Nature and Analysis of Chemical Species.

ERIC Educational Resources Information Center

Shuman, Mark S.; Fogleman, Wavell W.

1978-01-01

Presents a literature review of the nature and analysis of chemical species in water, covering publications of 1976-77. This review is concerned with inorganics, and it covers: (1) electrochemical analysis; (2) spectroscopy; (3) neutron activation, radiochemical analysis, and isotope dilution. A list of 262 references is also presented. (HM)

Application of Solid Phase Microextraction with Gas Chromatography-Mass Spectrometry as a Rapid, Reliable, and Safe Method for Field Sampling and Analysis of Chemical Warfare Agent Precursors

DTIC Science & Technology

2005-03-01

in hair samples with analysis by GC-MS [41,42]. The research discussed here examined a polydimethylsiloxane polymer with 10% activated charcoal (PDMS...Field Sampling and Analysis of Chemical Warfare Agent Precursors” Name of Candidate: LT Douglas Parrish Doctor of Philosophy, Environmental...Microextraction with Gas Chromatography-Mass Spectrometry as a Rapid, Reliable, and Safe Method for Field Sampling and Analysis of Chemical Warfare

Chemical Engineering Data Analysis Made Easy with DataFit

ERIC Educational Resources Information Center

Brenner, James R.

2006-01-01

The outline for half of a one-credit-hour course in analysis of chemical engineering data is presented, along with a range of typical problems encountered later on in the chemical engineering curriculum that can be used to reinforce the data analysis skills learned in the course. This mini course allows students to be exposed to a variety of ChE…

Theory, Image Simulation, and Data Analysis of Chemical Release Experiments

NASA Technical Reports Server (NTRS)

Wescott, Eugene M.

1994-01-01

The final phase of Grant NAG6-1 involved analysis of physics of chemical releases in the upper atmosphere and analysis of data obtained on previous NASA sponsored chemical release rocket experiments. Several lines of investigation of past chemical release experiments and computer simulations have been proceeding in parallel. This report summarizes the work performed and the resulting publications. The following topics are addressed: analysis of the 1987 Greenland rocket experiments; calculation of emission rates for barium, strontium, and calcium; the CRIT 1 and 2 experiments (Collisional Ionization Cross Section experiments); image calibration using background stars; rapid ray motions in ionospheric plasma clouds; and the NOONCUSP rocket experiments.

Methods for improved preconcentrators

DOEpatents

Manginell, Ronald P [Albuquerque, NM; Lewis, Patrick R [Albuquerque, NM; Okandan, Murat [Edgewood, NM

2010-06-01

The present invention relates generally to chemical analysis (e.g. by gas chromatography), and in particular to a compact chemical preconcentrator formed on a substrate with a heatable sorptive membrane that can be used to accumulate and concentrate one or more chemical species of interest over time and then rapidly release the concentrated chemical species upon demand for chemical analysis.

Spectroscopic Chemical Analysis Methods and Apparatus

NASA Technical Reports Server (NTRS)

Hug, William F. (Inventor); Lane, Arthur L. (Inventor); Bhartia, Rohit (Inventor); Reid, Ray D. (Inventor)

2017-01-01

Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

Spectroscopic Chemical Analysis Methods and Apparatus

NASA Technical Reports Server (NTRS)

Hug, William F. (Inventor); Lane, Arthur L. (Inventor); Reid, Ray D. (Inventor); Bhartia, Rohit (Inventor)

2018-01-01

Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

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

Hoette, Trisha Marie

Throughout history, as new chemical threats arose, strategies for the defense against chemical attacks have also evolved. As a part of an Early Career Laboratory Directed Research and Development project, a systems analysis of past, present, and future chemical terrorism scenarios was performed to understand how the chemical threats and attack strategies change over time. For the analysis, the difficulty in executing chemical attack was evaluated within a framework of three major scenario elements. First, historical examples of chemical terrorism were examined to determine how the use of chemical threats, versus other weapons, contributed to the successful execution of themore » attack. Using the same framework, the future of chemical terrorism was assessed with respect to the impact of globalization and new technologies. Finally, the efficacy of the current defenses against contemporary chemical terrorism was considered briefly. The results of this analysis justify the need for continued diligence in chemical defense.« less

A PROPOSED CHEMICAL INFORMATION AND DATA SYSTEM. VOLUME I.

DTIC Science & Technology

CHEMICAL COMPOUNDS, *DATA PROCESSING, *INFORMATION RETRIEVAL, * CHEMICAL ANALYSIS, INPUT OUTPUT DEVICES, COMPUTER PROGRAMMING, CLASSIFICATION...CONFIGURATIONS, DATA STORAGE SYSTEMS, ATOMS, MOLECULES, PERFORMANCE( ENGINEERING ), MAINTENANCE, SUBJECT INDEXING, MAGNETIC TAPE, AUTOMATIC, MILITARY REQUIREMENTS, TYPEWRITERS, OPTICS, TOPOLOGY, STATISTICAL ANALYSIS, FLOW CHARTING.

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

Not Available

This purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year 1990. The ACL has four technical groups -- Chemical Analysis, Instrumental Analysis, Organic Analysis, and Environmental Analysis. The Chemical Analysis Group uses wet-chemical and instrumental methods for elemental, compositional, and isotopic analyses of solid, liquid, and gaseous samples and provides specialized analytical services. The Instrumental Analysis Group uses nuclear counting techniques in radiochemical analyses over a wide range of sample types from low-level environmental samples to samples of high radioactivity. The Organic Analysis Group uses amore » number of complementary techniques to separate and to quantitatively and qualitatively analyze complex organic mixtures and compounds at the trace level, including synthetic fuels, toxic substances, fossil-fuel residues and emissions, pollutants, biologically active compounds, pesticides, and drugs. The Environmental Analysis Group performs analyses of inorganic environmental and hazardous waste and coal samples.« less

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

Not Available

This volume contains appendices for the following: Rocky Flats Plant and Idaho National Engineering Laboratory waste process information; TRUPACT-II content codes (TRUCON); TRUPACT-II chemical list; chemical compatibility analysis for Rocky Flats Plant waste forms; chemical compatibility analysis for waste forms across all sites; TRU mixed waste characterization database; hazardous constituents of Rocky Flats Transuranic waste; summary of waste components in TRU waste sampling program at INEL; TRU waste sampling program; and waste analysis data.

Laser applications to chemical analysis: an introduction by the feature editors

NASA Astrophysics Data System (ADS)

Jeffries, Jay B.; Ramsey, J. Michael; Lucht, Robert P.

1995-06-01

This issue of Applied Optics features papers on the application of laser technology to chemical analysis. Many of the contributions, although not all, result from papers presented at the Fourth OSA Topical Meeting on Laser Applications to Chemical Analysis, which was held at Jackson Hole, Wyoming, March, 1994. This successful meeting, with nearly one hundred participants, continued the tradition of earlier LACA meetings to focus on the optical science of laser-based measurements of temperature and trace chemical assays in a wide variety of practical applications.

Photoacoustic physio-chemical analysis and its implementation in deep tissue with a catheter setup

NASA Astrophysics Data System (ADS)

Xu, Guan; Meng, Zhou-xian; Lin, Jian-die D.; Cheng, Qian; Wang, Xueding

2015-03-01

Photoacoustic (PA) measurements encode the information associated with both physical microstructures and chemical contents in biological tissues. A two-dimensional physio-chemical spectrogram (PCS) can be formulated by combining the power spectra of PA signals acquired at a series of optical wavelengths. The analysis of PCS, or namely PA physio-chemical analysis (PAPCA), enables the quantification of the relative concentrations and the spatial distributions of a variety of chemical components in the tissue. This study validated the feasibility of PAPCA in characterizing liver conditions during the progression of non-alcoholic fatty liver disease. A catheter based setup facilitating measurement in deep tissues was also tested.

Different Models Used to Interpret Chemical Changes: Analysis of a Curriculum and Its Impact on French Students' Reasoning

ERIC Educational Resources Information Center

Kermen, Isabelle; Meheut, Martine

2009-01-01

We present an analysis of the new French curriculum on chemical changes describing the underlying models and highlighting their relations to the empirical level. The authors of the curriculum introduced a distinction between the chemical change of a chemical system and the chemical reactions that account for it. We specify the different roles of…

Method for combined biometric and chemical analysis of human fingerprints.

PubMed

Staymates, Jessica L; Orandi, Shahram; Staymates, Matthew E; Gillen, Greg

This paper describes a method for combining direct chemical analysis of latent fingerprints with subsequent biometric analysis within a single sample. The method described here uses ion mobility spectrometry (IMS) as a chemical detection method for explosives and narcotics trace contamination. A collection swab coated with a high-temperature adhesive has been developed to lift latent fingerprints from various surfaces. The swab is then directly inserted into an IMS instrument for a quick chemical analysis. After the IMS analysis, the lifted print remains intact for subsequent biometric scanning and analysis using matching algorithms. Several samples of explosive-laden fingerprints were successfully lifted and the explosives detected with IMS. Following explosive detection, the lifted fingerprints remained of sufficient quality for positive match scores using a prepared gallery consisting of 60 fingerprints. Based on our results ( n  = 1200), there was no significant decrease in the quality of the lifted print post IMS analysis. In fact, for a small subset of lifted prints, the quality was improved after IMS analysis. The described method can be readily applied to domestic criminal investigations, transportation security, terrorist and bombing threats, and military in-theatre settings.

40 CFR 761.253 - Chemical analysis.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Chemical analysis. 761.253 Section 761.253 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT... Sample Sites, Collecting Surface Samples, and Analyzing Standard PCB Wipe Samples § 761.253 Chemical...

40 CFR 761.253 - Chemical analysis.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Chemical analysis. 761.253 Section 761.253 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT... Sample Sites, Collecting Surface Samples, and Analyzing Standard PCB Wipe Samples § 761.253 Chemical...

40 CFR 761.253 - Chemical analysis.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Chemical analysis. 761.253 Section 761.253 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT... Sample Sites, Collecting Surface Samples, and Analyzing Standard PCB Wipe Samples § 761.253 Chemical...

40 CFR 761.253 - Chemical analysis.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Chemical analysis. 761.253 Section 761.253 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT... Sample Sites, Collecting Surface Samples, and Analyzing Standard PCB Wipe Samples § 761.253 Chemical...

40 CFR 761.253 - Chemical analysis.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Chemical analysis. 761.253 Section 761.253 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT... Sample Sites, Collecting Surface Samples, and Analyzing Standard PCB Wipe Samples § 761.253 Chemical...

Chemical properties and methods of analysis of refractory compounds

NASA Technical Reports Server (NTRS)

Samsonov, G. V. (Editor); Frantsevich, I. N. (Editor); Yeremenko, V. N. (Editor); Nazarchuk, T. N. (Editor); Popova, O. I. (Editor)

1978-01-01

Reactions involving refractory metals and the alloys based on them are discussed. Chemical, electrochemical, photometric, spectrophotometric, and X-ray analysis are among the methods described for analyzing the results of the reactions and for determining the chemical properties of these materials.

30 CFR 784.22 - Geologic information.

Code of Federal Regulations, 2010 CFR

2010-07-01

... occurring; (ii) Chemical analyses identifying those strata that may contain acid- or toxic-forming, or... that the analysis for alkalinity-producing material is unnecessary; and (iii) Chemical analysis of the...; (ii) Chemical analyses for acid- or toxic-forming or alkalinity-producing materials and their content...

An Investigation of the Effects of Deposit Feeding Invertebrates on the Structural Properties of Clay Minerals.

DTIC Science & Technology

1981-07-01

Dennis M. Lavoie of NORDA for chemical analysis of clay minerals with the x-ray energy dispersive spectrometer. We thank Fred Bowles, Peter Fleischer...diffractograi of Nuculana acuta fecal pellet 11 residue (illite experiment). TABLES TABLE 1. X-ray energy dispersive spectrometer chemical 8 analysis for...inontmorillonite experiments. Counts for elements after background counts removed. TABLE 2. X-ray energy dispersive spectroneter chemical analysis 12 for

Natural chemical shielding analysis of nuclear magnetic resonance shielding tensors from gauge-including atomic orbital calculations

NASA Astrophysics Data System (ADS)

Bohmann, Jonathan A.; Weinhold, Frank; Farrar, Thomas C.

1997-07-01

Nuclear magnetic shielding tensors computed by the gauge including atomic orbital (GIAO) method in the Hartree-Fock self-consistent-field (HF-SCF) framework are partitioned into magnetic contributions from chemical bonds and lone pairs by means of natural chemical shielding (NCS) analysis, an extension of natural bond orbital (NBO) analysis. NCS analysis complements the description provided by alternative localized orbital methods by directly calculating chemical shieldings due to delocalized features in the electronic structure, such as bond conjugation and hyperconjugation. Examples of NCS tensor decomposition are reported for CH4, CO, and H2CO, for which a graphical mnemonic due to Cornwell is used to illustrate the effect of hyperconjugative delocalization on the carbon shielding.

Alpha particle backscattering measurements used for chemical analysis of surfaces

NASA Technical Reports Server (NTRS)

Patterson, J. H.

1967-01-01

Alpha particle backscattering performs a chemical analysis of surfaces. The apparatus uses a curium source and a semiconductor detector to determine the energy spectrum of the particles. This in turn determines the chemical composition of the surface after calibration to known samples.

Traits and causes of environmental loss-related chemical accidents in China based on co-word analysis.

PubMed

Wu, Desheng; Song, Yu; Xie, Kefan; Zhang, Baofeng

2018-04-25

Chemical accidents are major causes of environmental losses and have been debated due to the potential threat to human beings and environment. Compared with the single statistical analysis, co-word analysis of chemical accidents illustrates significant traits at various levels and presents data into a visual network. This study utilizes a co-word analysis of the keywords extracted from the Web crawling texts of environmental loss-related chemical accidents and uses the Pearson's correlation coefficient to examine the internal attributes. To visualize the keywords of the accidents, this study carries out a multidimensional scaling analysis applying PROXSCAL and centrality identification. The research results show that an enormous environmental cost is exacted, especially given the expected environmental loss-related chemical accidents with geographical features. Meanwhile, each event often brings more than one environmental impact. Large number of chemical substances are released in the form of solid, liquid, and gas, leading to serious results. Eight clusters that represent the traits of these accidents are formed, including "leakage," "poisoning," "explosion," "pipeline crack," "river pollution," "dust pollution," "emission," and "industrial effluent." "Explosion" and "gas" possess a strong correlation with "poisoning," located at the center of visualization map.

Multivariate Statistical Analysis of MSL APXS Bulk Geochemical Data

NASA Astrophysics Data System (ADS)

Hamilton, V. E.; Edwards, C. S.; Thompson, L. M.; Schmidt, M. E.

2014-12-01

We apply cluster and factor analyses to bulk chemical data of 130 soil and rock samples measured by the Alpha Particle X-ray Spectrometer (APXS) on the Mars Science Laboratory (MSL) rover Curiosity through sol 650. Multivariate approaches such as principal components analysis (PCA), cluster analysis, and factor analysis compliment more traditional approaches (e.g., Harker diagrams), with the advantage of simultaneously examining the relationships between multiple variables for large numbers of samples. Principal components analysis has been applied with success to APXS, Pancam, and Mössbauer data from the Mars Exploration Rovers. Factor analysis and cluster analysis have been applied with success to thermal infrared (TIR) spectral data of Mars. Cluster analyses group the input data by similarity, where there are a number of different methods for defining similarity (hierarchical, density, distribution, etc.). For example, without any assumptions about the chemical contributions of surface dust, preliminary hierarchical and K-means cluster analyses clearly distinguish the physically adjacent rock targets Windjana and Stephen as being distinctly different than lithologies observed prior to Curiosity's arrival at The Kimberley. In addition, they are separated from each other, consistent with chemical trends observed in variation diagrams but without requiring assumptions about chemical relationships. We will discuss the variation in cluster analysis results as a function of clustering method and pre-processing (e.g., log transformation, correction for dust cover) and implications for interpreting chemical data. Factor analysis shares some similarities with PCA, and examines the variability among observed components of a dataset so as to reveal variations attributable to unobserved components. Factor analysis has been used to extract the TIR spectra of components that are typically observed in mixtures and only rarely in isolation; there is the potential for similar results with data from APXS. These techniques offer new ways to understand the chemical relationships between the materials interrogated by Curiosity, and potentially their relation to materials observed by APXS instruments on other landed missions.

ARO - Terrestrial Research Program, Methodologies and Protocols for Characterization of Geomaterials

DTIC Science & Technology

2015-05-14

of ice involves melting, digestion, and analysis using inductively coupled plasma – mass spectrometry (ICPMS). ICP-MS analysis established elemental...4] have distinct chemical compositions. Knowledge of the chemical composition of the mineral assemblage present in a rock is critical to...activation analysis (INAA), to inductively-coupled plasma analysis and mass spectrometry (ICP & ICP-MS), mass spectrometry (MS), and laser-ablation

David Brandner | NREL

Science.gov Websites

chemical reaction engineering and transport phenomena Analytical analysis of complex bio-derived samples and Lignin Areas of Expertise Analytical analysis of complex samples Chemical reaction engineering and

Preliminary Problem Definition Study of 48 Munitions-Related Chemicals. Volume II. Propellant-Related Chemicals

DTIC Science & Technology

1978-04-01

34analysis of sediment and biota samples from Radford AAP aquatic toxicity studies if the literature evaluation reveals the need for more information... Sampling and analysis at Radford be performed to determine the quantity of the compound entering the New River Best Available Co. -7- V - A literature...chemical properties of this compound if they can not be obtained from the manufacturer - Sampling and analysis of sediment and biota at Radford AAP to

Comprehensive Mass Analysis for Chemical Processes, a Case Study on L-Dopa Manufacture

EPA Science Inventory

To evaluate the “greenness” of chemical processes in route selection and process development, we propose a comprehensive mass analysis to inform the stakeholders from different fields. This is carried out by characterizing the mass intensity for each contributing chemical or wast...

Some aspects of mathematical and chemical modeling of complex chemical processes

NASA Technical Reports Server (NTRS)

Nemes, I.; Botar, L.; Danoczy, E.; Vidoczy, T.; Gal, D.

1983-01-01

Some theoretical questions involved in the mathematical modeling of the kinetics of complex chemical process are discussed. The analysis is carried out for the homogeneous oxidation of ethylbenzene in the liquid phase. Particular attention is given to the determination of the general characteristics of chemical systems from an analysis of mathematical models developed on the basis of linear algebra.

Application of Graph Theory to Cost-Effective Fire Protection of Chemical Plants During Domino Effects.

PubMed

Khakzad, Nima; Landucci, Gabriele; Reniers, Genserik

2017-09-01

In the present study, we have introduced a methodology based on graph theory and multicriteria decision analysis for cost-effective fire protection of chemical plants subject to fire-induced domino effects. By modeling domino effects in chemical plants as a directed graph, the graph centrality measures such as out-closeness and betweenness scores can be used to identify the installations playing a key role in initiating and propagating potential domino effects. It is demonstrated that active fire protection of installations with the highest out-closeness score and passive fire protection of installations with the highest betweenness score are the most effective strategies for reducing the vulnerability of chemical plants to fire-induced domino effects. We have employed a dynamic graph analysis to investigate the impact of both the availability and the degradation of fire protection measures over time on the vulnerability of chemical plants. The results obtained from the graph analysis can further be prioritized using multicriteria decision analysis techniques such as the method of reference point to find the most cost-effective fire protection strategy. © 2016 Society for Risk Analysis.

Measurement of chromium VI and chromium III in stainless steel welding fumes with electrom spectroscopy for chemical analysis and neutron activation analysis.

PubMed

Lautner, G M; Carver, J C; Konzen, R B

1978-08-01

Electron Spectroscopy for Chemical Analysis (ESCA) was explored as a means of studying the oxidation state of chromium in SMAC (coated electrode) stainless steel welding fume collected on Nucleopore filters in the laboratory. Chromuim VI and III (as a percent of the total chromium) obtained from ESCA analysis was applied to results from Neutron Activation Analysis (NAA) to yield an average of 69 microgram chromium VI per sample. Diphenylcarbazide/atomic absorption (DPC/AA) results are reported for samples submitted to an industrial laboratory. Possible chemical species and solubility of chromium VI in stainless steel fumes is discussed in light of analogy between the SMAC process and the manufacturing process for chromates.

In-situ chemical imager

NASA Technical Reports Server (NTRS)

Kossakovski, D. A.; Bearman, G. H.; Kirschvink, J. L.

2000-01-01

A variety of in-situ planetary exploration tasks such as particulate analysis or life detection require a tool with a capability for combined imaging and chemical analysis with sub-micron spatial resolution.

Chemical preconcentrator

DOEpatents

Manginell, Ronald P.; Frye-Mason, Gregory C.

2001-01-01

A chemical preconcentrator is disclosed with applications to chemical sensing and analysis. The preconcentrator can be formed by depositing a resistive heating element (e.g. platinum) over a membrane (e.g. silicon nitride) suspended above a substrate. A coating of a sorptive material (e.g. a microporous hydrophobic sol-gel coating or a polymer coating) is formed on the suspended membrane proximate to the heating element to selective sorb one or more chemical species of interest over a time period, thereby concentrating the chemical species in the sorptive material. Upon heating the sorptive material with the resistive heating element, the sorbed chemical species are released for detection and analysis in a relatively high concentration and over a relatively short time period. The sorptive material can be made to selectively sorb particular chemical species of interest while not substantially sorbing other chemical species not of interest. The present invention has applications for use in forming high-sensitivity, rapid-response miniaturized chemical analysis systems (e.g. a "chem lab on a chip").

Pretest uncertainty analysis for chemical rocket engine tests

NASA Technical Reports Server (NTRS)

Davidian, Kenneth J.

1987-01-01

A parametric pretest uncertainty analysis has been performed for a chemical rocket engine test at a unique 1000:1 area ratio altitude test facility. Results from the parametric study provide the error limits required in order to maintain a maximum uncertainty of 1 percent on specific impulse. Equations used in the uncertainty analysis are presented.

Flow Injection Analysis and Liquid Chromatography for Multifunctional Chemical Analysis (MCA) Systems

ERIC Educational Resources Information Center

Mayo, Ana V.; Loegel, Thomas N.; Bretz, Stacey Lowery; Danielson, Neil D.

2013-01-01

The large class sizes of first-year chemistry labs makes it challenging to provide students with hands-on access to instrumentation because the number of students typically far exceeds the number of research-grade instruments available to collect data. Multifunctional chemical analysis (MCA) systems provide a viable alternative for large-scale…

National Standard Catalog (Selected Pages).

DTIC Science & Technology

1987-09-11

Sodium thiosulphate - Iodine content method for measuring copper B 223.19-82 Chemical analysis of 63. 12.31 82.7.9 e.4. 1 steel iron and alloy...82.6.21 83.3.1 st ibium; Using burning iodine content to determine sulphur GB 3253.7-82 Chemical analysis of 82.6.21 83.3.1 stibium; Using 3, 3’ - two...Standard ID Standard Name __ _ Year Month Day Using iodine content to determinate stibium oxide GB 3254.2-82 Chemical analysis of 82.6.21 83.3.1

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.

NETL - Thermogravimetric Analysis Laboratory

ScienceCinema

Richards, George

2018-06-22

Researchers in NETL's Thermal Analysis Laboratory are investigating chemical looping combustion. As a clean and efficient fossil fuel technology, chemical looping combustion controls CO2 emissions and offers a promising alternative to traditional combustion.

Determination of equilibrium structures of bromothymol blue revealed by using quantum chemistry with an aid of multivariate analysis of electronic absorption spectra

NASA Astrophysics Data System (ADS)

Shimada, Toru; Hasegawa, Takeshi

2017-10-01

The pH dependent chemical structures of bromothymol blue (BTB), which have long been under controversy, are determined by employing a combined technique of multivariate analysis of electronic absorption spectra and quantum chemistry. Principle component analysis (PCA) of the pH dependent spectra apparently reveals that only two chemical species are adequate to fully account for the color changes, with which the spectral decomposition is readily performed by using augmented alternative least-squares (ALS) regression analysis. The quantity variation by the ALS analysis also reveals the practical acid dissociation constant, pKa‧. The determination of pKa‧ is performed for various ionic strengths, which reveals the thermodynamic acid constant (pKa = 7.5) and the number of charge on each chemical species; the yellow form is negatively charged species of - 1 and the blue form that of - 2. On this chemical information, the quantum chemical calculation is carried out to find that BTB molecules take the pure quinoid form in an acid solution and the quinoid-phenolate form in an alkaline solution. The time-dependent density functional theory (TD-DFT) calculations for the theoretically determined chemical structures account for the peak shift of the electronic spectra. In this manner, the structures of all the chemical species appeared in equilibrium have finally been confirmed.

Determination of equilibrium structures of bromothymol blue revealed by using quantum chemistry with an aid of multivariate analysis of electronic absorption spectra.

PubMed

Shimada, Toru; Hasegawa, Takeshi

2017-10-05

The pH dependent chemical structures of bromothymol blue (BTB), which have long been under controversy, are determined by employing a combined technique of multivariate analysis of electronic absorption spectra and quantum chemistry. Principle component analysis (PCA) of the pH dependent spectra apparently reveals that only two chemical species are adequate to fully account for the color changes, with which the spectral decomposition is readily performed by using augmented alternative least-squares (ALS) regression analysis. The quantity variation by the ALS analysis also reveals the practical acid dissociation constant, pK a '. The determination of pK a ' is performed for various ionic strengths, which reveals the thermodynamic acid constant (pK a =7.5) and the number of charge on each chemical species; the yellow form is negatively charged species of -1 and the blue form that of -2. On this chemical information, the quantum chemical calculation is carried out to find that BTB molecules take the pure quinoid form in an acid solution and the quinoid-phenolate form in an alkaline solution. The time-dependent density functional theory (TD-DFT) calculations for the theoretically determined chemical structures account for the peak shift of the electronic spectra. In this manner, the structures of all the chemical species appeared in equilibrium have finally been confirmed. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of the chemical composition of Adenostemma lavenia (L.) Kuntze and Adenostemma platyphyllum Cass

NASA Astrophysics Data System (ADS)

Fauzan, A.; Praseptiangga, D.; Hartanto, R.; Pujiasmanto, B.

2018-01-01

The purpose of this study was to characterize the chemical compounds of Adenostemma lavenia (L.) Kuntze (Al) and Adenostemma platyphyllum Cass (Ap) using Pyrolysis-gas chromatography/mass spectrometry (Py-GCMS) and proximate analysis. Two species of Adenostemma samples (roots, stem and leaves) about 1 mg was pyrolyzed directly at the optimum temperature of 600°C. Py-GCMS was relatively fast, easy to use and without samples preparation and identification of the chemical compounds was carried out by comparison of the mass spectra obtained with those stored in Wiley 7th libraries. The data of proximate analysis were statistically analysed using Friedman test followed and hierarchical cluster analysis (HCA) for data of Py-GCMS. The result of proximate analysis showed that A. lavenia (L.) Kuntze (Al) and A. platyphyllum Cass (Ap) contained 8.27% (Al) and 9.18% (Ap) of water, 11.52% (Al) and 17.84% (Ap) of protein, 5.67% (Al) and 6.33% (Ap) of fat, and 17.32% (Al) and 19.94 (Ap) of ash. Amines, aldehydes, fatty acids, terpenoids-steroids, alkaloids, aromatic and aliphatic hydrocarbons, phenolic, and oligopeptides as part of 125 chemical compounds of each species are identified by Py-GCMS analysis. Hierarchical cluster analysis of pyrolysis products indicate not similitary of major chemical compounds of two Adenostemma species.

High resolution Physio-chemical Tissue Analysis: Towards Non-invasive In Vivo Biopsy

NASA Astrophysics Data System (ADS)

Xu, Guan; Meng, Zhuo-Xian; Lin, Jian-Die; Deng, Cheri X.; Carson, Paul L.; Fowlkes, J. Brian; Tao, Chao; Liu, Xiaojun; Wang, Xueding

2016-02-01

Conventional gold standard histopathologic diagnosis requires information of both high resolution structural and chemical changes in tissue. Providing optical information at ultrasonic resolution, photoacoustic (PA) technique could provide highly sensitive and highly accurate tissue characterization noninvasively in the authentic in vivo environment, offering a replacement for histopathology. A two-dimensional (2D) physio-chemical spectrogram (PCS) combining micrometer to centimeter morphology and chemical composition simultaneously can be generated for each biological sample with PA measurements at multiple optical wavelengths. This spectrogram presents a unique 2D “physio-chemical signature” for any specific type of tissue. Comprehensive analysis of PCS, termed PA physio-chemical analysis (PAPCA), can lead to very rich diagnostic information, including the contents of all relevant molecular and chemical components along with their corresponding histological microfeatures, comparable to those accessible by conventional histology. PAPCA could contribute to the diagnosis of many diseases involving diffusive patterns such as fatty liver.

Disturbance of Soil Organic Matter and Nitrogen Dynamics: Implications for Soil and Water Quality

DTIC Science & Technology

2004-06-30

Although we were unable to provide a precise chemical analysis of refractory soil carbon, it does appear to have the same chemical properties as... chemical analysis of this refractory carbon, but it has chemical properties similar to charcoal (Garten et al., 2003) and probably originates from...vegetation and forests at Fort Benning includes ≈10% refractory C that is chemically similar to charcoal (Garten and Ashwood, 2004) and probably has

A decision analysis framework for estimating the potential hazards for drinking water resources of chemicals used in hydraulic fracturing fluids.

PubMed

Yost, Erin E; Stanek, John; Burgoon, Lyle D

2017-01-01

Despite growing concerns over the potential for hydraulic fracturing to impact drinking water resources, there are limited data available to identify chemicals used in hydraulic fracturing fluids that may pose public health concerns. In an effort to explore these potential hazards, a multi-criteria decision analysis (MCDA) framework was employed to analyze and rank selected subsets of these chemicals by integrating data on toxicity, frequency of use, and physicochemical properties that describe transport in water. Data used in this analysis were obtained from publicly available databases compiled by the United States Environmental Protection Agency (EPA) as part of a larger study on the potential impacts of hydraulic fracturing on drinking water. Starting with nationwide hydraulic fracturing chemical usage data from EPA's analysis of the FracFocus Chemical Disclosure Registry 1.0, MCDAs were performed on chemicals that had either noncancer toxicity values (n=37) or cancer-specific toxicity values (n=10). The noncancer MCDA was then repeated for subsets of chemicals reported in three representative states (Texas, n=31; Pennsylvania, n=18; and North Dakota, n=20). Within each MCDA, chemicals received scores based on relative toxicity, relative frequency of use, and physicochemical properties (mobility in water, volatility, persistence). Results show a relative ranking of these chemicals based on hazard potential, and provide preliminary insight into chemicals that may be more likely than others to impact drinking water resources. Comparison of nationwide versus state-specific analyses indicates regional differences in the chemicals that may be of more concern to drinking water resources, although many chemicals were commonly used and received similar overall hazard rankings. Several chemicals highlighted by these MCDAs have been reported in groundwater near areas of hydraulic fracturing activity. This approach is intended as a preliminary analysis, and represents one possible method for integrating data to explore potential public health impacts. Published by Elsevier B.V.

Pretreatment and integrated analysis of spectral data reveal seaweed similarities based on chemical diversity.

PubMed

Wei, Feifei; Ito, Kengo; Sakata, Kenji; Date, Yasuhiro; Kikuchi, Jun

2015-03-03

Extracting useful information from high dimensionality and large data sets is a major challenge for data-driven approaches. The present study was aimed at developing novel integrated analytical strategies for comprehensively characterizing seaweed similarities based on chemical diversity. The chemical compositions of 107 seaweed and 2 seagrass samples were analyzed using multiple techniques, including Fourier transform infrared (FT-IR) and solid- and solution-state nuclear magnetic resonance (NMR) spectroscopy, thermogravimetry-differential thermal analysis (TG-DTA), inductively coupled plasma-optical emission spectrometry (ICP-OES), CHNS/O total elemental analysis, and isotope ratio mass spectrometry (IR-MS). The spectral data were preprocessed using non-negative matrix factorization (NMF) and NMF combined with multivariate curve resolution-alternating least-squares (MCR-ALS) methods in order to separate individual component information from the overlapping and/or broad spectral peaks. Integrated analysis of the preprocessed chemical data demonstrated distinct discrimination of differential seaweed species. Further network analysis revealed a close correlation between the heavy metal elements and characteristic components of brown algae, such as cellulose, alginic acid, and sulfated mucopolysaccharides, providing a componential basis for its metal-sorbing potential. These results suggest that this integrated analytical strategy is useful for extracting and identifying the chemical characteristics of diverse seaweeds based on large chemical data sets, particularly complicated overlapping spectral data.

Noninvasive deep Raman detection with 2D correlation analysis

NASA Astrophysics Data System (ADS)

Kim, Hyung Min; Park, Hyo Sun; Cho, Youngho; Jin, Seung Min; Lee, Kang Taek; Jung, Young Mee; Suh, Yung Doug

2014-07-01

The detection of poisonous chemicals enclosed in daily necessaries is prerequisite essential for homeland security with the increasing threat of terrorism. For the detection of toxic chemicals, we combined a sensitive deep Raman spectroscopic method with 2D correlation analysis. We obtained the Raman spectra from concealed chemicals employing spatially offset Raman spectroscopy in which incident line-shaped light experiences multiple scatterings before being delivered to inner component and yielding deep Raman signal. Furthermore, we restored the pure Raman spectrum of each component using 2D correlation spectroscopic analysis with chemical inspection. Using this method, we could elucidate subsurface component under thick powder and packed contents in a bottle.

Thermodynamic and themoeconomic optimization of isothermal endoreversible chemical engine models

NASA Astrophysics Data System (ADS)

Ocampo-García, A.; Barranco-Jiménez, M. A.; Angulo-Brown, F.

2017-12-01

A branch of finite-time thermodynamics (FTT) is the thermoeconomical analysis of simplified power plant models. The most studied models are those of the Curzon-Ahlborn (CA) and Novikov-Chambadal types. In the decade of 90's of the past century, the FTT analysis of thermal engines was extended to chemical engines. In the present paper we made a thermoeconomical analysis of heat engines and chemical engines of the CA and Novikov types. This study is carried out for isothermal endoreversible chemical engine models with a linear mass transfer law and under three different modes of thermodynamic performance (maximum power, maximum ecological function and maximum efficient power).

Extracting chemical information from high-resolution Kβ X-ray emission spectroscopy

NASA Astrophysics Data System (ADS)

Limandri, S.; Robledo, J.; Tirao, G.

2018-06-01

High-resolution X-ray emission spectroscopy allows studying the chemical environment of a wide variety of materials. Chemical information can be obtained by fitting the X-ray spectra and observing the behavior of some spectral features. Spectral changes can also be quantified by means of statistical parameters calculated by considering the spectrum as a probability distribution. Another possibility is to perform statistical multivariate analysis, such as principal component analysis. In this work the performance of these procedures for extracting chemical information in X-ray emission spectroscopy spectra for mixtures of Mn2+ and Mn4+ oxides are studied. A detail analysis of the parameters obtained, as well as the associated uncertainties is shown. The methodologies are also applied for Mn oxidation state characterization of double perovskite oxides Ba1+xLa1-xMnSbO6 (with 0 ≤ x ≤ 0.7). The results show that statistical parameters and multivariate analysis are the most suitable for the analysis of this kind of spectra.

Mass Spectrometry in Organic Synthesis: Claisen-Schmidt Base-Catalyzed Condensation and Hammett Correlation of Substituent Effects

ERIC Educational Resources Information Center

Bain, Ryan M.; Pulliam, Christopher J.; Yan, Xin; Moore, Kassandra F.; Mu¨ller, Thomas; Cooks, R. Graham

2014-01-01

Undergraduate laboratories generally teach an understanding of chemical reactivity using bulk or semimicroscale experiments with product isolation and subsequent chemical and spectroscopic analysis. In this study students were exposed to mass spectrometry as a means of chemical synthesis as well as analysis. The ionization method used, paper…

Correction to: Top Down Tandem Mass Spectrometric Analysis of a Chemically Modified Rough-Type Lipopolysaccharide Vaccine Candidate

NASA Astrophysics Data System (ADS)

Oyler, Benjamin L.; Khan, Mohd M.; Smith, Donald F.; Harberts, Erin M.; Kilgour, David P. A.; Ernst, Robert K.; Cross, Alan S.; Goodlett, David R.

2018-04-01

In the preceding article "Top Down Tandem Mass Spectrometric Analysis of a Chemically Modified Rough-Type Lipopolysaccharide Vaccine Candidate" by Oyler et al., an error in the J5 E. coli LPS chemical structure (Figs. 2 and 4) was introduced and propagated into the final revision.

Diagnostic Chemical Analysis of Exhaled Human Breath Using a Novel Sub-Millimeter Spectroscopic Approach

NASA Astrophysics Data System (ADS)

Fosnight, Alyssa M.; Moran, Benjamin L.; Branco, Daniela R.; Thomas, Jessica R.; Medvedev, Ivan R.

2013-06-01

As many as 3000 chemicals are reported to be found in exhaled human breath. Many of these chemicals are linked to certain health conditions and environmental exposures. Present state of the art techniques used for analysis of exhaled human breath include mass spectrometry based methods, infrared spectroscopic sensors, electro chemical sensors and semiconductor oxide based testers. Some of these techniques are commercially available but are somewhat limited in their specificity and exhibit fairly high probability of false alarm. Here, we present the results of our most recent study which demonstrated a novel application of a terahertz high resolutions spectroscopic technique to the analysis of exhaled human breath, focused on detection of ethanol in the exhaled breath of a person which consumed an alcoholic drink. This technique possesses nearly ``absolute'' specificity and we demonstrated its ability to uniquely identify ethanol, methanol, and acetone in human breath. This project is now complete and we are looking to extend this method of chemical analysis of exhaled human breath to a broader range of chemicals in an attempt to demonstrate its potential for biomedical diagnostic purposes.

SWOT analysis for safer carriage of bulk liquid chemicals in tankers.

PubMed

Arslan, Ozcan; Er, Ismail Deha

2008-06-15

The application of strengths, weaknesses, opportunities and threats (SWOT) analysis to formulation of strategy concerned with the safe carriage of bulk liquid chemicals in maritime tankers was examined in this study. A qualitative investigation using SWOT analysis has been implemented successfully for ships that are designed to carry liquid chemicals in bulk. The originality of this study lies in the use of SWOT analysis as a management tool to formulate strategic action plans for ship management companies, ship masters and officers for the carriage of dangerous goods in bulk. With this transportation-based SWOT analysis, efforts were made to explore the ways and means of converting possible threats into opportunities, and changing weaknesses into strengths; and strategic plans of action were developed for safer tanker operation.

Risk Analysis of a Fuel Storage Terminal Using HAZOP and FTA

PubMed Central

Baixauli-Pérez, Mª Piedad

2017-01-01

The size and complexity of industrial chemical plants, together with the nature of the products handled, means that an analysis and control of the risks involved is required. This paper presents a methodology for risk analysis in chemical and allied industries that is based on a combination of HAZard and OPerability analysis (HAZOP) and a quantitative analysis of the most relevant risks through the development of fault trees, fault tree analysis (FTA). Results from FTA allow prioritizing the preventive and corrective measures to minimize the probability of failure. An analysis of a case study is performed; it consists in the terminal for unloading chemical and petroleum products, and the fuel storage facilities of two companies, in the port of Valencia (Spain). HAZOP analysis shows that loading and unloading areas are the most sensitive areas of the plant and where the most significant danger is a fuel spill. FTA analysis indicates that the most likely event is a fuel spill in tank truck loading area. A sensitivity analysis from the FTA results show the importance of the human factor in all sequences of the possible accidents, so it should be mandatory to improve the training of the staff of the plants. PMID:28665325

Risk Analysis of a Fuel Storage Terminal Using HAZOP and FTA.

PubMed

Fuentes-Bargues, José Luis; González-Cruz, Mª Carmen; González-Gaya, Cristina; Baixauli-Pérez, Mª Piedad

2017-06-30

The size and complexity of industrial chemical plants, together with the nature of the products handled, means that an analysis and control of the risks involved is required. This paper presents a methodology for risk analysis in chemical and allied industries that is based on a combination of HAZard and OPerability analysis (HAZOP) and a quantitative analysis of the most relevant risks through the development of fault trees, fault tree analysis (FTA). Results from FTA allow prioritizing the preventive and corrective measures to minimize the probability of failure. An analysis of a case study is performed; it consists in the terminal for unloading chemical and petroleum products, and the fuel storage facilities of two companies, in the port of Valencia (Spain). HAZOP analysis shows that loading and unloading areas are the most sensitive areas of the plant and where the most significant danger is a fuel spill. FTA analysis indicates that the most likely event is a fuel spill in tank truck loading area. A sensitivity analysis from the FTA results show the importance of the human factor in all sequences of the possible accidents, so it should be mandatory to improve the training of the staff of the plants.

Applying network analysis and Nebula (neighbor-edges based and unbiased leverage algorithm) to ToxCast data.

PubMed

Ye, Hao; Luo, Heng; Ng, Hui Wen; Meehan, Joe; Ge, Weigong; Tong, Weida; Hong, Huixiao

2016-01-01

ToxCast data have been used to develop models for predicting in vivo toxicity. To predict the in vivo toxicity of a new chemical using a ToxCast data based model, its ToxCast bioactivity data are needed but not normally available. The capability of predicting ToxCast bioactivity data is necessary to fully utilize ToxCast data in the risk assessment of chemicals. We aimed to understand and elucidate the relationships between the chemicals and bioactivity data of the assays in ToxCast and to develop a network analysis based method for predicting ToxCast bioactivity data. We conducted modularity analysis on a quantitative network constructed from ToxCast data to explore the relationships between the assays and chemicals. We further developed Nebula (neighbor-edges based and unbiased leverage algorithm) for predicting ToxCast bioactivity data. Modularity analysis on the network constructed from ToxCast data yielded seven modules. Assays and chemicals in the seven modules were distinct. Leave-one-out cross-validation yielded a Q(2) of 0.5416, indicating ToxCast bioactivity data can be predicted by Nebula. Prediction domain analysis showed some types of ToxCast assay data could be more reliably predicted by Nebula than others. Network analysis is a promising approach to understand ToxCast data. Nebula is an effective algorithm for predicting ToxCast bioactivity data, helping fully utilize ToxCast data in the risk assessment of chemicals. Published by Elsevier Ltd.

[Correspondence analysis between traditional commercial specifications and quantitative quality indices of Notopterygii Rhizoma et Radix].

PubMed

Jiang, Shun-Yuan; Sun, Hong-Bing; Sun, Hui; Ma, Yu-Ying; Chen, Hong-Yu; Zhu, Wen-Tao; Zhou, Yi

2016-03-01

This paper aims to explore a comprehensive assessment method combined traditional Chinese medicinal material specifications with quantitative quality indicators. Seventy-six samples of Notopterygii Rhizoma et Radix were collected on market and at producing areas. Traditional commercial specifications were described and assigned, and 10 chemical components and volatile oils were determined for each sample. Cluster analysis, Fisher discriminant analysis and correspondence analysis were used to establish the relationship between the traditional qualitative commercial specifications and quantitative chemical indices for comprehensive evaluating quality of medicinal materials, and quantitative classification of commercial grade and quality grade. A herb quality index (HQI) including traditional commercial specifications and chemical components for quantitative grade classification were established, and corresponding discriminant function were figured out for precise determination of quality grade and sub-grade of Notopterygii Rhizoma et Radix. The result showed that notopterol, isoimperatorin and volatile oil were the major components for determination of chemical quality, and their dividing values were specified for every grade and sub-grade of the commercial materials of Notopterygii Rhizoma et Radix. According to the result, essential relationship between traditional medicinal indicators, qualitative commercial specifications, and quantitative chemical composition indicators can be examined by K-mean cluster, Fisher discriminant analysis and correspondence analysis, which provide a new method for comprehensive quantitative evaluation of traditional Chinese medicine quality integrated traditional commodity specifications and quantitative modern chemical index. Copyright© by the Chinese Pharmaceutical Association.

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

Kaygusuz, K.

Exergy analysis is a general method for efficiency analysis of systems and processes. The use of the exergy concept and the analysis of ultimate efficiencies of processes is more or less still limited to the academic world. There are several reasons why its industrial use is still limited. To overcome some of the difficulties in industrial applications of energy analysis, it has made use of exergy analysis. The chemical exergy of a substance is the maximum work that can be obtained from it by taking it to chemical equilibrium with the reference environment at a constant temperature and pressure. Themore » first law analysis gives only the quantity of energy, while the second law defines the quality of energy also. The projected increase in coal utilization in power plants makes it desirable to evaluate the energy content of coal both quantitatively and qualitatively. In the present study, the chemical exergies of some coals of good quality in Turkey were calculated with the BASIC program by using second law analysis and the results were given as tabulated.« less

Low-thrust chemical propulsion system propellant expulsion and thermal conditioning study. Executive summary

NASA Technical Reports Server (NTRS)

Merino, F.; Wakabayashi, I.; Pleasant, R. L.; Hill, M.

1982-01-01

Preferred techniques for providing abort pressurization and engine feed system net positive suction pressure (NPSP) for low thrust chemical propulsion systems (LTPS) were determined. A representative LTPS vehicle configuration is presented. Analysis tasks include: propellant heating analysis; pressurant requirements for abort propellant dump; and comparative analysis of pressurization techniques and thermal subcoolers.

A Laboratory Classroom Where ?Wining? Is Encouraged

ERIC Educational Resources Information Center

Gibbs, Hope

2004-01-01

A wine analysis for most is: take a sip, and either like it or don't. Not so for the students taking wine analysis courses at California Polytechnic State University in San Luis Obispo, California. In the college's new Wine Analysis Laboratory, students learn how to run chemical analyses of wines and compare chemical profiles of wines. Professor…

Device and method for enhanced collection and assay of chemicals with high surface area ceramic

DOEpatents

Addleman, Raymond S.; Li, Xiaohong Shari; Chouyyok, Wilaiwan; Cinson, Anthony D.; Bays, John T.; Wallace, Krys

2016-02-16

A method and device for enhanced capture of target analytes is disclosed. This invention relates to collection of chemicals for separations and analysis. More specifically, this invention relates to a solid phase microextraction (SPME) device having better capability for chemical collection and analysis. This includes better physical stability, capacity for chemical collection, flexible surface chemistry and high affinity for target analyte.

TOF-SIMS imaging technique with information entropy

NASA Astrophysics Data System (ADS)

Aoyagi, Satoka; Kawashima, Y.; Kudo, Masahiro

2005-05-01

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is capable of chemical imaging of proteins on insulated samples in principal. However, selection of specific peaks related to a particular protein, which are necessary for chemical imaging, out of numerous candidates had been difficult without an appropriate spectrum analysis technique. Therefore multivariate analysis techniques, such as principal component analysis (PCA), and analysis with mutual information defined by information theory, have been applied to interpret SIMS spectra of protein samples. In this study mutual information was applied to select specific peaks related to proteins in order to obtain chemical images. Proteins on insulated materials were measured with TOF-SIMS and then SIMS spectra were analyzed by means of the analysis method based on the comparison using mutual information. Chemical mapping of each protein was obtained using specific peaks related to each protein selected based on values of mutual information. The results of TOF-SIMS images of proteins on the materials provide some useful information on properties of protein adsorption, optimality of immobilization processes and reaction between proteins. Thus chemical images of proteins by TOF-SIMS contribute to understand interactions between material surfaces and proteins and to develop sophisticated biomaterials.

Analysis of the Precursors, Simulants and Degradation Products of Chemical Warfare Agents.

PubMed

Witkiewicz, Zygfryd; Neffe, Slawomir; Sliwka, Ewa; Quagliano, Javier

2018-09-03

Recent advances in analysis of precursors, simulants and degradation products of chemical warfare agents (CWA) are reviewed. Fast and reliable analysis of precursors, simulants and CWA degradation products is extremely important at a time, when more and more terrorist groups and radical non-state organizations use or plan to use chemical weapons to achieve their own psychological, political and military goals. The review covers the open source literature analysis after the time, when the chemical weapons convention had come into force (1997). The authors stated that during last 15 years increased number of laboratories are focused not only on trace analysis of CWA (mostly nerve and blister agents) in environmental and biological samples, but the growing number of research are devoted to instrumental analysis of precursors and degradation products of these substances. The identification of low-level concentration of CWA degradation products is often more important and difficult than the original CWA, because of lower level of concentration and a very large number of compounds present in environmental and biological samples. Many of them are hydrolysis products and are present in samples in the ionic form. For this reason, two or three instrumental methods are used to perform a reliable analysis of these substances.

Lessons learned from non-medical industries: root cause analysis as culture change at a chemical plant

PubMed Central

Carroll, J; Rudolph, J; Hatakenaka, S

2002-01-01



 Root cause analysis was introduced to a chemical plant as a way of enhancing performance and safety, exemplified by the investigation of an explosion. The cultural legacy of the root cause learning intervention was embodied in managers' increased openness to new ideas, individuals' questioning attitude and disciplined thinking, and a root cause analysis process that provided continual opportunities to learn and improve. Lessons for health care are discussed, taking account of differences between the chemical and healthcare industries. PMID:12486993

Chemical Analysis of Plants that Poison Livestock: Successes, Challenges, and Opportunities.

PubMed

Welch, Kevin D; Lee, Stephen T; Cook, Daniel; Gardner, Dale R; Pfister, James A

2018-04-04

Poisonous plants have a devastating impact on the livestock industry as well as human health. To fully understand the effects of poisonous plants, multiple scientific disciplines are required. Chemical analysis of plant secondary compounds is key to identifying the responsible toxins, characterizing their metabolism, and understanding their effects on animals and humans. In this review, we highlight some of the successes in studying poisonous plants and mitigating their toxic effects. We also highlight some of the remaining challenges and opportunities with regards to the chemical analysis of poisonous plants.

Chemical Analysis of the Moon at the Surveyor VII Landing Site: Preliminary Results.

PubMed

Turkevich, A L; Franzgrote, E J; Patterson, J H

1968-10-04

The alpha-scattering experiment aboard Surveyor VII has provided a chemical analysis of the moon in the area of the crater Tycho. The preliminary results indicate a chemical composition similar to that already found at two mare sites, but with a lower concentration of elements of the iron group (titanium through copper).

In-field volatile collection and analysis method utilizing a portable GC-MS: in situ headspace analysis of intact and damaged yellow starthistle flower heads

USDA-ARS?s Scientific Manuscript database

Introduction: Understanding the complex chemical signaling of plants and insects is an important component of chemical ecology. Accordingly, the collection of chemical cues from plants in their normal environment is integral to elucidation of multifaceted plant-insect communications. Often times rem...

Modern data science for analytical chemical data - A comprehensive review.

PubMed

Szymańska, Ewa

2018-10-22

Efficient and reliable analysis of chemical analytical data is a great challenge due to the increase in data size, variety and velocity. New methodologies, approaches and methods are being proposed not only by chemometrics but also by other data scientific communities to extract relevant information from big datasets and provide their value to different applications. Besides common goal of big data analysis, different perspectives and terms on big data are being discussed in scientific literature and public media. The aim of this comprehensive review is to present common trends in the analysis of chemical analytical data across different data scientific fields together with their data type-specific and generic challenges. Firstly, common data science terms used in different data scientific fields are summarized and discussed. Secondly, systematic methodologies to plan and run big data analysis projects are presented together with their steps. Moreover, different analysis aspects like assessing data quality, selecting data pre-processing strategies, data visualization and model validation are considered in more detail. Finally, an overview of standard and new data analysis methods is provided and their suitability for big analytical chemical datasets shortly discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

Laser applications to chemical, security, and environmental analysis: introduction to the feature issue.

PubMed

Seeger, Thomas; Dreier, Thomas; Chen, Weidong; Kearny, Sean; Kulatilaka, Waruna

2017-04-10

This Applied Optics feature issue on laser applications to chemical, security, and environmental analysis (LACSEA) highlights papers presented at the LACSEA 2016 Fifteenth Topical Meeting sponsored by the Optical Society of America.

EPA Analysis of FracFocus 1 Data

EPA Pesticide Factsheets

The EPA conducted an analysis to better understand the chemicals and water used to hydraulically fracture oil and gas production wells in the United States and how chemical and water use vary in different locations across the country.

Research Update: Spatially resolved mapping of electronic structure on atomic level by multivariate statistical analysis

NASA Astrophysics Data System (ADS)

Belianinov, Alex; Ganesh, Panchapakesan; Lin, Wenzhi; Sales, Brian C.; Sefat, Athena S.; Jesse, Stephen; Pan, Minghu; Kalinin, Sergei V.

2014-12-01

Atomic level spatial variability of electronic structure in Fe-based superconductor FeTe0.55Se0.45 (Tc = 15 K) is explored using current-imaging tunneling-spectroscopy. Multivariate statistical analysis of the data differentiates regions of dissimilar electronic behavior that can be identified with the segregation of chalcogen atoms, as well as boundaries between terminations and near neighbor interactions. Subsequent clustering analysis allows identification of the spatial localization of these dissimilar regions. Similar statistical analysis of modeled calculated density of states of chemically inhomogeneous FeTe1-xSex structures further confirms that the two types of chalcogens, i.e., Te and Se, can be identified by their electronic signature and differentiated by their local chemical environment. This approach allows detailed chemical discrimination of the scanning tunneling microscopy data including separation of atomic identities, proximity, and local configuration effects and can be universally applicable to chemically and electronically inhomogeneous surfaces.

Surface characterization and chemical analysis of bamboo substrates pretreated by alkali hydrogen peroxide.

PubMed

Song, Xueping; Jiang, Yan; Rong, Xianjian; Wei, Wei; Wang, Shuangfei; Nie, Shuangxi

2016-09-01

The surface characterization and chemical analysis of bamboo substrates by alkali hydrogen peroxide pretreatment (AHPP) were investigated in this study. The results tended to manifest that AHPP prior to enzymatic and chemical treatment was potential for improving accessibility and reactivity of bamboo substrates. The inorganic components, organic solvent extractives and acid-soluble lignin were effectively removed by AHPP. X-ray photoelectron spectroscopy (XPS) analysis indicated that the surface of bamboo chips had less lignin but more carbohydrate after pre-treatment. Fiber surfaces became etched and collapsed, and more pores and debris on the substrate surface were observed with Scanning Electron Microscopy (SEM). Brenauer-Emmett-Teller (BET) results showed that both of pore volume and surface area were increased after AHPP. Although XRD analysis showed that AHPP led to relatively higher crystallinity, pre-extraction could overall enhance the accessibility of enzymes and chemicals into the bamboo structure. Copyright © 2016. Published by Elsevier Ltd.

Toxicological analysis of formalin-fixed or embalmed tissues: a review.

PubMed

Nikolaou, Panagiota; Papoutsis, Ioannis; Dona, Artemisia; Spiliopoulou, Chara; Athanaselis, Sotiris

2013-12-10

During the autopsy of forensic cases, when there is no suspicion of drug use or chemical exposure, biological fluids may not be obtained for toxicological analysis, while specimens of tissues may be collected and preserved in a formalin solution for histological examination. When specific questions arise after the burial, the only possible options are the exhumation of an embalmed body or the toxicological analysis of the formalin-fixed specimens. The drug concentrations in these specimens can be altered due to the extraction efficiency and/or the chemical activity of the formalin solutions used during chemical fixation or embalming process. The aim of this paper is to review the published studies about the determination of specific groups of drugs in formalin-fixed or embalmed specimens and their stability after chemical fixation or embalming process. The analytical aspects of this determination are also discussed. The stability of drugs in formalin environment and the possible reaction of the drugs with formaldehyde, which is a highly reactive chemical substance, should always be considered during post-mortem/post-embalming forensic analysis. The additional analysis of the formalin solution in which the tissue was preserved is considered necessary. The identification and the evaluation of the possible degradation products or chemical derivatives are extremely useful during the interpretation of the results. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

[Spatial distribution characteristics of the physical and chemical properties of water in the Kunes River after the supply of snowmelt during spring].

PubMed

Liu, Xiang; Guo, Ling-Peng; Zhang, Fei-Yun; Ma, Jie; Mu, Shu-Yong; Zhao, Xin; Li, Lan-Hai

2015-02-01

Eight physical and chemical indicators related to water quality were monitored from nineteen sampling sites along the Kunes River at the end of snowmelt season in spring. To investigate the spatial distribution characteristics of water physical and chemical properties, cluster analysis (CA), discriminant analysis (DA) and principal component analysis (PCA) are employed. The result of cluster analysis showed that the Kunes River could be divided into three reaches according to the similarities of water physical and chemical properties among sampling sites, representing the upstream, midstream and downstream of the river, respectively; The result of discriminant analysis demonstrated that the reliability of such a classification was high, and DO, Cl- and BOD5 were the significant indexes leading to this classification; Three principal components were extracted on the basis of the principal component analysis, in which accumulative variance contribution could reach 86.90%. The result of principal component analysis also indicated that water physical and chemical properties were mostly affected by EC, ORP, NO3(-) -N, NH4(+) -N, Cl- and BOD5. The sorted results of principal component scores in each sampling sites showed that the water quality was mainly influenced by DO in upstream, by pH in midstream, and by the rest of indicators in downstream. The order of comprehensive scores for principal components revealed that the water quality degraded from the upstream to downstream, i.e., the upstream had the best water quality, followed by the midstream, while the water quality at downstream was the worst. This result corresponded exactly to the three reaches classified using cluster analysis. Anthropogenic activity and the accumulation of pollutants along the river were probably the main reasons leading to this spatial difference.

Risk Analysis in Support of the Chemical Stockpile Disposal Program. Volume 1. Analysis

DTIC Science & Technology

1987-12-17

Analysis of Event Probability A-14 A.4.2 Analysis of Event Consequence A-14 A.4.2.1 Agent Release to Atmosphere A-14 A.4.2.2 Toxic P-lume Size A-16 A...Disposal Program (CSDP), which comprises several alternatives for carrying out the disposal effort (U.S. Army Toxic and Hazardous Materials Agency, 1986...or unavoidable accident or event could occur that would expose a nearby civilian population to these toxic chemicals. Such events could occur even

Analysis of medium-BTU gasification condensates, June 1985-June 1986

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

Elliott, D.C.

1987-05-01

This report provides the final results of chemical and physical analysis of condensates from biomass gasification systems which are part of the US Department of Energy Biomass Thermochemical Conversion Program. The work described in detail in this report involves extensive analysis of condensates from four medium-BTU gasifiers. The analyses include elemental analysis, ash, moisture, heating value, density, specific chemical analysis, ash, moisture, heating value, density, specific chemical analysis (gas chromatography/mass spectrometry, infrared spectrophotometry, Carbon-13 nuclear magnetic resonance spectrometry) and Ames Assay. This work was an extension of a broader study earlier completed of the condensates of all the gasifers andmore » pyrolyzers in the Biomass Thermochemical Conversion Program. The analytical data demonstrates the wide range of chemical composition of the organics recoverd in the condensates and suggests a direct relationship between operating temperature and chemical composition of the condensates. A continuous pathway of thermal degradation of the tar components as a function of temperature is proposed. Variations in the chemical composition of the organic in the tars are reflected in the physical properties of tars and phase stability in relation to water in the condensate. The biological activity appears to be limited to the tars produced at high temperatures as a result of formation of polycyclic aromatic hydrocarbons in high concentrations. Future studies of the time/temperature relationship to tar composition and the effect of processing atmosphere should be undertaken. Further processing of the condensates either as wastewater treatment or upgrading of the organics to useful products is also recommended. 15 refs., 4 figs., 4 tabs.« less

Effect-based assessment of persistent organic pollutant and pesticide dumpsite using mammalian CALUX reporter cell lines.

PubMed

Pieterse, B; Rijk, I J C; Simon, E; van Vugt-Lussenburg, B M A; Fokke, B F H; van der Wijk, M; Besselink, H; Weber, R; van der Burg, B

2015-10-01

A combined chemical and biological analysis of samples from a major obsolete pesticide and persistent organic pollutant (POP) dumpsite in Northern Tajikistan was carried out. The chemical analytical screening focused on a range of prioritized compounds and compounds known to be present locally. Since chemical analytics does not allow measurements of hazards in complex mixtures, we tested the use of a novel effect-based approach using a panel of quantitative high-throughput CALUX reporter assays measuring distinct biological effects relevant in hazard assessment. Assays were included for assessing effects related to estrogen, androgen, and progestin signaling, aryl hydrocarbon receptor-mediated signaling, AP1 signaling, genotoxicity, oxidative stress, chemical hypoxia, and ER stress. With this panel of assays, we first quantified the biological activities of the individual chemicals measured in chemical analytics. Next, we calculated the expected sum activity by these chemicals in the samples of the pesticide dump site and compared the results with the measured CALUX bioactivity of the total extracts of these samples. The results showed that particularly endocrine disruption-related effects were common among the samples. This was consistent with the toxicological profiles of the individual chemicals that dominated these samples. However, large discrepancies between chemical and biological analysis were found in a sample from a burn place present in this site, with biological activities that could not be explained by chemical analysis. This is likely to be caused by toxic combustion products or by spills of compounds that were not targeted in the chemical analysis.

AN ADVANCED SYSTEM FOR POLLUTION PREVENTION IN CHEMICAL COMPLEXES

EPA Science Inventory

One important accomplishment is that the system will give process engineers interactively and simultaneously use of programs for total cost analysis, life cycle assessment and sustainability metrics to provide direction for the optimal chemical complex analysis pro...

Analysis of the temperature and pressure dependence of the 129Xe NMR chemical shift and signal intensity for the derivation of basic parameters of adsorption as applied to zeolite ZSM-5.

PubMed

Kawata, Yoko; Adachi, Yuko; Haga, Saori; Fukutomi, Junko; Imai, Hirohiko; Kimura, Atsuomi; Fujiwara, Hideaki

2007-12-01

Temperature and pressure dependences of the 129Xe NMR chemical shift and the signal intensity have been investigated using ZSM-5 as an adsorbent under routine conditions without using any high-pressure or especially high-temperature facilities. The use of a rigorously shielded system and a calibration sample for the signal intensity was found to be valuable to obtain reliable data about the chemical shift and the signal intensity. The 129Xe NMR data obtained between 0.05 and 1.5 atm and from 24 to 80 degrees C were analyzed based on the Dubinin-Radushkevich equation as well as the Langmuir type equation. In both analyses, chemical shift data succeeded only partially in providing the profile of adsorption, such as energetic aspects, surface area, saturated amount of Xe adsorption and specific parameters of 129Xe chemical shift. It was shown that the reliable total analysis was achieved when the chemical shift data were used together with the intensity data. Such an analysis of the chemical shift data, aided by the intensity data, will be useful in performing nano-material analysis on 129Xe NMR without invoking the traditional methodology of gravimetric or volumetric adsorption experiments.

Exploring the Potential for Using Inexpensive Natural Reagents Extracted from Plants to Teach Chemical Analysis

ERIC Educational Resources Information Center

Hartwell, Supaporn Kradtap

2012-01-01

A number of scientific articles report on the use of natural extracts from plants as chemical reagents, where the main objective is to present the scientific applications of those natural plant extracts. The author suggests that natural reagents extracted from plants can be used as alternative low cost tools in teaching chemical analysis,…

Environmental analysis of the chemical release module. [space shuttle payload

NASA Technical Reports Server (NTRS)

Heppner, J. P.; Dubin, M.

1980-01-01

The environmental analysis of the Chemical Release Module (a free flying spacecraft deployed from the space shuttle to perform chemical release experiments) is reviewed. Considerations of possible effects of the injectants on human health, ionosphere, weather, ground based optical astronomical observations, and satellite operations are included. It is concluded that no deleterious environmental effects of widespread or long lasting nature are anticipated from chemical releases in the upper atmosphere of the type indicated for the program.

Composition and properties of the so-called 'diamond-like' amorphous carbon films

NASA Technical Reports Server (NTRS)

Angus, J. C.; Stultz, J. E.; Shiller, P. J.; Macdonald, J. R.; Mirtich, M. J.

1984-01-01

The composition of amorphous 'diamond-like' films made by direct low energy ion beam deposition, R.F. discharge and sputtering was determined by nuclear reaction analysis, IR spectroscopy and microcombustion chemical analysis. The nuclear reaction analysis showed very similar hydrogen depth profiles for all three types of samples. The atomic ratio of hydrogen to carbon was approximately 0.2 at the film surface and rose to approximately 1.0 at a depth of 500 A. The integrated intensity of the C-H stretching band at about 2900 per cm indicates that the amount of chemically bonded hydrogen is less than the total hydrogen content. Combustion analysis confirmed the overall atomic ratio of hydrogen to carbon determined by nuclear reaction analysis. The chemical state of the non-bonded hydrogen was not determined; however, the effective diffusion coefficient computed from the hydrogen depth profile was extremely low. This indicates either that the films are exceedingly impermeable or that the non-bonded hydrogen requires an additional activated step to leave the films, e.g., desorption or chemical reaction.

Demonstration and Evaluation of Solid Phase Microextraction for the Assessment of Bioavailability and Contaminant Mobility (User’s Manual)

DTIC Science & Technology

2012-05-01

with HPLC and PCBs with GC-ECD. Details of the chemical analysis are not included in this description but standard methods are referenced. Other...5 4.4 Analysis of samples to get the accumulated uptake in the fiber ...................................... 8 4.5 Determination of pore water...13 5.5 QC samples for chemical analysis

Formalin preservation of avian blood for organochlorine analysis

USGS Publications Warehouse

Stafford, C.J.; Stickel, W.H.; Lamb, D.W.; Kenaga, E.E.

1981-01-01

Blood biopsy for chemical analysis is a valuable technique for evaluating chemical exposure of birds in the wild without harming the birds. Field conditions, however, often make sample storage difficult. Better methods than freezing are needed to improve the interpretive value of chemical analysis of the sample. The use of formalin was explored for this purpose. A pooled sample of blood containing naturally incorporated 1,1-bis-(p-chlorophenyl)-2,2,2-trichloroethane (DDT), 2,2-bis-(p-chlorophenyl)1,1 dichloroethylene (DDE), and dieldrin was subdivided into 30 samples, of which 10 were frozen, 10 more were kept at room temperature, and 10 were formalinized by adding I part of chemically pure formalin to 20 parts of blood. The formalinized samples yielded the highest and least variable concentrations of chemicals. The field procedures are outlined.

Integrated Proteomic Approaches for Understanding Toxicity of Environmental Chemicals

EPA Science Inventory

To apply quantitative proteomic analysis to the evaluation of toxicity of environmental chemicals, we have developed an integrated proteomic technology platform. This platform has been applied to the analysis of the toxic effects and pathways of many important environmental chemi...

Analysis of river pollution data from low-flow period by means of multivariate techniques: a case study from the oil-shale industry region, northeastern Estonia.

PubMed

Truu, Jaak; Heinaru, Eeva; Talpsep, Ene; Heinaru, Ain

2002-01-01

The oil-shale industry has created serious pollution problems in northeastern Estonia. Untreated, phenol-rich leachate from semi-coke mounds formed as a by-product of oil-shale processing is discharged into the Baltic Sea via channels and rivers. An exploratory analysis of water chemical and microbiological data sets from the low-flow period was carried out using different multivariate analysis techniques. Principal component analysis allowed us to distinguish different locations in the river system. The riverine microbial community response to water chemical parameters was assessed by co-inertia analysis. Water pH, COD and total nitrogen were negatively related to the number of biodegradative bacteria, while oxygen concentration promoted the abundance of these bacteria. The results demonstrate the utility of multivariate statistical techniques as tools for estimating the magnitude and extent of pollution based on river water chemical and microbiological parameters. An evaluation of river chemical and microbiological data suggests that the ambient natural attenuation mechanisms only partly eliminate pollutants from river water, and that a sufficient reduction of more recalcitrant compounds could be achieved through the reduction of wastewater discharge from the oil-shale chemical industry into the rivers.

[Application of chemometrics in composition-activity relationship research of traditional Chinese medicine].

PubMed

Han, Sheng-Nan

2014-07-01

Chemometrics is a new branch of chemistry which is widely applied to various fields of analytical chemistry. Chemometrics can use theories and methods of mathematics, statistics, computer science and other related disciplines to optimize the chemical measurement process and maximize access to acquire chemical information and other information on material systems by analyzing chemical measurement data. In recent years, traditional Chinese medicine has attracted widespread attention. In the research of traditional Chinese medicine, it has been a key problem that how to interpret the relationship between various chemical components and its efficacy, which seriously restricts the modernization of Chinese medicine. As chemometrics brings the multivariate analysis methods into the chemical research, it has been applied as an effective research tool in the composition-activity relationship research of Chinese medicine. This article reviews the applications of chemometrics methods in the composition-activity relationship research in recent years. The applications of multivariate statistical analysis methods (such as regression analysis, correlation analysis, principal component analysis, etc. ) and artificial neural network (such as back propagation artificial neural network, radical basis function neural network, support vector machine, etc. ) are summarized, including the brief fundamental principles, the research contents and the advantages and disadvantages. Finally, the existing main problems and prospects of its future researches are proposed.

Calibrating Detailed Chemical Analysis of M dwarfs

NASA Astrophysics Data System (ADS)

Veyette, Mark; Muirhead, Philip Steven; Mann, Andrew; Brewer, John; Allard, France; Homeier, Derek

2018-01-01

The ability to perform detailed chemical analysis of Sun-like F-, G-, and K-type stars is a powerful tool with many applications including studying the chemical evolution of the Galaxy, assessing membership in stellar kinematic groups, and constraining planet formation theories. Unfortunately, complications in modeling cooler stellar atmospheres has hindered similar analysis of M-dwarf stars. Large surveys of FGK abundances play an important role in developing methods to measure the compositions of M dwarfs by providing benchmark FGK stars that have widely-separated M dwarf companions. These systems allow us to empirically calibrate metallicity-sensitive features in M dwarf spectra. However, current methods to measure metallicity in M dwarfs from moderate-resolution spectra are limited to measuring overall metallicity and largely rely on astrophysical abundance correlations in stellar populations. In this talk, I will discuss how large, homogeneous catalogs of precise FGK abundances are crucial to advancing chemical analysis of M dwarfs beyond overall metallicity to direct measurements of individual elemental abundances. I will present a new method to analyze high-resolution, NIR spectra of M dwarfs that employs an empirical calibration of synthetic M dwarf spectra to infer effective temperature, Fe abundance, and Ti abundance. This work is a step toward detailed chemical analysis of M dwarfs at a similar precision achieved for FGK stars.

Chemical information obtained from Auger depth profiles by means of advanced factor analysis (MLCFA)

NASA Astrophysics Data System (ADS)

De Volder, P.; Hoogewijs, R.; De Gryse, R.; Fiermans, L.; Vennik, J.

1993-01-01

The advanced multivariate statistical technique "maximum likelihood common factor analysis (MLCFA)" is shown to be superior to "principal component analysis (PCA)" for decomposing overlapping peaks into their individual component spectra of which neither the number of components nor the peak shape of the component spectra is known. An examination of the maximum resolving power of both techniques, MLCFA and PCA, by means of artificially created series of multicomponent spectra confirms this finding unambiguously. Substantial progress in the use of AES as a chemical-analysis technique is accomplished through the implementation of MLCFA. Chemical information from Auger depth profiles is extracted by investigating the variation of the line shape of the Auger signal as a function of the changing chemical state of the element. In particular, MLCFA combined with Auger depth profiling has been applied to problems related to steelcord-rubber tyre adhesion. MLCFA allows one to elucidate the precise nature of the interfacial layer of reaction products between natural rubber vulcanized on a thin brass layer. This study reveals many interesting chemical aspects of the oxi-sulfidation of brass undetectable with classical AES.

Spatially resolved chemical analysis of cicada wings using laser-ablation electrospray ionization (LAESI) imaging mass spectrometry (IMS).

PubMed

Román, Jessica K; Walsh, Callee M; Oh, Junho; Dana, Catherine E; Hong, Sungmin; Jo, Kyoo D; Alleyne, Marianne; Miljkovic, Nenad; Cropek, Donald M

2018-03-01

Laser-ablation electrospray ionization (LAESI) imaging mass spectrometry (IMS) is an emerging bioanalytical tool for direct imaging and analysis of biological tissues. Performing ionization in an ambient environment, this technique requires little sample preparation and no additional matrix, and can be performed on natural, uneven surfaces. When combined with optical microscopy, the investigation of biological samples by LAESI allows for spatially resolved compositional analysis. We demonstrate here the applicability of LAESI-IMS for the chemical analysis of thin, desiccated biological samples, specifically Neotibicen pruinosus cicada wings. Positive-ion LAESI-IMS accurate ion-map data was acquired from several wing cells and superimposed onto optical images allowing for compositional comparisons across areas of the wing. Various putative chemical identifications were made indicating the presence of hydrocarbons, lipids/esters, amines/amides, and sulfonated/phosphorylated compounds. With the spatial resolution capability, surprising chemical distribution patterns were observed across the cicada wing, which may assist in correlating trends in surface properties with chemical distribution. Observed ions were either (1) equally dispersed across the wing, (2) more concentrated closer to the body of the insect (proximal end), or (3) more concentrated toward the tip of the wing (distal end). These findings demonstrate LAESI-IMS as a tool for the acquisition of spatially resolved chemical information from fragile, dried insect wings. This LAESI-IMS technique has important implications for the study of functional biomaterials, where understanding the correlation between chemical composition, physical structure, and biological function is critical. Graphical abstract Positive-ion laser-ablation electrospray ionization mass spectrometry coupled with optical imaging provides a powerful tool for the spatially resolved chemical analysis of cicada wings.

Electron Spectroscopy for Chemical Analysis (ESCA) study of atmospheric particles

NASA Technical Reports Server (NTRS)

Dillard, J. G.; Seals, R. D.; Wightman, J. P.

1979-01-01

The results of analyses by ESCA (Electron Spectroscopy for Chemical Analysis) on several Nuclepore filters which were exposed during air pollution studies are presented along with correlative measurements by Neutron Activation Analysis and Scanning Electron Microscopy. Samples were exposed during air pollution studies at Norfolk, Virginia and the NASA Kennedy Space Center (KSC). It was demonstrated that with the ESCA technique it was possible to identify the chemical (bonding) state of elements contained in the atmospheric particulate matter collected on Nuclepore filters. Sulfur, nitrogen, mercury, chlorine, alkali, and alkaline earth metal species were identified in the Norfolk samples. ESCA binding energy data for aluminum indicated that three chemically different types of aluminum are present in the launch and background samples from NASA-KSC.

Chemical Analysis of Exhaled Human Breath Using High Resolution Mm-Wave Rotational Spectra

NASA Astrophysics Data System (ADS)

Guo, Tianle; Branco, Daniela; Thomas, Jessica; Medvedev, Ivan; Dolson, David; Nam, Hyun-Joo; O, Kenneth

2014-06-01

High resolution rotational spectroscopy enables chemical sensors that are both sensitive and highly specific, which is well suited for analysis of expired human breath. We have previously reported on detection of breath ethanol, methanol, acetone, and acetaldehyde using THz sensors. This paper will outline our present efforts in this area, with specific focus on our ongoing quest to correlate levels of blood glucose with concentrations of a few breath chemicals known to be affected by elevated blood sugar levels. Prospects, challenges and future plans will be outlined and discussed. Fosnight, A.M., B.L. Moran, and I.R. Medvedev, Chemical analysis of exhaled human breath using a terahertz spectroscopic approach. Applied Physics Letters, 2013. 103(13): p. 133703-5.

Natural Language Processor as a Universal Front End to Expert Systems.

DTIC Science & Technology

1983-12-01

EGaschnig 19791 4.1.7 ESCA SPECTRA INTERPRETER, ESCA (Electron Spectroscopy for Chemical Analysis) is ~ an expert system which directly processes...then used as input to the ESCA Interpreter program. The 0 program, like that of CRYSALIS, is intended to be used by and expert in the field of chemical ...expect to be there. For example, in the DENDRAL 0 chemical analysis system[Handbook of AI], chemical names such as benzene and methanol, must form part of

COMPARATIVE EVALUATION OF GC/MS (GAS CHROMATOGRAPHY/MASS SPECTROMETRY) DATA ANALYSIS PROCESSING

EPA Science Inventory

Mass spectra obtained by fused silica capillary gas chromatography/mass spectrometry/data system (GC/MS/DS) analysis of mixtures of organic chemicals adsorbed on Tenax GC cartridges was subjected to manual and automated interpretative techniques. Synthetic mixtures (85 chemicals ...

Airborne photography of chemical releases and analysis of twilight sky brightness data, phases 1 and 2

NASA Technical Reports Server (NTRS)

Bedinger, J. F.; Constantinides, E.

1976-01-01

The photography from aboard an aircraft of chemical releases is reported. The equipment installation on the aircraft is described, and photographs of the releases are included. An extensive analysis of twilight sky photographs is presented.

Methodology for national risk analysis and prioritization of toxic industrial chemicals.

PubMed

Taxell, Piia; Engström, Kerstin; Tuovila, Juha; Söderström, Martin; Kiljunen, Harri; Vanninen, Paula; Santonen, Tiina

2013-01-01

The identification of chemicals that pose the greatest threat to human health from incidental releases is a cornerstone in public health preparedness for chemical threats. The present study developed and applied a methodology for the risk analysis and prioritization of industrial chemicals to identify the most significant chemicals that pose a threat to public health in Finland. The prioritization criteria included acute and chronic health hazards, physicochemical and environmental hazards, national production and use quantities, the physicochemical properties of the substances, and the history of substance-related incidents. The presented methodology enabled a systematic review and prioritization of industrial chemicals for the purpose of national public health preparedness for chemical incidents.

Flight Deck Refuelling Hose Failure HMCS Preserver

DTIC Science & Technology

2000-01-01

hose and these were used as a basis for the investigation. Chemical analysis indicated that the inner tube and outer cover of the hose were as...Principal Results Chemical analysis indicated that the inner tube (poly(butadiene-acrylonitrile) rubber) and outer cover of the hose (poly( chloroprene... Analysis Py-GC/MS Instrumentation and Experimental Conditions Failed Titan Hose New Titan Hose German Hose Proof Tests Failed Titan Hose New

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.

Thermally emissive sensing materials for chemical spectroscopy analysis

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

Poole, Zsolt; Ohodnicki, Paul R.

A sensor using thermally emissive materials for chemical spectroscopy analysis includes an emissive material, wherein the emissive material includes the thermally emissive materials which emit electromagnetic radiation, wherein the electromagnetic radiation is modified due to chemical composition in an environment; and a detector adapted to detect the electromagnetic radiation, wherein the electromagnetic radiation is indicative of the chemical interaction changes and hence chemical composition and/or chemical composition changes of the environment. The emissive material can be utilized with an optical fiber sensor, with the optical fiber sensor operating without the emissive material probed with a light source external to themore » material.« less

A TIERED APPROACH TO PERFORMING UNCERTAINTY ANALYSIS IN CONDUCTING EXPOSURE ANALYSIS FOR CHEMICALS

EPA Science Inventory

The WHO/IPCS draft Guidance Document on Characterizing and Communicating Uncertainty in Exposure Assessment provides guidance on recommended strategies for conducting uncertainty analysis as part of human exposure analysis. Specifically, a tiered approach to uncertainty analysis ...

Functional Analysis of Metabolomics Data.

PubMed

Chagoyen, Mónica; López-Ibáñez, Javier; Pazos, Florencio

2016-01-01

Metabolomics aims at characterizing the repertory of small chemical compounds in a biological sample. As it becomes more massive and larger sets of compounds are detected, a functional analysis is required to convert these raw lists of compounds into biological knowledge. The most common way of performing such analysis is "annotation enrichment analysis," also used in transcriptomics and proteomics. This approach extracts the annotations overrepresented in the set of chemical compounds arisen in a given experiment. Here, we describe the protocols for performing such analysis as well as for visualizing a set of compounds in different representations of the metabolic networks, in both cases using free accessible web tools.

Improving the sensitivity and accuracy of gamma activation analysis for the rapid determination of gold in mineral ores.

PubMed

Tickner, James; Ganly, Brianna; Lovric, Bojan; O'Dwyer, Joel

2017-04-01

Mining companies rely on chemical analysis methods to determine concentrations of gold in mineral ore samples. As gold is often mined commercially at concentrations around 1 part-per-million, it is necessary for any analysis method to provide good sensitivity as well as high absolute accuracy. We describe work to improve both the sensitivity and accuracy of the gamma activation analysis (GAA) method for gold. We present analysis results for several suites of ore samples and discuss the design of a GAA facility designed to replace conventional chemical assay in industrial applications. Copyright © 2017. Published by Elsevier Ltd.

From Common Sense Concepts to Scientifically Conditioned Concepts of Chemical Bonding: An Historical and Textbook Approach Designed to Address Learning and Teaching Issues at the Secondary School Level

NASA Astrophysics Data System (ADS)

Croft, Michael; de Berg, Kevin

2014-09-01

This paper selects six key alternative conceptions identified in the literature on student understandings of chemical bonding and illustrates how a historical analysis and a textbook analysis can inform these conceptions and lead to recommendations for improving the teaching and learning of chemical bonding at the secondary school level. The historical analysis and the textbook analysis focus on the concepts of charge, octet, electron pair, ionic, covalent and metallic bonding. Finally, a table of recommendations is made for teacher and student in the light of four fundamental questions and the six alternative conceptions to enhance the quality of the curriculum resources available and the level of student engagement.

Device for high spatial resolution chemical analysis of a sample and method of high spatial resolution chemical analysis

DOEpatents

Van Berkel, Gary J.

2015-10-06

A system and method for analyzing a chemical composition of a specimen are described. The system can include at least one pin; a sampling device configured to contact a liquid with a specimen on the at least one pin to form a testing solution; and a stepper mechanism configured to move the at least one pin and the sampling device relative to one another. The system can also include an analytical instrument for determining a chemical composition of the specimen from the testing solution. In particular, the systems and methods described herein enable chemical analysis of specimens, such as tissue, to be evaluated in a manner that the spatial-resolution is limited by the size of the pins used to obtain tissue samples, not the size of the sampling device used to solubilize the samples coupled to the pins.

Capacitive chemical sensor

DOEpatents

Manginell, Ronald P; Moorman, Matthew W; Wheeler, David R

2014-05-27

A microfabricated capacitive chemical sensor can be used as an autonomous chemical sensor or as an analyte-sensitive chemical preconcentrator in a larger microanalytical system. The capacitive chemical sensor detects changes in sensing film dielectric properties, such as the dielectric constant, conductivity, or dimensionality. These changes result from the interaction of a target analyte with the sensing film. This capability provides a low-power, self-heating chemical sensor suitable for remote and unattended sensing applications. The capacitive chemical sensor also enables a smart, analyte-sensitive chemical preconcentrator. After sorption of the sample by the sensing film, the film can be rapidly heated to release the sample for further analysis. Therefore, the capacitive chemical sensor can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

A kinetic and equilibrium analysis of silicon carbide chemical vapor deposition on monofilaments

NASA Technical Reports Server (NTRS)

Gokoglu, S. A.; Kuczmarski, M. A.

1993-01-01

Chemical kinetics of atmospheric pressure silicon carbide (SiC) chemical vapor deposition (CVD) from dilute silane and propane source gases in hydrogen is numerically analyzed in a cylindrical upflow reactor designed for CVD on monofilaments. The chemical composition of the SiC deposit is assessed both from the calculated total fluxes of carbon and silicon and from chemical equilibrium considerations for the prevailing temperatures and species concentrations at and along the filament surface. The effects of gas and surface chemistry on the evolution of major gas phase species are considered in the analysis.

METHOD OF CHEMICAL ANALYSIS FOR OIL SHALE WASTES

EPA Science Inventory

Several methods of chemical analysis are described for oil shale wastewaters and retort gases. These methods are designed to support the field testing of various pollution control systems. As such, emphasis has been placed on methods which are rapid and sufficiently rugged to per...

Research Update: Spatially resolved mapping of electronic structure on atomic level by multivariate statistical analysis

DOE PAGES

Belianinov, Alex; Panchapakesan, G.; Lin, Wenzhi; ...

2014-12-02

Atomic level spatial variability of electronic structure in Fe-based superconductor FeTe0.55Se0.45 (Tc = 15 K) is explored using current-imaging tunneling-spectroscopy. Multivariate statistical analysis of the data differentiates regions of dissimilar electronic behavior that can be identified with the segregation of chalcogen atoms, as well as boundaries between terminations and near neighbor interactions. Subsequent clustering analysis allows identification of the spatial localization of these dissimilar regions. Similar statistical analysis of modeled calculated density of states of chemically inhomogeneous FeTe1 x Sex structures further confirms that the two types of chalcogens, i.e., Te and Se, can be identified by their electronic signaturemore » and differentiated by their local chemical environment. This approach allows detailed chemical discrimination of the scanning tunneling microscopy data including separation of atomic identities, proximity, and local configuration effects and can be universally applicable to chemically and electronically inhomogeneous surfaces.« less

Research Update: Spatially resolved mapping of electronic structure on atomic level by multivariate statistical analysis

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

Belianinov, Alex, E-mail: belianinova@ornl.gov; Ganesh, Panchapakesan; Lin, Wenzhi

2014-12-01

Atomic level spatial variability of electronic structure in Fe-based superconductor FeTe{sub 0.55}Se{sub 0.45} (T{sub c} = 15 K) is explored using current-imaging tunneling-spectroscopy. Multivariate statistical analysis of the data differentiates regions of dissimilar electronic behavior that can be identified with the segregation of chalcogen atoms, as well as boundaries between terminations and near neighbor interactions. Subsequent clustering analysis allows identification of the spatial localization of these dissimilar regions. Similar statistical analysis of modeled calculated density of states of chemically inhomogeneous FeTe{sub 1−x}Se{sub x} structures further confirms that the two types of chalcogens, i.e., Te and Se, can be identified bymore » their electronic signature and differentiated by their local chemical environment. This approach allows detailed chemical discrimination of the scanning tunneling microscopy data including separation of atomic identities, proximity, and local configuration effects and can be universally applicable to chemically and electronically inhomogeneous surfaces.« less

Chemical Differentiation of Osseous, Dental, and Non-skeletal Materials in Forensic Anthropology using Elemental Analysis.

PubMed

Zimmerman, Heather A; Meizel-Lambert, Cayli J; Schultz, John J; Sigman, Michael E

2015-03-01

Forensic anthropologists are generally able to identify skeletal materials (bone and tooth) using gross anatomical features; however, highly fragmented or taphonomically altered materials may be problematic to identify. Several chemical analysis techniques have been shown to be reliable laboratory methods that can be used to determine if questionable fragments are osseous, dental, or non-skeletal in nature. The purpose of this review is to provide a detailed background of chemical analysis techniques focusing on elemental compositions that have been assessed for use in differentiating osseous, dental, and non-skeletal materials. More recently, chemical analysis studies have also focused on using the elemental composition of osseous/dental materials to evaluate species and provide individual discrimination, but have generally been successful only in small, closed groups, limiting their use forensically. Despite significant advances incorporating a variety of instruments, including handheld devices, further research is necessary to address issues in standardization, error rates, and sample size/diversity. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

Biological and chemical removal of Cr(VI) from waste water: cost and benefit analysis.

PubMed

Demir, Aynur; Arisoy, Münevver

2007-08-17

The objective of the present study is cost and benefit analysis of biological and chemical removal of hexavalent chromium [Cr(VI)] ions. Cost and benefit analysis were done with refer to two separate studies on removal of Cr(VI), one of heavy metals with a crucial role concerning increase in environmental pollution and disturbance of ecological balance, through biological adsorption and chemical ion-exchange. Methods of biological and chemical removal were compared with regard to their cost and percentage in chrome removal. According to the result of the comparison, cost per unit in chemical removal was calculated 0.24 euros and the ratio of chrome removal was 99.68%, whereas those of biological removal were 0.14 and 59.3% euros. Therefore, it was seen that cost per unit in chemical removal and chrome removal ratio were higher than those of biological removal method. In the current study where chrome removal is seen as immeasurable benefit in terms of human health and the environment, percentages of chrome removal were taken as measurable benefit and cost per unit of the chemicals as measurable cost.

From Common Sense Concepts to Scientifically Conditioned Concepts of Chemical Bonding: An Historical and Textbook Approach Designed to Address Learning and Teaching Issues at the Secondary School Level

ERIC Educational Resources Information Center

Croft, Michael; de Berg, Kevin

2014-01-01

This paper selects six key alternative conceptions identified in the literature on student understandings of chemical bonding and illustrates how a historical analysis and a textbook analysis can inform these conceptions and lead to recommendations for improving the teaching and learning of chemical bonding at the secondary school level. The…

Naval Research Laboratory Industrial Chemical Analysis and Respiratory Filter Standards Development

DTIC Science & Technology

2017-09-29

Filter Standards Development September 29, 2017 Approved for public release; distribution is unlimited. Thomas E. suTTo Materials and Systems Branch...LIMITATION OF ABSTRACT Naval Research Laboratory Industrial Chemical Analysis and Respiratory Filter Standards Development Thomas E. Sutto Naval Research...approach, developed by NRL, is tested by examining the filter behavior against a number of chemicals to determine if the NRL approach resulted in the

Microfluidic electrochemical device and process for chemical imaging and electrochemical analysis at the electrode-liquid interface in-situ

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

Yu, Xiao-Ying; Liu, Bingwen; Yang, Li

2016-03-01

A microfluidic electrochemical device and process are detailed that provide chemical imaging and electrochemical analysis under vacuum at the surface of the electrode-sample or electrode-liquid interface in-situ. The electrochemical device allows investigation of various surface layers including diffuse layers at selected depths populated with, e.g., adsorbed molecules in which chemical transformation in electrolyte solutions occurs.

Microscale Procedure for Inorganic Qualitative Analysis with Emphasis on Writing Equations: Chemical Fingerprinting Applied to the "n"-bottle Problem of Matching Samples with Their Formulas

ERIC Educational Resources Information Center

Sattsangi, Prem D.

2014-01-01

A laboratory method for teaching inorganic qualitative analysis and chemical equations is described. The experiment has been designed to focus attention on cations and anions that react to form products. This leads to a logical approach to understand and write chemical equations. The procedure uses 3 mL plastic micropipettes to store and deliver…

Rapid Characterization of Components in Bolbostemma paniculatum by UPLC/LTQ-Orbitrap MSn Analysis and Multivariate Statistical Analysis for Herb Discrimination.

PubMed

Zeng, Yanling; Lu, Yang; Chen, Zhao; Tan, Jiawei; Bai, Jie; Li, Pengyue; Wang, Zhixin; Du, Shouying

2018-05-11

Bolbostemma paniculatum is a traditional Chinese medicine (TCM) showed various therapeutic effects. Owing to its complex chemical composition, few investigations have acquired a comprehensive cognition for the chemical profiles of this herb and explicated the differences between samples collected from different places. In this study, a strategy based on UPLC tandem LTQ-Orbitrap MS n was established for characterizing chemical components of B. paniculatum . Through a systematic identification strategy, a total of 60 components in B. paniculatum were rapidly separated in 30 min and identified. Then based on peak intensities of all the characterized components, principle component analysis (PCA) and hierarchical cluster analysis (HCA) were employed to classify 18 batches of B. paniculatum into four groups, which were highly consistent with the four climate types of their original places. And five compounds were finally screened out as chemical markers to discriminate the internal quality of B. paniculatum . As the first study to systematically characterize the chemical components of B. paniculatum by UPLC-MS n , the above results could offer essential data for its pharmacological research. And the current strategy could provide useful reference for future investigations on discovery of important chemical constituents in TCM, as well as establishment of quality control and evaluation method.

Methods for spectral image analysis by exploiting spatial simplicity

DOEpatents

Keenan, Michael R.

2010-05-25

Several full-spectrum imaging techniques have been introduced in recent years that promise to provide rapid and comprehensive chemical characterization of complex samples. One of the remaining obstacles to adopting these techniques for routine use is the difficulty of reducing the vast quantities of raw spectral data to meaningful chemical information. Multivariate factor analysis techniques, such as Principal Component Analysis and Alternating Least Squares-based Multivariate Curve Resolution, have proven effective for extracting the essential chemical information from high dimensional spectral image data sets into a limited number of components that describe the spectral characteristics and spatial distributions of the chemical species comprising the sample. There are many cases, however, in which those constraints are not effective and where alternative approaches may provide new analytical insights. For many cases of practical importance, imaged samples are "simple" in the sense that they consist of relatively discrete chemical phases. That is, at any given location, only one or a few of the chemical species comprising the entire sample have non-zero concentrations. The methods of spectral image analysis of the present invention exploit this simplicity in the spatial domain to make the resulting factor models more realistic. Therefore, more physically accurate and interpretable spectral and abundance components can be extracted from spectral images that have spatially simple structure.

Methods for spectral image analysis by exploiting spatial simplicity

DOEpatents

Keenan, Michael R.

2010-11-23

Several full-spectrum imaging techniques have been introduced in recent years that promise to provide rapid and comprehensive chemical characterization of complex samples. One of the remaining obstacles to adopting these techniques for routine use is the difficulty of reducing the vast quantities of raw spectral data to meaningful chemical information. Multivariate factor analysis techniques, such as Principal Component Analysis and Alternating Least Squares-based Multivariate Curve Resolution, have proven effective for extracting the essential chemical information from high dimensional spectral image data sets into a limited number of components that describe the spectral characteristics and spatial distributions of the chemical species comprising the sample. There are many cases, however, in which those constraints are not effective and where alternative approaches may provide new analytical insights. For many cases of practical importance, imaged samples are "simple" in the sense that they consist of relatively discrete chemical phases. That is, at any given location, only one or a few of the chemical species comprising the entire sample have non-zero concentrations. The methods of spectral image analysis of the present invention exploit this simplicity in the spatial domain to make the resulting factor models more realistic. Therefore, more physically accurate and interpretable spectral and abundance components can be extracted from spectral images that have spatially simple structure.

Chemical imaging of molecular changes in a hydrated single cell by dynamic secondary ion mass spectrometry and super-resolution microscopy

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

Hua, Xin; Szymanski, Craig; Wang, Zhaoying

2016-01-01

Chemical imaging of single cells is important in capturing biological dynamics. Single cell correlative imaging is realized between structured illumination microscopy (SIM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) using System for Analysis at the Liquid Vacuum Interface (SALVI), a multimodal microreactor. SIM characterized cells and guided subsequent ToF-SIMS analysis. Dynamic ToF-SIMS provided time- and space-resolved cell molecular mapping. Lipid fragments were identified in the hydrated cell membrane. Principal component analysis was used to elucidate chemical component differences among mouse lung cells that uptake zinc oxide nanoparticles. Our results provided submicron chemical spatial mapping for investigations of cell dynamics atmore » the molecular level.« less

Analysis of air-, moisture- and solvent-sensitive chemical compounds by mass spectrometry using an inert atmospheric pressure solids analysis probe.

PubMed

Mosely, Jackie A; Stokes, Peter; Parker, David; Dyer, Philip W; Messinis, Antonis M

2018-02-01

A novel method has been developed that enables chemical compounds to be transferred from an inert atmosphere glove box and into the atmospheric pressure ion source of a mass spectrometer whilst retaining a controlled chemical environment. This innovative method is simple and cheap to implement on some commercially available mass spectrometers. We have termed this approach inert atmospheric pressure solids analysis probe ( iASAP) and demonstrate the benefit of this methodology for two air-/moisture-sensitive chemical compounds whose characterisation by mass spectrometry is now possible and easily achieved. The simplicity of the design means that moving between iASAP and standard ASAP is straightforward and quick, providing a highly flexible platform with rapid sample turnaround.

Advancements in mass spectrometry for biological samples: Protein chemical cross-linking and metabolite analysis of plant tissues

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

Klein, Adam

2015-01-01

This thesis presents work on advancements and applications of methodology for the analysis of biological samples using mass spectrometry. Included in this work are improvements to chemical cross-linking mass spectrometry (CXMS) for the study of protein structures and mass spectrometry imaging and quantitative analysis to study plant metabolites. Applications include using matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) to further explore metabolic heterogeneity in plant tissues and chemical interactions at the interface between plants and pests. Additional work was focused on developing liquid chromatography-mass spectrometry (LC-MS) methods to investigate metabolites associated with plant-pest interactions.

Quantification of the effects of secondary matrix on the analysis of sandstone composition, and a petrographic-chemical technique for retrieving original framework grain modes of altered sandstones.

PubMed

Cox, R; Lowe, D R

1996-05-01

Most studies of sandstone provenance involve modal analysis of framework grains using techniques that exclude the fine-grained breakdown products of labile mineral grains and rock fragments, usually termed secondary matrix or pseudomatrix. However, the data presented here demonstrate that, when the proportion of pseudomatrix in a sandstone exceeds 10%, standard petrographic analysis can lead to incorrect provenance interpretation. Petrographic schemes for provenance analysis such as QFL and QFR should not therefore be applied to sandstones containing more than 10% secondary matrix. Pseudomatrix is commonly abundant in sandstones, and this is therefore a problem for provenance analysis. The difficulty can be alleviated by the use of whole-rock chemistry in addition to petrographic analysis. Combination of chemical and point-count data permits the construction of normative compositions that approximate original framework grain compositions. Provenance analysis is also complicated in many cases by fundamental compositional alteration during weathering and transport. Many sandstones, particularly shallow marine deposits, have undergone vigorous reworking, which may destroy unstable mineral grains and rock fragments. In such cases it may not be possible to retrieve provenance information by either petrographic or chemical means. Because of this, pseudomatrix-rich sandstones should be routinely included in chemical-petrological provenance analysis. Because of the many factors, both pre- and post-depositional, that operate to increase the compositional maturity of sandstones, petrologic studies must include a complete inventory of matrix proportions, grain size and sorting parameters, and an assessment of depositional setting.

Proposed minimum reporting standards for chemical analysis Chemical Analysis Working Group (CAWG) Metabolomics Standards Initiative (MSI)

PubMed Central

Amberg, Alexander; Barrett, Dave; Beale, Michael H.; Beger, Richard; Daykin, Clare A.; Fan, Teresa W.-M.; Fiehn, Oliver; Goodacre, Royston; Griffin, Julian L.; Hankemeier, Thomas; Hardy, Nigel; Harnly, James; Higashi, Richard; Kopka, Joachim; Lane, Andrew N.; Lindon, John C.; Marriott, Philip; Nicholls, Andrew W.; Reily, Michael D.; Thaden, John J.; Viant, Mark R.

2013-01-01

There is a general consensus that supports the need for standardized reporting of metadata or information describing large-scale metabolomics and other functional genomics data sets. Reporting of standard metadata provides a biological and empirical context for the data, facilitates experimental replication, and enables the re-interrogation and comparison of data by others. Accordingly, the Metabolomics Standards Initiative is building a general consensus concerning the minimum reporting standards for metabolomics experiments of which the Chemical Analysis Working Group (CAWG) is a member of this community effort. This article proposes the minimum reporting standards related to the chemical analysis aspects of metabolomics experiments including: sample preparation, experimental analysis, quality control, metabolite identification, and data pre-processing. These minimum standards currently focus mostly upon mass spectrometry and nuclear magnetic resonance spectroscopy due to the popularity of these techniques in metabolomics. However, additional input concerning other techniques is welcomed and can be provided via the CAWG on-line discussion forum at http://msi-workgroups.sourceforge.net/ or http://Msi-workgroups-feedback@lists.sourceforge.net. Further, community input related to this document can also be provided via this electronic forum. PMID:24039616

Meta-analysis of toxicity and teratogenicity of 133 chemicals from zebrafish developmental toxicity studies

EPA Science Inventory

Zebrafish developmental toxicity testing is an emerging field, which faces considerable challenges regarding data meta-analysis and the establishment of standardized test protocols. Here, we present an initial correlation study on toxicity of 133 chemicals based on data in the li...

40 CFR 125.66 - Toxics control program.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... (1) An applicant that has known or suspected industrial sources of toxic pollutants shall have an... any applicant which has no known or suspected industrial sources of toxic pollutants or pesticides and.... (a) Chemical analysis. (1) The applicant shall submit at the time of application a chemical analysis...

Effect-directed analysis supporting monitoring of aquatic environments - An in-depth overview

EPA Science Inventory

Aquatic environments are often contaminated with complex mixtures of chemicals that may pose a risk to ecosystems and human health. This contamination cannot be addressed with target analysis alone but tools are required to reduce this complexity and identify those chemicals that...

Chemical analysis of plants that poison livestock: Successes, challenges, and opportunities

USDA-ARS?s Scientific Manuscript database

Poisonous plants have a devastating impact on the livestock industry, as well as human health. In order to fully understand the effects of poisonous plants, multiple scientific disciplines are required. Chemical analysis of plant secondary compounds is key to identifying the responsible toxins, char...

Multivariate analysis of chromatographic retention data as a supplementary means for grouping structurally related compounds.

PubMed

Fasoula, S; Zisi, Ch; Sampsonidis, I; Virgiliou, Ch; Theodoridis, G; Gika, H; Nikitas, P; Pappa-Louisi, A

2015-03-27

In the present study a series of 45 metabolite standards belonging to four chemically similar metabolite classes (sugars, amino acids, nucleosides and nucleobases, and amines) was subjected to LC analysis on three HILIC columns under 21 different gradient conditions with the aim to explore whether the retention properties of these analytes are determined from the chemical group they belong. Two multivariate techniques, principal component analysis (PCA) and discriminant analysis (DA), were used for statistical evaluation of the chromatographic data and extraction similarities between chemically related compounds. The total variance explained by the first two principal components of PCA was found to be about 98%, whereas both statistical analyses indicated that all analytes are successfully grouped in four clusters of chemical structure based on the retention obtained in four or at least three chromatographic runs, which, however should be performed on two different HILIC columns. Moreover, leave-one-out cross-validation of the above retention data set showed that the chemical group in which an analyte belongs can be 95.6% correctly predicted when the analyte is subjected to LC analysis under the same four or three experimental conditions as the all set of analytes was run beforehand. That, in turn, may assist with disambiguation of analyte identification in complex biological extracts. Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis and comparison of biomass pyrolysis/gasification condensates: Final report

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

Elliott, D.C.

1986-06-01

This report provides results of chemical and physical analysis of condensates from eleven biomass gasification and pyrolysis systems. The samples were representative of the various reactor configurations being researched within the Department of Energy, Biomass Thermochemical Conversion program. The condensates included tar phases and aqueous phases. The analyses included gross compositional analysis (elemental analysis, ash, moisture), physical characterization (pour point, viscosity, density, heat of combustion, distillation), specific chemical analysis (gas chromatography/mass spectrometry, infrared spectrophotometry, proton and carbon-13 nuclear magnetic resonance spectrometry) and biological activity (Ames assay and mouse skin tumorigenicity tests). These results are the first step of a longermore » term program to determine the properties, handling requirements, and utility of the condensates recovered from biomass gasification and pyrolysis. The analytical data demonstrates the wide range of chemical composition of the organics recovered in the condensates and suggests a direct relationship between operating temperature and chemical composition of the condensates. A continuous pathway of thermal degradation of the tar components as a function of temperature is proposed. Variations in the chemical composition of the organic components in the tars are reflected in the physical properties of tars and phase stability in relation to water in the condensate. The biological activity appears to be limited to the tars produced at high temperatures. 56 refs., 25 figs., 21 tabs.« less

Terpenoid Variations within and among Half-Sibling Avocado Trees, Persea americana Mill. (Lauraceae)

PubMed Central

Niogret, Jerome; Epsky, Nancy D.; Schnell, Raymond J.; Boza, Edward J.; Kendra, Paul E.; Heath, Robert R.

2013-01-01

Chemical analyses were conducted to determine the qualitative and quantitative differences in monoterpenes and sesquiterpenes in plant material from avocado trees, Persea americana Mill. (Lauraceae). The initial study analyzed plant material sampled from the trunk to the leaves through different branch diameters to quantify proximo-distal spatial differences within a tree. All trees were seedlings initiated from a single maternal tree. Two-way analysis of variance was conducted on 34 chemicals that comprised at least 3% of the total chemical content of at least one tree and/or location within a tree. There were significant interactions between genotype and location sampled for most chemicals. Parentage analysis using microsatellite molecular markers (SSR's) determined that the four trees had three fathers and that they represented two full-siblings and two half-sibling trees. Descriptive discriminant analysis found that both genotype and location within a tree could be separated based on chemical content, and that the chemical content from full-siblings tended to be more similar than chemical content from half-siblings. To further explore the relationship between genetic background and chemical content, samples were analyzed from leaf material from 20 trees that included two sets of full-sibling seedling trees, the maternal tree and the surviving paternal tree. Descriptive discriminant analysis found good separation between the two full-sibling groups, and that the separation was associated with chemistry of the parental trees. Six groups of chemicals were identified that explained the variation among the trees. We discuss the results in relation to the discrimination process used by wood-boring insects for site-selection on host trees, for tree selection among potential host trees, and the potential use of terpenoid chemical content in chemotaxonomy of avocado trees. PMID:24039994

Terpenoid variations within and among half-sibling avocado trees, Persea americana Mill. (Lauraceae).

PubMed

Niogret, Jerome; Epsky, Nancy D; Schnell, Raymond J; Boza, Edward J; Kendra, Paul E; Heath, Robert R

2013-01-01

Chemical analyses were conducted to determine the qualitative and quantitative differences in monoterpenes and sesquiterpenes in plant material from avocado trees, Persea americana Mill. (Lauraceae). The initial study analyzed plant material sampled from the trunk to the leaves through different branch diameters to quantify proximo-distal spatial differences within a tree. All trees were seedlings initiated from a single maternal tree. Two-way analysis of variance was conducted on 34 chemicals that comprised at least 3% of the total chemical content of at least one tree and/or location within a tree. There were significant interactions between genotype and location sampled for most chemicals. Parentage analysis using microsatellite molecular markers (SSR's) determined that the four trees had three fathers and that they represented two full-siblings and two half-sibling trees. Descriptive discriminant analysis found that both genotype and location within a tree could be separated based on chemical content, and that the chemical content from full-siblings tended to be more similar than chemical content from half-siblings. To further explore the relationship between genetic background and chemical content, samples were analyzed from leaf material from 20 trees that included two sets of full-sibling seedling trees, the maternal tree and the surviving paternal tree. Descriptive discriminant analysis found good separation between the two full-sibling groups, and that the separation was associated with chemistry of the parental trees. Six groups of chemicals were identified that explained the variation among the trees. We discuss the results in relation to the discrimination process used by wood-boring insects for site-selection on host trees, for tree selection among potential host trees, and the potential use of terpenoid chemical content in chemotaxonomy of avocado trees.

Chemical Fingerprint and Quantitative Analysis for the Quality Evaluation of Docynia dcne Leaves by High-Performance Liquid Chromatography Coupled with Chemometrics Analysis.

PubMed

Zhang, Xiaoyu; Mei, Xueran; Wang, Zhanguo; Wu, Jing; Liu, Gang; Hu, Huiling; Li, Qijuan

2018-05-24

Docynia dcne leaf from the genus of Docynia Dcne (including three species of Docynia delavayi, Docynia indica and Docynia longiunguis.) is an important raw material of local ethnic minority tea, ethnomedicines and food supplements in southwestern areas of China. However, D. dcne leaves from these three species are usually used confusingly, which could influence the therapeutic effect of it. A rapid and effective method for the chemical fingerprint and quantitative analysis to evaluate the quality of D. dcne leaves was established. The chemometric methods, including similarity analysis, hierarchical cluster analysis and partial least-squares discrimination analysis, were applied to distinguish 30 batches of D. dcne leaf samples from these three species. The above results could validate each other and successfully group these samples into three categories which were closely related to the species of D. dcne leaves. Moreover, isoquercitrin and phlorizin were screened as the chemical markers to evaluate the quality of D. dcne leaves from different species. And the contents of isoquercitrin and phlorizin varied remarkably in these samples, with ranges of 6.41-38.84 and 95.73-217.76 mg/g, respectively. All the results indicated that an integration method of chemical fingerprint couple with chemometrics analysis and quantitative assessment was a powerful and beneficial tool for quality control of D. dcne leaves, and could be applied also for differentiation and quality control of other herbal preparations.

Fingerprint analysis of Hibiscus mutabilis L. leaves based on ultra performance liquid chromatography with photodiode array detector combined with similarity analysis and hierarchical clustering analysis methods

PubMed Central

Liang, Xianrui; Ma, Meiling; Su, Weike

2013-01-01

Background: A method for chemical fingerprint analysis of Hibiscus mutabilis L. leaves was developed based on ultra performance liquid chromatography with photodiode array detector (UPLC-PAD) combined with similarity analysis (SA) and hierarchical clustering analysis (HCA). Materials and Methods: 10 batches of Hibiscus mutabilis L. leaves samples were collected from different regions of China. UPLC-PAD was employed to collect chemical fingerprints of Hibiscus mutabilis L. leaves. Results: The relative standard deviations (RSDs) of the relative retention times (RRT) and relative peak areas (RPA) of 10 characteristic peaks (one of them was identified as rutin) in precision, repeatability and stability test were less than 3%, and the method of fingerprint analysis was validated to be suitable for the Hibiscus mutabilis L. leaves. Conclusions: The chromatographic fingerprints showed abundant diversity of chemical constituents qualitatively in the 10 batches of Hibiscus mutabilis L. leaves samples from different locations by similarity analysis on basis of calculating the correlation coefficients between each two fingerprints. Moreover, the HCA method clustered the samples into four classes, and the HCA dendrogram showed the close or distant relations among the 10 samples, which was consistent to the SA result to some extent. PMID:23930008

NIR and Py-mbms coupled with multivariate data analysis as a high-throughput biomass characterization technique: a review

PubMed Central

Xiao, Li; Wei, Hui; Himmel, Michael E.; Jameel, Hasan; Kelley, Stephen S.

2014-01-01

Optimizing the use of lignocellulosic biomass as the feedstock for renewable energy production is currently being developed globally. Biomass is a complex mixture of cellulose, hemicelluloses, lignins, extractives, and proteins; as well as inorganic salts. Cell wall compositional analysis for biomass characterization is laborious and time consuming. In order to characterize biomass fast and efficiently, several high through-put technologies have been successfully developed. Among them, near infrared spectroscopy (NIR) and pyrolysis-molecular beam mass spectrometry (Py-mbms) are complementary tools and capable of evaluating a large number of raw or modified biomass in a short period of time. NIR shows vibrations associated with specific chemical structures whereas Py-mbms depicts the full range of fragments from the decomposition of biomass. Both NIR vibrations and Py-mbms peaks are assigned to possible chemical functional groups and molecular structures. They provide complementary information of chemical insight of biomaterials. However, it is challenging to interpret the informative results because of the large amount of overlapping bands or decomposition fragments contained in the spectra. In order to improve the efficiency of data analysis, multivariate analysis tools have been adapted to define the significant correlations among data variables, so that the large number of bands/peaks could be replaced by a small number of reconstructed variables representing original variation. Reconstructed data variables are used for sample comparison (principal component analysis) and for building regression models (partial least square regression) between biomass chemical structures and properties of interests. In this review, the important biomass chemical structures measured by NIR and Py-mbms are summarized. The advantages and disadvantages of conventional data analysis methods and multivariate data analysis methods are introduced, compared and evaluated. This review aims to serve as a guide for choosing the most effective data analysis methods for NIR and Py-mbms characterization of biomass. PMID:25147552

Determinants of job stress in chemical process industry: A factor analysis approach.

PubMed

Menon, Balagopal G; Praveensal, C J; Madhu, G

2015-01-01

Job stress is one of the active research domains in industrial safety research. The job stress can result in accidents and health related issues in workers in chemical process industries. Hence it is important to measure the level of job stress in workers so as to mitigate the same to avoid the worker's safety related problems in the industries. The objective of this study is to determine the job stress factors in the chemical process industry in Kerala state, India. This study also aims to propose a comprehensive model and an instrument framework for measuring job stress levels in the chemical process industries in Kerala, India. The data is collected through a questionnaire survey conducted in chemical process industries in Kerala. The collected data out of 1197 surveys is subjected to principal component and confirmatory factor analysis to develop the job stress factor structure. The factor analysis revealed 8 factors that influence the job stress in process industries. It is also found that the job stress in employees is most influenced by role ambiguity and the least by work environment. The study has developed an instrument framework towards measuring job stress utilizing exploratory factor analysis and structural equation modeling.

Method for detection of selected chemicals in an open environment

NASA Technical Reports Server (NTRS)

Duong, Tuan (Inventor); Ryan, Margaret (Inventor)

2009-01-01

The present invention relates to a space-invariant independent component analysis and electronic nose for detection of selective chemicals in an unknown environment, and more specifically, an approach to analysis of sensor responses to mixtures of unknown chemicals by an electronic nose in an open and changing environment. It is intended to fill the gap between an alarm, which has little or no ability to distinguish among chemical compounds causing a response, and an analytical instrument, which can distinguish all compounds present but with no real-time or continuous event monitoring ability.

Physical vs. photolithographic patterning of plasma polymers: an investigation by ToF-SSIMS and multivariate analysis

PubMed Central

Mishra, Gautam; Easton, Christopher D.; McArthur, Sally L.

2009-01-01

Physical and photolithographic techniques are commonly used to create chemical patterns for a range of technologies including cell culture studies, bioarrays and other biomedical applications. In this paper, we describe the fabrication of chemical micropatterns from commonly used plasma polymers. Atomic force microcopy (AFM) imaging, Time-of-Flight Static Secondary Ion Mass Spectrometry (ToF-SSIMS) imaging and multivariate analysis have been employed to visualize the chemical boundaries created by these patterning techniques and assess the spatial and chemical resolution of the patterns. ToF-SSIMS analysis demonstrated that well defined chemical and spatial boundaries were obtained from photolithographic patterning, while the resolution of physical patterning via a transmission electron microscopy (TEM) grid varied depending on the properties of the plasma system including the substrate material. In general, physical masking allowed diffusion of the plasma species below the mask and bleeding of the surface chemistries. Multivariate analysis techniques including Principal Component Analysis (PCA) and Region of Interest (ROI) assessment were used to investigate the ToF-SSIMS images of a range of different plasma polymer patterns. In the most challenging case, where two strongly reacting polymers, allylamine and acrylic acid were deposited, PCA confirmed the fabrication of micropatterns with defined spatial resolution. ROI analysis allowed for the identification of an interface between the two plasma polymers for patterns fabricated using the photolithographic technique which has been previously overlooked. This study clearly demonstrated the versatility of photolithographic patterning for the production of multichemistry plasma polymer arrays and highlighted the need for complimentary characterization and analytical techniques during the fabrication plasma polymer micropatterns. PMID:19950941

USE OF BIOASSAY-DIRECTED CHEMICAL ANALYSIS FOR IDENTIFYING MUTAGENIC COMPOUNDS IN URBAN AIR AND COMBUSTION EMISSIONS

EPA Science Inventory

Bioassay-directed chemical analysis fractionation has been used for 30 years to identify mutagenic classes of compounds in complex mixtures. Most studies have used the Salmonella (Ames) mutagenicity assay, and we have recently applied this methodology to two standard reference sa...

Role of Service Learning in Water Quality Studies

ERIC Educational Resources Information Center

Richards, Wilfred Sugumar

2009-01-01

Background: Chemistry students often complain that they are unmotivated because they see no applications of chemical principles in "real life." It was thus decided to put into use the knowledge gained during the course on water quality and analysis. Learning the principles of quantitative chemical analysis requires innovative, hands-on…

Derivation of Tissue-specific Functional Gene Sets to Aid Transcriptomic Analysis of Chemical Impacts on the Teleost Reproductive Axis.

EPA Science Inventory

Oligonucleotide microarrays are a powerful tool for unsupervised analysis of chemical impacts on biological systems. However, the lack of well annotated biological pathways for many aquatic organisms, including fish, and the poor power of microarray-based analyses to detect diffe...

Fertilizer/Chemical Sales and Service Worker. Ohio's Competency Analysis Profile.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

This Ohio Competency Analysis Profile (OCAP), derived from a modified Developing a Curriculum (DACUM) process, is a current comprehensive and verified employer competency program list for fertilizer/chemical sales and service workers. Each unit (with or without subunits) contains competencies and competency builders that identify the occupational,…

A PROBABALISTIC ANALYSIS TO DETERMINE ECOLOGICAL RISK DRIVERS, 10TH VOLUME ASTM STP 1403

EPA Science Inventory

A probabilistic analysis of exposure and effect data was used to identify chemicals most likely responsible for ecological risk. The mean and standard deviation of the natural log-transformed chemical data were used to estimate the probability of exposure for an area of concern a...

Quality Assessment of Urinary Stone Analysis: Results of a Multicenter Study of Laboratories in Europe

PubMed Central

Siener, Roswitha; Buchholz, Noor; Daudon, Michel; Hess, Bernhard; Knoll, Thomas; Osther, Palle J.; Reis-Santos, José; Sarica, Kemal; Traxer, Olivier; Trinchieri, Alberto

2016-01-01

After stone removal, accurate analysis of urinary stone composition is the most crucial laboratory diagnostic procedure for the treatment and recurrence prevention in the stone-forming patient. The most common techniques for routine analysis of stones are infrared spectroscopy, X-ray diffraction and chemical analysis. The aim of the present study was to assess the quality of urinary stone analysis of laboratories in Europe. Nine laboratories from eight European countries participated in six quality control surveys for urinary calculi analyses of the Reference Institute for Bioanalytics, Bonn, Germany, between 2010 and 2014. Each participant received the same blinded test samples for stone analysis. A total of 24 samples, comprising pure substances and mixtures of two or three components, were analysed. The evaluation of the quality of the laboratory in the present study was based on the attainment of 75% of the maximum total points, i.e. 99 points. The methods of stone analysis used were infrared spectroscopy (n = 7), chemical analysis (n = 1) and X-ray diffraction (n = 1). In the present study only 56% of the laboratories, four using infrared spectroscopy and one using X-ray diffraction, fulfilled the quality requirements. According to the current standard, chemical analysis is considered to be insufficient for stone analysis, whereas infrared spectroscopy or X-ray diffraction is mandatory. However, the poor results of infrared spectroscopy highlight the importance of equipment, reference spectra and qualification of the staff for an accurate analysis of stone composition. Regular quality control is essential in carrying out routine stone analysis. PMID:27248840

Quality Assessment of Urinary Stone Analysis: Results of a Multicenter Study of Laboratories in Europe.

PubMed

Siener, Roswitha; Buchholz, Noor; Daudon, Michel; Hess, Bernhard; Knoll, Thomas; Osther, Palle J; Reis-Santos, José; Sarica, Kemal; Traxer, Olivier; Trinchieri, Alberto

2016-01-01

After stone removal, accurate analysis of urinary stone composition is the most crucial laboratory diagnostic procedure for the treatment and recurrence prevention in the stone-forming patient. The most common techniques for routine analysis of stones are infrared spectroscopy, X-ray diffraction and chemical analysis. The aim of the present study was to assess the quality of urinary stone analysis of laboratories in Europe. Nine laboratories from eight European countries participated in six quality control surveys for urinary calculi analyses of the Reference Institute for Bioanalytics, Bonn, Germany, between 2010 and 2014. Each participant received the same blinded test samples for stone analysis. A total of 24 samples, comprising pure substances and mixtures of two or three components, were analysed. The evaluation of the quality of the laboratory in the present study was based on the attainment of 75% of the maximum total points, i.e. 99 points. The methods of stone analysis used were infrared spectroscopy (n = 7), chemical analysis (n = 1) and X-ray diffraction (n = 1). In the present study only 56% of the laboratories, four using infrared spectroscopy and one using X-ray diffraction, fulfilled the quality requirements. According to the current standard, chemical analysis is considered to be insufficient for stone analysis, whereas infrared spectroscopy or X-ray diffraction is mandatory. However, the poor results of infrared spectroscopy highlight the importance of equipment, reference spectra and qualification of the staff for an accurate analysis of stone composition. Regular quality control is essential in carrying out routine stone analysis.

Chemical probes for analysis of carbonylated proteins: a review

PubMed Central

Yan, Liang-Jun; Forster, Michael J.

2010-01-01

Protein carbonylation is a major form of protein oxidation and is widely used as an indicator of oxidative stress. Carbonyl groups do not have distinguishing UV or visible, spectrophotometric absorbance/fluorescence characteristics and thus their detection and quantification can only be achieved using specific chemical probes. In this paper, we review the advantages and disadvantages of several chemical probes that have been and are still being used for protein carbonyl analysis. These probes include 2, 4-dinitrophenylhydazine (DNPH), tritiated sodium borohydride ([3H]NaBH4), biotin-containing probes, and fluorescence probes. As our discussions lean toward gel-based approaches, utilizations of these probes in 2D gel-based proteomic analysis of carbonylated proteins are illustrated where applicable. Analysis of carbonylated proteins by ELISA, immunofluorescent imaging, near infrared fluorescence detection, and gel-free proteomic approaches are also discussed where appropriate. Additionally, potential applications of blue native gel electrophoresis as a tool for first dimensional separation in 2D gel-based analysis of carbonylated proteins are discussed as well. PMID:20732835

Systems Analysis Directorate Activities Summary - September 1977. Volume 1

DTIC Science & Technology

1977-10-01

Identify by block number) Chemical agent Censor criteria Purity of the agent Statistical samples 20. ABSTRACT (Continue on reverse side U... chemical agent lots. Volume II (CONF) contains an analysis fo the operational capability as the 105rom MIOIAI and M102 Hpwltzej^g, DD , FORM JAN 73...Data Entered) CONTENTS Page Procedure for Determining the Serviceability Category of Chemical Agent Lots •• 5 User’s Guide to the Computer

Archaeology: site studies, activation analysis, preservation, and remote sensing. 1978-November 1979 (citations from the NTIS Data Base). Report for 1978-November 1979

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

Not Available

1981-01-01

This bibliography contains general studies as well as chemical analysis of archaeological specimens. The chemical analysis is mainly activation analysis of articles such as metals, pottery, coins, paintings, soils, glass and paper from Medieval, Grecian, Egyptian, Mayan, and prehistoric times. The general studies include results of excavation from the United States. Also covered is work on preservation of artifacts and remote sensing for the site location. (This updated bibliography contains 237 citations, none of which are new entries to the previous edition.)

Archaeological Investigations at Lakeview Lake: 1979 and 1980.

DTIC Science & Technology

1982-12-01

hnology Human ecology Soil chemical analysis * Terrace geology Archaeological Investigations at Lakeview Lake: * 1979 and 1980 Archaeological Monographs...Borrow Areas 47 5 Prehistoric Lithic Technology in the Lakeview Project 53 6 Chemical Analysis of Anthropic Soils 69 7 Prehistoric Human Ecology and...to Historical Site Analysis Bonnie C. Yates 287 Bibliography 293 ,’.: ’ : - . " : ’ "’" ".- - : ’ "" "’" ’ .’: : .- :,-"- * .:- i’ "c "-"’ b

Fourier transform infrared spectroscopy for analysis of kidney stones.

PubMed

Khan, Aysha Habib; Imran, Sheharbano; Talati, Jamsheer; Jafri, Lena

2018-01-01

To compare the results of a chemical method of kidney stone analysis with the results of Fourier transform infrared (FT-IR) spectroscopy. Kidney stones collected between June and October 2015 were simultaneously analyzed by chemical and FT-IR methods. Kidney stones (n=449) were collected from patients from 1 to 81 years old. Most stones were from adults, with only 11.5% from children (aged 3-16 years) and 1.5% from children aged <2 years. The male to female ratio was 4.6. In adults, the calcium oxalate stone type, calcium oxalate monohydrate (COM, n=224), was the most common crystal, followed by uric acid and calcium oxalate dihydrate (COD, n=83). In children, the most frequently occurring type was predominantly COD (n=21), followed by COM (n=11), ammonium urate (n=10), carbonate apatite (n=6), uric acid (n=4), and cystine (n=1). Core composition in 22 stones showed ammonium urate (n=2), COM (n=2), and carbonate apatite (n=1) in five stones, while uric acid crystals were detected (n=13) by FT-IR. While chemical analysis identified 3 stones as uric acid and the rest as calcium oxalate only. Agreement between the two methods was moderate, with a kappa statistic of 0.57 (95% confidence interval, 0.5-0.64). Disagreement was noted in the analysis of 77 stones. FT-IR analysis of kidney stones can overcome many limitations associated with chemical analysis.

Reducing Future International Chemical and Biological Dangers.

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

Haddal, Chad; Bull, Diana L.; Hernandez, Patricia Marie

The International Biological and Chemical Threat Reduction Program at Sandia National Laboratories is developing a 15 - year technology road map in support the United States Government efforts to reduce international chemical and biological dangers . In 2017, the program leadership chartered an analysis team to explore dangers in the future international chemical and biological landscape through engagements with national security experts within and beyond Sandia to gain a multidisciplinary perspective on the future . This report offers a hi gh level landscape of future chemical and biological dangers based upon analysis of those engagements and provides support for furthermore » technology road map development.« less

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

Rapid characterization of chemical markers for discrimination of Moutan Cortex and its processed products by direct injection-based mass spectrometry profiling and metabolomic method.

PubMed

Li, Chao-Ran; Li, Meng-Ning; Yang, Hua; Li, Ping; Gao, Wen

2018-06-01

Processing of herbal medicines is a characteristic pharmaceutical technique in Traditional Chinese Medicine, which can reduce toxicity and side effect, improve the flavor and efficacy, and even change the pharmacological action entirely. It is significant and crucial to perform a method to find chemical markers for differentiating herbal medicines in different processed degrees. The aim of this study was to perform a rapid and reasonable method to discriminate Moutan Cortex and its processed products, and to reveal the characteristics of chemical components depend on chemical markers. Thirty batches of Moutan Cortex and its processed products, including 11 batches of Raw Moutan Cortex (RMC), 9 batches of Moutan Cortex Tostus (MCT) and 10 batches of Moutan Cortex Carbonisatus (MCC), were directly injected in electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOF MS) for rapid analysis in positive and negative mode. Without chromatographic separation, each run was completed within 3 min. The raw MS data were automatically extracted by background deduction and molecular feature (MF) extraction algorithm. In negative mode, a total of 452 MFs were obtained and then pretreated by data filtration and differential analysis. After that, the filtered 85 MFs were treated by principal component analysis (PCA) to reduce the dimensions. Subsequently, a partial least squares discrimination analysis (PLS-DA) model was constructed for differentiation and chemical markers detection of Moutan Cortex in different processed degrees. The positive mode data were treated as same as those in negative mode. RMC, MCT and MCC were successfully classified. Moreover, 14 and 3 chemical markers from negative and positive mode respectively, were screened by the combination of their relative peak areas and the parameter variable importance in the projection (VIP) values in PLS-DA model. The content changes of these chemical markers were employed in order to illustrate chemical changes of Moutan Cortex after processed. These results showed that the proposed method which combined non-targeted metabolomics analysis with multivariate statistics analysis is reasonable and effective. It could not only be applied to discriminate herbal medicines and their processing products, but also to reveal the characteristics of chemical components during processing. Copyright © 2018. Published by Elsevier GmbH.

Prognostic Analysis System and Methods of Operation

NASA Technical Reports Server (NTRS)

MacKey, Ryan M. E. (Inventor); Sneddon, Robert (Inventor)

2014-01-01

A prognostic analysis system and methods of operating the system are provided. In particular, a prognostic analysis system for the analysis of physical system health applicable to mechanical, electrical, chemical and optical systems and methods of operating the system are described herein.

Analysis of Pfizer compounds in EPA's ToxCast chemicals-assay space.

PubMed

Shah, Falgun; Greene, Nigel

2014-01-21

The U.S. Environmental Protection Agency (EPA) launched the ToxCast program in 2007 with the goal of evaluating high-throughput in vitro assays to prioritize chemicals that need toxicity testing. Their goal was to develop predictive bioactivity signatures for toxic compounds using a set of in vitro assays and/or in silico properties. In 2009, Pfizer joined the ToxCast initiative by contributing 52 compounds with preclinical and clinical data for profiling across the multiple assay platforms available. Here, we describe the initial analysis of the Pfizer subset of compounds within the ToxCast chemical (n = 1814) and in vitro assay (n = 486) space. An analysis of the hit rate of Pfizer compounds in the ToxCast assay panel allowed us to focus our mining of assays potentially most relevant to the attrition of our compounds. We compared the bioactivity profile of Pfizer compounds to other compounds in the ToxCast chemical space to gain insights into common toxicity pathways. Additionally, we explored the similarity in the chemical and biological spaces between drug-like compounds and environmental chemicals in ToxCast and compared the in vivo profiles of a subset of failed pharmaceuticals having high similarity in both spaces. We found differences in the chemical and biological spaces of pharmaceuticals compared to environmental chemicals, which may question the applicability of bioactivity signatures developed exclusively based on the latter to drug-like compounds if used without prior validation with the ToxCast Phase-II chemicals. Finally, our analysis has allowed us to identify novel interactions for our compounds in particular with multiple nuclear receptors that were previously not known. This insight may help us to identify potential liabilities with future novel compounds.

Nonradiological chemical pathway analysis and identification of chemicals of concern for environmental monitoring at the Hanford Site

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

Blanton, M.L.; Cooper, A.T.; Castleton, K.J.

1995-11-01

Pacific Northwest`s Surface Environmental Surveillance Project (SESP) is an ongoing effort tot design, review, and conducted monitoring on and off the Hanford site. Chemicals of concern that were selected are listed. Using modeled exposure pathways, the offsite cancer incidence and hazard quotient were calculated and a retrospective pathway analysis performed to estimate what onsite concentrations would be required in the soil for each chemical of concern and other detected chemicals that would be required to obtain an estimated offsite human-health risk of 1.0E-06 cancer incidence or 1.0 hazard quotient. This analysis indicates that current nonradiological chemical contamination occurring on themore » site does not pose a significant offsite human-health risk; the highest cancer incidence to the offsite maximally exposed individual was from arsenic (1.76E-10); the highest hazard quotient was chromium(VI) (1.48E-04). The most sensitive pathways of exposure were surfacewater and aquatic food consumption. Combined total offsite excess cancer incidence was 2.09E-10 and estimated hazard quotient was 2.40E-04. Of the 17 identified chemicals of concern, the SESP does not currently (routinely) monitor arsenic, benzo(a)pyrene, bis(2- ethylhexyl)phthalate (BEHP), and chrysene. Only 3 of the chemicals of concern (arsenic, BEHP, chloroform) could actually occur in onsite soil at concern high enough to cause a 1.0E-06 excess cancer incidence or a 1.0 hazard index for a given offsite exposure pathway. During the retrospective analysis, 20 other chemicals were also evaluated; only vinyl chloride and thallium could reach targeted offsite risk values.« less

Solutions of the chemical kinetic equations for initially inhomogeneous mixtures.

NASA Technical Reports Server (NTRS)

Hilst, G. R.

1973-01-01

Following the recent discussions by O'Brien (1971) and Donaldson and Hilst (1972) of the effects of inhomogeneous mixing and turbulent diffusion on simple chemical reaction rates, the present report provides a more extensive analysis of when inhomogeneous mixing has a significant effect on chemical reaction rates. The analysis is then extended to the development of an approximate chemical sub-model which provides much improved predictions of chemical reaction rates over a wide range of inhomogeneities and pathological distributions of the concentrations of the reacting chemical species. In particular, the development of an approximate representation of the third-order correlations of the joint concentration fluctuations permits closure of the chemical sub-model at the level of the second-order moments of these fluctuations and the mean concentrations.

CERENA: ChEmical REaction Network Analyzer--A Toolbox for the Simulation and Analysis of Stochastic Chemical Kinetics.

PubMed

Kazeroonian, Atefeh; Fröhlich, Fabian; Raue, Andreas; Theis, Fabian J; Hasenauer, Jan

2016-01-01

Gene expression, signal transduction and many other cellular processes are subject to stochastic fluctuations. The analysis of these stochastic chemical kinetics is important for understanding cell-to-cell variability and its functional implications, but it is also challenging. A multitude of exact and approximate descriptions of stochastic chemical kinetics have been developed, however, tools to automatically generate the descriptions and compare their accuracy and computational efficiency are missing. In this manuscript we introduced CERENA, a toolbox for the analysis of stochastic chemical kinetics using Approximations of the Chemical Master Equation solution statistics. CERENA implements stochastic simulation algorithms and the finite state projection for microscopic descriptions of processes, the system size expansion and moment equations for meso- and macroscopic descriptions, as well as the novel conditional moment equations for a hybrid description. This unique collection of descriptions in a single toolbox facilitates the selection of appropriate modeling approaches. Unlike other software packages, the implementation of CERENA is completely general and allows, e.g., for time-dependent propensities and non-mass action kinetics. By providing SBML import, symbolic model generation and simulation using MEX-files, CERENA is user-friendly and computationally efficient. The availability of forward and adjoint sensitivity analyses allows for further studies such as parameter estimation and uncertainty analysis. The MATLAB code implementing CERENA is freely available from http://cerenadevelopers.github.io/CERENA/.

An extended chemical analysis of gallstone.

PubMed

Chandran, P; Kuchhal, N K; Garg, P; Pundir, C S

2007-09-01

Chemical composition of gall stones is essential for aetiopathogensis of gallstone disease. We have reported quantitative chemical analysis of total cholesterol bilirubin, calcium, iron and inorganic phosphate in 120 gallstones from haryana. To extend this chemical analysis of gall stones by studying more cases and by analyzing more chemical constituents. A quantitative chemical analysis of total cholesterol, total bilirubin, fatty acids, triglycerides, phospholipids, bile acids, soluble proteins, sodium potassium, magnesium, copper, oxalate and chlorides of biliary calculi (52 cholesterol, 76 mixed and 72 pigment) retrieved from surgical operation of 200 patients from Haryana state was carried out. Total cholesterol as the major component and total bilirubin, phospholipids, triglycerides, bile acids, fatty acids (esterified), soluble protein, calcium, magnesium, iron, copper, sodium, potassium, inorganic phosphate, oxalate and chloride as minor components were found in all types of calculi. The cholesterol stones had higher content of total cholesterol, phospholipids, fatty acids (esterified), inorganic phosphate and copper compared to mixed and pigment stones. The mixed stones had higher content of iron and triglycerides than to cholesterol and pigment stones. The pigment stones were richer in total bilirubin, bile acids, calcium, oxalate, magnesium, sodium, potassium, chloride and soluble protein compared to cholesterol and mixed stones. Although total cholesterol was a major component of cholesterol, mixed and pigment gall stone in Haryana, the content of most of the other lipids, cations and anions was different in different gall stones indicating their different mechanism of formation.

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.

LSENS: A General Chemical Kinetics and Sensitivity Analysis Code for homogeneous gas-phase reactions. Part 3: Illustrative test problems

NASA Technical Reports Server (NTRS)

Bittker, David A.; Radhakrishnan, Krishnan

1994-01-01

LSENS, the Lewis General Chemical Kinetics and Sensitivity Analysis Code, has been developed for solving complex, homogeneous, gas-phase chemical kinetics problems and contains sensitivity analysis for a variety of problems, including nonisothermal situations. This report is part 3 of a series of three reference publications that describe LSENS, provide a detailed guide to its usage, and present many example problems. Part 3 explains the kinetics and kinetics-plus-sensitivity analysis problems supplied with LSENS and presents sample results. These problems illustrate the various capabilities of, and reaction models that can be solved by, the code and may provide a convenient starting point for the user to construct the problem data file required to execute LSENS. LSENS is a flexible, convenient, accurate, and efficient solver for chemical reaction problems such as static system; steady, one-dimensional, inviscid flow; reaction behind incident shock wave, including boundary layer correction; and perfectly stirred (highly backmixed) reactor. In addition, the chemical equilibrium state can be computed for the following assigned states: temperature and pressure, enthalpy and pressure, temperature and volume, and internal energy and volume. For static problems the code computes the sensitivity coefficients of the dependent variables and their temporal derivatives with respect to the initial values of the dependent variables and/or the three rate coefficient parameters of the chemical reactions.

CERENA: ChEmical REaction Network Analyzer—A Toolbox for the Simulation and Analysis of Stochastic Chemical Kinetics

PubMed Central

Kazeroonian, Atefeh; Fröhlich, Fabian; Raue, Andreas; Theis, Fabian J.; Hasenauer, Jan

2016-01-01

Gene expression, signal transduction and many other cellular processes are subject to stochastic fluctuations. The analysis of these stochastic chemical kinetics is important for understanding cell-to-cell variability and its functional implications, but it is also challenging. A multitude of exact and approximate descriptions of stochastic chemical kinetics have been developed, however, tools to automatically generate the descriptions and compare their accuracy and computational efficiency are missing. In this manuscript we introduced CERENA, a toolbox for the analysis of stochastic chemical kinetics using Approximations of the Chemical Master Equation solution statistics. CERENA implements stochastic simulation algorithms and the finite state projection for microscopic descriptions of processes, the system size expansion and moment equations for meso- and macroscopic descriptions, as well as the novel conditional moment equations for a hybrid description. This unique collection of descriptions in a single toolbox facilitates the selection of appropriate modeling approaches. Unlike other software packages, the implementation of CERENA is completely general and allows, e.g., for time-dependent propensities and non-mass action kinetics. By providing SBML import, symbolic model generation and simulation using MEX-files, CERENA is user-friendly and computationally efficient. The availability of forward and adjoint sensitivity analyses allows for further studies such as parameter estimation and uncertainty analysis. The MATLAB code implementing CERENA is freely available from http://cerenadevelopers.github.io/CERENA/. PMID:26807911

Chemical data as markers of the geographical origins of sugarcane spirits.

PubMed

Serafim, F A T; Pereira-Filho, Edenir R; Franco, D W

2016-04-01

In an attempt to classify sugarcane spirits according to their geographic region of origin, chemical data for 24 analytes were evaluated in 50 cachaças produced using a similar procedure in selected regions of Brazil: São Paulo - SP (15), Minas Gerais - MG (11), Rio de Janeiro - RJ (11), Paraiba -PB (9), and Ceará - CE (4). Multivariate analysis was applied to the analytical results, and the predictive abilities of different classification methods were evaluated. Principal component analysis identified five groups, and chemical similarities were observed between MG and SP samples and between RJ and PB samples. CE samples presented a distinct chemical profile. Among the samples, partial linear square discriminant analysis (PLS-DA) classified 50.2% of the samples correctly, K-nearest neighbor (KNN) 86%, and soft independent modeling of class analogy (SIMCA) 56.2%. Therefore, in this proof of concept demonstration, the proposed approach based on chemical data satisfactorily predicted the cachaças' geographic origins. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

Study of Structural Morphology of Hemp Fiber from the Micro to the Nanoscale

NASA Astrophysics Data System (ADS)

Wang, Bei; Sain, Mohini; Oksman, Kristiina

2007-03-01

The focus of this work has been to study how high pressure defibrillation and chemical purification affect the hemp fiber morphology from micro to nanoscale. Microscopy techniques, chemical analysis and X-ray diffraction were used to study the structure and properties of the prepared micro and nanofibers. Microscopy studies showed that the used individualization processes lead to a unique morphology of interconnected web-like structure of hemp fibers. The nanofibers are bundles of cellulose fibers of widths ranging between 30 and 100 nm and estimated lengths of several micrometers. The chemical analysis showed that selective chemical treatments increased the α-cellulose content of hemp nanofibers from 75 to 94%. Fourier transform infrared spectroscopy (FTIR) study showed that the pectins were partially removed during the individualization treatments. X-ray analysis showed that the relative crystallinity of the studied fibers increased after each stage of chemical and mechanical treatments. It was also observed that the hemp nanofibers had an increased crystallinity of 71 from 57% of untreated hemp fibers.

Using a second‐order differential model to fit data without baselines in protein isothermal chemical denaturation

PubMed Central

Tang, Chuanning; Lew, Scott

2016-01-01

Abstract In vitro protein stability studies are commonly conducted via thermal or chemical denaturation/renaturation of protein. Conventional data analyses on the protein unfolding/(re)folding require well‐defined pre‐ and post‐transition baselines to evaluate Gibbs free‐energy change associated with the protein unfolding/(re)folding. This evaluation becomes problematic when there is insufficient data for determining the pre‐ or post‐transition baselines. In this study, fitting on such partial data obtained in protein chemical denaturation is established by introducing second‐order differential (SOD) analysis to overcome the limitations that the conventional fitting method has. By reducing numbers of the baseline‐related fitting parameters, the SOD analysis can successfully fit incomplete chemical denaturation data sets with high agreement to the conventional evaluation on the equivalent completed data, where the conventional fitting fails in analyzing them. This SOD fitting for the abbreviated isothermal chemical denaturation further fulfills data analysis methods on the insufficient data sets conducted in the two prevalent protein stability studies. PMID:26757366

Towards a nondestructive chemical characterization of biofilm matrix by Raman microscopy.

PubMed

Ivleva, Natalia P; Wagner, Michael; Horn, Harald; Niessner, Reinhard; Haisch, Christoph

2009-01-01

In this study, the applicability of Raman microscopy (RM) for nondestructive chemical analysis of biofilm matrix, including microbial constituents and extracellular polymeric substances (EPS), has been assessed. The examination of a wide range of reference samples such as biofilm-specific polysaccharides, proteins, microorganisms, and encapsulated bacteria revealed characteristic frequency regions and specific marker bands for different biofilm constituents. Based on received data, the assignment of Raman bands in spectra of multispecies biofilms was performed. The study of different multispecies biofilms showed that RM can correlate various structural appearances within the biofilm to variations in their chemical composition and provide chemical information about a complex biofilm matrix. The results of RM analysis of biofilms are in good agreement with data obtained by confocal laser scanning microscopy (CLSM). Thus, RM is a promising tool for a label-free chemical characterization of different biofilm constituents. Moreover, the combination of RM with CLSM analysis for the study of biofilms grown under different environmental conditions can provide new insights into the complex structure/function correlations in biofilms.

Analysis of baseline gene expression levels from toxicogenomics study control animals to identify sources of variation and predict responses to chemicals

EPA Science Inventory

The use of gene expression profiling to predict chemical mode of action would be enhanced by better characterization of variance due to individual, environmental, and technical factors. Meta-analysis of microarray data from untreated or vehicle-treated animals within the control ...

Fire in longleaf pine stand management: an economic analysis

Treesearch

Rodney L. Busby; Donald G. Hodges

1999-01-01

A simulation analysis of the economics of using prescribed fire as a forest management tool in the management of longleaf pine (Pinus palustris Mill.) plantations was conducted. A management regime using frequent prescribed fire was compared to management regimes involving fertilization and chemical release, chemical control, and mechanical control. Determining the...

ULg Spectra: An Interactive Software Tool to Improve Undergraduate Students' Structural Analysis Skills

ERIC Educational Resources Information Center

Agnello, Armelinda; Carre, Cyril; Billen, Roland; Leyh, Bernard; De Pauw, Edwin; Damblon, Christian

2018-01-01

The analysis of spectroscopic data to solve chemical structures requires practical skills and drills. In this context, we have developed ULg Spectra, a computer-based tool designed to improve the ability of learners to perform complex reasoning. The identification of organic chemical compounds involves gathering and interpreting complementary…

A Graphical Systems Model and Tissue-specific Functional Gene Sets to Aid Transcriptomic Analysis of Chemical Impacts on the Female Teleost Reproductive Axis

EPA Science Inventory

Oligonucleotide microarrays and other ‘omics’ approaches are powerful tools for unsupervised analysis of chemical impacts on biological systems. However, the lack of well annotated biological pathways for many aquatic organisms, including fish, and the poor power of microarray-b...

A modular Human Exposure Model (HEM) framework to characterize near-field chemical exposure in LCIA and CAA

EPA Science Inventory

Life Cycle Impact Analysis (LCIA) has proven to be a valuable tool for systematically comparing processes and products, and has been proposed for use in Chemical Alternatives Analysis (CAA). The exposure assessment portion of the human health impact scores of LCIA has historicall...

Silicon sheet growth development for the large area silicon sheet task of the low cost solar array project. Quantitative analysis of defects in silicon

NASA Technical Reports Server (NTRS)

Natesh, R.

1978-01-01

The various steps involved in obtaining quantitative information of structural defects in crystalline silicon samples are described. Procedures discussed include: (1) chemical polishing; (2) chemical etching; and (3) automated image analysis of samples on the QTM 720 System.

A review of promising new immunoassay technology for monitoring forest herbicides

Treesearch

Charles K. McMahon

1993-01-01

Rising costs of classical instrumental methods of chemical analysis coupled with an increasing need for environmental monitoring has lead to the development of highly sensitive, low-cost immunochemical methods of analysis for the detection of environmental contaminants. These methods known simply as immunoassays are chemical assays which use antibodies as reagents. A...

Results of the GCMS Effluent Gas Analysis for the Brine Processing Test

NASA Technical Reports Server (NTRS)

Delzeit, Lance; Lee, Jeffrey; Flynn, Michael; Fisher, John; Shaw, Hali; Kawashima, Brian; Beeler, David; Harris, Linden

2015-01-01

The effluent gas for the Paragon Ionomer Water Processor (IWP), UMPQUA Ultrasonic Brine Dewatering System (UBDS), and the NASA Brine Evaporation Bag (BEB) were analyzed using Headspace GCMS Analysis in the recent AES FY14 Brine Processing Test. The results from the analysis describe the number and general chemical species of the chemicals produced. Comparisons were also made between the different chromatograms for each system, and an explanation of the differences in the results is reported.

Analysis of the stochastic excitability in the flow chemical reactor

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

Bashkirtseva, Irina

2015-11-30

A dynamic model of the thermochemical process in the flow reactor is considered. We study an influence of the random disturbances on the stationary regime of this model. A phenomenon of noise-induced excitability is demonstrated. For the analysis of this phenomenon, a constructive technique based on the stochastic sensitivity functions and confidence domains is applied. It is shown how elaborated technique can be used for the probabilistic analysis of the generation of mixed-mode stochastic oscillations in the flow chemical reactor.

Analysis of the stochastic excitability in the flow chemical reactor

NASA Astrophysics Data System (ADS)

Bashkirtseva, Irina

2015-11-01

A dynamic model of the thermochemical process in the flow reactor is considered. We study an influence of the random disturbances on the stationary regime of this model. A phenomenon of noise-induced excitability is demonstrated. For the analysis of this phenomenon, a constructive technique based on the stochastic sensitivity functions and confidence domains is applied. It is shown how elaborated technique can be used for the probabilistic analysis of the generation of mixed-mode stochastic oscillations in the flow chemical reactor.

Analysis of Chemical, REP, and SEP missions to the Trojan asteroids

NASA Technical Reports Server (NTRS)

Bonfiglio, Eugene P.; Oh, David; Yen, Chen-Wan

2005-01-01

Recent studies suggest significant benefits from using 1st and 2nd generation Radioisotope Power Systems (RPS) as a power source for electric propulsion (EP) missions to the outer planets. This study focuses on trajectories to the Trojan asteroids. A high level analysis is performed with chemical trajectories to determine potential canidates for REP trajectory optimization. Extensive analysis of direct trajectories using REP is performed on these candidates. Solar Electric Propulsion (SEP) trajectories are also considered for comparison against REP trajectories.

Chemical, physical-chemical, and sensory characteristics of lychee (Litchi chinensis Sonn) wines.

PubMed

Alves, Juliana Alvarenga; de Oliveira Lima, Luiz Carlos; Nunes, Cleiton Antônio; Dias, Disney Ribeiro; Schwan, Rosane Freitas

2011-01-01

Four lychee (Litchi chinensis Sonn) wines (prepared with 3 yeast strains [UFLA CA11, UFLA CA1183, and UFLA CA1174]) and a spontaneous fermentation (SPON) were done in order to add value to the fruit while preventing waste arising from the short shelf life of lychee. The fermentation was monitored daily by analyzing the soluble solids, pH, acidity, ethanol, and sugar. At the end of fermentation, the wines were subjected to chemical, physical-chemical, and sensory analysis. The wines prepared showed greater variations in the qualitative than in the quantitative analysis of their constituents. The sensory analysis indicated that the wines fermented by yeast UFLA CA1183 and UFLA CA11 had rates of acceptance above 75%. The principal components analysis separated the wines into 2 groups according to the analyzed compounds. Based on these analyses, the wine produced by inoculation with UFLA CA1183 proved to be the most suitable for the production of lychee wines. Development of new products and adding value to fruits. Importance of selection of specific yeasts for production of fruit wine. © 2011 Institute of Food Technologists®

[Chemical-nutritional characterization of the moss Spagnum magellanicum].

PubMed

Villarroel, Mario; Biolley, Edith; Yáñez, Enrique; Peralta, Rosario

2002-12-01

The goal of the present study was to know the chemical characteristics of the moss Sphagnum magellanicum (S.M.) growing in the southern part of Chile, spreading approximately. in a geographic area of 500.000 Has. Very few antecedents are reported in the literature concerning the functional properties of this resource, with the exception of the water absorption and holding capacity. Many of the industrial or agricultural uses of this moss are strongly related with this characteristic. Looking for other alternatives of utilization, it has been planned its incorporation to staple foods as a source of dietary fiber. But first it is necessary to know its chemical characteristics Representative samples of this material were submitted to different chemical analysis such as proximal analysis, fractional fiber analysis and anti nutrient factors.. Results of those analysis show the high amount of dietary fiber founded in this resource (77%), higher than reported data for other traditional fiber sources such as lupin bran, rice hull, barley hull, oat bran, etc. Finally it is important emphasize the absence of antinutrient factor in this moss, that could make feasible its use for human nutrition.

Chemically-induced Mouse Lung Tumors: Applications to ...

EPA Pesticide Factsheets

A state-of-the-science workshop on chemically-induced mouse lung tumors was conducted by U.S. Environmental Protection Agency to better understand the mouse lung tumor data’s role in human health assessments. Three environmental chemicals - naphthalene, styrene, and ethylbenzene were chosen for the analysis due to the commonality of mouse lung tumors in all three chemicals. The goals of the workshop were to: identify the evidence, from multiple scientific disciplines, regarding formation of chemically-induced lung tumors in mice; discuss analysis and interpretation of the evidence; discuss how such evidence informs human health assessments; and identify commonalities, linkages, or differences between the evidence from various disciplines and across the chemicals. Evidence informing the association between occupational exposure to styrene, ethylbenzene, or naphthalene and lung cancer; comparative biology of mouse lung tumors, associated pathologic effects, issues related to tissue and species concordance; mode of action analysis and biological mechanisms including pharmacokinetics and pharmacodynamics; and evidence from cellular, genetic and molecular toxicity was discussed. In summary, although consensus was not sought, the panelists agreed that available mouse lung tumor data should be considered for human health risk evaluation on an individual chemical basis. Key data gaps were identified that would assist in further understanding the mechanism and relevan

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.

Stratospheric Sampling and In Situ Atmospheric Chemical Element Analysis During Meteor Showers: A Resource Study

NASA Technical Reports Server (NTRS)

Noever, David A.

2000-01-01

Resources studies for asteroidal mining evaluation have depended historically on remote sensing analysis for chemical elements. During the November 1998 Leonids meteor shower, a stratospheric balloon and various low-density capture media were used to sample fragments from Comet Tempel-Tuttle debris during a peak Earth crossing. The analysis not only demonstrates how potential sampling strategies may improve the projections for metals or rare elements in astromining, but also benchmarks materials during low temperature (-60 F), high dessication environments as seen during atmospheric exposure. The results indicate high aluminum, magnesium and iron content for various sampled particles recovered, but generalization to the sporadic meteors expected from asteroidal sources will require future improvements in larger sampling volumes before a broad-use strategy for chemical analysis can be described. A repeat of the experimental procedure is planned for the November 1999 Leonids' shower, and various improvements for atmospheric sampling will be discussed.

Model-based analysis of coupled equilibrium-kinetic processes: indirect kinetic studies of thermodynamic parameters using the dynamic data.

PubMed

Emami, Fereshteh; Maeder, Marcel; Abdollahi, Hamid

2015-05-07

Thermodynamic studies of equilibrium chemical reactions linked with kinetic procedures are mostly impossible by traditional approaches. In this work, the new concept of generalized kinetic study of thermodynamic parameters is introduced for dynamic data. The examples of equilibria intertwined with kinetic chemical mechanisms include molecular charge transfer complex formation reactions, pH-dependent degradation of chemical compounds and tautomerization kinetics in micellar solutions. Model-based global analysis with the possibility of calculating and embedding the equilibrium and kinetic parameters into the fitting algorithm has allowed the complete analysis of the complex reaction mechanisms. After the fitting process, the optimal equilibrium and kinetic parameters together with an estimate of their standard deviations have been obtained. This work opens up a promising new avenue for obtaining equilibrium constants through the kinetic data analysis for the kinetic reactions that involve equilibrium processes.

Automatic network coupling analysis for dynamical systems based on detailed kinetic models.

PubMed

Lebiedz, Dirk; Kammerer, Julia; Brandt-Pollmann, Ulrich

2005-10-01

We introduce a numerical complexity reduction method for the automatic identification and analysis of dynamic network decompositions in (bio)chemical kinetics based on error-controlled computation of a minimal model dimension represented by the number of (locally) active dynamical modes. Our algorithm exploits a generalized sensitivity analysis along state trajectories and subsequent singular value decomposition of sensitivity matrices for the identification of these dominant dynamical modes. It allows for a dynamic coupling analysis of (bio)chemical species in kinetic models that can be exploited for the piecewise computation of a minimal model on small time intervals and offers valuable functional insight into highly nonlinear reaction mechanisms and network dynamics. We present results for the identification of network decompositions in a simple oscillatory chemical reaction, time scale separation based model reduction in a Michaelis-Menten enzyme system and network decomposition of a detailed model for the oscillatory peroxidase-oxidase enzyme system.

High-sensitivity ESCA instrument

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

Davies, R.D.; Herglotz, H.K.; Lee, J.D.

1973-01-01

A new electron spectroscopy for chemical analysis (ESCA) instrument has been developed to provide high sensitivity and efficient operation for laboratory analysis of composition and chemical bonding in very thin surface layers of solid samples. High sensitivity is achieved by means of the high-intensity, efficient x-ray source described by Davies and Herglotz at the 1968 Denver X-Ray Conference, in combination with the new electron energy analyzer described by Lee at the 1972 Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. A sample chamber designed to provide for rapid introduction and replacement of samples has adequate facilities for various sample treatmentsmore » and conditiouing followed immediately by ESCA analysis of the sample. Examples of application are presented, demonstrating the sensitivity and resolution achievable with this instrument. Its usefulness in trace surface analysis is shown and some chemical shifts'' measured by the instrument are compared with those obtained by x-ray spectroscopy. (auth)« less

International Research Project on the Effects of Chemical Ageing of Polymers on Performance Properties: Chemical and Thermal Analysis

NASA Technical Reports Server (NTRS)

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

1996-01-01

Work during the past six months has included significant research in several areas aimed at further clarification of the aging and chemical failure mechanism of thermoplastics (PVDF or Tefzel) pipes. Among the areas investigated were the crystallinity changes associated with both the Coflon and Tefzel after various simulated environmental exposures using X-ray diffraction analysis. We have found that significant changes in polymer crystallinity levels occur as a function of the exposures. These crystallinity changes may have important consequences on the fracture, fatigue, tensile, and chemical resistance of the materials. We have also noted small changes in the molecular weight distribution. Again these changes may result in variations in the mechanical and chemical properties in the material. We conducted numerous analytical studies with methods including X-ray Diffraction, Gel Permeation Chromatography, Fourier Transform Infrared Spectroscopy, Ultra- Violet Scanning Analysis, GC/Mass Spectrometry, Differential Scanning Calorimetry and Thermomechanical Analysis. In the ultra-violet analysis we noted the presence of an absorption band indicative of triene formation. We investigated a number of aged samples of both Tefzel and Coflon that were forwarded from MERL. We also cast films at SWT and subjected these films to a refluxing methanol 1% ethylene diamine solution. An updated literature search was conducted using Dialog and DROLLS to identify any new papers that may have been published in the open literature since the start of this project. The updated literature search and abstracts are contained in the Appendix section of this report.

Letters from China: A History of the Origins of the Chemical Analysis of Ceramics.

PubMed

Pollard, A M

2015-02-01

This paper is an attempt to document the early history of the quantitative chemical analysis of ceramic materials in Europe, with a specific interest in the analysis of archaeological ceramics. This inevitably leads to a study of the attempts made in Europe to imitate the miraculous material--porcelain--imported from China from the fourteenth century onwards. It is clear that before the end of the eighteenth century progress was made in this endeavor by systematic but essentially trial-and-error firing of various raw materials, culminating in the successful production of European porcelain by Böttger and von Tschirnhaus in 1709. Shortly after this, letters describing the Chinese manufacture of porcelain, and, more importantly, samples of raw and fired material, began to arrive in Europe from French Jesuit missionaries, which were subjected to intense study. Following the perfection of gravimetric methods of chemical analysis in the late eighteenth century, these Chinese samples, and samples of porcelain from various European factories, were regularly analysed, particularly by Brongniart at Sèvres. Similar work was carried out on English porcelain by Simeon Shaw and Sir Arthur Church. The origins of the chemical analysis of archaeological ceramics are still somewhat obscure, but must date to the late eighteenth or early nineteenth centuries, by the likes of Vauquelin and Chaptal.

Simultaneous dispersive liquid-liquid microextraction derivatisation and gas chromatography mass spectrometry analysis of subcritical water extracts of sweet and sour cherry stems.

PubMed

Švarc-Gajić, Jaroslava; Clavijo, Sabrina; Suárez, Ruth; Cvetanović, Aleksandra; Cerdà, Víctor

2018-03-01

Cherry stems have been used in traditional medicine mostly for the treatment of urinary tract infections. Extraction with subcritical water, according to its selectivity, efficiency and other aspects, differs substantially from conventional extraction techniques. The complexity of plant subcritical water extracts is due to the ability of subcritical water to extract different chemical classes of different physico-chemical properties and polarities in a single run. In this paper, dispersive liquid-liquid microextraction (DLLME) with simultaneous derivatisation was optimised for the analysis of complex subcritical water extracts of cherry stems to allow simple and rapid preparation prior to gas chromatography-mass spectrometry (GC-MS). After defining optimal extracting and dispersive solvents, the optimised method was used for the identification of compounds belonging to different chemical classes in a single analytical run. The developed sample preparation protocol enabled simultaneous extraction and derivatisation, as well as convenient coupling with GC-MS analysis, reducing the analysis time and number of steps. The applied analytical protocol allowed simple and rapid chemical screening of subcritical water extracts and was used for the comparison of subcritical water extracts of sweet and sour cherry stems. Graphical abstract DLLME GC MS analysis of cherry stem extracts obtained by subcritical water.

Program Helps To Determine Chemical-Reaction Mechanisms

NASA Technical Reports Server (NTRS)

Bittker, D. A.; Radhakrishnan, K.

1995-01-01

General Chemical Kinetics and Sensitivity Analysis (LSENS) computer code developed for use in solving complex, homogeneous, gas-phase, chemical-kinetics problems. Provides for efficient and accurate chemical-kinetics computations and provides for sensitivity analysis for variety of problems, including problems involving honisothermal conditions. Incorporates mathematical models for static system, steady one-dimensional inviscid flow, reaction behind incident shock wave (with boundary-layer correction), and perfectly stirred reactor. Computations of equilibrium properties performed for following assigned states: enthalpy and pressure, temperature and pressure, internal energy and volume, and temperature and volume. Written in FORTRAN 77 with exception of NAMELIST extensions used for input.

Preparation And Analysis Of Specimens Of Ablative Materials

NASA Technical Reports Server (NTRS)

Solomon, William C.

1994-01-01

Procedure for chemical analysis of specimens of silicone-based ablative thermal-insulation materials SLA-561 and MA25 involves acid digestion of specimens to prepare them for analysis by inductively-coupled-plasma/atomic-emission spectroscopy (ICP/AES). In comparison with atomic-absorption spectroscopy (AAS), ICP/AES is faster and more accurate than AAS. Results of analyses stored in data base, used to trace variations in concentrations of chemical elements in materials during long-term storage, and used in timely manner in investigations of failures. Acid-digestion portion of procedure applied to other thermal-insulation materials containing room-temperature-vulcanizing silicones and enables instrumental analysis of these materials.

Archaeology: site studies, activation analysis, preservation, and remote sensing. Volume 3. 1978-November 1979 (a bibliography with abstracts). Report for 1978-November 79

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

Cavagnaro, D.

1979-12-01

These citations of federally-funded research are divided into two parts; namely, a chemical analysis of archaeological specimens, and general studies. The chemical analysis section deals primarily with activation analysis. Articles examined include metals, pottery, coins, paintings, soils, glass, and paper from Medieval, Grecian, Egyptian, Mayan, and prehistoric times. The general studies section cites other archaeological research, including results of excavation from the United States. Also covered is work on preservation of artifacts and remote sensing for the site location. (This updated bibliography contains 237 abstracts, 149 of which are new entries to the previous edition.)

Archaeology: site studies, activation analysis, preservation, and remote sensing. December 1979-December 1980 (citations from the NTIS Data Base). Report for December 1970-December 1980

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

Not Available

1981-01-01

These citations of federally-funded research contains the chemical analysis of archaeological specimens, as well as general studies. The chemical analysis deals primarily with activation analysis. Articles examined include metals, pottery, coins, paintings, soils, glass, and paper from Medieval, Grecian, Egyptian, Mayan, and prehistoric times. The general studies cites other archaeological research, including results of excavation from the United States. Also covered is work on preservation of artifacts and remote sensing for the site location. (This updated bibliography contains 133 citations, all of which are new entries to the previous edition.)

Archaeology: site studies, activation analysis, preservation, and remote sensing. Volume 2. 1977 (a bibliography with abstracts). Report for 1977

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

Cavagnaro, D.

1979-12-01

The cited reports of Federally-funded research are divided into two parts: namely, a chemical analysis of archaeological specimens, and general studies. The chemical analysis section deals primarily with activation analysis. Artifacts examined include metals, pottery, coins, paintings, soils, glass, and paper from Medieval, Grecian, Egyptian, Mayan, and prehistoric times. The general studies section discusses other archaeological research, including results of excavation from the United States. Also covered is work on preservation of artifacts and remote sensing for the site location. (This updated bibliography contains 128 abstracts, none of which are new entries to the previous edition.)

Archaeology: site studies, activation analysis, preservation, and remote sensing. volume 2. 1977-november, 1978 (a bibliography with abstracts). Report for 1977-Nov 78

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

Cavagnaro, D.M.

1978-11-01

These citations of Federally-funded research are divided into two parts; namely, a chemical analysis of archaeological specimens, and general studies. The chemical analysis section deals primarily with activation analysis. Articles examined include metals, pottery, coins, paintings, soils, glass, and paper from Medieval, Grecian, Egyptian, Mayan and prehistoric times. The general studies section cites other archaeological research, including results of excavation from the United States. Also covered is work on preservation of artifacts and remote sensing for the site location. (This updated bibliography contains 209 abstracts, 141 of which are new entries to the previous edition.)

Mars Hybrid Propulsion System Trajectory Analysis. Part I; Crew Missions

NASA Technical Reports Server (NTRS)

Chai, Patrick R.; Merrill, Raymond G.; Qu, Min

2015-01-01

NASAs Human spaceflight Architecture team is developing a reusable hybrid transportation architecture in which both chemical and electric propulsion systems are used to send crew and cargo to Mars destinations such as Phobos, Deimos, the surface of Mars, and other orbits around Mars. By combining chemical and electrical propulsion into a single space- ship and applying each where it is more effective, the hybrid architecture enables a series of Mars trajectories that are more fuel-efficient than an all chemical architecture without significant increases in flight times. This paper provides the analysis of the interplanetary segments of the three Evolvable Mars Campaign crew missions to Mars using the hybrid transportation architecture. The trajectory analysis provides departure and arrival dates and propellant needs for the three crew missions that are used by the campaign analysis team for campaign build-up and logistics aggregation analysis. Sensitivity analyses were performed to investigate the impact of mass growth, departure window, and propulsion system performance on the hybrid transportation architecture. The results and system analysis from this paper contribute to analyses of the other human spaceflight architecture team tasks and feed into the definition of the Evolvable Mars Campaign.

Risk analysis for biological hazards: What we need to know about invasive species

USGS Publications Warehouse

Stohlgren, T.J.; Schnase, J.L.

2006-01-01

Risk analysis for biological invasions is similar to other types of natural and human hazards. For example, risk analysis for chemical spills requires the evaluation of basic information on where a spill occurs; exposure level and toxicity of the chemical agent; knowledge of the physical processes involved in its rate and direction of spread; and potential impacts to the environment, economy, and human health relative to containment costs. Unlike typical chemical spills, biological invasions can have long lag times from introduction and establishment to successful invasion, they reproduce, and they can spread rapidly by physical and biological processes. We use a risk analysis framework to suggest a general strategy for risk analysis for invasive species and invaded habitats. It requires: (1) problem formation (scoping the problem, defining assessment endpoints); (2) analysis (information on species traits, matching species traits to suitable habitats, estimating exposure, surveys of current distribution and abundance); (3) risk characterization (understanding of data completeness, estimates of the “potential” distribution and abundance; estimates of the potential rate of spread; and probable risks, impacts, and costs); and (4) risk management (containment potential, costs, and opportunity costs; legal mandates and social considerations and information science and technology needs).

Miniaturized flow injection analysis system

DOEpatents

Folta, James A.

1997-01-01

A chemical analysis technique known as flow injection analysis, wherein small quantities of chemical reagents and sample are intermixed and reacted within a capillary flow system and the reaction products are detected optically, electrochemically, or by other means. A highly miniaturized version of a flow injection analysis system has been fabricated utilizing microfabrication techniques common to the microelectronics industry. The microflow system uses flow capillaries formed by etching microchannels in a silicon or glass wafer followed by bonding to another wafer, commercially available microvalves bonded directly to the microflow channels, and an optical absorption detector cell formed near the capillary outlet, with light being both delivered and collected with fiber optics. The microflow system is designed mainly for analysis of liquids and currently measures 38.times.25.times.3 mm, but can be designed for gas analysis and be substantially smaller in construction.

Flow Injection Mass Spectral Fingerprints Demonstrate Chemical Differences in Rio Red Grapefruit with Respect to Year, Harvest Time, and Conventional versus Organic Farming

PubMed Central

Chen, Pei; Harnly, James M.; Lester, Gene E.

2013-01-01

Spectral fingerprints were acquired for Rio Red grapefruit using flow injection electrospray ionization with ion trap and time-of-flight mass spectrometry (FI-ESI-IT-MS and FI-ESI-TOF-MS). Rio Red grapefruits were harvested 3 times a year (early, mid, and late harvests) in 2005 and 2006 from conventionally and organically grown trees. Data analysis using analysis of variance principal component analysis (ANOVA-PCA) demonstrated that, for both MS systems, the chemical patterns were different as a function of farming mode (conventional vs organic), as well as growing year and time of harvest. This was visually obvious with PCA and was shown to be statistically significant using ANOVA. The spectral fingerprints provided a more inclusive view of the chemical composition of the grapefruit and extended previous conclusions regarding the chemical differences between conventionally and organically grown Rio Red grapefruit. PMID:20337420

Computational singular perturbation analysis of stochastic chemical systems with stiffness

NASA Astrophysics Data System (ADS)

Wang, Lijin; Han, Xiaoying; Cao, Yanzhao; Najm, Habib N.

2017-04-01

Computational singular perturbation (CSP) is a useful method for analysis, reduction, and time integration of stiff ordinary differential equation systems. It has found dominant utility, in particular, in chemical reaction systems with a large range of time scales at continuum and deterministic level. On the other hand, CSP is not directly applicable to chemical reaction systems at micro or meso-scale, where stochasticity plays an non-negligible role and thus has to be taken into account. In this work we develop a novel stochastic computational singular perturbation (SCSP) analysis and time integration framework, and associated algorithm, that can be used to not only construct accurately and efficiently the numerical solutions to stiff stochastic chemical reaction systems, but also analyze the dynamics of the reduced stochastic reaction systems. The algorithm is illustrated by an application to a benchmark stochastic differential equation model, and numerical experiments are carried out to demonstrate the effectiveness of the construction.

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.

Chemical Composition and Antioxidant Activities of Three Polysaccharide Fractions from Pine Cones

PubMed Central

Xu, Ren-Bo; Yang, Xin; Wang, Jing; Zhao, Hai-Tian; Lu, Wei-Hong; Cui, Jie; Cheng, Cui-Lin; Zou, Pan; Huang, Wei-Wei; Wang, Pu; Li, Wen-Jing; Hu, Xing-Long

2012-01-01

The traditional method of gas chromatography-mass spectrometry for monosaccharide component analysis with pretreatment of acetylation is described with slight modifications and verified in detail in this paper. It was then successfully applied to the quantitative analysis of component monosaccharides in polysaccharides extracted from the pine cones. The results demonstrated that the three pine cone polysaccharides all consisted of ribose, rhamnose, arabinose, xylose, mannose, glucose and galactose in different molar ratios. According to the recovery experiment, the described method was proved accurate and practical for the analysis of pine cone polysaccharides, meeting the need in the field of chemical analysis of Pinus plants. Furthermore; the chemical characteristics, such as neutral sugar, uronic acids, amino acids, molecular weights, and antioxidant activities of the polysaccharides were investigated by chemical and instrumental methods. The results showed that the chemical compositions of the polysaccharides differed from each other, especially in the content of neutral sugar and uronic acid. In the antioxidant assays, the polysaccharide fractions exhibited effective scavenging activities on ABTS radical and hydroxyl radical, with their antioxidant capabilities decreasing in the order of PKP > PAP > PSP. Therefore, although the polysaccharide fractions had little effect on superoxide radical scavenging, they still have potential to be developed as natural antioxidant agents in functional foods or medicine. PMID:23203063

Feminization and masculinization of western mosquitofish (Gambusia affinis) observed in rivers impacted by municipal wastewaters

PubMed Central

Huang, Guo-Yong; Liu, You-Sheng; Chen, Xiao-Wen; Liang, Yan-Qiu; Liu, Shuang-Shuang; Yang, Yuan-Yuan; Hu, Li-Xin; Shi, Wen-Jun; Tian, Fei; Zhao, Jian-Liang; Chen, Jun; Ying, Guang-Guo

2016-01-01

Municipal wastewaters have been known to contain various estrogens and androgens. Little is known about the joint action of these chemicals from wastewaters on fishes in the aquatic environment. The objectives of this study were to investigate the estrogenic and/or androgenic effects in wild mosquitofish (Gambusia affinis) of two effluent-impacted rivers in South China by determining morphological changes and hepatic mRNA expression levels of relevant genes such as vitellogenin (Vtg), estrogen receptor (ERα) and androgen receptors (ARα and ARβ), and to assess the linkages of those morphological changes and hepatic mRNA expression levels to the chemical concentrations measured by in vitro bioassays and chemical analysis. The results showed a significant induction of Vtg and ERα mRNA in the livers of the males and a gonopodium-like anal fin in the females collected at the majority of sites. Redundancy analysis and Pearson correlation analysis showed that the chemical concentrations obtained by in vitro bioassays and chemical analysis had significant correlations with some of the endpoints for the estrogenic and/or androgenic effects in mosquitofish. The findings from this study indicate that the estrogens and androgens present in the two rivers could cause the observed estrogenic and androgenic effects in mosquitofish. PMID:26876344

An efficient approach to identify different chemical markers between fibrous root and rhizome of Anemarrhena asphodeloides by ultra high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry with multivariate statistical analysis.

PubMed

Wang, Fang-Xu; Yuan, Jian-Chao; Kang, Li-Ping; Pang, Xu; Yan, Ren-Yi; Zhao, Yang; Zhang, Jie; Sun, Xin-Guang; Ma, Bai-Ping

2016-09-10

An ultra high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry approach coupled with multivariate statistical analysis was established and applied to rapidly distinguish the chemical differences between fibrous root and rhizome of Anemarrhena asphodeloides. The datasets of tR-m/z pairs, ion intensity and sample code were processed by principal component analysis and orthogonal partial least squares discriminant analysis. Chemical markers could be identified based on their exact mass data, fragmentation characteristics, and retention times. And the new compounds among chemical markers could be isolated rapidly guided by the ultra high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry and their definitive structures would be further elucidated by NMR spectra. Using this approach, twenty-four markers were identified on line including nine new saponins and five new steroidal saponins of them were obtained in pure form. The study validated this proposed approach as a suitable method for identification of the chemical differences between various medicinal parts in order to expand medicinal parts and increase the utilization rate of resources. Copyright © 2016 Elsevier B.V. All rights reserved.

Chemical Composition Analysis of Extracts from Ficus Hirta Using Supercritical Fluid

NASA Astrophysics Data System (ADS)

Deng, S. B.; Chen, J. P.; Chen, Y. Z.; Yu, C. Q.; Yang, Y.; Wu, S. H.; Chen, C. Z.

2018-05-01

Ficus hirta was extracted by supercritical carbon dioxide. The volatile chemical components of extracts were analyzed using gas chromatography-mass spectrometry (GC-MS). The percentage of products extracted by Supercritical Fluid Extraction(SFE) was 2.5%. Nineteen volatile compounds were identified. The main volatile components were Elemicin, Psoralen, Palmitic acid, Bergapten, α-Linolenic acid, Medicarpin, Retinoic Acid, Maackiain, and Squalene. The method is simple and quick, and can be used for the preliminary analysis of chemical constituents of supercritical extracts of Ficus hirta.

Real time chemical exposure and risk monitor

DOEpatents

Thrall, Karla D.; Kenny, Donald V.; Endres, George W. R.; Sisk, Daniel R.

1997-01-01

The apparatus of the present invention is a combination of a breath interface and an external exposure dosimeter interface to a chemical analysis device, all controlled by an electronic processor for quantitatively analyzing chemical analysis data from both the breath interface and the external exposure dosimeter for determining internal tissue dose. The method of the present invention is a combination of steps of measuring an external dose, measuring breath content, then analyzing the external dose and breath content and determining internal tissue dose.

Real time chemical exposure and risk monitor

DOEpatents

Thrall, K.D.; Kenny, D.V.; Endres, G.W.R.; Sisk, D.R.

1997-07-08

The apparatus of the present invention is a combination of a breath interface and an external exposure dosimeter interface to a chemical analysis device, all controlled by an electronic processor for quantitatively analyzing chemical analysis data from both the breath interface and the external exposure dosimeter for determining internal tissue dose. The method of the present invention is a combination of steps of measuring an external dose, measuring breath content, then analyzing the external dose and breath content and determining internal tissue dose. 7 figs.

Nanoliter hemolymph sampling and analysis of individual adult Drosophila melanogaster.

PubMed

Piyankarage, Sujeewa C; Featherstone, David E; Shippy, Scott A

2012-05-15

The fruit fly (Drosophila melanogaster) is an extensively used and powerful, genetic model organism. However, chemical studies using individual flies have been limited by the animal's small size. Introduced here is a method to sample nanoliter hemolymph volumes from individual adult fruit-flies for chemical analysis. The technique results in an ability to distinguish hemolymph chemical variations with developmental stage, fly sex, and sampling conditions. Also presented is the means for two-point monitoring of hemolymph composition for individual flies.

Assessing Plausibility of Tentative Chemical Identifications from Suspect Screening Analyses via Chemical Function

EPA Science Inventory

Suspect screening (SSA) and non-targeted analysis (NTA) have become increasingly useful methods for identifying chemicals in indoor environments, which is where many chemical exposures occur. However, the tentative chemical identifications from these analyses must be confirmed. T...

Method and apparatus for chemical and topographical microanalysis

NASA Technical Reports Server (NTRS)

Kossakovski, Dmitri A. (Inventor); Baldeschwieler, John D. (Inventor); Beauchamp, Jesse L. (Inventor)

2002-01-01

A scanning probe microscope is combined with a laser induced breakdown spectrometer to provide spatially resolved chemical analysis of the surface correlated with the surface topography. Topographical analysis is achieved by scanning a sharp probe across the sample at constant distance from the surface. Chemical analysis is achieved by the means of laser induced breakdown spectroscopy by delivering pulsed laser radiation to the sample surface through the same sharp probe, and consequent collection and analysis of emission spectra from plasma generated on the sample by the laser radiation. The method comprises performing microtopographical analysis of the sample with a scanning probe, selecting a scanned topological site on the sample, generating a plasma plume at the selected scanned topological site, and measuring a spectrum of optical emission from the plasma at the selected scanned topological site. The apparatus comprises a scanning probe, a pulsed laser optically coupled to the probe, an optical spectrometer, and a controller coupled to the scanner, laser and spectrometer for controlling the operation of the scanner, laser and spectrometer. The probe and scanner are used for topographical profiling the sample. The probe is also used for laser radiation delivery to the sample for generating a plasma plume from the sample. Optical emission from the plasma plume is collected and delivered to the optical spectrometer so that analysis of emission spectrum by the optical spectrometer allows for identification of chemical composition of the sample at user selected sites.

The Chemical Adventures of Sherlock Holmes: Mrs. Hudson's Golden Brooch

ERIC Educational Resources Information Center

Shaw, Ken

2009-01-01

This story is a chemical mystery with an emphasis on qualitative analysis, metallurgy, and gravimetric analysis. It is, as well, yet another article in the continuing series, created by Thomas Waddell and Thomas R. Rybolt, that presents a scientific problem in mystery format in the context of the popular and beloved characters of Sherlock Holmes…

Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

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

Meyer, Matthew W.

2013-01-01

This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include themore » inherently weak Raman cross section and susceptibility to fluorescence interference.« less

ISS Expeditions 16 Thru 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

This slide presentation reviews the results of the chemical analysis of the potable water supply from the International Space Station (ISS) expeditions 16 thru 20. Both Russian ground water and shuttle-transferred water are available for the use of the ISS crew's requirements. This is supplemented with condensate water and water form the Water Recovery System (WRS). An overview of the condensate H2O recovery system is given and the WRS is described and diagrammed. The water quality requirements, the handling, and analytical methods for the inorganic and organic tests are reviewed. The chemical analysis results for expeditions 16-20 archival water samples collected from the various water sources indicate that all of the ISS potable water supplies were acceptable for crew consumption.

Rapid detection of hazardous chemicals in textiles by direct analysis in real-time mass spectrometry (DART-MS).

PubMed

Antal, Borbála; Kuki, Ákos; Nagy, Lajos; Nagy, Tibor; Zsuga, Miklós; Kéki, Sándor

2016-07-01

Residues of chemicals on clothing products were examined by direct analysis in real-time (DART) mass spectrometry. Our experiments have revealed the presence of more than 40 chemicals in 15 different clothing items. The identification was confirmed by DART tandem mass spectrometry (MS/MS) experiments for 14 compounds. The most commonly detected hazardous substances were nonylphenol ethoxylates (NPEs), phthalic acid esters (phthalates), amines released by azo dyes, and quinoline derivates. DART-MS was able to detect NPEs on the skin of the person wearing the clothing item contaminated by NPE residuals. Automated data acquisition and processing method was developed and tested for the recognition of NPE residues thereby reducing the analysis time.

Liquid chromatography tandem mass spectrometry determination of chemical markers and principal component analysis of Vitex agnus-castus L. fruits (Verbenaceae) and derived food supplements.

PubMed

Mari, Angela; Montoro, Paola; Pizza, Cosimo; Piacente, Sonia

2012-11-01

A validated analytical method for the quantitative determination of seven chemical markers occurring in a hydroalcoholic extract of Vitex agnus-castus fruits by liquid chromatography electrospray triple quadrupole tandem mass spectrometry (LC/ESI/(QqQ)MSMS) is reported. To carry out a comparative study, five commercial food supplements corresponding to hydroalcoholic extracts of V. agnus-castus fruits were analysed under the same chromatographic conditions of the crude extract. Principal component analysis (PCA), based only on the variation of the amount of the seven chemical markers, was applied in order to find similarities between the hydroalcoholic extract and the food supplements. A second PCA analysis was carried out considering the whole spectroscopic data deriving from liquid chromatography electrospray linear ion trap mass spectrometry (LC/ESI/(LIT)MS) analysis. High similarity between the two PCA was observed, showing the possibility to select one of these two approaches for future applications in the field of comparative analysis of food supplements and quality control procedures. Copyright © 2012 Elsevier B.V. All rights reserved.

Discrimination Enhancement with Transient Feature Analysis of a Graphene Chemical Sensor.

PubMed

Nallon, Eric C; Schnee, Vincent P; Bright, Collin J; Polcha, Michael P; Li, Qiliang

2016-01-19

A graphene chemical sensor is subjected to a set of structurally and chemically similar hydrocarbon compounds consisting of toluene, o-xylene, p-xylene, and mesitylene. The fractional change in resistance of the sensor upon exposure to these compounds exhibits a similar response magnitude among compounds, whereas large variation is observed within repetitions for each compound, causing a response overlap. Therefore, traditional features depending on maximum response change will cause confusion during further discrimination and classification analysis. More robust features that are less sensitive to concentration, sampling, and drift variability would provide higher quality information. In this work, we have explored the advantage of using transient-based exponential fitting coefficients to enhance the discrimination of similar compounds. The advantages of such feature analysis to discriminate each compound is evaluated using principle component analysis (PCA). In addition, machine learning-based classification algorithms were used to compare the prediction accuracies when using fitting coefficients as features. The additional features greatly enhanced the discrimination between compounds while performing PCA and also improved the prediction accuracy by 34% when using linear discrimination analysis.

Scanning photoelectron microscope for nanoscale three-dimensional spatial-resolved electron spectroscopy for chemical analysis.

PubMed

Horiba, K; Nakamura, Y; Nagamura, N; Toyoda, S; Kumigashira, H; Oshima, M; Amemiya, K; Senba, Y; Ohashi, H

2011-11-01

In order to achieve nondestructive observation of the three-dimensional spatially resolved electronic structure of solids, we have developed a scanning photoelectron microscope system with the capability of depth profiling in electron spectroscopy for chemical analysis (ESCA). We call this system 3D nano-ESCA. For focusing the x-ray, a Fresnel zone plate with a diameter of 200 μm and an outermost zone width of 35 nm is used. In order to obtain the angular dependence of the photoelectron spectra for the depth-profile analysis without rotating the sample, we adopted a modified VG Scienta R3000 analyzer with an acceptance angle of 60° as a high-resolution angle-resolved electron spectrometer. The system has been installed at the University-of-Tokyo Materials Science Outstation beamline, BL07LSU, at SPring-8. From the results of the line-scan profiles of the poly-Si/high-k gate patterns, we achieved a total spatial resolution better than 70 nm. The capability of our system for pinpoint depth-profile analysis and high-resolution chemical state analysis is demonstrated. © 2011 American Institute of Physics

Development of the HS-SPME-GC-MS/MS method for analysis of chemical warfare agent and their degradation products in environmental samples.

PubMed

Nawała, Jakub; Czupryński, Krzysztof; Popiel, Stanisław; Dziedzic, Daniel; Bełdowski, Jacek

2016-08-24

After World War II approximately 50,000 tons of chemical weapons were dumped in the Baltic Sea by the Soviet Union under the provisions of the Potsdam Conference on Disarmament. These dumped chemical warfare agents still possess a major threat to the marine environment and to human life. Therefore, continue monitoring of these munitions is essential. In this work, we present the application of new solid phase microextraction fibers in analysis of chemical warfare agents and their degradation products. It can be concluded that the best fiber for analysis of sulfur mustard and its degradation products is butyl acrylate (BA), whereas for analysis of organoarsenic compounds and chloroacetophenone, the best fiber is a co-polymer of methyl acrylate and methyl methacrylate (MA/MMA). In order to achieve the lowest LOD and LOQ the samples should be divided into two subsamples. One of them should be analyzed using a BA fiber, and the second one using a MA/MMA fiber. When the fast analysis is required, the microextraction should be performed by use of a butyl acrylate fiber because the extraction efficiency of organoarsenic compounds for this fiber is acceptable. Next, we have elaborated of the HS-SPME-GC-MS/MS method for analysis of CWA degradation products in environmental samples using laboratory obtained fibers The analytical method for analysis of organosulfur and organoarsenic compounds was optimized and validated. The LOD's for all target chemicals were between 0.03 and 0.65 ppb. Then, the analytical method developed by us, was used for the analysis of sediment and pore water samples from the Baltic Sea. During these studies, 80 samples were analyzed. It was found that 25 sediments and 5 pore water samples contained CWA degradation products such as 1,4-dithiane, 1,4-oxathiane or triphenylarsine, the latter being a component of arsine oil. The obtained data is evidence that the CWAs present in the Baltic Sea have leaked into the general marine environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Discrete mathematical data analysis approach: a valuable assessment method for sustainable chemistry.

PubMed

Voigt, Kristina; Scherb, Hagen; Bruggemann, Rainer; Schramm, Karl-Werner

2013-06-01

Sustainable/Green Chemistry is a chemical philosophy encouraging the design of products and processes that reduce or eliminate the use and generation of hazardous substances. In this respect, metrical scientific disciplines like Chemometrics are important, because they indicate criteria for chemicals being hazardous or not. We demonstrated that sustainable principles in the disciplines Green Chemistry, Green Engineering, and Sustainability in Information Technology have main aspects in common. The use of non-hazardous chemicals or the more efficient use of chemical substances is one of these aspects. We take a closer look on the topic of the hazards of chemical substances. Our research focuses on data analyses concerning environmental chemicals named Persistent Organic Pollutants (POPs), which are found all over the world and pose a large risk to environment as well as to humans. The evaluation of the data is a major step in the elucidation of the danger of these chemicals. The data analysis method demonstrated here, is based on the theory of partially ordered sets and provides a generalized ranking. In our approach we investigate data sets of breast milk samples of women in Denmark, Finland, and Turkey which contained measurable levels of 20 POPs. The goal is twofold: On the one side the hazardous chemicals are to be identified and on the other side possible differences among the three nations should be detected, because in that case possible different uptake mechanisms may be supposed. The data analysis is performed by the free available software package PyHasse, written by the third author. We conclude that the data analysis method can well be applied for distinguishing between more or less dangerous existing chemicals. Furthermore, it should be used in sustainable chemistry in the same manner for detecting more and less sustainable chemicals. Copyright © 2013 Elsevier B.V. All rights reserved.

Chemical Abundance Measurements of Ultra-Faint Dwarf Galaxies Discovered by the Dark Energy Survey

NASA Astrophysics Data System (ADS)

Nagasawa, Daniel; Marshall, Jennifer L.; Simon, Joshua D.; Hansen, Terese; Li, Ting; Bernstein, Rebecca; Balbinot, Eduardo; Drlica-Wagner, Alex; Pace, Andrew; Strigari, Louis; Pellegrino, Craig; DePoy, Darren L.; Suntzeff, Nicholas; Bechtol, Keith; Dark Energy Suvey

2018-01-01

We present chemical abundance analysis results derived from high-resolution spectroscopy of ultra-faint dwarfs discovered by the Dark Energy Survey. Ultra-faint dwarf galaxies preserve a fossil record of the chemical abundance patterns imprinted by the first stars in the Universe. High-resolution spectroscopic observations of member stars in several recently discovered Milky Way satellites reveal a range of abundance patterns among ultra-faint dwarfs suggesting that star formation processes in the early Universe were quite diverse. The chemical content provides a glimpse not only of the varied nucleosynthetic processes and chemical history of the dwarfs themselves, but also the environment in which they were formed. We present the chemical abundance analysis of these objects and discuss possible explanations for the observed abundance patterns.

Evidence of temperature-dependent effects on the estrogenic response of fish: implications with regard to climate change.

PubMed

Brian, Jayne V; Harris, Catherine A; Runnalls, Tamsin J; Fantinati, Andrea; Pojana, Giulio; Marcomini, Antonio; Booy, Petra; Lamoree, Marja; Kortenkamp, Andreas; Sumpter, John P

2008-07-01

Chemical risk assessment is fraught with difficulty due to the problem of accounting for the effects of mixtures. In addition to the uncertainty arising from chemical-to-chemical interactions, it is possible that environmental variables, such as temperature, influence the biological response to chemical challenge, acting as confounding factors in the analysis of mixture effects. Here, we investigate the effects of temperature on the response of fish to a defined mixture of estrogenic chemicals. It was anticipated that the response to the mixture may be exacerbated at higher temperatures, due to an increase in the rate of physiological processing. This is a pertinent issue in view of global climate change. Fathead minnows (Pimephales promelas) were exposed to the mixture in parallel exposure studies, which were carried out at different temperatures (20 and 30 degrees C). The estrogenic response was characterised using an established assay, involving the analysis of the egg yolk protein, vitellogenin (VTG). Patterns of VTG gene expression were also analysed using real-time QPCR. The results revealed that there was no effect of temperature on the magnitude of the VTG response after 2 weeks of chemical exposure. However, the analysis of mixture effects at two additional time points (24 h and 7 days) revealed that the response was induced more rapidly at the higher temperature. This trend was apparent from the analysis of effects both at the molecular and biochemical level. Whilst this indicates that climatic effects on water temperature are not a significant issue with regard to the long-term risk assessment of estrogenic chemicals, the relevance of short-term effects is, as yet, unclear. Furthermore, analysis of the patterns of VTG gene expression versus protein induction gives an insight into the physiological mechanisms responsible for temperature-dependent effects on the reproductive phenology of species such as roach. Hence, the data contribute to our understanding of the implications of global climate change for wild fish populations.

Establishment of gold-quartz standard GQS-1

USGS Publications Warehouse

Millard, Hugh T.; Marinenko, John; McLane, John E.

1969-01-01

A homogeneous gold-quartz standard, GQS-1, was prepared from a heterogeneous gold-bearing quartz by chemical treatment. The concentration of gold in GQS-1 was determined by both instrumental neutron activation analysis and radioisotope dilution analysis to be 2.61?0.10 parts per million. Analysis of 10 samples of the standard by both instrumental neutron activation analysis and radioisotope dilution analysis failed to reveal heterogeneity within the standard. The precision of the analytical methods, expressed as standard error, was approximately 0.1 part per million. The analytical data were also used to estimate the average size of gold particles. The chemical treatment apparently reduced the average diameter of the gold particles by at least an order of magnitude and increased the concentration of gold grains by a factor of at least 4,000.

Analytical Methods for Chemical and Sensory Characterization of Scent-Markings in Large Wild Mammals: A Review

PubMed Central

Soso, Simone B.; Koziel, Jacek A.; Johnson, Anna; Lee, Young Jin; Fairbanks, W. Sue

2014-01-01

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. PMID:24603639

[A novel approach to NIR spectral quantitative analysis: semi-supervised least-squares support vector regression machine].

PubMed

Li, Lin; Xu, Shuo; An, Xin; Zhang, Lu-Da

2011-10-01

In near infrared spectral quantitative analysis, the precision of measured samples' chemical values is the theoretical limit of those of quantitative analysis with mathematical models. However, the number of samples that can obtain accurately their chemical values is few. Many models exclude the amount of samples without chemical values, and consider only these samples with chemical values when modeling sample compositions' contents. To address this problem, a semi-supervised LS-SVR (S2 LS-SVR) model is proposed on the basis of LS-SVR, which can utilize samples without chemical values as well as those with chemical values. Similar to the LS-SVR, to train this model is equivalent to solving a linear system. Finally, the samples of flue-cured tobacco were taken as experimental material, and corresponding quantitative analysis models were constructed for four sample compositions' content(total sugar, reducing sugar, total nitrogen and nicotine) with PLS regression, LS-SVR and S2 LS-SVR. For the S2 LS-SVR model, the average relative errors between actual values and predicted ones for the four sample compositions' contents are 6.62%, 7.56%, 6.11% and 8.20%, respectively, and the correlation coefficients are 0.974 1, 0.973 3, 0.923 0 and 0.948 6, respectively. Experimental results show the S2 LS-SVR model outperforms the other two, which verifies the feasibility and efficiency of the S2 LS-SVR model.

[Relativity of commercial specification of Menthae Herba based on chemical analysis].

PubMed

Ye, Dan; Zhao, Ming; Shao, Yang; Ouyang, Zhen; Peng, Hua-sheng; Han Bang-xing; Zhang, Wei-wan-qi; Gu, Xue-mei

2015-01-01

In order to compare the differences of 35 Menthae Herba samples collected on the market and at producing areas, the contents of six total terpenoids, the essential oil and chromatographic fingerprints were analyzed, which provided evidences for drawing up the commodity specifications and grading criteria of Menthae Herba. GC-MS method was used to analyze the chemical constituents of 35 different samples. The chromatographic fingerprints obtained by using GC were then evaluated by similarity analysis, hierarchical clustering analysis and principal component analysis. The relativity between the content of six terpenoids and the essential oil were studied. In this study, the chemical profiles of 35 samples from different producing areas had significant disparity. All samples collected in the report could be categorized into four chemical types, L-menthol, pulegone, carvone and L-menthone, but the chemical profiles had no relationship with the areas. The chromatographic fingerprints of the samples from different types were dissimilar, while the different producing areas were difficult to be separated. It was indicated that the content of volatile oil was positively correlated with the content of L-menthol and the sum of six total terpenoids. The content of the essential oil, L-menthol and the sum of six total terpenoids of Menthae Herba were considered as one of the commercial specifications and grading criteria. These results in the research could be helpful to draw up the commercial specification and grading criteria of Menthae Herba from a view of chemical information.

Chemical Analysis of Water-accommodated Fractions of Crude Oil Spills Using TIMS-FT-ICR MS.

PubMed

Benigni, Paolo; Marin, Rebecca; Sandoval, Kathia; Gardinali, Piero; Fernandez-Lima, Francisco

2017-03-03

Multiple chemical processes control how crude oil is incorporated into seawater and also the chemical reactions that occur overtime. Studying this system requires the careful preparation of the sample in order to accurately replicate the natural formation of the water-accommodated fraction that occurs in nature. Low-energy water-accommodated fractions (LEWAF) are carefully prepared by mixing crude oil and water at a set ratio. Aspirator bottles are then irradiated, and at set time points, the water is sampled and extracted using standard techniques. A second challenge is the representative characterization of the sample, which must take into consideration the chemical changes that occur over time. A targeted analysis of the aromatic fraction of the LEWAF can be performed using an atmospheric-pressure laser ionization source coupled to a custom-built trapped ion mobility spectrometry-Fourier transform-ion cyclotron resonance mass spectrometer (TIMS-FT-ICR MS). The TIMS-FT-ICR MS analysis provides high-resolution ion mobility and ultrahigh-resolution MS analysis, which further allow the identification of isomeric components by their collision cross-sections (CCS) and chemical formula. Results show that as the oil-water mixture is exposed to light, there is significant photo-solubilization of the surface oil into the water. Over time, the chemical transformation of the solubilized molecules takes place, with a decrease in the number of identifications of nitrogen- and sulfur-bearing species in favor of those with a greater oxygen content than were typically observed in the base oil.

Analysis of supersonic combustion flow fields with embedded subsonic regions

NASA Technical Reports Server (NTRS)

Dash, S.; Delguidice, P.

1972-01-01

The viscous characteristic analysis for supersonic chemically reacting flows was extended to include provisions for analyzing embedded subsonic regions. The numerical method developed to analyze this mixed subsonic-supersonic flow fields is described. The boundary conditions are discussed related to the supersonic-subsonic and subsonic-supersonic transition, as well as a heuristic description of several other numerical schemes for analyzing this problem. An analysis of shock waves generated either by pressure mismatch between the injected fluid and surrounding flow or by chemical heat release is also described.

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 prepared with high selectivity since the host composition is typically readily different comparing to that of the analysed objects. In depth chemical analysis (chemical profiling) is found in particularly helpful allowing relatively easy isolation of the chemical composition of the host from the investigated objects [6]. Hence, both he chemical analysis of the environment and microstructures can be derived. Analysis of the isotope compositions can be measured with high level of confidence, nevertheless, presence of cluster of similar masses can make sometimes this analysis difficult. Based on this work, we are confident that similar studies can be conducted in situ planetary surfaces delivering important chemical context and evidences on bio-relevant processes. [1] Summons et al., Astrobiology, 11, 157, 2011. [2] Wurz et al., Sol. Sys. Res. 46, 408, 2012. [3] Riedo et al., J. Anal. Atom. Spectrom. 28, 1256, 2013. [4] Riedo et al., J. Mass Spectrom.48, 1, 2013. [5] Tulej et al., Geostand. Geoanal. Res., 38, 423, 2014. [6] Grimaudo et al., Anal. Chem. 87, 2041, 2015 [7] Tulej et al., Astrobiology, 15, 1, 2015. [8] Neubeck et al., Int. J. Astrobiology, 15, 133, 2016.

X-ray texture analysis of paper coating pigments and the correlation with chemical composition analysis

NASA Astrophysics Data System (ADS)

Roine, J.; Tenho, M.; Murtomaa, M.; Lehto, V.-P.; Kansanaho, R.

2007-10-01

The present research experiments the applicability of x-ray texture analysis in investigating the properties of paper coatings. The preferred orientations of kaolin, talc, ground calcium carbonate, and precipitated calcium carbonate particles used in four different paper coatings were determined qualitatively based on the measured crystal orientation data. The extent of the orientation, namely, the degree of the texture of each pigment, was characterized quantitatively using a single parameter. As a result, the effect of paper calendering is clearly seen as an increase on the degree of texture of the coating pigments. The effect of calendering on the preferred orientation of kaolin was also evident in an independent energy dispersive spectrometer analysis on micrometer scale and an electron spectroscopy for chemical analysis on nanometer scale. Thus, the present work proves x-ray texture analysis to be a potential research tool for characterizing the properties of paper coating layers.

Miniaturized flow injection analysis system

DOEpatents

Folta, J.A.

1997-07-01

A chemical analysis technique known as flow injection analysis is described, wherein small quantities of chemical reagents and sample are intermixed and reacted within a capillary flow system and the reaction products are detected optically, electrochemically, or by other means. A highly miniaturized version of a flow injection analysis system has been fabricated utilizing microfabrication techniques common to the microelectronics industry. The microflow system uses flow capillaries formed by etching microchannels in a silicon or glass wafer followed by bonding to another wafer, commercially available microvalves bonded directly to the microflow channels, and an optical absorption detector cell formed near the capillary outlet, with light being both delivered and collected with fiber optics. The microflow system is designed mainly for analysis of liquids and currently measures 38{times}25{times}3 mm, but can be designed for gas analysis and be substantially smaller in construction. 9 figs.

40 CFR 265.402 - Waste analysis and trial tests.

Code of Federal Regulations, 2013 CFR

2013-07-01

... waste analysis and trial test, or the documented information, in the operating record of the facility.] ... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Waste analysis and trial tests. 265... DISPOSAL FACILITIES Chemical, Physical, and Biological Treatment § 265.402 Waste analysis and trial tests...

40 CFR 265.402 - Waste analysis and trial tests.

Code of Federal Regulations, 2014 CFR

2014-07-01

... waste analysis and trial test, or the documented information, in the operating record of the facility.] ... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Waste analysis and trial tests. 265... DISPOSAL FACILITIES Chemical, Physical, and Biological Treatment § 265.402 Waste analysis and trial tests...

40 CFR 265.402 - Waste analysis and trial tests.

Code of Federal Regulations, 2012 CFR

2012-07-01

... waste analysis and trial test, or the documented information, in the operating record of the facility.] ... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Waste analysis and trial tests. 265... DISPOSAL FACILITIES Chemical, Physical, and Biological Treatment § 265.402 Waste analysis and trial tests...

40 CFR 265.402 - Waste analysis and trial tests.

Code of Federal Regulations, 2010 CFR

2010-07-01

... waste analysis and trial test, or the documented information, in the operating record of the facility.] ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Waste analysis and trial tests. 265... DISPOSAL FACILITIES Chemical, Physical, and Biological Treatment § 265.402 Waste analysis and trial tests...

40 CFR 265.402 - Waste analysis and trial tests.

Code of Federal Regulations, 2011 CFR

2011-07-01

... waste analysis and trial test, or the documented information, in the operating record of the facility.] ... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Waste analysis and trial tests. 265... DISPOSAL FACILITIES Chemical, Physical, and Biological Treatment § 265.402 Waste analysis and trial tests...

40 CFR 265.13 - General waste analysis.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false General waste analysis. 265.13 Section... FACILITIES General Facility Standards § 265.13 General waste analysis. (a)(1) Before an owner or operator...(d), he must obtain a detailed chemical and physical analysis of a representative sample of the...

40 CFR 264.13 - General waste analysis.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false General waste analysis. 264.13 Section... Facility Standards § 264.13 General waste analysis. (a)(1) Before an owner or operator treats, stores, or... detailed chemical and physical analysis of a representative sample of the wastes. At a minimum, the...

A combined qualitative and quantitative procedure for the chemical analysis of urinary calculi

PubMed Central

Hodgkinson, A.

1971-01-01

A better understanding of the physico-chemical principles underlying the formation of calculus has led to a need for more precise information on the chemical composition of stones. A combined qualitative and quantitative procedure for the chemical analysis of urinary calculi which is suitable for routine use is presented. The procedure involves five simple qualitative tests followed by the quantitative determination of calcium, magnesium, inorganic phosphate, and oxalate. These data are used to calculate the composition of the stone in terms of calcium oxalate, apatite, and magnesium ammonium phosphate. Analytical results and derived values for five representative types of calculi are presented. PMID:5551382

Metabolomics based on liquid chromatography with mass spectrometry reveals the chemical difference in the stems and roots derived from Ephedra sinica.

PubMed

Lv, Mengying; Chen, Jiaqing; Gao, Yiqiao; Sun, Jianbo; Zhang, Qianqian; Zhang, Mohan; Xu, Fengguo; Zhang, Zunjian

2015-10-01

To better understand different traditional uses of the stems (known as Mahuang) and roots (known as Mahuanggen) of Ephedra sinica, their chemical difference should be investigated. In this study, an ultra-fast liquid chromatography coupled with ion trap time-of-flight mass spectrometry untargeted metabolomics approach was established to reveal global chemical difference between Mahuang and Mahuanggen. Clear separation was observed in scores plots of principal component analysis and orthogonal partial least squares-discriminant analysis. Twenty two chemical markers responsible for such separation were screened out and unambiguously/tentatively characterized. Then chemical markers of pharmacologically important ephedrine and pseudoephedrine were absolutely quantified using liquid chromatography coupled with tandem mass spectrometry under multiple reaction monitoring mode. The results showed that Mahuang was rich in ephedrine-type alkaloids, while Mahuanggen was rich in macrocyclic spermine alkaloids. Additionally, different types of flavan-3-ols and flavones exist in Mahuang and Mahuanggen extracts. This research facilitates a better understanding of different traditional uses of Mahuang and Mahuanggen and provides references for chemical analysis of other medicinal plants. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid determination of chemical composition and classification of bamboo fractions using visible-near infrared spectroscopy coupled with multivariate data analysis.

PubMed

Yang, Zhong; Li, Kang; Zhang, Maomao; Xin, Donglin; Zhang, Junhua

2016-01-01

During conversion of bamboo into biofuels and chemicals, it is necessary to efficiently predict the chemical composition and digestibility of biomass. However, traditional methods for determination of lignocellulosic biomass composition are expensive and time consuming. In this work, a novel and fast method for quantitative and qualitative analysis of chemical composition and enzymatic digestibilities of juvenile bamboo and mature bamboo fractions (bamboo green, bamboo timber, bamboo yellow, bamboo node, and bamboo branch) using visible-near infrared spectra was evaluated. The developed partial least squares models yielded coefficients of determination in calibration of 0.88, 0.94, and 0.96, for cellulose, xylan, and lignin of bamboo fractions in raw spectra, respectively. After visible-near infrared spectra being pretreated, the corresponding coefficients of determination in calibration yielded by the developed partial least squares models are 0.994, 0.990, and 0.996, respectively. The score plots of principal component analysis of mature bamboo, juvenile bamboo, and different fractions of mature bamboo were obviously distinguished in raw spectra. Based on partial least squares discriminant analysis, the classification accuracies of mature bamboo, juvenile bamboo, and different fractions of bamboo (bamboo green, bamboo timber, bamboo yellow, and bamboo branch) all reached 100 %. In addition, high accuracies of evaluation of the enzymatic digestibilities of bamboo fractions after pretreatment with aqueous ammonia were also observed. The results showed the potential of visible-near infrared spectroscopy in combination with multivariate analysis in efficiently analyzing the chemical composition and hydrolysabilities of lignocellulosic biomass, such as bamboo fractions.

Comparison of sodium content of workplace and homemade meals through chemical analysis and salinity measurements.

PubMed

Shin, Eun-Kyung; Lee, Yeon-Kyung

2014-10-01

Most Koreans consume nearly 70-80% of the total sodium through their dishes. The use of a salinometer to measure salinity is recommended to help individuals control their sodium intake. The purpose of this study was to compare sodium content through chemical analysis and salinity measurement in foods served by industry foodservice operations and homemade meals. Workplace and homemade meals consumed by employees in 15 cafeterias located in 8 districts in Daegu were collected and the sodium content was measured through chemical analysis and salinity measurements and then compared. The foods were categorized into 9 types of menus with 103 workplace meals and 337 homemade meals. Workplace meals did not differ significantly in terms of sodium content per 100 g of food but had higher sodium content via chemical analysis in roasted foods per portion. Homemade meals had higher broth salt content and higher salt content by chemical analysis per 100 g of roasted foods and hard-boiled foods. One-dish workplace meals had higher salinity (P < 0.05), while homemade broths and stews had higher sodium content (P < 0.05 and P < 0.01, respectively). The sodium content per 100 g of foods was higher in one-dish workplace meals (P < 0.05) and in homemade broths and stews (P < 0.01 and P < 0.05, respectively). The use of a salinometer may be recommended to estimate the sodium content in foods and control one's sodium intake within the daily intake target as a way to promote cooking bland foods at home. However, estimated and actual measured values may differ.

Chemically-induced mouse lung tumors: applications to ...

EPA Pesticide Factsheets

A state-of-the-science workshop on chemically-induced mouse lung tumors was conducted by U.S. Environmental Protection Agency to discuss issues related to the use of mouse lung tumor data in human health assessments. Naphthalene, styrene, and ethylbenzene were chosen for the analysis due to the commonality of mouse lung tumors in all these three environmental chemicals. The goals of the workshop were to: identify the evidence, from multiple scientific disciplines, regarding formation of chemically-induced lung tumors in mice; discuss analysis and interpretation of the evidence; discuss how such evidence informs human health assessments; and identify commonalities, linkages, or differences between the evidence from various disciplines and across the chemicals. Evidence informing the association between occupational exposure to styrene, ethylbenzene, or naphthalene and lung cancer; comparative biology of mouse lung tumors, associated pathologic effects, issues related to tissue and species concordance; mode of action analysis and biological mechanisms including pharmacokinetics and pharmacodynamics; and evidence from cellular, genetic and molecular toxicity was discussed. In summary, although consensus was not sought, the panelists agreed that data showing mouse lung tumors with chemical exposures can be relevant for human health risk evaluation on an individual chemical basis. Key data gaps were identified that would assist in further understanding the mechanism

Micropyrolyzer for chemical analysis of liquid and solid samples

DOEpatents

Mowry, Curtis D.; Morgan, Catherine H.; Manginell, Ronald P.; Frye-Mason, Gregory C.

2006-07-18

A micropyrolyzer has applications to pyrolysis, heated chemistry, and thermal desorption from liquid or solid samples. The micropyrolyzer can be fabricated from semiconductor materials and metals using standard integrated circuit technologies. The micropyrolyzer enables very small volume samples of less than 3 microliters and high sample heating rates of greater than 20.degree. C. per millisecond. A portable analyzer for the field analysis of liquid and solid samples can be realized when the micropyrolyzer is combined with a chemical preconcentrator, chemical separator, and chemical detector. Such a portable analyzer can be used in a variety of government and industrial applications, such as non-proliferation monitoring, chemical and biological warfare detection, industrial process control, water and air quality monitoring, and industrial hygiene.

Evaluation of a semi-automated computer algorithm for measuring total fat and visceral fat content in lambs undergoing in vivo whole body computed tomography.

PubMed

Rosenblatt, Alana J; Scrivani, Peter V; Boisclair, Yves R; Reeves, Anthony P; Ramos-Nieves, Jose M; Xie, Yiting; Erb, Hollis N

2017-10-01

Computed tomography (CT) is a suitable tool for measuring body fat, since it is non-destructive and can be used to differentiate metabolically active visceral fat from total body fat. Whole body analysis of body fat is likely to be more accurate than single CT slice estimates of body fat. The aim of this study was to assess the agreement between semi-automated computer analysis of whole body volumetric CT data and conventional proximate (chemical) analysis of body fat in lambs. Data were collected prospectively from 12 lambs that underwent duplicate whole body CT, followed by slaughter and carcass analysis by dissection and chemical analysis. Agreement between methods for quantification of total and visceral fat was assessed by Bland-Altman plot analysis. The repeatability of CT was assessed for these measures using the mean difference of duplicated measures. When compared to chemical analysis, CT systematically underestimated total and visceral fat contents by more than 10% of the mean fat weight. Therefore, carcass analysis and semi-automated CT computer measurements were not interchangeable for quantifying body fat content without the use of a correction factor. CT acquisition was repeatable, with a mean difference of repeated measures being close to zero. Therefore, uncorrected whole body CT might have an application for assessment of relative changes in fat content, especially in growing lambs. Copyright © 2017 Elsevier Ltd. All rights reserved.

40 CFR 98.7 - What standardized methods are incorporated by reference into this part?

Code of Federal Regulations, 2012 CFR

2012-07-01

....astm.org. (1) ASTM C25-06 Standard Test Method for Chemical Analysis of Limestone, Quicklime, and....194(c), and § 98.334(b). (2) ASTM C114-09 Standard Test Methods for Chemical Analysis of Hydraulic... approved for § 98.6. (4) ASTM D240-02 (Reapproved 2007) Standard Test Method for Heat of Combustion of...

40 CFR 98.7 - What standardized methods are incorporated by reference into this part?

Code of Federal Regulations, 2013 CFR

2013-07-01

....astm.org. (1) ASTM C25-06 Standard Test Method for Chemical Analysis of Limestone, Quicklime, and....194(c), and § 98.334(b). (2) ASTM C114-09 Standard Test Methods for Chemical Analysis of Hydraulic... approved for § 98.6. (4) ASTM D240-02 (Reapproved 2007) Standard Test Method for Heat of Combustion of...

CHEMICAL ANALYSIS OF WORLD TRADE CENTER FINE PARTICULATE MATTER FOR USE IN TOXICOLOGICAL ASSESSMENT

EPA Science Inventory

Chemical Analysis of World Trade Center Fine Particulate Matter for Use in Toxicological Assessment
John K. McGee1, Lung Chi Chen2, Mitchell D. Cohen2, Glen R. Chee2, Colette M. Prophete2, Najwa Haykal-Coates1, Shirley J. Wasson3, Teri L. Conner4, Daniel L. Costa1, and Steph...

Gas chromatograph-mass spectrometer (GC/MS) system for quantitative analysis of reactive chemical compounds

DOEpatents

Grindstaff, Quirinus G.

1992-01-01

Described is a new gas chromatograph-mass spectrometer (GC/MS) system and method for quantitative analysis of reactive chemical compounds. All components of such a GC/MS system external to the oven of the gas chromatograph are programmably temperature controlled to operate at a volatilization temperature specific to the compound(s) sought to be separated and measured.

Expedition Six Flight Engineer Pettit uses a chemical/microbial analysis bag to collect water sample

NASA Image and Video Library

2002-12-18

ISS006-E-08628 (18 December 2002) --- Astronaut Donald R. Pettit, Expedition Six NASA ISS science officer, is pictured in the Zvezda Service Module on the International Space Station (ISS) during the scheduled Week 3 potable water sampling and on-orbit chemical/microbial analysis of the SM environment control and life support system.

Expedition Six Flight Engineer Pettit uses a chemical/microbial analysis bag to collect water sample

NASA Image and Video Library

2002-12-18

ISS006-E-08616 (18 December 2002) --- Astronaut Donald R. Pettit, Expedition Six NASA ISS science officer, is pictured in the Zvezda Service Module on the International Space Station (ISS) during the scheduled Week 3 potable water sampling and on-orbit chemical/microbial analysis of the SM environment control and life support system.

The Pharmaceutical Industry in 2016. An Analysis of FDA Drug Approvals from a Perspective of the Molecule Type.

PubMed

Torre, Beatriz G de la; Albericio, Fernando

2017-02-27

This is an analysis from a chemical point of view of the 22 drugs accepted by the FDA during 2016. The different drugs from the 2016 "harvest" have been classified according to their chemical structure: antibodies; TIDES (oligonucleotides and peptides); amino acids and natural products; drug combination; and small molecules.

Bibliography on Cold Regions Science and Technology. Volume 51, Part 1.

DTIC Science & Technology

1997-12-01

Loess, Plant ecology, Vegetation patterns, Revegeta- tion, Forestry, Soil conservation, Land reclamation, Regional planning, Statistical analysis...printing. Antikainen, M., Griffith, M., Zhang, J., Hon, W.C., Yang, D.S.C., Pihakaski-Maunsbach, K., Plant physi- ology. Mar. 1996, 110(1), p.845-857...65 refs. Plant physiology, Grasses, Plant tissues, Antifreezes, Acclimatization, Chemical analysis, Chemical prop- erties, Temperature effects

[Chemical and sensory characterization of tea (Thea sinensis) consumed in Chile].

PubMed

Wittig de Penna, Emma; José Zúñiga, María; Fuenzalida, Regina; López-Planes, Reinaldo

2005-03-01

By means of descriptive analysis four varieties of tea (Thea sinensis) were assesed: Argentinean OP (orange pekoe) tea (black), Brazilian OP tea (black), Ceylan OP tea (black) and Darjeeling OP tea (green). The appearance of dry tea leaves were qualitatively characterized comparing with dry leaves standard. The attributes: colour, form, regularity of the leaves, fibre and stem cutting were evaluated The differences obtained were related to the differences produced by the effect of the fermentation process. Flavour and aroma descriptors of the tea liqueur were generated by a trained panel. Colour and astringency were evaluated in comparison with qualified standards using non structured linear scales. In order to relate the sensory analysis and the chemical composition for the different varieties of tea, following determinations were made: chemical moisture, dry material, aqueous extract, tannin and caffeine. Through multifactor regression analysis the equations in relation to the following chemical parameters were determined. Dry material, aqueous extract and tannins for colour and moisture, dry material and aqueous extract for astringency, respectively. Statistical analysis through ANOVA (3 variation sources: samples, judges and replications) showed for samples four significant different groups for astringency and three different groups for colour. No significant differences between judges or repetitions were found. By multifactor regression analysis of both, colour and astringency, on their dependence of chemist results were calculated in order to asses the corresponding equations.

Provenance and depositional environment of epi-shelf lake sediment from Schirmacher Oasis, East Antarctica, vis-à-vis scanning electron microscopy of quartz grain, size distribution and chemical parameters

NASA Astrophysics Data System (ADS)

Shrivastava, Prakash K.; Asthana, Rajesh; Roy, Sandip K.; Swain, Ashit K.; Dharwadkar, Amit

2012-07-01

The scientific study of quartz grains is a powerful tool in deciphering the depositional environment and mode of transportation of sediments, and ultimately the origin and classification of sediments. Surface microfeatures, angularity, chemical features, and grain-size analysis of quartz grains, collectively reveal the sedimentary and physicochemical processes that acted on the grains during different stages of their geological history. Here, we apply scanning electron microscopic (SEM) analysis to evaluating the sedimentary provenance, modes of transport, weathering characteristics, alteration, and sedimentary environment of selected detrital quartz grains from the peripheral part of two epi-shelf lakes (ESL-1 and ESL-2) of the Schirmacher Oasis of East Antarctica. Our study reveals that different styles of physical weathering, erosive signatures, and chemical precipitation variably affected these quartz grains before final deposition as lake sediments. Statistical analysis (central tendencies, sorting, skewness, and kurtosis) indicates that these quartz-bearing sediments are poorly sorted glaciofluvial sediments. Saltation and suspension seem to have been the two dominant modes of transportation, and chemical analysis of these sediments indicates a gneissic provenance.

Preliminary Evaluation of a Regional Atmospheric Chemical Data Assimilation System for Environmental Surveillance

PubMed Central

Lee, Pius; Liu, Yang

2014-01-01

We report the progress of an ongoing effort by the Air Resources Laboratory, NOAA to build a prototype regional Chemical Analysis System (ARLCAS). The ARLCAS focuses on providing long-term analysis of the three dimensional (3D) air-pollutant concentration fields over the continental U.S. It leverages expertise from the NASA Earth Science Division-sponsored Air Quality Applied Science Team (AQAST) for the state-of-science knowledge in atmospheric and data assimilation sciences. The ARLCAS complies with national operational center requirement protocols and aims to have the modeling system to be maintained by a national center. Meteorology and chemistry observations consist of land-, air- and space-based observed and quality-assured data. We develop modularized testing to investigate the efficacies of the various components of the ARLCAS. The sensitivity testing of data assimilation schemes showed that with the increment of additional observational data sets, the accuracy of the analysis chemical fields also increased incrementally in varying margins. The benefit is especially noted for additional data sets based on a different platform and/or a different retrieval algorithm. We also described a plan to apply the analysis chemical fields in environmental surveillance at the Centers for Disease Control and Prevention. PMID:25514141

Fragrances and other materials in deodorants: search for potentially sensitizing molecules using combined GC-MS and structure activity relationship (SAR) analysis.

PubMed

Rastogi, S C; Lepoittevin, J P; Johansen, J D; Frosch, P J; Menné, T; Bruze, M; Dreier, B; Andersen, K E; White, I R

1998-12-01

Deodorants are one of the most frequently-used types of cosmetics and are a source of allergic contact dermatitis. Therefore, a gas chromatography - mass spectrometric analysis of 71 deodorants was performed for identification of fragrance and non-fragrance materials present in marketed deodorants. Futhermore, the sensitizing potential of these molecules was evaluated using structure activity relationships (SARs) analysis. This was based on the presence of 1 or more chemically reactive site(s), in the chemical structure, associated with sensitizing potential. Among the many different substances used to formulate cosmetic products (over 3500), 226 chemicals were identified in a sample of 71 deodorants. 84 molecules were found to contain at least 1 structural alert, and 70 to belong to, or be susceptible to being metabolized into, the chemical group of aldehydes, ketones and alpha,beta-unsaturated aldehydes, ketone or esters. The combination of GC-MS and SARs analysis could be helpful in the selection of substances for supplementary investigations regarding sensitizing properties. Thus, it may be a valuable tool in the management of contact allergy to deodorants and for producing new deodorants with decreased propensity to cause contact allergy.

Discriminant analysis of fused positive and negative ion mobility spectra using multivariate self-modeling mixture analysis and neural networks.

PubMed

Chen, Ping; Harrington, Peter B

2008-02-01

A new method coupling multivariate self-modeling mixture analysis and pattern recognition has been developed to identify toxic industrial chemicals using fused positive and negative ion mobility spectra (dual scan spectra). A Smiths lightweight chemical detector (LCD), which can measure positive and negative ion mobility spectra simultaneously, was used to acquire the data. Simple-to-use interactive self-modeling mixture analysis (SIMPLISMA) was used to separate the analytical peaks in the ion mobility spectra from the background reactant ion peaks (RIP). The SIMPLSIMA analytical components of the positive and negative ion peaks were combined together in a butterfly representation (i.e., negative spectra are reported with negative drift times and reflected with respect to the ordinate and juxtaposed with the positive ion mobility spectra). Temperature constrained cascade-correlation neural network (TCCCN) models were built to classify the toxic industrial chemicals. Seven common toxic industrial chemicals were used in this project to evaluate the performance of the algorithm. Ten bootstrapped Latin partitions demonstrated that the classification of neural networks using the SIMPLISMA components was statistically better than neural network models trained with fused ion mobility spectra (IMS).

Forensic applications of ambient ionization mass spectrometry.

PubMed

Ifa, Demian R; Jackson, Ayanna U; Paglia, Giuseppe; Cooks, R Graham

2009-08-01

This review highlights and critically assesses forensic applications in the developing field of ambient ionization mass spectrometry. Ambient ionization methods permit the ionization of samples outside the mass spectrometer in the ordinary atmosphere, with minimal sample preparation. Several ambient ionization methods have been created since 2004 and they utilize different mechanisms to create ions for mass-spectrometric analysis. Forensic applications of these techniques--to the analysis of toxic industrial compounds, chemical warfare agents, illicit drugs and formulations, explosives, foodstuff, inks, fingerprints, and skin--are reviewed. The minimal sample pretreatment needed is illustrated with examples of analysis from complex matrices (e.g., food) on various substrates (e.g., paper). The low limits of detection achieved by most of the ambient ionization methods for compounds of forensic interest readily offer qualitative confirmation of chemical identity; in some cases quantitative data are also available. The forensic applications of ambient ionization methods are a growing research field and there are still many types of applications which remain to be explored, particularly those involving on-site analysis. Aspects of ambient ionization currently undergoing rapid development include molecular imaging and increased detection specificity through simultaneous chemical reaction and ionization by addition of appropriate chemical reagents.

Preliminary evaluation of a regional atmospheric chemical data assimilation system for environmental surveillance.

PubMed

Lee, Pius; Liu, Yang

2014-12-01

We report the progress of an ongoing effort by the Air Resources Laboratory, NOAA to build a prototype regional Chemical Analysis System (ARLCAS). The ARLCAS focuses on providing long-term analysis of the three dimensional (3D) air-pollutant concentration fields over the continental U.S. It leverages expertise from the NASA Earth Science Division-sponsored Air Quality Applied Science Team (AQAST) for the state-of-science knowledge in atmospheric and data assimilation sciences. The ARLCAS complies with national operational center requirement protocols and aims to have the modeling system to be maintained by a national center. Meteorology and chemistry observations consist of land-, air- and space-based observed and quality-assured data. We develop modularized testing to investigate the efficacies of the various components of the ARLCAS. The sensitivity testing of data assimilation schemes showed that with the increment of additional observational data sets, the accuracy of the analysis chemical fields also increased incrementally in varying margins. The benefit is especially noted for additional data sets based on a different platform and/or a different retrieval algorithm. We also described a plan to apply the analysis chemical fields in environmental surveillance at the Centers for Disease Control and Prevention.

Chemical Fingerprint and Quantitative Analysis for the Quality Evaluation of Platycladi cacumen by Ultra-performance Liquid Chromatography Coupled with Hierarchical Cluster Analysis.

PubMed

Shan, Mingqiu; Li, Sam Fong Yau; Yu, Sheng; Qian, Yan; Guo, Shuchen; Zhang, Li; Ding, Anwei

2018-01-01

Platycladi cacumen (dried twigs and leaves of Platycladus orientalis (L.) Franco) is a frequently utilized Chinese medicinal herb. To evaluate the quality of the phytomedcine, an ultra-performance liquid chromatographic method with diode array detection was established for chemical fingerprinting and quantitative analysis. In this study, 27 batches of P. cacumen from different regions were collected for analysis. A chemical fingerprint with 20 common peaks was obtained using Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine (Version 2004A). Among these 20 components, seven flavonoids (myricitrin, isoquercitrin, quercitrin, afzelin, cupressuflavone, amentoflavone and hinokiflavone) were identified and determined simultaneously. In the method validation, the seven analytes showed good regressions (R ≥ 0.9995) within linear ranges and good recoveries from 96.4% to 103.3%. Furthermore, with the contents of these seven flavonoids, hierarchical clustering analysis was applied to distinguish the 27 batches into five groups. The chemometric results showed that these groups were almost consistent with geographical positions and climatic conditions of the production regions. Integrating fingerprint analysis, simultaneous determination and hierarchical clustering analysis, the established method is rapid, sensitive, accurate and readily applicable, and also provides a significant foundation for quality control of P. cacumen efficiently. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Digital image processing and analysis for activated sludge wastewater treatment.

PubMed

Khan, Muhammad Burhan; Lee, Xue Yong; Nisar, Humaira; Ng, Choon Aun; Yeap, Kim Ho; Malik, Aamir Saeed

2015-01-01

Activated sludge system is generally used in wastewater treatment plants for processing domestic influent. Conventionally the activated sludge wastewater treatment is monitored by measuring physico-chemical parameters like total suspended solids (TSSol), sludge volume index (SVI) and chemical oxygen demand (COD) etc. For the measurement, tests are conducted in the laboratory, which take many hours to give the final measurement. Digital image processing and analysis offers a better alternative not only to monitor and characterize the current state of activated sludge but also to predict the future state. The characterization by image processing and analysis is done by correlating the time evolution of parameters extracted by image analysis of floc and filaments with the physico-chemical parameters. This chapter briefly reviews the activated sludge wastewater treatment; and, procedures of image acquisition, preprocessing, segmentation and analysis in the specific context of activated sludge wastewater treatment. In the latter part additional procedures like z-stacking, image stitching are introduced for wastewater image preprocessing, which are not previously used in the context of activated sludge. Different preprocessing and segmentation techniques are proposed, along with the survey of imaging procedures reported in the literature. Finally the image analysis based morphological parameters and correlation of the parameters with regard to monitoring and prediction of activated sludge are discussed. Hence it is observed that image analysis can play a very useful role in the monitoring of activated sludge wastewater treatment plants.

Environmental epigenomics: Current approaches to assess epigenetic effects of endocrine disrupting compounds (EDC's) on human health.

PubMed

Tapia-Orozco, Natalia; Santiago-Toledo, Gerardo; Barrón, Valeria; Espinosa-García, Ana María; García-García, José Antonio; García-Arrazola, Roeb

2017-04-01

Environmental Epigenomics is a developing field to study the epigenetic effect on human health from exposure to environmental factors. Endocrine disrupting chemicals have been detected primarily in pharmaceutical drugs, personal care products, food additives, and food containers. Exposure to endocrine-disrupting chemicals (EDCs) has been associated with a high incidence and prevalence of many endocrine-related disorders in humans. Nevertheless, further evidence is needed to establish a correlation between exposure to EDC and human disorders. Conventional detection of EDCs is based on chemical structure and concentration sample analysis. However, substantial evidence has emerged, suggesting that cell exposure to EDCs leads to epigenetic changes, independently of its chemical structure with non-monotonic low-dose responses. Consequently, a paradigm shift in toxicology assessment of EDCs is proposed based on a comprehensive review of analytical techniques used to evaluate the epigenetic effects. Fundamental insights reported elsewhere are compared in order to establish DNA methylation analysis as a viable method for assessing endocrine disruptors beyond the conventional study approach of chemical structure and concentration analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Continuous-flow centrifugation to collect suspended sediment for chemical analysis

USGS Publications Warehouse

Conn, Kathleen E.; Dinicola, Richard S.; Black, Robert W.; Cox, Stephen E.; Sheibley, Richard W.; Foreman, James R.; Senter, Craig A.; Peterson, Norman T.

2016-12-22

Recent advances in suspended-sediment monitoring tools and surrogate technologies have greatly improved the ability to quantify suspended-sediment concentrations and to estimate daily, seasonal, and annual suspended-sediment fluxes from rivers to coastal waters. However, little is known about the chemical composition of suspended sediment, and how it may vary spatially between water bodies and temporally within a single system owing to climate, seasonality, land use, and other natural and anthropogenic drivers. Many water-quality contaminants, such as organic and inorganic chemicals, nutrients, and pathogens, preferentially partition in sediment rather than water. Suspended sediment-bound chemical concentrations may be undetected during analysis of unfiltered water samples, owing to small water sample volumes and analytical limitations. Quantification of suspended sediment‑bound chemical concentrations is needed to improve estimates of total chemical concentrations, chemical fluxes, and exposure levels of aquatic organisms and humans in receiving environments. Despite these needs, few studies or monitoring programs measure the chemical composition of suspended sediment, largely owing to the difficulty in consistently obtaining samples of sufficient quality and quantity for laboratory analysis.A field protocol is described here utilizing continuous‑flow centrifugation for the collection of suspended sediment for chemical analysis. The centrifuge used for development of this method is small, lightweight, and portable for the field applications described in this protocol. Project scoping considerations, deployment of equipment and system layout options, and results from various field and laboratory quality control experiments are described. The testing confirmed the applicability of the protocol for the determination of many inorganic and organic chemicals sorbed on suspended sediment, including metals, pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls. The particle-size distribution of the captured sediment changes to a more fine-grained sample during centrifugation, and the necessity to account for this change when extrapolating chemical concentrations on the centrifuged sediment sample to the environmental water system is discussed.The data produced using this method will help eliminate a data gap of suspended sediment-bound chemical concentrations, and will support management decisions, such as chemical source-control efforts or in-stream restoration activities. When coupled with streamflow and sediment flux data, it will improve estimates of riverine chemical fluxes, and will aid in assessing the importance and impacts of suspended sediment-bound chemicals to downstream freshwater and coastal marine ecosystems.

Software for analysis of chemical mixtures--composition, occurrence, distribution, and possible toxicity

USGS Publications Warehouse

Scott, Jonathon C.; Skach, Kenneth A.; Toccalino, Patricia L.

2013-01-01

The composition, occurrence, distribution, and possible toxicity of chemical mixtures in the environment are research concerns of the U.S. Geological Survey and others. The presence of specific chemical mixtures may serve as indicators of natural phenomena or human-caused events. Chemical mixtures may also have ecological, industrial, geochemical, or toxicological effects. Chemical-mixture occurrences vary by analyte composition and concentration. Four related computer programs have been developed by the National Water-Quality Assessment Program of the U.S. Geological Survey for research of chemical-mixture compositions, occurrences, distributions, and possible toxicities. The compositions and occurrences are identified for the user-supplied data, and therefore the resultant counts are constrained by the user’s choices for the selection of chemicals, reporting limits for the analytical methods, spatial coverage, and time span for the data supplied. The distribution of chemical mixtures may be spatial, temporal, and (or) related to some other variable, such as chemical usage. Possible toxicities optionally are estimated from user-supplied benchmark data. The software for the analysis of chemical mixtures described in this report is designed to work with chemical-analysis data files retrieved from the U.S. Geological Survey National Water Information System but can also be used with appropriately formatted data from other sources. Installation and usage of the mixture software are documented. This mixture software was designed to function with minimal changes on a variety of computer-operating systems. To obtain the software described herein and other U.S. Geological Survey software, visit http://water.usgs.gov/software/.

Tox21 Enricher: Web-based Chemical/Biological Functional Annotation Analysis Tool Based on Tox21 Toxicity Screening Platform.

PubMed

Hur, Junguk; Danes, Larson; Hsieh, Jui-Hua; McGregor, Brett; Krout, Dakota; Auerbach, Scott

2018-05-01

The US Toxicology Testing in the 21st Century (Tox21) program was established to develop more efficient and human-relevant toxicity assessment methods. The Tox21 program screens >10,000 chemicals using quantitative high-throughput screening (qHTS) of assays that measure effects on toxicity pathways. To date, more than 70 assays have yielded >12 million concentration-response curves. The patterns of activity across assays can be used to define similarity between chemicals. Assuming chemicals with similar activity profiles have similar toxicological properties, we may infer toxicological properties based on its neighbourhood. One approach to inference is chemical/biological annotation enrichment analysis. Here, we present Tox21 Enricher, a web-based chemical annotation enrichment tool for the Tox21 toxicity screening platform. Tox21 Enricher identifies over-represented chemical/biological annotations among lists of chemicals (neighbourhoods), facilitating the identification of the toxicological properties and mechanisms in the chemical set. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

DESIGN AND PERFORMANCE OF A XENOBIOTIC METABOLISM DATABASE MANAGER FOR METABOLIC SIMULATOR ENHANCEMENT AND CHEMICAL RISK ANALYSIS

EPA Science Inventory

A major uncertainty that has long been recognized in evaluating chemical toxicity is accounting for metabolic activation of chemicals resulting in increased toxicity. In silico approaches to predict chemical metabolism and to subsequently screen and prioritize chemicals for risk ...

Integrated photonics for infrared spectroscopic sensing

NASA Astrophysics Data System (ADS)

Lin, Hongtao; Kita, Derek; Han, Zhaohong; Su, Peter; Agarwal, Anu; Yadav, Anupama; Richardson, Kathleen; Gu, Tian; Hu, Juejun

2017-05-01

Infrared (IR) spectroscopy is widely recognized as a gold standard technique for chemical analysis. Traditional IR spectroscopy relies on fragile bench-top instruments located in dedicated laboratory settings, and is thus not suitable for emerging field-deployed applications such as in-line industrial process control, environmental monitoring, and point-ofcare diagnosis. Recent strides in photonic integration technologies provide a promising route towards enabling miniaturized, rugged platforms for IR spectroscopic analysis. Chalcogenide glasses, the amorphous compounds containing S, Se or Te, have stand out as a promising material for infrared photonic integration given their broadband infrared transparency and compatibility with silicon photonic integration. In this paper, we discuss our recent work exploring integrated chalcogenide glass based photonic devices for IR spectroscopic chemical analysis, including on-chip cavityenhanced chemical sensing and monolithic integration of mid-IR waveguides with photodetectors.

Recent Advance in Liquid Chromatography/Mass Spectrometry Techniques for Environmental Analysis in Japan

PubMed Central

Suzuki, Shigeru

2014-01-01

The techniques and measurement methods developed in the Environmental Survey and Monitoring of Chemicals by Japan’s Ministry of the Environment, as well as a large amount of knowledge archived in the survey, have led to the advancement of environmental analysis. Recently, technologies such as non-target liquid chromatography/high resolution mass spectrometry and liquid chromatography with micro bore column have further developed the field. Here, the general strategy of a method developed for the liquid chromatography/mass spectrometry (LC/MS) analysis of environmental chemicals with a brief description is presented. Also, a non-target analysis for the identification of environmental pollutants using a provisional fragment database and “MsMsFilter,” an elemental composition elucidation tool, is presented. This analytical method is shown to be highly effective in the identification of a model chemical, the pesticide Bendiocarb. Our improved micro-liquid chromatography injection system showed substantially enhanced sensitivity to perfluoroalkyl substances, with peak areas 32–71 times larger than those observed in conventional LC/MS. PMID:26819891

Component pattern analysis of chemicals using multispectral THz imaging system

NASA Astrophysics Data System (ADS)

Kawase, Kodo; Ogawa, Yuichi; Watanabe, Yuki

2004-04-01

We have developed a novel basic technology for terahertz (THz) imaging, which allows detection and identification of chemicals by introducing the component spatial pattern analysis. The spatial distributions of the chemicals were obtained from terahertz multispectral transillumination images, using absorption spectra previously measured with a widely tunable THz-wave parametric oscillator. Further we have applied this technique to the detection and identification of illicit drugs concealed in envelopes. The samples we used were methamphetamine and MDMA, two of the most widely consumed illegal drugs in Japan, and aspirin as a reference.

Chemical Stockpile Disposal Program. Risk Analysis of the Disposal of Chemical Munitions at Regional or National Sites.

DTIC Science & Technology

1987-08-01

THE DISPOSAL OF CNEM.. CU) GA TECHNOLOGIES INC SRN DIEGO CA A H SARSELL ET AL. RUG 97 GA-C- i @563 UNLRSS FIED S APEO-CDE-IS- 9 ?SIGDRAA±5-85-D-822...F/ 15/.3 NL I ihhhhhhhhhhhhlm I fflfflffllfllfllfllf smhhhhhhhhhhh ~1.02 U.,5 A I *Pig- FiLE copy CHEMICAL STOCKPILE DISPOSAL PROGRAM RISK ANALYSIS...vr~. ’ . - a ’ a’ ’- . ,I1 - .V [ N- VW; W UU V. , U .U : , r ,,, - . ..... . SECURITY CLASSIFICATION OF THIS PAGE IM : I omApproved

Space Shuttle solid rocket motor exposure monitoring

NASA Technical Reports Server (NTRS)

Brown, S. W.

1993-01-01

During the processing of the Space Shuttle Solid Rocket Booster (SRB), segments at the Kennedy Space Center, an odor was detected around the solid propellant. An Industrial Hygiene survey was conducted to determine the chemical identity of the SRB offgassing constituents. Air samples were collected inside a forward SRB segment and analyzed to determine chemical composition. Specific chemical analysis for suspected offgassing constituents of the propellant indicated ammonia to be present. A gas chromatograph mass spectroscopy (GC/MS) analysis of the air samples detected numerous high molecular weight hydrocarbons.

Identification or Development of Chemical Analysis Methods for Plants and Animal Tissues

DTIC Science & Technology

1981-01-01

Report No. DRXTH-TE-CR-80086 [E EMWSTEEACISITE - IDENTIFICATION OR DEVELOPMENT OF CHEMICAL ANALYSISI METHODS FOR PLANTS AND ANIMAL TISSUES D l...86i 4TITLE (ansdo"t) TYPE or" P 4. Iih~iti.)Final epwt. )9 A4,417 ~, Identlifiation or Development of Chemical I-g 9 O d 18 Analysis Methods for Plants...n TN oT sacmpihdo in. wEr DContinng er adetcsr aid Iuent bybopkmertda lo aeo 1.5th 1/s deeipta24ndectr Tritrotasolsoepae d andT Boloia Matrc,, 1473

A Continuation of Base-line Studies for Environmentally Monitoring Space Transportation Systems at John F. Kennedy Space Center. Volume 2; Chemical Studies of Rainfall and Soil Analysis

NASA Technical Reports Server (NTRS)

Madsen, B. C.

1980-01-01

The results of a study which was designed to monitor, characterize, and evaluate the chemical composition of precipitation (rain) which fell at the Kennedy Space Center, Florida (KSC) during the period July 1977 to March 1979 are reported. Results which were obtained from a soil sampling and associated chemical analysis are discussed. The purpose of these studies was to determine the environmental perturbations which might be caused by NASA space activities.

Chemical analysis of DC745 Materials: DEV Lot 1 reinvestigation; barcodes P053387, P053388, and P053389

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

Dirmyer, Matthew R.

This report serves as a follow up to our initial development lot 1 chemical analysis report (LA-UR-16-21970). The purpose of that report was to determine whether or not certain combinations of resin lots and curing agent lots resulted in chemical differences in the final material. One finding of that report suggested that pad P053389 was different from the three other pads analyzed. This report consists of chemical analysis of P053387, P053388, and a reinvestigation of P053389 all of which came from the potentially suspect combination of resin and curing agents lot. The goal of this report is to determine whethermore » the observations relating to P053389 were isolated to that particular pad or systemic to that combination of resin and curing agent lot. The following suite of analyses were performed on the pads: Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Fourier Transform Infrared Spectroscopy (FT-IR), and Solid State Nuclear Magnetic Resonance (NMR). The overall conclusions of the study are that pads P053387 and P053388 behave more consistently with the pads of other resin lot and curing agent lot combinations and that the chemical observations made regarding pad P053389 are isolated to that pad and not representative of an issue with that resin lot and curing agent lot combination.« less

Tile-Based Fisher Ratio Analysis of Comprehensive Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry (GC × GC – TOFMS) Data using a Null Distribution Approach

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

Parsons, Brendon A.; Marney, Luke C.; Siegler, William C.

Multi-dimensional chromatographic instrumentation produces information-rich, and chemically complex data containing meaningful chemical signals and/or chemical patterns. Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC – TOFMS) is a prominent instrumental platform that has been applied extensively for discovery-based experimentation, where samples are sufficiently volatile or amenable to derivatization. Use of GC × GC – TOFMS and associated data analysis strategies aim to uncover meaningful chemical signals or chemical patterns. However, for complex samples, meaningful chemical information is often buried in a background of less meaningful chemical signal and noise. In this report, we utilize the tile-based F-ratiomore » software in concert with the standard addition method by spiking non-native chemicals into a diesel fuel matrix at low concentrations. While the previous work studied the concentration range of 100-1000 ppm, the current study focuses on the 0 ppm to 100 ppm analyte spike range. This study demonstrates the sensitivity and selectivity of the tile-based F-ratio software for discovery of true positives in the non-targeted analysis of a chemically complex and analytically challenging sample matrix. By exploring the low concentration spike levels, we gain a better understanding of the limit of detection (LOD) of the tile-based F-ratio software with GC × GC – TOFMS data.« less

Some Sensitivity Studies of Chemical Transport Simulated in Models of the Soil-Plant-Litter System

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

Begovich, C.L.

2002-10-28

Fifteen parameters in a set of five coupled models describing carbon, water, and chemical dynamics in the soil-plant-litter system were varied in a sensitivity analysis of model response. Results are presented for chemical distribution in the components of soil, plants, and litter along with selected responses of biomass, internal chemical transport (xylem and phloem pathways), and chemical uptake. Response and sensitivity coefficients are presented for up to 102 model outputs in an appendix. Two soil properties (chemical distribution coefficient and chemical solubility) and three plant properties (leaf chemical permeability, cuticle thickness, and root chemical conductivity) had the greatest influence onmore » chemical transport in the soil-plant-litter system under the conditions examined. Pollutant gas uptake (SO{sub 2}) increased with change in plant properties that increased plant growth. Heavy metal dynamics in litter responded to plant properties (phloem resistance, respiration characteristics) which induced changes in the chemical cycling to the litter system. Some of the SO{sub 2} and heavy metal responses were not expected but became apparent through the modeling analysis.« less

ANALYSIS OF MACROINVERTEBRATE ASSEMBLAGES IN RELATION TO ENVIRONMENTAL GRADIENTS IN ROCKY MOUNTAIN STREAMS

EPA Science Inventory

Using redundancy analysis (RDA) and canonical correspondence analysis (CCA), we assessed relationships among chemical and physical characteristics and macroinvertebrate assemblages at stream sites sampled by the Regional Environmental Monitoring and Assessment Program (R-EMAP) in...

Chemical analysis of extracting transition metal oxides from polymetallic ore by sulphate process

NASA Astrophysics Data System (ADS)

Enkh-Uyanga, Otgon-Uul; Munkhtsetseg, Baatar; Urangoo, Urtnasan; Tserendulam, Enkhtur; Agiimaa, Davaadorj

2017-06-01

In this research work we attempt to improve the purity of polymetallic ores in Mongolia whilst developing practical applications of its refinement processes and this paper presents the results of chemical research of extracting transition metal titanium oxides, ferrous oxide and rare earth oxides from polymetallic ore. Thereby, chemical and mineral analysis of polymetallic ore is carried out basis of responses to the support process at various degrees of water whereas transition metal sulphates solubility differ. As a result of sulphate and resulphurization process we have extracted anatase with 62.5 percent titanium dioxide and brookite mineral with 89.6 percent of titanium dioxide as well as mineral with 83.8 percent of ferrous oxide hematite and rare earth oxides with 57.6 percent of cerium oxide. These oxides are identified under various conditions in the thermal processing. The morphology structure and chemical content compound of the mineral has been verified as a result of the XRF, XRD, SEM-EDX analysis.

DataWarrior: an open-source program for chemistry aware data visualization and analysis.

PubMed

Sander, Thomas; Freyss, Joel; von Korff, Modest; Rufener, Christian

2015-02-23

Drug discovery projects in the pharmaceutical industry accumulate thousands of chemical structures and ten-thousands of data points from a dozen or more biological and pharmacological assays. A sufficient interpretation of the data requires understanding, which molecular families are present, which structural motifs correlate with measured properties, and which tiny structural changes cause large property changes. Data visualization and analysis software with sufficient chemical intelligence to support chemists in this task is rare. In an attempt to contribute to filling the gap, we released our in-house developed chemistry aware data analysis program DataWarrior for free public use. This paper gives an overview of DataWarrior's functionality and architecture. Exemplarily, a new unsupervised, 2-dimensional scaling algorithm is presented, which employs vector-based or nonvector-based descriptors to visualize the chemical or pharmacophore space of even large data sets. DataWarrior uses this method to interactively explore chemical space, activity landscapes, and activity cliffs.

Chronological record of environmental chemicals from analysis of stratified vertebrate excretion deposited in a sheltered environment

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

Petit, M.G.; Altenbach, J.S.

1973-01-01

Guano deposits of the migratory free-tailed bat Tadarida brasiliensis are stratified into distinguishable annual layers in some caves in the American Southwest. These layers may be dated and analyzed for environmental chemicals thus providing a chronological record of selected chemicals in the food chain of this mammal. It is found that the annual Hg fluctuations observed in the guano correlate with annual production figures of a nearby copper smelter. Analysis of the terms in a mathematical model suggests that the major mechanism by which smelter mercury enters the bat's food chain is dry fallout. A 1-yr delay time between peaksmore » and dips in industrial output and peaks and dips in the mercury present in guano indicate that industrial mercury is ingested by the bat indirectly via the food chain. The preliminary data presented here indicate that analysis of old deposits (preindustrial revolution) will provide baseline data for environmental chemicals.« less

Computational singular perturbation analysis of stochastic chemical systems with stiffness

DOE PAGES

Wang, Lijin; Han, Xiaoying; Cao, Yanzhao; ...

2017-01-25

Computational singular perturbation (CSP) is a useful method for analysis, reduction, and time integration of stiff ordinary differential equation systems. It has found dominant utility, in particular, in chemical reaction systems with a large range of time scales at continuum and deterministic level. On the other hand, CSP is not directly applicable to chemical reaction systems at micro or meso-scale, where stochasticity plays an non-negligible role and thus has to be taken into account. In this work we develop a novel stochastic computational singular perturbation (SCSP) analysis and time integration framework, and associated algorithm, that can be used to notmore » only construct accurately and efficiently the numerical solutions to stiff stochastic chemical reaction systems, but also analyze the dynamics of the reduced stochastic reaction systems. Furthermore, the algorithm is illustrated by an application to a benchmark stochastic differential equation model, and numerical experiments are carried out to demonstrate the effectiveness of the construction.« less

Combination of multivariate curve resolution and multivariate classification techniques for comprehensive high-performance liquid chromatography-diode array absorbance detection fingerprints analysis of Salvia reuterana extracts.

PubMed

Hakimzadeh, Neda; Parastar, Hadi; Fattahi, Mohammad

2014-01-24

In this study, multivariate curve resolution (MCR) and multivariate classification methods are proposed to develop a new chemometric strategy for comprehensive analysis of high-performance liquid chromatography-diode array absorbance detection (HPLC-DAD) fingerprints of sixty Salvia reuterana samples from five different geographical regions. Different chromatographic problems occurred during HPLC-DAD analysis of S. reuterana samples, such as baseline/background contribution and noise, low signal-to-noise ratio (S/N), asymmetric peaks, elution time shifts, and peak overlap are handled using the proposed strategy. In this way, chromatographic fingerprints of sixty samples are properly segmented to ten common chromatographic regions using local rank analysis and then, the corresponding segments are column-wise augmented for subsequent MCR analysis. Extended multivariate curve resolution-alternating least squares (MCR-ALS) is used to obtain pure component profiles in each segment. In general, thirty-one chemical components were resolved using MCR-ALS in sixty S. reuterana samples and the lack of fit (LOF) values of MCR-ALS models were below 10.0% in all cases. Pure spectral profiles are considered for identification of chemical components by comparing their resolved spectra with the standard ones and twenty-four components out of thirty-one components were identified. Additionally, pure elution profiles are used to obtain relative concentrations of chemical components in different samples for multivariate classification analysis by principal component analysis (PCA) and k-nearest neighbors (kNN). Inspection of the PCA score plot (explaining 76.1% of variance accounted for three PCs) showed that S. reuterana samples belong to four clusters. The degree of class separation (DCS) which quantifies the distance separating clusters in relation to the scatter within each cluster is calculated for four clusters and it was in the range of 1.6-5.8. These results are then confirmed by kNN. In addition, according to the PCA loading plot and kNN dendrogram of thirty-one variables, five chemical constituents of luteolin-7-o-glucoside, salvianolic acid D, rosmarinic acid, lithospermic acid and trijuganone A are identified as the most important variables (i.e., chemical markers) for clusters discrimination. Finally, the effect of different chemical markers on samples differentiation is investigated using counter-propagation artificial neural network (CP-ANN) method. It is concluded that the proposed strategy can be successfully applied for comprehensive analysis of chromatographic fingerprints of complex natural samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Chemical Analysis of the Moon at the Surveyor VI Landing Site: Preliminary Results.

PubMed

Turkevich, A L; Patterson, J H; Franzgrote, E J

1968-06-07

The alpha-scattering experiment aboard soft-landing Surveyor VI has provided a chemical analysis of the surface of the moon in Sinus Medii. The preliminary results indicate that, within experimental errors, the composition is the same as that found by Surveyor V in Mare Tranquillitatis. This finding suggests that large portions of the lunar maria resemble basalt in composition.

CHEMICAL ANALYSIS OF REVERSE OSMOSIS MEMBRANE AND XAD RESIN ADSORPTION CONCENTRATES OF WATER DISINFECTED BY CHLORINATION OR OZONATION/CHLORINATION PROCESSES

EPA Science Inventory

Chemical Analysis of Reverse Osmosis Membrane and XAD Resin Adsorption Concentrates of Water Disinfected by Chlorination or Ozonation/Chlorination Processes.

J. E. Simmons1, S.D. Richardson2, K.M. Schenck3, T. F. Speth3, R. J. Miltner3 and A. D. Thruston2

1 NHEE...

Ontology-based systematic representation and analysis of traditional Chinese drugs against rheumatism.

PubMed

Liu, Qingping; Wang, Jiahao; Zhu, Yan; He, Yongqun

2017-12-21

Rheumatism represents any disease condition marked with inflammation and pain in the joints, muscles, or connective tissues. Many traditional Chinese drugs have been used for a long time to treat rheumatism. However, a comprehensive information source for these drugs is still missing, and their anti-rheumatism mechanisms remain unclear. An ontology for anti-rheumatism traditional Chinese drugs would strongly support the representation, analysis, and understanding of these drugs. In this study, we first systematically collected reported information about 26 traditional Chinese decoction pieces drugs, including their chemical ingredients and adverse events (AEs). By mostly reusing terms from existing ontologies (e.g., TCMDPO for traditional Chinese medicines, NCBITaxon for taxonomy, ChEBI for chemical elements, and OAE for adverse events) and making semantic axioms linking different entities, we developed the Ontology of Chinese Medicine for Rheumatism (OCMR) that includes over 3000 class terms. Our OCMR analysis found that these 26 traditional Chinese decoction pieces are made from anatomic entities (e.g., root and stem) from 3 Bilateria animals and 23 Mesangiospermae plants. Anti-inflammatory and antineoplastic roles are important for anti-rheumatism drugs. Using the total of 555 unique ChEBI chemical entities identified from these drugs, our ChEBI-based classification analysis identified 18 anti-inflammatory, 33 antineoplastic chemicals, and 9 chemicals (including 3 diterpenoids and 3 triterpenoids) having both anti-inflammatory and antineoplastic roles. Furthermore, our study detected 22 diterpenoids and 23 triterpenoids, including 16 pentacyclic triterpenoids that are likely bioactive against rheumatism. Six drugs were found to be associated with 184 unique AEs, including three AEs (i.e., dizziness, nausea and vomiting, and anorexia) each associated with 5 drugs. Several chemical entities are classified as neurotoxins (e.g., diethyl phthalate) and allergens (e.g., eugenol), which may explain the formation of some TCD AEs. The OCMR could be efficiently queried for useful information using SPARQL scripts. The OCMR ontology was developed to systematically represent 26 traditional anti-rheumatism Chinese drugs and their related information. The OCMR analysis identified possible anti-rheumatism and AE mechanisms of these drugs. Our novel ontology-based approach can also be applied to systematic representation and analysis of other traditional Chinese drugs.

Hydrogen fluoride (HF) substance flow analysis for safe and sustainable chemical industry.

PubMed

Kim, Junbeum; Hwang, Yongwoo; Yoo, Mijin; Chen, Sha; Lee, Ik-Mo

2017-11-01

In this study, the chemical substance flow of hydrogen fluoride (hydrofluoric acid, HF) in domestic chemical industries in 2014 was analyzed in order to provide a basic material and information for the establishment of organized management system to ensure safety during HF applications. A total of 44,751 tons of HF was made by four domestic companies (in 2014); import amount was 95,984 tons in 2014 while 21,579 tons of HF was imported in 2005. The export amount of HF was 2180 tons, of which 2074 ton (China, 1422 tons, U.S. 524 tons, and Malaysia, 128 tons) was exported for the manufacturing of semiconductors. Based on the export and import amounts, it can be inferred that HF was used for manufacturing semiconductors. The industries applications of 161,123 tons of HF were as follows: manufacturing of basic inorganic chemical substance (27,937 tons), manufacturing of other chemical products such as detergents (28,208 tons), manufacturing of flat display (24,896 tons), and manufacturing of glass container package (22,002 tons). In this study, an analysis of the chemical substance flow showed that HF was mainly used in the semiconductor industry as well as glass container manufacturing. Combined with other risk management tools and approaches in the chemical industry, the chemical substance flow analysis (CSFA) can be a useful tool and method for assessment and management. The current CSFA results provide useful information for policy making in the chemical industry and national systems. Graphical abstract Hydrogen fluoride chemical substance flows in 2014 in South Korea.

Frontiers in Chemistry.

ERIC Educational Resources Information Center

Joyce, Robert M., Ed.

1980-01-01

This article describes recent progress in chemical synthesis which depends on comparable advances in other areas of chemistry. Analysis and theories of chemical structure and reactions are determinants in progress in chemical synthesis and are described also. (Author/SA)

Analysis of chemical concepts as the basic of virtual laboratory development and process science skills in solubility and solubility product subject

NASA Astrophysics Data System (ADS)

Syafrina, R.; Rohman, I.; Yuliani, G.

2018-05-01

This study aims to analyze the concept characteristics of solubility and solubility products that will serve as the basis for the development of virtual laboratory and students' science process skills. Characteristics of the analyzed concepts include concept definitions, concept attributes, and types of concepts. The concept analysis method uses concept analysis according to Herron. The results of the concept analysis show that there are twelve chemical concepts that become the prerequisite concept before studying the solubility and solubility and five core concepts that students must understand in the solubility and Solubility product. As many as 58.3% of the definitions of the concepts contained in high school textbooks support students' science process skills, the rest of the definition of the concept is memorized. Concept attributes that meet three levels of chemical representation and can be poured into a virtual laboratory have a percentage of 66.6%. Type of concept, 83.3% is a concept based on principle; and 16.6% concepts that state the process. Meanwhile, the science process skills that can be developed based on concept analysis are the ability to observe, calculate, measure, predict, interpret, hypothesize, apply, classify, and inference.

Molecular structure, vibrational analysis (IR and Raman) and quantum chemical investigations of 1-aminoisoquinoline

NASA Astrophysics Data System (ADS)

Sivaprakash, S.; Prakash, S.; Mohan, S.; Jose, Sujin P.

2017-12-01

Quantum chemical calculations of energy and geometrical parameters of 1-aminoisoquinoline [1-AIQ] were carried out by using DFT/B3LYP method using 6-311G (d,p), 6-311G++(d,p) and cc-pVTZ basis sets. The vibrational wavenumbers were computed for the energetically most stable, optimized geometry. The vibrational assignments were performed on the basis of potential energy distribution (PED) using VEDA program. The NBO analysis was done to investigate the intra molecular charge transfer of the molecule. The frontier molecular orbital (FMO) analysis was carried out and the chemical reactivity descriptors of the molecule were studied. The Mulliken charge analysis, molecular electrostatic potential (MEP), HOMO-LUMO energy gap and the related properties were also investigated at B3LYP level. The absorption spectrum of the molecule was studied from UV-Visible analysis by using time-dependent density functional theory (TD-DFT). Fourier Transform Infrared spectrum (FT-IR) and Raman spectrum of 1-AIQ compound were analyzed and recorded in the range 4000-400 cm-1 and 3500-100 cm-1 respectively. The experimentally determined wavenumbers were compared with those calculated theoretically and they complement each other.

Advanced multivariate analysis to assess remediation of hydrocarbons in soils.

PubMed

Lin, Deborah S; Taylor, Peter; Tibbett, Mark

2014-10-01

Accurate monitoring of degradation levels in soils is essential in order to understand and achieve complete degradation of petroleum hydrocarbons in contaminated soils. We aimed to develop the use of multivariate methods for the monitoring of biodegradation of diesel in soils and to determine if diesel contaminated soils could be remediated to a chemical composition similar to that of an uncontaminated soil. An incubation experiment was set up with three contrasting soil types. Each soil was exposed to diesel at varying stages of degradation and then analysed for key hydrocarbons throughout 161 days of incubation. Hydrocarbon distributions were analysed by Principal Coordinate Analysis and similar samples grouped by cluster analysis. Variation and differences between samples were determined using permutational multivariate analysis of variance. It was found that all soils followed trajectories approaching the chemical composition of the unpolluted soil. Some contaminated soils were no longer significantly different to that of uncontaminated soil after 161 days of incubation. The use of cluster analysis allows the assignment of a percentage chemical similarity of a diesel contaminated soil to an uncontaminated soil sample. This will aid in the monitoring of hydrocarbon contaminated sites and the establishment of potential endpoints for successful remediation.

A Comparison of Tissue Spray and Lipid Extract Direct Injection Electrospray Ionization Mass Spectrometry for the Differentiation of Eutopic and Ectopic Endometrial Tissues

NASA Astrophysics Data System (ADS)

Chagovets, Vitaliy; Wang, Zhihao; Kononikhin, Alexey; Starodubtseva, Natalia; Borisova, Anna; Salimova, Dinara; Popov, Igor; Kozachenko, Andrey; Chingin, Konstantin; Chen, Huanwen; Frankevich, Vladimir; Adamyan, Leila; Sukhikh, Gennady

2018-02-01

Recent research revealed that tissue spray mass spectrometry enables rapid molecular profiling of biological tissues, which is of great importance for the search of disease biomarkers as well as for online surgery control. However, the payback for the high speed of analysis in tissue spray analysis is the generally lower chemical sensitivity compared with the traditional approach based on the offline chemical extraction and electrospray ionization mass spectrometry detection. In this study, high resolution mass spectrometry analysis of endometrium tissues of different localizations obtained using direct tissue spray mass spectrometry in positive ion mode is compared with the results of electrospray ionization analysis of lipid extracts. Identified features in both cases belong to three lipid classes: phosphatidylcholines, phosphoethanolamines, and sphingomyelins. Lipids coverage is validated by hydrophilic interaction liquid chromatography with mass spectrometry of lipid extracts. Multivariate analysis of data from both methods reveals satisfactory differentiation of eutopic and ectopic endometrium tissues. Overall, our results indicate that the chemical information provided by tissue spray ionization is sufficient to allow differentiation of endometrial tissues by localization with similar reliability but higher speed than in the traditional approach relying on offline extraction.

Discrimination of the rare medicinal plant Dendrobium officinale based on naringenin, bibenzyl, and polysaccharides.

PubMed

Chen, Xiaomei; Wang, Fangfei; Wang, Yunqiang; Li, Xuelan; Wang, Airong; Wang, Chunlan; Guo, Shunxing

2012-12-01

The aim of this study was to establish a method for discriminating Dendrobium officinale from four of its close relatives Dendrobium chrysanthum, Dendrobium crystallinum, Dendrobium aphyllum and Dendrobium devonianum based on chemical composition analysis. We analyzed 62 samples of 24 Dendrobium species. High performance liquid chromatography analysis confirmed that the four low molecular weight compounds 4',5,7-trihydroxyflavanone (naringenin), 3,4-dihydroxy-4',5-dime-thoxybibenzyl (DDB-2), 3',4-dihydroxy-3,5'-dimethoxybibenzyl (gigantol), and 4,4'-dihydroxy-3,3',5-trimethoxybibenzy (moscatilin), were common in the genus. The phenol-sulfuric acid method was used to quantify polysaccharides, and the monosaccharide composition of the polysaccharides was determined by gas chromatography. Stepwise discriminant analysis was used to differentiate among the five closely related species based on the chemical composition analysis. This proved to be a simple and accurate approach for discriminating among these species. The results also showed that the polysaccharide content, the amounts of the four low molecular weight compounds, and the mannose to glucose ratio, were important factors for species discriminant. Therefore, we propose that a chemical analysis based on quantification of naringenin, bibenzyl, and polysaccharides is effective for identifying D. officinale.

Meta-Analysis of the Chemical and Non-Chemical Stressors Affecting Childhood Obesity

EPA Science Inventory

Worldwide, approximately 42 million children under the age of 5 years are considered overweight or obese. While much research has focused on individual behaviors impacting obesity, little research has emphasized the complex interactions of numerous chemical and non-chemical stres...

PINS Spectrum Identification Guide

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

A.J. Caffrey

2012-03-01

The Portable Isotopic Neutron Spectroscopy—PINS, for short—system identifies the chemicals inside munitions and containers without opening them, a decided safety advantage if the fill chemical is a hazardous substance like a chemical warfare agent or an explosive. The PINS Spectrum Identification Guide is intended as a reference for technical professionals responsible for the interpretation of PINS gamma-ray spectra. The guide is divided into two parts. The three chapters that constitute Part I cover the science and technology of PINS. Neutron activation analysis is the focus of Chapter 1. Chapter 2 explores PINS hardware, software, and related operational issues. Gamma-ray spectralmore » analysis basics are introduced in Chapter 3. The six chapters of Part II cover the identification of PINS spectra in detail. Like the PINS decision tree logic, these chapters are organized by chemical element: phosphorus-based chemicals, chlorine-based chemicals, etc. These descriptions of hazardous, toxic, and/or explosive chemicals conclude with a chapter on the identification of the inert chemicals, e.g. sand, used to fill practice munitions.« less

Microstructural characterization of multiphase chocolate using X-ray microtomography.

PubMed

Frisullo, Pierangelo; Licciardello, Fabio; Muratore, Giuseppe; Del Nobile, Matteo Alessandro

2010-09-01

In this study, X-ray microtomography (μCT) was used for the image analysis of the microstructure of 12 types of Italian aerated chocolate chosen to exhibit variability in terms of cocoa mass content. Appropriate quantitative 3-dimensional parameters describing the microstructure were calculated, for example, the structure thickness (ST), object structure volume ratio (OSVR), and the percentage object volume (POV). Chemical analysis was also performed to correlate the microstructural data to the chemical composition of the samples. Correlation between the μCT parameters acquired for the pore microstructure evaluation and the chemical analysis revealed that the sugar crystals content does not influence the pore structure and content. On the other hand, it revealed that there is a strong correlation between the POV and the sugar content obtained by chemical analysis. The results from this study show that μCT is a suitable technique for the microstructural analysis of confectionary products such as chocolates and not only does it provide an accurate analysis of the pores and microstructure but the data obtained could also be used to aid in the assessment of its composition and consistency with label specifications. X-ray microtomography (μCT) is a noninvasive and nondestructive 3-D imaging technique that has several advantages over other methods, including the ability to image low-moisture materials. Given the enormous success of μCT in medical applications, material science, chemical engineering, geology, and biology, it is not surprising that in recent years much attention has been focused on extending this imaging technique to food science as a useful technique to aid in the study of food microstructure. X-ray microtomography provides in-depth information on the microstructure of the food product being tested; therefore, a better understanding of the physical structure of the product and from an engineering perspective, knowledge about the microstructure of foods can be used to identify the important processing parameters that affect the quality of a product.

Two-dimensional and three-dimensional dynamic imaging of live biofilms in a microchannel by time-of-flight secondary ion mass spectrometry

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

Hua, Xin; Marshall, Matthew J.; Xiong, Yijia

2015-05-01

A vacuum compatible microfluidic reactor, SALVI (System for Analysis at the Liquid Vacuum Interface) was employed for in situ chemical imaging of live biofilms using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Depth profiling by sputtering materials in sequential layers resulted in live biofilm spatial chemical mapping. 2D images were reconstructed to report the first 3D images of hydrated biofilm elucidating spatial and chemical heterogeneity. 2D image principal component analysis (PCA) was conducted among biofilms at different locations in the microchannel. Our approach directly visualized spatial and chemical heterogeneity within the living biofilm by dynamic liquid ToF-SIMS.

Forensic and homeland security applications of modern portable Raman spectroscopy.

PubMed

Izake, Emad L

2010-10-10

Modern detection and identification of chemical and biological hazards within the forensic and homeland security contexts may well require conducting the analysis in field while adapting a non-contact approach to the hazard. Technological achievements on both surface and resonance enhancement Raman scattering re-developed Raman spectroscopy to become the most adaptable spectroscopy technique for stand-off and non-contact analysis of hazards. On the other hand, spatially offset Raman spectroscopy proved to be very valuable for non-invasive chemical analysis of hazards concealed within non-transparent containers and packaging. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Composition dependent effects in gas chromatography. [used in chemical analysis system onboard unmanned roving vehicle on Mars

NASA Technical Reports Server (NTRS)

Lavoie, R. C.

1974-01-01

Fundamantal concepts are developed which are required to optimize a gas chromatograph-mass spectrometer chemical analysis system suitable for use on an unmanned roving vehicle for Mars exploration. Prior efforts have developed simulation models for the chromatograph which were compared with data obtained from a test facility. Representation of binary systems by superposition was shown to be a first-order approximation and in certain cases large discrepencies were noted. This subtask has as its objective generation of additional binary data and analysis of the observed nonlinear effects.

State of the art in on-line techniques coupled to flow injection analysis FIA/on-line- a critical review

PubMed Central

Puchades, R.; Maquieira, A.; Atienza, J.; Herrero, M. A.

1990-01-01

Flow injection analysis (FIA) has emerged as an increasingly used laboratory tool in chemical analysis. Employment of the technique for on-line sample treatment and on-line measurement in chemical process control is a growing trend. This article reviews the recent applications of FlA. Most papers refer to on-line sample treatment. Although FIA is very well suited to continuous on-line process monitoring, few examples have been found in this areamost of them have been applied to water treatment or fermentation processes. PMID:18925271

Electrochemical Sensors for Clinic Analysis

PubMed Central

Wang, You; Xu, Hui; Zhang, Jianming; Li, Guang

2008-01-01

Demanded by modern medical diagnosis, advances in microfabrication technology have led to the development of fast, sensitive and selective electrochemical sensors for clinic analysis. This review addresses the principles behind electrochemical sensor design and fabrication, and introduces recent progress in the application of electrochemical sensors to analysis of clinical chemicals such as blood gases, electrolytes, metabolites, DNA and antibodies, including basic and applied research. Miniaturized commercial electrochemical biosensors will form the basis of inexpensive and easy to use devices for acquiring chemical information to bring sophisticated analytical capabilities to the non-specialist and general public alike in the future. PMID:27879810

Plant seed species identification from chemical fingerprints: a high-throughput application of direct analysis in real time mass spectrometry.

PubMed

Lesiak, Ashton D; Cody, Robert B; Dane, A John; Musah, Rabi A

2015-09-01

Plant species identification based on the morphological features of plant parts is a well-established science in botany. However, species identification from seeds has largely been unexplored, despite the fact that the seeds contain all of the genetic information that distinguishes one plant from another. Using seeds of genus Datura plants, we show here that the mass spectrum-derived chemical fingerprints for seeds of the same species are similar. On the other hand, seeds from different species within the same genus display distinct chemical signatures, even though they may contain similar characteristic biomarkers. The intraspecies chemical signature similarities on the one hand, and interspecies fingerprint differences on the other, can be processed by multivariate statistical analysis methods to enable rapid species-level identification and differentiation. The chemical fingerprints can be acquired rapidly and in a high-throughput manner by direct analysis in real time mass spectrometry (DART-MS) analysis of the seeds in their native form, without use of a solvent extract. Importantly, knowledge of the identity of the detected molecules is not required for species level identification. However, confirmation of the presence within the seeds of various characteristic tropane and other alkaloids, including atropine, scopolamine, scopoline, tropine, tropinone, and tyramine, was accomplished by comparison of the in-source collision-induced dissociation (CID) fragmentation patterns of authentic standards, to the fragmentation patterns observed in the seeds when analyzed under similar in-source CID conditions. The advantages, applications, and implications of the chemometric processing of DART-MS derived seed chemical signatures for species level identification and differentiation are discussed.

LSENS, a general chemical kinetics and sensitivity analysis code for homogeneous gas-phase reactions. 2: Code description and usage

NASA Technical Reports Server (NTRS)

Radhakrishnan, Krishnan; Bittker, David A.

1994-01-01

LSENS, the Lewis General Chemical Kinetics Analysis Code, has been developed for solving complex, homogeneous, gas-phase chemical kinetics problems and contains sensitivity analysis for a variety of problems, including nonisothermal situations. This report is part 2 of a series of three reference publications that describe LSENS, provide a detailed guide to its usage, and present many example problems. Part 2 describes the code, how to modify it, and its usage, including preparation of the problem data file required to execute LSENS. Code usage is illustrated by several example problems, which further explain preparation of the problem data file and show how to obtain desired accuracy in the computed results. LSENS is a flexible, convenient, accurate, and efficient solver for chemical reaction problems such as static system; steady, one-dimensional, inviscid flow; reaction behind incident shock wave, including boundary layer correction; and perfectly stirred (highly backmixed) reactor. In addition, the chemical equilibrium state can be computed for the following assigned states: temperature and pressure, enthalpy and pressure, temperature and volume, and internal energy and volume. For static problems the code computes the sensitivity coefficients of the dependent variables and their temporal derivatives with respect to the initial values of the dependent variables and/or the three rate coefficient parameters of the chemical reactions. Part 1 (NASA RP-1328) derives the governing equations describes the numerical solution procedures for the types of problems that can be solved by lSENS. Part 3 (NASA RP-1330) explains the kinetics and kinetics-plus-sensitivity-analysis problems supplied with LSENS and presents sample results.

Study of Intelligent Secure Chemical Inventory Management System

NASA Astrophysics Data System (ADS)

Shukran, Mohd Afizi Mohd; Naim Abdullah, Muhammad; Nazri Ismail, Mohd; Maskat, Kamaruzaman; Isa, Mohd Rizal Mohd; Shahfee Ishak, Muhammad; Adib Khairuddin, Muhamad

2017-08-01

Chemical inventory management system has been experiencing a new revolution from traditional inventory system which is manual to an automated inventory management system. In this paper, some review of the classic and modern approaches to chemical inventory management system has been discussed. This paper also describe about both type of inventory management. After a comparative analysis of the traditional method and automated method, it can be said that both methods have some distinctive characteristics. Moreover, the automated inventory management method has higher accuracy of calculation because the calculations are handled by software, eliminating possible errors and saving time. The automated inventory system also allows users and administrators to track the availability, location and consumption of chemicals. The study of this paper can provide forceful review analysis support for the chemical inventory management related research.

Proposal of an in silico profiler for categorisation of repeat dose toxicity data of hair dyes.

PubMed

Nelms, M D; Ates, G; Madden, J C; Vinken, M; Cronin, M T D; Rogiers, V; Enoch, S J

2015-05-01

This study outlines the analysis of 94 chemicals with repeat dose toxicity data taken from Scientific Committee on Consumer Safety opinions for commonly used hair dyes in the European Union. Structural similarity was applied to group these chemicals into categories. Subsequent mechanistic analysis suggested that toxicity to mitochondria is potentially a key driver of repeat dose toxicity for chemicals within each of the categories. The mechanistic hypothesis allowed for an in silico profiler consisting of four mechanism-based structural alerts to be proposed. These structural alerts related to a number of important chemical classes such as quinones, anthraquinones, substituted nitrobenzenes and aromatic azos. This in silico profiler is intended for grouping chemicals into mechanism-based categories within the adverse outcome pathway paradigm.

Broadband external cavity quantum cascade laser based sensor for gasoline detection

NASA Astrophysics Data System (ADS)

Ding, Junya; He, Tianbo; Zhou, Sheng; Li, Jinsong

2018-02-01

A new type of tunable diode spectroscopy sensor based on an external cavity quantum cascade laser (ECQCL) and a quartz crystal tuning fork (QCTF) were used for quantitative analysis of volatile organic compounds. In this work, the sensor system had been tested on different gasoline sample analysis. For signal processing, the self-established interpolation algorithm and multiple linear regression algorithm model were used for quantitative analysis of major volatile organic compounds in gasoline samples. The results were very consistent with that of the standard spectra taken from the Pacific Northwest National Laboratory (PNNL) database. In future, The ECQCL sensor will be used for trace explosive, chemical warfare agent, and toxic industrial chemical detection and spectroscopic analysis, etc.

Development of an automated on-line pepsin digestion-liquid chromatography-tandem mass spectrometry configuration for the rapid analysis of protein adducts of chemical warfare agents.

PubMed

Carol-Visser, Jeroen; van der Schans, Marcel; Fidder, Alex; Hulst, Albert G; van Baar, Ben L M; Irth, Hubertus; Noort, Daan

2008-07-01

Rapid monitoring and retrospective verification are key issues in protection against and non-proliferation of chemical warfare agents (CWA). Such monitoring and verification are adequately accomplished by the analysis of persistent protein adducts of these agents. Liquid chromatography-mass spectrometry (LC-MS) is the tool of choice in the analysis of such protein adducts, but the overall experimental procedure is quite elaborate. Therefore, an automated on-line pepsin digestion-LC-MS configuration has been developed for the rapid determination of CWA protein adducts. The utility of this configuration is demonstrated by the analysis of specific adducts of sarin and sulfur mustard to human butyryl cholinesterase and human serum albumin, respectively.

Statistical tables and charts showing geochemical variation in the Mesoproterozoic Big Creek, Apple Creek, and Gunsight formations, Lemhi group, Salmon River Mountains and Lemhi Range, central Idaho

USGS Publications Warehouse

Lindsey, David A.; Tysdal, Russell G.; Taggart, Joseph E.

2002-01-01

The principal purpose of this report is to provide a reference archive for results of a statistical analysis of geochemical data for metasedimentary rocks of Mesoproterozoic age of the Salmon River Mountains and Lemhi Range, central Idaho. Descriptions of geochemical data sets, statistical methods, rationale for interpretations, and references to the literature are provided. Three methods of analysis are used: R-mode factor analysis of major oxide and trace element data for identifying petrochemical processes, analysis of variance for effects of rock type and stratigraphic position on chemical composition, and major-oxide ratio plots for comparison with the chemical composition of common clastic sedimentary rocks.

Hydrazine reagents as derivatizing agents in environmental analysis--a critical review.

PubMed

Vogel, M; Büldt, A; Karst, U

2000-04-01

Hydrazine reagents are a well-known group of derivatizing agents for the determination of aldehydes and ketones in liquid and gaseous samples. Within this article, the most important hydrazine reagents are critically summarized, and their major applications in different fields, including environmental analysis, food chemistry and industrial analysis are introduced. As 2,4-dinitrophenylhydrazine (DNPH) is the basic reagent for several international standard procedures, its properties are discussed in detail. Particular focus is directed on the chemistry of the hydrazine reagents, and chemical interferences are considered. Recent methods for the determination of various oxidants using hydrazine reagents are presented as well. Due to limited space, this review does not cover the related field of carbohydrate analysis, although many chemical aspects are similar.

A Short History of Three Chemical Shifts

ERIC Educational Resources Information Center

Nagaoka, Shin-ichi

2007-01-01

A short history of chemical shifts in nuclear magnetic resonance (NMR), electron spectroscopy for chemical analysis (ESCA) and Mossbauer spectroscopy, which are useful for chemical studies, is described. The term chemical shift is shown to have originated in the mistaken assumption that nuclei of a given element would all undergo resonance at the…

Controlling organic chemical hazards in food manufacturing: a hazard analysis critical control points (HACCP) approach.

PubMed

Ropkins, K; Beck, A J

2002-08-01

Hazard analysis by critical control points (HACCP) is a systematic approach to the identification, assessment and control of hazards. Effective HACCP requires the consideration of all hazards, i.e., chemical, microbiological and physical. However, to-date most 'in-place' HACCP procedures have tended to focus on the control of microbiological and physical food hazards. In general, the chemical component of HACCP procedures is either ignored or limited to applied chemicals, e.g., food additives and pesticides. In this paper we discuss the application of HACCP to a broader range of chemical hazards, using organic chemical contaminants as examples, and the problems that are likely to arise in the food manufacturing sector. Chemical HACCP procedures are likely to result in many of the advantages previously identified for microbiological HACCP procedures: more effective, efficient and economical than conventional end-point-testing methods. However, the high costs of analytical monitoring of chemical contaminants and a limited understanding of formulation and process optimisation as means of controlling chemical contamination of foods are likely to prevent chemical HACCP becoming as effective as microbiological HACCP.

Mary J. Biddy | NREL

Science.gov Websites

| 303-384-7904 Research Interests The economic, social, and sustainability effects of the emerging technologies and platforms Process design and economic analysis Production of premium fuels and chemicals from Programs Strategic and Market Analysis (PI) Economic and Sustainability Analysis (contributor) Biological

USEPA EXAMPLE EXIT LEVEL ANALYSIS RESULTS

EPA Science Inventory

Developed by NERL/ERD for the Office of Solid Waste, the enclosed product provides an example uncertainty analysis (UA) and initial process-based sensitivity analysis (SA) of hazardous waste "exit" concentrations for 7 chemicals and metals using the 3MRA Version 1.0 Modeling Syst...

40 CFR 68.22 - Offsite consequence analysis parameters.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Offsite consequence analysis... PROGRAMS (CONTINUED) CHEMICAL ACCIDENT PREVENTION PROVISIONS Hazard Assessment § 68.22 Offsite consequence analysis parameters. (a) Endpoints. For analyses of offsite consequences, the following endpoints shall be...

Fourier Transform Infrared (FT-IR) and Laser Ablation Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) Imaging of Cerebral Ischemia: Combined Analysis of Rat Brain Thin Cuts Toward Improved Tissue Classification.

PubMed

Balbekova, Anna; Lohninger, Hans; van Tilborg, Geralda A F; Dijkhuizen, Rick M; Bonta, Maximilian; Limbeck, Andreas; Lendl, Bernhard; Al-Saad, Khalid A; Ali, Mohamed; Celikic, Minja; Ofner, Johannes

2018-02-01

Microspectroscopic techniques are widely used to complement histological studies. Due to recent developments in the field of chemical imaging, combined chemical analysis has become attractive. This technique facilitates a deepened analysis compared to single techniques or side-by-side analysis. In this study, rat brains harvested one week after induction of photothrombotic stroke were investigated. Adjacent thin cuts from rats' brains were imaged using Fourier transform infrared (FT-IR) microspectroscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The LA-ICP-MS data were normalized using an internal standard (a thin gold layer). The acquired hyperspectral data cubes were fused and subjected to multivariate analysis. Brain regions affected by stroke as well as unaffected gray and white matter were identified and classified using a model based on either partial least squares discriminant analysis (PLS-DA) or random decision forest (RDF) algorithms. The RDF algorithm demonstrated the best results for classification. Improved classification was observed in the case of fused data in comparison to individual data sets (either FT-IR or LA-ICP-MS). Variable importance analysis demonstrated that both molecular and elemental content contribute to the improved RDF classification. Univariate spectral analysis identified biochemical properties of the assigned tissue types. Classification of multisensor hyperspectral data sets using an RDF algorithm allows access to a novel and in-depth understanding of biochemical processes and solid chemical allocation of different brain regions.

An Inverse Analysis Approach to the Characterization of Chemical Transport in Paints

PubMed Central

Willis, Matthew P.; Stevenson, Shawn M.; Pearl, Thomas P.; Mantooth, Brent A.

2014-01-01

The ability to directly characterize chemical transport and interactions that occur within a material (i.e., subsurface dynamics) is a vital component in understanding contaminant mass transport and the ability to decontaminate materials. If a material is contaminated, over time, the transport of highly toxic chemicals (such as chemical warfare agent species) out of the material can result in vapor exposure or transfer to the skin, which can result in percutaneous exposure to personnel who interact with the material. Due to the high toxicity of chemical warfare agents, the release of trace chemical quantities is of significant concern. Mapping subsurface concentration distribution and transport characteristics of absorbed agents enables exposure hazards to be assessed in untested conditions. Furthermore, these tools can be used to characterize subsurface reaction dynamics to ultimately design improved decontaminants or decontamination procedures. To achieve this goal, an inverse analysis mass transport modeling approach was developed that utilizes time-resolved mass spectroscopy measurements of vapor emission from contaminated paint coatings as the input parameter for calculation of subsurface concentration profiles. Details are provided on sample preparation, including contaminant and material handling, the application of mass spectrometry for the measurement of emitted contaminant vapor, and the implementation of inverse analysis using a physics-based diffusion model to determine transport properties of live chemical warfare agents including distilled mustard (HD) and the nerve agent VX. PMID:25226346

Spatio-temporal variability of hydro-chemical characteristics of coastal waters of Gulf of Mannar Marine Biosphere Reserve (GoMMBR), South India

NASA Astrophysics Data System (ADS)

Kathiravan, K.; Natesan, Usha; Vishnunath, R.

2017-03-01

The intention of this study was to appraise the spatial and temporal variations in the physico-chemical parameters of coastal waters of Rameswaram Island, Gulf of Mannar Marine Biosphere Reserve, south India, using multivariate statistical techniques, such as cluster analysis, factor analysis and principal component analysis. Spatio-temporal variations among the physico-chemical parameters are observed in the coastal waters of Gulf of Mannar, especially during northeast and post monsoon seasons. It is inferred that the high loadings of pH, temperature, suspended particulate matter, salinity, dissolved oxygen, biochemical oxygen demand, chlorophyll a, nutrient species of nitrogen and phosphorus strongly determine the discrimination of coastal water quality. Results highlight the important role of monsoonal variations to determine the coastal water quality around Rameswaram Island.

[Revisiting the chemical diversity in prostatic calculi: a SEM and FT-IR investigation].

PubMed

Dessombz, A; Méria, P; Bazin, D; Foy, E; Rouzière, S; Weil, R; Daudon, M

2011-12-01

Revisiting the chemical diversity of the crystalline phases of prostatic calculi by means of SEM and FT-IR analysis. A set of 32 prostatic calculi has been studied by FT-IR and SEM. FT-IR analysis has determined the chemical composition of each prostatic calculus and the SEM observation has described the morphology of the calculi surfaces and layers. Infrared analysis revealed that 90.7% of the stones were mainly composed of calcium phosphates. However, several mineral phases previously not reported in prostatic calculi were observed, as brushite or octocalcium phosphate pentahydrate. Prostatic calculi exhibited a diversity of crystalline composition and morphology. As previously reported for urinary calculi, relationships between composition and morphology of prostatic stones and étiopathogenic conditions could be of interest in clinical practice. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Sequential-Injection Analysis: Principles, Instrument Construction, and Demonstration by a Simple Experiment

ERIC Educational Resources Information Center

Economou, A.; Tzanavaras, P. D.; Themelis, D. G.

2005-01-01

The sequential-injection analysis (SIA) is an approach to sample handling that enables the automation of manual wet-chemistry procedures in a rapid, precise and efficient manner. The experiments using SIA fits well in the course of Instrumental Chemical Analysis and especially in the section of Automatic Methods of analysis provided by chemistry…

Biogeographical Analysis of Chemical Co-Occurrence Data to Identify Priorities for Mixtures Research

EPA Science Inventory

A challenge with multiple chemical risk assessment is the need to consider the joint behavior of chemicals in mixtures. To address this need, pharmacologists and toxicologists have developed methods over the years to evaluate and test chemical interaction. In practice, however, t...

Physical-chemical property based sequence motifs and methods regarding same

DOEpatents

Braun, Werner [Friendswood, TX; Mathura, Venkatarajan S [Sarasota, FL; Schein, Catherine H [Friendswood, TX

2008-09-09

A data analysis system, program, and/or method, e.g., a data mining/data exploration method, using physical-chemical property motifs. For example, a sequence database may be searched for identifying segments thereof having physical-chemical properties similar to the physical-chemical property motifs.

EVALUATING AND DESIGNING CHEMICAL PROCESSES FOR ENVIRONMENTAL SUSTAINABILITY

EPA Science Inventory

Chemicals and chemical processes are at the heart of most environmental problems. This isn't surprising since chemicals make up all of the products we use in our lives. The common use of cjhemicals makes them of high interest for systems analysis, particularly because of environ...

LSENS: A General Chemical Kinetics and Sensitivity Analysis Code for homogeneous gas-phase reactions. Part 1: Theory and numerical solution procedures

NASA Technical Reports Server (NTRS)

Radhakrishnan, Krishnan

1994-01-01

LSENS, the Lewis General Chemical Kinetics and Sensitivity Analysis Code, has been developed for solving complex, homogeneous, gas-phase chemical kinetics problems and contains sensitivity analysis for a variety of problems, including nonisothermal situations. This report is part 1 of a series of three reference publications that describe LENS, provide a detailed guide to its usage, and present many example problems. Part 1 derives the governing equations and describes the numerical solution procedures for the types of problems that can be solved. The accuracy and efficiency of LSENS are examined by means of various test problems, and comparisons with other methods and codes are presented. LSENS is a flexible, convenient, accurate, and efficient solver for chemical reaction problems such as static system; steady, one-dimensional, inviscid flow; reaction behind incident shock wave, including boundary layer correction; and perfectly stirred (highly backmixed) reactor. In addition, the chemical equilibrium state can be computed for the following assigned states: temperature and pressure, enthalpy and pressure, temperature and volume, and internal energy and volume. For static problems the code computes the sensitivity coefficients of the dependent variables and their temporal derivatives with respect to the initial values of the dependent variables and/or the three rate coefficient parameters of the chemical reactions.

Biomarker discovery and transcriptomic responses in Daphnia magna exposed to munitions constituents.

PubMed

Garcia-Reyero, Natalia; Poynton, Helen C; Kennedy, Alan J; Guan, Xin; Escalon, B Lynn; Chang, Bonnie; Varshavsky, Julia; Loguinov, Alex V; Vulpe, Chris D; Perkins, Edward J

2009-06-01

Ecotoxicogenomic approaches are emerging as alternative methods in environmental monitoring because they allow insight into pollutant modes of action and help assess the causal agents and potential toxicity beyond the traditional end points of death, growth, and reproduction. Gene expression analysis has shown particular promise for identifying gene expression biomarkers of chemical exposure that can be further used to monitor specific chemical exposures in the environment. We focused on the development of gene expression markers to detect and discriminate between chemical exposures. Using a custom cDNA microarray for Daphnia magna, we identified distinct expression fingerprints in response to exposure at sublethal concentrations of Cu, Zn, Pb, and munitions constituents. Using the results obtained from microarray analysis, we chose a suite of potential biomarkers for each of the specific exposures. The selected potential biomarkers were tested in independent chemical exposures for specificity using quantitative reverse transcription polymerase chain reaction. Six genes were confirmed as differentially regulated bythe selected chemical exposures. Furthermore, each exposure was identified by response of a unique combination (suite) of individual gene expression biomarkers. These results demonstrate the potential for discovery and validation of novel biomarkers of chemical exposures using gene expression analysis, which could have broad applicability in environmental monitoring.

Chemical Industry Analysis Brief

EIA Publications

2005-01-01

The chemical industries are a cornerstone of the U.S. economy, converting raw materials such as oil, natural gas, air, water, metals, and minerals into thousands of various products. Chemicals are key materials for producing an extensive assortment of consumer goods.

Chemical discrimination of lubricant marketing types using direct analysis in real time time-of-flight mass spectrometry.

PubMed

Maric, Mark; Harvey, Lauren; Tomcsak, Maren; Solano, Angelique; Bridge, Candice

2017-06-30

In comparison to other violent crimes, sexual assaults suffer from very low prosecution and conviction rates especially in the absence of DNA evidence. As a result, the forensic community needs to utilize other forms of trace contact evidence, like lubricant evidence, in order to provide a link between the victim and the assailant. In this study, 90 personal bottled and condom lubricants from the three main marketing types, silicone-based, water-based and condoms, were characterized by direct analysis in real time time of flight mass spectrometry (DART-TOFMS). The instrumental data was analyzed by multivariate statistics including hierarchal cluster analysis, principal component analysis, and linear discriminant analysis. By interpreting the mass spectral data with multivariate statistics, 12 discrete groupings were identified, indicating inherent chemical diversity not only between but within the three main marketing groups. A number of unique chemical markers, both major and minor, were identified, other than the three main chemical components (i.e. PEG, PDMS and nonoxynol-9) currently used for lubricant classification. The data was validated by a stratified 20% withheld cross-validation which demonstrated that there was minimal overlap between the groupings. Based on the groupings identified and unique features of each group, a highly discriminating statistical model was then developed that aims to provide the foundation for the development of a forensic lubricant database that may eventually be applied to casework. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Improved ultra-performance liquid chromatography with electrospray ionization quadrupole-time-of-flight high-definition mass spectrometry method for the rapid analysis of the chemical constituents of a typical medical formula: Liuwei Dihuang Wan.

PubMed

Wang, Ping; Lv, Hai tao; Zhang, Ai hua; Sun, Hui; Yan, Guang li; Han, Ying; Wu, Xiu hong; Wang, Xi jun

2013-11-01

Liuwei Dihuang Wan (LDW), a classic Chinese medicinal formula, has been used to improve or restore declined functions related to aging and geriatric diseases, such as impaired mobility, vision, hearing, cognition, and memory. It has attracted increasing attention as one of the most popular and valuable herbal medicines. However, the systematic analysis of the chemical constituents of LDW is difficult and thus has not been well established. In this paper, a rapid, sensitive, and reliable ultra-performance LC with ESI quadrupole TOF high-definition MS method with automated MetaboLynx analysis in positive and negative ion mode was established to characterize the chemical constituents of LDW. The analysis was performed on a Waters UPLC™ HSS T3 using a gradient elution system. MS/MS fragmentation behavior was proposed for aiding the structural identification of the components. Under the optimized conditions, a total of 50 peaks were tentatively characterized by comparing the retention time and MS data. It is concluded that a rapid and robust platform based on ultra-performance LC with ESI quadrupole TOF high-definition MS has been successfully developed for globally identifying multiple constituents of traditional Chinese medicine prescriptions. This is the first report on the systematic analysis of the chemical constituents of LDW. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Variability of chemical analysis of reinforcing bar produced in Saudi Arabia

NASA Astrophysics Data System (ADS)

Salman, A.; Djavanroodi, F.

2018-04-01

In view of the importance and demanding roles of steel rebar’s in the reinforced concrete structures, accurate information on the properties of the steels is important at the design stage. In the steelmaking process, production variations in chemical composition are unavoidable. The aim of this work is to study the variability of the chemical composition of reinforcing steel produced throughout the Saudi Arabia and asses the quality of steel rebar’s acoording to ASTM A615. 68 samples of ASTM A615 Grade 60 from different manufacturers were collected and tested using the Spectrometer test to obtain Chemical Compositions. EasyFit (5.6) software is utilized to conducted statistical analysis. Chemical compositions distributions and, control charts are generated for the compositions. Results showed that some compositions are above the upper line of the control chart. Finally, the analyses show that less than 3% of the steel failed to meet minimum ASTM standards for chemical composition.

Quantitative Chemical Imaging and Unsupervised Analysis Using Hyperspectral Coherent Anti-Stokes Raman Scattering Microscopy

PubMed Central

2013-01-01

In this work, we report a method to acquire and analyze hyperspectral coherent anti-Stokes Raman scattering (CARS) microscopy images of organic materials and biological samples resulting in an unbiased quantitative chemical analysis. The method employs singular value decomposition on the square root of the CARS intensity, providing an automatic determination of the components above noise, which are retained. Complex CARS susceptibility spectra, which are linear in the chemical composition, are retrieved from the CARS intensity spectra using the causality of the susceptibility by two methods, and their performance is evaluated by comparison with Raman spectra. We use non-negative matrix factorization applied to the imaginary part and the nonresonant real part of the susceptibility with an additional concentration constraint to obtain absolute susceptibility spectra of independently varying chemical components and their absolute concentration. We demonstrate the ability of the method to provide quantitative chemical analysis on known lipid mixtures. We then show the relevance of the method by imaging lipid-rich stem-cell-derived mouse adipocytes as well as differentiated embryonic stem cells with a low density of lipids. We retrieve and visualize the most significant chemical components with spectra given by water, lipid, and proteins segmenting the image into the cell surrounding, lipid droplets, cytosol, and the nucleus, and we reveal the chemical structure of the cells, with details visualized by the projection of the chemical contrast into a few relevant channels. PMID:24099603

Trust, but verify: On the importance of chemical structure curation in cheminformatics and QSAR modeling research

PubMed Central

Fourches, Denis; Muratov, Eugene; Tropsha, Alexander

2010-01-01

Molecular modelers and cheminformaticians typically analyze experimental data generated by other scientists. Consequently, when it comes to data accuracy, cheminformaticians are always at the mercy of data providers who may inadvertently publish (partially) erroneous data. Thus, dataset curation is crucial for any cheminformatics analysis such as similarity searching, clustering, QSAR modeling, virtual screening, etc., especially nowadays when the availability of chemical datasets in public domain has skyrocketed in recent years. Despite the obvious importance of this preliminary step in the computational analysis of any dataset, there appears to be no commonly accepted guidance or set of procedures for chemical data curation. The main objective of this paper is to emphasize the need for a standardized chemical data curation strategy that should be followed at the onset of any molecular modeling investigation. Herein, we discuss several simple but important steps for cleaning chemical records in a database including the removal of a fraction of the data that cannot be appropriately handled by conventional cheminformatics techniques. Such steps include the removal of inorganic and organometallic compounds, counterions, salts and mixtures; structure validation; ring aromatization; normalization of specific chemotypes; curation of tautomeric forms; and the deletion of duplicates. To emphasize the importance of data curation as a mandatory step in data analysis, we discuss several case studies where chemical curation of the original “raw” database enabled the successful modeling study (specifically, QSAR analysis) or resulted in a significant improvement of model's prediction accuracy. We also demonstrate that in some cases rigorously developed QSAR models could be even used to correct erroneous biological data associated with chemical compounds. We believe that good practices for curation of chemical records outlined in this paper will be of value to all scientists working in the fields of molecular modeling, cheminformatics, and QSAR studies. PMID:20572635

Ryan M. Ness | NREL

Science.gov Websites

Interests Ryan M. Ness is a research technician in the Biomass Analysis group within the National Renewable , wet chemical analysis, and instrumental analysis of lignocellulosic biomass feedstocks. Bench-scale Publications "The Effect of Biomass Densification on Structural Sugar Release and Yield in Biofuel

Application of Surface Analysis Methods to Nanomaterials: Summaryof ISO/TC 201 Technical Report: ISO 14187:2011 -Surface Chemical Analysis- Characterization of Nanomaterials

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

Baer, Donald R.

ISO Technical Report (TR) 14187 provides an introduction to (and examples of) the information that can be obtained about nanostructured materials using surface-analysis tools. In addition, both general issues and challenges associated with characterising nanostructured materials and the specific opportunities and challenges associated with individual analytical methods are identified. As the size of objects or components of materials approaches a few nanometres, the distinctions among 'bulk', 'surface' and 'particle' analysis blur. This Technical Report focuses on issues specifically relevant to surface chemical analysis of nanostructured materials. The report considers a variety of analysis methods but focuses on techniques that aremore » in the domain of ISO/TC 201 including Auger electron spectroscopy, X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and scanning probe microscopy. Measurements of nanoparticle surface properties such as surface potential that are often made in a solution are not discussed.« less

Multivariate analysis of remote LIBS spectra using partial least squares, principal component analysis, and related techniques

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

Clegg, Samuel M; Barefield, James E; Wiens, Roger C

2008-01-01

Quantitative analysis with LIBS traditionally employs calibration curves that are complicated by the chemical matrix effects. These chemical matrix effects influence the LIBS plasma and the ratio of elemental composition to elemental emission line intensity. Consequently, LIBS calibration typically requires a priori knowledge of the unknown, in order for a series of calibration standards similar to the unknown to be employed. In this paper, three new Multivariate Analysis (MV A) techniques are employed to analyze the LIBS spectra of 18 disparate igneous and highly-metamorphosed rock samples. Partial Least Squares (PLS) analysis is used to generate a calibration model from whichmore » unknown samples can be analyzed. Principal Components Analysis (PCA) and Soft Independent Modeling of Class Analogy (SIMCA) are employed to generate a model and predict the rock type of the samples. These MV A techniques appear to exploit the matrix effects associated with the chemistries of these 18 samples.« less

Iodine Coulometry of Various Reducing Agents Including Thiols with Online Photocell Detection Coupled to a Multifunctional Chemical Analysis Station to Eliminate Student End Point Detection by Eye

ERIC Educational Resources Information Center

Padilla Mercado, Jeralyne B.; Coombs, Eri M.; De Jesus, Jenny P.; Bretz, Stacey Lowery; Danielson, Neil D.

2018-01-01

Multifunctional chemical analysis (MCA) systems provide a viable alternative for large scale instruction while supporting a hands-on approach to more advanced instrumentation. These systems are robust and typically use student stations connected to a remote central computer for data collection, minimizing the need for computers at every student…

Volatile Organic Carbon Emissions. Phase 2.

DTIC Science & Technology

1987-02-01

on sulfur (S IV) species *0. B. Nurmi, et al, "Sulfite Oxidation in Organic Acid Solutions," Flue Gas Desulfurization , American Chemical Society, 1982...in Organic Acid Solutions," Flue Gas Desulfurization , American Chemical Society, 1982, pp. 173-189. 8. Experimental Statistics; Handbook 91, United...Analysis of percentage solvent removal from absorber 49 inlet gas by Yates’ method 12. Analysis of weight percent solvent in recycle column 50 absorber

Sequence Alignment to Predict Across Species Susceptibility ...

EPA Pesticide Factsheets

Conservation of a molecular target across species can be used as a line-of-evidence to predict the likelihood of chemical susceptibility. The web-based Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) tool was developed to simplify, streamline, and quantitatively assess protein sequence/structural similarity across taxonomic groups as a means to predict relative intrinsic susceptibility. The intent of the tool is to allow for evaluation of any potential protein target, so it is amenable to variable degrees of protein characterization, depending on available information about the chemical/protein interaction and the molecular target itself. To allow for flexibility in the analysis, a layered strategy was adopted for the tool. The first level of the SeqAPASS analysis compares primary amino acid sequences to a query sequence, calculating a metric for sequence similarity (including detection of candidate orthologs), the second level evaluates sequence similarity within selected domains (e.g., ligand-binding domain, DNA binding domain), and the third level of analysis compares individual amino acid residue positions identified as being of importance for protein conformation and/or ligand binding upon chemical perturbation. Each level of the SeqAPASS analysis provides increasing evidence to apply toward rapid, screening-level assessments of probable cross species susceptibility. Such analyses can support prioritization of chemicals for further ev

Effect-directed analysis supporting monitoring of aquatic ...

EPA Pesticide Factsheets

Aquatic environments are often contaminated with complex mixtures of chemicals that may pose a risk to ecosystems and human health. This contamination cannot be addressed with target analysis alone but tools are required to reduce this complexity and identify those chemicals that might cause adverse effects. Effect-directed analysis (EDA) is designed to meet this challenge and faces increasing interest in water and sediment quality monitoring. Thus, the present paper summarizes current experience with the EDA approach and the tools required,and provides practical advice on their application. The paper highlights the need for proper problem formulation and gives general advice for study design. As the EDA approach is directed by toxicity, basic principles for the selection of bioassays are given as well as a comprehensive compilation of appropriate assays, includingtheir strengths andweaknesses. A specific focus is given to strategies for sampling, extraction and bioassay dosing since they strongly impact prioritization of toxicants in EDA. Reduction of sample complexity mainly relies onfractionation procedures, which are discussed in this paper, including quality assurance and quality control. Automated combinations of fractionation, biotesting and chemical analysis using so-called hyphenated tools can enhance the throughput and might reduce the risk of artifacts in laboratory work. The key to determiningthe chemical structures causing effects is analytical toxi

Detection of local chemical states of lithium and their spatial mapping by scanning transmission electron microscopy, electron energy-loss spectroscopy and hyperspectral image analysis.

PubMed

Muto, Shunsuke; Tatsumi, Kazuyoshi

2017-02-08

Advancements in the field of renewable energy resources have led to a growing demand for the analysis of light elements at the nanometer scale. Detection of lithium is one of the key issues to be resolved for providing guiding principles for the synthesis of cathode active materials, and degradation analysis after repeated use of those materials. We have reviewed the different techniques currently used for the characterization of light elements such as high-resolution transmission electron microscopy, scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS). In the present study, we have introduced a methodology to detect lithium in solid materials, particularly for cathode active materials used in lithium-ion battery. The chemical states of lithium were isolated and analyzed from the overlapping multiple spectral profiles, using a suite of STEM, EELS and hyperspectral image analysis. The method was successfully applied in the chemical state analyses of hetero-phases near the surface and grain boundary regions of the active material particles formed by chemical reactions between the electrolyte and the active materials. © The Author 2016. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Versatile new ion source for the analysis of materials in open air under ambient conditions.

PubMed

Cody, Robert B; Laramée, James A; Durst, H Dupont

2005-04-15

A new ion source has been developed for rapid, noncontact analysis of materials at ambient pressure and at ground potential. The new source, termed DART (for "Direct Analysis in Real Time"), is based on the reactions of electronic or vibronic excited-state species with reagent molecules and polar or nonpolar analytes. DART has been installed on a high-resolution time-of-flight mass spectrometer (TOFMS) that provides improved selectivity and accurate elemental composition assignment through exact mass measurements. Although DART has been applied to the analysis of gases, liquids, and solids, a unique application is the direct detection of chemicals on surfaces without requiring sample preparation, such as wiping or solvent extraction. DART has demonstrated success in sampling hundreds of chemicals, including chemical agents and their signatures, pharmaceutics, metabolites, peptides and oligosaccharides, synthetic organics, organometallics, drugs of abuse, explosives, and toxic industrial chemicals. These species were detected on various surfaces, such as concrete, asphalt, human skin, currency, airline boarding passes, business cards, fruits, vegetables, spices, beverages, body fluids, horticultural leaves, cocktail glasses, and clothing. DART employs no radioactive components and is more versatile than devices using radioisotope-based ionization. Because its response is instantaneous, DART provides real-time information, a critical requirement for screening or high throughput.

Evaluation of contaminant removal of reverse osmosis and advanced oxidation in full-scale operation by combining passive sampling with chemical analysis and bioanalytical tools.

PubMed

Escher, Beate I; Lawrence, Michael; Macova, Miroslava; Mueller, Jochen F; Poussade, Yvan; Robillot, Cedric; Roux, Annalie; Gernjak, Wolfgang

2011-06-15

Advanced water treatment of secondary treated effluent requires stringent quality control to achieve a water quality suitable for augmenting drinking water supplies. The removal of micropollutants such as pesticides, industrial chemicals, endocrine disrupting chemicals (EDC), pharmaceuticals, and personal care products (PPCP) is paramount. As the concentrations of individual contaminants are typically low, frequent analytical screening is both laborious and costly. We propose and validate an approach for continuous monitoring by applying passive sampling with Empore disks in vessels that were designed to slow down the water flow, and thus uptake kinetics, and ensure that the uptake is only marginally dependent on the chemicals' physicochemical properties over a relatively narrow molecular size range. This design not only assured integrative sampling over 27 days for a broad range of chemicals but also permitted the use of a suite of bioanalytical tools as sum parameters, representative of mixtures of chemicals with a common mode of toxic action. Bioassays proved to be more sensitive than chemical analysis to assess the removal of organic micropollutants by reverse osmosis, followed by UV/H₂O₂ treatment, as many individual compounds fell below the quantification limit of chemical analysis, yet still contributed to the observed mixture toxicity. Nonetheless in several cases, the responses in the bioassays were also below their quantification limits and therefore only three bioassays were evaluated here, representing nonspecific toxicity and two specific end points for estrogenicity and photosynthesis inhibition. Chemical analytical techniques were able to quantify 32 pesticides, 62 PCPPs, and 12 EDCs in reverse osmosis concentrate. However, these chemicals could explain only 1% of the nonspecific toxicity in the Microtox assay in the reverse osmosis concentrate and 0.0025% in the treated water. Likewise only 1% of the estrogenic effect in the E-SCREEN could be explained by the quantified EDCs after reverse osmosis. In comparison, >50% of the estrogenic effect can typically be explained in sewage. Herbicidal activity could be fully explained by chemical analysis as the sampling period coincided with an illegal discharge and two herbicides dominated the mixture effect. The mass balance of the reverse osmosis process matched theoretical expectations for both chemical analysis and bioanalytical tools. Overall the investigated treatment train removed >97% estrogenicity, >99% herbicidal activity, and >96% baseline toxicity, confirming the suitability of the treatment train for polishing water for indirect potable reuse. The product water was indistinguishable from local tap water in all three bioassays. This study demonstrates the suitability and robustness of passive sampling linked with bioanalytical tools for semicontinuous monitoring of advanced water treatment with respect to micropollutant removal.

Portable Solid Phase Micro-Extraction Coupled with Ion Mobility Spectrometry System for On-Site Analysis of Chemical Warfare Agents and Simulants in Water Samples

PubMed Central

Yang, Liu; Han, Qiang; Cao, Shuya; Yang, Jie; Yang, Junchao; Ding, Mingyu

2014-01-01

On-site analysis is an efficient approach to facilitate analysis at the location of the system under investigation as it can result in more accurate, more precise and quickly available analytical data. In our work, a novel self-made thermal desorption based interface was fabricated to couple solid-phase microextraction with ion mobility spectrometry for on-site water analysis. The portable interface can be connected with the front-end of an ion mobility spectrometer directly without other modifications. The analytical performance was evaluated via the extraction of chemical warfare agents and simulants in water samples. Several parameters including ionic strength and extraction time have been investigated in detail. The application of the developed method afforded satisfactory recoveries ranging from 72.9% to 114.4% when applied to the analysis of real water samples. PMID:25384006

Jet-A reaction mechanism study for combustion application

NASA Technical Reports Server (NTRS)

Lee, Chi-Ming; Kundu, Krishna; Acosta, Waldo

1991-01-01

Simplified chemical kinetic reaction mechanisms for the combustion of Jet A fuel was studied. Initially, 40 reacting species and 118 elementary chemical reactions were chosen based on a literature review. Through a sensitivity analysis with the use of LSENS General Kinetics and Sensitivity Analysis Code, 16 species and 21 elementary chemical reactions were determined from this study. This mechanism is first justified by comparison of calculated ignition delay time with the available shock tube data, then it is validated by comparison of calculated emissions from the plug flow reactor code with in-house flame tube data.

Embedded fragments from U.S. military personnel--chemical analysis and potential health implications.

PubMed

Centeno, José A; Rogers, Duane A; van der Voet, Gijsbert B; Fornero, Elisa; Zhang, Lingsu; Mullick, Florabel G; Chapman, Gail D; Olabisi, Ayodele O; Wagner, Dean J; Stojadinovic, Alexander; Potter, Benjamin K

2014-01-23

The majority of modern war wounds are characterized by high-energy blast injuries containing a wide range of retained foreign materials of a metallic or composite nature. Health effects of retained fragments range from local or systemic toxicities to foreign body reactions or malignancies, and dependent on the chemical composition and corrosiveness of the fragments in vivo. Information obtained by chemical analysis of excised fragments can be used to guide clinical decisions regarding the need for fragment removal, to develop therapeutic interventions, and to better anticipate future medical problems from retained fragment related injuries. In response to this need, a new U.S Department of Defense (DoD) directive has been issued requiring characterization of all removed fragments to provide a database of fragment types occurring in combat injuries. The objective of this study is to determine the chemical composition of retained embedded fragments removed from injured military personnel, and to relate results to histological findings in tissue adjacent to fragment material. We describe an approach for the chemical analysis and characterization of retained fragments and adjacent tissues, and include case examples describing fragments containing depleted uranium (DU), tungsten (W), lead (Pb), and non-metal foreign bodies composed of natural and composite materials. Fragments obtained from four patients with penetrating blast wounds to the limbs were studied employing a wide range of chemical and microscopy techniques. Available adjacent tissues from three of the cases were histologically, microscopically, and chemically examined. The physical and compositional properties of the removed foreign material surfaces were examined with energy dispersive x-ray fluorescence spectrometry (EDXRF), scanning electron microscopy (SEM), laser ablation inductively-coupled plasma mass-spectrometry (LA-ICP-MS), and confocal laser Raman microspectroscopy (CLRM). Quantitative chemical analysis of both fragments and available tissues was conducted employing ICP-MS. Over 800 fragments have been characterized and included as part of the Joint Pathology Center Embedded Fragment Registry. Most fragments were obtained from penetrating wounds sustained to the extremities, particularly soft tissue injuries. The majority of the fragments were primarily composed of a single metal such as iron, copper, or aluminum with traces of antimony, titanium, uranium, and lead. One case demonstrated tungsten in both the fragment and the connected tissue, together with lead. Capsular tissue and fragments from a case from the 1991 Kuwait conflict showed evidence of uranium that was further characterized by uranium isotopic ratios analysis to contain depleted uranium. The present study provides a systematic approach for obtaining a full chemical characterization of retained embedded fragments. Given the vast number of combat casualties with retained fragments, it is expected that fragment analysis will have significant implications for the optimal short and long-term care of wounded service members.

Embedded Fragments from U.S. Military Personnel—Chemical Analysis and Potential Health Implications

PubMed Central

Centeno, José A.; Rogers, Duane A.; van der Voet, Gijsbert B.; Fornero, Elisa; Zhang, Lingsu; Mullick, Florabel G.; Chapman, Gail D.; Olabisi, Ayodele O.; Wagner, Dean J.; Stojadinovic, Alexander; Potter, Benjamin K.

2014-01-01

Background: The majority of modern war wounds are characterized by high-energy blast injuries containing a wide range of retained foreign materials of a metallic or composite nature. Health effects of retained fragments range from local or systemic toxicities to foreign body reactions or malignancies, and dependent on the chemical composition and corrosiveness of the fragments in vivo. Information obtained by chemical analysis of excised fragments can be used to guide clinical decisions regarding the need for fragment removal, to develop therapeutic interventions, and to better anticipate future medical problems from retained fragment related injuries. In response to this need, a new U.S Department of Defense (DoD) directive has been issued requiring characterization of all removed fragments to provide a database of fragment types occurring in combat injuries. Objectives: The objective of this study is to determine the chemical composition of retained embedded fragments removed from injured military personnel, and to relate results to histological findings in tissue adjacent to fragment material. Methods: We describe an approach for the chemical analysis and characterization of retained fragments and adjacent tissues, and include case examples describing fragments containing depleted uranium (DU), tungsten (W), lead (Pb), and non-metal foreign bodies composed of natural and composite materials. Fragments obtained from four patients with penetrating blast wounds to the limbs were studied employing a wide range of chemical and microscopy techniques. Available adjacent tissues from three of the cases were histologically, microscopically, and chemically examined. The physical and compositional properties of the removed foreign material surfaces were examined with energy dispersive x-ray fluorescence spectrometry (EDXRF), scanning electron microscopy (SEM), laser ablation inductively-coupled plasma mass-spectrometry (LA-ICP-MS), and confocal laser Raman microspectroscopy (CLRM). Quantitative chemical analysis of both fragments and available tissues was conducted employing ICP-MS. Results: Over 800 fragments have been characterized and included as part of the Joint Pathology Center Embedded Fragment Registry. Most fragments were obtained from penetrating wounds sustained to the extremities, particularly soft tissue injuries. The majority of the fragments were primarily composed of a single metal such as iron, copper, or aluminum with traces of antimony, titanium, uranium, and lead. One case demonstrated tungsten in both the fragment and the connected tissue, together with lead. Capsular tissue and fragments from a case from the 1991 Kuwait conflict showed evidence of uranium that was further characterized by uranium isotopic ratios analysis to contain depleted uranium. Conclusions: The present study provides a systematic approach for obtaining a full chemical characterization of retained embedded fragments. Given the vast number of combat casualties with retained fragments, it is expected that fragment analysis will have significant implications for the optimal short and long-term care of wounded service members. PMID:24464236

Estimation of environment-related properties of chemicals for design of sustainable processes: development of group-contribution+ (GC+) property models and uncertainty analysis.

PubMed

Hukkerikar, Amol Shivajirao; Kalakul, Sawitree; Sarup, Bent; Young, Douglas M; Sin, Gürkan; Gani, Rafiqul

2012-11-26

The aim of this work is to develop group-contribution(+) (GC(+)) method (combined group-contribution (GC) method and atom connectivity index (CI) method) based property models to provide reliable estimations of environment-related properties of organic chemicals together with uncertainties of estimated property values. For this purpose, a systematic methodology for property modeling and uncertainty analysis is used. The methodology includes a parameter estimation step to determine parameters of property models and an uncertainty analysis step to establish statistical information about the quality of parameter estimation, such as the parameter covariance, the standard errors in predicted properties, and the confidence intervals. For parameter estimation, large data sets of experimentally measured property values of a wide range of chemicals (hydrocarbons, oxygenated chemicals, nitrogenated chemicals, poly functional chemicals, etc.) taken from the database of the US Environmental Protection Agency (EPA) and from the database of USEtox is used. For property modeling and uncertainty analysis, the Marrero and Gani GC method and atom connectivity index method have been considered. In total, 22 environment-related properties, which include the fathead minnow 96-h LC(50), Daphnia magna 48-h LC(50), oral rat LD(50), aqueous solubility, bioconcentration factor, permissible exposure limit (OSHA-TWA), photochemical oxidation potential, global warming potential, ozone depletion potential, acidification potential, emission to urban air (carcinogenic and noncarcinogenic), emission to continental rural air (carcinogenic and noncarcinogenic), emission to continental fresh water (carcinogenic and noncarcinogenic), emission to continental seawater (carcinogenic and noncarcinogenic), emission to continental natural soil (carcinogenic and noncarcinogenic), and emission to continental agricultural soil (carcinogenic and noncarcinogenic) have been modeled and analyzed. The application of the developed property models for the estimation of environment-related properties and uncertainties of the estimated property values is highlighted through an illustrative example. The developed property models provide reliable estimates of environment-related properties needed to perform process synthesis, design, and analysis of sustainable chemical processes and allow one to evaluate the effect of uncertainties of estimated property values on the calculated performance of processes giving useful insights into quality and reliability of the design of sustainable processes.

Profiling and multivariate statistical analysis of Panax ginseng based on ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry.

PubMed

Wu, Wei; Sun, Le; Zhang, Zhe; Guo, Yingying; Liu, Shuying

2015-03-25

An ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) method was developed for the detection and structural analysis of ginsenosides in white ginseng and related processed products (red ginseng). Original neutral, malonyl, and chemically transformed ginsenosides were identified in white and red ginseng samples. The aglycone types of ginsenosides were determined by MS/MS as PPD (m/z 459), PPT (m/z 475), C-24, -25 hydrated-PPD or PPT (m/z 477 or m/z 493), and Δ20(21)-or Δ20(22)-dehydrated-PPD or PPT (m/z 441 or m/z 457). Following the structural determination, the UHPLC-Q-TOF-MS-based chemical profiling coupled with multivariate statistical analysis method was applied for global analysis of white and processed ginseng samples. The chemical markers present between the processed products red ginseng and white ginseng could be assigned. Process-mediated chemical changes were recognized as the hydrolysis of ginsenosides with large molecular weight, chemical transformations of ginsenosides, changes in malonyl-ginsenosides, and generation of 20-(R)-ginsenoside enantiomers. The relative contents of compounds classified as PPD, PPT, malonyl, and transformed ginsenosides were calculated based on peak areas in ginseng before and after processing. This study provides possibility to monitor multiple components for the quality control and global evaluation of ginseng products during processing. Copyright © 2014 Elsevier B.V. All rights reserved.

Physico-chemical and biological characterization of urban municipal landfill leachate.

PubMed

Naveen, B P; Mahapatra, Durga Madhab; Sitharam, T G; Sivapullaiah, P V; Ramachandra, T V

2017-01-01

Unscientific management and ad-hoc approaches in municipal solid waste management have led to a generation of voluminous leachate in urban conglomerates. Quantification, quality assessment, following treatment and management of leachate has become a serious problem worldwide. In this context, the present study investigates the physico-chemical and biological characterization of landfill leachate and nearby water sources and attempts to identify relationships between the key parameters together with understanding the various processes for chemical transformations. The analysis shows an intermediate leachate age (5-10 years) with higher nutrient levels of 10,000-12,000 mg/l and ∼2000-3000 mg/l of carbon (COD) and nitrogen (TKN) respectively. Elemental analysis and underlying mechanisms reveal chemical precipitation and co-precipitation as the vital processes in leachate pond systems resulting in accumulation of trace metals. Based on the above criteria the samples were clustered into major groups that showed a clear distinction between leachate and water bodies. The microbial analysis showed bacterial communities correlating with specific factors relevant to redox environments indicating a gradient in nature and abundance of biotic diversity with a change in leachate environment. Finally, the quality and the contamination potential of the samples were evaluated with the help of leachate pollution index (LPI) and water quality index (WQI) analysis. The study helps in understanding the contamination potential of landfill leachate and establishes linkages between microbial communities and physico-chemical parameters for effective management of landfill leachate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Combinations of NIR, Raman spectroscopy and physicochemical measurements for improved monitoring of solvent extraction processes using hierarchical multivariate analysis models

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

Nee, K.; Bryan, S.; Levitskaia, T.

The reliability of chemical processes can be greatly improved by implementing inline monitoring systems. Combining multivariate analysis with non-destructive sensors can enhance the process without interfering with the operation. Here, we present here hierarchical models using both principal component analysis and partial least square analysis developed for different chemical components representative of solvent extraction process streams. A training set of 380 samples and an external validation set of 95 samples were prepared and Near infrared and Raman spectral data as well as conductivity under variable temperature conditions were collected. The results from the models indicate that careful selection of themore » spectral range is important. By compressing the data through Principal Component Analysis (PCA), we lower the rank of the data set to its most dominant features while maintaining the key principal components to be used in the regression analysis. Within the studied data set, concentration of five chemical components were modeled; total nitrate (NO 3 -), total acid (H +), neodymium (Nd 3+), sodium (Na +), and ionic strength (I.S.). The best overall model prediction for each of the species studied used a combined data set comprised of complementary techniques including NIR, Raman, and conductivity. Finally, our study shows that chemometric models are powerful but requires significant amount of carefully analyzed data to capture variations in the chemistry.« less

Mini-DIAL system measurements coupled with multivariate data analysis to identify TIC and TIM simulants: preliminary absorption database analysis.

NASA Astrophysics Data System (ADS)

Gaudio, P.; Malizia, A.; Gelfusa, M.; Martinelli, E.; Di Natale, C.; Poggi, L. A.; Bellecci, C.

2017-01-01

Nowadays Toxic Industrial Components (TICs) and Toxic Industrial Materials (TIMs) are one of the most dangerous and diffuse vehicle of contamination in urban and industrial areas. The academic world together with the industrial and military one are working on innovative solutions to monitor the diffusion in atmosphere of such pollutants. In this phase the most common commercial sensors are based on “point detection” technology but it is clear that such instruments cannot satisfy the needs of the smart cities. The new challenge is developing stand-off systems to continuously monitor the atmosphere. Quantum Electronics and Plasma Physics (QEP) research group has a long experience in laser system development and has built two demonstrators based on DIAL (Differential Absorption of Light) technology could be able to identify chemical agents in atmosphere. In this work the authors will present one of those DIAL system, the miniaturized one, together with the preliminary results of an experimental campaign conducted on TICs and TIMs simulants in cell with aim of use the absorption database for the further atmospheric an analysis using the same DIAL system. The experimental results are analysed with standard multivariate data analysis technique as Principal Component Analysis (PCA) to develop a classification model aimed at identifying organic chemical compound in atmosphere. The preliminary results of absorption coefficients of some chemical compound are shown together pre PCA analysis.

Rapid Analysis of Corni fructus Using Paper Spray-Mass Spectrometry.

PubMed

Guo, Yuan; Gu, Zhixin; Liu, Xuemei; Liu, Jingjing; Ma, Ming; Chen, Bo; Wang, Liping

2017-07-01

Paper spray-mass spectrometry (PS-MS) is a kind of ambient MS technique for the rapid analysis of samples. Corni fructus has been widely used in traditional Chinese compound preparations and healthy food. However, a number of counterfeits of Corni fructus, such as Crataegi fructus, Lycii fructus, and grape skin are illegally sold in crude herb markets. Therefore, the development of a rapid and high-throughput quality evaluation method is important for ensuring the effectiveness and safety of the crude materials of Corni fructus. To develop PS-MS chemical profiles and a semi-quantitative method of Corni fructus for quality assessment and control, and species distinction of Corni fructus. Both positive and negative ion PS-MS chemical profiles were constructed for species distinction. The statistical analysis of the chemical profiles was accomplished by principal component analysis (PCA). Rapid semi-quantitative analysis of loganin and morroniside in the extracts of Corni fructus were accomplished by PS-MS. The profiles of the Corni fructus and Crataegi fructus samples were clearly clustered into two categories. The limit of quantification (LOQ) in the semi-quantitative analysis was 6 μg/mL and 5.6 μg/mL for loganin and morroniside, respectively. PS-MS is a simple, rapid, and high-throughput method for the quality control and species distinction of Corni fructus. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Combinations of NIR, Raman spectroscopy and physicochemical measurements for improved monitoring of solvent extraction processes using hierarchical multivariate analysis models

DOE PAGES

Nee, K.; Bryan, S.; Levitskaia, T.; ...

2017-12-28

The reliability of chemical processes can be greatly improved by implementing inline monitoring systems. Combining multivariate analysis with non-destructive sensors can enhance the process without interfering with the operation. Here, we present here hierarchical models using both principal component analysis and partial least square analysis developed for different chemical components representative of solvent extraction process streams. A training set of 380 samples and an external validation set of 95 samples were prepared and Near infrared and Raman spectral data as well as conductivity under variable temperature conditions were collected. The results from the models indicate that careful selection of themore » spectral range is important. By compressing the data through Principal Component Analysis (PCA), we lower the rank of the data set to its most dominant features while maintaining the key principal components to be used in the regression analysis. Within the studied data set, concentration of five chemical components were modeled; total nitrate (NO 3 -), total acid (H +), neodymium (Nd 3+), sodium (Na +), and ionic strength (I.S.). The best overall model prediction for each of the species studied used a combined data set comprised of complementary techniques including NIR, Raman, and conductivity. Finally, our study shows that chemometric models are powerful but requires significant amount of carefully analyzed data to capture variations in the chemistry.« less

21 CFR 1304.23 - Records for chemical analysts.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 9 2011-04-01 2011-04-01 false Records for chemical analysts. 1304.23 Section... REGISTRANTS Continuing Records § 1304.23 Records for chemical analysts. (a) Each person registered or authorized (by § 1301.22(b) of this chapter) to conduct chemical analysis with controlled substances shall...

21 CFR 1304.23 - Records for chemical analysts.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Records for chemical analysts. 1304.23 Section... REGISTRANTS Continuing Records § 1304.23 Records for chemical analysts. (a) Each person registered or authorized (by § 1301.22(b) of this chapter) to conduct chemical analysis with controlled substances shall...

[New approaches to early diagnosis of chronic organophosphorus chemicals intoxication in workers at chemical weapons extermination objects].

PubMed

Babakov, V N; Goncharov, N V; Radilov, A S; Glashkina, E P; Podol'skaia, E P; Ermolaeva, E E; Shilov, V V; Prokof'eva, D S; Voĭtenko, N G; Egorov, N A

2009-01-01

Mass spectrum analysis revealed differences in general contents of low-molecular peptides spectrums in chemical weapons extermination object staffers, in comparison with the reference group. Findings are that serum paraoxonase activity in chemical weapons extermination object staffers in significantly increased.

21 CFR 1304.23 - Records for chemical analysts.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 9 2012-04-01 2012-04-01 false Records for chemical analysts. 1304.23 Section... REGISTRANTS Continuing Records § 1304.23 Records for chemical analysts. (a) Each person registered or authorized (by § 1301.22(b) of this chapter) to conduct chemical analysis with controlled substances shall...

21 CFR 1304.23 - Records for chemical analysts.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 9 2014-04-01 2014-04-01 false Records for chemical analysts. 1304.23 Section... REGISTRANTS Continuing Records § 1304.23 Records for chemical analysts. (a) Each person registered or authorized (by § 1301.22(b) of this chapter) to conduct chemical analysis with controlled substances shall...

Summaries of FY 1980 research in the chemical sciences

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

None

1980-09-01

Brief summaries are given of research programs being pursued by DOE laboratories and offsite facilities in the fields of photochemical and radiation sciences, chemical physics, atomic physics, chemical energy, separations, analysis, and chemical engineering sciences. No actual data is given. Indexes of topics, offsite institutions, and investigators are included. (DLC)

40 CFR 720.36 - Exemption for research and development.

Code of Federal Regulations, 2014 CFR

2014-07-01

... development. (a) This part does not apply to a chemical substance if the following conditions are met: (1) The chemical substance is manufactured or imported only in small quantities solely for research and development... distributes the chemical substance, who are engaged in experimentation, research, or analysis on the chemical...

40 CFR 720.36 - Exemption for research and development.

Code of Federal Regulations, 2013 CFR

2013-07-01

... development. (a) This part does not apply to a chemical substance if the following conditions are met: (1) The chemical substance is manufactured or imported only in small quantities solely for research and development... distributes the chemical substance, who are engaged in experimentation, research, or analysis on the chemical...

40 CFR 720.36 - Exemption for research and development.

Code of Federal Regulations, 2012 CFR

2012-07-01

... development. (a) This part does not apply to a chemical substance if the following conditions are met: (1) The chemical substance is manufactured or imported only in small quantities solely for research and development... distributes the chemical substance, who are engaged in experimentation, research, or analysis on the chemical...

40 CFR 720.36 - Exemption for research and development.

Code of Federal Regulations, 2011 CFR

2011-07-01

... development. (a) This part does not apply to a chemical substance if the following conditions are met: (1) The chemical substance is manufactured or imported only in small quantities solely for research and development... distributes the chemical substance, who are engaged in experimentation, research, or analysis on the chemical...

Performance Objectives, Task Analysis, Learning Content, Content Limits, and Domain Referenced Tests for the Agricultural Chemicals Catalog. Final Report.

ERIC Educational Resources Information Center

Hamilton, William; And Others

This document contains Indiana agricultural chemicals curriculum materials based on the Vocational-Technical Education Consortium of States (VTECS) Agricultural Chemicals Catalog. It is intended to improve preparation of high school and adult students for handling and using agricultural chemicals and for jobs as chemical salespersons or chemical…

ANALYSIS OF SELECTED CHEMICAL GROUPS BY LIQUID CHROMATOGRAPHY/MASS SPECTROMETRY

EPA Science Inventory

The use of the moving-belt liquid chromatographic interface in combination with mass spectrometry was evaluated for determining detection limits of selected members of various chemical classes. mong the chemical classes examined were benzidines, nitrosoamines, anilines, nitroarom...

Feature Analysis of ToxCast Compounds

EPA Science Inventory

ToxCast was initiated by the US Environmental Protection Agency (EPA) to prioritize environmental chemicals for toxicity testing. Phase I generated data for 309 unique chemicals, mostly pesticide actives, that span diverse chemical feature/property space, as determined by quantu...

Analysis of Hydraulic Fracturing Fluid Data from the FracFocus Chemical Disclosure Registry 1

EPA Pesticide Factsheets

The EPA analyzed data from the FracFocus Chemical Disclosure Registry 1.0 to better understand the chemicals and water used to hydraulically fracture oil and gas production wells across the United States.

Chemical warfare, past and future. Study project

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

Tzihor, A.

1992-05-15

World War I was arena for the first use of chemical warfare. The enormous tactical success brought about by this first time use of chemical weapons caused the continued development of more sophisticated tactics and weapons in this category of unconventional warfare. This phenomenon has carried through to today. However, at present, because of technological developments, the global economic situation, and political factors, coupled with the inability of the western world to control the proliferation of chemical weapons, a situation weapon of mass destruction. Recent use by Iraq against Kurdish civilian indicates that chemical warfare is no longer limited tomore » the battlefield. The western nations have a need to understand the risk. This paper conducts an analysis of past lessons and the factors which will affect the use of chemical warfare in the future. From this analysis, the paper reaches conclusions concerning the significant threat chemical weapons pose for the entire world in the not too distant future.« less

Chemical, biochemical, and environmental fiber sensors III; Proceedings of the Meeting, Boston, MA, Sept. 4, 5, 1991

NASA Astrophysics Data System (ADS)

Lieberman, Robert A.

Various papers on chemical, biochemical, and environmental fiber sensors are presented. Individual topics addressed include: fiber optic pressure sensor for combustion monitoring and control, viologen-based fiber optic oxygen sensors, renewable-reagent fiber optic sensor for ocean pCO2, transition metal complexes as indicators for a fiber optic oxygen sensor, fiber optic pH measurements using azo indicators, simple reversible fiber optic chemical sensors using solvatochromic dyes, totally integrated optical measuring sensors, integrated optic biosensor for environmental monitoring, radiation dosimetry using planar waveguide sensors, optical and piezoelectric analysis of polymer films for chemical sensor characterization, source polarization effects in an optical fiber fluorosensor, lens-type refractometer for on-line chemical analysis, fiber optic hydrocarbon sensor system, chemical sensors for environmental monitoring, optical fibers for liquid-crystal sensing and logic devices, suitability of single-mode fluoride fibers for evanescent-wave sensing, integrated modules for fiber optic sensors, optoelectronic sensors based on narrowband A3B5 alloys, fiber Bragg grating chemical sensor.

7 CFR 160.1 - Definitions of general terms.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) Analysis. Any examination by physical, chemical, or sensory methods. (m) Classification. Designation as to... Administrator has sufficient and proper interest in the analysis, classification, grading, or sale of naval... provisions of the act and the provisions in this part to show the results of any examination, analysis...

Qualitative and quantitative analysis of lignocellulosic biomass using infrared techniques: A mini-review

USDA-ARS?s Scientific Manuscript database

Current wet chemical methods for biomass composition analysis using two-step sulfuric acid hydrolysis are time-consuming, labor-intensive, and unable to provide structural information about biomass. Infrared techniques provide fast, low-cost analysis, are non-destructive, and have shown promising re...

Photoacoustic biopsy: a feasibility study

NASA Astrophysics Data System (ADS)

Xu, Guan; Tomlins, Scott A.; Siddiqui, Javed; Davis, Mandy A.; Kunju, Lakshmi P.; Wei, John T.; Wang, Xueding

2015-03-01

Photoacoustic (PA) measurements encode the information associated with both physical microstructures and chemical contents in biological tissues. A two-dimensional physio-chemical spectrogram (PCS) can be formulated by combining the power spectra of PA signals acquired at a series of optical wavelengths. The analysis of PCS, or namely PA physio-chemical analysis (PAPCA), enables the quantification of the concentrations and the spatial distributions of a variety of chemical components in the tissue. The chemical components and their distribution are the two major features observed in the biopsy procedures which have been regarded as the gold standard of the diagnosis of many diseases. Taking non-alcoholic fatty liver disease and prostate cancer for example, this study investigates the feasibility of PAPCA in characterizing the histopathological changes in the diseased conditions in biological tissue. A catheter based setup facilitating measurement in deep tissues was also proposed and tested.

Utilization of biosensors and chemical sensors for space applications

NASA Technical Reports Server (NTRS)

Bonting, S. L.

1992-01-01

There will be a need for a wide array of chemical sensors for biomedical experimentation and for the monitoring of water and air recycling processes on Space Station Freedom. The infrequent logistics flights of the Space Shuttle will necessitate onboard analysis. The advantages of biosensors and chemical sensors over conventional analysis onboard spacecraft are manifold. They require less crew time, space, and power. Sample treatment is not needed. Real time or near-real time monitoring is possible, in some cases on a continuous basis. Sensor signals in digitized form can be transmitted to the ground. Types and requirements for chemical sensors to be used in biomedical experimentation and monitoring of water recycling during long-term space missions are discussed.

Diagnostic studies of the HxOy-NzOy-O3 photochemical system using data from NASA GTE field expeditions

NASA Technical Reports Server (NTRS)

Chameides, William L.

1988-01-01

Spring 1084 GTE CITE-1 flight data from the field exercise was obtained from a GTE Data Archive Tape. Chemical and supporting meteorological data taken over the Pacific Ocean was statistically and diagnostically analyzed to identify the key processes affecting the concentrations of ozone and its chemical precursors in the region. The analysis was completed. The analysis of the GTE CITE-2 data is being performed in collaboration with Dr. D.D. Davis and other GTE scientists. Initial results of the analysis were presented and work begun on the paper describing the results.

Analysis of Asian Outflow over the Western Pacific using Observations from Trace-P

NASA Technical Reports Server (NTRS)

Jacob, Daniel J.

2004-01-01

Our analysis of the TRACE-P data focused on answering the following questions: 1) How do anthropogenic sources in Asia contribute to chemical outflow over the western Pacific in spring? 2) How does biomass burning in southeast Asia contribute to this outflow? 3) How can the TRACE-P observations be used to better quantify the sources of environmentally important gases in eastern Asia? Our strategy drew on a combination of data analysis and global 3-D modeling, as described below. We also contributed to the planning and execution of TRACE-P through service as mission scientist and by providing chemical model forecasts in the field.

A protocol for chemical mutagenesis in Strongyloides ratti.

PubMed

Guo, Li; Chang, Zisong; Dieterich, Christoph; Streit, Adrian

2015-11-01

Genetic analysis using experimentally induced mutations has been a most valuable tool in the analysis of various organisms. However, genetic analysis of endoparasitic organisms tends to be difficult because of the limited accessibility of the sexually reproducing adults, which are normally located within the host. Nematodes of the genera Strogyloides and Parastrongyloides represent an exception to this because they can form facultative free-living sexually reproducing generations in between parasitic generations. Here we present a protocol for the chemical mutagenesis of Strongyloides ratti. Further we evaluate the feasibility of identifying the induced mutations by whole genome re-sequencing. Copyright © 2015 Elsevier Inc. All rights reserved.

Analysis of digester design concepts

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

Ashare, E.; Wilson, E. H.

1979-01-29

Engineering economic analyses were performed on various digester design concepts to determine the relative performance for various biomass feedstocks. A comprehensive literature survey describing the state-of-the-art of the various digestion designs is included. The digester designs included in the analyses are CSTR, plug flow, batch, CSTR in series, multi-stage digestion and biomethanation. Other process options investigated included pretreatment processes such as shredding, degritting, and chemical pretreatment, and post-digestion processes, such as dewatering and gas purification. The biomass sources considered include feedlot manure, rice straw, and bagasse. The results of the analysis indicate that the most economical (on a unit gasmore » cost basis) digester design concept is the plug flow reactor. This conclusion results from this system providing a high gas production rate combined with a low capital hole-in-the-ground digester design concept. The costs determined in this analysis do not include any credits or penalties for feedstock or by-products, but present the costs only for conversion of biomass to methane. The batch land-fill type digester design was shown to have a unit gas cost comparable to that for a conventional stirred tank digester, with the potential of reducing the cost if a land-fill site were available for a lower cost per unit volume. The use of chemical pretreatment resulted in a higher unit gas cost, primarily due to the cost of pretreatment chemical. A sensitivity analysis indicated that the use of chemical pretreatment could improve the economics provided a process could be developed which utilized either less pretreatment chemical or a less costly chemical. The use of other process options resulted in higher unit gas costs. These options should only be used when necessary for proper process performance, or to result in production of a valuable by-product.« less

LSENS, A General Chemical Kinetics and Sensitivity Analysis Code for Homogeneous Gas-Phase Reactions. Part 2; Code Description and Usage

NASA Technical Reports Server (NTRS)

Radhakrishnan, Krishnan; Bittker, David A.

1994-01-01

LSENS, the Lewis General Chemical Kinetics and Sensitivity Analysis Code, has been developed for solving complex, homogeneous, gas-phase chemical kinetics problems and contains sensitivity analysis for a variety of problems, including nonisothermal situations. This report is part II of a series of three reference publications that describe LSENS, provide a detailed guide to its usage, and present many example problems. Part II describes the code, how to modify it, and its usage, including preparation of the problem data file required to execute LSENS. Code usage is illustrated by several example problems, which further explain preparation of the problem data file and show how to obtain desired accuracy in the computed results. LSENS is a flexible, convenient, accurate, and efficient solver for chemical reaction problems such as static system; steady, one-dimensional, inviscid flow; reaction behind incident shock wave, including boundary layer correction; and perfectly stirred (highly backmixed) reactor. In addition, the chemical equilibrium state can be computed for the following assigned states: temperature and pressure, enthalpy and pressure, temperature and volume, and internal energy and volume. For static problems the code computes the sensitivity coefficients of the dependent variables and their temporal derivatives with respect to the initial values of the dependent variables and/or the three rate coefficient parameters of the chemical reactions. Part I (NASA RP-1328) derives the governing equations and describes the numerical solution procedures for the types of problems that can be solved by LSENS. Part III (NASA RP-1330) explains the kinetics and kinetics-plus-sensitivity-analysis problems supplied with LSENS and presents sample results.

Uses of NHANES Biomarker Data for Chemical Risk Assessment: Trends, Challenges, and Opportunities

PubMed Central

DeWoskin, Robert S.; Tan, Yu-Mei; Pleil, Joachim D.; Phillips, Martin Blake; George, Barbara Jane; Christensen, Krista; Schreinemachers, Dina M.; Williams, Marc A.; Hubal, Elaine A. Cohen; Edwards, Stephen W.

2015-01-01

Background Each year, the U.S. NHANES measures hundreds of chemical biomarkers in samples from thousands of study participants. These biomarker measurements are used to establish population reference ranges, track exposure trends, identify population subsets with elevated exposures, and prioritize research needs. There is now interest in further utilizing the NHANES data to inform chemical risk assessments. Objectives This article highlights a) the extent to which U.S. NHANES chemical biomarker data have been evaluated, b) groups of chemicals that have been studied, c) data analysis approaches and challenges, and d) opportunities for using these data to inform risk assessments. Methods A literature search (1999–2013) was performed to identify publications in which U.S. NHANES data were reported. Manual curation identified only the subset of publications that clearly utilized chemical biomarker data. This subset was evaluated for chemical groupings, data analysis approaches, and overall trends. Results A small percentage of the sampled NHANES-related publications reported on chemical biomarkers (8% yearly average). Of 11 chemical groups, metals/metalloids were most frequently evaluated (49%), followed by pesticides (9%) and environmental phenols (7%). Studies of multiple chemical groups were also common (8%). Publications linking chemical biomarkers to health metrics have increased dramatically in recent years. New studies are addressing challenges related to NHANES data interpretation in health risk contexts. Conclusions This article demonstrates growing use of NHANES chemical biomarker data in studies that can impact risk assessments. Best practices for analysis and interpretation must be defined and adopted to allow the full potential of NHANES to be realized. Citation Sobus JR, DeWoskin RS, Tan YM, Pleil JD, Phillips MB, George BJ, Christensen K, Schreinemachers DM, Williams MA, Cohen Hubal EA, Edwards SW. 2015. Uses of NHANES biomarker data for chemical risk assessment: trends, challenges, and opportunities. Environ Health Perspect 123:919–927; http://dx.doi.org/10.1289/ehp.1409177 PMID:25859901

Cheminformatic Analysis of the US EPA ToxCast Chemical Library

EPA Science Inventory

The ToxCast project is employing high throughput screening (HTS) technologies, along with chemical descriptors and computational models, to develop approaches for screening and prioritizing environmental chemicals for further toxicity testing. ToxCast Phase I generated HTS data f...

Analysis of Hydraulic Fracturing Fluid Data from the FracFocus Chemical Disclosure Registry 1 (PDF)

EPA Pesticide Factsheets

The EPA analyzed data from the FracFocus Chemical Disclosure Registry 1.0 to better understand the chemicals and water used to hydraulically fracture oil and gas production wells across the United States.

Failure Analysis of the Main Rotor Retention Nut from AH-64 Helicopter

DTIC Science & Technology

1992-06-01

corrosion , and electrochemical tests. The chemi- cal composition of the steel was well within the contractors specification and met the in- dustry standards...1. Additionally, the contractor specification meets the industry standards for the chemical composition for maraging C-250 grade steel . Table 1...metallographic analy- sis of both failed and intact nuts; chemical analysis of the 18 Ni maraging steel C-250 grade steel ; mechanical property, stress

Multi-component quantitation of meso/nanostructural surfaces and its application to local chemical compositions of copper meso/nanostructures self-organized on silica

NASA Astrophysics Data System (ADS)

Huang, Chun-Yi; Chang, Hsin-Wei; Chang, Che-Chen

2018-03-01

Knowledge about the chemical compositions of meso/nanomaterials is fundamental to development of their applications in advanced technologies. Auger electron spectroscopy (AES) is an effective analysis method for the characterization of meso/nanomaterial structures. Although a few studies have reported the use of AES for the analysis of the local composition of these structures, none have explored in detail the validity of the meso/nanoanalysis results generated by the AES instrument. This paper addresses the limitations of AES and the corrections necessary to offset them for this otherwise powerful meso/nanoanalysis tool. The results of corrections made to the AES multi-point analysis of high-density copper-based meso/nanostructures provides major insights into their local chemical compositions and technological prospects, which the primitive composition output of the AES instrument failed to provide.

Substituent effect study on experimental ¹³C NMR chemical shifts of (3-(substituted phenyl)-cis-4,5-dihydroisoxazole-4,5-diyl)bis(methylene)diacetate derivatives.

PubMed

Kara, Yesim S

2015-12-05

Eleven novel (3-(substituted phenyl)-cis-4,5-dihydroisoxazole-4,5-diyl)bis(methylene) diacetate derivatives were synthesized in the present study. These dihydroisoxazole derivatives were characterized by IR, (1)H NMR, (13)C NMR and elemental analyses. Their (13)C NMR spectra were measured in Deuterochloroform (CDCl3). The correlation analysis for the substituent-induced chemical shift (SCS) with Hammett substituent constant (σ), inductive substituent constant (σI), different of resonance substituent constants (σR, σR(o)) and Swain-Lupton substituent parameters (F, R) were performed using SSP (single substituent parameter), and DSP (dual substituent parameter) methods, as well as single and multiple regression analysis. From the result of regression analysis, the effect of substituent on the (13)C NMR chemical shifts was explained. Copyright © 2015 Elsevier B.V. All rights reserved.

Flow chemistry vs. flow analysis.

PubMed

Trojanowicz, Marek

2016-01-01

The flow mode of conducting chemical syntheses facilitates chemical processes through the use of on-line analytical monitoring of occurring reactions, the application of solid-supported reagents to minimize downstream processing and computerized control systems to perform multi-step sequences. They are exactly the same attributes as those of flow analysis, which has solid place in modern analytical chemistry in several last decades. The following review paper, based on 131 references to original papers as well as pre-selected reviews, presents basic aspects, selected instrumental achievements and developmental directions of a rapidly growing field of continuous flow chemical synthesis. Interestingly, many of them might be potentially employed in the development of new methods in flow analysis too. In this paper, examples of application of flow analytical measurements for on-line monitoring of flow syntheses have been indicated and perspectives for a wider application of real-time analytical measurements have been discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

40 CFR 68.67 - Process hazard analysis.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) CHEMICAL ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.67 Process hazard analysis. (a... instrumentation with alarms, and detection hardware such as hydrocarbon sensors.); (4) Consequences of failure of...

40 CFR 68.67 - Process hazard analysis.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) CHEMICAL ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.67 Process hazard analysis. (a... instrumentation with alarms, and detection hardware such as hydrocarbon sensors.); (4) Consequences of failure of...

Demonstration and Evaluation of Solid Phase Microextraction for the Assessment of Bioavailability and Contaminant Mobility

DTIC Science & Technology

2012-05-01

methods demonstrated that desorption into solvents suitable for subsequent chemical analysis (into acetonitrile for HPLC analysis or hexane for GC...SPME. Analysis by HPLC with EPA 8310 with fluorescent detection. a) surface water quality criteria (NRWQC) are given for comparison to detection... analysis ) or hexane (for PCB analysis ) was added to the inserts. The vials were then analyzed directly by HPLC (PAHs) or GC-ECD (PCBs). Fiber achieved

Image Analysis, Microscopic, and Spectrochemical Study of the PVC Dry Blending Process,

DTIC Science & Technology

The dry blending process used in the production of electrical grade pvc formulations has been studies using a combination of image analysis , microscopic...by image analysis techniques. Optical and scanning electron microscopy were used to assess morphological differences. Spectrochemical techniques were used to indicate chemical changes.

75 FR 72727 - Addition of National Toxicology Program Carcinogens; Community Right-to-Know Toxic Chemical...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-26

... is (202) 566-1752. FOR FURTHER INFORMATION CONTACT: Daniel R. Bushman, Environmental Analysis Division, Office of Information Analysis and Access (2842T), Environmental Protection Agency, 1200... Environmental Information, Office of Information Analysis and Access. August 12, 2010. 4. NTP, 2005. National...

Direct analysis in real time-Mass spectrometry (DART-MS) in forensic and security applications.

PubMed

Pavlovich, Matthew J; Musselman, Brian; Hall, Adam B

2018-03-01

Over the last decade, direct analysis in real time (DART) has emerged as a viable method for fast, easy, and reliable "ambient ionization" for forensic analysis. The ability of DART to generate ions from chemicals that might be present at the scene of a criminal activity, whether they are in the gas, liquid, or solid phase, with limited sample preparation has made the technology a useful analytical tool in numerous forensic applications. This review paper summarizes many of those applications, ranging from the analysis of trace evidence to security applications, with a focus on providing the forensic scientist with a resource for developing their own applications. The most common uses for DART in forensics are in studying seized drugs, drugs of abuse and their metabolites, bulk and detonated explosives, toxic chemicals, chemical warfare agents, inks and dyes, and commercial plant and animal products that have been adulterated for economic gain. This review is meant to complement recent reviews that have described the fundamentals of the ionization mechanism and the general use of DART. We describe a wide range of forensic applications beyond the field of analyzing drugs of abuse, which dominates the literature, including common experimental and data analysis methods. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 37:171-187, 2018. © 2016 Wiley Periodicals, Inc.

Poor-quality antimalarial drugs in southeast Asia and sub-Saharan Africa.

PubMed

Nayyar, Gaurvika M L; Breman, Joel G; Newton, Paul N; Herrington, James

2012-06-01

Poor-quality antimalarial drugs lead to drug resistance and inadequate treatment, which pose an urgent threat to vulnerable populations and jeopardise progress and investments in combating malaria. Emergence of artemisinin resistance or tolerance in Plasmodium falciparum on the Thailand-Cambodia border makes protection of the effectiveness of the drug supply imperative. We reviewed published and unpublished studies reporting chemical analyses and assessments of packaging of antimalarial drugs. Of 1437 samples of drugs in five classes from seven countries in southeast Asia, 497 (35%) failed chemical analysis, 423 (46%) of 919 failed packaging analysis, and 450 (36%) of 1260 were classified as falsified. In 21 surveys of drugs from six classes from 21 countries in sub-Saharan Africa, 796 (35%) of 2297 failed chemical analysis, 28 (36%) of 77 failed packaging analysis, and 79 (20%) of 389 were classified as falsified. Data were insufficient to identify the frequency of substandard (products resulting from poor manufacturing) antimalarial drugs, and packaging analysis data were scarce. Concurrent interventions and a multifaceted approach are needed to define and eliminate criminal production, distribution, and poor manufacturing of antimalarial drugs. Empowering of national medicine regulatory authorities to protect the global drug supply is more important than ever. Copyright © 2012 Elsevier Ltd. All rights reserved.

Characterization and discrimination of raw and vinegar-baked Bupleuri radix based on UHPLC-Q-TOF-MS coupled with multivariate statistical analysis.

PubMed

Lei, Tianli; Chen, Shifeng; Wang, Kai; Zhang, Dandan; Dong, Lin; Lv, Chongning; Wang, Jing; Lu, Jincai

2018-02-01

Bupleuri Radix is a commonly used herb in clinic, and raw and vinegar-baked Bupleuri Radix are both documented in the Pharmacopoeia of People's Republic of China. According to the theories of traditional Chinese medicine, Bupleuri Radix possesses different therapeutic effects before and after processing. However, the chemical mechanism of this processing is still unknown. In this study, ultra-high-performance liquid chromatography with quadruple time-of-flight mass spectrometry coupled with multivariate statistical analysis including principal component analysis and orthogonal partial least square-discriminant analysis was developed to holistically compare the difference between raw and vinegar-baked Bupleuri Radix for the first time. As a result, 50 peaks in raw and processed Bupleuri Radix were detected, respectively, and a total of 49 peak chemical compounds were identified. Saikosaponin a, saikosaponin d, saikosaponin b 3 , saikosaponin e, saikosaponin c, saikosaponin b 2 , saikosaponin b 1 , 4''-O-acetyl-saikosaponin d, hyperoside and 3',4'-dimethoxy quercetin were explored as potential markers of raw and vinegar-baked Bupleuri Radix. This study has been successfully applied for global analysis of raw and vinegar-processed samples. Furthermore, the underlying hepatoprotective mechanism of Bupleuri Radix was predicted, which was related to the changes of chemical profiling. Copyright © 2017 John Wiley & Sons, Ltd.

An improved synthesis, spectroscopic (FT-IR, NMR) study and DFT computational analysis (IR, NMR, UV-Vis, MEP diagrams, NBO, NLO, FMO) of the 1,5-methanoazocino[4,3-b]indole core structure

NASA Astrophysics Data System (ADS)

Uludağ, Nesimi; Serdaroğlu, Goncagül

2018-03-01

This study examines the synthesis of azocino[4,3-b]indole structure, which constitutes the tetracyclic framework of uleine, dasycarpidoneand tubifolidineas well as ABDE substructure of the strychnosalkaloid family. It has been synthesized by Fischer indolization of 2 and through the cylization of 4 by 2,3-dichlor-5-6-dicyanobenzoquinone (DDQ). 1H and 1C NMR chemical shifts have been predicted with GIAO approach and the calculated chemical shifts show very good agreement with observed shifts. FT-IR spectroscopy is important for the analysis of functional groups of synthesized compounds and we also supported FT-IR vibrational analysis with computational IR analysis. The vibrational spectral analysis was performed at B3LYP level of the theory in both the gas and the water phases and it was compared with the observed IR values for the important functional groups. The DFT calculations have been conducted to determine the most stable structure of the 1,2,3,4,5,6,7-Hexahydro-1,5-methanoazocino [4,3-b] indole (5). The Frontier Molecular Orbital Analysis, quantum chemical parameters, physicochemical properties have been predicted by using the same theory of level in both gas phase and the water phase, at 631 + g** and 6311++g** basis sets. TD- DFT calculations have been performed to predict the UV- Vis spectral analysis for this synthesized molecule. The Natural Bond Orbital (NBO) analysis have been performed at B3LYP level of theory to elucidate the intra-molecular interactions such as electron delocalization and conjugative interactions. NLO calculations were conducted to obtain the electric dipole moment and polarizability of the title compound.

Automated, Ultra-Sterile Solid Sample Handling and Analysis on a Chip

NASA Technical Reports Server (NTRS)

Mora, Maria F.; Stockton, Amanda M.; Willis, Peter A.

2013-01-01

There are no existing ultra-sterile lab-on-a-chip systems that can accept solid samples and perform complete chemical analyses without human intervention. The proposed solution is to demonstrate completely automated lab-on-a-chip manipulation of powdered solid samples, followed by on-chip liquid extraction and chemical analysis. This technology utilizes a newly invented glass micro-device for solid manipulation, which mates with existing lab-on-a-chip instrumentation. Devices are fabricated in a Class 10 cleanroom at the JPL MicroDevices Lab, and are plasma-cleaned before and after assembly. Solid samples enter the device through a drilled hole in the top. Existing micro-pumping technology is used to transfer milligrams of powdered sample into an extraction chamber where it is mixed with liquids to extract organic material. Subsequent chemical analysis is performed using portable microchip capillary electrophoresis systems (CE). These instruments have been used for ultra-highly sensitive (parts-per-trillion, pptr) analysis of organic compounds including amines, amino acids, aldehydes, ketones, carboxylic acids, and thiols. Fully autonomous amino acid analyses in liquids were demonstrated; however, to date there have been no reports of completely automated analysis of solid samples on chip. This approach utilizes an existing portable instrument that houses optics, high-voltage power supplies, and solenoids for fully autonomous microfluidic sample processing and CE analysis with laser-induced fluorescence (LIF) detection. Furthermore, the entire system can be sterilized and placed in a cleanroom environment for analyzing samples returned from extraterrestrial targets, if desired. This is an entirely new capability never demonstrated before. The ability to manipulate solid samples, coupled with lab-on-a-chip analysis technology, will enable ultraclean and ultrasensitive end-to-end analysis of samples that is orders of magnitude more sensitive than the ppb goal given in the Science Instruments.

LSENS, The NASA Lewis Kinetics and Sensitivity Analysis Code

NASA Technical Reports Server (NTRS)

Radhakrishnan, K.

2000-01-01

A general chemical kinetics and sensitivity analysis code for complex, homogeneous, gas-phase reactions is described. The main features of the code, LSENS (the NASA Lewis kinetics and sensitivity analysis code), are its flexibility, efficiency and convenience in treating many different chemical reaction models. The models include: static system; steady, one-dimensional, inviscid flow; incident-shock initiated reaction in a shock tube; and a perfectly stirred reactor. In addition, equilibrium computations can be performed for several assigned states. An implicit numerical integration method (LSODE, the Livermore Solver for Ordinary Differential Equations), which works efficiently for the extremes of very fast and very slow reactions, is used to solve the "stiff" ordinary differential equation systems that arise in chemical kinetics. For static reactions, the code uses the decoupled direct method to calculate sensitivity coefficients of the dependent variables and their temporal derivatives with respect to the initial values of dependent variables and/or the rate coefficient parameters. Solution methods for the equilibrium and post-shock conditions and for perfectly stirred reactor problems are either adapted from or based on the procedures built into the NASA code CEA (Chemical Equilibrium and Applications).

Yeast microbiota associated with spontaneous sourdough fermentations in the production of traditional wheat sourdough breads of the Abruzzo region (Italy).

PubMed

Valmorri, Sara; Tofalo, Rosanna; Settanni, Luca; Corsetti, Aldo; Suzzi, Giovanna

2010-02-01

The aims of this study were to describe the yeast community of 20 sourdoughs collected from central Italy and to characterize the sourdoughs based on chemical properties. A polyphasic approach consisting of traditional culture-based tests (spore-forming and physiological tests) and molecular techniques (PCR-RFLP, RAPD-PCR, PCR-DGGE) and chemical analysis (total acidity, acids, and sugar contents), was utilized to describe the yeast population and to investigate the chemical composition of the doughs. PCR-RFLP analysis identified 85% of the isolates as Saccharomyces cerevisiae, with the other dominant species being Candida milleri (11%), Candida krusei (2.5%), and Torulaspora delbrueckii (1%). RAPD-PCR analysis, performed with primers M13 and LA1, highlighted intraspecific polymorphism among the S. cerevisiae strains. The diversity of the sourdoughs from the Abruzzo region is reflected in the chemical composition, yeast species, and strain polymorphism. Our approach using a combination of phenotypic and genotypic methods identified the yeast species in the 20 sourdough samples and provided a complete overview of the yeast populations found in sourdoughs from the Abruzzo region.

Chemical purity using quantitative 1H-nuclear magnetic resonance: a hierarchical Bayesian approach for traceable calibrations

NASA Astrophysics Data System (ADS)

Toman, Blaza; Nelson, Michael A.; Lippa, Katrice A.

2016-10-01

Chemical purity assessment using quantitative 1H-nuclear magnetic resonance spectroscopy is a method based on ratio references of mass and signal intensity of the analyte species to that of chemical standards of known purity. As such, it is an example of a calculation using a known measurement equation with multiple inputs. Though multiple samples are often analyzed during purity evaluations in order to assess measurement repeatability, the uncertainty evaluation must also account for contributions from inputs to the measurement equation. Furthermore, there may be other uncertainty components inherent in the experimental design, such as independent implementation of multiple calibration standards. As such, the uncertainty evaluation is not purely bottom up (based on the measurement equation) or top down (based on the experimental design), but inherently contains elements of both. This hybrid form of uncertainty analysis is readily implemented with Bayesian statistical analysis. In this article we describe this type of analysis in detail and illustrate it using data from an evaluation of chemical purity and its uncertainty for a folic acid material.

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.

Chemical elemental analysis of single acoustic-levitated water droplets by laser-induced breakdown spectroscopy.

PubMed

Contreras, Victor; Valencia, Ricardo; Peralta, Jairo; Sobral, H; Meneses-Nava, M A; Martinez, Horacio

2018-05-15

Laser-induced breakdown spectroscopy is presented for trace element detection of liquid samples by analyzing a single droplet levitated by ultrasonic waves. A single liquid droplet is placed in the node of a standing acoustic wave produced by a uniaxial levitator for further chemical analysis. The acoustic levitator consists of a commercial Langevin-type transducer, attached to a concave mechanical amplifier, and a concave reflector. A micro-syringe was used to manually place individual liquid droplet samples in the acoustic levitation system. For chemical analysis, a laser-induced plasma is produced by focusing a single laser pulse on the levitated water droplet after it partially dries. The performance of the acoustic levitator on micron-sized droplets is discussed, and the detection of Ba, Cd, Hg, and Pb at parts per million (milligrams/liter) and sub-parts per million levels is reported. The process, starting from placing the sample in the acoustic levitator and ending on the chemical identification of the traces, takes a few minutes. The approach is particularly interesting in applications demanding limited volumes of liquid samples and relative simple and inexpensive techniques.

Chemical analysis of Panax quinquefolius (North American ginseng): A review.

PubMed

Wang, Yaping; Choi, Hyung-Kyoon; Brinckmann, Josef A; Jiang, Xue; Huang, Linfang

2015-12-24

Panax quinquefolius (PQ) is one of the best-selling natural health products due to its proposed beneficial anti-aging, anti-cancer, anti-stress, anti-fatigue, and anxiolytic effects. In recent years, the quality of PQ has received considerable attention. Sensitive and accurate methods for qualitative and quantitative analyses of chemical constituents are necessary for the comprehensive quality control to ensure the safety and efficacy of PQ. This article reviews recent progress in the chemical analysis of PQ and its preparations. Numerous analytical techniques, including spectroscopy, thin-layer chromatography (TLC), gas chromatography (GC), high-performance liquid chromatography (HPLC), liquid chromatography/mass spectrometry (LC/MS), high-speed centrifugal partition chromatography (HSCPC), high-performance counter-current chromatography (HPCCC), nuclear magnetic resonance spectroscopy (NMR), and immunoassay, are described. Among these techniques, HPLC coupled with mass spectrometry (MS) is the most promising method for quality control. The challenges encountered in the chemical analysis of PQ are also briefly discussed, and the remaining questions regarding the quality control of PQ that require further investigation are highlighted. Copyright © 2015 Elsevier B.V. All rights reserved.

Chemical Abundance Analysis of Moving Group W11450 (Latham 1)

NASA Astrophysics Data System (ADS)

O'Connell, Julia E.; Martens, Kylee; Frinchaboy, Peter M.

2016-12-01

We present elemental abundances for all seven stars in Moving Group W11450 (Latham 1) to determine if they may be chemically related. These stars appear to be both spatially and kinematically related, but no spectroscopic abundance analysis exists in literature. Abundances for eight elements were derived via equivalent width analyses of high-resolution (R ˜ 60,000), high-signal-to-noise ratio (< {{S}}/{{N}}> ˜ 100) spectra obtained with the Otto Struve 2.1 m telescope and the Sandiford Echelle Spectrograph at McDonald Observatory. The large star-to-star scatter in metallicity, -0.55 ≤ [Fe/H] ≤slant 0.06 dex (σ = 0.25), implies these stars were not produced from the same chemically homogeneous molecular cloud, and are therefore not part of a remnant or open cluster as previously proposed. Prior to this analysis, it was suggested that two stars in the group, W11449 and W11450, are possible wide binaries. The candidate wide binary pair show similar chemical abundance patterns with not only iron but with other elements analyzed in this study, suggesting the proposed connection between these two stars may be real.

Utilization of Lesson Analysis as Teacher Self Reflection to Improve the Lesson Design on Chemical Equation Topic

NASA Astrophysics Data System (ADS)

Edyani, E. A.; Supriatna, A.; Kurnia; Komalasari, L.

2017-02-01

The research is aimed to investigate how lesson analysis as teacher’s self-reflection changes the teacher’s lesson design on chemical equation topic. Lesson Analysis has been used as part of teacher training programs to improve teacher’s ability in analyzing their own lesson. The method used in this research is a qualitative method. The research starts from build lesson design, implementation lesson design to senior high school student, utilize lesson analysis to get information about the lesson, and revise lesson design. The revised lesson design from the first implementation applied to the second implementation, resulting in better design. This research use lesson analysis Hendayana&Hidayat framework. Video tapped and transcript are employed on each lesson. After first implementation, lesson analysis result shows that teacher-centered still dominating the learning because students are less active in discussion, so the part of lesson design must be revised. After second implementation, lesson analysis result shows that the learning already student-centered. Students are very active in discussion. But some part of learning design still must be revised. In general, lesson analysis was effective for teacher to reflect the lessons. Teacher can utilize lesson analysis any time to improve the next lesson design.

Boosting Sensitivity in Liquid Chromatography–Fourier Transform Ion Cyclotron Resonance–Tandem Mass Spectrometry for Product Ion Analysis of Monoterpene Indole Alkaloids

PubMed Central

Nakabayashi, Ryo; Tsugawa, Hiroshi; Kitajima, Mariko; Takayama, Hiromitsu; Saito, Kazuki

2015-01-01

In metabolomics, the analysis of product ions in tandem mass spectrometry (MS/MS) is noteworthy to chemically assign structural information. However, the development of relevant analytical methods are less advanced. Here, we developed a method to boost sensitivity in liquid chromatography–Fourier transform ion cyclotron resonance–tandem mass spectrometry analysis (MS/MS boost analysis). To verify the MS/MS boost analysis, both quercetin and uniformly labeled 13C quercetin were analyzed, revealing that the origin of the product ions is not the instrument, but the analyzed compounds resulting in sensitive product ions. Next, we applied this method to the analysis of monoterpene indole alkaloids (MIAs). The comparative analyses of MIAs having indole basic skeleton (ajmalicine, catharanthine, hirsuteine, and hirsutine) and oxindole skeleton (formosanine, isoformosanine, pteropodine, isopteropodine, rhynchophylline, isorhynchophylline, and mitraphylline) identified 86 and 73 common monoisotopic ions, respectively. The comparative analyses of the three pairs of stereoisomers showed more than 170 common monoisotopic ions in each pair. This method was also applied to the targeted analysis of MIAs in Catharanthus roseus and Uncaria rhynchophylla to profile indole and oxindole compounds using the product ions. This analysis is suitable for chemically assigning features of the metabolite groups, which contributes to targeted metabolome analysis. PMID:26734034

76 FR 28336 - Domestic Licensing of Source Material-Amendments/Integrated Safety Analysis

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-17

... considered. The HF gas (and uranyl fluoride) is quickly produced from the chemical reaction that occurs when... worker's death was the inhalation of HF gas, which was produced from the chemical reaction of UF6 and..., would address both the radiological and chemical hazards from licensed material and hazardous chemicals...

Film processing investigation. [improved chemical mixing system

NASA Technical Reports Server (NTRS)

Kelly, J. L.

1972-01-01

The present operational chemical mixing system for the Photographic Technology Division is evaluated, and the limitations are defined in terms of meeting the present and programmed chemical supply and delivery requirements. A major redesign of the entire chemical mixing, storage, analysis, and supply system is recommended. Other requirements for immediate and future implementations are presented.

Identifying developmental toxicity pathways for a subset of ToxCast chemicals using human embryonic stem cells and metabolomics

EPA Science Inventory

Metabolomics analysis was performed on the supernatant of human embryonic stem (hES) cell cultures exposed to a blinded subset of 11 chemicals selected from the chemical library of EPA's ToxCast™ chemical screening and prioritization research project. Metabolites from hES cultur...

Dynamic Processes of Conceptual Change: Analysis of Constructing Mental Models of Chemical Equilibrium.

ERIC Educational Resources Information Center

Chiu, Mei-Hung; Chou, Chin-Cheng; Liu, Chia-Ju

2002-01-01

Investigates students' mental models of chemical equilibrium using dynamic science assessments. Reports that students at various levels have misconceptions about chemical equilibrium. Involves 10th grade students (n=30) in the study doing a series of hands-on chemical experiments. Focuses on the process of constructing mental models, dynamic…

Assessment of chemical exchange in tryptophan-albumin solution through (19)F multicomponent transverse relaxation dispersion analysis.

PubMed

Lin, Ping-Chang

2015-06-01

A number of NMR methods possess the capability of probing chemical exchange dynamics in solution. However, certain drawbacks limit the applications of these NMR approaches, particularly, to a complex system. Here, we propose a procedure that integrates the regularized nonnegative least squares (NNLS) analysis of multiexponential T2 relaxation into Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments to probe chemical exchange in a multicompartmental system. The proposed procedure was validated through analysis of (19)F T2 relaxation data of 6-fluoro-DL-tryptophan in a two-compartment solution with and without bovine serum albumin. Given the regularized NNLS analysis of a T2 relaxation curve acquired, for example, at the CPMG frequency υ CPMG  = 125, the nature of two distinct peaks in the associated T2 distribution spectrum indicated 6-fluoro-DL-tryptophan either retaining the free state, with geometric mean */multiplicative standard deviation (MSD) = 1851.2 ms */1.51, or undergoing free/albumin-bound interconversion, with geometric mean */MSD = 236.8 ms */1.54, in the two-compartment system. Quantities of the individual tryptophan species were accurately reflected by the associated T2 peak areas, with an interconversion state-to-free state ratio of 0.45 ± 0.11. Furthermore, the CPMG relaxation dispersion analysis estimated the exchange rate between the free and albumin-bound states in this fluorinated tryptophan analog and the corresponding dissociation constant of the fluorinated tryptophan-albumin complex in the chemical-exchanging, two-compartment system.

Classification and statistical analysis of mine spoils chemical composition from Oliete basin (Teruel, NE Spain)

NASA Astrophysics Data System (ADS)

Meseguer, S.; Sanfeliu, T.; Jordán, M. M.

2009-02-01

The Oliete basin (Early Cretaceous, NE Teruel, Spain) is one of the most important areas for the supply of mine spoils used as ball clays for the production of white and red stoneware in the Spanish ceramic industry of wall and floor tiles. This study corresponds to the second part of the paper published recently by Meseguer et al. (Environ Geol 2008) about the use of mine spoils from Teruel coal mining district. The present study shows a statistical data analysis from chemical data (major, minor and trace elements). The performed statistical analysis of chemical data included descriptive statistics and cluster analysis (with ANOVA and Scheffé methods). The cluster analysis of chemical data provided three main groups: C3 with the highest mean SiO2 content (66%) and lowest mean Al2O3 content (20%); C2 with lower SiO2 content (48%) and higher mean Al2O3 content (28%); and C1 with medium values for the SiO2 and Al2O3 mean content. The main applications of these materials are refractory, white and red ceramics, stoneware, heavy ceramics (including red earthenware, bricks and roof tiles), and components of white Portland cement and aluminous cement. Clays from group 2 are used in refractories (with higher kaolinite content, and constrictions to CaO + MgO and K2O + Na2O contents). All materials can be used in fine ceramics (white or red, according to the Fe2O3 + TiO2 content).

Fast classification and compositional analysis of cornstover fractions using Fourier transform near-infrared techniques.

PubMed

Philip Ye, X; Liu, Lu; Hayes, Douglas; Womac, Alvin; Hong, Kunlun; Sokhansanj, Shahab

2008-10-01

The objectives of this research were to determine the variation of chemical composition across botanical fractions of cornstover, and to probe the potential of Fourier transform near-infrared (FT-NIR) techniques in qualitatively classifying separated cornstover fractions and in quantitatively analyzing chemical compositions of cornstover by developing calibration models to predict chemical compositions of cornstover based on FT-NIR spectra. Large variations of cornstover chemical composition for wide calibration ranges, which is required by a reliable calibration model, were achieved by manually separating the cornstover samples into six botanical fractions, and their chemical compositions were determined by conventional wet chemical analyses, which proved that chemical composition varies significantly among different botanical fractions of cornstover. Different botanic fractions, having total saccharide content in descending order, are husk, sheath, pith, rind, leaf, and node. Based on FT-NIR spectra acquired on the biomass, classification by Soft Independent Modeling of Class Analogy (SIMCA) was employed to conduct qualitative classification of cornstover fractions, and partial least square (PLS) regression was used for quantitative chemical composition analysis. SIMCA was successfully demonstrated in classifying botanical fractions of cornstover. The developed PLS model yielded root mean square error of prediction (RMSEP %w/w) of 0.92, 1.03, 0.17, 0.27, 0.21, 1.12, and 0.57 for glucan, xylan, galactan, arabinan, mannan, lignin, and ash, respectively. The results showed the potential of FT-NIR techniques in combination with multivariate analysis to be utilized by biomass feedstock suppliers, bioethanol manufacturers, and bio-power producers in order to better manage bioenergy feedstocks and enhance bioconversion.

40 CFR 766.1 - Scope and purpose.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ascertain whether certain specified chemical substances may be contaminated with halogenated dibenzodioxins... TSCA, 15 U.S.C. 2607. (b) Section 766.35(b) requires manufacturers and processors of chemical... chemical substances for concentrations of HDDs/HDFs, applicable protocols, and the results of the analysis...

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...

Accuracy and precision of protein-ligand interaction kinetics determined from chemical shift titrations.

PubMed

Markin, Craig J; Spyracopoulos, Leo

2012-12-01

NMR-monitored chemical shift titrations for the study of weak protein-ligand interactions represent a rich source of information regarding thermodynamic parameters such as dissociation constants (K ( D )) in the micro- to millimolar range, populations for the free and ligand-bound states, and the kinetics of interconversion between states, which are typically within the fast exchange regime on the NMR timescale. We recently developed two chemical shift titration methods wherein co-variation of the total protein and ligand concentrations gives increased precision for the K ( D ) value of a 1:1 protein-ligand interaction (Markin and Spyracopoulos in J Biomol NMR 53: 125-138, 2012). In this study, we demonstrate that classical line shape analysis applied to a single set of (1)H-(15)N 2D HSQC NMR spectra acquired using precise protein-ligand chemical shift titration methods we developed, produces accurate and precise kinetic parameters such as the off-rate (k ( off )). For experimentally determined kinetics in the fast exchange regime on the NMR timescale, k ( off ) ~ 3,000 s(-1) in this work, the accuracy of classical line shape analysis was determined to be better than 5 % by conducting quantum mechanical NMR simulations of the chemical shift titration methods with the magnetic resonance toolkit GAMMA. Using Monte Carlo simulations, the experimental precision for k ( off ) from line shape analysis of NMR spectra was determined to be 13 %, in agreement with the theoretical precision of 12 % from line shape analysis of the GAMMA simulations in the presence of noise and protein concentration errors. In addition, GAMMA simulations were employed to demonstrate that line shape analysis has the potential to provide reasonably accurate and precise k ( off ) values over a wide range, from 100 to 15,000 s(-1). The validity of line shape analysis for k ( off ) values approaching intermediate exchange (~100 s(-1)), may be facilitated by more accurate K ( D ) measurements from NMR-monitored chemical shift titrations, for which the dependence of K ( D ) on the chemical shift difference (Δω) between free and bound states is extrapolated to Δω = 0. The demonstrated accuracy and precision for k ( off ) will be valuable for the interpretation of biological kinetics in weakly interacting protein-protein networks, where a small change in the magnitude of the underlying kinetics of a given pathway may lead to large changes in the associated downstream signaling cascade.

Recent advancements in chemical luminescence-based lab-on-chip and microfluidic platforms for bioanalysis.

PubMed

Mirasoli, Mara; Guardigli, Massimo; Michelini, Elisa; Roda, Aldo

2014-01-01

Miniaturization of analytical procedures through microchips, lab-on-a-chip or micro total analysis systems is one of the most recent trends in chemical and biological analysis. These systems are designed to perform all the steps in an analytical procedure, with the advantages of low sample and reagent consumption, fast analysis, reduced costs, possibility of extra-laboratory application. A range of detection technologies have been employed in miniaturized analytical systems, but most applications relied on fluorescence and electrochemical detection. Chemical luminescence (which includes chemiluminescence, bioluminescence, and electrogenerated chemiluminescence) represents an alternative detection principle that offered comparable (or better) analytical performance and easier implementation in miniaturized analytical devices. Nevertheless, chemical luminescence-based ones represents only a small fraction of the microfluidic devices reported in the literature, and until now no review has been focused on these devices. Here we review the most relevant applications (since 2009) of miniaturized analytical devices based on chemical luminescence detection. After a brief overview of the main chemical luminescence systems and of the recent technological advancements regarding their implementation in miniaturized analytical devices, analytical applications are reviewed according to the nature of the device (microfluidic chips, microchip electrophoresis, lateral flow- and paper-based devices) and the type of application (micro-flow injection assays, enzyme assays, immunoassays, gene probe hybridization assays, cell assays, whole-cell biosensors). Copyright © 2013 Elsevier B.V. All rights reserved.

Comparison of chemical-activated luciferase gene expression bioassay and gas chromatography for PCB determination in human serum and follicular fluid.

PubMed Central

Pauwels, A; Cenijn, P H; Schepens, P J; Brouwer, A

2000-01-01

We assessed exposure to dioxin-like compounds using chemical and bioassay analysis in different matrices in a female population. A total of 106 serum and 9 follicular fluid samples were collected from infertile women attending Centers for Reproductive Medicine in Belgium from 1996 to 1998. Major polychlorinated biphenyl (PCB) congeners were quantified by chemical analysis using gas chromatography with electron-capture detection, and the chemical-activated luciferase gene expression (CALUX) bioassay was used to determine the total dioxin-like toxic equivalence (TEQ) of mixtures of polyhalogenated aromatic hydrocarbons present in body fluids, such as serum and follicular fluid. To the best of our knowledge, this is the first investigation to determine TEQ values by the CALUX bioassay in follicular fluid. The TEQ levels in both matrices are well correlated (r = 0.83, p = 0.02). As the chemical and bioassay analysis executed in this study do not cover the same span of polyhalogenated aromatic hydrocarbons, we did not expect totally correlated results. Moreover, the sample workup and quantification of the analytes differed completely. Nonetheless, the TEQ values in human extracts correlated well with the sum of four major PCB congeners chemically determined in both serum and follicular fluid. These results indicate that the CALUX bioassay may serve as a simple, relatively inexpensive prescreening tool for exposure assessment in epidemiologic surveys. Images Figure 1 Figure 2 PMID:10856030

Bursting synchronization dynamics of pancreatic β-cells with electrical and chemical coupling.

PubMed

Meng, Pan; Wang, Qingyun; Lu, Qishao

2013-06-01

Based on bifurcation analysis, the synchronization behaviors of two identical pancreatic β-cells connected by electrical and chemical coupling are investigated, respectively. Various firing patterns are produced in coupled cells when a single cell exhibits tonic spiking or square-wave bursting individually, irrespectively of what the cells are connected by electrical or chemical coupling. On the one hand, cells can burst synchronously for both weak electrical and chemical coupling when an isolated cell exhibits tonic spiking itself. In particular, for electrically coupled cells, under the variation of the coupling strength there exist complex transition processes of synchronous firing patterns such as "fold/limit cycle" type of bursting, then anti-phase continuous spiking, followed by the "fold/torus" type of bursting, and finally in-phase tonic spiking. On the other hand, it is shown that when the individual cell exhibits square-wave bursting, suitable coupling strength can make the electrically coupled system generate "fold/Hopf" bursting via "fold/fold" hysteresis loop; whereas, the chemically coupled cells generate "fold/subHopf" bursting. Especially, chemically coupled bursters can exhibit inverse period-adding bursting sequence. Fast-slow dynamics analysis is applied to explore the generation mechanism of these bursting oscillations. The above analysis of bursting types and the transition may provide us with better insight into understanding the role of coupling in the dynamic behaviors of pancreatic β-cells.

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

Green, D.W.; Boparai, A.S.; Bowers, D.L.

The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for fiscal year (FY) 1995 (October 1994 through September 1995). This annual report is the twelfth for the ACL and describes work on 54 continuing and new projects and contributions of the ACL staff to various programs at ANL. The ACL has four technical groups -- Chemical Analysis, Instrumental Analysis, Organic Analysis, and Environmental Analysis.

Teardown analysis for detecting shelf-life degradation

NASA Technical Reports Server (NTRS)

Eckstein, A. S.

1971-01-01

Analysis is guideline in examining component materials, analytically determining physical properties and chemical compositions, and developing control data necessary for ascertaining effects of environments and their influence on deterioration and degradation mechanisms.

DNA-encoded chemistry: enabling the deeper sampling of chemical space.

PubMed

Goodnow, Robert A; Dumelin, Christoph E; Keefe, Anthony D

2017-02-01

DNA-encoded chemical library technologies are increasingly being adopted in drug discovery for hit and lead generation. DNA-encoded chemistry enables the exploration of chemical spaces four to five orders of magnitude more deeply than is achievable by traditional high-throughput screening methods. Operation of this technology requires developing a range of capabilities including aqueous synthetic chemistry, building block acquisition, oligonucleotide conjugation, large-scale molecular biological transformations, selection methodologies, PCR, sequencing, sequence data analysis and the analysis of large chemistry spaces. This Review provides an overview of the development and applications of DNA-encoded chemistry, highlighting the challenges and future directions for the use of this technology.

Contaminants of emerging concern in the lower Stillaguamish River Basin, Washington, 2008-11

USGS Publications Warehouse

Wagner, Richard J.; Moran, Patrick W.; Zaugg, Steven D.; Sevigny, Jennifer M.; Pope, Judy M.

2014-01-01

A series of discrete water-quality samples were collected in the lower Stillaguamish River Basin near the city of Arlington, Washington, through a partnership with the Stillaguamish Tribe of Indians. These samples included surface waters of the Stillaguamish River, adjacent tributary streams, and paired inflow and outflow sampling at three wastewater treatment plants in the lower river basin. Chemical analysis of these samples focused on chemicals of emerging concern, including wastewater compounds, human-health pharmaceuticals, steroidal hormones, and halogenated organic compounds on solids and sediment. This report presents the methods used and data results from the chemical analysis of these samples

Uses of NHANES biomarker data for chemical risk ...

EPA Pesticide Factsheets

Background. Each year, the US NHANES measures hundreds of chemical biomarkers in samples from thousands of study participants. These biomarker measurements are meant to track trends and identify subsets of the US population with elevated exposures. There is now interest in further utilizing the NHANES data to inform chemical risk assessments. Objectives. This article highlights: 1) the extent to which NHANES chemical biomarker data have been evaluated, 2) groups of chemicals that have been studied, 3) data analysis approaches, and 4) opportunities for using these data to inform chemical risk assessments.Methods. A literature search (1999-2013) was performed to identify publications in which NHANES data were reported. Manual curation identified only the subset of publications that clearly utilized chemical biomarker data. This subset was evaluated for chemical groupings, data analysis approaches, and overall trends.Results. A small percentage of yearly NHANES-related publications reported on chemical biomarkers (8% yearly average). Of eleven chemical groups, metals/metalloids were most frequently evaluated (49%), followed by pesticides (9%) and environmental phenols (7%). Studies of multiple chemical groups were also common (8%). Publications linking chemical biomarkers to health metrics have increased dramatically in recent years. New studies are addressing challenges related to NHANES data interpretation in health risk contexts.Conclusions. This articl

Public perception and attitude towards chemical industry park in Dalian, Bohai Rim.

PubMed

He, Guizhen; Chen, Chunci; Zhang, Lei; Lu, Yonglong

2018-04-01

Recent decade has witnessed accelerating expansion of chemical industry and increasing conflicts between the local citizens, governmental authorities and project developers, especially in some coastal and port cities in China. Development and transformation of chemical industrial parks has been adopted as a national initiative recently. However, there is a paucity of research examining public perspectives on chemical industrial parks and their risks. Aiming to understand public perception, attitude, and response and the factors underlying the support/acceptance of chemical industry park, this paper investigated 418 residents neighboring to two chemical industrial parks, Dalian in Bohai Rim through face-to-face questionnaire survey. The results showed the knowledge of the respondents on the chemical industrial parks development was very limited. The respondents had complex perceptions on the environmental impacts, risks control, social-economic benefits, and problem awareness. The current levels of information disclosure and public participation were very low. The central governmental official (44.3%) was the most trustworthy group by the respondents. Only 5.5% and 23.2% of the respondents supported the construction of a new CIP nearby and far away their homes, whilst 13% thought new CIP project as acceptable. The spearman correlation analysis results showed a strong NIMBY effect (Not In My Backyard). Factor analysis results demonstrated five latent factors: knowledge, benefit, information, trust, and participation. Multiple linear regression analysis indicated how socio-demographic differences and five latent factors might impact on the support/acceptance of the chemical industrial parks. Education level, trust, information, and participation were significant predictors of public support/acceptance level. This study contributes to our limited knowledge and understanding of public sentiments to the chemical industry parks in China. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hierarchical cluster analysis of technical replicates to identify interferents in untargeted mass spectrometry metabolomics.

PubMed

Caesar, Lindsay K; Kvalheim, Olav M; Cech, Nadja B

2018-08-27

Mass spectral data sets often contain experimental artefacts, and data filtering prior to statistical analysis is crucial to extract reliable information. This is particularly true in untargeted metabolomics analyses, where the analyte(s) of interest are not known a priori. It is often assumed that chemical interferents (i.e. solvent contaminants such as plasticizers) are consistent across samples, and can be removed by background subtraction from blank injections. On the contrary, it is shown here that chemical contaminants may vary in abundance across each injection, potentially leading to their misidentification as relevant sample components. With this metabolomics study, we demonstrate the effectiveness of hierarchical cluster analysis (HCA) of replicate injections (technical replicates) as a methodology to identify chemical interferents and reduce their contaminating contribution to metabolomics models. Pools of metabolites with varying complexity were prepared from the botanical Angelica keiskei Koidzumi and spiked with known metabolites. Each set of pools was analyzed in triplicate and at multiple concentrations using ultraperformance liquid chromatography coupled to mass spectrometry (UPLC-MS). Before filtering, HCA failed to cluster replicates in the data sets. To identify contaminant peaks, we developed a filtering process that evaluated the relative peak area variance of each variable within triplicate injections. These interferent peaks were found across all samples, but did not show consistent peak area from injection to injection, even when evaluating the same chemical sample. This filtering process identified 128 ions that appear to originate from the UPLC-MS system. Data sets collected for a high number of pools with comparatively simple chemical composition were highly influenced by these chemical interferents, as were samples that were analyzed at a low concentration. When chemical interferent masses were removed, technical replicates clustered in all data sets. This work highlights the importance of technical replication in mass spectrometry-based studies, and presents a new application of HCA as a tool for evaluating the effectiveness of data filtering prior to statistical analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

Buying drugs on a Darknet market: A better deal? Studying the online illicit drug market through the analysis of digital, physical and chemical data.

PubMed

Rhumorbarbe, Damien; Staehli, Ludovic; Broséus, Julian; Rossy, Quentin; Esseiva, Pierre

2016-10-01

Darknet markets, also known as cryptomarkets, are websites located on the Darknet and designed to allow the trafficking of illicit products, mainly drugs. This study aims at presenting the added value of combining digital, chemical and physical information to reconstruct sellers' activities. In particular, this research focuses on Evolution, one of the most popular cryptomarkets active from January 2014 to March 2015. Evolution source code files were analysed using Python scripts based on regular expressions to extract information about listings (i.e., sales proposals) and sellers. The results revealed more than 48,000 listings and around 2700 vendors claiming to send illicit drug products from 70 countries. The most frequent categories of illicit drugs offered by vendors were cannabis-related products (around 25%) followed by ecstasy (MDA, MDMA) and stimulants (cocaine, speed). The cryptomarket was then especially studied from a Swiss point of view. Illicit drugs were purchased from three sellers located in Switzerland. The purchases were carried out to confront digital information (e.g., the type of drug, the purity, the shipping country and the concealment methods mentioned on listings) with the physical analysis of the shipment packaging and the chemical analysis of the received product (purity, cutting agents, chemical profile based on minor and major alkaloids, chemical class). The results show that digital information, such as concealment methods and shipping country, seems accurate. But the illicit drugs purity is found to be different from the information indicated on their respective listings. Moreover, chemical profiling highlighted links between cocaine sold online and specimens seized in Western Switzerland. This study highlights that (1) the forensic analysis of the received products allows the evaluation of the accuracy of digital data collected on the website, and (2) the information from digital and physical/chemical traces are complementary to evaluate the practices of the online selling of illicit drugs on cryptomarkets. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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

Sun, Amy Cha-Tien; Downes, Paula Sue; Heinen, Russell

Analysis of chemical supply chains is an inherently complex task, given the dependence of these supply chains on multiple infrastructure systems (e.g., the petroleum sector, transportation, etc.). This effort requires data and information at various levels of resolution, ranging from network-level distribution systems to individual chemical reactions. Sandia National Laboratories (Sandia) has integrated its existing simulation and infrastructure analysis capabilities with chemical data models to analyze the chemical supply chains of several nationally critical chemical commodities. This paper describes how Sandia models the ethylene supply chain; that is, the supply chain for the most widely used raw material for plasticsmore » production including a description of the types of data and modeling capabilities that are required to represent the ethylene supply chain. The paper concludes with a description of Sandia's use the model to project how the supply chain would be affected by and adapt to a disruptive scenario hurricane.« less

The use of computer-assisted image analysis in the evaluation of the effect of management systems on changes in the color, chemical composition and texture of m. longissimus dorsi in pigs.

PubMed

Zapotoczny, Piotr; Kozera, Wojciech; Karpiesiuk, Krzysztof; Pawłowski, Rodian

2014-08-01

The effect of management systems on selected physical properties and chemical composition of m. longissimus dorsi was studied in pigs. Muscle texture parameters were determined by computer-assisted image analysis, and the color of muscle samples was evaluated using a spectrophotometer. Highly significant correlations were observed between chemical composition and selected texture variables in the analyzed images. Chemical composition was not correlated with color or spectral distribution. Subject to the applied classification methods and groups of variables included in the classification model, the experimental groups were identified correctly in 35-95%. No significant differences in the chemical composition of m. longissimus dorsi were observed between experimental groups. Significant differences were noted in color lightness (L*) and redness (a*). Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemically bonded stationary phases that use synthetic hosts containing aromatic binding clefts: HPLC analysis of nitro-substituted polycyclic aromatic hydrocarbons.

PubMed Central

Zimmerman, S C; Saionz, K W; Zeng, Z

1993-01-01

The synthesis of hosts with improved binding affinities for nitroaromatic guests is described. Association constants for several host-guest complexes were measured in chloroform solution and ranged over three orders of magnitude. Two hosts were covalently linked to silica gel to produce chemically bonded stationary phases for HPLC. The use of these phases for HPLC analysis of nitro-substituted polycyclic aromatic hydrocarbons is discussed. PMID:8433981

Astrobiology and the Chemistry of the Early Solar System

NASA Technical Reports Server (NTRS)

Cook, Jamie Elsila

2011-01-01

The field of astrochemistry investigates the origin of the chemicals necessary for the formation of life. Astrochemists use remote observations, laboratory simulations, and analysis of extraterrestrial samples to understand the inventory of pre biotic chemicals present on the early Earth. Among the problems investigated by astrochemists is the origin of homo chirality in terrestrial life. Analysis of meteorites shows that they may have delivered an excess of L-amino acids to the Earth's surface, perhaps leading to homochirality.

Occurrence and Mineral Chemistry of High Pressure Phases, Potrillo Basalt, Southcentral New Mexico. M.S. Thesis Final Technical Report, 1 Jun. 1980 - 31 May 1982

NASA Technical Reports Server (NTRS)

Sheffield, T. M.

1982-01-01

The presence of an older plagioclase-rich basalt and a younger olivine-rich basalt were confirmed by modal and chemical analysis. Chemical analysis also confirmed the presence of flows that are tholeiitic in composition and could be remnants of an original tholeittic parent magma. Eruptions from different levels of a differentiated magma chamber are proposed to account for the two members.

Optofluidic Microsystems for Chemical and Biological Analysis

PubMed Central

Fan, Xudong; White, Ian M.

2011-01-01

Optofluidics – the synergistic integration of photonics and microfluidics – has recently emerged as a new analytical field that provides a number of unique characteristics for enhanced sensing performance and simplification of microsystems. In this review, we describe various optofluidic architectures developed in the past five years, emphasize the mechanisms by which optofluidics enhances bio/chemical analysis capabilities, including sensing and the precise control of biological micro/nanoparticles, and envision new research directions to which optofluidics leads. PMID:22059090

Conformational analysis, spectroscopic, structure-activity relations and quantum chemical simulation studies of 4-(trifluoromethyl)benzylamine

NASA Astrophysics Data System (ADS)

Arjunan, V.; Devi, L.; Mohan, S.

2018-05-01

The FT-IR and FT-Raman spectra of 4-trifluoromethylbenzylamine (TFMBA) have been recorded in the range 4000-450 and 4000-100 cm-1 respectively. The conformational analysis of the compound has been carried out to attain stable geometry of the compound. The complete vibrational assignment and analysis of the fundamental modes of the compound are carried out using the experimental FTIR and FT-Raman data and quantum chemical studies. The experimental vibrational frequencies are compared with the wavenumbers obtained theoretically from the B3LYP gradient calculations employing the standard high level 6-311++G** and cc-pVTZ basis sets for the optimised geometry of the compound. The structural parameters, thermodynamic properties and vibrational frequencies of the normal modes obtained from the B3LYP methods are in good agreement with the experimental data. The 1H (400 MHz; CDCl3) and 13C (100 MHz; CDCl3) nuclear magnetic resonance (NMR) spectra were also recorded. The electronic properties, highest occupied molecular orbital and lowest unoccupied molecular orbital energies are measured by DFT approach. The charges of the atoms by natural bond orbital (NBO) analysis are determined by B3LYP/cc-pVTZ method. The structure-chemical reactivity relations of the compound are determined through chemical potential, global hardness, global softness, electronegativity, electrophilicity and local reactivity descriptors by conceptual DFT methods.

Variations in chemical fingerprints and major flavonoid contents from the leaves of thirty‐one accessions of Hibiscus sabdariffa L.

PubMed Central

Wang, Jin; Cao, Xianshuang; Ferchaud, Vanessa; Jiang, Hao; Tang, Feng; Chin, Kit L.

2015-01-01

Abstract The leaves of Hibiscus sabdariffa L. have been used as traditional folk medicines for treating high blood pressure and fever. There are many accessions of H. sabdariffa L. throughout the world. To assess the chemical variations of 31 different accessions of H. sabdariffa L., fingerprinting analysis and quantitation of major flavonoids were performed by high‐performance liquid chromatography (HPLC). The HPLC method was validated for linearity, sensitivity, precision, repeatability and accuracy. A quadrupole‐time‐of‐flight mass spectrometry (Q‐TOF‐MS) was applied for the characterization of major compounds. A total of 9 compounds were identified, including 6 flavonoids and 3 phenolic acids. In the fingerprint analysis, similarity analysis (SA) and principal component analysis (PCA) were used to differentiate the 31 accessions of H. sabdariffa L. Based on the results of PCA and SA, the samples No. 15 and 19 appeared much different from the main group. The total content of five flavonoids varied greatly among different accessions, ranging from 3.35 to 23.30 mg/g. Rutin was found to be the dominant compound and the content of rutin could contribute to chemical variations among different accessions. This study was helpful to understand the chemical variations between different accessions of H. sabdariffa L., which could be used for quality control. © 2015 The Authors Biomedical Chromatography Published by John Wiley & Sons Ltd. PMID:26394363

Chemical and Thermal Analysis

NASA Technical Reports Server (NTRS)

Bulluck, J. W.; Rushing, R. A.; Thornton, C. P.

1996-01-01

Work has included significant research in several areas aimed at further clarification of the aging and chemical failure mechanism of thermoplastics (PVDF or Tefzel) for pipes. Among the areas investigated were the crystallinity changes associated with both the Coflon and Tefzel after various simulated environmental exposures using X-Ray diffraction analysis. We have found that significant changes in polymer crystallinity levels occur as a function of the exposures. These crystallinity changes may have important consequences on the fracture, fatigue, tensile, and chemical resistance of the materials. We have also noted changes in the molecular weight distribution of the Coflon material using a dual detector Gel Permeation Analysis. Again these changes may result in variation in the mechanical and chemical properties in the material. We conducted numerous analytical studies with methods including X-Ray Diffraction, Gel Permeation Chromatography, Fourier Transform Infrared Spectroscopy, Thermogravimetric Analysis, and Differential Scanning Calorimetry. We investigated a number of aged samples of both Tefzel and Coflon that were forwarded from MERL. Pressurized tests were performed in a modified Fluid G, which we will call G2. In this case the ethylene diamine concentration was increased to 3 percent in methanol. Coflon pipe sections and powdered Coflon were exposed in pressure cells at 1700 psi at three separate test temperatures, 70 C, 110 C, and 130 C. The primary purpose of the pressure tests in Fluid G2 was to further elucidate the aging mechanism of PVDF degradation.

Industrial applications using BASF eco-efficiency analysis: perspectives on green engineering principles.

PubMed

Shonnard, David R; Kicherer, Andreas; Saling, Peter

2003-12-01

Life without chemicals would be inconceivable, but the potential risks and impacts to the environment associated with chemical production and chemical products are viewed critically. Eco-efficiency analysis considers the economic and life cycle environmental effects of a product or process, giving these equal weighting. The major elements of the environmental assessment include primary energy use, raw materials utilization, emissions to all media, toxicity, safety risk, and land use. The relevance of each environmental category and also for the economic versus the environmental impacts is evaluated using national emissions and economic data. The eco-efficiency analysis method of BASF is briefly presented, and results from three applications to chemical processes and products are summarized. Through these applications, the eco-efficiency analyses mostly confirm the 12 Principles listed in Anastas and Zimmerman (Environ. Sci. Technol. 2003, 37(5), 94A), with the exception that, in one application, production systems based on bio-based feedstocks were not the most eco-efficient as compared to those based on fossil resources. Over 180 eco-efficiency analyses have been conducted at BASF, and their results have been used to support strategic decision-making, marketing, research and development, and communication with external parties. Eco-efficiency analysis, as one important strategy and success factor in sustainable development, will continue to be a very strong operational tool at BASF.

Systematic analysis of Ca2+ homeostasis in Saccharomyces cerevisiae based on chemical-genetic interaction profiles

PubMed Central

Ghanegolmohammadi, Farzan; Yoshida, Mitsunori; Ohnuki, Shinsuke; Sukegawa, Yuko; Okada, Hiroki; Obara, Keisuke; Kihara, Akio; Suzuki, Kuninori; Kojima, Tetsuya; Yachie, Nozomu; Hirata, Dai; Ohya, Yoshikazu

2017-01-01

We investigated the global landscape of Ca2+ homeostasis in budding yeast based on high-dimensional chemical-genetic interaction profiles. The morphological responses of 62 Ca2+-sensitive (cls) mutants were quantitatively analyzed with the image processing program CalMorph after exposure to a high concentration of Ca2+. After a generalized linear model was applied, an analysis of covariance model was used to detect significant Ca2+–cls interactions. We found that high-dimensional, morphological Ca2+–cls interactions were mixed with positive (86%) and negative (14%) chemical-genetic interactions, whereas one-dimensional fitness Ca2+–cls interactions were all negative in principle. Clustering analysis with the interaction profiles revealed nine distinct gene groups, six of which were functionally associated. In addition, characterization of Ca2+–cls interactions revealed that morphology-based negative interactions are unique signatures of sensitized cellular processes and pathways. Principal component analysis was used to discriminate between suppression and enhancement of the Ca2+-sensitive phenotypes triggered by inactivation of calcineurin, a Ca2+-dependent phosphatase. Finally, similarity of the interaction profiles was used to reveal a connected network among the Ca2+ homeostasis units acting in different cellular compartments. Our analyses of high-dimensional chemical-genetic interaction profiles provide novel insights into the intracellular network of yeast Ca2+ homeostasis. PMID:28566553

Comparison of Chemical Constituents in Scrophulariae Radix Processed by Different Methods based on UFLC-MS Combined with Multivariate Statistical Analysis.

PubMed

Wang, Shengnan; Hua, Yujiao; Zou, Lisi; Liu, Xunhong; Yan, Ying; Zhao, Hui; Luo, Yiyuan; Liu, Juanxiu

2018-02-01

Scrophulariae Radix is one of the most popular traditional Chinese medicines (TCMs). Primary processing of Scrophulariae Radix is an important link which closely related to the quality of products in this TCM. The aim of this study is to explore the influence of different processing methods on chemical constituents in Scrophulariae Radix. The difference of chemical constituents in Scrophulariae Radix processed by different methods was analyzed by using ultra fast liquid chromatography-triple quadrupole-time of flight mass spectrometry coupled with principal component analysis and orthogonal partial least squares discriminant analysis. Furthermore, the contents of 12 index differential constituents in Scrophulariae Radix processed by different methods were simultaneously determined by using ultra fast liquid chromatography coupled with triple quadrupole-linear ion trap mass spectrometry. Gray relational analysis was performed to evaluate the different processed samples according to the contents of 12 constituents. All of the results demonstrated that the quality of Scrophulariae Radix processed by "sweating" method was better. This study will provide the basic information for revealing the change law of chemical constituents in Scrophulariae Radix processed by different methods and facilitating selection of the suitable processing method of this TCM. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Single-step enantioselective amino acid flux analysis by capillary electrophoresis using on-line sample preconcentration with chemical derivatization.

PubMed

Ptolemy, Adam S; Tran, Lara; Britz-McKibbin, Philip

2006-07-15

Capillary electrophoresis (CE) represents a versatile platform for integrating sample pretreatment with chemical analysis because of its ability to tune analyte electromigration and band dispersion properties in discontinuous electrolyte systems. In this article, a single-step method that combines on-line sample preconcentration with in-capillary chemical derivatization is developed for rapid, sensitive, and enantioselective analysis of micromolar levels of amino acids that lack intrinsic chromophores by CE with UV detection. Time-resolved electrophoretic studies revealed two distinct stages of amino acid band narrowing within the original long sample injection plug occurring both prior to and after in-capillary labeling via zone passing by ortho-phthalaldehyde/N-acetyl l-cysteine (OPA/NAC). This technique enabled direct analysis of d-amino acids in a 95% enantiomeric excess mixture with sub-micromolar detection limits and minimal sample handling, where the capillary functions as a preconcentrator, microreactor, and chiral selector. On-line sample preconcentration with chemical derivatization CE (SPCD-CE) was applied to study the enantioselective amino acid flux in Escherichia coli bacteria cultures, which demonstrated a unique l-Ala efflux into the extracellular medium. New strategies for high-throughput analyses of low-abundance metabolites are important for understanding fundamental physiological processes in bacteria required for screening the efficacy of new classes of antibiotics as well as altered metabolism in genetically modified mutant strains.

Stable-carbon isotope ratios for sourcing the nerve-agent precursor methylphosphonic dichloride and its products

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

Moran, James J.; Fraga, Carlos G.; Nims, Megan K.

The ability to connect a chemical threat agent to a specific batch of a synthetic precursor can provide a fingerprint to contribute to effective forensic investigations. Stable isotope analysis can leverage intrinsic, natural isotopic variability within the molecules of a threat agent to unlock embedded chemical fingerprints in the material. Methylphosphonic dichloride (DC) is a chemical precursor to the nerve agent sarin. It is converted to methylphosphonic difluoride (DF) as part of the sarin synthesis process. We used a suite of commercially available DC stocks to both evaluate the potential for δ13C analysis to be used as a fingerprinting toolmore » in sarin-related investigations and to develop sample preparation techniques (using chemical hydrolysis) that can simplify isotopic analysis of DC and its synthetic products. We demonstrate that natural isotopic variability in DC results in at least three distinct, isotope-resolved clusters within the thirteen stocks we analyzed. Isotopic variability in the carbon feedstock (i.e., methanol) used for DC synthesis is likely inherited by the DC samples we measured. We demonstrate that the hydrolysis of DC and DF to methylphosphonic acid (MPA) can be used as a preparative step for isotopic analysis because the reaction does not impart a measureable isotopic fractionation. MPA is more chemically stable, less toxic, and easier to handle than DC or DF. Further, the hydrolysis method we demonstrated can be applied to a suite of other precursors or to sarin itself, thereby providing a potentially valuable forensic tool.« less

Stable-Carbon Isotope Ratios for Sourcing the Nerve-Agent Precursor Methylphosphonic Dichloride and Its Products

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

Moran, James J.; Fraga, Carlos G.; Nims, Megan K.

The ability to connect a chemical threat agent to a specific batch of a synthetic precursor can provide a fingerprint to contribute to effective forensic investigations. Stable isotope analysis can leverage intrinsic, natural isotopic variability within the molecules of a threat agent to unlock embedded chemical fingerprints in the material. Methylphosphonic dichloride (DC) is a chemical precursor to the nerve agent sarin. DC is converted to methylphosphonic difluoride (DF) as part of the sarin synthesis process. We used a suite of commercially available DC stocks to both evaluate the potential for δ 13C analysis to be used as a fingerprintingmore » tool in sarin-related investigations and to develop sample preparation techniques (using chemical hydrolysis) that can simplify isotopic analysis of DC and its synthetic products. We demonstrate that natural isotopic variability in DC results in at least three distinct, isotope-resolved clusters within the thirteen stocks we analyzed. Isotopic variability in the carbon feedstock (i.e., methanol) used for DC synthesis is likely inherited by the DC samples we measured. Here, we demonstrate that the hydrolysis of DC and DF to methylphosphonic acid (MPA) can be used as a preparative step for isotopic analysis because the reaction does not impart a significant isotopic fractionation. MPA is more chemically stable, less toxic, and easier to handle than DC or DF. Further, the hydrolysis method we demonstrated can be applied to a suite of other precursors or to sarin itself, thereby providing a potentially valuable forensic tool.« less

Stable-Carbon Isotope Ratios for Sourcing the Nerve-Agent Precursor Methylphosphonic Dichloride and Its Products

DOE PAGES

Moran, James J.; Fraga, Carlos G.; Nims, Megan K.

2018-04-01

The ability to connect a chemical threat agent to a specific batch of a synthetic precursor can provide a fingerprint to contribute to effective forensic investigations. Stable isotope analysis can leverage intrinsic, natural isotopic variability within the molecules of a threat agent to unlock embedded chemical fingerprints in the material. Methylphosphonic dichloride (DC) is a chemical precursor to the nerve agent sarin. DC is converted to methylphosphonic difluoride (DF) as part of the sarin synthesis process. We used a suite of commercially available DC stocks to both evaluate the potential for δ 13C analysis to be used as a fingerprintingmore » tool in sarin-related investigations and to develop sample preparation techniques (using chemical hydrolysis) that can simplify isotopic analysis of DC and its synthetic products. We demonstrate that natural isotopic variability in DC results in at least three distinct, isotope-resolved clusters within the thirteen stocks we analyzed. Isotopic variability in the carbon feedstock (i.e., methanol) used for DC synthesis is likely inherited by the DC samples we measured. Here, we demonstrate that the hydrolysis of DC and DF to methylphosphonic acid (MPA) can be used as a preparative step for isotopic analysis because the reaction does not impart a significant isotopic fractionation. MPA is more chemically stable, less toxic, and easier to handle than DC or DF. Further, the hydrolysis method we demonstrated can be applied to a suite of other precursors or to sarin itself, thereby providing a potentially valuable forensic tool.« less

Stable-carbon isotope ratios for sourcing the nerve-agent precursor methylphosphonic dichloride and its products.

PubMed

Moran, James J; Fraga, Carlos G; Nims, Megan K

2018-08-15

The ability to connect a chemical threat agent to a specific batch of a synthetic precursor can provide a fingerprint to contribute to effective forensic investigations. Stable isotope analysis can leverage intrinsic, natural isotopic variability within the molecules of a threat agent to unlock embedded chemical fingerprints in the material. Methylphosphonic dichloride (DC) is a chemical precursor to the nerve agent sarin. DC is converted to methylphosphonic difluoride (DF) as part of the sarin synthesis process. We used a suite of commercially available DC stocks to both evaluate the potential for δ 13 C analysis to be used as a fingerprinting tool in sarin-related investigations and to develop sample preparation techniques (using chemical hydrolysis) that can simplify isotopic analysis of DC and its synthetic products. We demonstrate that natural isotopic variability in DC results in at least three distinct, isotope-resolved clusters within the thirteen stocks we analyzed. Isotopic variability in the carbon feedstock (i.e., methanol) used for DC synthesis is likely inherited by the DC samples we measured. We demonstrate that the hydrolysis of DC and DF to methylphosphonic acid (MPA) can be used as a preparative step for isotopic analysis because the reaction does not impart a significant isotopic fractionation. MPA is more chemically stable, less toxic, and easier to handle than DC or DF. Further, the hydrolysis method we demonstrated can be applied to a suite of other precursors or to sarin itself, thereby providing a potentially valuable forensic tool. Copyright © 2018. Published by Elsevier B.V.

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.

Fluid Inclusion Gas Analysis

DOE Data Explorer

Dilley, Lorie

2013-01-01

Fluid inclusion gas analysis for wells in various geothermal areas. Analyses used in developing fluid inclusion stratigraphy for wells and defining fluids across the geothermal fields. Each sample has mass spectrum counts for 180 chemical species.

Physical and chemical analysis of a Ni/H2 cell

NASA Technical Reports Server (NTRS)

Vaidyanathan, H.; Earl, M. W.; Kirkendall, T. D.

1991-01-01

A cycled aerospace nickel hydrogen (Ni/H2) cell was subjected to destructive physical analysis to determine the reason for a capacity loss after 5,967 cycles at 60 percent depth of discharge. The positive plates in the cell were analyzed in terms of chemical composition, active material utilization, charge efficiency, and thickness increase. The microstructure of a cross section of the positive plate was determined by backscattered electron image analysis. The results suggest that the capacity loss in the cell is caused by low charge acceptance and low active material utilization at the positive plate. The oxidized nickel species content of the positive plate increased due to corrosion of the nickel sintered skeleton. This appears to circumvent the orderly reaction of the active material. Microstructural analysis has indicated that a new phase of active material is formed with cycling.

Online-LASIL: Laser Ablation of Solid Samples in Liquid with online-coupled ICP-OES detection for direct determination of the stoichiometry of complex metal oxide thin layers.

PubMed

Bonta, Maximilian; Frank, Johannes; Taibl, Stefanie; Fleig, Jürgen; Limbeck, Andreas

2018-02-13

Advanced materials such as complex metal oxides are used in a wide range of applications and have further promising perspectives in the form of thin films. The exact chemical composition essentially influences the electronic properties of these materials which makes correct assessment of their composition necessary. However, due to high chemical resistance and in the case of thin films low absolute analyte amounts, this procedure is in most cases not straightforward and extremely time-demanding. Commonly applied techniques either lack in ease of use (i.e., solution-based analysis with preceding sample dissolution), or adequately accurate quantification (i.e., solid sampling techniques). An analysis approach which combines the beneficial aspects of solution-based analysis as well as direct solid sampling is Laser Ablation of a Sample in Liquid (LASIL). In this work, it is shown that the analysis of major as well as minor sample constituents is possible using a novel online-LASIL setup, allowing sample analysis without manual sample handling after placing it in an ablation chamber. Strontium titanate (STO) thin layers with different compositions were analyzed in the course of this study. Precision of the newly developed online-LASIL method is comparable to conventional wet chemical approaches. With only about 15-20 min required for the analysis per sample, time demand is significantly reduced compared to often necessary fusion procedures lasting multiple hours. Copyright © 2017 Elsevier B.V. All rights reserved.

Use of deferiprone for the treatment of hepatic iron storage disease in three hornbills.

PubMed

Sandmeier, Peter; Clauss, Marcus; Donati, Olivio F; Chiers, Koen; Kienzle, Ellen; Hatt, Jean-Michel

2012-01-01

3 hornbills (2 Papua hornbills [Aceros plicatus] and 1 longtailed hornbill [Tockus albocristatus]) were evaluated because of general listlessness and loss of feather glossiness. Because hepatic iron storage disease was suspected, liver biopsy was performed and formalin-fixed liver samples were submitted for histologic examination and quantitative image analysis (QIA). Additional frozen liver samples were submitted for chemical analysis. Birds also underwent magnetic resonance imaging (MRI) under general anesthesia for noninvasive measurement of liver iron content. Serum biochemical analysis and analysis of feed were also performed. Results of diagnostic testing indicated that all 3 hornbills were affected with hepatic iron storage disease. The iron chelator deferiprone was administered (75 mg/kg [34.1 mg/lb], PO, once daily for 90 days). During the treatment period, liver biopsy samples were obtained at regular intervals for QIA and chemical analysis of the liver iron content and follow-up MRI was performed. In all 3 hornbills, a rapid and large decrease in liver iron content was observed. All 3 methods for quantifying the liver iron content were able to verify the decrease in liver iron content. Orally administered deferiprone was found to effectively reduce the liver iron content in these 3 hornbills with iron storage disease. All 3 methods used to monitor the liver iron content (QIA, chemical analysis of liver biopsy samples, and MRI) had similar results, indicating that all of these methods should be considered for the diagnosis of iron storage disease and monitoring of liver iron content during treatment.

Development of a security vulnerability assessment process for the RAMCAP chemical sector.

PubMed

Moore, David A; Fuller, Brad; Hazzan, Michael; Jones, J William

2007-04-11

The Department of Homeland Security (DHS), Directorate of Information Analysis & Infrastructure Protection (IAIP), Protective Services Division (PSD), contracted the American Society of Mechanical Engineers Innovative Technologies Institute, LLC (ASME ITI, LLC) to develop guidance on Risk Analysis and Management for Critical Asset Protection (RAMCAP). AcuTech Consulting Group (AcuTech) has been contracted by ASME ITI, LLC, to provide assistance by facilitating the development of sector-specific guidance on vulnerability analysis and management for critical asset protection for the chemical manufacturing, petroleum refining, and liquefied natural gas (LNG) sectors. This activity involves two key tasks for these three sectors: Development of a screening to supplement DHS understanding of the assets that are important to protect against terrorist attack and to prioritize the activities. Development of a standard security vulnerability analysis (SVA) framework for the analysis of consequences, vulnerabilities, and threats. This project involves the cooperative effort of numerous leading industrial companies, industry trade associations, professional societies, and security and safety consultants representative of those sectors. Since RAMCAP is a voluntary program for ongoing risk management for homeland security, sector coordinating councils are being asked to assist in communicating the goals of the program and in encouraging participation. The RAMCAP project will have a profound and positive impact on all sectors as it is fully developed, rolled-out and implemented. It will help define the facilities and operations of national and regional interest for the threat of terrorism, define standardized methods for analyzing consequences, vulnerabilities, and threats, and describe best security practices of the industry. This paper will describe the results of the security vulnerability analysis process that was developed and field tested for the chemical manufacturing sector. This method was developed through the cooperation of the many organizations and the individuals involved from the chemical sector RAMCAP development activities. The RAMCAP SVA method is intended to provide a common basis for making vulnerability assessments and risk-based decisions for homeland security. Mr. Moore serves as the coordinator for the chemical manufacturing, petroleum refining, and LNG sectors for the RAMCAP project and Dr. Jones is the chief technology officer for ASME-ITI, LLC for RAMCAP.

Surface-enhanced Raman sensor for trace chemical detection in water

NASA Astrophysics Data System (ADS)

Lee, Vincent Y.; Farquharson, Stuart; Rainey, Petrie M.

1999-11-01

Surface-enhanced Raman spectroscopy (SERS) promises to be one of the most sensitive methods for chemical detection and in recent years SERS has been used for chemical, biochemical, environmental, and physiological applications. A variety of methods using various media (electrodes, colloids, and substrates) have been successfully developed to enhance Raman signals by six orders of magnitude and more. However, SERS has not become a routine analytical technique because these methods are unable to provide quantitative measurements. This is largely due to the inability to fabricate a sampling medium that provides reversible chemical adsorption, analysis-to-analysis reproducibility, unrestricted solution requirements (reagent concentration and pH) or sample phase (liquid or solid). In an effort to overcome these restrictions, we have developed metal-doped sol-gels to provide surface-enhancement of Raman scattering.

Factors affecting the use of 13Cα chemical shifts to determine, refine, and validate protein structures

PubMed Central

Vila, Jorge A.; Scheraga, Harold A.

2008-01-01

Interest centers here on the analysis of two different, but related, phenomena that affect side-chain conformations and consequently 13Cα chemical shifts and their applications to determine, refine, and validate protein structures. The first is whether 13Cα chemical shifts, computed at the DFT level of approximation with charged residues is a better approximation of observed 13Cα chemical shifts than those computed with neutral residues for proteins in solution. Accurate computation of 13Cα chemical shifts requires a proper representation of the charges, which might not take on integral values. For this analysis, the charges for 139 conformations of the protein ubiquitin were determined by explicit consideration of protein binding equilibria, at a given pH, that is, by exploring the 2ξ possible ionization states of the whole molecule, with ξ being the number of ionizable groups. The results of this analysis, as revealed by the shielding/deshield-ing of the 13Cα nucleus, indicated that: (i) there is a significant difference in the computed 13Cα chemical shifts, between basic and acidic groups, as a function of the degree of charge of the side chain; (ii) this difference is attributed to the distance between the ionizable groups and the 13Cα nucleus, which is shorter for the acidic Asp and Glu groups as compared with that for the basic Lys and Arg groups; and (iii) the use of neutral, rather than charged, basic and acidic groups is a better approximation of the observed 13Cα chemical shifts of a protein in solution. The second is how side-chain flexibility influences computed 13Cα chemical shifts in an additional set of ubiquitin conformations, in which the side chains are generated from an NMR-derived structure with the backbone conformation assumed to be fixed. The 13Cα chemical shift of a given amino acid residue in a protein is determined, mainly, by its own backbone and side-chain torsional angles, independent of the neighboring residues; the conformation of a given residue itself, however, depends on the environment of this residue and, hence, on the whole protein structure. As a consequence, this analysis reveals the role and impact of an accurate side-chain computation in the determination and refinement of protein conformation. The results of this analysis are: (i) a lower error between computed and observed 13Cα chemical shifts (by up to 3.7 ppm), was found for ~68% and ~63% of all ionizable residues and all non-Ala/Pro/Gly residues, respectively, in the additional set of conformations, compared with results for the model from which the set was derived; and (ii) all the additional conformations exhibit a lower root-mean-square-deviation (1.97 ppm ≤ rmsd ≤ 2.13 ppm), between computed and observed 13Cα chemical shifts, than the rmsd (2.32 ppm) computed for the starting conformation from which this additional set was derived. As a validation test, an analysis of the additional set of ubiquitin conformations, comparing computed and observed values of both 13Cα chemical shifts and χ1 torsional angles (given by the vicinal coupling constants, 3JN–Cγ and 3JC′–Cγ, is discussed. PMID:17975838

40 CFR 63.11502 - What definitions apply to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

...: process knowledge, an engineering assessment, or test data. Byproduct means a chemical (liquid, gas, or... limit applicable to the process vent. (4) Design analysis based on accepted chemical engineering... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Chemical Manufacturing Area Sources...

40 CFR 63.11502 - What definitions apply to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

...: process knowledge, an engineering assessment, or test data. Byproduct means a chemical (liquid, gas, or... limit applicable to the process vent. (4) Design analysis based on accepted chemical engineering... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Chemical Manufacturing Area Sources...

Meta-Analysis of the Chemical and Non-Chemical Stressors Affecting Childhood Obesity?

EPA Science Inventory

Background: Worldwide, approximately 42 million children under the age of 5 years are considered overweight or obese. While much research has focused on individual behaviors impacting obesity, little research has emphasized the complex interactions of numerous chemical and non-ch...

INVERSE QUANTITATIVE STRUCTURE ACTIVITY RELATIONSHIP ANALYSIS FOR IMPROVING PREDICTIONS OF CHEMICAL TOXICITY

EPA Science Inventory

The toxic outcomes associated with environmental contaminants are often not due to the chemical form that was originally introduced into the environment, but rather to the chemical having undergone a transformation prior to reaching the vulnerable species. More importantly, the c...

TOXICOGENOMIC STUDY OF TRIAZOLE FUNGICIDES AND PERFLUOROALKYL ACIDS IN RAT LIVERS ACCURATELY CATEGORIZES CHEMICALS AND IDENTIFIES MECHANISMS OF TOXICITY

EPA Science Inventory

Toxicogenomic analysis of five environmental chemicals was performed to investigate the ability of genomics to predict toxicity, categorize chemicals, and elucidate mechanisms of toxicity. Three triazole antifungals (myclobutanil, propiconazole, and triadimefon) and two perfluori...

40 CFR 796.2750 - Sediment and soil adsorption isotherm.

Code of Federal Regulations, 2014 CFR

2014-07-01

... are highly reproducible. The test provides excellent quantitative data readily amenable to statistical... combination of methods suitable for the identification and quantitative detection of the parent test chemical... quantitative analysis of the parent chemical. (3) Amount of parent test chemical applied, the amount recovered...

40 CFR 796.2750 - Sediment and soil adsorption isotherm.

Code of Federal Regulations, 2013 CFR

2013-07-01

... highly reproducible. The test provides excellent quantitative data readily amenable to statistical... combination of methods suitable for the identification and quantitative detection of the parent test chemical... quantitative analysis of the parent chemical. (3) Amount of parent test chemical applied, the amount recovered...

40 CFR 796.2750 - Sediment and soil adsorption isotherm.

Code of Federal Regulations, 2012 CFR

2012-07-01

... highly reproducible. The test provides excellent quantitative data readily amenable to statistical... combination of methods suitable for the identification and quantitative detection of the parent test chemical... quantitative analysis of the parent chemical. (3) Amount of parent test chemical applied, the amount recovered...

Exposomics research using suspect screening and non ...

EPA Pesticide Factsheets

High-resolution mass spectrometry (HRMS) is used for suspect screening (SSA) and non-targeted analysis (NTA) in an attempt to characterize xenobiotic chemicals in various samples broadly and efficiently. These important techniques aid characterization of the exposome, the totality of human exposures, and provide critical information on thousands of chemicals in commerce for which exposure data are lacking. The Environmental Protection Agency (EPA) SSA and NTA capabilities consist of analytical instrumentation [liquid chromatography (LC) with time of flight (TOF) and quadrupole-TOF (Q-TOF) HRMS], workflows (feature extraction, formula generation, structure prediction, spectral matching, chemical confirmation), and tools (databases; models for predicting retention time, functional use, media occurrence, and media concentration; and schemes for ranking features and chemicals). Suspect screening (SSA) and non-targeted analysis (NTA) are used to characterize xenobiotic chemicals in various samples and aid characterization of the exposome, the totality of human exposures, and provide critical information on thousands of chemicals in commerce for which exposure data are lacking.

Sum over Histories Representation for Kinetic Sensitivity Analysis: How Chemical Pathways Change When Reaction Rate Coefficients Are Varied

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

Bai, Shirong; Davis, Michael J.; Skodje, Rex T.

2015-11-12

The sensitivity of kinetic observables is analyzed using a newly developed sum over histories representation of chemical kinetics. In the sum over histories representation, the concentrations of the chemical species are decomposed into the sum of probabilities for chemical pathways that follow molecules from reactants to products or intermediates. Unlike static flux methods for reaction path analysis, the sum over histories approach includes the explicit time dependence of the pathway probabilities. Using the sum over histories representation, the sensitivity of an observable with respect to a kinetic parameter such as a rate coefficient is then analyzed in terms of howmore » that parameter affects the chemical pathway probabilities. The method is illustrated for species concentration target functions in H-2 combustion where the rate coefficients are allowed to vary over their associated uncertainty ranges. It is found that large sensitivities are often associated with rate limiting steps along important chemical pathways or by reactions that control the branching of reactive flux« less

Thermodynamic analysis of alternate energy carriers, hydrogen and chemical heat pipes

NASA Technical Reports Server (NTRS)

Cox, K. E.; Carty, R. H.; Conger, W. L.; Soliman, M. A.; Funk, J. E.

1976-01-01

The paper discusses the production concept and efficiency of two new energy transmission and storage media intended to overcome the disadvantages of electricity as an overall energy carrier. These media are hydrogen produced by water-splitting and the chemical heat pipe. Hydrogen can be transported or stored, and burned as energy is needed, forming only water and thus obviating pollution problems. The chemical heat pipe envisions a system in which heat is stored as the heat of reaction in chemical species. The thermodynamic analysis of these two methods is discussed in terms of first-law and second-law efficiency. It is concluded that chemical heat pipes offer large advantages over thermochemical hydrogen generation schemes on a first-law efficiency basis except for the degradation of thermal energy in temperature thus providing a source of low-temperature (800 K) heat for process heat applications. On a second-law efficiency basis, hydrogen schemes are superior in that the amount of available work is greater as compared to chemical heat pipes.

Chemical Facility Preparedness: A Comprehensive Approach

DTIC Science & Technology

2006-09-01

25 E. SWOT ANALYSIS & STRATEGIC ISSUE DEVELOPMENT ..............27 1. What can DHS do to Improve...be calculated and reviewed. Continuous benchmarking against best practices will be a necessity. E. SWOT ANALYSIS & STRATEGIC ISSUE DEVELOPMENT...In order to identify strategic issues for DHS, a Strength, Weakness, Opportunity and Threat ( SWOT ) analysis is necessary. Conducting this kind of

75 FR 19319 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting; Extension of Comment...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-14

... Analysis Division, Office of Information Analysis and Access (2842T), Environmental Protection Agency, 1200.... Martin, Acting Director, Office of Information Analysis and Access. [FR Doc. 2010-8527 Filed 4-13-10; 8... comments. E-mail: [email protected] . Mail: Office of Environmental Information (OEI) Docket...

Abuse of guaifenesin-containing medications generates an excess of a carboxylate salt of beta-(2-methoxyphenoxy)-lactic acid, a guaifenesin metabolite, and results in urolithiasis.

PubMed

Pickens, C L; Milliron, A R; Fussner, A L; Dversdall, B C; Langenstroer, P; Ferguson, S; Fu, X; Schmitz, F J; Poole, E C

1999-07-01

Several urinary calculi were submitted to our institution for compositional analysis. The typical techniques of analysis, polarized light microscopy, electron microprobe analysis, and infrared spectroscopy proved inadequate for a definitive identification. As a result, a more detailed organic analysis was conducted to determine the exact chemical structure of the material. Infrared spectroscopy and mass spectrometric analysis were carried out on the solid material, providing information concerning the functional groups and the molecular mass of the organic constituent and its components. The stone was solubilized in deuterated solvents and analyzed by nuclear magnetic resonance spectroscopy, which resulted in a definitive chemical structure. The spectroscopic analysis indicated that the stones were composed of a calcium salt of beta-(2-methoxyphenoxy)-lactic acid, a metabolite of the pharmaceutical guaifenesin, which is used as an expectorant. Guaifenesin, an expectorant common in over-the-counter cold and allergy remedies, can cause urolithiasis if taken in excess. Discussions with physicians and their patients confirmed that most patients admitted to taking large doses of guaifenesin-containing medications.

Acceleration and sensitivity analysis of lattice kinetic Monte Carlo simulations using parallel processing and rate constant rescaling

NASA Astrophysics Data System (ADS)

Núñez, M.; Robie, T.; Vlachos, D. G.

2017-10-01

Kinetic Monte Carlo (KMC) simulation provides insights into catalytic reactions unobtainable with either experiments or mean-field microkinetic models. Sensitivity analysis of KMC models assesses the robustness of the predictions to parametric perturbations and identifies rate determining steps in a chemical reaction network. Stiffness in the chemical reaction network, a ubiquitous feature, demands lengthy run times for KMC models and renders efficient sensitivity analysis based on the likelihood ratio method unusable. We address the challenge of efficiently conducting KMC simulations and performing accurate sensitivity analysis in systems with unknown time scales by employing two acceleration techniques: rate constant rescaling and parallel processing. We develop statistical criteria that ensure sufficient sampling of non-equilibrium steady state conditions. Our approach provides the twofold benefit of accelerating the simulation itself and enabling likelihood ratio sensitivity analysis, which provides further speedup relative to finite difference sensitivity analysis. As a result, the likelihood ratio method can be applied to real chemistry. We apply our methodology to the water-gas shift reaction on Pt(111).

Phthalic acid chemical probes synthesized for protein-protein interaction analysis.

PubMed

Liang, Shih-Shin; Liao, Wei-Ting; Kuo, Chao-Jen; Chou, Chi-Hsien; Wu, Chin-Jen; Wang, Hui-Min

2013-06-24

Plasticizers are additives that are used to increase the flexibility of plastic during manufacturing. However, in injection molding processes, plasticizers cannot be generated with monomers because they can peel off from the plastics into the surrounding environment, water, or food, or become attached to skin. Among the various plasticizers that are used, 1,2-benzenedicarboxylic acid (phthalic acid) is a typical precursor to generate phthalates. In addition, phthalic acid is a metabolite of diethylhexyl phthalate (DEHP). According to Gene_Ontology gene/protein database, phthalates can cause genital diseases, cardiotoxicity, hepatotoxicity, nephrotoxicity, etc. In this study, a silanized linker (3-aminopropyl triethoxyslane, APTES) was deposited on silicon dioxides (SiO2) particles and phthalate chemical probes were manufactured from phthalic acid and APTES-SiO2. These probes could be used for detecting proteins that targeted phthalic acid and for protein-protein interactions. The phthalic acid chemical probes we produced were incubated with epithelioid cell lysates of normal rat kidney (NRK-52E cells) to detect the interactions between phthalic acid and NRK-52E extracted proteins. These chemical probes interacted with a number of chaperones such as protein disulfide-isomerase A6, heat shock proteins, and Serpin H1. Ingenuity Pathways Analysis (IPA) software showed that these chemical probes were a practical technique for protein-protein interaction analysis.

Standardization of Cassia spectabilis with respect to authenticity, assay and chemical constituent analysis.

PubMed

Torey, Angeline; Sasidharan, Sreenivasan; Yeng, Chen; Latha, Lachimanan Yoga

2010-05-10

Quality control standardizations of the various medicinal plants used in traditional medicine is becoming more important today in view of the commercialization of formulations based on these plants. An attempt at standardization of Cassia spectabilis leaf has been carried out with respect to authenticity, assay and chemical constituent analysis. The authentication involved many parameters, including gross morphology, microscopy of the leaves and functional group analysis by Fourier Transform Infrared (FTIR) spectroscopy. The assay part of standardization involved determination of the minimum inhibitory concentration (MIC) of the extract which could help assess the chemical effects and establish curative values. The MIC of the C. spectabilis leaf extracts was investigated using the Broth Dilution Method. The extracts showed a MIC value of 6.25 mg/mL, independent of the extraction time. The chemical constituent aspect of standardization involves quantification of the main chemical components in C. spectabilis. The GCMS method used for quantification of 2,4-(1H,3H)-pyrimidinedione in the extract was rapid, accurate, precise, linear (R(2) = 0.8685), rugged and robust. Hence this method was suitable for quantification of this component in C. spectabilis. The standardization of C. spectabilis is needed to facilitate marketing of medicinal plants, with a view to promoting the export of valuable Malaysian Traditional Medicinal plants such as C. spectabilis.

The challenge of predicting problematic chemicals using a decision analysis tool: Triclosan as a case study.

PubMed

Perez, Angela L; Gauthier, Alison M; Ferracini, Tyler; Cowan, Dallas M; Kingsbury, Tony; Panko, Julie

2017-01-01

Manufacturers lack a reliable means for determining whether a chemical will be targeted for deselection from their supply chain. In this analysis, 3 methods for determining whether a specific chemical (triclosan) would meet the criteria necessary for being targeted for deselection are presented. The methods included a list-based approach, use of a commercially available chemical assessment software tool run in 2 modes, and a public interest evaluation. Our results indicated that triclosan was included on only 6 of the lists reviewed, none of which were particularly influential in chemical selection decisions. The results from the chemical assessment tool evaluations indicated that human and ecological toxicity for triclosan is low and received scores indicating that the chemical would be considered of low concern. However, triclosan's peak public interest tracked several years in advance of increased regulatory scrutiny of this chemical suggesting that public pressure may have been influential in deselection decisions. Key data gaps and toxicity endpoints not yet regulated such as endocrine disruption potential or phototoxicity, but that are important to estimate the trajectory for deselection of a chemical, are discussed. Integr Environ Assess Manag 2017;13:198-207. © 2016 SETAC. © 2016 SETAC.

An Inventory for Measuring Student Teachers' Knowledge of Chemical Representations: Design, Validation, and Psychometric Analysis

ERIC Educational Resources Information Center

Taskin, V.; Bernholt, S.; Parchmann, I.

2015-01-01

Chemical representations play an important role in helping learners to understand chemical contents. Thus, dealing with chemical representations is a necessity for learning chemistry, but at the same time, it presents a great challenge to learners. Due to this great challenge, it is not surprising that numerous national and international studies…

Chemical Applications for Enhanced World Security

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

Leibman, Christopher Patrick

The purpose of this project is to reduce complexity of chemical analysis by combining chemical and physical processing steps into on package; develop instrumentation that cost less and is easy to use in a field laboratory by non-experts; and develop this "chemical application" so uranium enrichment can be measured onsite, eliminating the need for radioactive sample transport.

Laser-induced fluorescence spectroscopy for improved chemical analysis

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

Gelbwachs, J.A.

1983-09-01

This report summarizes the progress achieved over the past five years in the laser-induced fluorescence spectroscopy (LIFS) for improved chemical analysis program. Our initial efforts yielded significantly lower detection limits for trace elemental analysis by the use of both cw and pulsed laser excitations. New methods of LIFS were developed that were shown to overcome many of the traditional limitations to LIFS techniques. LIFS methods have been applied to yield fundamental scientific data that further the understanding of forces between atoms and other atoms and molecules. In recent work, two-photon ionization was combined with LIFS and applied, for the firstmore » time, to the study of energy transfer in ions.« less

Program Package for the Analysis of High Resolution High Signal-To-Noise Stellar Spectra

NASA Astrophysics Data System (ADS)

Piskunov, N.; Ryabchikova, T.; Pakhomov, Yu.; Sitnova, T.; Alekseeva, S.; Mashonkina, L.; Nordlander, T.

2017-06-01

The program package SME (Spectroscopy Made Easy), designed to perform an analysis of stellar spectra using spectral fitting techniques, was updated due to adding new functions (isotopic and hyperfine splittins) in VALD and including grids of NLTE calculations for energy levels of few chemical elements. SME allows to derive automatically stellar atmospheric parameters: effective temperature, surface gravity, chemical abundances, radial and rotational velocities, turbulent velocities, taking into account all the effects defining spectral line formation. SME package uses the best grids of stellar atmospheres that allows us to perform spectral analysis with the similar accuracy in wide range of stellar parameters and metallicities - from dwarfs to giants of BAFGK spectral classes.

Spray drying egg using either maltodextrin or nopal mucilage as stabilizer agents.

PubMed

Medina-Torres, L; Calderas, F; Nuñez Ramírez, D M; Herrera-Valencia, E E; Bernad Bernad, M J; Manero, O

2017-12-01

In this work, a comparative study between spray drying (SD) of fresh egg by either maltodextrin (MD) or nopal-mucilage (MN) as stabilizing vectors was made. The powders obtained were characterized for drying performance, moisture content, chemical proximate analysis, thermal analysis (TGA), chemical composition (FTIR), microscopy (SEM) and rheology (viscoelasticity and steady state simple shear viscosity). Infrared analysis showed that MN has the effect of a thickening agent rather than an encapsulating one. Results indicated that SD egg with MN produced a high thermal and mechanical stable product and rendered the highest drying performance, producing a more uniform and defined sphere-shaped morphology in comparison to egg SD either alone and with MD.

Topics in Chemical Instrumentation.

ERIC Educational Resources Information Center

Settle, Frank A. Jr., Ed.

1989-01-01

Using Fourier transformation methods in nuclear resonance has made possible increased sensitivity in chemical analysis. This article describes data acquisition, data processing, and the frequency spectrum as they relate to this technique. (CW)

40 CFR 469.41 - Specialized definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... voltage, chemical reactions or mechanical energy and which are specifically used as coatings in... Subcategory § 469.41 Specialized definitions. The definitions in 40 CFR part 401 and the chemical analysis...

40 CFR 469.41 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... voltage, chemical reactions or mechanical energy and which are specifically used as coatings in... Subcategory § 469.41 Specialized definitions. The definitions in 40 CFR part 401 and the chemical analysis...

Vibrational spectroscopic, molecular docking and quantum chemical studies on 6-aminonicotinamide

NASA Astrophysics Data System (ADS)

Mohamed Asath, R.; Premkumar, S.; Mathavan, T.; Milton Franklin Benial, A.

2017-04-01

The most stable molecular structure of 6-aminonicotinamide (ANA) molecule was predicted by conformational analysis and vibrational spectral analysis was carried out by experimental and theoretical methods. The calculated and experimentally observed vibrational frequencies were assigned and compared. The π→π* electronic transition of the molecule was predicted by theoretically calculated ultraviolet-visible spectra in gas and liquid phase and further validated experimentally using ethanol as a solvent. Frontier molecular orbitals analysis was carried out to probe the reactive nature of the ANA molecule and further the site selectivity to specific chemical reactions were effectively analyzed by Fukui function calculation. The molecular electrostatic potential surface was simulated to confirm the reactive sites of the molecule. The natural bond orbital analysis was also performed to understand the intra molecular interactions, which confirms the bioactivity of the ANA molecule. Neuroprotective nature of the ANA molecule was analyzed by molecular docking analysis and the ANA molecule was identified as a good inhibitor against Alzheimer's disease.

Composition analysis of a polymer electrolyte membrane fuel cell microporous layer using scanning transmission X-ray microscopy and near edge X-ray absorption fine structure analysis

NASA Astrophysics Data System (ADS)

George, Michael G.; Wang, Jian; Banerjee, Rupak; Bazylak, Aimy

2016-03-01

The novel application of scanning transmission X-ray microscopy (STXM) to the microporous layer (MPL) of a polymer electrolyte membrane fuel cell is investigated. A spatially resolved chemical component distribution map is obtained for the MPL of a commercially available SGL 25 BC sample. This is achieved with near edge X-ray absorption fine structure spectroscopic analysis. Prior to analysis the sample is embedded in non-reactive epoxy and ultra-microtomed to a thickness of 100 nm. Polytetrafluoroethylene (PTFE), carbon particle agglomerates, and supporting epoxy resin distributions are identified and reconstructed for a scanning area of 6 μm × 6 μm. It is observed that the spatial distribution of PTFE is strongly correlated to the carbon particle agglomerations. Additionally, agglomerate structures of PTFE are identified, possibly indicating the presence of a unique mesostructure in the MPL. STXM analysis is presented as a useful technique for the investigation of chemical species distributions in the MPL.

A Novel Approach to Detect Accelerated Aged and Surface-Mediated Degradation in Explosives by UPLC-ESI-MS.

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

Beppler, Christina L

2015-12-01

A new approach was created for studying energetic material degradation. This approach involved detecting and tentatively identifying non-volatile chemical species by liquid chromatography-mass spectrometry (LC-MS) with multivariate statistical data analysis that form as the CL-20 energetic material thermally degraded. Multivariate data analysis showed clear separation and clustering of samples based on sample group: either pristine or aged material. Further analysis showed counter-clockwise trends in the principal components analysis (PCA), a type of multivariate data analysis, Scores plots. These trends may indicate that there was a discrete shift in the chemical markers as the went from pristine to aged material, andmore » then again when the aged CL-20 mixed with a potentially incompatible material was thermally aged for 4, 6, or 9 months. This new approach to studying energetic material degradation should provide greater knowledge of potential degradation markers in these materials.« less

Energy and economic analysis of the carbon dioxide capture installation with the use of monoethanolamine and ammonia

NASA Astrophysics Data System (ADS)

Bochon, Krzysztof; Chmielniak, Tadeusz

2015-03-01

In the study an accurate energy and economic analysis of the carbon capture installation was carried out. Chemical absorption with the use of monoethanolamine (MEA) and ammonia was adopted as the technology of carbon dioxide (CO2) capture from flue gases. The energy analysis was performed using a commercial software package to analyze the chemical processes. In the case of MEA, the demand for regeneration heat was about 3.5 MJ/kg of CO2, whereas for ammonia it totalled 2 MJ/kg CO2. The economic analysis was based on the net present value (NPV) method. The limit price for CO2 emissions allowances at which the investment project becomes profitable (NPV = 0) was more than 160 PLN/Mg for MEA and less than 150 PLN/Mg for ammonia. A sensitivity analysis was also carried out to determine the limit price of CO2 emissions allowances depending on electricity generation costs at different values of investment expenditures.

Recent progress on mid-IR sensing with optical fibers

NASA Astrophysics Data System (ADS)

Kellner, Robert A.; Gobel, R.; Goetz, R.; Lendl, B.; Edl-Mizaikoff, B.; Tacke, Maurus; Katzir, Abraham

1995-09-01

Chemical sensors are analytical systems for the evaluation of compound- or ion-specific or - selective signals produced by specific or selective chemical reactions taking place at the interface between the chemically modified sensor surface and the substrate. The well known electrochemical sensing schemes have greatly contributed that sensors are considered now as the 'third supporting pillar of analytical chemistry' besides chromatography and spectroscopy. The aim of this paper is to describe the novel capabilities of chemical modified IR-transparent fibers as chemical IR-sensors for the on-line analysis of chlorinated hydrocarbons and organic compounds in aqueous solutions and gaseous mixtures, glucose, and sucrose in aqueous solution as developed in our laboratory. Moreover, the relative merits of this new method wil be depicted in comparison to other sensing techniques. Optical fiber sensors are novel analysis systems, based on molecular spectroscopy in the UV/VIS/IR-range. They benefit from the tremendous development in the field of optical fibers, an offspring of the telecommunication industry and the electronic revolution during the last few years. With the development of new materials besides the well known quartz fibers for the UV/VIS/NIR-range the optical window for fiber optic sensors was enlarged from 0,2 to 20 micrometers recently. The fiber length was increased recently to up to 2 meters for silver halides and approximately 10 meters for chalcogenides. New applications for environmental, food, and clinical sensing as well as process analysis are the driving force for modern research in IR-optical fiber sensors using mainly sapphire (Al2O3), chalcogenide (As-Se-Te) and silver halide (AgBr/AgCl) fibers and flow injection analysis (FIA) systems. Few representative examples for each of the various optical sensor types will be presented. Particular attention will be given to the use of silver halide fibers for the simultaneous determination of traces of chlorinated hydrocarbons in water and to FIA-systems for the process analysis of beverages.

Failure Analysis of a Service Tube

NASA Astrophysics Data System (ADS)

Xie, Zhongdong; Cai, Weiguo; Li, Zhenxing; Guan, YiMing; Zhang, Baocheng; Yang, XiaoTong

2017-12-01

One tube was cracked used in the primary reformer furnace in a fertilizer plant for two and half years. In order to find out the causes of cracking, the methods for chemical composition analysis, macro- and microstructure analysis, penetrant testing, weld analysis, crack and surface damage analysis, mechanics property analysis, high temperature endurance performance analysis, stress and wall thickness calculation were adopted. The integrated assessment results showed that the carbon content of the tube was in the lower limit of the standard range; the tube effective wall thickness was too small; local overheating leads to tube cracking in use process.