1766, 2007, and 2100 were performed using the carbonate speciation program CO2SYS to demonstrate the variation in seawater chemistry that can result from use of these approaches. Results showed that carbonate system parameters were 3 percent and 8 percent lower than target values in closed-system acid additions, and 1 percent and 5 percent higher in closed-system CO2 additions for the 2007 and 2100 simulations, respectively. Open-system simulations showed that carbonate system parameters can deviate by up to 52 percent to 70 percent from target values in both acid addition and CO2 addition experiments. Results from simulations for the year 2100 were applied to empirically derived equations that relate biogenic calcification to carbonate system parameters for calcifying marine organisms including coccolithophores, corals, and foraminifera. Calculated calcification rates for coccolithophores, corals, and foraminifera differed from rates at target conditions by 0.5 percent to 2.5 percent in closed-system CO2 gas additions, from 0.8 percent to 15 percent in the closed-system acid additions, from 4.8 percent to 94 percent in open-system acid additions, and from 7 percent to 142 percent in open-system CO2 additions.

A Four-step Approach for Evaluation of Dose Additivity

EPA Science Inventory

A four step approach was developed for evaluating toxicity data on a chemical mixture for consistency with dose addition. Following the concepts in the U.S. EPA mixture guidance (EPA 2000), toxicologic interaction for a defined mixture (all components known) is departure from a c...

Neurotoxicological and statistical analyses of a mixture of five organophosphorus pesticides using a ray design.

PubMed

Moser, V C; Casey, M; Hamm, A; Carter, W H; Simmons, J E; Gennings, C

2005-07-01

Environmental exposures generally involve chemical mixtures instead of single chemicals. Statistical models such as the fixed-ratio ray design, wherein the mixing ratio (proportions) of the chemicals is fixed across increasing mixture doses, allows for the detection and characterization of interactions among the chemicals. In this study, we tested for interaction(s) in a mixture of five organophosphorus (OP) pesticides (chlorpyrifos, diazinon, dimethoate, acephate, and malathion). The ratio of the five pesticides (full ray) reflected the relative dietary exposure estimates of the general population as projected by the US EPA Dietary Exposure Evaluation Model (DEEM). A second mixture was tested using the same dose levels of all pesticides, but excluding malathion (reduced ray). The experimental approach first required characterization of dose-response curves for the individual OPs to build a dose-additivity model. A series of behavioral measures were evaluated in adult male Long-Evans rats at the time of peak effect following a single oral dose, and then tissues were collected for measurement of cholinesterase (ChE) activity. Neurochemical (blood and brain cholinesterase [ChE] activity) and behavioral (motor activity, gait score, tail-pinch response score) endpoints were evaluated statistically for evidence of additivity. The additivity model constructed from the single chemical data was used to predict the effects of the pesticide mixture along the full ray (10-450 mg/kg) and the reduced ray (1.75-78.8 mg/kg). The experimental mixture data were also modeled and statistically compared to the additivity models. Analysis of the 5-OP mixture (the full ray) revealed significant deviation from additivity for all endpoints except tail-pinch response. Greater-than-additive responses (synergism) were observed at the lower doses of the 5-OP mixture, which contained non-effective dose levels of each of the components. The predicted effective doses (ED20, ED50) were about half

Efficient exploration of chemical space by fragment-based screening.

PubMed

Hall, Richard J; Mortenson, Paul N; Murray, Christopher W

2014-01-01

Screening methods seek to sample a vast chemical space in order to identify starting points for further chemical optimisation. Fragment based drug discovery exploits the superior sampling of chemical space that can be achieved when the molecular weight is restricted. Here we show that commercially available fragment space is still relatively poorly sampled and argue for highly sensitive screening methods to allow the detection of smaller fragments. We analyse the properties of our fragment library versus the properties of X-ray hits derived from the library. We particularly consider properties related to the degree of planarity of the fragments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fate of chemical warfare agents and toxic industrial chemicals in landfills.

PubMed

Bartelt-Hunt, Shannon L; Barlaz, Morton A; Knappe, Detlef R U; Kjeldsen, Peter

2006-07-01

One component of preparedness for a chemical attack is planning for the disposal of contaminated debris. To assess the feasibility of contaminated debris disposal in municipal solid waste (MSW) landfills, the fate of selected chemical warfare agents (CWAs) and toxic industrial chemicals (TICs) in MSW landfills was predicted with a mathematical model. Five blister agents [sulfur mustard (HD), nitrogen mustard (HN-2), lewisite (L), ethyldichloroarsine (ED), and phosgene oxime (CX)], eight nerve agents [tabun (GA), sarin (GB), soman (GD), GE, GF, VX, VG, and VM], one riot-control agent [CS], and two TICs [furan and carbon disulfide] were studied. The effects of both infiltration (climate) and contaminant biodegradability on fate predictions were assessed. Model results showed that hydrolysis and gas-phase advection were the principal fate pathways for CWAs and TICs, respectively. Apart from CX and the TICs, none of the investigated compounds was predicted to persist in a landfill for more than 5 years. Climate had little impact on CWA/TIC fate, and biodegradability was only important for compounds with long hydrolysis half-lives. Monte Carlo simulations were performed to assess the influence of uncertainty in model input parameters on CWA/TIC fate predictions. Correlation analyses showed that uncertainty in hydrolysis rate constants was the primary contributor to variance of CWA fate predictions, while uncertainty in the Henry's Law constant and landfill gas-production rate accounted for most of the variance of TIC fate predictions. CWA hydrolysates were more persistent than the parent CWAs, but limited information is available on abiotic or biotic transformation rates for these chemicals.

The Chemical Decomposition of 5-aza-2′-deoxycytidine (Decitabine): Kinetic Analyses and Identification of Products by NMR, HPLC, and Mass Spectrometry

PubMed Central

Rogstad, Daniel K.; Herring, Jason L.; Theruvathu, Jacob A.; Burdzy, Artur; Perry, Christopher C.; Neidigh, Jonathan W.; Sowers, Lawrence C.

2014-01-01

The nucleoside analog 5-aza-2′-deoxycytidine (Decitabine, DAC) is one of several drugs in clinical use that inhibit DNA methyltransferases, leading to a decrease of 5-methylcytosine in newly replicated DNA and subsequent transcriptional activation of genes silenced by cytosine methylation. In addition to methyltransferase inhibition, DAC has demonstrated toxicity and potential mutagenicity, and can induce a DNA-repair response. The mechanisms accounting for these events are not well understood. DAC is chemically unstable in aqueous solutions, but there is little consensus between previous reports as to its half-life and corresponding products of decomposition at physiological temperature and pH, potentially confounding studies on its mechanism of action and long-term use in humans. Here we have employed a battery of analytical methods to estimate kinetic rates and to characterize DAC decomposition products under conditions of physiological temperature and pH. Our results indicate that DAC decomposes into a plethora of products, formed by hydrolytic opening and deformylation of the triazine ring, in addition to anomerization and possibly other changes in the sugar ring structure. We also discuss the advantages and problems associated with each analytical method used. The results reported here will facilitate ongoing studies and clinical trials aimed at understanding the mechanisms of action, toxicity, and possible mutagenicity of DAC and related analogs. PMID:19480391

Chemical composition of atmospheric aerosols resolved via positive matrix factorization

NASA Astrophysics Data System (ADS)